Dr Xianfeng Liu
Honorary Associate Professor
School of Engineering
- Email:xianfeng.liu@newcastle.edu.au
- Phone:(02) 4921 5331
Career Summary
Biography
Dr Xianfeng Liu completed his bachelor and master degrees in Southwest Jiaotong University (China) in 2005 and obtained a PhD in Geomechanics in 2010 from Ecole Centrale de Nantes (France). After a Postdoc position in ECN, he joined the University of Newcastle in 2011 where he now is Research Academic. His research spans from experimental unsaturated soils to rock mechanics and geoenvironmental engineering as well as soil dynamics.
Qualifications
- PhD, Ecole Centrale de Nantes - France
- Master of Engineering, Southwest Jiaotong University - China
Keywords
- Contaminants transport in soils
- Multi-physics modelling (THMC)
- Soil dynamics
- Unsaturated soils
Languages
- French (Fluent)
- Mandarin (Mother)
- English (Fluent)
Publications
For publications that are currently unpublished or in-press, details are shown in italics.
Chapter (1 outputs)
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2018 |
Momenzadeh L, Moghtaderi B, Liu X, Sloan S, Belova I, Murch G, 'The Thermal Conductivity of Magnesite, Dolomite and Calcite as Determined by Molecular Dynamics Simulation', Diffusion Foundations and Materials Applications, Scientific.Net, Baech, Switzerland 18-34 (2018) [B1]
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Journal article (63 outputs)
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2024 |
Pan GF, Zheng YX, Yuan SY, Sun DX, Buzzi O, Jiang GL, Liu XF, 'Microstructural insight into the hysteretic water retention behavior of intact Mile expansive clay', Soils and Foundations, 64 (2024) [C1] Water retention behavior of clayey soils usually exhibits a hysteretic phenomenon, which can be attributed to the ink-bottle effect, different contact angle during wetting and dry... [more] Water retention behavior of clayey soils usually exhibits a hysteretic phenomenon, which can be attributed to the ink-bottle effect, different contact angle during wetting and drying process, entrapped air etc. For expansive soils, along the wetting and drying path, significant microstructure change is usually observed. The effect of microstructure change on the water retention hysteretic phenomenon was studied in this paper for an intact expansive clay from China, Mile clay. The soil water retention curve of Mile clay was obtained at the full suction range. The evolution of microstructure along wetting and drying path for Mile clay was characterized by pore sized distribution obtained from mercury intrusion porosimetry tests. Test results show that a strong hysteretic phenomenon was observed for suction ranging between 40 kPa and 15 MPa. This hysteretic phenomenon was mainly contributed to the different microstructure of specimens along wetting and drying paths with similar water ratio. For higher suction, as adsorption mechanism mainly contributed to the water retention properties, for specimens with similar water ratio, even with different maximum filled entrance pore sizes, the corresponding suction were similar with each other. For the lower suction, due to the completely drying historical state of specimens on the main wetting path, slightly different pore size distributions were observed for specimens on the main wetting and drying path with similar water ratio.
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2024 |
Zhang C, Tian K, Yuan S, Zhai W, Min Q, Song J, et al., 'Stability of shallow-buried Qanat foundation under cyclic load', Journal of Railway Science and Engineering, 21 183-193 (2024) Qanat is an underground water engineering structure widely distributed in western and central Asia, and Xinjiang region of China. With the proposal of the ¿Belt and Road Initiativ... [more] Qanat is an underground water engineering structure widely distributed in western and central Asia, and Xinjiang region of China. With the proposal of the ¿Belt and Road Initiative¿, the newly construction of high-speed railway will inevitably encounter the problem of intersection with qanat in the above areas. The hidden shallow qanat culverts under low embankments may collapse under the load of high-speed trains, affecting the stability of the upper foundation and subgrade. A large-scale model test was utilized to study the stability of shallow qanat foundation under cyclic load. The earth pressure and the compression deformation characteristics affect by qanat depth was discussed, while the potential failure surface of soil mass was analyzed combined with PIV technology. The results aredrawnas follows. The earth pressure above the culvert changes from ¿first increasing and then decreasing¿ to ¿continuously decreasing¿ along the surface depth with the increase of cyclic load, and are eventually all smaller than both sides of the horizontal. Meanwhile, increasing the qanat depth can also reduce the surface settlement rate and increase the ultimate cyclic load which foundation structure can bear. However, the accumulated settlement will increase when the qanat structure completely collapsed. The critical cyclic load frequency for the surface begin to appear large deformation are all 5~10 Hz for each foundation, and the high deformation area of foundation changes from ¿inverted cone type¿ to ¿funnel type¿ with the increase of qanat depth. When the buried depth reaches 7.5D (D is the diameter of the qanat), the potential sliding failure surface only extends above the qanat, indicating the effect of cyclic load has a critical turning point between 5.5D and 7.5D. The results provide a reference for the stability analysis and reinforcement treatment of high-speed railway foundation in the qanat region.
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2023 |
Zhang Y, Liu X, Yuan S, Song J, Chen W, Dias D, 'A two-dimensional experimental study of active progressive failure of deeply buried Qanat tunnels in sandy ground', Soils and Foundations, 63 (2023) [C1] As an ancient underground hydraulic engineering facility, the Qanat system has been used to draw groundwater from arid regions. A qanat is a horizontal tunnel with a slight inclin... [more] As an ancient underground hydraulic engineering facility, the Qanat system has been used to draw groundwater from arid regions. A qanat is a horizontal tunnel with a slight incline that draws groundwater from a higher location and delivers it to lower agricultural land. During long-term water delivery, the qanat tunnel has experienced different degrees of aging and collapse, which may result in the significant ground settlement and even disasters. This paper developed a two-dimensional laboratory system to investigate the influence of progressive failure on the stability of deeply buried qanat tunnels. The developed system is fully instrumented with a particle image velocimetry (PIV) system and earth pressure and displacement monitoring. A special cylindrical membrane tube is designed and connected to an advanced pressure¿volume controller to simulate the step-wise failure process of the tunnel. Three model tests were conducted on a dry sand considering the buried qanat tunnels at three different depths. Experimental results clearly show the progressive evolution of soil arching effect in the dry sand associated with the progressive failure of the tunnels. The failure of the Qanat ground starts from the vault and develops upwards, which is closely related to the evolution of stress contour at three consecutive stages. Ground surface settlement and volume loss corresponding to three burial depths were compared. A deeply buried qanat tunnel has a small effect on surface settlement. Earth pressure evolution on the 2D plane shows the load redistribution when the qanat collapses. The maximum arch and the initial point of the limit state correspond to a volume loss of 12.5 % and 50 %, respectively. For the collapse of the deep buried qanat tunnel, ground earth pressure evolution can be divided into a stress-increasing region, stress-decreasing region, and no redistribution region. Furthermore, a multi trap-door model considering soil expansion is proposed to describe the progressive failure behavior and its effects.
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2023 |
Chen K, Yuan S, Pan S, Ma J, Liu X, 'Energy-based insight into characterization of shakedown behavior of fully weathered red mudstone', Soils and Foundations, 63 (2023) [C1] Weathered Red mudstone is widely distributed in Sichuan basin. The compacted weathered red mudstone has been used as subgrade fill materials of high-speed railway in southwestern ... [more] Weathered Red mudstone is widely distributed in Sichuan basin. The compacted weathered red mudstone has been used as subgrade fill materials of high-speed railway in southwestern of China. Dynamic responses of such materials under cyclic loading are critical to long-term stability of subgrade. Shakedown concept is widely employed in characterizing the permanent deformation behavior of soils. According to the evolution of axial strain (Werkmeister's theory) or unit dissipated energy (Tao's theory) with loading cycles, the behavior of unbound granular materials can be classified into three categories: plastic shakedown, plastic creep and incremental collapse. However, both theories are more suitable for the unbound granular materials with some limitations when used to separate the plastic creep and incremental collapse behavior. To overcome the limitations of the current theories, 26 cyclic triaxial tests were conducted on a saturated fully weathered red mudstone (SFWRM) to study the evolution of axial strain and unit dissipated energy during cyclic loading. A clear dependency of axial strain, axial strain rate on the unit dissipated energy level under various cyclic stress states were observed. A new criterion which is based on the responses of unit dissipated energy with cyclic stress ratio, was proposed to determine the limit between plastic creep and incremental collapse. Comparing with Werkmeister's criterion and Tao's criterion, the proposed criterion showed a better performance in identifying the incremental collapse behavior of the SFWRM.
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2023 |
Zhang Y, Liu X, Yuan S, Zhang T, Song J, Chen W, 'Probabilistic stability analysis of qanat tunnels in
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2023 |
Pan G, Yuan S, Zheng Y, Tian M, Wang Y, Liu X, 'Experimental investigation on the effect of initial structure on the water retention behavior of Mile clay', Construction and Building Materials, 401 (2023) [C1] Soil structure has strong effect on hydro-mechanical properties of soils, particularly in the case of expansive clays. Along the wetting¿drying path, expansive clays undergo signi... [more] Soil structure has strong effect on hydro-mechanical properties of soils, particularly in the case of expansive clays. Along the wetting¿drying path, expansive clays undergo significant volume changes that can pose serious challenges for infrastructures built on them. Moreover, the hydro-mechanical behaviour of intact, compacted, and reconstituted expansive clay exhibits notable differences. In this study, the effect of natural soil structure of intact Mile expansive clay on water retention behaviour was studied by comparing two states of Mile clay, intact and compacted states. The corresponding water retention behavior along the main wetting and drying paths were analysed and compared. Utilizing scanning electron microscope and mercury intrusion porosimetry tests, the different water retention behaviours observed between intact and compacted Mile clay were further elucidated from a microstructural aspect. It shows that bonding between and within soil aggregates in intact Mile clay constrained volume changes in specimens along the drying and wetting paths. Along these paths, the volume of micropores in intact specimens was consistently larger than that of compacted specimens, resulting in a good water retention behavior, particularly along the main wetting path. Volume changes of intact and compacted specimens were primarily driven by changes in macropore volume. Only when specimens become unsaturated, the changes in micropore volume became significant. At very high suction, the effect of bonding between and within soil aggregates diminished, which was possibly due to the destruction of bonding, resulting in similar water retention properties for intact and compacted specimens.
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2023 |
Chen K, Liu X, Jiang G, Yuan S, Pan S, Yu Z, 'Experimental study on dynamic and dissipated energy behaviors of saturated red mudstone fill materials', Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering, 45 571-579 (2023) [C1] The deformation control of subgrade plays a key role in ensuring the smoothness of the railway. The deformation of subgrade is dependent on the traffic loads and the dynamic behav... [more] The deformation control of subgrade plays a key role in ensuring the smoothness of the railway. The deformation of subgrade is dependent on the traffic loads and the dynamic behavior of subgrade fill materials. A series of drained cyclic triaxial tests are employed to study the dynamic and dissipated energy behaviors of saturated red mudstone fill materials (SRMF), with particular emphasis on the effects of confining pressure and cyclic stress. The results indicate that the permanent axial strain, axial strain rate and equivalent Young¿s modulus are interrelated via the corresponding state boundary surface (SBS). The variation of confining pressure will lead to change in the shape and size of the SBS. The position of dynamic response in the SBS is dependent on the magnitude of cyclic stress. The two-stage dissipated energy behavior is observed. The dissipated energy is first reduced (stage 1) and then reaches its stable state (stage 2) with loading cycles. The permanent axial strain, axial strain rate and equivalent Young¿s modulus are strongly correlated with the dissipated energy, and is also portrayed by their SBS. The amount of the dissipated energy in the SRMF corresponds to the cyclic stress level. When the relative dissipated energy level is less than 20%, the SRMF is said to reach the dynamic stable state. When the relative dissipated energy is between 20% and 60%, the SRMF is named as the dynamically critical state. On the other hand, when the relative dissipated energy is greater than 60%, the long-term stability cannot be finally obtained, and the SRMF goes to the dynamically unstable state.
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2023 |
Wang T, Liu X, Hou Z, Zhang J, Shao Z, Tian S, Hu J, 'Seismic Dynamic Response and Failure Mode of Cracked Bedding Rock Slope', Gongcheng Kexue Yu Jishu/Advanced Engineering Sciences, 55 43-49 (2023) [C1] Cracked bedding rock slopes (CBRSs) are numerous in the southwest mountainous area. The action of earthquakes often causes disasters, such as collapses and landslides. The distrib... [more] Cracked bedding rock slopes (CBRSs) are numerous in the southwest mountainous area. The action of earthquakes often causes disasters, such as collapses and landslides. The distribution law of the structural plane is herein detailed via field research and references to engineering geological data based on a CBRS project in the southwest mountain area. Moreover, the overall stability of the slope is examined through stereographic projection. On this basis, multiple groups of CBRS models were established through discrete-element UDEC, and their dynamic characteristics and failure modes were analyzed by loading EL¿Centro and Kobe waves. Further, the sensitivity of joint parameters to displacement and acceleration responses was studied. The research results demonstrate that the displacement response of the slope first increases and then decreases, and the maximum displacement response of the slope occurs at M4. The PGA amplification coefficient of the slope model clearly demonstrates the elevation amplification effect, and the type of seismic wave affects the PGA response law. The local FFT amplitude drops as the seismic wave crosses the structural plane at the intersection of strong and weak weathering. The CBRS fails under the fracture propagation¿sliding failure mode of the strongly weathered rock mass. According to the sensitivity analysis of joint parameters, the spacing of strong weathered joints has the greatest influence on acceleration amplification, whereas the bedding spacing in weakly weathered rock regions has the most pronounced effect on displacement. The numerical simulation analysis reveals the dynamic response law and failure mode of a CBRS under earthquake, which provides a useful reference for further studying the disaster mechanism and preventing such slope occurrences.
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2023 |
Liu Q, Liu X, Li J, Yuan S, He P, Giacomini A, Buzzi O, 'Dynamic behavior of new anchor cable ribbed rockfall retaining walls on rock shed: Rockfall impact', Proceedings of the Institution of Civil Engineers: Geotechnical Engineering, (2023) [C1] This study investigates the dynamic behavior between a rockfall and a new anchor cable ribbed rockfall retaining walls on a rock shed, which is designed to meet project requiremen... [more] This study investigates the dynamic behavior between a rockfall and a new anchor cable ribbed rockfall retaining walls on a rock shed, which is designed to meet project requirements due to the tremendous space occupation of the protection structure, via numerical simulations by the coupling between PFC3D (discrete element method, DEM) and FLAC3D (finite element method, FEM). In the model, the slope model was imported after the point cloud of the slope was processed. The novel structure is modeled by the finite element method (FEM) through the zone element, while the rockfall and the buffer layer are modeled by the discrete element method (DEM) through the ball element. The dynamic movement of rockfall was traced, and the impact position and velocity were obtained on the structure. The numerical results show that three stages of the rockfall movement were modeled, namely, movement, impact, and stagnation. The rockfall falls on the slope, impacting the buffer layer on the top of the rock shed, before rebounding to the anchored rockfall retaining walls (with a height lower than 2 m). Then, the stress and deflection can be unified and related to the impact velocity of rockfall to examine the stability of the structure. In addition, the rockfall radius is the dominant parameter in the three parameters (rockfall shape, rockfall radius, and impact velocity). While the study focuses on a specific case study, the results provide valuable guidelines for future applications of the proposed combined structure for railway transportation protection.
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2023 |
Danxi S, Xian-feng L, Sheng-yang Y, Gaofeng P, Guanlu J, Hailong W, et al., 'Three-dimensional characterization of cracks in undisturbed Mile expansive soil using X-ray computed tomography', Soils and Foundations, 63 (2023) [C1] The distribution of cracks strongly affects the hydro-mechanical behavior and strength of soil. In order to characterize the distribution of cracks in undisturbed expansive soil, ... [more] The distribution of cracks strongly affects the hydro-mechanical behavior and strength of soil. In order to characterize the distribution of cracks in undisturbed expansive soil, X-ray computed tomography (X-ray CT) tests were carried out for one type of undisturbed expansive soil from Mile City, China. Seven undisturbed specimens retrieved from depths between 1 and 4.7 m were used to study the evolution of cracks along the drying path. The characteristics of the cracks were quantitatively studied by 3D parameters extracted from CT images by commercial software. The test results suggested that, with an increase in suction, the total volume of the cracks gradually increased, and one large crack formed due to the merging of sub-cracks before the shrinkage limit. When the suction was larger than the suction corresponding to the shrinkage limit, degradation of the cracks caused by the collapse of the soil structure was observed. Meanwhile, due to the development of sub-cracks, the crack anisotropy caused by the typically oriented primary cracks decreased along the drying path. Finally, a conceptual model of crack development for undisturbed Mile clay was proposed based on the evolution of crack volume, number, shape, and orientation.
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2022 |
Chen K, Liu XF, Yuan SY, Pan SX, Ma J, Jiang GL, 'Experimental study of accumulative deformation behaviour and shakedown limit of saturated red mudstone fill material', Yantu Lixue/Rock and Soil Mechanics, 43 1261-1268 (2022) [C1] Red mudstone compacted at optimal water content has been verified to be appropriate as fill material of high-speed railway subgrade. But the accumulative deformation behaviour of ... [more] Red mudstone compacted at optimal water content has been verified to be appropriate as fill material of high-speed railway subgrade. But the accumulative deformation behaviour of compacted red mudstone at saturated condition has not been investigated very well. In this study, a series of cyclic triaxial tests was carried out to study the effect of confining pressure and dynamic load on the accumulative deformation of saturated red mudstone fill (SRMF) material. Results indicate that the equivalent Young¿s modulus Eeq decreases rapidly to a stable state with increasing the cyclic number. The stable Eeq is strongly correlated to the stress state, and it increases with increasing the confining pressure and decreases exponentially with increasing the cyclic stress ratio. Based on shakedown theory, three types of accumulative deformation modes, namely, plastic shakedown, plastic creep, and incremental collapse, were identified. The stress state causing the unstable deformation was named as the plastic shakedown limit. The stress state that causes a sudden increase in strain rate was defined as the plastic creep limit. The cyclic stress ratios corresponding to the plastic shakedown and plastic creep limit were smaller than the shear strength at static state, and decreased exponentially as the confining pressure increases. With particular emphasis on the effects of rainfall, the drainage facilities and improved red mudstone fill material were suggested in the design of surface layer of subgrade to enhance their stability.
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2022 |
Liu X, Zhang Y, Yuan S, Chen Z, Chen W, 'Effect of Intersection Angle on the Critical Depth of High-speed Railway Embankment Obliquely Crossing Qanat Culvert', Journal of Railway Engineering Society, 39 26-31 (2022) [C1] Research purposes: During the construction of the subgrade engineering, the disturbance of the underground qanat culvert by the inclined crossing can cause different damage patter... [more] Research purposes: During the construction of the subgrade engineering, the disturbance of the underground qanat culvert by the inclined crossing can cause different damage patterns in the culvert. Therefore, it is necessary to clarify the response of existing qanat culverts under the new high-speed subgrade engineering, to carry out the study of the subgrade engineering load-foundation soil-qanat culvert interaction through three-dimensional numerical simulation, and to determine the stability critical depth corresponding to different intersection angles. Research conclusions:(1) Due to the oblique intersection between the railway and the existing qanat culvert, when the existing qanat culvert crosses over the overlying subgrade, the subgrade surface will experience uneven settlement. (2) The larger the intersection angle between the culvert and the railway, the smaller the range of plastic zone, the smaller the shear strain around the culvert. The criteria for evaluating the critical depth of the qanat culvert can be better used to evaluate the intersection angle to the stability of the high-speed railway embankment oblique crossing qanat. (3) Combining the critical depth evaluation criteria, the stable critical depth change rule of the qanat culvert without support is obtained, that is, when the intersection angle is 0°, 30°, 60° and 90°, the critical depth of the qanat culvert is 14 m, 13 m, 8 m and 7 m. (4) The research results can provide a technical reference for the design of high-speed railways in the qanat region.
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2022 |
Chen K, Liu XF, Yuan SY, Pan SX, Ma J, Jiang GL, 'Shakedown behavior of saturated weathered red mudstone', Soil Dynamics and Earthquake Engineering, 162 (2022) [C1] Red mudstone is widely distributed in the southwest part of China, and it has been used as the fill material in the construction of railway embankment. Shakedown behavior of satur... [more] Red mudstone is widely distributed in the southwest part of China, and it has been used as the fill material in the construction of railway embankment. Shakedown behavior of saturated red mudstone fill material(SRMF) was characterized via a series of drained cyclic triaxial tests. Three types of deformation response were recorded in this study. Strong correlation was observed between deformation response and stress state (confining pressure, cyclic amplitude and cyclic stress ratio). In order to determine the shakedown limit and the creep limit, responses of axial strain, axial strain rate and dissipated energy were used. Especially for the determination of the creep limit, correlation between dissipated energy and cyclic stress ratio was used to overcoming the difficulty encountered in conventional method. Tests results showed that the cyclic stress ratios corresponding to the shakedown and creep limits were lower than the monotonic compression strength. A clear power function was identified to correlate the limits with confining pressure.
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2022 |
Yuan S, Liu X, Wang Y, Delage P, Aimedieu P, Buzzi O, 'X-Ray microtomography of mercury intruded compacted clay: An insight into the geometry of macropores', Applied Clay Science, 227 (2022) [C1] Soil properties, such as wetting collapse behaviour and permeability, are strongly correlated to the soil microstructure. To date, several techniques including mercury intrusion p... [more] Soil properties, such as wetting collapse behaviour and permeability, are strongly correlated to the soil microstructure. To date, several techniques including mercury intrusion porosimetry (MIP), can be used to characterize the microstructure of soil, but all techniques have their own limitations. In this study, the features of mercury that penetrated and has been entrapped in the pore network of the specimens through MIP testing were investigated by X-Ray microtomography (X-µCT), in order to give an insight into the geometry of macropores and possible ink-bottle geometry. Two conditions of water content and density were selected for the compacted Maryland clay. The distribution and geometry features of mercury entrapped in the microstructure after MIP were characterized and pore size distributions were also reconstructed. The results suggest that, for the two conditions studied in this paper, macropores were evenly distributed within the specimens, and most of them with a non-spherical shape, and with aspect ratio (ratio between the maximum and minimum thickness along a given segment) smaller than three. Different dominant entrance pore size of macropore was obtained from MIP and X-µCT, due to the specific experimental protocol used in tests and the effect of ink-bottle geometry. Only the large pore bodies with high aspect ratio were imaged in X-µCT, due to the extrusion of mercury during the process of depressurization and subsequent sample preparation for X- µCT. But entire pore space was accessible in MIP. The difference in dominant entrance pore size was more significant for specimens with lower void ratio due to a more pronounced aspect ratio.
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2022 |
Wang T, Liu X, Zheng L, Tan W, Bai J, Hu Y, 'Research on the model test on vibration isolation effect of typical vibration isolation measures in urban subway', Earthquake Engineering and Engineering Dynamics, 42 119-126 (2022) In order to study the spatial transmission law of vibration waves and the performance of different types of vibration isolation barriers, five sets of model tests were carried out... [more] In order to study the spatial transmission law of vibration waves and the performance of different types of vibration isolation barriers, five sets of model tests were carried out in this paper to obtain the spatial transmission law of vibration waves of different frequencies in red clay foundation. The vibration acceleration levels were used to quantitatively evaluate the vibration isolation effects of typical continuous vibration barriers such as empty trench, sand-filled trench, gravel-filled trench, and concrete wall. The results show that without vibration isolation, the acceleration level decreases with the increase of horizontal distance from the vibration source in the horizontal direction. In the vertical direction, the acceleration level at the top of the model is slightly larger than that at the bottom of the model, and the variation of the acceleration level decreases with the increase of the horizontal distance from the source. At the same measurement point, with the increase of excitation frequency, the vibration acceleration level of soil shows a decaying trend. Various vibration isolation measures, empty trench vibration isolation effect is the best, and sand-filled trench vibration isolation effect is the worst. The order for the performance of the isolation barrier was as follows, empty trench(best), concrete wall, gravel-filled trench, and sand-filled trench(worst). As vibration wave would reflect at the boundary of isolation barrier, this led to the enhancement of soil vibration at the front of isolation barrier. The degree of enhancement of isolation barrier was as follows, gravel-filled trench (strongest), concrete wall, empty trench, and sand-filled trench(smallest).
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2022 |
Chen W, Min S, Chala AT, Zhang Y, Liu X, 'Assessing compaction of existing railway subgrades using dynamic cone penetration testing', Proceedings of the Institution of Civil Engineers: Geotechnical Engineering, 175 439-450 (2022) [C1] Dynamic cone penetration testing has been extensively used in the past for subgrade performance assessment and quality control in road construction practice. However, the method i... [more] Dynamic cone penetration testing has been extensively used in the past for subgrade performance assessment and quality control in road construction practice. However, the method is not commonly employed on high-speed railways. This is due to lack of field data that prove its feasibility as an alternative method for assessing subgrade quality. To mitigate this gap, a series of in situ tests was performed on existing subgrades built with coarse-grained soils at five different sections along the Tehran-Isfahan high-speed railway in Iran. At each subgrade section tested, four parameters for compaction quality control-blow count, degree of compaction, subgrade reaction modulus and dynamic deformation modulus-were determined at nine different depths from subgrade surface. On the basis of the results obtained, a correlation model was developed to relate the traditional quality control parameters of compacted subgrade fill materials with the blow counts. Finally, a simple method using the correlation models established was proposed for assessment of subgrade compaction quality. The method proposed proved to be an alternative approach for evaluating the state of subgrade compaction and also for assessing the subgrade performance of existing railway subgrades.
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2022 |
Pan G, Liu X, Yuan S, Wang Y, Sun D, Feng Y, Jiang G, 'A Field Study on the Arching Behavior of a Geogrid-Reinforced Floating Pile-Supported Embankment', TRANSPORTATION GEOTECHNICS, 37 (2022) [C1]
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2022 |
Pan G, Liu X, Yuan S, Wang Y, Sun D, Jiang G, 'Field Test Study on Bearing Characteristics of Geogrid-reinforced and Pile-supported Embankment in Over-consolidated Expansive Soil', Tiedao Xuebao/Journal of the China Railway Society, 44 131-141 (2022) [C1] In this paper, based on the CFG geogrid-reinforced and pile-supported embankment of the Kunming-Nanning high-speed railway in the expansive soil area, a full-scale field filling t... [more] In this paper, based on the CFG geogrid-reinforced and pile-supported embankment of the Kunming-Nanning high-speed railway in the expansive soil area, a full-scale field filling test was carried out. The evolution characteristics of soil settlement, pile-soil stress ratio, geogrid strain, and foundation reaction force of CFG pile network structure subgrade with 3 types of different pile lengths and 2 types of different pile spacing embankment were monitored and analyzed. The results show that as the load increases, the soil arching effect will undergo the evolution process of primary soil arching-complete soil arching-reinforced soil arching. This soil arching effect is related to the over-consolidation characteristics and stress redistribution of the foundation. The secondary filling process will cause the soil arch coefficient curve of the long piles (S3 and S4) to change from friction piles to end-bearing piles, while this phenomenon is not obvious for short piles (S2). The loading efficiency Ep of the pile increases with the pile length, Ep finally tends to be a stable value of about 80%. In the initial stage of filling, a large instantaneous foundation reaction force will be generated, which will cause the strength reduction effect of the soil between the piles to fluctuate. With the generation of the soil arching effect, it will rapidly decrease and become stable. The stable values are 0.81, 0.56, 0.46, and 0.31, respectively. The strain of the geogrid mainly occurs in the initial stage of filling, which is mainly caused by the differential settlement of the pile and soil during the filling process, and the strain in the second filling process is small, mainly caused by the overall settlement of the composite foundation. Finally, by comparing and analyzing 7 different types of soil arch calculation theories, it is found that considering the influence of foundation reaction force, the soil arch plastic coefficient a and equivalent earth pressure coefficient ß can better predict the development process of soil arch in this area. But the existing theoretical methods can not directly predict the enhanced effect of the soil arch. The research results can provide a reference for the structural design and deformation control of high-speed pile-net structure in similar areas.
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2022 |
Liu X, Yang J, Zhang Y, Yuan S, Gao Z, Chen W, 'Study on Variability Analysis and Probability Distribution of Foundation Soil of Tehran-Isfahan High-speed Railway', Tiedao Xuebao/Journal of the China Railway Society, 44 154-162 (2022) [C1]
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2022 |
Zhang P, Yin ZY, Jin YF, Liu XF, 'Modelling the mechanical behaviour of soils using machine learning algorithms with explicit formulations', Acta Geotechnica, 17 1403-1422 (2022) [C1] This study systematically presents the application of machine learning (ML) algorithms for constructing a constitutive model for soils. A genetic algorithm is integrated with ML a... [more] This study systematically presents the application of machine learning (ML) algorithms for constructing a constitutive model for soils. A genetic algorithm is integrated with ML algorithms to determine the global optimum model, and the k-fold cross-validation method is used to enhance the models¿ robustness. Three typical ML algorithms with formulations explicitly expressed [i.e., back-propagation neural network (BPNN), extreme learning machine (ELM) and evolutionary polynomial regression (EPR)], and two modelling strategies (i.e. total or incremental stress¿strain strategies) are used. A synthetic database is first generated based on a simple constitutive model to objectively evaluate the performance of three ML algorithms and two modelling strategies. Next, the optimum ML algorithm and the well evaluated modelling strategy are applied to experimental tests for examining its robustness. All results indicate that a BPNN-based constitutive model using the incremental stress¿strain strategy performs best in modelling the mechanical behaviour of soils in terms of interpolation and extrapolation abilities, followed by ELM and then EPR.
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2021 |
Yuan S, Liu X, Buzzi O, 'A microstructural perspective on soil collapse', Geotechnique, 71 132-140 (2021) [C1] Soil collapse is a phenomenon triggered by wetting a loaded soil, the structure of which contains large pores. This type of soil response has been studied since the 1970s and mode... [more] Soil collapse is a phenomenon triggered by wetting a loaded soil, the structure of which contains large pores. This type of soil response has been studied since the 1970s and models that can predict its occurrence and magnitude were proposed from the 1990s. In particular, the concept of loading collapse (LC) curves has been developed in the framework of unsaturated soil mechanics and it has been validated using low-reactivity soils. Several publications have highlighted that the microstructure of expansive soils evolves significantly during swelling, a phenomenon that may affect the location of the LC curve. With that perspective, some studies mention a need to shift the LC curves for experimental data and model predictions to agree. This paper brings new insight into the significance of microstructure for the collapse of a reactive soil. A series of tests was conducted to characterise the microstructure of soil specimens compacted under different initial conditions. Then, three pairs of wetting tests under constant load and under controlled suction were conducted in order to identify the zone of onset of collapse. It was found that the conventional LC curves cannot adequately predict the occurrence of collapse. In contrast, analysing the swelling response in the light of microstructural characterisation led to the conclusion that, for Maryland clay, occurrence of collapse can be tracked by the evolution of the void ratio associated to the macro porosity during wetting.
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2021 |
Liu Q, Wang T, Liu XF, Yuan SY, Huang W, He P, Tan W, 'Study on the combination measurement of rockfall embankments and rock shed on steep slopes', Proceedings of the Institution of Civil Engineers: Geotechnical Engineering, 176 388-401 (2021) [C1] With the widespread construction of railways, many mountainous single-line railway yards need to be expanded, and existing protection measures against rockfall are inadequate to p... [more] With the widespread construction of railways, many mountainous single-line railway yards need to be expanded, and existing protection measures against rockfall are inadequate to protect stations and other infrastructure following expansion. Based on the actual engineering background, in this paper the movement trajectory of falling rocks on a high and steep slope is simulated using RocFall software, and the bouncing height, movement speed and impact energy of falling rocks are derived. According to the numerical simulation results, the rockfall protection measure of rockfall drapery systems plus the combination of rockfall embankments and rock sheds is proposed. The structure of a rockfall embankment¿rock shed is a new type of combined protection measure, in which the rockfall embankments are built on top, with the existing rock shed or new portal foundation and top plate working as the lower foundation. This study shows that this new combination structure can resist the impact of falling rocks with a high factor of safety; the effective interception height of rockfall embankments is increased and the problem of rockfall crossing is solved with the construction of rockfall embankments on top of a rock shed or portal foundation.
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2021 |
Yuan S, Liu X, Pan G, Jiang G, 'Compaction behavior of compacted Maryland expansive soil considering micro-structure effect', Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering, 40 2913-2922 (2021) [C1] In order to study the evolution of stress status of expansive clay, a series of compaction tests for ML clay had been carried out. The samples with different initial water content... [more] In order to study the evolution of stress status of expansive clay, a series of compaction tests for ML clay had been carried out. The samples with different initial water contents were compacted via a home-made one-dimensional compaction apparatus. The evolutions of suction and deformation of samples were analyzed during the compaction process. It shows that compression index(Cc) is significantly affected by initial water content. The value of Cc increases with initial water content if the initial water content is smaller than 21.4%, otherwise it keeps almost constant. The initial water content has little effect on the unloading-reloading index(C r). Due to the "mechanical wetting" effect, the matric suction gradually decreases during compaction. During the unloading stage, the matric suction increases significantly. For the sample with same initial water content, the increment of matric suction due to unloading effect increases with the degree of saturation. Based on the post-compaction suction, the compaction plane could be divided into parts: the post-compaction suction is not affected by the degree of saturation of samples, and the post-compaction suction increases with degree of saturation. It also clearly shows that soil water retention curve of sample with constant volume is strongly affected by the void ratio. Based on suction, the degree of saturation, average effective stress, modified suction and void ratio, models for soil water retention curve and compaction curve have been established. The predict of suction and volume evolution during the compaction has been carried out.
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2020 |
Yuan S, Liu X, Romero E, Delage P, Buzzi O, 'Discussion on the separation of macropores and micropores in a compacted expansive clay', Geotechnique Letters, 10 454-460 (2020) [C1]
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2020 |
Wu L, Jiang G, Liu X, 'Analytical and Numerical Analysis of Additional Stress in Foundation of Bridge Approach Embankment', Geotechnical and Geological Engineering, 38 6069-6082 (2020) [C1]
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2020 |
Jin YF, Yin ZY, Zhou WH, Liu X, 'Intelligent model selection with updating parameters during staged excavation using optimization method', Acta Geotechnica, 15 2473-2491 (2020) [C1] Various constitutive models have been proposed, and previous studies focused on identifying parameters of specified models. To develop the smart construction, this paper proposes ... [more] Various constitutive models have been proposed, and previous studies focused on identifying parameters of specified models. To develop the smart construction, this paper proposes a novel optimization-based intelligent model selection procedure in which parameter identification is also performed during staged excavation. To conduct the model selection, a database of seven constitutive models accounting for isotropic or anisotropic yield surface, isotropic or anisotropic elasticity, or small strain stiffness for clayey soils is established, with each model numbered and deemed as one additional parameter for optimization. A newly developed real-coded genetic algorithm is adopted to evaluate the performance of simulation against field measurement. As the process of optimization goes on, the soil model exhibiting good performance during simulation survives from the database and model parameters are also optimized. For each excavation stage, with the selected model and optimized parameters, wall deflection and ground surface settlement of the subsequent unexcavated stage are predicted. The proposed procedure is repeated until the entire excavation is finished. This proposed procedure is applied to a real staged excavation with field data, which demonstrates its effectiveness and efficiency in engineering practice with highlighting the importance of anisotropic elasticity and small strain stiffness in simulating excavation. All results demonstrate that the current study has both academic significance and practical significance in providing an efficient and effective approach of adaptive optimization-based model selection with parameters updating in engineering applications.
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2020 |
Yang J, Yin ZY, Liu XF, Gao FP, 'Numerical analysis for the role of soil properties to the load transfer in clay foundation due to the traffic load of the metro tunnel', Transportation Geotechnics, 23 (2020) [C1] Soil properties play important role to the metro tunnel settlement induced by traffic load of metro operation. Numerical studies on this topic are still rare due to the lack of ac... [more] Soil properties play important role to the metro tunnel settlement induced by traffic load of metro operation. Numerical studies on this topic are still rare due to the lack of accurate dynamic constitutive models of clay. In this study, a new critical state based bounding surface plasticity model for natural structured clays is first developed. It is able to consider the initial and induced anisotropy of natural clay and the structure disturbance to the initial size of yield surface and to the initial adhesive stress by cyclic loading at low-stress levels. The applicability of the present model is evaluated through comparisons between the predicted and the measured results of numerous stress-path tests on Shanghai clay and Vallericca stiff clay. The model is then implemented as a user-defined model in a finite difference code. A typical tunnel in clay is simulated using the implemented model coupled with Biot's consolidation, for which the stress distribution pattern in subsoils around tunnels due to train movement is investigated. The role of the dynamic constitutive model has been highlighted by comparing the simulation results of a static constitutive model and a dynamic constitutive model. The influences of the soil properties such as the anisotropy, structure ratio, and adhesive mean stress have been found significant to the load tranfer.
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2019 |
Yuan S, Buzzi O, Liu X, Vaunat J, 'Swelling behaviour of compacted Maryland clay under different boundary conditions', Geotechnique, 69 514-525 (2019) [C1]
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2019 |
Yuan S, Liu X, Buzzi O, 'Technical aspects of mercury intrusion porosimetry for clays', Environmental Geotechnics, 8 255-263 (2019) [C1] This paper presents a comprehensive and consistent investigation on three technical aspects associated with mercury intrusion porosimetry (MIP) applied to clayey soils: The effect... [more] This paper presents a comprehensive and consistent investigation on three technical aspects associated with mercury intrusion porosimetry (MIP) applied to clayey soils: The effect of intrusion rate, the effect of the freeze-drying method and the influence of sample size. Although a limited number of publications provide recommendations about the MIP technique, the aforementioned effects were largely left unaddressed. This study was performed on four different soils, having different microstructures. In order to obtain a quasi-static condition at the applied pressure, the smallest intrusion rate was suggested to be used in the MIP tests. It was found that the freezing technique does modify the pore size distribution, due to expansion of water on freezing. The more water in the soil specimen, the more pronounced the effect. The specimen size also matters for similar reasons. The outcome of this study provides a technical basis for MIP on clayey soils.
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2019 |
Yuan SY, Liu XF, Buzzi O, 'Effects of soil structure on the permeability of saturated Maryland clay', GEOTECHNIQUE, 69 72-78 (2019) [C1]
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2018 |
Jiang G, Chen W, Liu X, Yuan S, Wu L, Zhang C, 'Field study on swelling-shrinkage response of an expansive soil foundation under high-speed railway embankment loads', SOILS AND FOUNDATIONS, 58 1538-1552 (2018) [C1]
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2018 |
Zhang CL, Jiang GL, Liu XF, Su LJ, 'Centrifuge Modelling and Analysis of Ground Reaction of High-speed Railway Embankments over Medium Compressibility Ground', KSCE Journal of Civil Engineering, 22 4826-4840 (2018) [C1]
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2018 |
Momenzadeh L, Moghtaderi B, Buzzi O, Liu X, Sloan SW, Murch GE, 'The thermal conductivity decomposition of calcite calculated by molecular dynamics simulation', COMPUTATIONAL MATERIALS SCIENCE, 141 170-179 (2018) [C1]
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2018 |
Wu L, Jiang G, Liu X, Xiao H, Sheng D, 'Performance of geogrid-reinforced pile-supported embankments over decomposed granite soil', Proceedings of the Institution of Civil Engineers: Geotechnical Engineering, 171 37-51 (2018) [C1]
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2017 |
Yuan S, Liu X, Buzzi O, 'Calibration of a Coupled Model to Predict the Magnitude of Suction Generated by Osmotic Technique With PES Membranes and Temperature Effect', GEOTECHNICAL TESTING JOURNAL, 40 144-149 (2017) [C1]
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2016 |
Liu X, Zhang C, Yuan S, Fityus S, Sloan SW, Buzzi O, 'Effect of High Temperature on Mineralogy, Microstructure, Shear Stiffness and Tensile Strength of Two Australian Mudstones', Rock Mechanics and Rock Engineering, 49 3513-3524 (2016) [C1] This study aims at providing quality experimental data on the effects of temperature on tensile strength and small strain shear stiffness of two Australian mudstones. The objectiv... [more] This study aims at providing quality experimental data on the effects of temperature on tensile strength and small strain shear stiffness of two Australian mudstones. The objective is to provide multiscale data in view of developing a numerical model that can capture and simulate the complex multiphysics of underground coal fire propagation. Two mudstones were collected in the Hunter Valley, close to a known underground coal fire, referred to as ¿Burning Mountain.¿ The rock specimens were heated to a range of temperatures (maximum of 900¿°C) for 24¿h, and the materials were comprehensively characterized by X-ray diffraction, thermal gravimetric analyses, optical microscopy and scanning electron microscopy. In addition, mercury intrusion porosimetry was used in order to track changes in pore size distribution with temperature. Investigations at microscale were complemented by testing at the macroscale. In particular, the paper focuses on the evolution of the tensile strength and small strain shear stiffness as the materials are subjected to heating treatment. Results show that both parameters evolve in a non-monotonic manner with temperature. The observed mechanical responses are fully explained and corroborated by microstructural observations.
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2016 |
Liu XF, de Carteret R, Buzzi OP, Fityus SG, 'Microstructural effects of environmental salinity on unbound granular road pavement material upon drying', Acta Geotechnica, 11 445-451 (2016) [C1]
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2016 |
Yuan S, Liu X, Sloan SW, Buzzi OP, 'Multi-scale characterization of swelling behaviour of compacted Maryland clay', Acta Geotechnica, 11 789-804 (2016) [C1] This paper presents a comprehensive experimental investigation on time-dependent swelling behaviour at both macroscale and microscale of a natural Australian expansive soil in com... [more] This paper presents a comprehensive experimental investigation on time-dependent swelling behaviour at both macroscale and microscale of a natural Australian expansive soil in compacted state. A number of one-dimensional swelling tests under different vertical pressures, different initial void ratios and initial water contents were performed. The characterization at macroscale was complemented by extensive microstructural investigations through mercury intrusion porosimetry and scanning electron microscope observation on both as-compacted and swollen specimens. The results were discussed at two different scales within a framework of double-porosity, which was finalized by linking the macrostructural¿microstructural strains ratio with secondary swelling/compression coefficients. The multi-scale correlation appears to be largely independent of the specimen initial conditions. The study showed that the secondary swelling and primary swelling are governed by the same factors and that secondary swelling takes place mainly in macropores, of which the change magnitude depends on the level of confinement applied. The microstructural investigations show that swelling is accompanied by significant microfabric changes.
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2016 |
Zhang C, Jiang G, Liu X, Buzzi O, 'Arching in geogrid-reinforced pile-supported embankments over silty clay of medium compressibility: Field data and analytical solution', Computers and Geotechnics, 77 11-25 (2016) [C1] The objective of this study is to improve the understanding of load transfer mechanism of Geogrid-Reinforced Pile-Supported Embankments (GRPS) via a new 3D analytical approach and... [more] The objective of this study is to improve the understanding of load transfer mechanism of Geogrid-Reinforced Pile-Supported Embankments (GRPS) via a new 3D analytical approach and comprehensive field tests. A full-scale embankment was built over a silty clay of medium compressibility as a part of the Liuzhou-to-Nanning High-speed Railway (LNHR) in China. Six sections of the embankment have been heavily instrumented producing comprehensive data of high quality. Field measurements evidence the existence of soil arching, membrane contribution and ground reaction, phenomena that are all contributing to load transfer mechanism. The new 3D analytical arching model accounts for a triangular arrangement of piles and, unlike existing methods, accounts for all relevant components of load transfer mechanisms. In addition, two key parameters were introduced in the model: an elastoplastic state parameter of soil arching (a) and a coefficient of equivalent uniform stress (ß). The former was used to satisfy the load equilibrium in case of partial arching while the latter was adopted to allow possible nonuniform vertical stress acting on the ground surface. The so-called ground reaction method was incorporated in an innovative manner to take into account the reactive support of the subsoil beneath geogrid-reinforced layer when estimating the tension development in the geogrid. Finally, the performance of the proposed model was assessed against several existing models and field measurements. Results showed that the new model presented herein outperforms existing models and satisfactorily predicts both the pile efficiency and tension development within the geogrid.
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2016 |
Liu X, Yuan S, Sieffert Y, Fityus S, Buzzi O, 'Changes in Mineralogy, Microstructure, Compressive Strength and Intrinsic Permeability of Two Sedimentary Rocks Subjected to High-Temperature Heating', Rock Mechanics and Rock Engineering, 49 2985-2998 (2016) [C1] This study falls in the context of underground coal fires where burning coal can elevate the temperature of a rock mass in excess of 1000°. The objective of the research is to exp... [more] This study falls in the context of underground coal fires where burning coal can elevate the temperature of a rock mass in excess of 1000°. The objective of the research is to experimentally characterize the change in mechanical behaviour, mineralogy and microstructural texture of two sedimentary rocks when subjected to temperatures up to 1200¿°C for 24¿h. Specimens of local sandstone and mudstone were comprehensively characterized by X-ray diffraction and thermal-gravimetric analysis. These analyses were complemented by optical microscopy and scanning electron microscopy on polished thin sections. In addition, pore size distributions of these heated rocks were inferred by means of mercury intrusion porosimetry. These results were extended to an estimation of the intrinsic permeability using the Katz¿Thompson model. Investigations at micro scale were followed by mechanical testing (both unconfined and confined compression tests) on cylindrical specimens of heated rocks. Results show that the unconfined compressive strength (UCS) of both rock types tends to increase when the temperatures increases up to 900¿°C, beyond which the UCS tends to slightly decrease. As for the permeability, a clear increase in intrinsic permeability was observed for both rocks. The macroscopic behaviour was found to be fully consistent with the changes observed at micro scale.
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2016 |
Pineda JA, Liu X-F, Sloan SW, 'Effects of sampling in soft clay: a microstructural insight', Geotechnique: international journal of soil mechanics, 66 969-983 (2016) [C1]
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2016 |
Hubert J, Liu XF, Collin F, 'Numerical modeling of the long term behavior of Municipal Solid Waste in a bioreactor landfill', COMPUTERS AND GEOTECHNICS, 72 152-170 (2016) [C1]
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2016 |
Liu X, Hicher P, Muresan B, Saiyouri N, Hicher P-Y, 'Heavy metal retention properties of kaolin and bentonite in a wide range of concentration and different pH conditions', APPLIED CLAY SCIENCE, 119 365-374 (2016) [C1]
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2015 |
Zhang C-L, Jiang G-L, Liu X-F, Wang Z-M, 'Lateral displacement of silty clay under cement-fly ash-gravel pile-supported embankments: Analytical consideration and field evidence', Journal of Central South University, 22 1477-1489 (2015) [C1]
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2015 |
Liu X, Buzzi O, Yuan S, Mendes J, Fityus S, 'Multi-scale characterization of the retention and shrinkage behaviour of four Australian clayey soils.', Canadian Geotechnical Journal, 53 854-870 (2015) [C1]
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2015 |
Yang C, Liu X, Liu X, Yang C, Carter JP, 'Constitutive modelling of Otaniemi soft clay in both natural and reconstituted states', Computers and Geotechnics, 70 83-95 (2015) [C1] A rate-independent anisotropic elastoplastic constitutive model for natural soft clays is proposed, with emphasis on the effects of cementation or structure and fabric anisotropy.... [more] A rate-independent anisotropic elastoplastic constitutive model for natural soft clays is proposed, with emphasis on the effects of cementation or structure and fabric anisotropy. The characteristic non-linear normal compression line for structured soils is described by defining a variable compressibility as a function of plastic straining. No reference to the 'intrinsic' reconstituted state is required. The effect of plastic anisotropy is investigated from virgin constant stress ratio consolidation tests, which provide an accurate description of the equilibrium states of soil fabric. The change of fabric anisotropy is correlated with the change of inclination of the yield and plastic potential surfaces via a pair of improved rotational hardening laws. Experiments on Otaniemi clay samples in both natural and reconstituted states are simulated. Comparisons of numerical predictions with experimental data illustrate the feasibility and advantage of the proposed methodology to describe the mechanical behaviour of natural soft clays.
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2015 |
Zhang C, Jiang G, Liu X, Wang Z, 'Deformation performance of cement-fly ash-gravel pile-supported embankments over silty clay of medium compressibility: a case study', Arabian Journal of Geosciences, 8 4495-4507 (2015) [C1]
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2014 |
Liu X, Buzzi O, 'Use of hand-spray plaster as a coating for soil bulk volume measurement', Geotechnical Testing Journal, 37 (2014) [C1] This paper presents a new coating material [hand-spray plaster (HSP)] used to measure the bulk volume of soil specimens having irregular shapes. The new method has been validated ... [more] This paper presents a new coating material [hand-spray plaster (HSP)] used to measure the bulk volume of soil specimens having irregular shapes. The new method has been validated against two benchmark methods, namely, the wax and plastic bag methods, by conducting swelling and shrinkage tests on intact Maryland clay. The results show that the new method yields similar values of volume but with much reduced data scattering. The HSP method is also far easier to use than the other two methods. Finally, the stiffness of the coating has been measured and its restraining effect has been found to be negligible. Some of the benefits of using the HSP method are: (1) limited fluid retention by the specimen postimmersion for volume measurement, (2) reduced water-intake rate with elimination of cracking upon swelling caused by high-suction gradients, (3) absence of the restraining effect on specimens upon swelling, and (4) accurate determination of the swelling and shrinkage curves with only one specimen per curve. Copyright by ASTM Int'l (all rights reserved).
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2014 |
Buzzi O, Sieffert Y, Mendes J, Liu X, Giacomini A, Seedsman R, 'Strength of an Australian Coal Under Low Confinement', Rock Mechanics and Rock Engineering, 47 2265-2270 (2014) [C1]
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2014 |
de Carteret R, Buzzi O, Fityus S, Liu X, 'Effect of Naturally Occurring Salts on Tensile and Shear Strength of Sealed Granular Road Pavements', JOURNAL OF MATERIALS IN CIVIL ENGINEERING, 26 (2014) [C1]
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2012 |
Liu X, Collin F, Buzzi OP, Sloan SW, 'Numerical modelling of ground temperature evolution as a result of underground coal fire', Australian Geomechanics Journal, 47 27-32 (2012) [C1]
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2012 |
Liu X, Hammad T, Saiyouri N, Hattab M, 'Physical chemical analysis of marine sediment cementation from the Gulf of Guinea', Comptes Rendus - Geoscience, 344 461-470 (2012) [C1]
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2010 |
Li HM, Jiang GL, Liu XF, 'Study of dynamic characteristics of saturated silty soil ground treated by CFG columns', Yantu Lixue/Rock and Soil Mechanics, 31 1550-1554 (2010) A 1:10 scale shaking table model test was conducted by a large-scale laminar shear box; the test mainly researched on cement fly-ash gravel (CFG) column-net composite foundation, ... [more] A 1:10 scale shaking table model test was conducted by a large-scale laminar shear box; the test mainly researched on cement fly-ash gravel (CFG) column-net composite foundation, with the saturated silty soil ground of the Beijing-Shanghai High Speed Railway which was treated by CFG column-net. It has been plot that the amplification coefficient distribution of response acceleration under a series of input acceleration seismic loads, and the relation between the series of input accelerations and its corresponding amplification coefficient of response acceleration. The results show that: (1) at less than 0.101g loading acceleration, the response acceleration scarcely enlarge and its nephogram presents a horizontal type distribution; (2) at 0.161g loading acceleration, as a result of liquefaction of soil between piles, the respone acceleration greatly increase; (3) at 0.210g loading acceleration, the response acceleration increase result from liquefaction of soil between piles and shear break of CFG column; (4) at 0.324g, 0.363g loading acceleration, the integral rigidity of foundation decreases greatly, which reduces its capability of the shock transferred and result in the response acceleraton is less than that at the former loading acceleration; (5) during the course of loading acceleration, amplification effect of response acceleration is obvious in silty soil, but not in clay layer.
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2008 |
Yan D, Jiang GL, Liu XF, Li HM, 'Experimental research on liquefaction behavior of saturated silt for Beijing-Shanghai High-speed Railway', Yantu Lixue/Rock and Soil Mechanics, 29 3337-3341 (2008) The liquefaction for saturated silty foundation under dynamic loading is the important research content in the domain of aseismic design of high-speed railway. To analyze the liqu... [more] The liquefaction for saturated silty foundation under dynamic loading is the important research content in the domain of aseismic design of high-speed railway. To analyze the liquefaction resistance and deformation characteristics before and after reinforcing saturated silty ground of Beijing-Shanghai High-speed Railway, a series of dynamic triaxial tests are carried out under two different densities with three pressure conditions of saturated silt in the laboratory. The increasing law of liquefaction resistant curves under two different dry densities of saturated silt, dynamic intensity and the process of bulit-up pore pressure are got from the test research. It can provide the scientific data to further analyze the liquefaction deformation characteristics before and after reinforcing saturated silty ground.
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2007 |
Jiang G, Liu X, Zhang J, Zhao R, 'Shaking table test of composite foundation reinforcement of saturated silty soil for high speed railway', Frontiers of Architecture and Civil Engineering in China, 1 353-360 (2007) [C1] Three shaking table model tests were conducted with a geometrical scale of 1:10 using a large-scale laminar shear box to investigate the reinforcement effects of compacted gravel ... [more] Three shaking table model tests were conducted with a geometrical scale of 1:10 using a large-scale laminar shear box to investigate the reinforcement effects of compacted gravel column-net composite foundation and cement fly-ash gravel (CFG) column-net composite foundation on the saturated silty soil along the Beijing-Shanghai High Speed Railway. The research results indicate that the increase in excess pore water pressure can be restrained effectively by the compacted gravel column-net composite foundation to improve the anti-liquefaction ability of the ground, and that shear displacement of the ground can be reduced greatly by the compacted gravel column-net and CFG column-net composite foundations to improve the capability of resisting shear displacement of ground. Furthermore, the amplifying of response acceleration, induced by foundation liquefaction, and the settlement of foundation and subgrade can be reduced greatly by the compacted gravel column-net and CFG column-net composite foundations to improve the aseismatic property of the foundation and subgrade. © 2007 Higher Education Press and Springer-Verlag.
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2006 |
Jiang G, Liu X, Zhang J, Zhao R, 'Shaking table test of composite foundation reinforcement of saturated silty soil ground for high speed railway', Xinan Jiaotong Daxue Xuebao/Journal of Southwest Jiaotong University, 41 190-196 (2006) Three shaking table model tests were conducted with a geometrical scale of 1:10 using a large-scale laminar shear box to investigate the reinforcement effects of compacted gravel ... [more] Three shaking table model tests were conducted with a geometrical scale of 1:10 using a large-scale laminar shear box to investigate the reinforcement effects of compacted gravel column-net composite foundation and cement fly-ash gravel (CFG) column-net composite foundation on the saturated silty soil ground along the Beijing-Shanghai high speed railway. The research results indicate that the increase of excess pore water pressure can be restrained effectively by the compacted gravel column-net composite foundation to improve the anti-liquefaction ability of ground, and that shear displacement of ground can be reduced greatly by the compacted gravel column-net and CFG column-net composite foundations to improve the anti-shear displacement ability of ground. Furthermore, the amplifying of response acceleration, induced by foundation liquefaction, and the settlement of foundation and subgrade can be reduced greatly by the compacted gravel column-net and CFG column-net composite foundations to improve the aseismatic property of foundation and subgrade.
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Show 60 more journal articles |
Conference (16 outputs)
Year | Citation | Altmetrics | Link | ||||||||
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2019 |
Pan G, Liu X, Jiang G, Sun D, Tesema CA, Feng Y, 'Swelling-shrinkage deformation of an expansive soil foundation under high speed railway embankment loads: A case study', 7th Asia-Pacific Conference on Unsaturated Soils, AP-UNSAT 2019 (2019) This paper presents a case study of the swelling-shrinkage behaviors of an expansive soil foundation under high-speed railway embankment loads at a test site along Kunming-Nanning... [more] This paper presents a case study of the swelling-shrinkage behaviors of an expansive soil foundation under high-speed railway embankment loads at a test site along Kunming-Nanning High-speed rail line (KNHR). A full-scale field test facility was built for the site-filling test in the expansive soil foundation, of which consist of embankments with two different fill heights (4.88m and 7.49m). All the test embankments were fully instrumented to monitor the ground deformation during the entire filling process. Field test results demonstrated the feasibility of constructing embankments with appropriately designed heights over the expansive soil ground to meet the strict deformation requirements for high-speed railways. Finally, a simple method for estimating the critical filling height of a subgrade was proposed, which protect the top surface of subgrade form swelling-shrinkage behaviors of an expansive soil ground. |
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2019 |
Yuan S, Liu X, Buzzi O, 'Influence of pore water salinity on the compressibility of Maryland clay', Japanese Geotechnical Society Special Publication: 7th Asia-Pacific Conference on Unsaturated Soils, Nagoya, Japan (2019) [E1]
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2019 |
Ou K, Pineda JA, Liu X, Sheng D, 'Osmotic effects on the microstructure of Ashfield shale', Japanese Geotechnical Society Special Publication: 7th Asia-Pacific Conference on Unsaturated Soils, Nagoya, Japan (2019) [E1]
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2017 |
Pineda JA, Liu X, Kelly RB, Suwal L, Sloan SW, 'Modifications in soil fabric due to tube sampling in soft clay', Proceedings of the 19th International Conference on Soil Mechanics and Geotechnical Engineering, Seoul, Korea (2017) [E1]
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2016 |
Yuan S, Liu X, Sloan S, Buzzi O, 'Characterization of the secondary swelling of compacted Maryland clay', 3RD EUROPEAN CONFERENCE ON UNSATURATED SOILS - E-UNSAT 2016, Paris, FRANCE (2016) [E1]
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2016 |
Yuan S, Liu X, Buzzi O, 'Response of different osmotic membranes and calibration of a coupled model capturing the temperature effect for the osmotic method', 3RD EUROPEAN CONFERENCE ON UNSATURATED SOILS - E-UNSAT 2016, Paris, FRANCE (2016) [E1]
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2015 |
Liu X, Buzzi OP, Fityus S, Sieffert Y, 'Mechanical behaviour of an australian mudstone subjected to heating treatment at high-temperatures', 13th ISRM International Congress of Rock Mechanics Proceedings, Montreal, Canada (2015) [E1]
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2015 |
Saiyouri N, Liu X, 'Microstructural approach for heavy metal propagation in saturated clays', Geomechanics from Micro to Macro, Vols I and II, Univ Cambridge, Cambridge, ENGLAND (2015)
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2014 |
Liu XF, Buzzi OP, Vaunat J, 'Influence of stress-volume path on swelling behavior of an expansive clay', Unsaturated Soils: Research and Applications, Sydney (2014) [E1]
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2014 |
Yang C, Yang CS, Liu XF, 'An improved modeling of hydro-mechanical behavior of unsaturated compacted soils', Unsaturated Soils: Research and Applications, London (2014) [E1]
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2012 |
Liu X, Collin F, Buzzi OP, Sloan SW, 'Numerical modelling of ground temperature evolution and soil subsidence as a result of underground coal fire', 11th Australian New Zealand Conference on Geomechanics Conference Proceedings, Melbourne, Australia (2012) [E1]
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2012 |
Liu X, Buzzi OP, 'Experimental characterization of shrinkage behaviour of Australian expansive soils', Unsaturated Soils: Research and Applications, Napoli, Italy (2012) [E1]
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2010 |
Liu XF, Saiyouri N, Hicher PY, 'Influence of heavy metal contaminants on the compressibility of reconstituted kaolinite', Geotechnical Special Publication (2010) [E1] The study aims to investigate the influence of heavy metal contaminants on the compressibility of clays. Two one-dimensional consolidation tests were performed on reconstituted ka... [more] The study aims to investigate the influence of heavy metal contaminants on the compressibility of clays. Two one-dimensional consolidation tests were performed on reconstituted kaolinite samples with two types of pore fluids: distilled water and 2 mM Cu (NO3)2 solution. The influence of the heavy metal contaminants on compressibility (Cc, C s, Cae) was then examined. In order to investigate heavy metal ions interaction with the kaolinte used, a series of batch tests were conducted. In addition, prior to consolidation, the clay samples were tested for their microstructure by using scanning electron microscope observation (SEM) and mercury intrusion pore size distribution measurements (MIP). Furthermore, the permeability coefficient of the specimens can be estimated using Terzaghi's one-dimensional consolidation theory. The first results tend to indicate that the permeability and compressibility of kaolinite were slightly affected when using the diluted Cu (NO3)2 solution. © 2010 ASCE.
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2010 |
Liu X, Saiyouri N, Hicher PY, 'Change of microstructure of clays due to the presence of heavy metal ions in pore water', EPJ Web of Conferences (2010) The compressibility of engineered barrier clays is, to a large extent, controlled by microstructure change due to the presence of chemical ions in clay-water system. This paper ai... [more] The compressibility of engineered barrier clays is, to a large extent, controlled by microstructure change due to the presence of chemical ions in clay-water system. This paper aims to investigate the change of microstructure of clays due to the presence of heavy metal ions in pore water. We use two pure clays (kaolinite and bentonite) in the study. One-dimensional consolidation tests were performed on reconstituted samples, which are prepared with distilled water and three types of heavy metal solutions (Pb(NO3)2, Cu(NO3)2, Zn(NO3)2,). In order to better understand the impact of chemical pore fluid on microstructure of the two clays, following the consolidation test, scanning electron microscope (SEM) observations and mercury intrusion pore size distribution measurements (MIP) were conducted. Due to the measurement range of MIP, which is only allowed to measure the minimal pore size 20 Å, BET method by gas sorption, whose measurement pore size range is from 3.5 Å to 500 Å, is used to measure the micropore size distribution. By this method, specific surface area of the soils can be also determined. It can be employed to demonstrate the difference of creep performance between the soils. Furthermore, a series of batch equilibrium tests were conducted to better understand the physical-chemical interactions between the particles of soils and the heavy metal ions. With the further consideration of the interparticle electrical attractive and repulsive force, an attempt has been made to predict the creep behaviour by using the modified Gouy-Chapman double layer theory. The results of calculation were compared with that of tests. The comparison shows that the prediction of compressibility of the clays according to the modified double diffuse layer theory can be reasonably agreement with the experimental data.
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Preprint (2 outputs)
Year | Citation | Altmetrics | Link | ||
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2023 |
Zhang S, Jiang G, Yuan S, Liu X, Liu Y, 'Performance of Composite Foundations with Different Load Transfer Platform and Substratum Stiffness Over Silty Clay: Centrifuge Modelling (2023)
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2023 |
Chen K, Liu X, Yuan S, Ma J, Chen Y-H, Pineda J, Jiang G-L, 'Effect of Stress State and Stress Path on Small Strain Stiffness of Red Mudstone Fill Material (2023)
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Research Supervision
Number of supervisions
Past Supervision
Year | Level of Study | Research Title | Program | Supervisor Type |
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2017 | PhD | Multi-scale Study of the Hydro-mechanical Behaviour of Maryland Clay | PhD (Civil Eng), College of Engineering, Science and Environment, The University of Newcastle | Co-Supervisor |
Dr Xianfeng Liu
Position
Honorary Associate Professor
Geotechnical group
School of Engineering
College of Engineering, Science and Environment
Contact Details
xianfeng.liu@newcastle.edu.au | |
Phone | (02) 4921 5331 |
Mobile | 0470031851 |
Office
Room | EA205 |
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Building | EA |
Location | Callaghan University Drive Callaghan, NSW 2308 Australia |