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 |
Buzzi O, Ye Y, Vidler A, 'Numerical Study of Damage Accumulation in Brittle Spheres During Repeated Impacts and Development of a Conceptual Model for Rocks', Rock Mechanics and Rock Engineering, (2024) [C1]
Rock fragmentation upon impact during a rockfall event is a very challenging phenomenon to predict. To estimate the likelihood of breakage upon impact, one needs the survival prob... [more]
Rock fragmentation upon impact during a rockfall event is a very challenging phenomenon to predict. To estimate the likelihood of breakage upon impact, one needs the survival probability of the rock. Recently, a survival probability model was proposed and validated for brittle spheres. The model was later extended to irregular shapes under colinear impact with promising preliminary experimental validation. These two models rely on the mechanical properties of the intact material prior to any impact, and as such, these models are only applicable to the very first impact. However, it is very likely for a rock to sustain some damage during a fall and only fragment after several impacts, in which case the survival probability cannot be predicted by the aforementioned models. This numerical study provides new insight into damage accumulation upon multiple impacts in free fall. The study systematically investigates how the work required to achieve failure in quasistatic compression (referred to as work at failure) is affected by prior impacts. Attention is focused on the work at failure because it is one of the key inputs of the survival probability models developed by one of the authors, and tracking its evolution with the number of impacts could allow one to adjust the survival probability with impact history. The simulations show that the governing mechanism for the loss of strength following multiple impacts is the interaction among different damage zones and that¿there exists no unique relationship between damage accumulation and work at failure. The paper concludes with a conceptual model based on the findings of this study and statistical considerations that can be used to predict the evolution of critical work with the impact velocity for different impact scenarios, which in turn can be used to predict the evolution of the¿survival probability of brittle spheres or rocks¿during a fall.
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2024 |
Buzzi O, Jeffery M, Moscato P, Grebogi RB, Haque MN, 'Correction to: Mathematical Modelling of Peak and Residual Shear Strength of Rough Rock Discontinuities Using Continued Fractions (Rock Mechanics and Rock Engineering, (2024), 57, 2, (851-865), 10.1007/s00603-023-03548-0)', Rock Mechanics and Rock Engineering, 57 867-868 (2024)
In the original publication, some corrections were missed. These corrections are listed below: -¿In the abstract: the sentence in bracket should read ¿(defined as the difference i... [more]
In the original publication, some corrections were missed. These corrections are listed below: -¿In the abstract: the sentence in bracket should read ¿(defined as the difference in elevation of two points of the surface over the horizontal distance between these points)¿. -¿In the highlights: the fourth dot point should read: ¿75% of the CFR predictions fall within 20% of the experimental data¿. -¿Section¿2.1: The¿2nd sentence of the second paragraph¿should read ¿Through research, it has been established that only the steepest areas of the surface facing the direction of shearing contribute to the shear response (Grasselli 2001; Grasselli et al. 2002; Jeffery et al. 2022).¿ -¿The last sentence of the paragraph after Eqs.¿(1) and (2) should read ¿See Eqs. (12) and (13) in Appendix for the derivation of s'local_i¿. -¿The following sentence should read ¿NCF is the number of contributing facets on the surface. The total number of triangular facets on the surface depends on the size of the surface and the spatial resolution, as per Appendix¿. -¿In Sect.¿2.3: the total discontinuity area ¿Ao¿ should be noted ¿Atot-o¿, ¿A¿ should be noted ¿Atot¿ in the text and Eq.¿(8). -¿In Fig.¿3: the normal stress should be effective, i.e. s'n. -¿In Sect.¿3: 2nd dot point should read ¿The raw dataset was then reduced to 14,000 data points with a specific filtering process to obtain a dataset with specific values of sdi. This dataset is referred to as the reduced dataset.¿ -¿The first sentence of Sect.¿3.4 should read: ¿To create a reduced-size dataset to guide the training phase of the CFR method, 10% of the enriched dataset (a total of 1400 samples) was selected using the following process: the variance of the enriched dataset was first computed¿. -¿The last sentence of Sect.¿4.3 should read: ¿In 75% of the cases, the discontinuity shear strength can be predicted within ± 20% of the experimental value, which can be considered an excellent result¿. -¿In Table¿6, the unit of standard deviation of gradients sdi should be m/m. -¿In the conclusions, the last¿sentence of the 3rd paragraph¿should read ¿Furthermore, the CFR model predictive capability was tested against experimental data of shear area and shear strength, and 75% of the predictions fell within 20% of experimental values, which confirms the excellent performance of the CFR model¿. -¿In appendix, the notation for number of contributing facets should be NCF, not Ncf. This applies to Eqs.¿(15), (16) and (17) and the unnumbered equation under the caption of Fig.¿9.
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2024 |
Buzzi O, Jeffery M, Moscato P, Grebogi RB, Haque MN, 'Mathematical Modelling of Peak and Residual Shear Strength of Rough Rock Discontinuities Using Continued Fractions', Rock Mechanics and Rock Engineering, 57 851-865 (2024) [C1]
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2023 |
Guccione DE, Giacomini A, Thoeni K, Fityus S, Buzzi O, 'On the Dynamic Fragmentation of Rock-Like Spheres: Insights into Fragment Distribution and Energy Partition', ROCK MECHANICS AND ROCK ENGINEERING, 56 847-873 (2023) [C1]
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Nova |
2023 |
Bertolini I, Gottardi G, Gragnano CG, Buzzi O, 'Calibration of the root water uptake spatial distribution of a young Melaleuca styphelioides, an Australian-native plant, by means of a large-scale apparatus experiment', BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT, 82 (2023) [C1]
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Nova |
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 |
Buzzi O, Guccione DE, 'An Analytical Model to Predict the Survival Probability of Irregular Brittle Rocks in Rockfall under collinear impact', Rock Mechanics and Rock Engineering, 56 4659-4665 (2023) [C1]
The experimental survival probability of one irregular shaped rock was established via 105 drop tests using mortar replicas.The derivation and validation of an analytical model to... [more]
The experimental survival probability of one irregular shaped rock was established via 105 drop tests using mortar replicas.The derivation and validation of an analytical model to predict the survival probability of brittle rocks of irregular shape upon collinear¿impact is presented.The survival probability predicted by the model was found to fall withing 5% of the experimental data with an excellent goodness of fit coefficient (R2 ~ 93%).
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Nova |
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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Nova |
2023 |
Jeffery M, Huang J, Fityus S, Giacomini A, Buzzi O, 'A Large-Scale Application of the Stochastic Approach for Estimating the Shear Strength of Natural Rock Discontinuities', Rock Mechanics and Rock Engineering, 56 6061-6078 (2023) [C1]
Reliable shear strength determination of large in situ discontinuities is still a challenge faced by the rock mechanics field. This is principally due to the limited availability ... [more]
Reliable shear strength determination of large in situ discontinuities is still a challenge faced by the rock mechanics field. This is principally due to the limited availability of surface roughness and morphology information of in situ discontinuities and the unresolved management of the ¿scale effect¿ phenomenon. Recently, a stochastic approach for predicting the shear strength of large-scale discontinuities was established, encompassing random field theory, a semi-analytical shear strength model, and a stochastic analysis framework. A key aspect of the new approach is the application at field scale, thereby minimising or bypassing the scale effect. The approach has been validated at laboratory scale and an initial large-scale deterministic-based validation showed promising results. However, to date, no large-scale experimental-based validation has been undertaken. This paper presents the first rigorous application of the employed semi-analytical shear strength model and the stochastic approach on a 2¿m-by-2¿m discontinuity surface, with comparison of prediction to experimental shear strength data. The shear strength model was found to generally produce peak and residual predictions within a ± 10% relative error range, with good agreement between predicted and observed damage areas. It was observed that, applying the stochastic approach to seed traces with gradient statistics equivalent to that of the surface, produced predictions that closely resemble the experimental results. Whereas, predicting shear strength from different seed traces results in more variability of predictions, with many falling within ± 20% of the experimental data. The predictions of residual shear strength tended to be more accurate than peak shear strength.
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Nova |
2022 |
Jeffery M, Crumpton M, Fityus SG, Huang J, Giacomini A, Buzzi O, 'A Shear Device with Controlled Boundary Conditions for Very Large Nonplanar Rock Discontinuities', GEOTECHNICAL TESTING JOURNAL, 45 725-752 (2022) [C1]
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Nova |
2022 |
Guccione DE, Buzzi O, Thoeni K, Giacomini A, Fityus S, 'Practical considerations for the application of a survival probability model for rockfall', Australian Geomechanics Journal, 57 115-129 (2022) [C1]
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Nova |
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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Nova |
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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Nova |
2021 |
Vidler A, Buzzi O, Fityus S, 'A simple water retention model based on grain size distribution', Applied Sciences (Switzerland), 11 (2021) [C1]
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Nova |
2021 |
Jeffery M, Huang J, Fityus S, Giacomini A, Buzzi O, 'A rigorous multiscale random field approach to generate large scale rough rock surfaces', International Journal of Rock Mechanics and Mining Sciences, 142 (2021) [C1]
Estimating the shear strength of large in situ rock discontinuities is non-trivial because of the multiscale nature of roughness and the fact that only a very limited extent of di... [more]
Estimating the shear strength of large in situ rock discontinuities is non-trivial because of the multiscale nature of roughness and the fact that only a very limited extent of discontinuity morphology is visible along traces. Recently, a novel stochastic method based on random field theory and Monte Carlo semi-analytical estimation of shear strength was proposed. The method was validated at laboratory scale and its application to one large natural surface showed that it has the potential to bypass the scale effect. However, a critical issue was reported by the authors of the study: it was found that the random field approach used could not generate the correct distribution of gradients on the simulated surfaces, which translates into an inaccurate prediction of shear strength. The authors had to manually adjust the input of the model to achieve a satisfactory prediction. This paper presents a new multiscale approach using random field theory, which now allows a rigorous generation of large synthetic 3D surfaces with controlled distribution of asperity heights and gradients from the profile of a 2D fracture trace (as might be visible in a rock face) referred to as a seed trace. Each seed trace is first decomposed into three daughter profiles corresponding to three levels of roughness. The statistics of each daughter profile form the input of the random field model at each scale level, allowing synthetic daughter surfaces to be created at each scale level. The synthetic daughter surfaces are then superimposed to obtain a composite rough surface comprising three levels of roughness. The approach was successfully validated with 25 input seed traces, coming from 5 different natural surfaces. This rigorous multiscale approach is essential to apply the stochastic method that was recently developed to predict the shear strength of large in situ discontinuities.
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Nova |
2021 |
Guccione DE, Thoeni K, Fityus S, Nader F, Giacomini A, Buzzi O, 'An Experimental Setup to Study the Fragmentation of Rocks Upon Impact', Rock Mechanics and Rock Engineering, 54 4201-4223 (2021) [C1]
Rockfall is a natural hazard that needs to be rigorously managed along all the major road and railways transport networks by identifying the most appropriate mitigation measures. ... [more]
Rockfall is a natural hazard that needs to be rigorously managed along all the major road and railways transport networks by identifying the most appropriate mitigation measures. There has been significant progress in rockfall modelling and rockfall protection systems in recent years but there remains one aspect that is not very well understood and quite challenging to account for in the design of rockfall protection structures, namely the fragmentation of falling blocks upon impact. Rocks often break up upon impact, which leads to a change in size, shape and energy of falling blocks, parameters that affect the design of the protective structures. Before being able to incorporate fragmentation into predictive trajectory models, it is required to better understand the fragmentation process and its likely outcome (number, volume of fragments and their trajectories). To that aim, an innovative experimental setup was developed at the University of Newcastle (Australia) to study rock fragmentation upon impact. The setup was designed to perform controlled vertical drop tests and record the following impact parameters: impact force, impulse, impact duration, velocities (of the block before impact and its fragment after impact) and all components of energy, pre and post impact. Six views (four high-speed cameras and two mirrors) are used for an accurate reconstruction of the 3D trajectory of blocks and fragments, in translation and rotation. This paper presents the validation of the setup via two series of drop tests using mortar spheres. Attention was focused on the evaluation of impact force and impulse from load cells placed under the impacted surface, tracking of translational and rotational velocity and the computation of total kinetic energy (before and after impact) and all components of energy dissipation. The results confirm that the experimental setup and the approach developed can be used to obtain impact force, impulse and to compute the energy balance during the impact and fragmentation and conduct advanced fragmentation testing.
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Nova |
2021 |
Guccione DE, Buzzi O, Thoeni K, Fityus S, Giacomini A, 'Predicting the fragmentation survival probability of brittle spheres upon impact from statistical distribution of material properties', International Journal of Rock Mechanics and Mining Sciences, 142 (2021) [C1]
Fragmentation of rocks upon impact during rockfall is a phenomenon that is poorly understood, scarcely researched and difficult to predict. However, to adequately predict the outc... [more]
Fragmentation of rocks upon impact during rockfall is a phenomenon that is poorly understood, scarcely researched and difficult to predict. However, to adequately predict the outcomes of rockfall events, it is essential to know whether a given block is likely to fragment given the impact conditions and what will be the outcome of the fragmentation process; that is, the number, size and trajectory of fragments. To date, there is no model or data that can be used to fully answer these questions. This paper presents the first theoretical model that can predict the fragmentation survival probability of brittle spherical blocks upon dynamic impact (i.e. drop tests) from the statistical distribution of material properties, determined from a range of standard quasi-static tests. Considering that survival probabilities tend to follow a Weibull distribution, the model focuses on predicting the two Weibull parameters, commonly known as the shape parameter (m) and the scale parameter (here, the critical kinetic energy). The model is based on theoretically-derived conversion factors used to turn the critical work required to fail disc samples in quasi-static indirect tension into the critical kinetic energy to cause failure of spheres at impact in drop tests. The mechanistic conversion factors specifically account for the shape and size of the specimens tested and the increase of strength under dynamic loading (strain rate effect). Three series of drop tests were conducted (on spheres of three different diameters) and complemented by extensive material characterisation testing in order to validate the novel predictive model. The variability of material properties was characterised, and it was found that the material strength found by the characterisation tests generally follows a Weibull form, but the survival probability distribution of the drop tests seems to be linear. The predicted conversion factors were first compared against their experimental counterparts before validating the prediction of survival probability of the spheres upon dynamic impact (in drop tests). It was found that it is possible to predict the survival probability of artificial rock of three different diameters (50 mm, 75 mm, 100 mm) and two different strengths upon impact solely from the statistical information coming from Brazilian tests and with an average relative error of less than 9%.
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Nova |
2021 |
Vidler A, Buzzi O, Fityus S, 'The Significance of Hydrophobicity for the Water Retention Properties of Sand and Coal', APPLIED SCIENCES-BASEL, 11 (2021) [C1]
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Nova |
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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Nova |
2020 |
Bertrand F, Buzzi O, Bésuelle P, Collin F, 'Hydro-mechanical modelling of multiphase flowin naturally fractured coalbed using a multiscale approach', Journal of Natural Gas Science and Engineering, 78 (2020) [C1]
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Nova |
2020 |
Tahmasbi S, Giacomini A, Wendeler C, Buzzi O, 'Towards a novel and efficient method to determine the failure energy of rockfall chain-link meshes', COMPUTERS AND GEOTECHNICS, 119 (2020) [C1]
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Nova |
2020 |
Ye Y, Thoeni K, Zeng Y, Buzzi O, Giacomini A, 'Numerical Investigation of the Fragmentation Process in Marble Spheres Upon Dynamic Impact', Rock Mechanics and Rock Engineering, 53 1287-1304 (2020) [C1]
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Nova |
2020 |
Guccione DE, Thoeni K, Giacomini A, Buzzi O, Fityus S, 'Efficient Multi-View 3D Tracking Of Arbitrary Rock Fragments Upon Impact', ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLIII-B2-2020 589-596 (2020) [C1]
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Nova |
2019 |
Tahmasbi S, Giacomini A, Wendeler C, Buzzi O, 'On the Computational Efficiency of the Hybrid Approach in Numerical Simulation of Rockall Flexible Chain-Link Mesh', Rock Mechanics and Rock Engineering, 52 3849-3866 (2019) [C1]
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Nova |
2019 |
Zhang C, Jiang G, Buzzi O, Su L, 'Full-scale model testing on the dynamic behaviour of weathered red mudstone subgrade under railway cyclic loading', Soils and Foundations, 59 296-315 (2019) [C1]
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Nova |
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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Nova |
2019 |
Bertrand F, Buzzi O, Collin F, 'Cleat-scale modelling of the coal permeability evolution due to sorption-induced strain', International Journal of Coal Geology, 216 (2019) [C1]
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Nova |
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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Nova |
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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Nova |
2019 |
Ye Y, Thoeni K, Yawu Z, Buzzi O, Giacomini A, 'A novel 3D clumped particle method to simulate the complex mechanical behavior of rock', International Journal of Rock Mechanics and Minings Sciences, (2019) [C1]
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Nova |
2018 |
Buzzi O, Casagrande D, 'A step towards the end of the scale effect conundrum when predicting the shear strength of large in situ discontinuities', International Journal of Rock Mechanics and Mining Sciences, 105 210-219 (2018) [C1]
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Nova |
2018 |
Casagrande D, Buzzi O, Giacomini A, Lambert C, Fenton G, 'A New Stochastic Approach to Predict Peak and Residual Shear Strength of Natural Rock Discontinuities', ROCK MECHANICS AND ROCK ENGINEERING, 51 69-99 (2018) [C1]
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Nova |
2018 |
Mentani A, Govoni L, Giacomini A, Gottardi G, Buzzi O, 'An Equivalent Continuum Approach to Efficiently Model the Response of Steel Wire Meshes to Rockfall Impacts', Rock Mechanics and Rock Engineering, 51 2825-2838 (2018) [C1]
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Nova |
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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Nova |
2018 |
Rocchi I, Gragnano CG, Govoni L, Mentani A, Bittelli M, Castiglione P, et al., 'A new technique for deep in situ measurements of soil water retention behaviour', Geotechnical Research, 5 3-12 (2018) [C1]
In situ measurements of soil suction and water content in deep soil layers still represent an experimental challenge. Mostly developed within agriculture-related disciplines, fiel... [more]
In situ measurements of soil suction and water content in deep soil layers still represent an experimental challenge. Mostly developed within agriculture-related disciplines, field techniques for the identification of soil retention behaviour have been so far employed in the geotechnical context to monitor shallow landslides and seasonal volume changes beneath shallow foundations, within the most superficial ground strata. In this paper, a novel installation technique is presented, discussed and assessed, which allows extension of the use of commercially available low-cost and low-maintenance instruments to characterise deep soil layers. Multi-depth installations have been successfully carried out using two different sensor types to measure the soil suction and water content up to 7 m from the soil surface. Preliminary laboratory investigations were also shown to provide a reasonable benchmark to the field data. The results of this study offer a convenient starting point to accommodate important geotechnical works such as river and road embankments in the traditional monitoring of unsaturated soil variables.
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Nova |
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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Nova |
2017 |
Buzzi O, Yuan S, Routley B, 'Development and Validation of a New Near-Infrared Sensor to Measure Polyethylene Glycol (PEG) Concentration in Water', SENSORS, 17 (2017) [C1]
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Nova |
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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Nova |
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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Nova |
2016 |
Mentani A, Giacomini A, Buzzi O, Govoni L, Gottardi G, Fityus S, 'Numerical Modelling of a Low-Energy Rockfall Barrier: New Insight into the Bullet Effect', Rock Mechanics and Rock Engineering, 49 1247-1262 (2016) [C1]
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Nova |
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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Nova |
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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Nova |
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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Nova |
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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Nova |
2015 |
Buzzi O, Leonarduzzi E, Krummenacher B, Volkwein A, Giacomini A, 'Performance of High Strength Rock Fall Meshes: Effect of Block Size and Mesh Geometry', Rock Mechanics and Rock Engineering, 48 1221-1231 (2015) [C1]
In rockfall science, the bullet effect refers to the perforation of a rockfall mesh by a small block traveling at high speed. To date, there is still no comprehensive experimental... [more]
In rockfall science, the bullet effect refers to the perforation of a rockfall mesh by a small block traveling at high speed. To date, there is still no comprehensive experimental data set investigating the underlying mechanisms of such effect. The bullet effect illustrates the fact that the capacity of a rockfall mesh depends on the size and speed of the impacting block. This paper presents the results of an experimental study on the effect of block size and mesh geometry (aperture and wire diameter) on the mesh performance. The results clearly show that the amount of energy required to perforate the mesh drops as the blocks get smaller. They also suggest that the mesh performance reaches a maximum and reduces to zero when the mesh cannot sustain the static load imposed by very large blocks. The outcome of the first series validates an analytical model for mesh perforation, making it the first simple model capturing the bullet effect. A second series of tests focused on the effect of mesh geometry and it was found that decreasing the mesh aperture by 19¿% improves the performance by 50¿% while only an extra 30¿% could be gained by increasing the wire diameter by 33¿%. The outcomes of the second series were used to discuss and redefine a dimensionless geometrical parameter G* and to validate a simple power type equation relating the mesh characteristics and the mesh performance.
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Nova |
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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Nova |
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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Nova |
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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Nova |
2014 |
Sieffert Y, Buzzi O, Collin F, 'Numerical study of shear band instability and effect of cavitation on the response of a specimen under undrained biaxial loading', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, 51 1686-1696 (2014) [C1]
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2013 |
Mendes J, Buzzi O, 'New insight into cavitation mechanisms in high-capacity tensiometers based on high-speed photography', Canadian Geotechnical Journal, 50 550-556 (2013) [C1]
The high-capacity tensiometer developed by Ridley and Burland in 1993 is a milestone in experimental unsaturated soil mechanics. This device, which relies on development of tensio... [more]
The high-capacity tensiometer developed by Ridley and Burland in 1993 is a milestone in experimental unsaturated soil mechanics. This device, which relies on development of tension in an enclosed water body, permits direct measurement of negative water potential. Many tensiometers have been built since 1993, all being based on the same principle although the design may differ slightly from the original. In particular, the common characteristic is a very small water reservoir that is believed to be the location of bubble nucleation, a phenomenon referred to as cavitation that impedes the sensor from functioning properly. Many have studied cavitation and different explanations or cavitation mechanisms have been proposed. However, all the considerations put forward were derived without being able to capture what happened inside the water reservoir at cavitation. This is now achieved with the new tensiometer specifically designed to "see" inside the water reservoir during suction measurement. For the first time, cavitation has been captured via high-speed photography and the mechanisms of cavitation can be explained using physical evidence. The first outcome is that it is possible for a high-capacity tensiometer to function to its full range with a large water reservoir. Then, the analysis of high-speed photographs reveals that the bubbles triggering cavitation are nucleated in the ceramic and make their way to the water reservoir. Cavitation occurs only when the air phase reaches the water reservoir.
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Nova |
2013 |
Spadari M, Kardani M, De Carteret R, Giacomini A, Buzzi O, Fityus S, Sloan SW, 'Statistical evaluation of rockfall energy ranges for different geological settings of New South Wales, Australia', ENGINEERING GEOLOGY, 158 57-65 (2013) [C1]
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Nova |
2013 |
Fityus SG, Giacomini A, Buzzi O, 'The significance of geology for the morphology of potentially unstable rocks', Engineering Geology, 162 43-52 (2013) [C1]
From a consideration of the concepts of geological weathering and structure, it can be expected that rockfall hazards should be characteristically different in different geologica... [more]
From a consideration of the concepts of geological weathering and structure, it can be expected that rockfall hazards should be characteristically different in different geological environments. This paper tests this idea by looking at the geometric characteristics of rock fragments formed on natural slopes in four different geological environments in Eastern Australia, where rockfall phenomena are often characterised by rolling of pre-detached debris. By measuring the three principle dimensions and making a systematic assessment of the shape characteristics of samples of rock debris in significant geological environments, it is found that the distributions of size and shape for the surface debris are statistically different. From the results, it is shown that the size and shape of debris is directly controlled by the rock type, its weathering characteristics and the structure of the parent rock mass. The severity of rockfall hazards is shown to be relatively lower in areas of Tertiary basalt, as the size of rolling fragments is limited by closely spaced fracturing inherited from its formation and the tendency to deteriorate further as it weathers deeply and rapidly. It is also lower in areas of Palaeozoic volcanics, since these tend to produce relatively angular fragments with higher proportions of fragments that are inherently more resistant to rolling. By contrast, thickly bedded sandstones form larger blocks with a larger proportion of shapes that are more prone to rolling. The size distribution of fragments is shown to be well approximated by a log-normal statistical distribution, and using the data provided in this study, it is possible to generate the size and shape data needed to undertake a stochastic assessment of rockfall trajectories in different geological environments. © 2013.
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Nova |
2013 |
De Carteret R, Buzzi O, Fityus S, 'Installation, calibration, and application of dielectric sensors in laboratory studies of compacted unsaturated granular materials', Geotechnical Testing Journal, 36 (2013) [C1]
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Nova |
2013 |
Hambleton JP, Buzzi O, Giacomini A, Spadari M, Sloan SW, 'Perforation of Flexible Rockfall Barriers by Normal Block Impact', ROCK MECHANICS AND ROCK ENGINEERING, 46 515-526 (2013) [C1]
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Nova |
2013 |
Buzzi O, Spadari M, Giacomini A, Fityus S, Sloan SW, 'Experimental Testing of Rockfall Barriers Designed for the Low Range of Impact Energy', ROCK MECHANICS AND ROCK ENGINEERING, 46 701-712 (2013) [C1]
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Nova |
2012 |
Russell AR, Buzzi OP, 'A fractal basis for soil-water characteristics curves with hydraulic hysteresis', Geotechnique, 62 269-274 (2012) [C1]
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Nova |
2012 |
Buzzi OP, Giacomini A, Spadari M, 'Laboratory investigation on high values of restitution coefficients', Rock Mechanics and Rock Engineering, 45 35-43 (2012) [C1]
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Nova |
2012 |
Spadari M, Giacomini A, Buzzi OP, Hambleton JP, 'Prediction of the bullet effect for rockfall barriers: A scaling approach', Rock Mechanics and Rock Engineering, 45 131-144 (2012) [C1]
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Nova |
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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Nova |
2012 |
Buzzi OP, Grimes SB, Rolls AC, 'Writing for the discipline in the discipline?', Teaching in Higher Education, 17 479-484 (2012) [C1]
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Nova |
2012 |
Spadari M, Giacomini A, Buzzi OP, Fityus SG, Giani GP, 'In situ rockfall testing in New South Wales, Australia', International Journal of Rock Mechanics and Mining Sciences, 49 84-93 (2012) [C1]
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Nova |
2011 |
Buzzi OP, Giacomini A, Fityus SG, 'Towards a dimensionless description of soil swelling behaviour', Geotechnique, 61 271-277 (2011) [C1]
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Nova |
2010 |
Buzzi OP, 'On the use of dimensional analysis to predict swelling strain', Engineering Geology, 116 149-156 (2010) [C1]
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Nova |
2010 |
Buzzi OP, Fityus SG, Sloan SW, 'Use of expanding polyurethane resin to remediate expansive soil foundations', Canadian Geotechnical Journal, 47 623-634 (2010) [C1]
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Nova |
2010 |
Lambert C, Buzzi OP, Giacomini A, 'Influence of calcium leaching on the mechanical behavior of a rock-mortar interface: A DEM analysis', Computers and Geotechnics, 37 258-266 (2010) [C1]
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Nova |
2009 |
Fityus SG, Buzzi OP, 'The place of expansive clays in the framework of unsaturated soil mechanics', Applied Clay Science, 43 150-155 (2009) [C1]
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Nova |
2009 |
Narsilio GA, Buzzi OP, Fityus SG, Yun TS, Smith DW, 'Upscaling of Navier-Stokes equations in porous media: Theoretical, numerical and experimental approach', Computers and Geotechnics, 36 1200-1206 (2009) [C1]
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Nova |
2009 |
Al-Tarawneh KK, Buzzi OP, Krabbenhoft K, Lyamin AV, Sloan SW, 'An indirect approach for correlation of permeability and diffusion coefficients', Diffusion and Defect Data: Pt A. Defect and Diffusion Forum, 283-286 504-514 (2009) [C1]
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Nova |
2009 |
Al-Tarawneh KK, Buzzi OP, Krabbenhoft K, Lyamin AV, 'Discussion of the Paper 'Experimental Investigation into Concentration-Dependent Chloride Diffusivity in Glass Beads and Fine Sand' by K. Prabhakaran Nair, A. Praveen, and S. Chandrakaran', Journal of Porous Media, 12 289-291 (2009) [C3]
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Nova |
2009 |
Giacomini A, Buzzi OP, Renard B, Giani GP, 'Experimental studies on fragmentation of rock falls on impact with rock surfaces', International Journal of Rock Mechanics and Mining Sciences, 46 708-715 (2009) [C1]
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Nova |
2008 |
Giacomini A, Buzzi OP, Ferraro AM, Migliazza M, Giani GP, 'Numerical study of flow anisotropy within a single natural rock joint', International Journal of Rock Mechanics and Mining Sciences, 45 47-58 (2008) [C1]
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Nova |
2008 |
Buzzi OP, Pedroso DM, Giacomini A, 'Caveats on the implementation of the generalized material point method', Computer Modeling in Engineering & Sciences, 31 85-106 (2008) [C1]
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Nova |
2008 |
Lopez P, Thoraval A, Buzzi OP, Rahmani I, Boulon M, 'Advances in constitutive modeling of jointed rock hydro mechanical interactions at laboratory scale', Studia Geotechnica et Mechanica, 30 223-233 (2008) [C2] |
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Nova |
2008 |
Buzzi OP, Fityus SG, Sasaki Y, Sloan SW, 'Structure and properties of expanding polyurethane foam in the context of foundation remediation in expansive soil', Mechanics of Materials, 40 1012-1021 (2008) [C1]
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Nova |
2008 |
Buzzi OP, Boulon M, Herve M, Su K, 'Leaching of rock-concrete interfaces', Rock Mechanics and Rock Engineering, 41 445-466 (2008) [C1]
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Nova |
2008 |
Buzzi O, Boulon M, Deleruyelle F, Besnus F, 'Hydromechanical behaviour of rock-bentonite interfaces under compression', Rock Mechanics and Rock Engineering, 41 343-371 (2008) [C1]
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2008 |
Fityus SG, Buzzi OP, 'On the use of the Thornthwaite Moisture Index to infer depths of seasonal moisture change', Australian Geomechanics, 43 43-54 (2008) [C1]
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Nova |
2007 |
Buzzi O, Hans J, Boulon M, Deleruyelle F, Besnus F, 'Hydromechanical study of rock-mortar interfaces', Physics and Chemistry of the Earth, 32 820-831 (2007) [C1]
Hydromechanical compression tests have been performed on rock-mortar interfaces representing the contact between a host rock and a concrete bulkhead within an underground nuclear ... [more]
Hydromechanical compression tests have been performed on rock-mortar interfaces representing the contact between a host rock and a concrete bulkhead within an underground nuclear waste repository. The rock used in the tests is a Toarcian argillite. Most published studies concerning rock-concrete interfaces involve concrete-concrete contacts in which rock replicas are used instead of real rock samples. As a result, the effect of rock features, such as bedding planes and changes of the rock interface zone, on the hydromechanical behaviour of the interface cannot be investigated. The tests discussed in this paper demonstrate that the mechanical response is not affected when changing the parameters of the samples even not mismatching both walls. On the contrary, an initial monitored lateral displacement modifies the hydromechanical behaviour by limiting the interface ability to be hydraulically closed. The latter ability has been quantified by a simple evolution law and the difference of behaviour between the two kinds of samples has been confirmed. The analysis led to determine the hydraulic aperture shows that the values obtained are much lower to the classical values available in the literature. Finally, the application of the experimental results to the confinement by a bulkhead showed the localization of the flow within the interface. © 2006 Elsevier Ltd. All rights reserved.
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2003 |
Jafari MK, Amini Hosseini K, Pellet F, Boulon M, Buzzi O, 'Evaluation of shear strength of rock joints subjected to cyclic loading', Soil Dynamics and Earthquake Engineering, 23 619-630 (2003) [C1]
Variation of the shear strength of rock joints due to cyclic loadings is studied in the present paper. Identical joint surfaces were prepared using a developed moulding method wit... [more]
Variation of the shear strength of rock joints due to cyclic loadings is studied in the present paper. Identical joint surfaces were prepared using a developed moulding method with special mortar and shear tests were performed on these samples under both static and cyclic loading conditions. Different levels of shear displacement were applied on the samples to study joint behaviour before and during considerable relative shear displacement. It was found that the shear strength of joints is related to rate of displacement (shearing velocity), number of loading cycles and stress amplitude. Finally, based on the experimental results, mathematical models were developed for evaluation of shear strength in cyclic loading conditions. © 2003 Elsevier Ltd. All rights reserved.
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