2023 |
Goodall SJ, Merifield RS, 'WORKING PLATFORMS AND BEARING CAPACITY ASSESSMENTS OF SAND OVERLYING CLAY USING FINITE ELEMENT LIMIT ANALYSIS', Australian Geomechanics Journal, 58 117-139 (2023) [C1]
The bearing capacity of shallow foundations on layered soils is typically based on empirical models assuming a strip footing. Shape factors are then applied to the strip footing s... [more]
The bearing capacity of shallow foundations on layered soils is typically based on empirical models assuming a strip footing. Shape factors are then applied to the strip footing solution to account for the specific geometry of the foundation being considered. A common practical application of this methodology is when the ultimate bearing capacity of a granular working platform constructed over a clay subgrade is estimated using the Working Platforms for Tracked Plant BRE-470 guideline. Previous studies using finite element limit analysis have been undertaken to examine a strip footing on a layered soil and how the resulting bearing capacity compares to that derived from BRE-470. This paper presents an extension of previous work by the authors using finite element limit analysis to investigate the three-dimensional influence on the bearing capacity of square and rectangular footings on sand over clay. The finite element limit analysis solutions are used to produce charts to assist designers with estimating the ultimate bearing capacity of granular working platforms overlying clay. The paper also aims to highlight some important considerations when adopting the BRE-470 guideline to design granular working platforms overlying clay.
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2021 |
Goodall SJ, Merifield RS, 'PILE DESIGN FOR SOLAR FARMS AND REACTIVE CLAY SITES IN AUSTRALIA', Australian Geomechanics Journal, 56 87-103 (2021) [C1]
There are many geotechnical aspects that require consideration during the design of solar farms. One key consideration, which is a major cost driver for these developments, is the... [more]
There are many geotechnical aspects that require consideration during the design of solar farms. One key consideration, which is a major cost driver for these developments, is the design of the pile foundations supporting the solar arrays. The number of piles is often in the order of tens to hundreds of thousands and contributes to a significant portion of the capital cost of the project. The uptake of commercial scale solar is in its infancy in Australia with the first commercial size farm only commencing operation in late 2012. Consequently, we have limited local case studies for lightly loaded piles installed in reactive clay subjected to wetting and drying cycles on which to base a rational design methodology. Methods are available to analyse this type of problem. However, many are based on simplified assumptions, limited data sets, or can be difficult to apply in practice. Furthermore, some of the available methods rely on laboratory tests, such as swell pressure measurements, of which the results can be highly variable and difficult to rationalise, or insitu tests that are difficult to undertake in engineering practice. This paper provides an overview of the current state of practice in Australia for designing piles supporting solar arrays to resist expansive soil movements and presents some preliminary design charts developed using finite element analysis to assist designers with estimating the vertical pile movements and loads in piles associated with reactive ground movements.
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2021 |
Merifield RS, Goodall SJ, McFarlane SA, 'Finite element modelling to predict the settlement of pile groups founded above compressible layers', Computers and Geotechnics, 134 (2021) [C1]
It is widely accepted that the presence of compressible layers beneath pile groups can substantially increase the settlement of a pile group. Furthermore, as the size of the pile ... [more]
It is widely accepted that the presence of compressible layers beneath pile groups can substantially increase the settlement of a pile group. Furthermore, as the size of the pile group increases this effect is magnified and further complicated by the load distribution across the pile group. A number of simplified methods, such as the equivalent raft or equivalent pier method, are often employed to estimate the settlement of pile groups founded over a compressible layer, however, such methods can lead to both overly conservative and un-conservative results and large variations in results between methods. More recent methods have explored the use of power law functions or energy principles to analyse piles and pile groups in non-homogeneous soil conditions, however, these methods can be difficult to apply in practice. With the availability of modern computers and the advancement of commercially available numerical analyses packages, it is now possible to use the finite element method to analyse pile groups overlying compressible soil layers in order to better understand this problem. This technical note presents some initial results and associated design charts based on the finite element method to provide preliminary estimates of settlement of pile groups overlying compressible layers. Some dimensionless design charts are provided for a range of commonly encountered geotechnical conditions and pile group geometries.
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Nova |
2015 |
Qian ZG, Li AJ, Merifield RS, Lyamin AV, 'Slope Stability Charts for Two-Layered Purely Cohesive Soils Based on Finite-Element Limit Analysis Methods', INTERNATIONAL JOURNAL OF GEOMECHANICS, 15 (2015) [C1]
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Nova |
2014 |
Gaudin C, O'Loughlin CD, Randolph MF, Cassidy MJ, Wang D, Tian Y, et al., 'Advances in offshore and onshore anchoring solutions', Australian Geomechanics, 49 59-71 (2014) [C1]
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Nova |
2014 |
Yu SB, Merifield RS, Lyamin AV, Fu XD, 'Kinematic limit analysis of pullout capacity for plate anchors in sandy slopes', Structural Engineering and Mechanics, 51 565-579 (2014) [C1]
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Nova |
2014 |
Suchowerska AM, Carter JP, Merifield RS, 'Horizontal stress under supercritical longwall panels', International Journal of Rock Mechanics and Mining Sciences, 70 240-251 (2014) [C1]
This study identifies the relative magnitude of horizontal stress change below a series of parallel longwall panels as a consequence of multi-seam mining. The investigation method... [more]
This study identifies the relative magnitude of horizontal stress change below a series of parallel longwall panels as a consequence of multi-seam mining. The investigation method yields an upper bound to the horizontal stress change by assuming that the fractured and caved overburden above the supercritical longwall panels is not able to support any lateral load. Finite element modelling was conducted to consider the effects of the following variables on the horizontal stress redistribution: the ratio of the equivalent width of the extracted area to the overburden depth, the ratio of the original horizontal to vertical in situ stress components, and anisotropy in the rock mass behaviour. The key findings of this research are that the maximum horizontal stress induced as a consequence of extracting multiple supercritical longwall panels will be within approximately 10% of the original in situ horizontal stress for the case of isotropic rock strata. The magnitude of this horizontal stress may be larger in a stiff stratum if the overall sequence of strata consists predominantly of softer rocks. Anisotropy in the strata underlying the extracted longwall panels also causes an increase in the maximum horizontal stress induced into the immediate floor of the first extracted seam, and an increase in the rate of dissipation of horizontal stress change with depth. These findings indicate that a significant increase in horizontal stress relative to the original in situ horizontal stress should not be expected in multi-seam mining situations. The results from this study need to be considered in conjunction with predicted vertical stress distributions in order to accurately predict the overall stress environment likely to be encountered when conducting multi-seam mining. © 2014 Elsevier Ltd.
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Nova |
2014 |
Li AJ, Merifield RS, Lin HD, Lyamin AV, 'Trench stability under bentonite pressure in purely cohesive clay', International Journal of Geomechanics, 14 151-157 (2014) [C1]
Trench stability is a conventional geotechnical problem; however, current evaluations are often based entirely on empiricism. This paper uses numerical finite-element upper and lo... [more]
Trench stability is a conventional geotechnical problem; however, current evaluations are often based entirely on empiricism. This paper uses numerical finite-element upper and lower bound limit analysis to produce stability charts for two-dimensional and three-dimensional homogeneous and inhomogeneous undrained diaphragm wall trenches. Using the limit theorems cannot only provide a simple and useful way of analyzing the stability of the trench, but also avoid the shortcomings and arbitrary assumptions underpinning the limit equilibrium method. By considering the effects from the bentonite slurry pressures, the collapse load in this study has been bracketed to within ±8.5 or better by the numerical upper and lower bound limit analyses. The chart solutions can be used to predict either the critical depth or the safety factor of the trench and provide a convenient tool for preliminary designs by practicing engineers. © 2014 American Society of Civil Engineers.
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Nova |
2014 |
Ansari Y, Merifield R, Sheng D, 'A piezocone dissipation test interpretation method for hydraulic conductivity of soft clays', SOILS AND FOUNDATIONS, 54 1104-1116 (2014)
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2014 |
Ansari Y, Merifield R, Sheng D, 'A piezocone dissipation test interpretation method for hydraulic conductivity of soft clays', Soils and Foundations, 54 1104-1116 (2014) [C1]
An alternative approach is developed in order to estimate the hydraulic conductivity of soft fine grained soils, based on numerical simulation of the full penetration and dissipat... [more]
An alternative approach is developed in order to estimate the hydraulic conductivity of soft fine grained soils, based on numerical simulation of the full penetration and dissipation process for piezocones. Unlike previous methods of analysis, the process of penetration and dissipation has been explicitly simulated, thus eliminating several of the simplifications inherent in existing interpretation methods such as geometric approximations, predefined stress fields or neglecting material compressibility. The presented method is not established upon a particular set of data leading to limited applicability, but is rather developed using a more general approach and can be extended to other datasets if intended. Given the time to 50% consolidation and a number of influencing soil parameters, a single estimate of the soil horizontal permeability can be obtained via a single-run piezocone sounding using pore pressure measurements taken at the shoulder filter element (u2) located immediately behind the cone. The proposed interpretation method embodies many of the key parameters (namely the soil shear strength, soil rigidity, and soil confining stresses) likely to influence the soil behaviour and thus the parameter to be interpreted. Numerical analyses demonstrated that the rate of dissipation increases as the soil rigidity or the soil confining pressure increases, which is a consequence of higher excess pore pressure gradient at higher depths or at larger rigidities. The method, which involves a new excess pore pressure normalisation technique, is applicable to both monotonic and dilative dissipation data. The proposed interpretation method is compared to a series of experimental data including two recent field tests. Although the method was calibrated against only a select few cases, its applicability to a wide range of clayey soils was verified.
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Nova |
2013 |
Wang D, Merifield RS, Gaudin C, 'Uplift behaviour of helical anchors in clay', CANADIAN GEOTECHNICAL JOURNAL, 50 575-584 (2013) [C1]
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Nova |
2013 |
Suchowerska AM, Merifield RS, Carter JP, 'Vertical stress changes in multi-seam mining under supercritical longwall panels', INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, 61 306-320 (2013) [C1]
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Nova |
2012 |
Merifield R, 'Closure to "Ultimate Uplift Capacity of Multiplate Helical Type Anchors in Clay" by R. S. Merifield', JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING, 138 1428-1428 (2012)
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2012 |
Li AJ, Cassidy MJ, Wang Y, Merifield RS, Lyamin AV, 'Parametric Monte Carlo studies of rock slopes based on the Hoek-Brown failure criterion', Computers and Geotechnics, 45 11-18 (2012) [C1]
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Nova |
2012 |
Suchowerska A, Merifield RS, Carter JP, Clausen J, 'Prediction of underground cavity roof collapse using the Hoek-Brown failure criterion', Computers and Geotechnics, 44 93-103 (2012) [C1]
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Nova |
2012 |
Nguyen VQ, Merifield RS, 'Two- and three-dimensional undrained bearing capacity of embedded footings', Australian Geomechanics Journal, 47 25-40 (2012) [C1]
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Nova |
2011 |
Shiau JS, Merifield RS, Lyamin AV, Sloan SW, 'Undrained Stability of Footings on Slopes', International Journal of Geomechanics, 11 381-390 (2011) [C1]
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Nova |
2011 |
Li AJ, Merifield RS, Lyamin AV, 'Effect of rock mass disturbance on the stability of rock slopes using the Hoek-Brown failure criterion', Computers and Geotechnics, 38 546-558 (2011) [C1]
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Nova |
2011 |
Ansari Y, Merifield RS, Yamamoto H, Sheng D, 'Numerical analysis of soilbags under compression and cyclic shear', Computers and Geotechnics, 38 659-668 (2011) [C1]
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2011 |
Merifield RS, 'Ultimate Uplift Capacity of Multiplate Helical Type Anchors in Clay', Journal of Geotechnical and Geoenvironmental Engineering, 137 704-716 (2011) [C1]
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2011 |
Nguyen QV, Merifield RS, 'Undrained bearing capacity of surface footings near slopes', Australian Geomechanics Journal, 46 77-94 (2011) [C1]
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Nova |
2010 |
Merifield RS, Smith CC, 'The ultimate uplift capacity of multi-plate strip anchors in undrained clay', Computers and Geotechnics, 37 504-514 (2010) [C1]
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Nova |
2010 |
Li AJ, Merifield RS, Lyamin AV, 'Three-dimensional stability charts for slopes based on limit analysis methods', Canadian Geotechnical Journal, 47 1316-1334 (2010) [C1]
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Nova |
2009 |
Li AJ, Lyamin AV, Merifield RS, 'Seismic rock slope stability charts based on limit analysis methods', Computers and Geotechnics, 36 135-148 (2009) [C1]
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Nova |
2009 |
Li AJ, Merifield RS, Lyamin AV, 'Limit analysis solutions for three dimensional undrained slopes', Computers and Geotechnics, 36 1330-1351 (2009) [C1]
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Nova |
2009 |
Merifield RS, White DJ, Randolph MF, 'Effect of surface heave on response of partially embedded pipelines on clay', Journal of Geotechnical and Geoenvironmental Engineering, 135 819-829 (2009) [C1]
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Nova |
2008 |
Li AJ, Merifield RS, Lyamin AV, 'Stability charts for rock slopes based on the Hoek-Brown failure criterion', International Journal of Rock Mechanics and Mining Sciences, 45 689-700 (2008) [C1]
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Nova |
2008 |
Merifield RS, White DJ, Randolph MF, 'The ultimate undrained resistance of partially embedded pipelines', Geotechnique, 58 461-470 (2008) [C1]
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Nova |
2006 |
Merifield RS, Lyamin AV, Sloan SW, 'Limit analysis solutions for the bearing capacity of rock masses using the generalised Hoek-Brown criterion', International Journal of Rock Mechanics and Mining Sciences, 43 920-937 (2006) [C1]
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2006 |
Merifield RS, Nguyen VQ, 'Two- and three-dimensional bearing-capacity solutions for footings on two-layered clays', Geomechanics and Geoengineering, 1 151-162 (2006) [C1]
In this paper, finite element analysis is used to predict the undrained bearing capacity of strip, square and circular footings resting on layered clays. The soil profile consists... [more]
In this paper, finite element analysis is used to predict the undrained bearing capacity of strip, square and circular footings resting on layered clays. The soil profile consists of two clay layers with different thicknesses and properties. The results are compared with previous solutions for strip footings on layered clays. The bearing-capacity behaviour is discussed and the bearing-capacity factors are given for various cases involving a range of layer thicknesses and properties of the two clay soil layers. © 2006 Taylor & Francis Group, LLC.
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2006 |
Merifield RS, Sloan SW, 'The ultimate pullout capacity of anchors in frictional soils', Canadian Geotechnical Journal, 43 852-868 (2006) [C1]
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2006 |
Merifield RS, Lyamin AV, Sloan SW, 'Three-dimensional lower-bound solutions for the stability of plate anchors in sand', Geotechnique, 56 123-132 (2006) [C1]
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2005 |
Merifield RS, Lyamin AV, Sloan SW, 'Stability of inclined strip anchors in purely cohesive soil', Journal of Geotechnical and Geoenvironmental Engineering, 131 792-799 (2005) [C1]
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2003 |
Merifield RS, Lyamin AV, Sloan SW, Yu H-S, 'Three-Dimensional Lower Bound Solutions For Stability Of Plate Anchors In Clay', Journal Of Geotechnical And Geoenvironmental Engineering, 129 243-253 (2003) [C1]
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2001 |
Merifield RS, Sloan SW, Yu H-S, 'Stability of plate anchors in undrained clay', Geotechnique, 51 141-153 (2001) [C1]
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1999 |
Merifield RS, Sloan SW, Yu H-S, 'Rigorous plasticity solutions for the bearing capacity of two-layered clays', Geotechnique, Vol. 49 471-490 (1999) [C1]
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