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Laboratory investigation on the single particle crushing strength of carbonate gravel incorporating size and shape effects Géotechnique (IF 5.8) Pub Date : 2023-12-20 Xin Liu, Sa Li, Ting Yao
Particle strength is one of the critical factors that causes the degradation of the mechanical behaviour of crushable soil. Because of the complexity of particle shape, its effect on particle strength has not been completely understood. In this study, single particle crushing tests were performed on carbonate gravel particles with three size fractions (i.e. 5–10 mm, 10–15 mm and 15–20 mm) and three
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Liquefaction susceptibility of clayey sands under saturated and partially saturated conditions Géotechnique (IF 5.8) Pub Date : 2023-12-20 Pedram Fardad Amini, Jun Yang
Experiences from previous earthquake events have indicated that sands containing non-plastic (silt) or plastic (clay) fines are susceptible to liquefaction. These experiences underline the need for improving the fundamental understanding of the seismic behaviour of silty and clayey sands and for developing appropriate methods to evaluate their liquefaction potential. This paper presents an attempt
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Water infiltration in drained circular tunnels: an analytical solution and its simplification Géotechnique (IF 5.8) Pub Date : 2023-12-19 Jinfeng Bi, Hong Jiang
Underwater tunnels are often subject to groundwater infiltration, which can pose risks both to the tunnel's safety and the groundwater environment. Analytical solutions are commonly used to estimate the rate of water infiltration in tunnels. However, there is a lack of research on the analytical solution of tunnels with drainage systems. The aim of this study was to investigate groundwater seepage
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Effect of strain-softening and strength anisotropy on the undrained bearing capacity of non-associated clay Géotechnique (IF 5.8) Pub Date : 2023-12-14 Yuepeng Dong
The bearing capacity of soils is critical in the design and analysis of foundations. The classical solutions derived from methods of characteristics and bound theories are based on the rigid plasticity and associated flow rule, which may not be realistic for natural soils. The undrained shear strength of soft clays exhibits strain-softening and anisotropic behaviour in laboratory tests, which creates
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Effect of salinity on the effective stress of compacted bentonites Géotechnique (IF 5.8) Pub Date : 2023-12-12 Vicente Navarro, Laura Asensio
Adopting a double-porosity macroscopic modelling framework, a general formulation of the effective stress in compacted bentonites is derived from basic thermodynamic principles. The formulation indicates that, when there is equilibrium between macrostructural and microstructural water, the effect of salinity is affected by a factor that is equal to the ratio of the overall bulk modulus of the soil
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Small-strain shear modulus of silty sands: the role of sample preparation method Géotechnique (IF 5.8) Pub Date : 2023-12-06 Yutang Chen, Jun Yang
Establishing the influence of sample preparation method on shear wave velocity or associated small-strain shear modulus (G0) of silty sands is a subject of considerable interest. This paper presents an attempt to address this topic through a comprehensive experimental programme covering four sample preparation methods. The experiments were conducted on clean Toyoura sand and its mixtures with two types
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On drilling speed of London Clay from MWD data with time-series algorithm for ground characterisation Géotechnique (IF 5.8) Pub Date : 2023-12-05 Si Yuan Wu, Wendal Victor Yue, Zhongqi Quentin Yue
The ground conditions around an old tunnel in London Clay strata were extensively studied. The correlation between ‘measurement while drilling’ (MWD) drilling parameters and drillhole investigation results, however, was not satisfactory due to the significant noise in the drilling speed. In this paper the original MWD data published in the literature are re-examined and the associated noise issue is
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Shear behaviour of sand–rubber mixtures: interpretation from energy transformation and force chain evolution Géotechnique (IF 5.8) Pub Date : 2023-12-05 Ning Guo, Yihao Shi, Zheng Hu, Zhongxuan Yang
This study investigates the effect of rubber particles on biaxial shear responses of sand–rubber mixtures (SRMs) using a multibody mesh-free method, which enables the flexible and robust modelling of visco-elastic deformation of rubber particles. From the energy evolutions in SRMs with different rubber contents (RCs), including the incremental elastic strain energy, friction slipping dissipation and
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Dry granular flow in a vane shear cell: flow characteristics and rheological laws Géotechnique (IF 5.8) Pub Date : 2023-12-05 Mohsen Kamali Zarch, Limin Zhang, S. Mohsen Haeri, Zhengdan Xu
The flow dynamics of dry granular flows is significantly affected by a prominent feature of a granular mass known as dilatancy. Although their rheological behaviour has been characterised by way of friction and dynamic dilatancy laws, the role of dilatancy in a granular flow has not been much appreciated. In this study, using a vane rheometer, an experimental investigation was conducted on uniform
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Sample size effects on the critical state shear strength of granular materials with varied gradation and the role of column-like local structures Géotechnique (IF 5.8) Pub Date : 2023-12-04 David Cantor, Carlos Ovalle
Assessing the shear strength of coarse granular soils is challenging because testing devices in the laboratory often limit the maximum particle size (dmax). Although engineering standards define representative elementary volumes (REVs) using the aspect ratio α = X/dmax, where X is the characteristic sample size, they often disagree on the minimum α, as the effects of sample scale on shear strength
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Cyclic liquefaction of granular materials with varied forms under multidirectional loads Géotechnique (IF 5.8) Pub Date : 2023-11-30 Shao-Heng He, Zhen-Yu Yin, Zhi Ding
Both liquefaction resistance of granular materials under complex multidirectional cyclic loadings and influence of particle form or morphology on it are poorly understood. This paper presents an experimental investigation on this topic. Round, frosted, concave, and convex glass beads as well as Hong Kong CDG sand were used to prepare samples with varying particle morphologies (i.e., roughness, sphericity
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A microscopic interpretation of hysteresis in the water retention curve of sand Géotechnique (IF 5.8) Pub Date : 2023-11-30 Yosuke Higo, Ryunosuke Kido
The hysteresis observed in the water retention curve was experimentally studied through the use of X-ray micro-computed tomography. The CT images were acquired during the main drying and wetting processes of a water retention test for uniform sand. The porosity and degree of saturation (Sr) of pore-scale local subsets were calculated using images segmented into soil, water, and air phases. The simultaneous
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Thermo-mechanical behaviour of a kaolin-based clay soil Géotechnique (IF 5.8) Pub Date : 2023-11-29 Andrew Kirkham, Aikaterini Tsiampousi, David M. Potts
The thermal behaviour of KSS, a low-plasticity artificial clay made with kaolin clay, silt and sand, was investigated in a series of temperature-controlled oedometer tests, at temperatures between 5°C and 70°C, and at vertical pressures up to 2·4 MPa. The experiments investigated the effect of overconsolidation ratio (OCR), pressure level and repeated thermal cycling on thermally induced volume change
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Limit-state solutions for the active earth pressure behind walls rotating about the base Géotechnique (IF 5.8) Pub Date : 2023-11-29 David Perozzi, Alexander M. Puzrin
Determining earth pressure-induced moments in the active limit state is critical for the safety assessment of retaining structures. While traditional design methods assume a Coulomb's resultant force acting at one-third of the wall height, the literature suggests that the earth pressure distribution depends on the failure mode. This paper presents a rigorous kinematic solution for the ultimate moment
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Influence of injection methods on bio-mediated precipitation of carbonates in fracture-mimicking microfluidic chip Géotechnique (IF 5.8) Pub Date : 2023-11-29 Chang Zhao, Yang Xiao, Xiang He, Hanlong Liu, Yi Liu, Jian Chu
Enzymatically induced carbonate precipitation (EICP) is a potential method to alter the hydraulic properties of fractured rocks. The pore-scale in situ formation of bio-mediated precipitated carbonates in fracture-mimicking channels was investigated experimentally through a visualisation platform and microfluidic technology. Image processing was employed to analyse the precipitation behaviour. Three
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Influence of recycled rubber mat on the behaviour of ballast under impact loading: experimental and numerical modelling Géotechnique (IF 5.8) Pub Date : 2023-11-24 Trung Ngo, Buddhima Indraratna, Matthew Coop, Yujie Qi
During the passage of trains, dynamic impact loads caused by wheel imperfections or rail abnormalities cause significant ballast degradation. In this study, the use of rubber mats manufactured from recycled tyres placed underneath a ballast layer is investigated to mitigate the adverse effects of impact loads. Based on a series of tests conducted using a high-capacity drop-weight facility to evaluate
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Non-coaxiality behaviours and unified flow rule of soil–structure interfaces Géotechnique (IF 5.8) Pub Date : 2023-11-22 Dakuo Feng, Jianmin Zhang
Non-coaxiality is one of the key characteristics of soil–structure interfaces that broadly occur in geotechnical engineering. A series of interface tests between gravel and a structure was performed to address and model the non-coaxiality behaviours of interfaces subjected to various three-dimensional (3D) loadings. Non-coaxiality of the interface was identified during the yielding phase when subjected
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Time-dependent processes influencing offshore foundations in clay: an experimental study on plate anchors Géotechnique (IF 5.8) Pub Date : 2023-11-21 Ci Wang, Conleth D. O'Loughlin, Fraser Bransby, Phil Watson, Zefeng Zhou
Motivation for this paper stems from experimental investigations that consider how the vertical capacity of a horizontal circular plate anchor in clay changes due to consolidation. These experiments produced interesting time-dependent measurements that prompted a follow-on study, designed to explore the underlying mechanisms. The new experimental data indicate that changes in anchor load during consolidation
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Engineered bioclogging in sands: comparison of microbially induced and enzyme-induced biopolymer formation Géotechnique (IF 5.8) Pub Date : 2023-11-21 Yong-Min Kim, Tae-Hyuk Kwon
This study presents two methods of producing an insoluble biopolymer, the microbially induced biopolymer formation (MIBF) and enzyme-induced biopolymer formation (EIBF) and explores their ability to reduce hydraulic conductivity and cause bioclogging in soil from pore to column scales. The batch experiments confirm that insoluble polysaccharidic biopolymers, dextran, are successfully produced either
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A nonlinear static analysis for the seismic design of single-span integral abutment bridges Géotechnique (IF 5.8) Pub Date : 2023-11-20 Domenico Gallese, Davide Noè Gorini, Luigi Callisto
Integral abutment bridges are characterised by a monolithic connection between the deck and the abutments. Because of this connection, the seismic behaviour of the entire structure tends to be controlled by its interaction with the surrounding soil, and especially with the approach embankments. To date, methods for the seismic design of this type of bridges are still characterised by substantial uncertainties
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A thermomechanical model for argillaceous hard soils–weak rocks: application to THM simulation of deep excavations in claystone Géotechnique (IF 5.8) Pub Date : 2023-11-15 Saeed Tourchi, Miguel A. Mánica, Antonio Gens, Jean Vaunat, Minh-Ngoc Vu, Gilles Armand
The paper presents the enhancement of an existing constitutive model for argillaceous hard soils–weak rocks to incorporate non-isothermal conditions, to be used in coupled thermo-hydro-mechanical (THM) simulations of underground excavations subjected to temperature variations within the context of deep geological nuclear waste disposal. The proposed thermo-elastoplastic extension accounts for the effect
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Influence of the head fixity adjustment of existing piles on the lateral load response of new piles Géotechnique (IF 5.8) Pub Date : 2023-11-09 Hongjiang Li, Songyu Liu, Liyuan Tong, Dingwen Zhang
The reuse of existing piles is a significant path to achieving low-carbon-dioxide, resilient and sustainable urban construction. However, some key issues in this area remain unresolved, especially with regard to the lateral interaction of new and existing piles. In this study, centrifuge tests and numerical simulations were used to investigate the influence of the head fixity adjustment of existing
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Matching of crushed highly decomposed granite particles using 3D SHOT descriptors Géotechnique (IF 5.8) Pub Date : 2023-11-09 Zhiren Zhu, Jianfeng Wang
Owing to the complex morphology and the fragility of highly decomposed granite (HDG), it is still a challenge to track the breakage process of HDG particles within a deformed sample in geomechanics research. An HDG particle matching method is proposed in this paper for the first time to track and match HDG fragments with their mother particles from which they break off. First, the X-ray micro-computed
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Updating model parameters and predictions in SEM tunnelling using a surrogate-based Bayesian approach Géotechnique (IF 5.8) Pub Date : 2023-11-02 Haotian Zheng, Michael Mooney, Marte Gutierrez
This paper presents a surrogate-based Bayesian approach for updating the ground parameters within an application of the observational method in sequential excavation method (SEM) construction. A three-dimensional (3D) finite-difference model is used in the forward analysis to simulate SEM construction explicitly considering 3D multi-face excavation effects and ground–structure interaction. The polynomial-chaos
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Non-stationary anisotropy-dependent critical state for clays Géotechnique (IF 5.8) Pub Date : 2023-10-27 Hesam Dejaloud, Mohammad Rezania, Nasser Khalili
In this paper, the effect of fabric anisotropy on the critical state behaviour of clays is investigated. An original concept of moving critical state is elaborated by a novel state parameter-based rotational hardening rule that is subsequently used to formulate a complete anisotropic elastoplastic constitutive model for clays. It is shown that some of the distinctive pre-failure and critical state
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Numerical modelling of inflatable steel-tube rock bolt considering non-linear contact behaviour Géotechnique (IF 5.8) Pub Date : 2023-10-25 Kyeong-Cheol Kim, Ho-Jong Kim, Kang-Hyun Kim, Jong-Ho Shin
Inflatable steel-tube rock bolts are useful as they can introduce a pull-out resistance immediately after installation and do not cause a loss of frictional force under the existing groundwater environment. The anchoring mechanism and pull-out resistance of the inflatable steel tube has been basically explained through theoretical studies. The contact behaviour between the tube and borehole rock is
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Anisotropic small-strain stiffness of lightly biocemented sand considering grain morphology Géotechnique (IF 5.8) Pub Date : 2023-10-12 Jinquan Shi, Yang Xiao, J. Antonio H. Carraro, Haoyu Li, Hanlong Liu, Jian Chu
Small-strain stiffness and stiffness anisotropy of a sand are sensitive to the sand fabric, which can be significantly affected by particle shape and cementation. In this study, multidirectional bender element and isotropic compression tests were performed on glass sands with different particle shapes and biocementation levels. The small-strain stiffness and stiffness anisotropy of the untreated and
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Frequency dependence of acoustic emission with particle interaction and failure process in dry sands during triaxial compression Géotechnique (IF 5.8) Pub Date : 2023-10-12 Wenli Lin, Ang Liu, Wuwei Mao, Junichi Koseki
To investigate the behaviour of sands at the particle-scale during shear failure, a series of triaxial compression tests was conducted on dry sands with varying confining stresses and relative densities. These tests were complemented by acoustic emission (AE) monitoring to analyse the frequency-dependent AE signals and characterise particle interactions in terms of crushing (>100 kHz) and rearrangement
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Coupled peridynamics modelling of liquefaction-induced shear strain localisation and delayed failure Géotechnique (IF 5.8) Pub Date : 2023-10-09 Wei Sun, Rui Wang, Jian-Min Zhang
Liquefaction-induced shear strain localisation and delayed failure occur when a low-permeability overlying soil layer impedes the dissipation of excess pore water pressure generated by the underlying sand. When this phenomenon is simulated by the classical finite-element method (FEM), the predicted strain localisation and lateral deformation are mesh-size dependent. In this study, the non-local peridynamics
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Influence of the head fixity adjustment of existing piles on the lateral load response of new piles Géotechnique (IF 5.8) Pub Date : 2023-10-06 Hongjiang Li, Songyu Liu, Liyuan Tong, Dingwen Zhang
The reuse of existing piles is a significant path to achieving low-carbon, resilient, and sustainable urban construction. However, some key issues in this area remain unresolved, especially with regard to the lateral interaction of new and existing piles. This study used centrifuge tests and numerical simulations to investigate the influence of the head fixity adjustment of existing piles on the lateral
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Matching of crushed highly decomposed granite particles using 3D SHOT descriptors Géotechnique (IF 5.8) Pub Date : 2023-10-06 Zhiren Zhu, Jianfeng Wang
Due to the complex morphology and the fragility of highly decomposed granite (HDG), it is still a challenge to track the breakage process of the HDG particles within a deformed sample in geomechanics research. A HDG particle matching method is proposed in this paper for the first time to track and match HDG fragments with their mother particles from which they break off. Firstly, the X-ray micro-computed
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Shear resistance relaxation of granular materials under vibration and restricted deforming conditions Géotechnique (IF 5.8) Pub Date : 2023-09-28 Tao Xie, Peijun Guo, Dieter Stolle
The phenomenon of vibration-induced shear resistance relaxation (ViSRR) refers to the loss of shear resistance in granular materials subjected to vibration, without an observable increase of excess pore pressure, under restricted deforming conditions. Essentially, ViSRR occurs when the total deformation of granular materials is unable to keep up with the plastic deformation induced by the vibration
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Representation of three-dimensional unsaturated flow in heterogeneous soil through tractable Gaussian random fields Géotechnique (IF 5.8) Pub Date : 2023-09-25 Evan John Ricketts, Peter John Cleall, Anthony Jefferson, Pierre Kerfriden, Paul Lyons
The representation of the spatial variability of soil properties is required to model non-uniform hydrological flow processes such as fingering and preferential moisture migration, which are prominent in both unsaturated and hydrophobic soils. This paper presents a new method for simulating three-dimensional hydrological flow processes in soil masses in which random fields of soil properties are conveniently
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In vitro screening of crude urease extract from native Australian plants and weeds for bio-cementation of sands Géotechnique (IF 5.8) Pub Date : 2023-09-25 Md Mizanur Rahman, Isaac Ahenkorah, Md Rajibul Karim, Simon Beecham
Urease enzymes from plants are directly utilised in enzyme-induced calcite precipitation (EICP) to catalyse calcium carbonate (CaCO3) precipitation between soil particles to improve their strength and stiffness. EICP does not require microbial culture and may be applicable for finer soils with their smaller size. However, most studies on EICP utilise purified urease enzymes, which are often rare, expensive
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DEM modelling of root circumnutation-inspired penetration in shallow granular materials Géotechnique (IF 5.8) Pub Date : 2023-09-21 Yuyan Chen, Alejandro Martinez
Plant root growth is often accompanied by circumnutative motion consisting of downward helical movement of the root tip. Previous studies indicate that circumnutations allow roots to avoid obstacles that would impede root growth, while other studies show that circumnutations can reduce the penetration resistance mobilised during root growth. Discrete-element modelling (DEM) simulations were performed
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Characteristics of MICP- and EICP-treated sands in simple shear conditions: a benchmarking with the critical state of untreated sand Géotechnique (IF 5.8) Pub Date : 2023-09-21 Isaac Ahenkorah, Md Mizanur Rahman, Md Rajibul Karim, Simon Beecham
Microbial- or enzyme-induced calcium carbonate (CaCO3) precipitation (MICP and EICP) are relatively new ground improvement techniques. In this study, the mechanical behaviour of biotreated (MICP/EICP) and untreated sands was investigated in light of the critical state soil mechanics framework using a series of direct simple shear (DSS) tests. A wide range of calcium carbonate content (CC), initial
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Monitoring the construction of a deep energy-from-waste bunker in soft clay and peat Géotechnique (IF 5.8) Pub Date : 2023-09-08 Peter J. Hensman, Zhandos Y. Orazalin, Brian B. Sheil
This paper describes the monitoring of the construction of a deep underground waste storage bunker for the PROTOS energy-from-waste facility in Chester, UK. A key element of the construction process was a 12 m deep excavation in soft clays and peats which was supported by a complex ‘combi-wall’ cofferdam comprising alternate tube and sheet piles, a reinforced concrete (RC) capping beam and two levels
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The contact mechanics of a UK railway ballast Géotechnique (IF 5.8) Pub Date : 2023-08-24 Cacin P. Y. Wong, Matthew R. Coop
A newly developed apparatus was used to investigate the contact mechanics between particles of a common UK railway ballast. The data were then compared with the models currently and commonly used in geotechnical discrete-element method (DEM) analyses, but the discrepancy between the predictions and measurements is large even at small loads. The first contact behaviour was much softer than the Hertz–Mindlin
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A hydrodynamic model for chemo-mechanics of poroelastic materials Géotechnique (IF 5.8) Pub Date : 2023-08-23 Yanni Chen, François Guillard, Itai Einav
Chemical dissolution along interfaces between solid skeleton and pore fluids tends to alter geomaterials and may cause catastrophic failures. Following the hydrodynamic procedure, this work develops a mathematically rigorous and thermodynamically consistent modelling framework to investigate the impact of chemo-mechanical coupling on the constitutive properties of poroelastic geomaterials. The formulation
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A novel bio-carbonation method of reactive magnesia with urea pre-hydrolysis for geomaterial stabilisation Géotechnique (IF 5.8) Pub Date : 2023-08-16 Dian-Long Wang, Chao-Sheng Tang, Xiao-Hua Pan, Rui Wang, Min Shi, Zhi-Hao Dong, Yi-Cheng Zhang, Bin Shi
This study proposes a novel bio-carbonation method of reactive magnesia cement (RMC) with urea pre-hydrolysis for geomaterial stabilisation. Urea pre-hydrolysis in the bacterial solution before mixing with RMC produces more carbonate and ammonia, facilitating the RMC bio-carbonation to form more hydrated magnesia carbonates (HMCs), the dominant product that contributes to strength gain. The effect
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Optimal adaptive decision rules in geotechnical construction considering uncertainty Géotechnique (IF 5.8) Pub Date : 2023-08-16 Elizabeth Bismut, Dafydd Cotoarbă, Johan Spross, Daniel Straub
To design a geotechnical engineering structure optimally, an iterative decision-making process is required due to the prevailing uncertainty of the ground conditions. At present, these decisions are taken based on simple deterministic rules and models. This paper proposes a risk-based decision-theoretic framework to the optimal planning for geotechnical construction. This framework combines geotechnical
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Drained instability of coarse oil sand tailings Géotechnique (IF 5.8) Pub Date : 2023-08-02 Abouzar Sadrekarimi, Grytan Sarkar
Lateral stress relief and effective stress reduction have been recognised as the culprits in flow failures of several mine tailings dams. This research examines the instability of coarse oil sand tailings (CSTs) subjected to such a stress path through a series of monotonic direct simple shear tests. To investigate the impact of tailings fabric, laboratory specimens were reconstituted by moist-tamping
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Particle-scale simulations of the compression and shearing of kaolin clay Géotechnique (IF 5.8) Pub Date : 2023-08-02 John P. de Bono, Glenn R. McDowell
This paper presents a new model for particle-scale simulations of clay. Using the discrete-element method, featuring realistically shaped platelets with separate interactions between the various platelet surfaces, simulations of isotropic normal compression and triaxial shearing are performed. A normal compression line is established, and for the first time so is a critical state line, which is parallel
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The role of abrasion in cyclically sheared soil–structure interfaces Géotechnique (IF 5.8) Pub Date : 2023-07-17 Angus Pettey, Charles M. Heron
A limiting factor in the drive to deliver performance-based design is the lack of knowledge regarding the constitutive behaviour of soil–structure interfaces, particularly in the case of cyclic loading. A series of experiments was undertaken using both a traditional interface shear apparatus (shearing a large body of soil grains over a structural interface) and a novel single-particle interface shear
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Exploring particle breakage in sand under triaxial shearing using combined X-ray tomography and particle tracking method Géotechnique (IF 5.8) Pub Date : 2023-07-17 Mengmeng Wu, Jianfeng Wang
In this paper, a novel investigation of the particle breakage behaviour of sands is made using combined techniques of X-ray micro-computed tomography (μCT) and sand particle tracking. First, an in situ μCT triaxial test on a miniature sand specimen is conducted to allow the visualisation of particle-scale morphology and movement. Then a two-step particle tracking method is developed and applied to
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Numerical modelling of a tunnel adjacent to a surface structure in liquefiable ground Géotechnique (IF 5.8) Pub Date : 2023-07-12 Jinghua Zhang, Emilio Bilotta, Gopal S. P. Madabhushi, Yong Yuan
Earthquake-induced liquefaction is likely to cause uplift displacements of underground structures and excessive settlements of surface structures. While these two phenomena have been investigated separately in the literature, the case of a shallow tunnel buried adjacent to a surface structure in liquefiable ground has not yet been thoroughly studied. In this paper, the OpenSees platform is employed
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Experimental micro–macromechanics: particle shape effect on the biaxial shear response of particulate systems Géotechnique (IF 5.8) Pub Date : 2023-07-03 Usman Ali, Mamoru Kikumoto, Matteo Ciantia, Marco Previtali, Ying Cui
The effect of particle shape on micro and macroscopic behaviour is investigated experimentally through a series of biaxial compression tests on round and angular rods. Dual-size assemblies of thousands of circular (round) or hexagonal (angular) particles were sheared under three confining pressures. The displacement, rotation and evolution of coordination number of all the particles during the shearing
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A novel T-bar test method ensuring full-flow mechanism in stiffer clay Géotechnique (IF 5.8) Pub Date : 2023-06-28 Yunrui Han, Long Yu, Zhongtao Wang, Qing Yang, Yuxia Hu
The T-bar penetrometer is currently used to characterise seabed sediments, mostly based on the full-flow mechanism around the probe in soft clays. However, open and trapped cavities may form above the T-bar during its penetration in stiffer clays, which can make the traditional interpretation method inaccurate and requires complex corrections. This paper proposes a novel T-bar test method by adding
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Particle-scale simulations of the compression and shearing of kaolin clay Géotechnique (IF 5.8) Pub Date : 2023-06-22 John de Bono, Glenn McDowell
This paper presents a new model for particle-scale simulations of clay. Using the discrete element method (DEM), featuring realistically-shaped platelets with separate interactions between the various platelet surfaces, simulations of isotropic normal compression and triaxial shearing are performed. A normal compression line is established, and for the first time so is a critical state line, which
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Torsional installation and vertical tensile capacity of helical piles in clay Géotechnique (IF 5.8) Pub Date : 2023-06-20 Shah Neyamat Ullah, Conleth O'Loughlin, Yuxia Hu, Lee Fook Hou
Helical piles are being increasingly considered for offshore applications as they avoid the acoustic emissions associated with pile driving, and they provide additional capacity relative to a driven pile. In this paper, the installation and tensile capacity of helical piles is considered through a combination of centrifuge experiments and large-deformation finite-element analyses within a coupled Eulerian–Lagrangian
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Exploring particle breakage in sand under triaxial shearing using combined X-ray tomography and particle tracking method Géotechnique (IF 5.8) Pub Date : 2023-06-19 Mengmeng Wu, Jianfeng Wang
In this paper, a novel investigation of the particle breakage behavior of sands is made using combined techniques of X-ray micro-computed tomography (μCT) and sand particle tracking. Firstly, an in-situ μCT triaxial test on a miniature sand specimen was conducted to allow the visualization of particle-scale morphology and movement. Then a two-step particle tracking method is developed and applied to
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Centrifuge and theoretical study of the seismic response of anchored steel sheet pile walls in dry sand Géotechnique (IF 5.8) Pub Date : 2023-06-05 Alessando Fusco, Riccardo Conti, Giulia M. B. Viggiani, Gopal S. P. Madabhushi, Cécile Prüm
Displacement-based approaches have been proven to be effective for the seismic design of gravity retaining structures. However, application of these methods to embedded flexible walls, such as anchored steel sheet pile (ASSP) walls, is still an open issue, as the factors affecting the accumulation of permanent displacements of these systems are not fully understood. This paper presents the results
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Full-scale model tests on ballasted tracks with/without geogrid stabilisation under high-speed train loads Géotechnique (IF 5.8) Pub Date : 2023-06-02 Zheng Luo, Chuang Zhao, Wenqing Cai, Qiusheng Gu, Weian Lin, Xuecheng Bian, Yunmin Chen
High-speed trains running on ballasted tracks intensify the vibration of ballast layers to a greater extent than conventional passenger trains, with detrimental effects to train operations. The stabilisation effect of the geogrid in real railways under high-speed train moving loads remains unclear. Herein, full-scale model tests on a ballasted trackbed with and without geogrid were conducted, and a
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A novel T-bar test method ensuring full-flow mechanism in stiffer clay Géotechnique (IF 5.8) Pub Date : 2023-06-01 Yunrui Han, Long Yu, Zhongtao Wang, Qing Yang, Yuxia Hu
T-bar penetrometer is currently used to characterize seabed sediments mostly based on the full-flow mechanism around the probe in soft clays. However, open and trapped cavities may form above the T-bar during its penetration in stiffer clays, which can make the traditional interpretation method inaccurate and requires complex corrections. This paper proposes a novel T-bar test method by adding sufficient
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Reassessing variations in the small-strain stiffness of London Clay Géotechnique (IF 5.8) Pub Date : 2023-05-30 Truong Le, Jamie Standing, David Potts
High-quality rotary core samples of natural London Clay were taken during installation of subsurface instrumentation to monitor the ground response at Hyde Park, London, to the construction of Crossrail tunnels. An extensive programme of advanced triaxial tests was performed on specimens from London Clay divisions A3 to C. Detailed analysis of their response to undrained shearing in compression from
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Kinematic bending of piles in made ground Géotechnique (IF 5.8) Pub Date : 2023-05-30 Raffaele Di Laora
This work explores earthquake-induced kinematic bending in the so far unresolved case of a pile embedded in a two-layer soil with a thin surface layer. The problem is treated analytically by means of a generalised Winkler model, which in addition considers the effect of boundary conditions at the pile head over earlier contributions on the subject. Novel analytical closed-form expressions of the kinematic
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Integrated effects of inherent and induced anisotropy on reliquefaction resistance of Toyoura sand with different strain histories Géotechnique (IF 5.8) Pub Date : 2023-05-17 Pedram Fardad Amini, Gang Wang
Recent earthquakes in New Zealand and Japan showed that pre-shaking histories significantly affected the reliquefaction resistance of soils. In this study, a series of experimental tests was conducted to elucidate the coupled effects of inherent and induced anisotropy on reliquefaction resistance of Toyoura sand, which have not been studied before. Accordingly, loose and dense Toyoura sands were prepared
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Mind the gap – an experimental study on the need for grouting suction buckets in sand under vertical cyclic loading Géotechnique (IF 5.8) Pub Date : 2023-05-09 Francisco da Silva Pereira, Britta Bienen, Conleth D. O'Loughlin
Suction bucket jackets are increasingly being used to support bottom-fixed offshore wind turbines. It is generally assumed that contact between the underside of the bucket lid and the seabed is mandatory to safeguard against additional settlement. Lid contact is usually ensured by underwater grout injection, albeit this has a significant impact on the duration and costs of installation. Although grouting
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Estimating initiation conditions for extrusion buckling of driven open-ended piles Géotechnique (IF 5.8) Pub Date : 2023-05-02 Juliano A. Nietiedt, Mark F. Randolph, Christophe Gaudin, James P. Doherty
The potential for pile tip damage and extrusion buckling has become an increasing concern for the offshore wind industry following the trend toward the use of large-diameter thin-walled pile foundations, either as monopiles or as part of a jacket structure. Extrusion buckling may be triggered by an initial pile tip fabrication imperfection or pile damage during transport and handling. It may also be
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Undrained uplift resistance of under-reamed open caisson shafts Géotechnique (IF 5.8) Pub Date : 2023-04-24 Brian B. Sheil, Jack O. Templeman, Zhandos Orazalin, Bryn M. Phillips, Geyang Song
Deep, large-diameter caisson shafts are a popular means of constructing underground storage and attenuation tanks and pumping stations for the water and wastewater industry. One of the key design concerns for these structures is resistance to flotation during periods when the tanks are only partially filled or empty. In this paper, two-dimensional numerical analysis is used to explore the undrained