For highly-saturated soils, the effect of air bubbles on the consolidation of soil is mainly reflected by the compressibility of pore fluid. In this paper, the effect of compressible pore fluid and anisotropic permeability on the soil mechanism is investigated based on the Biot’s consolidation theory and analytical layer element method (ALEM). The response of pile in highly-saturated soils is further

Accurately predict the resistance of caisson penetrating in stratified soil deposits is an engineering challenge for application of such foundation system. This paper performs large deformation finite element analysis to investigate the penetration behavior of caisson foundations in non-uniform clay interbedded with a sand layer. The numerical model is validated by comparing with previously testing

The landslide-river interaction and the impulse waves involved in the landslide dam formation process may not be insignificant and have not been extensively investigated and simulated. This paper presents a numerical investigation on the formation process of landslide dams and resulting free surface flow dynamics in the impacted river via coupled discrete element method (DEM) and computational fluid

Porosity is an important variable in consolidation theory. However, porosity information is missing in Biot’s model when the solid constituent of the porous media is assumed to be compressible. This paper develops a macro–microscopic coupled consolidation model in order to track the evolution of the porosity for saturated porous media with compressible constituents. The proposed model exploits a u−εvsr−p

This study analyses the response of compacted bentonites upon hydration based on a coupled hydro-mechanical elasto-plastic framework. As an alternative to multi-porosity interpretation, the framework was selected based on the experimental evidence of adsorbed water behaviour in bentonites and the volumetric response at saturated states, apparently independent of its initial state. Based on these premises

A double-line metro tunnel was constructed beneath an existing high-speed railway bridge in a city of east China. To avoid the unexpected displacement of the bridge resulting from the shield tunneling, the displacement isolation piles were employed between the shield tunnels and the pile foundation of the bridge. An accompanied optimization design issue of the isolation piles is analyzed in this work

Numerical manifold method (NMM) based on finite covers provides a powerful tool for the analysis of engineering problems having complex discontinuities. However, the complicated geometric/topology operations and the block cutting procedure for generating physical covers seriously hinder the engineering practice of the NMM. In this work, local temporary pixels are constructed on the mathematical covers

This paper presents a novel unified model coupling soil volumetric hardening and water retention. The volumetric hardening law is formulated using the effective stress concept and can be applied to various soil types with unified formulations. This law also considers the influence of stress-induced anisotropy, and provides an enhanced prediction of soil response under elevated stress levels and loading–unloading

A reliability-based design (RBD) method for rigid pipes installed using induced trench with tire-derived aggregates (TDA) inclusion is introduced in this study. The design process is to find an optimal set of the TDA inclusion dimension (i.e., width B and thickness t) that satisfies the 0.01-inch crack serviceability limit state and ultimate failure limit state requirements of the pipe, and achieves

This paper presents a numerical study on passive earth pressure under undrained conditions. First, a simplified problem is investigated in order to evaluate the resulting earth pressure for a parallel movement of a rigid wall. It is shown that for undrained conditions the type of constitutive model employed has an influence on the limiting passive earth pressure. Comparison with limit analysis is provided

Pore-network models are useful for simulating physical processes in geological porous media. Here in this paper, the network theories are used to analyze X-ray computed tomography (CT) images of geological porous media. Results show the traditional mathematical degree which represents the coordination number of pore networks is insufficient to describe the preferential-attachment mechanism of pore

Evolutionary plasticity processes, such as ploughing and penetrating, widely exist in many geotechnical engineering applications. The simulation of these processes poses considerable challenges due to the occurrence of large deformation, unsteady nature of the material free surface, and inherent coupling between mechanical response and material geometries. This paper explores the possibility of simulating

The inclined retaining pile is an innovative excavation retaining structure free of internal braces. It can significantly reduce the cost and construction time of excavation. However, the stability of inclined-pile-supported excavations has not been well investigated. Discontinuity layout optimization was used to analyse the failure mode and the influencing factors of the stability of the excavation

A novel 3D contact detection algorithm for arbitrarily shaped, concave and convex blocks is presented. The algorithm comprises a new neighbouring search technique and a novel method to detect the true contact type between two neighbouring blocks, regardless of their shape. The new neighbouring search technique uses a convenient geometrical plane to reduce the number of searches and an efficient boundary

The infinite slope stability problem receives much interest in geotechnical engineering, as it can provide an initial assessment on the mechanics of shallow landslides. It is well known that natural soils exhibit spatial variability, with properties varying from point to point, and a trend of strength changing with depth. This paper will use a random field method to investigate the reliability of undrained

Porous brittle solids evidence complex mechanical behavior, where localized failure patterns originate from mechanical processes on the microstructural level. In order to investigate the failure mechanics of porous brittle solids, we outline a general stochastic and numerical microstructure-based approach. To this end, we generate random porous microstructures by level-cutting Gaussian random fields

Over the last 40 years, there have been several ship losses carrying granular mineral ores that are believed to have been caused by the sudden shifting of the cargo as a result of liquefaction. It is known that the initial moisture content during loading is important for cargo types which are considered susceptible to liquefaction. To limit the moisture content, the degree of saturation must be below

This paper develops an efficient algorithm that combines polynomial-chaos kriging (PCK) and adaptive radial-based importance sampling (ARBIS) for reliability analysis. The key idea of ARBIS is to adaptively determine a sphere with the center at the origin and radius equal to the smallest distance of the failure domain to the origin, also known as the optimal β-sphere, and only those samples outside

This study investigates the interaction process between grouted bolts and tunnel surrounding rock, and establishes an analytical model for deep tunnels reinforced with active grouted rockbolts of the convergence-confinement type. The rock mass is assumed to be elastic-perfectly plastic, obeying the Hoek–Brown criterion. The longitudinal displacement profile is introduced to represent the space effect

Red clay, an easily cracking lateritic soil, is extensively distributed in southern China. Cracked red clay slopes often show shallow failures under rainfall, which is challenging to reproduce by finite element methods. This study aims to examine how desiccation cracks and vegetation affect the shallow stability of a red clay cut slope during rainfall. Numerical models of the slope are created using

A closed form solution is developed to quantify the stresses that develop in polymer liners installed within pressure pipes, where the liner spans across a joint or ring fracture in the ‘host’ pipeline that is subjected to axial extension as a result of ground movements. The solution considers the zones of slip between liner and host pipe on either side of the joint that is opening. The expression

Water adsorption isotherm describes soils’ ability in retaining water under given relative humidity and isothermal conditions, and is frequently utilized to characterize soils’ engineering properties. Fundamentally, the water adsorption isotherm on soil external particle surface is the macroscopic manifestation of atomistic scale soil–water interaction mechanisms, including van der Waals, surface hydration

The response of pile groups and piled structures to vertical and tunnelling-induced loads is studied. A two-stage model is adopted that can efficiently consider external actions, greenfield tunnelling movements, superstructure stiffness, ultimate pile shaft and base stresses, pile-soil interactions in uniform or layered soils, and local soil behaviour (as either linear elastic, elastic perfectly-plastic

A decoupled ALE method is developed based on operator splitting technique and soil water two-phase mixture theory and applied to the seismic response analysis of subway station in saturated sand in this research. It is found that the Rayleigh damping coefficients have a remarkable influence on the deformation shape, the final floating, and the acceleration response of the underground structure, which

The commonly used finite element software does not provide a three-dimensional (3D) fluid-saturated element available for dynamic analysis of two-phase media, which extremely limits their advantages in solving complicated engineering problems. This paper develops a user element for 3D dynamic analysis of fluid-saturated porous media in ABAQUS based on the u-U formed equations. The dynamic governing

The prediction of failure load factor and stress distribution at limit state plays an important role in geo-technical engineering design. This paper develops a pseudo-lower bound numerical procedure for adaptive limit analysis of geo-mechanics problems governed by the Mohr–Coulomb failure criterion. Equilibrium equations for the residual stress are enforced in a weak manner, allowing the use of displacement-based

In recent years, underground pipeline leakage occurs frequently in urban regions, which seriously reduces the soil-structure stability in the vicinity of the leakage. In this paper, a numerical study about pipeline leakage-induced instability of adjacent excavation earth retaining wall (EERW) is carried out. To reflect the phenomenon of soil strength degradation when encountering leakage water, the

Accurate prediction of pore water pressure responses in soils is critical for predicting stability of a slope when subjected to rainstorms. Slope hydraulic model and soil hydraulic parameters have been widely used in prediction of pore water pressure responses under rainfall infiltration, but establishing a suitable slope hydraulic model and accurately identifying its parameters for a specific slope

The spatial variability of rockfill properties is the key factor affecting stochastic seismic responses. Herein, an efficient probabilistic analysis method for stochastic seismic analysis named the generalized probability density evolution method (GPDEM) is proposed and combined with the random field generated by K-L decomposition to evaluate the stochastic seismic responses of concrete-faced rockfill

The long-term stability of an underground deep cavity involves a lot of complex time-dependent mechanical processes. This paper presents an analytical approach for the post-closure behaviour of a deep spherical cavity inside a dilatant viscoplastic rock mass considering three stages: (1) excavation, (2) free convergence and (3) backfill contact and post-closure. The viscoplasticity is modelled by means

Fracture propagation in rocks is a complex thermal-hydro-mechanical (THM) phenomenon present in geotechnics, such as enhanced geothermal systems, CO2 sequestration, and shale gas exploitation. Numerical simulation is an essential way to study its mechanism. In this study, a pore-scale model combined with the lattice Boltzmann method (LBM) and the discrete element method (DEM) is developed, in which

The mitigation of surface wave is the primary concern in ground vibration isolation due to the energy of wave propagation in the soil being concentrated in the surface wave. Herein, a composite in-filled trench composed of expanded polystyrene (EPS) and concrete was proposed and arranged as a periodic structure. The surface wave attenuation zone of the proposed periodic composite in-filled trenches

This paper presents a series of finite element analyses to investigate the performance and reinforcing mechanism of geosynthetic-reinforced soil (GRS) foundations subjected to normal fault movement. Numerical and experimental results of unreinforced and reinforced foundations were first compared for model validation. Parametric studies were then conducted to evaluate the influence of soil and reinforcement

Shallow-buried structures are inevitably subjected to time-varying disturbances such as drilling and blasting, earthquake and tectonic activities. The work presented in this paper focuses on the transient responses of a shallow-buried cavity. Based on the wave function expansion method, the large arc approximation and the integral transform, the time-domain responses around a cylindrical cavity subjected

An improved version of the node-based smoothed point interpolation methods (NSPIMs) is proposed for coupled hydro-mechanical problems of geotechnical engineering. In the improved NSPIMs (I-NSPIMs), the polygonal nodal smoothing domains are estimated with area-equivalent circular domains. The smoothed strains over the circular nodal smoothing domains are then assumed to be linear, in contrast to the

This paper presents numerical treatments of elastoplasticity relations for a previously developed critical state two-surface plasticity model and its implementation into a bespoke finite element code as well as the commercial software Abaqus via the user defined subroutine, UMAT. The model is implemented with an efficient integration scheme based on the explicit modified Euler scheme with automatic

Presented here is a modular methodology for time-domain stochastic seismic wave propagation analysis. Presented methodology is designed to analyse uncertain seismic motions as an input, propagating through uncertain material. Traditional approach for uncertain wave propagation relies on models that include deep bedrock, local soil site, and their random process and random field information. Such models

A rigorous and practical solution aimed at accounting for the effect of groundwater in the assessment of bearing capacity of shallow strip footings in plane strain conditions has been developed using the method of characteristics. A steady water table in the foundation soil is considered and a bearing capacity factor Nγw to be used in the classical trinomial bearing capacity equation is introduced

To consider the shape effect of band prefabricated vertical drain (PVD), an elliptical cylindrical equivalent model of PVD-improved foundation including horizontal and vertical drainage is built, and then the analytical solutions of the excess pore-water pressure and the degree of consolidation under a combined vacuum pressure with time-dependent surcharge load are derived. For the elliptical cylindrical

Screw piles are efficient anchors to sustain large uplift loads and can be installed with low noise or vibration. Screw piles dimensions are currently increasing, renewing research interest to reduce the installation requirements (torque and crowd or vertical force). The Discrete Element Method (DEM) is an ideal technique to investigate the complex soil behaviour during screw pile installation. Different

In this study, an explicit three-dimensional discontinuous deformation analysis (3D-DDA) is parallelized. Using explicit contact force circumvents the open-close iteration and makes the global stiffness matrix block-diagonal. Post-judgment of contacts is split into two parts to unify the data access pattern, constant acceleration Newmark method is adopted to guarantee unconditional stability of time

This study investigates the multiscale roughness effects on hydrodynamic heat transfer (or heat transfer associated with water flow) in a single fracture, based on direct numerical simulations of fluid flow and heat transfer in fracture-matrix systems with or without secondary roughness considered. The simulation results show that the primary roughness controls the low velocity regions and the overall

This study proposes an efficient full probabilistic design method using an advanced Monte Carlo simulation (MCS) algorithm, so-called generalized Subset Simulation (GSS), for which a concept of design response vector is proposed. The proposed design response vector contains responses of all possible designs and is used to, simultaneously, explore failure domains of different designs. With the design

With the rapid development of subway, the ground movement induced by water and sand gushing occurs frequently in the process of tunnel construction. Existing research has not paid significant attention in the influence of sand inflow on the ground settlement and the development process of deep soil after water and sand gushing. Thus, the aims of the present study were: (i) to numerically explore the

This paper mainly investigates the effect of soil spatial variability on failure mechanisms and capacities of strip foundations under uniaxial loading on marine clay deposits with linearly increasing undrained shear strength using random finite element analysis. The soil spatially variable feature is characterised by a non-stationary random field where the ratio of the standard deviation and mean of

For the safety and serviceability of an existing underground structure due to a new excavation below, a soil-structure separation model based on subgrade reaction analysis is proposed to study the responses of the existing underground structure. Our proposed method can determine the soil gap formation and then predict the soil gap dimension. Our method's length and height of the soil gap agree well

The surrounding rock often show obvious rheological characteristics when tunneling in high geostress environment, accompanied by large deformation, slow convergence and increasing support pressure. “Yielding-resistance combination” support inspired by the concept of NATM is widely employed in squeezing tunnels which has been successfully implemented to control the large deformation in many high geostress

For quasi-brittle rocks, a novel micromechanics-based fractional friction-damage coupling model is presented by combining the fractional plasticity theory and the micromechanical formulations for cracked solids. The plastic deformation is stemmed directly from the frictional sliding along microcracks while the damage is related to the initiation and propagation of microcracks. These two dissipation

Influence of particle angularity on the suffusion in gap-graded granular soils remains unclear up to now. In this study, systematical numerical simulations that consider the particle shape as quasi-spherical polyhedra in different angularity are performed with the coupled discrete element method (DEM) and the computational fluid dynamics (CFD) approach. The suffusion of six gap-graded soil samples

In this study, Discontinuous Deformation Analysis (DDA) method is extended to simulate Soil-Water Characteristic Curve (SWCC) by considering both capillary water and bound water at the micro-scale. First, a simple and practical bound water model is proposed and incorporated into DDA program to simulate SWCC in the high suction range. Then, to prove the availability of the developed program, the extended

A mixing-locally polynomial Regression method and Global Sensitivity analysis – (MRGS) procedure is used in assessing foundation and abutment uncertainties of concrete arch dams. Latin hypercube sampling is employed for generating samples in the sensitivity analysis. The model consists of a typical 80 m high arch dam along with its foundation and abutments. A potentially movable rock wedge confined

Multidirectional shearing tests on soils in the laboratory suffer from drawbacks such as non-uniformity of stress and unknown horizontal stress of the specimen. As a promising numerical technique, the discrete element method (DEM) enables investigation of the responses of virtual granular samples under general loading conditions and provides ideal numerical results to overcome the aforementioned limitations

To understand the longitudinal structural deformation mechanism of shield tunnel linings, it is crucial to reasonably consider circumferential joints, especially their shearing deformation. Towards that end, first, the dislocation between lining rings caused by the differential settlement of an actual tunnel project in Shanghai was introduced in detail. Next, the longitudinal deformation model of shield

The concrete face slab is the primary anti-seepage component of concrete faced rockfill dams (CFRDs). Therefore, the seismic safety of the slab is an important issue. In this paper, the cohesive zone model and the explicit solution are expanded to conduct 3D seismic failure analysis of a CFRD. A combination of the generalized plasticity model of rockfill, state-dependent elasto-plastic model of soil-structure

Tapered piles have superior benefits over traditional cylindrical piles in resisting axial and lateral loads, being an economical alternative to cylindrical piles. When designing the tapered pile in soft or liquefiable soil, it is necessary to identify its buckling strengths. Notwithstanding, the buckling analysis of tapered piles considering nonlinear pile-soil interactions with geometric imperfections

High-pressure tunnels with reinforced concrete lining have been extensively utilized in project practice. This study aims at developing a complete hydro-mechanical numerical model of high-pressure tunnels with emphasis on the interaction between lining and rock mass. In the model, a fully hydro-mechanical coupled formulation for saturated porous media is first established. A virtual element approach

Soils are inherently anisotropic, which may significantly influence their mechanical behavior and the performance of related geostructures. In this study, the response of strip footing on anisotropic sand was investigated using a J2-type deformation model coupled with state-dependent dilatancy and fabric evolution. The capability of the model was validated by simulating several element tests and a