Geomaterials containing fissures such as some sedimentary rocks often exhibit a bimodal pore size distribution, and they are also inherently anisotropic due to the distinct bedding planes. Hydromechanical modeling of solid deformation and fluid flow of such geomaterials remains a significant challenge. In this paper, we have developed a unique anisotropic double porosity elastoplastic framework to

Piles are commonly used in wharfs and offshore platform foundations. The coupled effects of current scour and dynamic load can reduce the non-deformability of a pile-soil system and ultimately lead to structural instability of structures. This paper develops a simplified method to study the dynamic interaction of layered saturated soils and piles under current scour conditions. Fundamental solutions

Before this study, no analytical models had been made available for describing the behaviour of plane geostructures subjected to thermal and mechanical actions. This knowledge gap notably represented a limitation for investigations about the behaviour of so-called energy geostructures, which are subjected to the considered actions due to their geothermal heat exchanger and structural support roles

The High Strain Dynamic Test (HSDT) offers an alternative approach to the conventional static load test for estimating the axial capacity of helical piles due to its faster implementation and potential cost savings. In this paper, a mathematical model developed by Clough & Penzien that simulates the force-time response at the top of a pile with uniform cross-section subjected to a hammer impact is

Non-cohesive granular materials exhibit fabric-induced anisotropy of small-strain stiffness. The stiffness anisotropy is often measured using dynamic wave measurements in the laboratory. It is widely accepted that elastic wave velocities are influenced by stress state, while the role of particle shape in the wave velocity anisotropy, and thus the stiffness anisotropy, has not been fully understood

This paper investigates the time-dependent response of laterally loaded single piles and pile groups embedded in transversely isotropic saturated viscoelastic soils. The solution for single piles subjected to lateral loads is solved by the coupling of the boundary element method and the Timoshenko beam theory. In the analysis of the pile group, the interaction between piles is taken into account and

Cutoff walls are widely used as in-situ vertical barriers to control pollution plumes migration in aquifer. A two-dimensional analytical model for the transport of organic contaminants through a layered subsurface system with a cutoff wall is developed. The model considers a coupled advection-dispersion-adsorption-degradation process in the whole system and a non-uniform concentration distribution

Although tunnels are vulnerable to Permanent Ground Displacement (PGD) due to a fault crossing, studies in assessing this intersection are limited, and most of the existing studies have focused on fault movement parallel to the tunnel. A series of numerical models with the Finite Element Method is applied here to evaluate the behavior of tunnels and reverse faults intersections. The numerical modeling

An analyzing program SMAS based on digital image processing technique is developed for quantifying soil microstructure. By using SMAS, a series of geometrical and morphological indexes of soil particles/pores in microscale can be quantitatively determined. Three examples of using SMAS to quantify the microstructure features are shown. The analyzing results indicate that the developed program can effectively

Based on a self-developed adaptive finite element limit analysis (AFELA) code and generalized Hoek-Brown (GHB) failure criterion, the footing-void system subjected to eccentric load in rock masses is investigated. The research emphasis of this study is on quantifying the effect of the load eccentricity and voids on the ultimate bearing capacity of footings. Predictions of footing ultimate bearing capacity

Vibrations propagating underground may have harmful effects on adjacent buildings and human health. Recently, the notion of phononic crystals has been introduced and applied to isolate vibrations below the ground. In this paper, considering the viscoelastic material model, the complex band diagrams are suggested to analyse the transportation of vibrations in the composite foundation consist of soil

In recent years, the vulnerability and protection of subsurface structures under blast loads became a fundamental issue in terms of security (loss of lives and structural damage). A tunnel can be considered as an underground shelter and is a crucial structure owing to its conservative nature against explosions. This study is performed to obtain a further understanding of surface explosion influence

This paper analyses with a sophisticated numerical model the long-term phenomenology induced by Earth Pressure Balance tunnelling in compressible, low permeability soils. The complex soil-structure interaction determined by the EPB technology is analysed with a three-dimensional model that closely reproduces the sequence of face pressurisation, excavation, lining installation and tail grout injection

This study provided a feasible approach for more accurate analysis of rock slope stability under rainfall infiltration. To quantitatively analyse the influence of rainfall on slope stability, we attributed the influence of rainfall on slope stability to the change in pore pressure and the decrease in rock strength due to the effects of water-induced weakening. The variation law of the mechanical behaviour

In this paper, a fully coupled numerical model is developed based on the X-FEM technique to simulate the reactive acid transport in fractured porous media. The porous medium consists of the solid and fluid phases, in which the fluid phase includes water and acid components, and chemical reactions can be occurred between acid component and solid phase at the solid–fluid interfaces. The governing equations

This paper presents a novel analytical solution for one dimensional consolidation system of unsaturated soil incorporating impeded drainage boundary conditions. Through diagonalizing the coefficient matrix, the consolidation system is firstly transformed into a diagonal one with respect to a new variable vector. Then, using the methods of eigenfunction expansion and undetermined coefficients, the analytical

The actual settlement of foundations is one of the main topics in geotechnical engineering due to the complex soil-foundation interactions and nonlinear behavior of subsoil. To consider soil behaviour properly, continuous records of a cone penetration test (CPT), which have been rarely considered in the literature, can be applied to estimate the settlement of a shallow foundation (St). In this study

A novel model combined with fractal theory and the discrete fracture network (DFN) model is proposed to simulate radon migration in fractured media. In the novel model, the fracture center and length distribution are determined by a first-order model, and the fracture orientations are modeled with the von Mises-Fisher distribution. The model is further developed into a computer software that can calculate

Seismic waves have significant effects on the stability of geotechnical engineering projects. However, only a small number of studies have focused on the seismic stability of tunnel faces. Using the kinematic approach of limit analysis, this paper conducts a seismic analysis to evaluate the three-dimensional stability of the tunnel face. A three dimensional rotational mechanism is introduced to describe

This paper discusses the settlement characteristics of a historical building near the corner of a supported excavation made in soft soil during the construction of a subway. Measurements from the study site at Daliang Station, Foshan, China are analysed, and the effects of partition walls are explored. The complexity of the corner effects of braced excavations is considered, and deformation forms and

A series of monotonic and cyclic triaxial shearing tests on Toyoura sand are simulated by discrete element method (DEM) incorporating rolling resistance. The input parameters are calibrated against laboratory triaxial test data considering different initial states and monotonic loading paths. The calibrated DEM model successfully captures the density and stress dependency of sand behavior under both

This study presents an analytical framework of limit analysis for the ultimate load of unsaturated soil slopes with the non-associated plasticity. The method of characteristics combined with boundary value problems is applied to build the slip line field that satisfies the stress boundary and the velocity boundary simultaneously. According to the proposed approach, a value of the ultimate load of slopes

Accurate prediction of the state-dependent shearing behaviors of sand in a rational way is a challenging task of the development of constitutive models. In the present study, a deformation type model is proposed based on a modified Duncan-Chang hyperbolic equation, which provides a simple and efficient way to characterize the stress–strain relationship. The hyperbolic equation is improved to tackle

The measurement or estimation of the permeability of soft sediments remains a difficult albeit necessary task for several geotechnical applications, such as land reclamation and tailings management. This note presents a new method for determining the two parameters (the multiplier and power) of the power permeability function for high water content sediments, using settlement data from a column experiment

In this study, 3-D particle-based discrete element methodology (DEM) is applied to investigate the mechanical and failure characteristics of fissured marble specimens in true triaxial compression with a new loading stress path. The new loading stress path is controlled by two loading parameters: the initial confining pressure σ0 and the loading stress ratio b. In the numerical investigation, eighty-eight

Mechanical properties of crystalline rock are greatly affected by its micro-structures which are characterized as highly-interlocked polygon grains and presence of micro-defects. Due to insufficient consideration of micro-structures in crystalline rock, previous simulations using discrete element method (DEM) cannot realistically reproduce the mechanical properties of crystalline rock including crack

Differences in the effective thermal conductivity (ETC) between measurements and models may be attributed to the limited ability to capture microstructural information of geomaterials. Today, computed tomography (CT) technology offers unprecedented access to such information, particularly for sands. Since a sand can be represented as a contact network made of nodes (particles) connected by edges (contacts)

With the rapidly increasing capacity of renewable energy production, the volatile nature of, e.g., wind and solar power necessitates solutions for storing excess energy. A finite-element model for simulating a geomembrane energy storage system is developed, in order to aid the development of the system and provide first insights into the performance of the system. Conceptually, energy is stored by

A bounding surface model in general stress space is formulated for soft rock subjected to drained and undrained condition. Specifically, a UYC bounding surface is defined based on unified yield criterion by introducing bounding surface plasticity, and it can degenerate to a bounding surface adopting Mohr-Coulomb criterion or Twin-shear criterion; a UYC loading surface that is similar to the UYC bounding

In practice, horizontal drains are often arranged at certain depth in dredged clays to accelerate the consolidation process in layered clay-sand reclamation subjected to surcharge preloading, and the layout of horizontal drain is usually determined based on a trial-and-error procedure. Based on the transfer matrix approach, a semi-analytical solution is derived using Laplace transform and its numerical

The one-dimensional (1D) rod model, which is used in several pile dynamics applications, has two main simplifying assumptions: only vertical reaction is considered and excitation on the pile top is treated as uniform. These two simplifications negatively affect its application in pile integrity tests, especially for large-diameter piles. To overcome these two limitations, a new non-uniform axisymmetric

The behaviour of cemented granular material is complicated by the fact that the eventual cemented properties depend on the conditions under which cement hydration (curing) takes place. There are a number of situations in industry where granular materials are mixed with small quantities of cement and deployed in highly transient curing environments. Understanding and predicting the responses in these

Seismic stability of slopes reinforced with soil nails has been traditionally investigated by two-dimensional limit equilibrium method. In this paper, the strength reduction method in combination with the kinematic approach of limit analysis is employed to assess the factor of safety (Fos) of slopes reinforced by soil nails using the three-dimensional rotational failure mechanism. The pseudo static

In this work the anisotropic model for clays SANICLAY proposed by Dafalias and Taiebat (2013) is reformulated within the framework of hyper-elastoplasticity. The model, called SANICLAY-T, is fully defined by two scalar potential functions, the free energy and the rate of dissipation. It is first presented in the triaxial space and then generalised in the multiaxial one. The model reproduces exactly

The shrinkage swelling phenomenon of clayey soils is affected by Soil-Vegetation-Atmosphere (SVA) interactions and can cause severe structural damage to lightly loaded constructions such as residential buildings. A soil-atmosphere interaction method was primarily presented along with a coupled hydro-thermal soil model. This approach was established to determine primarily, the natural time variable

This study presents a FEM-BEM coupled method to research the dynamic response of a fixed-head pile group in multi-layered transversely isotropic media subjected to transient horizontal loadings. Piles are discretized into finite elements on the basis of Euler-Bernoulli model. Fundamental transient solutions of the media derived by the analytical element method are taken as kernel boundary element functions

A tensor-based approach is adopted to investigate the evolution of stress variability within granular media based on DEM simulations of both cyclic and static liquefactions. The bulk stress dispersion is evaluated using the effective variance of the entire stress tensor field and the local stress fluctuation is quantified by the Euclidean distance between the stress tensor of individual particles and

The flat-jointed (FJ) contact model implemented in the particle flow code resolves the long-standing issue of the code producing unrealistically low ratios of uniaxial compressive strength (UCS) to direct tensile strength. Despite the improvements introduced with the FJ model, an FJ sample calibrated to the UCS still produces a crack initiation stress much lower than the expected value of approximately

The cyclic behavior of silty sands is complex in that it depends not only on packing density and confining pressure but also on fines content. How to properly model the behavior is emerging as an active area of research in geomechanics and engineering. This paper presents an attempt to formulate a critical state-based constitutive model for describing the cyclic loading behavior of sand with varying

The geotextile encased stone column has been numerically modeled with the DEM gravel specimen wrapped by the finite-element shell structure. The irregular shape and size distribution of gravels have been simulated according to the experimental data using the rigid block module in PFC. The geotextile encasement has been modeled using the geogrid elements in FLAC3D. The complete stress–strain behaviors

This paper introduces a simplified smooth rock reinforcement modeling approach based on the 2D combined finite discrete element method (FDEM). The goal is to facilitate modeling the end grouting process and the full grouting process of rock bolts reinforcement, and to improve further understanding of the interaction between bolt, grouting, and host rock based on material mechanical behavior. The study

The available theoretical models for evaluating seismic active earth pressures are limited to plane strain analyses and linear failure criterion. To fill this research gap, with a combination of the kinematical approach of limit analysis, the spatial discretization technique as well as the pseudo-static approach, this work develops a discretized three-dimensional failure mechanism of sloping backfills

Offshore wind turbines (OWT) are generally founded on piles or gravity base foundations. Up to now, there is a lack of validated and standardized analysis procedures for such foundations, especially for the serviceability limit state, i.e. for the prediction of accumulated deformations. In order to gain experience on the behaviour of a OWT gravity base foundation under typical offshore loading conditions

Thermo-active piles are capable of providing both structural stability as foundations and low carbon heating and cooling as ground source heat exchangers. When subjected to heating or cooling, the soil surrounding the pile restricts its expansion or contraction, giving rise to thermally-induced axial stresses, which need to be considered during design. Previous numerical studies often assume axisymmetry

Recent advances in tire recycling technologies coupled with increasing global environmental awareness have resulted in several new products derived from scrap tires, including tire-derived aggregate (TDA). TDA is an inexpensive engineered lightweight backfill material with excellent geotechnical properties, produced by shredding scrap tires into sizes ranging from 12 mm to 305 mm. This paper examines

Properly modelling the particle breakage characteristics is important for crushable soils such as carbonate sands, rockfills and rail ballasts. According to the generation mechanism, particle breakage was decomposed into two parts: compression-induced particle breakage associated with the increase of mean effective stress and shear-induced particle breakage related to the change of shear stress ratio

In geotechnical engineering, multiple failure modes exist, and any one can contribute to the failure of a system. System reliability is related to both the probability of failure of each failure mode and the correlations between them, which is obviously different from the reliability analysis of a single mode. This paper focuses on system reliability analysis for geotechnical engineering application

The heterogeneity of natural rock affects its fracture behaviour resulting in a variation of rock strength. To investigate the sensitivity of damage response and failure strength across rock samples numerical simulations are performed with random realizations of the Young’s modulus. As a test case, we consider a rock specimen with a pre-existing 3-D surface flaw under uniaxial compression. To test

Hydraulic fracturing technology developed to enhance the production of oil and gas in underground reservoirs has expanded to other applications. As the exploitation of underground resources moves deeper, traditional hydraulic fracturing models based on linear elasticity may be inadequate to predict the characteristics and geometry of hydraulic fractures at great depth, which are usually under conditions

We employ a hierarchical multiscale modeling approach to investigate the transitions of localized deformation patterns in high-porosity sandstone subjected to sustained shear to understand their underlying physics. The multiscale approach is based on hierarchical coupling between finite element method (FEM) with discrete element method (DEM) to offer cross-scale predictions for granular rocks without

In this paper, we introduce the μ(I) rheology into the traditional depth-averaged continuum framework and include the effect of grain size when describing the normal stresses of a flowing avalanche. We also develop a set of experimental installations for granular flow and use the installations to simulate laboratory avalanches: sand initially accumulates in various geometries, is then released and

In this paper, a novel elastoplastic solution is developed for the undrained expansion of a spherical cavity in overconsolidated soils, with the aim of providing a mechanical model for the interpretation of cone penetration tests in overconsolidated soils. The well-established unified hardening (UH) model is adopted in the present solution to represent the unique mechanical behaviors of the overconsolidated

Free fall projectiles have been used in offshore engineering to determine in-situ undrained shear strength profiles of near-surface soft soils from accelerations recorded during penetrating. In doing so, however, only the equation of motion in the vertical direction has been formulated with the vertical acceleration by assuming vertical impact and penetration. In this study, the governing equations

In this study, computational efficiency and performance of the smoothed point interpolation methods (SPIMs) in coupled problems of geomechanics are examined and compared with those of the standard linear finite element method (FEM). In the SPIMs, the problem domain is first discretised using a triangular background mesh, and the smoothing domains are then constructed using the cells of the background

A displacement back analysis algorithm is developed, considering the time-dependent effect of the rock mass. It can map spatially distributed the first elastic modulus (E1), viscidity coefficient (η1), and the second elastic modulus (E2) of the Kelvin-Voigt viscoelastic constitutive model (VCM) and the Poynting-Thomson VCM in a rock mass by fusion of the observed displacement data from the excavation

This paper presents new fully-coupled analytical thermo-poroelastic solutions, introducing four new components to the traditional Local Thermal Non-Equilibrium (LTNE) theory: thermo-osmosis; thermal-filtration; heat sinks due to thermal expansion of the pore fluid and the solid phase; and vertical confinement. Thermo-osmosis, thermal-filtration, and fluid dilation are found to have very different effects

A numerical investigation on the effects of inter-particle friction and particle sphericity on isotropic compression in real-shaped sand assemblies is carried out using the discrete element method. Real-shaped sand assemblies are generated in terms of the cumulative distribution of the shape descriptor (sphericity) of real sand particles. The mechanical behaviors of compression are quantified in terms

In this study, pseudo-static and dynamic analyses were performed for reasonable earthquake-resistant designs of soil-pile systems. The emphasis was on evaluating the effect of bedrock acceleration on the earthquake-resistant design of soil-pile systems in sand. Three-dimensional (3D) numerical analysis was performed at different bedrock accelerations and soil densities. Numerical solutions were verified

During drilling and blasting construction, a water inrush can be caused by damage to a water-resisting rock mass. Tunnel water inrush is a common anthropogenic geological hazard in engineering. The traditional finite element method (FEM) is less accurate in dealing with large deformation problems, and the Discrete element method (DEM) cannot realize engineering scale operation. In this study, the Johnson-Holmquist

Bearing capacity of offshore pipe pile is difficult to predict due to the soil variability and uncertainly associated with the field investigation and soil-pile interactions. This paper examines factors affected prediction errors of bearing capacity based on the in-situ cone penetration test (CPT) results for pipe piles. The uncertainly of transformation, geomaterials and field experiments were characterized