In this study, the dynamic response of a concrete-filled tapered Fiber Reinforced polymer (FRP) tube pile, embedded in a transversely isotropic viscoelastic medium, undergoing axial vibration is investigated. The soil adjacent to the pile comprises of an inner nonlinear zone and an outer linear viscoelastic zone. The tapered pile is discretized into small elements, and the displacements and stress

To investigate the crack propagation and failure mechanisms of brittle materials in the Brazilian tests, an acoustic emission (AE) simulation was implemented in the Discrete Element Method. AE location and magnitude were monitored during the whole process of the simulation to detailedly observe crack initiation and associated AE evolution. Moment tensors were directly calculated by the forces and motions

The applicability of the classic Terzaghi or Biot effective stress laws to fractured rocks is not clear. Based on discrete element models, bulk modulus method and equivalent strain method are presented to determine the effective stress coefficient of saturated fractured rocks, and were examined with the regular fracture network I. Two types of discrete fracture networks, including regular and random

When new metro tunnels undercrossing existing tunnels, deformation is inevitably caused in the stratum and the existing structures. However, the calculation results by conventional prediction methods often bring large errors compared to measured or simulated data because the complex influences of the stiffness of existing structures is always neglected. According to the equivalent layered method, an

System reliability analyses are necessary for geosynthetic reinforced soil slopes because of the uncertainties associated with design parameters and complicated interaction between geosynthetic reinforcements and soil. This paper presents a new method for system reliability analysis of reinforced soil slopes considering local failures of reinforcements based on total probability rule with a typical

Rockfill materials undergo additional deformation when immersed in water under constant-stress conditions. This phenomenon caused by flooding is called wetting deformation. Researchers have investigated wetting deformation via many factors through laboratory tests on scaled materials. However, the size effect on wetting deformation has seldom been studied due to the limited size of test equipment.

The bearing capacity of shallow foundations under static loads has been widely studied by various authors. In contrast, the bearing capacity under dynamic loads has been solved indirectly by adopting an equivalent pseudostatic approach or by means of reduction coefficients. The study of the problems related to cyclic loads has focused mainly on the behavior of granular soils. However, in the case of

The high-energy rate of shock waves, as an important part of explosion energy, plays a significant role in the mechanism of rock fragmentation. This energy rate and the mechanism of rock fracturing are controlled by several parameters related to both the explosive charge and rock mechanical properties. In this study, the mechanism of rock fragmentation due to blast-induced shock waves in a single blasthole

The active earth pressure evaluation was typically conducted assuming dry backfills and/or two-dimensional collapse mechanisms. In practice, retained slope collapse usually shows a three-dimensional (3D) feature and soils are usually unsaturated. The present work develops a framework for evaluating the 3D active earth pressure under transient unsaturated flow conditions. The framework is implemented

Pre-existing joints have a significant influence on the geometry of the fracture network induced by hydraulic fracturing. Understanding the interaction between hydraulic fractures (HF) and pre-existing joints is of great importance to optimize the design of hydraulic fracturing operations in many applications. A three-dimensional hydro-mechanical coupled lattice-spring code was employed to investigate

This paper presents a study on mitigating the degradation of ballast by placing an under-sleeper rubber pad (USP) beneath a sleeper. Large-scale track process simulation apparatus (TPSA) tests have been carried out on ballast assemblies (with and without USP) subjected to cyclic loadings. Numerical modelling has been performed using a coupled discrete-continuum modelling (coupled DEM-FDM) approach

A stability analysis of slurry-supported trenches in horizontally layered cohesive-frictional soils by using the kinematical approach of limit analysis is presented. To ensure the kinematical admissibility, the failure surface in the formulated multi-block rotational mechanism was composed of several segments of logarithmic spirals with a same rotation center. To account for varying soil properties

Analytical methods based on linear elasticity have been used to model the dynamic response of foundations. These solutions commonly assume that soils are isotropic and elastic. Incorporation of anisotropy and the two-phased nature of soils (solid skeleton with pores filled with water) is important in the study of dynamic response of foundations. This paper presents the explicit analytical solutions

The aim of this article was to optimize the shape and modulus of T-shaped deep cement mixing (TDM) and conventional deep cement mixing (DCM) columns for supporting embankment over soft soil. Objective of optimization is minimizing the column costs and differential settlement while maximizing the stress efficacy. A 2D axisymmetric numerical modelling was employed to investigate the behavior of TDM and

The present study presents a novel procedure to assess the seismic slope stability, using the finite-element upper-bound method combined with the pseudo-dynamic approach. A pioneering work is performed to incorporate the pseudo-dynamic accelerations into the finite-element upper-bound analysis which combines the advantages of upper bound and finite element methods. The finite element method is principally

The behaviour of suction anchors subjected to combined average and cyclic loads in soft clays is an essential consideration in their design. A new numerical computation method was developed based on a stiffness degradation model for soft clay that was proposed by performing a series of undrained cyclic triaxial tests and embedded in the ABAQUS software package by encoding the USDFLD subroutine and

The effect of particle shape on particle breakage is investigated through triaxial tests on sand assemblies mixed with non-spherical agglomerates using the discrete element method. Mixed assembly is generated in terms of cumulative distribution of sphericity of real sands. Comparable macro-mechanical results are found between DEM and experimental observations, including non-linear stress-strain relationship

In this study, finite element limit analysis (FELA) is employed to investigate the undrained seismic bearing capacity of strip footings placed on two-layered slopes. Upper bound theorem (UB), lower bound theorem (LB) and adaptive meshing technique were used in parametric studies to investigate the effects of various factors on seismic bearing capacity Ncs and failure mechanism, especially the seismic

Calculation of derivatives on discrete measurement data with unequal intervals is often required in geotechnical engineering, such as interpretation of stiffness reduction curve of soil from pressuremeter test data, pile lateral responses from inclinometer data. Such a task is however tricky and challenging, because a small error or noise in the measurements may amplify and lead to huge fluctuations

This paper proposes a 3D model for analyzing the rockfall trajectory within the framework of contact mechanics and rigid body dynamics, focusing on arbitrary shapes of the falling rock and terrain. Firstly, the sphericity and the concavity and convexity are defined to quantitatively describe the overall shape and local appearance of often-observed falling rocks, respectively. A generation algorithm

In this study, the three-dimensional discrete element method (DEM) is used to model the unsaturated triaxial test at a low-stress state. The contact model, which considers the matric suction of soils as well as the contact area among particles, and the flexible boundary condition are proposed. Prior to the simulation for the unsaturated triaxial test, we identify the effect of them on the numerical

A micromechanics-based plastic damage model including localised failure is proposed in the present work for heterogenous materials which can be treated as a porous matrix reinforced by mineral inclusions. This model explicitly considers the influences of pores and inclusions volume fractions, also the solid phase dilatancy on the overall mechanical performance. The induced damage in solid phase is

Drill and blast method is mostly used method for excavation of tunnels throughout the world. This tunneling method involves the use of explosives. Compared with bored tunneling by Tunnel Boring Machine, blasting generally results in the development of a blast-induced damaged zone around the tunnel boundary. Theoretically, the presence of this zone, with its reduced strength and stiffness, will affect

Particle morphology is an inherent characteristic that has a significant influence on breakage behaviors of natural sands. Based on X-ray micro-computed tomographic scanning and image-processing, the three-dimensional (3D) particle surfaces of natural sand particles were first reconstructed by the spherical harmonic (SH) analysis. The traditional morphological parameters of the particles, including

This study aimed to investigate the stability of multi-stage drained and undrained slopes considering the spatial variability in soil properties. A bivariate random field was adopted to characterize the spatial randomness in soil strength parameters of each stage of soil slopes. The random field was then incorporated with the finite element method to obtain the factor of safety (FS) and evaluate the

The present study investigates the influences of spatial variability and randomness of the soil strength parameters on the load-settlement response of a strip footing placed on a geocell-reinforced soil slope by combining finite difference method with random field model. Both isotropic and anisotropic random fields of lognormally distributed soil friction angle are generated with the utilization of

Experimental water retention curve (WRC) obtained under constant volume (isochoric) conditions is crucial in the coupled hydro-mechanical formulation of unsaturated soils and for studying the role of void volume changes on the water retention behaviour of porous media. Experimental WRCs currently available in the literature are often unsuitable for this purpose since they include the effects of change

The stability of a dike is influenced strongly by its water content, via both changing its weight and strength. While safety calculations using both analytical and numerical methods are well studied, the impact of surface boundaries exposed to natural conditions is rarely considered, nor is the fact that this surface is covered in vegetation and is susceptible to cracking. This paper presents a numerical

A scattering problem of a plane dilatational wave disturbed by a lined tunnel with an imperfect interface embedded in an infinite unsaturated poro-elastic solid is investigated. By means of the Helmholtz theory and the wave function expansion method, the corresponding displacements and stresses are obtained in terms of the wave functions, where the coefficients involved are determined by solving a

The exploration and production of unconventional reservoirs, such as tight-gas sand, gas and oil shales, and geothermal deposits, require hydraulic fracturing treatments to increase reservoir permeability and enhance its production. However, the presence of natural fractures alters hydraulic fracture propagation through the rock formation. This interaction may lead to complex fracture networks, which

Quantitative assessment for the efficiencies of check dams is necessary for the purpose of reducing the risk of potential debris flow disasters. In this paper, an improved finite difference model is adopted to assess the efficiency of the check dam in Dagou debris flow gully, Gansu Province, China. Unlike other numerical models, the improved model can simultaneously consider bed entrainment and the

The presence of cracks in soil slopes is of major concern to researchers and engineers, as this phenomenon is typically considered to be an early indication of instability and potential landslides. In this study, the kinematical approach of limit analysis was applied to evaluate the three-dimensional (3D) stability of soil slopes with pre-existing cracks and the reinforcement effects of piles. A vertical

In this publication the u-w finite strain formulation is enhanced with a Generalized Plasticity model for sands. The new model is numerically solved using an Optimal Transportation Meshfree approach that is best suited for numerical analysis at finite strains. This new model allows to capture the hydro-mechanical response under large deformations of a saturated sand like soils where acceleration of

In this work, the Finite Particle Method (FPM) which is a typical meshfree particle method is formulated for static deformation and plastic flow problems. The novel formulation utilizes the Lagrangian-type kernel, which guarantees the method being free from the tension instability. A pseudo-viscosity is introduced into the particle system to prevent the hourglass phenomenon in the numerical procedure

This paper proposes a large-strain consolidation model that can consider radial transfer attenuation of vacuum pressure. In order to facilitate the solution, this proposed model is rewritten to take hydraulic head as the independent variable that can reduce the computational complexity. The universality of the proposed model is discussed based on the comparisons with several existing typical models

For effective applications of the adaptive management approach, inverse analysis procedures are used to update model parameters based on observations made during early stages of construction projects. These updated parameters are then used to compute the responses at later stages. This paper describes the inverse analysis of lateral wall deformations from a deep supported excavation in Chicago using

This paper presents a finite beam element method (FBEM) for analyzing the behavior of a two-pile foundation under eccentric and inclined loads located at sloping ground. A simplified physical model for the two-pile foundation is presented by dint of the strain wedge technique and FBEM. The emphasis is on establishing an element stiffness matrix, taking the P-Δ effect, the strengthening effect on the

Electro-osmotic consolidation can be used as a valid and innovative technique for ground improvement. Considering the limitation of previous studies that layered soil heterogeneity was not taken into account, this paper presented an analytical model for one-dimensional(1D) electro-osmotic consolidation of double-layered soil, and a computer program of fully explicit solutions for excess pore pressure

In this study, reliability and sensitivity analyses were employed to investigate the effects of a weak interlayer on tunnel face stability. Due to the irregular geology process and the movement of tunnelling machine, the situations of weak soils encountered during tunnel construction are complex and variable. To address this problem, this paper adopted reliability and sensitivity analysis to evaluate

Load-shedding culvert is a new rigid culvert type to improve the performance of load reduction method. This study is to analyze the effect of vertical earth pressure on the top of load-shedding culvert through analytical model. The proposed analytical solutions are validated by the numerical results and laboratory measurements. Then, using the verified analytical model, a series of parametric studies

The objective of this paper is to investigate how the non-stationary features of soil properties affect the stochastic result of bearing capacity of embedded shallow foundations. Undrained shear strength was modelled as a non-stationary random field with mean value increasing with depth. A nonlinear finite element analysis combined with random fields generated by the Spectral Representation Method

A multi-field model is proposed to study methane oxidation in landfill covers, especially its temporal and spatial variability. The proposed model consists of water-gas two-phase flow, multi-component gas flow, heat transfer, and biochemical reaction modules, and is solved using OpenFOAM based on the finite volume method. Applying this model, the coupled effect of gas diffusion, temperature and oxidation

A one-dimensional thawing process of frozen soil under a uniform initial temperature and a step increase of boundary temperature is investigated. The classical thaw consolidation model developed by Morgenstern and Nixon is extended by including unfrozen water in frozen soil and time-varying loads under two types of drainage boundaries. It is proven that the thawing front advances in proportion to the

This paper develops an analytical approach to estimate the long-term load-displacement behaviors of jacked piles in clayey soils. Apart from considering the effects of pile installation, subsequent re-consolidation and loading, the proposed approach properly considers the effects of soil aging on the long-term behavior of the surrounding soil so as to determine the load-displacement response of the

The two-liquid mixing grouting method of quick-setting slurry and its time-dependent viscosity characteristics lead to an uneven distribution of viscosity in the slurry diffusion zone. At present, there still lacks reasonable and effective slurry-water interaction analysis method to reveal the diffusion behavior of quick-setting slurry in dynamic water. Therefore, a Sequential Diffusion and Solidification

A well-known problem which arises in local damage models is that they suffer from mesh dependence and strain localization. In this study, we employ the non-local implicit gradient damage formulation for mesh sensitivity analysis of brittle materials. The basic concept of the non-local implicit gradient model is that the strain at a given point depends not only on the strain at that point but also on

The location of total seismic earth force is assumed to act at 2/3 of the depth of the wall height, which is reasonable for a homogeneous backfill using MO approach. However, such an assumption is questionable for earth pressures with nonhomogeneous backfills using the modified pseudo-dynamic approach.

In the present work, a methodology for setting up virgin stress conditions in discrete element models is proposed. The developed algorithm is applicable to discrete or coupled discrete/continuum modeling of underground excavation employing the discrete element method (DEM). Since the DEM works with contact forces rather than stresses there is a need for the conversion of pre-excavation stresses to