Backward erosion piping (BEP) is a type of internal erosion that significantly contributes to internal erosion being a leading cause of levee and dam failures, second only to overtopping. Despite its significance, very few numerical or analytical tools exist for assessing the progression of backward erosion pipes. Further, existing tools do not automatically refine the mesh near the pipe tip, nor do

Face support pressure is a crucial index to guarantee the stability at the earth pressure balance (EPB) shield tunnel face. Based on the limit equilibrium theory and the failure pattern observed in existing model tests, a novel three-dimensional failure mechanism is proposed to consider the evolution of failure pattern in dense sand stratum. The failure zone is divided into two parts: a failure slip

Developing an accurate and efficient forward model of the dynamic response of pavement structure is of great significance for obtaining the design parameters of the layered pavement structure through an inverse calculation based on the measured pavement data. However, the existing algorithms rarely consider the interlayer contact. Based on the traditional spectral element method (SEM), this study proposes

A lower bound (LB) axisymmetric limit analysis formulation is presented for Mohr-Coulomb materials using finite elements and semidefinite programming (SDP). The details of the application of SDP to the axisymmetric LB finite element method for Mohr-Coulomb materials are described in this paper. Through the use of the SDP, the axisymmetric Mohr-Coulomb yield criterion can be directly applied in its

This paper presents a numerical finite strain solution for a circular tunnel in Mohr-Coulomb and generalized Hoek-Brown strain-softening rock masses. By approximating the differential equations with a difference method in the deformed coordinates, an efficient procedure is presented to calculate the displacements and stresses. The proposed solution is verified by another numerical method for both

The rainfall-induced earth slope instability is time-dependent as a result of the infiltration process. In order to cater for the uncertainty of geo-material parameters, we conduct a time-dependent reliability analysis of the rainfall-induced landslide, which incorporates discretizing the stochastic process of rainfall infiltration, assigning instantaneous landslide limit state functions at discrete

In this paper, using the upper bound shakedown theorem by means of the displacement finite element method and nonlinear programming, a numerical method is proposed to obtain the shakedown limit of strip footing under repeated loading. Shakedown analysis is a powerful method that provides the possibility to determine the shakedown limit of a structure. The shakedown limit of a structure under repeated

A thermal cone penetration test (T-CPT) with heating and cooling is suggested for recording temperature changes at a pause in penetration [R3-5], serving as an efficient method for the identification of soil thermal properties. A numerical model for the one-dimensional heat conduction problem is proposed to simulate a T-CPT with considerations of [R3-6] the probe size and heating/cooling periods. Verifications

The Hybrid Lattice/Discrete Element Method is proposed for Bonded Block Modeling of rocks. The method is a combination of the Rigid Body Spring Network Lattice Model with the Discrete Element Method. The main advantages of the new method are: (i) it operates based on either a homogeneous or heterogeneous material assumption, with heterogeneity being represented by means of the Weibull probability distribution

The stress path during underground excavation is critical to the mechanical response of rock masses, and the excavation effects in front of a tunnel face cannot be ignored. In this study, a realistic stress path model was built to capture the actual behaviour of the surrounding rock during the entire excavation process. The key technical steps of the two-dimensional excavation simulations with this

Numerical simulations of pile installation in sands require advanced constitutive models which are able to predict the mechanical behaviour of soils in a wide range of soil stresses under different loading conditions such as cyclic and monotonic loadings. In this paper, an elasto-plastic constitutive model within a double hardening framework is described which is capable of reproducing the mechanical

This paper presents a model for rainfall-induced shallow landslides, revealing the failure mechanism from initiation of instability to final flow failure. The onset of slope failure occurs with a completely formed plastic shear band that is triggered by a rainfall-induced increase in pore pressure. The subsequent flow-like deformation is caused by the strain-softening effect associated with large strains

The relaxation time model is introduced to analyse the thermo-mechanical problem for multi-layered media in this paper. The Fourier heat conduction equation is extended by introducing a relaxation time based on the Lord-Shulman model. For multi-layered media, the analytical layer-element method is employed to establish the global stiffness matrix equations by assembling the correlative layer-elements

Recent research has indicated the potential of optimizing the design of pile groups using system-based reliability. Binomial distribution can be used to optimize the design of redundant pile groups. The application of binomial system-reliability is challenged by the need for determining a framework for calculating a key input variable related to the maximum number of defective piles a pile group can

Sand production encountered in the 2013 offshore field gas production tests at the Nankai Trough, Japan, could be attributed to well failure during reservoir compaction. In this study, well integrity under various reservoir compaction patterns for the Nankai Trough case is examined using a well-formation finite element model. The modelling details include the inclusion of a cement sheath as well as

Optimization algorithms play an important role in the reliability analysis of slopes to determine the critical slip surface. In this study, the original hybrid algorithm based on black hole and differential evolution algorithms (BHDE) is modified to speed up the convergence rate. Subsequently, the modified BHDE (MBHDE) combined with the subset simulation (SS) is firstly applied to search for the critical

A manifold Lagrangian integration point method is proposed by combining the manifold coverage algorithm and a Lagrangian integral point finite element method, aiming to simulate the large deformation failure in slope engineering. The model is established based on the dual-discrete method with a fixed Eulerian background mesh and moving material particles. The method adopts the Eulerian mesh as the

This work presents a probabilistic analysis of three-dimensional (3D) seismic active earth pressures acting on rigid retaining walls that are designed to support cohesive-frictional soil masses. The analysis is implemented using sparse polynomial chaos expansions (SPCE) to represent the physical model responses. The deterministic evaluation of 3D seismic active earth pressures is conducted with the

The ultimate bearing capacity problem of rectangular surface footing over undrained clay with linearly increased strength is comprehensively analyzed with a numerical upper-bound method. For uniform soil, the present results are generally in accordance with available results and present the best upper-bound prediction when the three-dimensional effect is predominant. The obtained bearing capacity factor

Geologic disposal is a promising solution for a safe permanent isolation of accumulated high-level nuclear waste from nuclear powerplants. The behavior of host rock is highly coupled thermally, hydromechanically, and chemically. Numerical simulations of such coupled phenomena for the extremely long term (>100,000 years) and large length scale (>1 km) of geologic disposal remain to be computationally

The coupled simulations of dynamic interactions between the well, hydraulic fractures and reservoir have significant importance in some areas of petroleum reservoir engineering. Several approaches to the problem of coupling between the numerical models of these parts of the full system have been developed in the industry in past years. One of the possible approaches allowing formulation of the problem

In preloading ground improvement projects, vertical drains are frequently installed to accelerate the consolidation process of a soil stratum which is generally unsaturated and layered in natural. To address such issue, this study attempts to constitute a reliable two-dimensional (2D) plane strain consolidation system of layered unsaturated soil. A novel semi-analytical solution for this system is

The mechanical analysis of multiple tunnels at great depth is an extremely common problem in practical engineering. Previous studies usually used the Schwarz alternating method to solve the multiple-tunnel problem with an iterative scheme, which resulted in low efficiency and precision. To this end, this paper presents a non-iterative analytical method to calculate the mechanical field of multiple

Particle finite element method (PFEM) is an effective numerical tool for solving large-deformation problems in geomechanics. By incorporating the node integration technique with strain smoothing into the PFEM, we proposed the smoothed particle finite element method (SPFEM). This paper extends the SPFEM to three-dimensional cases and presents a SPFEM executed on graphics processing units (GPUs) to boost

The wetting behavior of aluminum (0 0 1) and silicon (001¯)basal surfaces of metakaolinite was investigated by means of force-field molecular dynamics simulations. The rationality of existing controversial metakaolinite models was verified and the Brindley and Nakahira model was confirmed. Kaolinite has mainly hydrogen bonding between the layers, which is sufficiently strong to prevent cleavage under

To investigate rock slope stability, a nonlinear strength-reduction numerical manifold method (NSRNMM) using a generalized Hoek-Brown (GHB) criterion is proposed. As it is difficult to implement the nonlinear strength reduction method (NSRM) with the use of the GHB criterion by directly reducing the GHB parameters, two equivalent Mohr-Coulomb (MC) criteria, namely, the instantaneous and average equivalent

In this paper, an original J2-deformation type model coupled with state-dependent dilatancy is further extended to a multiaxial stress space. Compared with most existing models, the proposed model only requires ten parameters, which can be easily calibrated, and does not involve any abstruse concepts in elastoplasticity theory. The model is then implemented into ABAQUS through a user-defined subroutine

Landslide tsunamis represent a highly complex fluid-solid interaction process and this complexity is one of the challenges in researching landslide disasters. Given the characteristics of landslide tsunamis, a coupled smoothed particle hydrodynamics (SPH)-discrete element method (DEM) code was developed and applied to simulate the process in this study. Based on the laboratory experiment that Fahad

The use of prefabricated vertical drains (PVDs) to improve soft soil has received much attention in the recent past, however, there is still a lack of rigorous analytical solutions that can incorporate the time- and depth-dependent behaviour of drains into the consolidation of multi-layered soil. This study thus presents a novel approach where the spectral method is used to capture the degradation

This paper investigates the stability of two circular tunnels at different depths in cohesive-frictional soils subjected to surcharge loading using a stable node-based smoothed finite element method (SNS-FEM). In the present method, the numerical integration domains are approximately circular regions of the node-based smoothing domain by the node-based smoothed finite element method (NS-FEM). Four

With the development of electronic detonators, the precise initiation timing has been controlled at the microsecond level, which are accurate enough to guarantee waveform collision at precise locations in hole. The accumulated energy effect by collision of two oppositely traveling in-hole detonation waves was proved theoretically based on impact dynamics theory. And the fragment size distributions

The stability of slurry trench is of importance in diaphragm wall construction. The local stability of slurry trench under seepage application is investigated in this research. In the current research, the local instability of slurry trench is identified as the soil collapse in an instable sublayer and a three-dimensional translational failure mechanism is developed. In this mechanism, the local stability

The discontinuum numerical modeling approaches widely used to simulate brittle rock failure employ the Voronoi tessellation technique to generate polygonal grain-like structures. Using this approach, called the grain-based model (GBM), the progressive micro-cracking leading to macroscopic fracturing and failure of brittle rocks can be realistically simulated. In this paper, a GBM is developed using

Free gas in sandy marine sediments is a common occurrence worldwide. A distinct feature of gassy sand is that, under undrained shearing, presence of occluded gas bubbles in the pore fluid can increase the undrained strength of sand at a relatively loose state, while reduce the strength of a relatively dense sand. Previous theoretical analyses have primarily focused on modelling the ‘beneficial’ effect

Granite residual soil is widely used as a subgrade material in pavement engineering. Previous studies have not investigated the influence of stress on the soil water retention curve for this type of unsaturated soil or its significance for predicting ground settlement. Thus, the aims of the present study were: (i) to experimentally investigate the water retention curves for granite residual soil at

In this paper, the effect of the adjacency of two strip footings on bearing capacity of rock masses was investigated using the upper bound analysis and finite element method. The modified Hoek-Brown nonlinear failure criterion was used for the rock mass. The effect of various parameters such as the distance between the two footings, Hoek-Brown parameters, surcharge pressure and unit weight of the rock

The undrained stability of dual circular tunnels buried in spatially random soils is investigated by imposing the random adaptive finite element limit analysis (RAFELA). The emphasis is on quantifying the effect of influential factors including the geometry parameters and spatially variability parameters on the bearing capacity and failure probability of tunnels by assuming a lognormal distribution

Current analytical solutions on the ground movements and stresses induced by shield tunneling in soft soils are generally based on the instantaneous excavation behavior. Furthermore, previous studies seldom took account of the influence of surcharge loading during tunnel excavation process. This paper introduces a complex variable analytical solution to estimate the deformation and stress of surrounding

The increasing urban population is leading to the exploitation of building sites close to sources of ground-borne vibration, such as railways and busy roads. Piled foundations can provide a significant vibration transmission path into a building, which can then cause disturbance to occupants and sensitive equipment. There is a strong need to develop numerical models that can capture the essential dynamics

The paper presents a numerical modeling study on the bearing capacity of two-tiered reinforced soil retaining walls. Numerical simulations are carried out using the finite element limit analysis (FELA) method, which is validated against results from model tests and other numerical simulation studies. Parametric analyses are carried out to examine the influences that footing location and width, upper

The responses of hydrate reservoir during gas production are complex due to the spatially and temporally evolving thermo-hydro-mechanical properties. Accurate modeling of the behavior, therefore, requires a coupled multiphysics simulator with a large number of parameters, leading to substantial computational demands. This makes it challenging to efficiently predict long-term reservoir responses. In

Piles used for jacket type foundation of offshore wind turbine are subjected to highly cyclic tension and compressive loading. The pile capacity under cyclic tension loading decreases with increased number of loading cycles due to reduction of the pile shaft resistance. A numerical simulation scheme is presented, which allows the calculation of the pile capacity degradation (CDM) due to cyclic loading

Stepped piles have been increasingly used as foundation elements for bridges and soft ground improvement in China. This paper derives an analytical solution of the torsional impedance of a stepped pile based on a wedged soil model. The accuracy of the developed solution is verified by degenerating the stepped pile into a straight pile. A parametric study is then conducted to investigate the influence

Due to the advantages of high bearing capacity and small settlement, rock-socketed bored piles have been commonly used as the foundation for most structures. In this paper, for the vertically loaded bored pile socketed into weak rocks, the shear failure process of the concrete-rock interface was divided into two stages, e.g., a dilatant sliding stage and a post-peak sliding stage, and a bilinear shear

This study presents an improved VOF-DEM model where the Darcian velocity and a compound variable are treated as unknowns in the pressure-velocity calculation procedure such that the use of interpolated porosity at cell faces is minimised and stability is ensured even if the porosity field is not smooth or even ragged. A higher-order porosity estimation method is also used such that the porosity and

Optimum fragmentation of rocks during blasting is pivotal for the productivity of mining and civil engineering systems. Extensive studies on the ubiquitous fragmentation phenomena in nature and artificial processes have attested to the dominant control of the effective dimensionality and material brittleness on the size distribution of fragments. In this study, by further demonstrating that the impact

This paper presents the impact of valley topography on the stability of an earth-rockfill dam slope during earthquakes. The valley site is simplified as an ideal trapezium. A series of three-dimensional numerical models with different valley floor widths and valley wall slopes are used to represent different geometries of the valley topography. A modified dimensionless valley topography coefficient

Flexible obstacles are used to reduce the impact load exerted by granular flows. However, grain-scale interactions between granular assemblies and flexible obstacles remain poorly understood, making it difficult to estimate the required resisting force. In this fundamental study, a flexible obstacle was simplified as a grain intruder and dragged through a static granular assembly. A new physical intruder