bluuebunny/crossref_metadata_2025_split huggingface dataset:
Load transfer from an elastic pile to a saturated porous elastic soil
Authors: Niumpradit Boonsrang , Karasudhi Pisidhi 
Published: August 2005

AbstractThe quasi‐static development of the force, pore pressure and displacement is obtained in the system of a circular elastic pile partially embedded in a saturated porous elastic soil, and loaded axially on the top. The porous elastic soil is governed by Biot's theory. The problem is decomposed into two systems, namely, an extended porous elastic half‐space in the absence of the pile characterized by the material constants of the medium, and a fictitious pile represented by a Young's modulus equal to the difference between the Young's moduli of the real pile and the medium. The problem is found to be governed by a Fredholm integral equation of the second kind. Laplace transforms are applied to time functions involved, and Hankel transforms to the radial coordinate of which the origin is at the centre of the pile. Numerical solutions are obtained for final and initial solutions for various practical values of the parameters involved.
Rock stresses due to local buckling of a surface layer (theory and applications)
Authors: Golecki J. J. 
Published: August 2005

AbstractThe theoretical aspects of mining in rock subject to tectonic stressing are still insufficiently clear. While rock mechanics uses Heim's rule and assumes the virgin stress to be generally lithostatic, earth science resorts to the folding theory and to different approaches in explaining geological phenomena.In this paper, a procedure is proposed for determining tectonic stresses in mining ground below a surface fold, the latter being assumed to originate through local buckling of the surface layer under tectonic action. For the purpose of this hypothesis, the concept of displacement along the interface of the layer and the surrounding incompetent rock is defined. In the case of elastic or viscous incompetent rock, the induced stress is obtainable by an integral equation approach.A numerical technique was developed accordingly for the zone of contact strain, and special attention is paid to interpretation of the singular integrals representing the boundary stress. Numerical results are presented as an illustration.
Heated mine room and pillar‐secondary creep response
Authors: Tillerson J. R. , Dawson P. R. 
Published: August 2005

AbstractHeated salt mine room and pillar simulations have been performed to provide information regarding parameters affecting room closure rates to designers of radioactive waste isolation facilities. A coupled secondary creep and heat transfer formulation with large strain capabilities was used to assess the effects of variations in creep law parameters, thermal properties, imposed boundary conditions, temporal integration and meshing resolution on room closure rates. Results indicate that the greatest effect results from variations in parameters appearing in the creep constitutive equation.
A comparison between finite element and finite difference explicit formulations for triangular and quadrilateral plane‐strain elements
Authors: Kunar R. R. , Minowa N. 
Published: August 2005

AbstractFor non‐linear dynamic problems, it has been recognized that an explicit time‐integration method of approach is a very efficient way of solving the dynamic equations of motion. The numerical formulation and computation for such problems fall into the two general categories of finite elements and finite differences. Over the years, there have been many arguments between schools which adopt the finite element approach and those which adopt the finite difference approach. At one extreme, arguments areconcerned with the superiority of each approach and at the other end of the spectrum the arguments are about which approach is a subset of the other. The most common of these arguments are concerned with efficiency and accuracy. This publication addresses the accuracy issue with specific reference to explicit calculations in which the analysis domain is discretized into triangular or quadrilateral plane‐strain elements. It concludes that if the same basic assumptions are made in the two approaches, they, will give identical answers for problems in this category.
Procedure, selection and application of plasticity models for a soil
Authors: Desai C. S. , Phan H. V. , Sture S. 
Published: August 2005

AbstractA five‐step procedure involving mathematical formulation, identification and determination of parameters and verification is presented for development and selection of appropriate and reliable constitutive law(s) for geologic media. Comprehensive analyses are performed toward determination of an appropriate law for a (artificial) soil. The most suitable model is obtained by critical evaluation of four different plasticity models; here verification and comparisons of predictions with observations from laboratory tests, and with those from two boundary value problems are used as the basis of the selection. The model thus selected is found to be appropriate for applications to relevant practical problems.
‘Infinite domain’ elements in finite element analysis of underground excavations
Authors: Beer G. 
Published: August 2005

AbstractThe Finite Element Method is frequently used to analyse problems involving an ‘infinite domain’. A typical problem is an underground excavation in prestressed infinite medium in either tunnelling or mining operations or a foundation in an infinite half space.This paper examines the implications of mesh truncation on the accuracy of the accuracy of the solution.At the same time, a more economical and accurate method of analysing these problems using special ‘infinite domain’ Finite Elements is presented.
On hardening anisotropy of K0‐consolidated clays
Authors: Pietruszczak St. , Mróz Z. 
Published: August 2005

AbstractThe combined isotropic‐kinematic hardening rule for clays is presented using the concept of a multisurface model discussed previously in Reference 1. The mechanical behaviour of clays after one‐dimensional consolidation is next simulated for the axisymmetric stress stress state. A general three‐dimensional formulation of constitutive relations is also presented.
A coupled finite element–rigid block method for transient analysis of rock caverns
Authors: Dowding C. H. , Belytschko T. B. , Yen H. J. 
Published: August 2005

AbstractA coupled finite element–rigid block model for the transient analysis of caverns in jointed media is presented. This coupling permits the modelling of lined openings in a jointed rock mass as well as the propagation of stress waves to the cavern. Both the finite element and the rigid block algorithms employ explicit time integration; an efficient, stable scheme is developed for coupling the two algorithms. Two numerical examples are given: one is a simple validation, the second is a representation of a lined cavern in a sparsely jointed medium.
The analysis of liquid storage tanks on deep elastic foundations
Authors: Booker J. R. , Small J. C. 
Published: August 2005

AbstractThe behaviour of a cylindrical liquid storage tank resting on a deep homogeneous elastic layer is examined. The analysis employs a substructure approach and proceeds by examining the behaviour of the tank base, the tank walls and the soil separately and developing flexibility matrices for each of these components. These flexibility matrices are then assembled and the complete soil structure system analysed.
Consolidation of axi‐symmetric bodies subjected to non axi‐symmetric loading
Authors: Carter J. P. , Booker J. R. 
Published: August 2005

AbstractIn many cases the analysis of the consolidation of axi‐symmetric bodies subjected to non axi‐symmetric loading may be carried out without recourse to a full three‐dimensional treatment. Advantage may be taken of the axi‐symmetric nature of the body and field quantities such as displacement and pore pressure can be given a Fourier representation. The problem is then reduced from one in three spatial dimensions (r, θ,z) and the time domain to one in two spatial dimensions (r,z) and the time domain.
Rheological behaviour effect of non‐newtonian fluids on steady and unsteady flow through a porous medium
Authors: Pascal H. 
Published: August 2005

AbstractThis paper describes the flow behaviour of certain non‐Newtonian fluids through a porous medium. A generalized Bingham rheological model of power‐law in the presence of a yield stress has been considered. Several problems of fluid mechanics, which appear currently in oil reservoir engineering, have been investigated and the rheological behaviour effect has been emphasized. The short time solutions have been formulated in terms of a moving boundary problem. The approximate solutions in a closed formwere obtained by means of the integral method. Several dimensionless groups have been found to be relevant in evaluating the rheological effect on the steady and unsteady and unsteady flow behaviour. The deviation from Newtonian flow behaviour has been illustrated using several numerical examples.
Elastic–plastic shear deformation of frictional granular materials
Authors: Szymanski M. B. 
Published: August 2005

AbstractA theory describing plastic deformation of granular (purely frictional) materials is presented. The theory is developed from postulates for energy dissipation and for the mode of plastic deformation. The postulates are based on some restrictions for the properties of granular materials and on a frictional analogy. A distinction is made between the description of plastic behaviour of a locally homogeneous and a locally non‐homogeneous material. An interpretation of the deformation process is presented which implies that the theory accounts for the changes in the density of some local non‐homogeneities underlying a plastic hardening effect. Based on this interpretation, an analogy between elastic–plastic behaviour of granular materials and frictional, sliding of two solid bodies is assumed. In the general case, the presented constitutive equations describe two hardening (softening) effects and are capable of describing both initial and advanced plastic deformations. A special, simplest form of the constitutive equations is examined in detail and a yield condition and a stress–strain relationship are derived. An example of elastic–plastic stress–strain–strength behaviour is presented for the cuboidal loading conditions.
Some applications of the boundary element method in geomechanics
Authors: Venturini W. S. , Brebbia C. A. 
Published: August 2005

AbstractThis paper presents the complete formulation for the application of the Boundary Element Method to solve non‐tension material problems. The formulation is based on including an extra term due to an initial stress field into the boundary integral statement. This is then used to iterate the solution until a state of non‐tension is achieved. The resulting iteration process is very simple to apply and basically consists only of a single matrix–vector product. The applications show that accurate resultscan be obtained for boundary discretizations involving a small number of unknowns. Whenever possible, results are compared with analytical solutions or finite elements.
The consolidation problem treated by a consistent (static) finite element approach
Authors: Cividini Annamaria , Rossi Adolfo Zavelani 
Published: August 2005

AbstractThe consolidation problem in a plane strain porous elastic medium is treated by adopting a consistent formulation of the finite element model. To this purpose, the fluid‐phase behaviour is modelled in static terms through a piecewise linear description of the pore pressure field and the behaviour of the two‐phase medium is consistently modelled through rigorously equilibrated piec̀ewise linear stress distribution.Incompressibility of the pore fluid and of the skeleton grains is assumed, as is linear elastic behaviour of the solid phase.After a compact description of the model, the governing equations for the continuum problem are recalled and the solution system for the discretized problem is obtained following Galerkin's method of weighted residuals. Some examples are finally illustrated, in order to assess the reliability of the approach and to introduce possible comparisons with other methods.
A finite element model for the analysis of tailored pulse stimulation of boreholes
Authors: Swenson D. V. , Taylor L. M. 
Published: August 2005

AbstractA constitutive model is described for the prediction of dynamic crack formation in geological media. The model includes a simple tensile failure criterion for crack formation and a soil plasticity model for both deviatoric and volumetric plasticity. Numerical results are presented which show that the model reproduces the observed dependence of fracture formation on loding rate for dynamic pressure loading of boreholes. The use of the model as a numerical tool for design is demonstrated through two example parameter studies.
On the solution of plane flow of granular media for jump non‐homogeneity
Authors: Michalowski Radoslaw L. 
Published: August 2005

AbstractThis paper deals with the plane plastic equilibrium of a cohesive frictional material in the case of a jump non‐homogeneity. Three types of interface separating rigid‐plastic bodies with different material parameters are distinguished: (i) a perfect adhesion contact, (ii) a thin layer of a material different from the adjacent bodies, (iii) a combined frictional‐adhesive contact. A sliding along the interface may occur if certain conditions are satisfied. For the first two types of joint, the direction and propagation of the velocity jump vector along the interface follow from the classical theory of plane plastic flow. In the third case, the potential sliding rule relating the velocity jump vector to the limit condition of the joint, or to the potential different from the limit condition, may be adopted. The direction of the velocity jump vector results from such a rule.The problem of stability of a slope, being continuously non‐homogeneous in one region, and homogeneous in another, is shown in an example. The two regions of the slope are separated by the interface, a thin layer of a different material, (type ii). The associated flow law for both regions of the slope and for the material of the interface is assumed.
On the theory of consolidation with double porosity—III A finite element formulation
Authors: Khaled M. Y. , Beskos D. E. , Aifantis E. C. 
Published: August 2005

AbstractWe employ a finite element method to consider the numerical solution of Aifantis' equations of double porosity.1–5 The physical and mathematical foundations of the theory of double porosity were considered in two previous papers, 6,7 where analytical solutions of the relevant equations are also given. For practical purposes and for the completeness of the presentation, we re‐derive the basic equations without resorting to the more rigorous scheme of multiporosity theory.1–6 Instead, we follow the more familiar approach of Biot8,9 which we now extend from the case of single porosity to the case of double porosity. Then a general finite element formulation of the relevant eqations is thoroughly discussed and explicitly described for the two‐dimensional case where four‐node rectangular non‐conforming isoparametric elements are employed. Three numerical examples are presented in detail to illustrate the method and assess the differences between single and double porosity models in consolidation.
Rapid expansion of a cylindrical cavity in a rate‐type soil
Authors: Davis R. O. , Scott R. F. , Mullenger G. 
Published: August 2005

AbstractAn analytical solution for rapid (undrained) expansion of a long cylindrical cavity from initially zero radius is presented. A simple rate‐type soil model possessing the salient features of the modified Cambridge critical state model is used. Application of the solution to determination of the stress field surrounding a pile immediately after driving is discussed.
Induced anisotropy during plastic straining
Authors: Baker R. , Desai C. S. 
Published: August 2005

AbstractThe restrictions imposed by the form‐invariance principle on the structure of the elasto‐plastic constitutive law for small strains are examined. It is shown that the yield and plastic potential functions may depend on the joint invariants of the stress and plastic strain tensors in addition to their dependence on the direct invariants of these tensors and additional scalar hardening parameters such as the plastic work; inclusion of the joint invariants as parameters in the constitutive functions allows for induced anisotropy during plastic deformation. It is demonstrated that the physical meaning of the joint invariants is related to the deviation of the principal directions of the stress tensor from those of the plastic strain tensor. It is also shown that only three cases of anisotropy (orthorhombic, transverse and isotropy) are possible in the types of material models discussed herein. The model proposed in this paper does not imply coaxiality between the principal directions of the stress and, plastic strain increment tensors; however, implications of the assumption of coaxiality on the structure of the constitutive equations is investigated. It is shown that coaxiality does not necessarily imply isotropy, but no deviations from coaxiality can be expected in isotropic materials.
A stochastic model of soil erosion
Authors: Mossaad Mostafa E. , Wu Tien H. 
Published: August 2005

AbstractThe erosion model computes the rill and inter‐rill flow over a surface with random roughness, and the erosion caused by this flow. The measured roughness of a surface is analysed and used to generate random surfaces for the simulation process. Computations are carried out over a number of time intervals; the steady state condition is assumed for each interval. Changes in the surface geometry due to erosion during an interval are used to revise the surface for the subsequent interval. The model includes simplified mechanisms to simulate ponding, deposition and failure of side slopes of rills.
A finite element formulation for brine transport in rock salt
Authors: Ratigan J. L. 
Published: August 2005

AbstractA set of coupled field equations is developed for transport of liquid brine in natural rock salt. The natural rock salt consists of individual crystals brought together so that only a portion of the crystal faces or grain boundaries contribute to the hydraulically connected pore space. Transport of brine inclusions within individual crystals is considered to be thermally driven; whereas transport along crystal interfaces or grain boundaries is considered to be pressure driven. The field equations for both transport mechanisms are developed and incorporated in a finite element program. An analytical solution to a one‐dimensional boundary value problem is derived and compared to the finite element solution. An application of the finite element code to radioactive waste emplacement is briefly discussed.
Slippage and re‐initiation of (hydraulic) fractures at frictional interfaces
Authors: Lam K. Y. , Cleary M. P. 
Published: August 2005

AbstractThe analysis of mechanisms which could control the growth of fractures in non‐homogeneous regions is of paramount importance. One such mechanism is the behavior of the fracture as it reaches a frictional interface; coupled with this is the question of re‐initiation, e.g. whether a fracture can be contained within the region of initiation. Though the problems of slippage have been dealt with by other investigators, the present paper gives a more comprehensive picture and detailed treatment: effects of various frictional models at an interface are considered for a crack which intersects it at any angle; specialization then allows comparison with existing results in the literature.The problem of re‐initiation, after slippage has occurred at a frictional interface, is also considered, using two different models. First, by introducing microcracks in the adjacent stratum and looking at the effects on propagation criteria and, secondly, by examining the actual distribution of the stress tangential to the slip surface; detailed computations are performed and a simple criterion for re‐initiation is given, relating the re‐initiation stress dominantly to the confining stress on the interface.
Dynamic response analysis of embankment dams
Authors: Chugh Ashok K. 
Published: August 2005

AbstractA one‐dimensional wave propagation method for earthquake response analysis of horizontally‐layered sites of infinite lateral extent is adapted to account for the finite cross‐sectional dimensions of an embankment dam overlying a foundation deposit which may be considered infinite in its lateral extent. The procedure is used to study the response of an existing embankment dam for an actual earthquake record. A two‐dimensional dynamic finite element analysis is also performed for this case. The records of ground acceleration at an outcropping base rock and at the crest of the dam are available for the site. The comparisons of computed and observed responses support the modified use of the simple numerical procedure.
Special finite elements for analysis of soil consolidation
Authors: Sandhu Ranbir S. , Lee Shyan Chyun , The Hwie‐Ing 
Published: August 2005

AbstractUse of “singularity” elements to model pore pressures in the vicinity of free‐draining loaded surfaces, immediately after application of loads at these surfaces is discussed. One‐dimensional consolidation is considered. Comparison of numerical results with the exact solution shows that use of specially designed elements approaching “singularity” may succeed in reducing the error in pore pressures.
Singularity elements for seepage analysis
Authors: Aalto J. 
Published: August 2005

AbstractA technique for locating the nodal points of standard isoparametric quadrilateral elements properly around a discharge velocity singularity point in a soil seepage flow problem is presented. It is based on the analytical solution of the problem in an infinite medium and gives simple formulae for calculating the nodal coordinates. The effectiveness of the method is justified with examples.
Three dimensional analysis of slope stability
Authors: Leshchinsky D. , Baker R. , Silver M. L. 
Published: August 2005

AbstractA 3‐D mathematical approach to slope stability, which is based on limiting equilibrium and variational analysis, is presented. In the initial formulation there are three unknown functions: the slip surface, the normal stress and the shear stress direction over this surface. The minimum factor of safety is sought through variational extremization. The analysis indicates that the factor of safety is independent of the normal stress distribution over the critical slip surface. It also indicates that the direction of the elementary shear force over the slip surface depends on the slip surface function, but not on the normal stress function. The analysis yields a non‐linear first order partial differential equation, relating the slip surface and its first partial derivatives. By limiting the analysis to symmetrical problems an ordinary differential equation, governing the slip surface path on the plane of symmetry, is derived. This equation enables the development of a numerical procedure to determine the minimal factor of safety of symmetrical 3‐D slopes. Two possible failure modes are determined for homogeneous slopes. One mode consists of finite 3‐D sliding body and the second represents cylindrical failure. Numerical analyses for some simple cases, of homogencous slopes are presented.