bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inexpensive but technically sound mine pillar design analysis
Authors: Pariseau William G. 
Published: August 2005

AbstractA simple algorithm (PILLR) for obtaining by two‐dimensional analysis thee essential results that would be obtained in an actual three‐dimensional finite element analysis of stress about mine pillars in flat‐laying stratified rock is presented. A series of comparisons between the distributions of the local factor of safety calculated from the results of three‐dimensional analysis and that obtained in the PILLR two‐dimensional analyses for pillars of length/width ratio ranging from 0.33 to 8.0 shows the algorithm to be quite effective. The average vertical stress over the horizontal mid‐plane of the pillar in the PILLR two‐dimensional analyses is always within 0.5 per cent of the exact average; the local safety factor distribution is always within 10 per cent of the three‐dimensional result. The ratio of the computer core x time product for the 2D' to 3D analyses is approimately 1/150. Additional improvements ard possible, although with the current PILLR algorithm 3D analyses require less than 1 minute for execution. This fact makes technically sound 3D mine pillar design analyses economically feasible on a routine basis.
Vibrational characteristics of soil deposits with variable wave velocity
Authors: Gazetas George 
Published: August 2005

AbstractThe paper studies certain dynamic characteristics of soil deposits with wave velocities increasing with depth according to (1 + μz)m, where m = 1, 2/3, 1/2, 1/4 and 0. Analytical solutions are presented for the fundamental periods, mode shapes and amplification functions due to vertically propagating shear waves and the effects of type (m) and rate (μ) of heterogeneity are systematically investigated. The analytical–numerical techniques are used to study the attenuation with depth in a deposit of the vertical and horizontal displacements due to travelling of Rayleigh waves. Differences attributed to different heterogeneities are discussed in connection with the machine isolation problem and the steady‐state vibration technique for soil exploration. Finally, the dependence on soil heterogeneity of the time–distance response curves, obtained during seismic refraction surveys, is graphically illustrated.
On the non‐linear ‘squeezing’ effects around circular tunnels
Authors: Gioda Giancarlo 
Published: August 2005

AbstractAn analysis is presented of the non‐linear creep effects around a deep circular tunnel driven in ‘squeezing’ ground. The time‐dependent behaviour of the geotechnical medium is described by means of a simple viscoplastic rheological model capable of approximating primary, secondary and tertiary creep behaviours. It is shown that tertiary creep can be allowed for by providing a suitable law governing the variation of some material parameters (such as viscosity) with stresses and strains. The basic operations of the ‘evolutive’ procedure adopted for time integration are outlined. Along each time integration step, quadratic variations of the stress and strain fields and linear variations of the material parameters are assumed. The results of various finite element analyses are presented concerning both lined and unlined cases. For the lined cases, the influence of the liner stiffness and of the time elapsed between the end of excavation and the liner installation is considered.
Incremental constitutive law for sands and clays: Simulations of monotonic and cyclic tests
Authors: Darve F. , Labanieh S. 
Published: August 2005

AbstractAn incremental formulation of constitutive laws is first presented and the fundamental notion of incremental non‐linearity, necessary for the description of cyclic behaviour of soils, is emphasized.The incremental constitutive law for soils and its principal assumptions, which make it more general than the classical elastic–plastic models are detailed.The constitutive parameters of Hostun sand and Grundite clay are then given, as well as a comparison of theoretical results with experimental axisymmetrical and true triaxial measurements (Hostun sand tests at Grenoble and Grundite clay tests at Berkeley). Different cyclic behaviour simulations are presented, as well as an example of cyclic liquefaction of Monterey loose sand. Finally, a simple shear test is simulated.
Two practical examples of numerical approaches for solving discontinuity problems in dam design
Authors: Lima V. Souza , Abrahão R. A. 
Published: August 2005

AbstractThis paper draws attention to the great influence certain types of discontinuities in foundation rock masses can have on dam design. By means of two practical examples, the role of numerical procedures in the solution of stability and deformation problems posed by foundation heterogeneities is discussed and emphasized. Some basic theoretical considerations regarding the limit‐states and the concept of safety to be used in dam design are also presented as a complement to the analyses description.The case of the Ãgua Vermelha dam, recently built in southern Brazil, is the subject of the first example. Here, a major joint in the basaltic foundation was the decisive geological feature for the stability analyses which were performed by means of the finite element method. The second example refers to the Itaipu dam, a record‐breaking Brazilian–Paraguayan hydroelectric development. Marked sub‐horizontal discontinuities between lava flows, greatly reducing the strength and stiffness of the basaltic rock masses, were of main concern in this case. The results of the foundation studies, with due help of numerical procedures, called for the construction of concrete shear keys, in order to achieve a satisfactory margin of structural safety.
Modelling microcrack kinetics in rocks
Authors: Stout R. B. , Thigpen L. 
Published: August 2005

AbstractMathematical concepts of statistical mechanics are use here to formulate the problem of microcrack kinetics. A stochastic distribution function is defined to characterize some modelling parameters of microcracks. This formalism results in an integral–differential equation of the Boltzmann type. A functional form for the microcrack production rate is imposed to model dilatancy and failure under shear‐loading histories. This simple model illustrates some concepts of this theoretical approach.
Two‐dimensional stresses in a saturated poro‐elastic foundation beneath a rigid structure—part. I. An impervious dam in a river
Authors: Mei Chiang C. , Mynett Arthur E. 
Published: August 2005

AbstractThe problem of an impervious dam on a poro‐elastic foundation is solved analytically. Using the known solution for the fluid pressure in the pores, the elastostatic stress field in the solid skeleton is analysed by reduction to two simpler problems whose solutions can be obtained by complex variable techniques. For welded contact, the rotation of the dam base is then found along with the stresses and strains in the ground. Modification for finite friction along the base is outlined in the appendix.
A numerical solution for the stability of a vertical cut in a purely cohesive medium
Authors: Cascini Leonardo 
Published: August 2005

AbstractThe problem of the critical height of a vertical cut in a purely cohesive medium has been repeatedly dealt with by several authors and, in spite of its apparent simplicity, the characterization of satisfactory solutions has presented, for a considerable period, notable difficulties. The present paper supplies the results obtained with a numerical method, which has so far been applied successfully to a considerable number of problems.
Application of a Cam–Clay model to overconsolidated clay
Authors: Amerasinghe S. F. , Kraft L. M. 
Published: August 2005

AbstractThe yield locus governing the stress–strain response of a soil may degrade during rebound at high overconsolidation ratios. The cause can be attributed to a breakdown in bonding. A Cam–Clay model is applied to account for the degrading yield locus, and the influence of this degradation is assessed using a theoretical approach for friction pile capacity. Stress changes in the soil continuum due to pile installation and setup are simulated by cylindrical cavity expansion and radial consolidation, anda segment loading model is used to determine the effective stress change in the soil at peak load transfer under undrained conditions. The results indicate that plastic rebound affects peak load transfer to at least the same extent as shear strength.
Fundamental results concerning the settlement of a rigid foundation on an elastic medium due to an adjacent surface load
Authors: Selvadurai A. P. S. 
Published: August 2005

AbstractThis paper examines the interaction between a rigid circular foundation resting in smooth contact with an isotropic elastic halfspace and a concentrated surface load which acts at a finite distance from the foundation. Owing to the action of the external load the rigid foundation experiences an extra settlement and a tilt. The expressions for the extra settlement and the tilt are evaluated in exact closed form. It is also shown that these deformations due to the external load satisfy Betti's reciprocal theorem. The auxiliary solution required for the application of the reciprocal theorem is derived from the analysis of the problem of a rigid circular foundation resting in smooth contact with an elastic medium and subjected to an eccentric load. The, results developed for the interaction between the rigid circular foundation and the external concentrated load are utilized to generate, among others, solutions for the settlement and tilt induced at a rigid foundation due to its interaction with uniformly or non‐uniformly distributed loads with circular and square plan shapes.
Three‐dimensional analysis of Infiernillo dam during construction and filling of the reservoir
Authors: Justo J. L. , Saura J. 
Published: August 2005

AbstractA three‐dimensional finite element program has been prepared to study the behaviour of Infiernillo dam during construction and filling of the reservoir. A linear stress‐strain behaviour of materials has been assumed. The parameters are deduced from the movements measured during construction, checked with the results of oedometer tests at the laboratory. The no tension strength of granular materials has been introduced following Zienkiewicz et al.9 Collapse of the upstream shell is introduced into the calculation in a simple way from the settlement observed upon flooding under constant stress at the oedometer.A good agreement is found between measured and calculated movements.
A note on indirect boundary element methods for the diffusion equation
Authors: Sharp S. 
Published: August 2005

AbstractThis paper corrects an impression, created by a recent contribution to the International Journal for Numerical and Analytical Methods in Geomechanics, that the mathematical equivalence of the direct and indirect boundary element methods for the diffusion equation implies that their respective computational needs with regard to the body integral terms are equal. It is shown that in a stepwise implementation of the numerical procedure for solving a finite body problem, indirect methods requirean integration over an infinite region and not merely over the body as is the case for the direct version.
A constitutive model for sand with anisotropic hardening rule
Authors: Mróz Z. , Pietruszczak St. 
Published: August 2005

AbstractAn anisotropic hardening model for sand or other granular materials is presented. The state of initial densification is represented by a configuration surface and the state of loading by a loading surface in the stress space. The domain of elastic response may not exist and the irreversible strain is assumed to occur for both active and reverse loading. The derived constitutive equations are applicable both for dense and loose sands. Some model predictions are compared with available experimental data for triaxial compression and extension under undrained condition.
A family of Houbolt methods for dynamic vibration problems
Authors: Thomas R. M. , Addison C. A. , Gladwell I. 
Published: August 2005

AbstractWe extend the well‐known Houblt method for dynamic vibration problems to a class of methods suitable for a variable‐order variable‐step computer program implementation. We discuss the numerical stability properties of these methods and derive a family of extensions with improved stability properties. Finally we present some numerical results which compare a variety of Houbolt methods with other well‐known Backward Differentiation methods, demonstrating in passing the practical value of the stability, concepts.
A simple contact–friction interface element with applications to buried culverts
Authors: Katona Michael G. 
Published: August 2005

AbstractA simple friction–contact interface element is introduced which simulates frictional slippage, separation, and re‐bonding of two bodies initially mating at a common interface and subsequently deforming with an arbitrary static loading schedule. Constraint equations between initially mating node pairs and the general principle of virtual work are used to formulate the interface element for a finite element solution procedure. Some advantages of the interface element include; easy implementation intostandard finite element programs, direct determination of interface forces without round‐off problems, and the generality afforded by the virtual work formulation to include other non‐conservative models in the system.The application of the interface element to an idealized buried culvert problem illustrates that the model behaves properly. A second application, for a long‐span culvert installation with incremental soil loading, demonstrates the importance of modelling slippage at the culvert–soil interface in order to conform with experimental observations.
Multi‐laminate model of clays—a numerical evaluation of the influence of rotation of the principal stress axes
Authors: Pande G. N. , Sharma K. G. 
Published: August 2005

AbstractA new framework for the development of constitutive models based on certain aspects of physical theories of plasticity is proposed. The resulting Multi‐laminate model of clays has the same response as the Critical state model provided no rotation of principal stress axes takes place during plastic flow.The influence of rotation of the principal stress axes on the volumetric and deviatoric plastic strains has been numerically evaluated. In undrained saturated, normally consolidated clays considerable excess pore pressure may build up due to rotation of the principal axes only. Numerical studies of the collapse of footings indicate that significant rotations do not take place in this class of problems and consequently the collapse load is only marginally reduced.
A material model for inelastic rock deformation with spatial variation of pore pressure
Authors: Smith M. B. , Pattillo P. D. 
Published: August 2005

AbstractThis paper sets forth the theoretical background and basic numerical expressions for the incorporation of elastic‐plastic constitutive equations for ductile rock into a finite element computer code. The derivation of an expression for the total strain rate is performed both for a total stress formulation and for a formulation that employs the concept of effective stress for inelastic behaviour. Specific expressions for the incremental strain rate are presented for the case of a porous material having a quadratic initial yield surface and observing the associated flow rule with a special hardening law for subsequent plastic deformation. A final section of the paper summarizes the expressions required to insert the quadratic yield surface model into a finite element code.
Dynamic behaviour of saturated porous media; The generalized Biot formulation and its numerical solution
Authors: Zienkiewicz O. C. , Shiomi T. 
Published: August 2005

AbstractThe basic equations of motion for porous media were established by Biot and despite many subsequent rederivations, are, with minor modifications, relevant today. However, some changes of variables and approximations are on occasion useful, and this paper discusses the alternative forms available and their relative efficiency of solution in the numerical context. Here penaity methods prove once again useful. The paper is illustrated with examples covering phenomena of different periods ranging froms hock excitation to slow consolidation which are treated in a single unified program.
Localization of deformations in elastic‐plastic solids
Authors: Prevost Jean H. 
Published: August 2005

AbstractLocalization of deformation in elastic‐plastic solids subject to plane strain deformation are investigated numerically. It is shown that the localization may be captured accurately in finite element models by employing (1) the elastic‐plastic material stiffness to form the global stiffness, (2) in the case of symmetrical configurations, an imperfection in the form of a weak element, and (3) in the case of incompressible materials, a reduced selective integration scheme which alleviates mesh ‘locking’. Accuracy of the technique is demonstrated by applying it to analyse the classical punch and slope stability problems. Its versatility is illustrated by applying it to analyse finite deformation problems and shear bands formations in associative and non‐associative elastic‐plastic solids.
Trapezoidal footings on non‐linear subgrades
Authors: Chandra S. , Madhav M. R. , Iyengar N. G. R. 
Published: August 2005

AbstractThe pressure versus settlement response is highly non‐linear for soils, in general. In the present study, a cubic equation of the type p = K1w − K2w3 is suggested to incorporate the non‐linear behaviour. A trapezoidal footing with constant depth resting on a subgrade having non‐linear response is analysed. The resulting fourth order non‐linear differential equation with variable coefficients is solved by using the Galerkin technique and beam characteristic functions are employed to obtain faster convergence. The results are presented in the form of non‐dimensional charts for valid ranges of footings and soil parameters.
Comparison of finite and infinitesimal strain consolidation by numerical experiments
Authors: Meijer Karel L. 
Published: August 2005

AbstractA number of computations have been performed in order to gain an insight into whether or not the non‐linear finite deformation theory must be applied in consolidation problems. These numerical experiments were preluded by tests to determine the correct model size and the fineness of the discretization. For this an analytical solution served as a gauge. The conclusion is that with stiffnesses of the order of ten times the external load, moderate deviations appear in both the effective stresses and the pore pressures.
Consolidation around a point heat source
Authors: Booker J. R. , Savvidou C. 
Published: August 2005

AbstractWhen a heat source such as a canister of radioactive waste is buried in a saturated soil the temperature changes that occur will cause the pore water to expand a greater amount than the voids of the soil. The temperature change will thus usually be accompanied by an increase in pore pressure. If the soil is sufficiently permeable these pore pressures will dissipate. This paper develops an analytic solution for the fundamental problem of a point heat source buried deep in a saturated soil.
The effect of pore‐fluid compressibility on failure loads in elasto‐plastic soil
Authors: Griffiths D. V. 
Published: August 2005

AbstractThe influence of pore‐fluid compressibility on failure loads in certain soil mechanics problems is investigated. The results are tested using a finite element approach treating the soil as an elasto‐plastic material. A limiting value for the pore‐fluid compressibility to give satisfactory solutions and numerical stability is suggested.
Effect of stone column yield on settlement of rigid foundations in stabilized clay
Authors: Balaam N. P. , Booker J. R. 
Published: August 2005

AbstractIn this paper the settlement of a rigid foundation supported by a layer of clay which has been stabilized with stone columns is considered. The results of an analytic solution for the settlement, assuming no yield occurs in the clay or columns, have been presented in a previous publication. This solution is now used to develop an interaction analysis which takes account of yielding within the stone columns.This interaction analysis is based on a number of plausible assumptions regarding the behaviour of the clay and columns. In order to check the validity of these assumptions elasto‐plastic finite element analyses have been performed and the agreement between the two methods is very good. However, the computational effort required for the finite element analyses is many orders of magnitude greater than that for the interaction analysis.This analysis has been used to generate a number of parametric solutions which provide a basis for estimating the reduction in settlement of the foundation due to the stabilization of the clay.
Condensation of elastic half space soil stiffness matrix considering symmetry
Authors: Sharma K. G. 
Published: August 2005

AbstractThe finite element formulation for deriving the soil stiffness matrix by idealizing the foundation as an elastic half space is presented. The procedure for condensation of the soil stiffness matrix taking symmetry into consideration is discussed. Computation time is considerable reduced when a condensed soil stiffness matrix is used for the finite element analysis of rafts resting on an elastic half space.
Torsional stiffness of non‐uniform and hollow rigid piers embedded in isotropic elastic media
Authors: Rajapakse R. K. N. D. , Selvadurai A. P. S. 
Published: August 2005

AbstractThis paper examines the torsional response of a rigid pier type foundation, with a non‐uniform or hollow cross‐section which is embedded in bonded contact with a layered elastic half space. The tractions which act at the axisymmetric boundary surface between the pier and the surrounding elastic medium are represented by discretized regions of uniform traction. The compatibility of deformation at the boundary is used to determine the interface stress distribution. The torque‐rotation response for the, rigid pier foundation is obtained for different choices of the pier geometry and shear modulus mistnatch between the layer and the underlying half space.
Two dimensional discontinuous deformation analysis
Authors: Shi Gen‐Hua , Goodman Richard E. 
Published: August 2005

AbstractThis paper explains a novel ‘back‐analysis’ shceme to determine rock mass behaviour modes from an array of deformational measurements. The input will be the locations of data points and the set of measured displacements, as well as description of the locations and orientations of planes of discontinuity, and the blocks they determine. The output, drawn by the computer, will be the set of block displacements, rotations, and strains that determine the behavioural mode of the mass.
Analysis of vertically loaded pile groups
Authors: Chow Y. K. 
Published: August 2005

AbstractAn approach is presented for the analysis of linear and non‐linear responses of vertically loaded pile groups. The soil behaviour of individual piles in modelled using load‐transfer curves and the pile‐soil‐pile interaction is determined based on Mindlin's solution. Good agreement between the present method of analysis and the rigorous boundary integral method is observed for the computation of the response of pile groups embedded in a homogeneous, isotropic elastic half‐space. The computed non‐linear response of pile groups compares favourably with measured results from field load tests.