bluuebunny/crossref_metadata_2025_split huggingface dataset:
The reliability of earth slopes
Authors: Tobutt D. C. , Richards E. A. 
Published: August 2005

AbstractMethods recommended for calculating the probability of failure of earth slopes, as distinct from factor of safety, are discussed. In particular the ‘Level II’ and ‘Level II’ approaches as defined by the Joint Committee of Structural Safety (J.C.S.S.) are referred to; these are set forth in C.I.R.I.A. Report No. 631 and attention is drawn to the contributions therein by M. J. Baker and M. Horne, and to how these considerations affect this particular problem. The mechanical model used throughout is Bishop's simplified method2.
Optimal lower bound of passive earth pressure using finite elements and non‐linear programming
Authors: Basudhar P. K. , Valsangkar A. J. , Madhav M. R. 
Published: August 2005

AbstractThe present study pertains to the finding of the lower bound solution, formulating it as a non‐linear programming problem using the generalized method developed by Lysmer with certain variations to incorporate the non‐linear no‐yield condition constraints directly in the analysis. The method considers the family of plane stress fields having the property that all stresses vary linearly within each triangular element of some mesh which covers the soil mass under study. For this type of stress field it is possible to express all equilibrium conditions as a set of linear constraints and the no‐yield as a set of non‐linear constraints. The boundary condition constraints may be of linear equality or inequality type. By expressing some of the design variables in terms of the remaining variables the linear equality constraints are implicity satisfied. Such a technique minimizes the complexity of the problem by eliminating the equality constraints and reduces the dimensionality of the problem, saving much, computational effort. The optimal lower bound is isolated by formulating it as a non‐linear programming (NLP) problem subjected to both linear and non‐linear inequality constraints. The sequential unconstrained minimization technique using the extended penalty function method as suggested by Kavlie has been used to isolate the optimal lower bound. The method has successfully been applied to the passive earth pressure and bearing capacity problem.Numerical results are obtained and compared with Lysmer's solution to show the effectiveness of the present approach.
The eccentric loading of a rigid circular foundation embedded in an isotropic elastic medium
Authors: Selvadurai A. P. S. 
Published: August 2005

AbstractThis paper examines the problem of the eccentric loading of a rigid circular disc‐shaped foundation embedded in bonded contact with an istropic elastic medium of infinite extent. The solution of this problem is achieved by using a Hankel integral transform technique which reduces the problem to two sets of dual integral equations. These systems of dual integral equations represent the equations which govern the axisymmetric and asymmetric states of deformation induced by the loaded foundation. Explicit results are derived both for the displacement and rotation of the circular foundation and for the contact stress at the interface.
Flow nets from finite element data
Authors: Christian John T. 
Published: August 2005

AbstractFinite element solutions for steady‐state flow of fluids through porous media do not include an explicit develpoment of the flow net, and many engineers find this lack frustrating. To solve for the stream function, the analyst can use essentially the same finite element routines as he used for the potential, but the matrix corresponding to the hydraulic conductivity isnotthe inverse of the conductivity. Contouring the potential and the stream function is done element by element; certain anomalous situations are described in an appendix.
Finite element modelling of ground surface displacements due to underground blasting
Authors: Blair D. P. 
Published: August 2005

AbstractElastic wave radiation from an equivalent cylindrical cavity due to an underground explosion is considered in detail. Both static and steady state dynamic finite element models are used to investigate the surface displacements due to the interaction of such wave radiation with both the free surface topography and stope formation. For a blast 430 m below the surface the models predict a negligible displacement effect due to the irregular topography but a significant effect due to the stope. A comparison between the models and a site experiment verified the cylindrical wave nature of the problem. Due to experimental uncertainties however it was difficult to clearly detect the surface displacement effect due to the large underground open stope.
Consolidation with threshold gradients
Authors: Pascal Florica , Pascal Henry , Murray D. W. 
Published: August 2005

AbstractEvidence for threshold gradients is reviewed. The consolidation problem, with threshold gradient, is properly formulated and solved numerically. An approximate analytical solution is also developed. The influence of a threshold gradient on the time rate of settlement is examined, and it is shown that by modifying the definition of the degree of consolidation a good approximation to the threshold gradient problem can be obtained directly from the Terzaghi solution. It is also shown that threshold gradients will have no influence on odometer testing and their effect is, therefore, to reduce the primary compression below that predicted from standard tests.
Multiplicity of numerical solutions for slope stability problems
Authors: Chugh Ashok K. 
Published: August 2005

AbstractExistence of more than one numerical solution to the slope stability equations derived on the basis of force and moment equilibrium requirements of statistics is indicated. These solutions satisfy the boundary conditions at both ends of a potential slide mass. In the particular case considered, the details of the calculated response for the slices for each solution set assist the designer in selecting the more reasonable solution to the problem.
Analysis of rigid rafts supported by granular piles
Authors: Balaam N. P. , Booker J. R. 
Published: August 2005

AbstractSolutions for the magnitude and rate of settlement of rigid foundations supported by soil reinforced with granular piles are presented. An analytic solution using the theory of elasticity is developed for the settlement of the foundation and expressions for evaluating the moment and shear distributions across the foundation are given. A solution for the increase of the rate of settlement due to the presence of the granular piles has been found by a numerical solution of Biot's equations of consolidation.
Pore water pressure in natural slopes
Authors: Chugh Ashok K. 
Published: August 2005

AbstractEstimating subsurface pore water pressures in natural slopes along the periphery of rivers and reservoirs for future conditions, created by the operational requiremets to meet increases in energy demand from the observed data of the past and present, operations, is possible with the use of a mathematical model. An effective algorithm for calculating pore water pressure at any location in a slope stability section is to use a complete polynomial and to assure geometric invariance of the calculated results.
Consolidation analysis for partly saturated clay by using an elastic–plastic effective stress–strain model
Authors: Chang C. S. , Duncan J. M. 
Published: August 2005

AbstractThe theory of consolidation is extended to partly saturated clay soils, and formulated for finite element analyses. This formulation couples the effects of both stress and flow. It takes account of variations of this permeability of the soil and compressibility of the pore fluid with changes in void ratio, and the non‐linear stress–strain behaviour of soil. The Cam Clay model is revised to model the stress–strain behaviour of compacted soils. The compressibility of pore fluid is derived using Boyle's Law and Henry's Law, taking into account the effect of surface tension. An empirical equation is developed for permeability of pore fluid. An example of settlement of a footing on partly saturated soil is described and discussed.
Finite element methods for geothermal reservoir simulation
Authors: Zyvoloski George 
Published: August 2005

AbstractTwo finite element algorithms suitable for long term simulation of geothermal reservoirs are presented. Both methods use a diagonal mass matrix and a Newton iteration scheme. The first scheme solves the 2N unsymmetric algebraic equations resulting from the finite element discretization of the equations governing the flow of heat and mass in porous media by using a banded equation solver. The second method, suitable for problems in which the transmissibility terms are small compared to the accumulation terms, reduces the set of N equations for the Newton corrections to a symmetric system. Comparison with finite difference schemes indicates that the proposed algorithms are competitive with existing methods.
Effects of fluid resistance in the mine waste dam‐break problem
Authors: Jeyapalan Jey K. 
Published: August 2005

AbstractA characteristic common to most mine tailings dam failures is that the mine tailings tend to liquefy and flow over substantial distances, with the potential for extensive damage to property and life. In order to be able to assess the potential for damage in case of such a failure, it is necessary to be able to predict the characteristics of the flow and the possible extent of flood movement. A procedure that has some potential for such flow analyses is described in this paper. When fluid resistanceis neglected, the solution of the simple dam‐break problem is readily found using the shallow water theory. However, near the head of the mine waste dam‐break flood wave the laminar resistance resistance effects are appreciable. In this paper the retardation of the wave‐front behind the position predicted by the inviscid shallow water theory is found.
Non‐associative constitutive laws for low porosity rocks
Authors: Senseny Paul E. , Fossum Arlo F. , Pfeifle Tom W. 
Published: August 2005

AbstractTwo simple constitutive laws appropriate for elastic–plastic deformation up to peak load of low porosity rocks are presented. Both laws account for mean stress dependence of yield hardening between yield and peak strength and non‐associative plastic straining. The two constitutive laws are based on the Mohr–Coulomb and the Mises–Schleicher yield criteria. The yield criteria are matched at axisymmetric compression and the relationships among the constitutive parameters are given. The parameters are then evaluated for two evaporite rocks anhydrite and polyhalite based on axisymmetric compression data. Comparison of predicted stress–strain laws with those measured in the laboratory show that these laws can be used for engineering analysis.
Computational procedures for non‐linear three‐dimensional analysis with some advanced constitutive laws
Authors: Siriwardane H. J. , Desai C. S. 
Published: August 2005

AbstractComputational procedures for implementing some constitutive models are described and introduced in three‐, and two‐dimensional finite element procedures; here variable moduli, Drucker–Prager, critical state and cap models are considered. Consistent numerical schemes are presented with applications to a number of example problems. These procedures can provide successful results with advanced constitutive laws for three‐dimensional analysis of a wide range of non‐linear problems.
A displacement discontinuity approach to modelling the creep behaviour of rock and its discontinuities
Authors: Crawford A. M. , Curran J. H. 
Published: August 2005

AbstractUsing the correspondence principle of viscoelasticity the Displacement Discontinuity Method has been extended to model the rate‐dependent behaviour of a jointed rock mass. The intact rock is assumed to behave as a linear viscoelastic material while, in general, a non‐linear rate‐dependent behaviour of the rock joints can be accounted for. A number of numerical examples are presented which illustrate the accuracy and potential of the method for analysing complex engineering problems.
The flexure of an infinite strip of finite width embedded in an isotropic elastic medium of infinite extent
Authors: Selvadurai A. P. S. 
Published: August 2005

AbstractThis paper examines the problem of the flexure of a strip of finite width which is embedded in bonded contact with an isotropic elastic medium of infinite extent. The analysis of the problem is applicable to flexible beams of narrow width which experience flexure only in the longitudinal direction. Numerical results are developed for the maximum flexural moment induced in the embedded beam due to the action of a concentrated force.
An investigation of numerical errors in the analysis of consolidation by finite elements
Authors: Reed M. B. 
Published: August 2005

AbstractA smoothing technique is developed to remove the oscillatory errors in initial nodal pore pressures, associated with the use of quadratic isoparametric elements to model soil consolidation. Numerical results using this technique are compared with the performance of other types of element in problems of one‐and two‐dimensional consolidation.
The effect of the plastic potential in boundary value problems involving plane strain deformation
Authors: Potts D. M. , Gens A. 
Published: August 2005

AbstractA large proportion of the constitutive models currently employed in Geomechanics are based on the theory of plasticity. Owing to the limitations of the data obtained from conventional testing equipment, arbitrary assumptions are often made about the behaviour of the material in generalized stress space.In this paper it is shown that the Lode angle of the stress state at failure in plane strain deformation is dependent on the shape adopted for the plastic potential. The influence of the shape of the plastic potential in the deviatoric plane on the predicted behaviour of two boundary value problems both prior to and at failure is then considered. In both cases a form of the Modified Cam Clay model is employed to describe the soil behaviour, and numerical predictions are obtained using a finite element computer code. For drained situations it is shown that the Lode angle of the stress state at failure has a dominating influence on the predicted behaviour. However, for undrained cases the effects are not so important as long as the correct undrained strength at failure is enforced.
Torsional surface waves in inhomogeneous elastic media
Authors: Vardoulakis I. 
Published: August 2005

AbstractThe dispersion of torsional surface waves in two types of inhomogeneous elastic media is discussed (1) in a half‐space with shear modulus varying linearly with depth and with constant density (Gibson'S half‐space) and (2) in a half‐space with shear modulus varying with the square‐root of the depth co‐ordinate and with constant density. Inhomogeneous media with constant shear wave velocity are also reviewed and the obtained solutions are discussed in relation to appropriate boundary conditions.
A finite difference method for measuring soil thermal diffusivity in situ
Authors: Coleman J. D. 
Published: August 2005

AbstractA method is devised for measuring soil thermal diffusivity in situ. It is based on direct experimental simulation of the finite difference approximation to the one‐dimensional heat conduction equation.The method does not require the soil to be homogeneous except between the three thermometers that are used, at depths z + d, z and z − d. Nor need the energy input curve be sinusoidal. However, it must be fairly smooth for the finite difference approximation to be accurate.Experimental results for London Clay are presented, obtained using thermometers at depths of 1, 6 and 11 cm to give a mean thermal diffusivity of 0.0074 cm2/s at a depth of 6 cm. This value is consistent with other estimates of diffusivity for clay soils.The method is capable of automation, and should be suitable for use on engineering sites, at low cost.The method is capable of generalization to other linear diffusion equations containing one independent parameter. The same limitation also applies to its application to constitutive or geometrical non‐linear one dimensional diffusion equations, and each equation requires individual study to assess feasibility of use of the method.The method in effect uses the usual finite difference approximation, not to prepare a numerical solution, but to design an experiment carried out essentially within the finite difference ‘molecule’. The measured parameter of the diffusion equation is the usable product of the method.
An approximate F.E. analysis of seepage with a free surface
Authors: Cividini Annamaria , Gioda Giancarlo 
Published: August 2005

AbstractAn approximate step‐by‐step procedure is presented for the finite element analysis of transient unconfined flow problems. At each step the free surface is modelled by means of segments coinciding with sides of the elements. This leads to an approximate but extremely simple solution scheme which can be readily incorporated into standard codes for confined analysis. The solutions of some significant problems are presented and compared with other non‐approximate solutions. They show that the technique, in spite of its approximation, is capable of giving meaningful results from an engineering viewpoint.
A statistically based numerical model for heat conduction in fractured rock masses
Authors: Gartling David K. , Thomas Robert K. 
Published: August 2005

AbstractA computational procedure for simulating heat conduction in fractured rock masses is proposed and illustrated within the context of the finite element method. The procedure makes use of simple local models for conduction in the vicinity of a single open fracture. The local models allow effective thermal properties for fractured rock to be expressed in terms of fracture characteristics such as spacing, orientation and aperture. The distributions of fractures and fracture properties within the finiteelement model are derived from a statistical representation of geological field data. The procedure is demonstrated to satisfactorily reproduce heat transfer results across single fractures and provide an efficient means of representing conduction in formations with multiple fractures.
A critical assessment of methods of correcting for drift from the yield surface in elasto‐plastic finite element analysis
Authors: Potts D. M. , Gens A. 
Published: August 2005

AbstractThe analysis of elasto‐plastic boundary value problems using the finite element method involves many discretizations. These lead to the problem of yield surface drift in which the stress state predicted at the end of an elasto‐plastic increment of loading does not lie on the current yield surface. As such discrepancies are comulative it is important to ensure that the stresses are corrected back to the yield surface during each increment of loading.In this paper five methods of accounting for this drift are examined. These involve correcting the stresses by projecting back along the plastic flow, the total strain increment and the accumulated effective stress direction. In addition a ‘correct’, method which accounts for the changes in elastic strains which accompany any stress correction is considered. This method is theoretically more sound than the other approximate approaches. All five methods have been used in finite element analyses of the stress changes that occur adjacent to a single pile installed in a uniform deposit of soil on pile loading. The soil was assumed to be normally consolidated and was modelled using a form of modified Cam Clay. Comparison of these results with an analysis, in which yield surface drift was negligible indicated that only the ‘correct’ method and the method involving projecting back along the plastic flow direction give accurate predictions. Substantiai errors occur if the other methods of correcting for yield surface drift are employed. It is recommended that the ‘correct’ method be adopted for finite element calculations.
A coupling scheme for boundary and finite elements using a joint element
Authors: Mitsui Y. , Ichikawa Y. , Obara Y. , Kawamoto T. 
Published: August 2005

AbstractA coupling scheme for boundary and finite elements using a joint element is proposed. The scheme is based on the finite element discretization (i.e. the equivalent FE procedure). Footing problems founded on multiple layers are solved. Furthermore, the scheme is extended to a non‐linear analysis.
An application of the calculus of variations to rectilinear flow of granular materials
Authors: Spencer A. J. M. , O'Mahony T. C. 
Published: August 2005

AbstractThe calculus of variations is an attractive tool for the determination of critical slip surfaces, but there are unresoived difficulties in its application to plane strain problems. Here we consider the simpler problem of rectilinear flow under gravity or other constant body force. In particular we investigate the stability of an infinitely long slope of finite width for material with cohesion and internal friction. From a variational formulation, the differential equation of the critical slip surface is formulated. An explict solution of this equation is obtained, and hence we determine the critical slope angle in terms of the width of the slope and the material properties. The results are compared with those of an earlier limit analysis treatment.
Viscoelastic analysis of piles and pile groups
Authors: Ahmad S. , Davies T. G. , Manolis G. D. 
Published: August 2005

AbstractThe axial and lateral load–displacement response of single piles and pile groups during the secondary consolidation (creep) phase of deformation is obtained by idealizing the soil as a linear viscoelastic material. The boundary element method is used to model the soil halfspace and the piles, which are assumed to behave elastically, are idealized as beam‐columns. By using the correspondence principle, the problem is solved in the Laplace transform domain and the final solution is obtained by numerical inversion of the transformed data. The salient features of the viscoelastic response are identified in several non‐dimensional plots which encompass the spectrum of geometrical and material parameters commonly encountered in practice. The results of the analysis compare favourably with the limited data available in the literature.
Linearization of in situ stress change formulae for gauges at arbitrary down‐hole orientation
Authors: Pariseau William G. 
Published: August 2005

AbstractThe vibrating wire stress gauge is a borehole device for measuring stress changes in situ. Three gauge arrays are required for determining changes in the secondary principal stresses. Standard data reduction formulae that use the principal axes for reference are in error because of possible changes in the principal directions. Data reduction formulae that allow for such changes and for arbitrary gauge orientations within an array are presented here. This is of considerable practical importance when installing gauges because of scheduling restrictions and hole irregularities that may preclude installation at the planned angles for which data reduction formulae exist. Linearization and thus direct inversion of the resulting system of equations, is achieved in a fixed but otherwise arbitrarily oriented Cartesian system of reference.
Transfer matrix approach for nonlinear pile group response analysis
Authors: Nogami Toyoaki , Paulson Stephen K. 
Published: August 2005

AbstractA transfer matrix method is applied for the analysis of non‐linear pile group responses. The expression for the transfer matrix is obtained by idealizing the non‐linear pile group as a group of piles attached to a piecewise linear “Winkler model for a pile group”. This Winkler idealization is essential to apply a transfer matrix method for the pile group response analysis. The parameters of this Winkler model can be defined from unit load transfer curves obtained for a single pile. In the limited studies carried out, it is found that the present approach predicts the response of pile groups reasonably well.