bluuebunny/crossref_metadata_2025_split huggingface dataset:
Approximate time‐dependent analysis of tunnel support structure considering progress of tunnel face
Authors: Sakurai Shunsuke 
Published: August 2005

AbstractThe pressure acting on tunnel support structures generally increases with lapse in time. The pressure increase may be caused by not only the time‐dependent mechanical properties of the underground medium, but also by the progression of the tunnel face. In order to clarify these two effects, three‐dimensional analysis is required. In this study, however, a method which takes into account the three‐dimensional effects of the tunnel face progression in two‐dimensional plane strain analyses is proposedby introducing the ‘equivalent intial stress’. The proposed method can be easily applied to time‐dependent analyses of the behaviour of tunnel support structures installed in a visco‐elastic medium.The tunnels considered here are circular in shape, being driven in homogeneous isotropic linear visco‐elastic media having hydrostatic initial stresses.In the first part of this paper, detailed discussions of the proposed equivalent initial stress are given. The second deals with the mathematical formulations for obtaining closed‐form solutions for the pressure acting on tunnel support structures. In the third, numerical results and discussions are given, and special attetion is paid to the effects of both the time‐dependent mechanical properties of the material and the tunnel face progression. Finally, the theoretical results obtained here are utilized for interpretation of field measurements.
An anisotropic hardening model for soils and its application to cyclic loading
Authors: Mrǒz Z. , Norris V. A. , Zienkiewicz O. C. 
Published: August 2005

AbstractAn anisotropic hardening model for soils is proposed by applying the concept of a field of hardening moduli developed previously for metals. Besides the yield surface, a set of nesting surfaces in the stress‐space specifies the variation of hardening moduli during the deformation process. Both drained and undrained soil behaviour can be treated and distortional as well as volumetric strain cycles can be considered. The model can be applied in studying soil behaviour under cyclic loading and in particular to describe densification or liquefaction phenomena.
A rate‐type constitutive model for soil with a critical state
Authors: Davis R. O. , Mullenger G. 
Published: August 2005

AbstractA continuum representation for soil which incorporates the concepts of hypoelasticity and critical state theory is proposed. General, three‐dimensional constitutive equations are formulated to relate specific volume, stress, rate of deformation and rate of change of stress, resulting in a mathematical material model which exhibits phenomenological features typical of soil response. The general constitutive equations are specialized to represent the particular cases of isotropic compression, constant, volume deformation, uniaxial compression and biaxial deformation. Methods are suggested for determining the model parameters to represent a specific soil using conventional triaxial test data. Comparisons of stress‐strain response with published experimental data are shown.
Effects of driving and subsequent consolidation on behaviour of driven piles
Authors: Desai C. S. 
Published: August 2005

AbstractThe effects and simulation of driving of structures (piles) into saturated soil media are discussed, and procedures for numerical simulation of driving are proposed. Consolidation caused by changes in stresses and in pore water pressures in the soil mass due to the driving is solved by using a finite element procedure. The changes in stresses and pore water pressures due to driving are obtained on the basis of the cavity expansion approach, and are introduced in the finite element procedure as initial conditions. Stresses and deformations around a pile as consolidation proceeds are plotted and related to the quantities such as a wall friction, and point and total loads relevant to analysis and design.
Finite element free surface seepage analysis without mesh iteration
Authors: Bathe Klaus‐Jürgen , Khoshgoftaar Mohammad R. 
Published: August 2005

AbstractAn effective solution procedure for the finite element analysis of free surface seepage problems is presented. The solution algorithm employs a non‐linear permeability description of the material and avoids iteration with the finite element mesh. The results and experiences obtained in the analyses of some problems are presented to demonstrate the usefulness of the technique.
A method of analysis for horizontally embedded anchors in an elastic soil
Authors: Rowe R. K. , Booker J. R. 
Published: August 2005

AbstractA general method is presented for the analysis of horizontally embedded anchors in an elastic soil. Provision is made in the analysis for the consideration of anchor shape, layer depth, anchor–soil interface condition, breakaway of the anchor from the underlying soil and interaction between groups of anchors.Application of the analytical technique is illustrated for strip and circular anchors, and these solutions are presented in the form of influence charts which may be used directly in hand calculations to predict the elastic load deflection behaviour, of anchor plates for a wide variety of material and geometric conditions.
On the estimation of the deformability characteristics of an isotropic elastic soil medium by means of a vane test
Authors: Selvadurai A. P. S. 
Published: August 2005

AbstractThe conventional use of the shear vane test is primarily restricted to thein‐situmeasurement of the undrained shear strength characteristics of saturated cohesive soils. Scant attention has been devoted to the use of this test as a means of measuring further properties of geotechnical interest. This paper presents an analytical study which illustrates the possible use of a shear vane test as a technique for the measurement ofin‐situdeformability characteristics of a soil medium. Certain plausible assumptions have been invoked for the analytical treatment of the shear vane problem. The vane blades are represented as elliptical shapes, the soil disturbance associated with the vane penetration is neglected and the soil mass enclosedwithin the swept boundary of the vane is represented as a rigid region. These, together with assumptions of classical isotropic elastic soil behaviour, enable the development of certain exact solutions for the torque–twist relationships of vanes fully or, partially embedded in the soil. The results indicate that the elastic deformability characteristics of a soil medium can be directly recovered from an examination of the initial stages of an experimental torque–twist curve. In particular, the measured parameter would correspond to the linear elastic shear modulus of the soil medium.
Finite element models for rock fracture mechanics
Authors: Ingraffea Anthony R. , Heuze Francois E. 
Published: August 2005

AbstractA finite element model for the prediction of discrete fracture propagation in rock structures loaded in compression is presented. The model integrates any one of three theories for mixed‐mode fracture initiation; it contains an energy balance algorithm for predicting crack increment length, and incorporates recent developments in finite element stress‐intensity factor computation. The predictions of the model are compared with the observed fracture response of a real rock structure. Results show that the model accurately predicts both stable and unstable fracture progagations observed experimentally.
Settlement of inhomogeneous consolidating soils—I: The single‐drained layer under confined compression
Authors: Mahmoud M. S. , Deresiewicz H. 
Published: August 2005

AbstractThe settlement and excess pore pressure are calculated for a column of water‐saturated clay in which the permeability and/or shear modulus vary with depth. Several fairly general laws of variation are investigated. In each case, the soil is assumed to have a permeable top surface and to rest on an impervious substrate.For all the variations examined, in which the shear modulus increases with depth below the surface but the permeability of the soil remains constant, the deflection at a given instant after imposition of the load decreases and the degree of settlement increases with increasing rate at which the change with depth takes place. It is found that, when the variation over the height of the column is one order of magnitude or less, the curve of degree‐of‐consolidation versus time is reasonably wellapproximated by the curve for a homogeneous soil whose modulus equals the depth‐averaged value. When, in addition, the permeability decreases with depth, the approximation becomes less accurate.The same approximation, for moderate increase in shear modulus with depth, predicts satisfactorily the process of dissipation of excess pore pressure at a given depth, but breaks down when the variation in modulus is large.Finally, it is shown that the effect of variable modulus on the settlement is greater than of a comparable variation in permeability.
Shear band inclination and shear modulus of sand in biaxial tests
Authors: Vardoulakis I. 
Published: August 2005

AbstractThe spontaneous shear band formation in the biaxial test on dry sand samples with constant cell pressure is treated as a bifurcation problem. The constitutive response of sand is described in terms of mobilized friction and dilatancy. Dilatancy is looked upon as an internal constraint and the hardening rule is expressed in terms of an adequate dimensionless stress measure. Owing to fail of normality in sand, localization always occurs in the hardening regime. The theoretical solution of the shear band inclination is a geometrical mean of the classical Coulomb and Roscoe solutions and is in good agreement with the experimental data. The incipient shear modulus is proportional to the stress level and can be estimated to be also proportional to these cant modulus.
Vertical and horizontal land deformation due to fluid withdrawal
Authors: Safai Nader M. , Pinder George F. 
Published: August 2005

AbstractA non‐linear distribution of vertical displacement versus aquifer depth is calculated in the case of a partially penertrating well. For a fully penetrating well, however, a linear distribution is observed. The solution exhibits a vertically uniform horizontal displacement in the case of a fully penetrating well and, for a partially penetrating well, the maximum horizontal displacement occurs at the elevation of the well bottom.
Stability properties of the Newmark, Houbolt and Wilson θ methods
Authors: Gladwell Ian , Thomas Ruth 
Published: August 2005

AbstractThis paper analysis the stability of several methods for obtaining numerical solutions of second‐order ordinary differential equations. The methods are popular in structural and geotechnical engineering applications and are direct, that is they do not require the transformation of the second‐order equation into a first‐order system. They include Newmark's method in both implicit and explicit forms, Wilson's θ‐method, Houbolt's method and some variants on this latter method. We shall examine the stability of the methods when applied to the second‐order scalar test equation

where a and c are real.
Vertical vibrations of a rigid circular body on a non‐homogeneous half‐space interrupted by a frictionless plane
Authors: Awojobi A. O. 
Published: August 2005

AbstractAn exact formulation is presented for the problem of a rigid circular body performing harmonic vibrations on an elastic half‐space whose shear modulus increases linearly with depth and is interrupted at some finite depth by a frictionless horizontal plane. The static case is derived in the limit of zero frequency vibrations while the known result for the uninterrupted half‐space is recovered in either extreme limit of the horizontal frictionless plane coinciding with the surface or when it is pushed down to an infinite depth.It is shown that the maximum effect of the interruption occurs when the frictionless plane is at a depth where the shear modulus is about 1·6 times the surface shear modulus. Furthermore, this maximum effect is equivalent to a reduction of about 5 per cent of the surface shear modulus or a reduction of about 2½ per cent in the natural frequency of the rigid body on an uninterrupted half‐space. The important conclusion, therefore, is that irrespective of the depth at which a half‐space isso interrupted, the surface shear modulus is still the dominant parameter and that both the increase in shear modulus with depth and the interruption are not only secondary but also opposing effects.
Stress analysis of a deep rigid axially‐loaded cylindrical anchor in an elastic medium
Authors: Luk V. K. , Keer L. M. 
Published: August 2005

AbstractThe elastostatic problem of an infinite elastic medium containing an axially‐loaded rigid cylindrical inclusion is investigated. This problem is of interest in connection with the geotechnical study of the time‐independent, load‐deflection characteristics of deep rigid anchors embedded in cohesive soil or rock media. The problem is formulated by means of Hankel integral transforms and reduced to a system of four coupled sing ular integral equations, where the unknown quantities are the normal and the shear stresses acting on the entire surface of the anchor. Numerical solutions are investigated for various Poisson's ratios and several values of the aspect ratio of radius to length of the cylindrical anchor.
A finite element method for studying the transient non‐linear thermal creep of geological structures
Authors: Anderson C. A. , Bridwell R. J. 
Published: August 2005

AbstractA finite element theory, suitable for describing the long‐term transient thermal creep of geomechanical structures where the material obeys an arbitrary type of creep law, is presented. The method takes into account large deformation effects, is stable for the large time steps required to model geophysical phenomena and accurately simulates changing, incompressible, plastic flow fields. Applications of the theory to the prediction of long‐term creep and creep rupture of simple engineering structures, are given. The theory is also applied to predict the thermal creep of layered media to study the mechanics of folding and rift formation.
The elastic response of multiple underream anchors
Authors: Rowe R. K. , Booker J. R. 
Published: August 2005

AbstractA technique is developed for the analysis of multiple underream anchor systems resting in an elastic soil. This technique may be used to consider anchor systems involving arbitrary anchor inclination and depth beneath the soil surface, as well as arbitrary number, shape, size and spacing of underreams. The approach is largely analytical in nature and involves only a fraction of the computation required for a finite element analysis.Consideration is given to the effects of anchor depth and inclination to the soil surface, and the spacing and number of underreams upon the elastic response of anchor systems. On the basis of the result from this study, a simple, approximate method for estimating the response of multiple underream anchors is proposed. This approach involves the use of several interaction charts, which are presented in the paper, and can be used as a hand method for estimating the load–displacement behaviour of quite general anchor systems to sufficient accuracy for most practical purposes. The use of the approximate approach is illustrated by an example.
A general basis for yield, failure and potential functions in plasticity
Authors: Desai C. S. 
Published: August 2005

AbstractA new concept based on the use of a function expressed as a (complete) polynomial expansion in terms of the three invariants of the stress tensor is proposed for deriving yield, failure and plastic potential functions for use in plasticity based constitutive laws. A mathematical interpretation and physical meaning of the proposed concept are provided by using the idea of the singular nature of constiutive matrices in incremental hypoelastic laws. It is suggested that the proposed function and (polynomial) forms of material moduli can be synonymous. A number of specialized forms of the general function are adopted and their values at failure from advanced three‐dimensional tests for a number of (geological) media are evaluated. The results indicate the possibility that there exist invariant numbers associated with the functions(s) that may apply to a wide range of materials. Some ideas on implementation of the proposed concept are also presented.
A novel finite element method for seepage analysis
Authors: Nath B. 
Published: August 2005

AbstractA novel finite element method has been proposed in this paper for the solution of seepage problems economically and accurately. In this method the governing equation and the prescribed boundary conditions are transformed so that they refer to a suitable logarithmically condensed ‘image’ space; the physical problem domain is also mapped into the image space. The transformed equation is then solved in the image space using standard finite elements, subject to the transformed boundary conditions. Because physical space is logarithmically condensed in the image space, the proposed method is capable of dealing with large or very large aspect ratio seepage problems economically and accurately.The validity of the method has been demonstrated by means of a number of examples including anisotropy and non‐linearity. In all cases an excellent degree of accuracy was achieved, efficiently and economically.
Mathematical model for one‐dimensional desiccation and consolidation of sedimented soils
Authors: Casteleiro Manuel , Krizek Raymond J. , Edil Tuncer B. 
Published: August 2005

AbstractA mathematical model has been developed to represent the physical phenomena that occur during the desiccation and one‐dimensional consolidation of successive layers of hydraulically transported sediments as they are periodically deposited in a containment area. The governing boundary value problem, defined in terms of pore water pressures, consists of two field equations (one for the saturated domain and one for the unsaturated domain), a drainage boundary condition, an evapotranspiration boundary condition and a series of continuity conditions at the interfaces between different layers. A number of simplifying assumptions were made to render the field equations tractable, and a step‐by‐step numerical procedure was used to solve the linearized boundary value problem; at the end of each step, the errors introduced by the simplifying assumptions were corrected. Based on a thorough study of the convergence and stability conditions associated with the numerical approximation employed, a system of automatic corrections was incorporated into the computer program to reduce the time increment if stability problems originate during the solution. Based on the results of a parameter study, it was found that, although drainage conditions at the bottom of the, layer do exert some influence on the consolidation rate during deposition of the dredgings, the evapotranspiration potential renders this effect almost negligible when desiccation takes place at the surface. In contrast, transpiration plays an important, role on the consolidation rate during the early stages of desiccation, but its effect is reduced considerably as the water table approaches an equilibrium position.
Non‐linear analysis of a joint element and its application in rock engineering
Authors: Xiurun (Ke Hsu‐Jun) Ge 
Published: August 2005

AbstractIn this paper models are given for analysis and description of non‐linear properties of joints, weak intercalations and interfaces in rock masses.Models for analysis consist of four parts, i.e. shear displacement model, normal deformation model, shear strength model and a relationship between unit shear stiffness and normal stress.The method of non‐linear analysis given in this paper is based on an incremental procedure.The proposed method is available for different types of shear‐displacement curves, and also adapted to the complicated process of loading‐unloading‐reloading.The results of computer simulation of an in‐situ shear test obtained by this method gave a good fit to the measured data.The method of non‐linear analysis of joint elements has been used in some practical rock engineering problems, and some interesting results and conclusions have been obtained.
Finite element method for time‐dependent problems of frozen soils
Authors: Klein Joachim 
Published: August 2005

AbstractGround freezing technology is favoured in civil engineering, mainly in tunnelling. The time‐dependent material characteristics in the form of creep control the bearing capacity of any frozen earth support system. The finite element method in connection with an initial strain algorithm is able to include these effects. The information about stress redistribution and deformation rate is important for an economic design. Case histories of different tunnel linings in frozen soil and two other examples of realized projects show the usefulness of such a procedure.
Non‐linear elastic finite element analysis of lateral earth pressures against basement wall
Authors: Roth W. H. , Crandall Leroy 
Published: August 2005

AbstractPerhaps the most widely used non‐linear elastic soil behaviour law uses the hyperbolic functions to define tangent modulus and Poisson's ratio versus strain.1,2 This paper presents the results of analytical studies with the hyperbolic elastic finite element technique for the prediction of static earth pressures against a 10‐story basement wall. Carefully performed laboratory tests of the backfill material and measurements of earth pressures during backfilling provided the basis fora, refinement of the current hyperbolic elastic method. The refined analysis resulted in closer agreement of calculated earth pressures with measured values.
A theoretical estimate of the tilt of a surface foundation due to an inclined anchor load applied at the interior of the soil medium
Authors: Selvadurai A. P. S. 
Published: August 2005

AbstractThis paper examines the problem of the interaction between a loaded rigid circular foundation located at the surface of an isotropic elastic halfspace and an inclined concentrated anchor load which is located at a finite depth along the axis of symmetry. Such inclined loads can be induced by, for example, anchor regions supporting earth retaining structures. The loaded rigid circular foundation resting in smooth contact with the elastic soil mass experiences a displacement and a tilt due to the action of the inclined anchor load. The magnitude of the rotational settlement is evaluated in exact closed form.
The consolidation of a soil stratum, including self‐weight effects and large strains
Authors: Lee Kuantsai , Sills G. C. 
Published: August 2005

AbstractA layer of fill deposited in a soft wet condition will consolidate under its own weight and will commonly undergo comparatively large strains in the process. Neither of these aspects of behaviour can be modelled by traditional consolidation theories. In this paper, a consolidation model is developed from the theory proposed by Gibson et al.5 and is applied here to soil consolidation during and after soil deposition. No restriction is made on the magnitude of strain, so that the boundaries are not taken as being fixed in space, but are allowed to move as required by the process of consolidation. However, perhaps the more important aspect is the consideration of self‐weight, since in many instances, the surface loading applied to soft, soils is small, and the majority of the compression of the layer occurs while the effective stresses reach equilibrium with the weight of the soil. Although some idealizations have to be made in assuming relationships between soil parameters, it is shown that the self weight effects in consolidation can be significant, and fundamental to an understanding of soft soil behaviour.