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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>COMPUTING COSTS OF FEM ANALYSIS OF FOUNDATION ENGINEERING PROBLEMS AND POSSIBLE WAYS OF INCREASING EFFICIENCY</title>
      <link>https://trid.trb.org/View/269851</link>
      <description><![CDATA[The application of finite element methods (fem) to foundation engineering applications is often restricted by the available computer capacity and the computing costs. The purpose of this paper, therefore, is, to present test results and to discuss possible ways of achieving a substantial reduction in computing times.  Dividing the numerical analysis into the five levels -hardware, software, element-mesh and element-type, iteration technique (approximation of non-linearity) and constitutive model - one can show that the computing time can be reduced by about 20 per cent at every level.  In particular, the use of the modified Newton-Raphson method for approximation of non-linearity and the constitutive model -apart from the theoretical concept (elastoplastic, hypoelastic etc) -must be formulated in a manner which does not produce substantial changes in the coefficients of the material matrix caused by small stress changes.  On the whole, computing time can be reduced to about 10 per cent of present computing costs. Thus, it would even be economically viable to solve three-dimensional non-linear problems by fem.  (TRRL)]]></description>
      <pubDate>Fri, 27 Aug 2004 21:57:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/269851</guid>
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    <item>
      <title>VISCOELASTICITY ANALYSIS OF PILES AND PILE GROUPS</title>
      <link>https://trid.trb.org/View/269850</link>
      <description><![CDATA[The 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. (Author/TRRL)]]></description>
      <pubDate>Fri, 27 Aug 2004 21:57:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/269850</guid>
    </item>
    <item>
      <title>THREE DIMENSIONAL ANALYSIS OF SLOPE STABILITY</title>
      <link>https://trid.trb.org/View/269849</link>
      <description><![CDATA[A 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 homgeneous slopes are presented. (Author/TRRL)]]></description>
      <pubDate>Fri, 27 Aug 2004 21:57:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/269849</guid>
    </item>
    <item>
      <title>A MATHEMATICAL MODEL OF PERMEABILITY ALTERATION AROUND WELLS</title>
      <link>https://trid.trb.org/View/353092</link>
      <description><![CDATA[This paper presents an analytical solution of the permeability alteration problem around wellbore.  This alteration may be a permeability reduction due to drilling fluid invasion or mudcake formation around the wellbore. On the other hand, the alteration may be a permeability increase resulting from stimulation by acidizing the formation matrix around the well.  This permeability discontinuity in a reservoir forms a composite reservoir system.  With the composite model, both the degree and the radial extent of permeability alteration can be adequately predicted.  The conventional skin concept is inadequate and physically unrealistic in most of these cases.  This paper describes the application of an automatic weighted constrained least-squares parameter estimation technique and the analytical model for pressure transient analysis. The parameters of the composite reservoir system are determined from a match of the pressure transient data. The behaviour of the pressure transient in such composite systems is presented using the analytical solution.  (A)]]></description>
      <pubDate>Sun, 31 Mar 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/353092</guid>
    </item>
    <item>
      <title>IN-PLANE VIBRATIONS OF SOIL DEPOSITS WITH VARIABLE SHEAR MODULUS: 1. SURFACE WAVES</title>
      <link>https://trid.trb.org/View/353093</link>
      <description><![CDATA[The propagation characteristics of dispersive SV/P surface waves are analytically studied in a linear-elastic, isotropic, compressible half-space with constant mass density and Poisson's ratio and shear modulus increasing according to a continuous, bounded function of depth. Dispersion relations for the particular wave modes are evaluated over wide ranges of the parameters involved. Displacement profiles are presented for typical values of these parameters.  Finally, an equivalent depth is given for use in connection with steady-state vibration techniques for site investigation.  (A)]]></description>
      <pubDate>Sun, 31 Mar 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/353093</guid>
    </item>
    <item>
      <title>GENERALIZED PLASTICITY AND THE MODELLING OF SOIL BEHAVIOUR</title>
      <link>https://trid.trb.org/View/353094</link>
      <description><![CDATA[The paper outlines the theory of generalized plasticity in which yield and plastic potential surfaces need not be explicitly defined, and shows how a very effective general model describing the behaviour of sands and of clays under monotonic or transient loading can be developed.  The model is currently one of the simplest and yet one of the most effective ones for describing the full range of behaviour. The hierarchical structure of the model limits the number of parameters which have to be experimentally determined for a given material to those strictly necessary for the problem at hand.  A discussion of currently used models is included. (A)]]></description>
      <pubDate>Sun, 31 Mar 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/353094</guid>
    </item>
    <item>
      <title>VARIATIONAL PRINCIPLES AND FINITE ELEMENT METHOD FOR STRESS ANALYSIS OF POROUS MEDIA</title>
      <link>https://trid.trb.org/View/352360</link>
      <description><![CDATA[A number of variational principles are established in this paper for the stress analysis of porous media with compressible constituents.  A three-dimensional finite element method is proposed based on the variational principle.  The finite element method thus established is applied to the study of the temperature, deformation and flow field associated with the water-flood technique in secondary recovery projects for oil exploration.  In the study model, the layout of injection wells and production wells is considered to have a regular pattern where symmetry conditions exist.  The injection fluid diffuses slowly into the formation through a vertical crack which is initially generated by an explosion.  The problem is analysed by a plane strain formulation with the effects of heat conduction and convection included.(A)]]></description>
      <pubDate>Thu, 28 Feb 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/352360</guid>
    </item>
    <item>
      <title>A NUMERICAL PROCEDURE FOR SIMULATION OF HYDRAULICALLY-DRIVEN FRACTURE PROPAGATION IN POROELASTIC MEDIA</title>
      <link>https://trid.trb.org/View/352362</link>
      <description><![CDATA[A procedure for numerical approximation to two-dimensional, hydraulically-driven fracture propagation in a poroelastic material is described.  The method uses a partitioned solution procedure to solve a finite element approximation to problems described by the theory of poroelasticity, in conjunction with a finite difference approximation for modelling fluid flow along the fracture.  An equilibrium fracture model based on a generalized, Dugdale-Barenblatt concept is used to determine the fracture dimensions.  An important feature is that the fracture length is a natural product of the solution algorithm.  Two example problems verify the accuracy of the numerical procedure and a third example illustrates a fully-coupled simulation of fracture propagation.  Photographs taken from a high-performance engineering workstation provide insight into the nature of the coupling among the physical phenomena.(A)]]></description>
      <pubDate>Thu, 28 Feb 1991 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/352362</guid>
    </item>
    <item>
      <title>NUMERICAL SIMULATION OF EXCAVATION IN ELASTOPLASTIC SOILS</title>
      <link>https://trid.trb.org/View/307333</link>
      <description><![CDATA[A finite element method for simulating excavation in elastoplastic soils which produces a "unique" solution for any number of excavation stages is presented.  The proposed method satisfies the uniqueness principle for elastic materials postulated by Ishihara, and degenerates to the methods presented in the Adina code and by Brown and Booker and Ghaboussi and Pecknold for the simple elastic cases. The non-linear (elastoplastic) finite element equations are derived from a variational formulation which accounts for time-varying problem domain and boundaries.  The roots of these non-linear equations are solved by Newton's method, using the notion of the consistent tangent operator proposed by Simo and Taylor in conjunction with a numerical algorithm based on the "radial-return" concept for integrating stresses.  Numerical examples demonstrate that in the elastic case the solution to problems involving a "shrinking" (excavation) or "expanding" (fill) domain is superposable and does not depend on the number of construction stages.  For a monotonically shrinking elastoplastic domain and the von Mises and Drucker-Prager yield models, it is shown that the proposed method also produces a "unique" solution independent of the number of excavation stages.  Finally, the asymptotic quadratic convergence exhibited by the proposed method is demonstrated to show the efficiency engendered by the technique described.  (Author/TRRL)]]></description>
      <pubDate>Sat, 31 Mar 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/307333</guid>
    </item>
    <item>
      <title>PERFORMANCE OF FLEXIBLE RETAINING WALLS SUPPORTING DRY COHESIONLESS SOILS UNDER CYCLIC LOADS</title>
      <link>https://trid.trb.org/View/307334</link>
      <description><![CDATA[A finite element model is proposed for studying the seismic response of a flexible retaining wall/soil system.  The model accounts for nonlinear hysteretic soil behaviour, and also for the increase in lateral stresses and settlement related to grain slip caused by cyclic loads.  The response computed by the proposed method was compared with responses recorded at the Cambridge centrifuge facility, and found to be in reasonable agreement.  The model was then used to identify the importance of factors such as flexibility of the wall and relative density of the backfill.  The study reveals that the maximum bending moments given by current design procedures are nonconservative for stiffer walls. Deflections of flexible walls are of major concern. Flexible walls supporting a sand of medium density yield the greatest deflection.  (Author/TRRL)]]></description>
      <pubDate>Sat, 31 Mar 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/307334</guid>
    </item>
    <item>
      <title>BACK ANALYSIS PROCEDURES FOR THE INTERPRETATION OF FIELD MEASUREMENTS IN GEOMECHANICS</title>
      <link>https://trid.trb.org/View/283064</link>
      <description><![CDATA[A survey is presented of some recent developments of the numerical techniques for back analysis in the field of geomechanics, with particular reference to tunnelling problems.  In the spirit of Terzaghi's observational design method, these techniques are seen as practical tools for interpreting the available field measurements, in order to reduce the uncertainties that in many instances affect the parameters governing the solution of complex geomechanics problems.  Both deterministic and probabilistic viewpoints are considered and some significant applications to practical problems are illustrated.  (Author/TRRL)]]></description>
      <pubDate>Sun, 31 Jul 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/283064</guid>
    </item>
    <item>
      <title>FLOW THROUGH POROUS MEDIA: A PROCEDURE FOR LOCATING THE FREE SURFACE</title>
      <link>https://trid.trb.org/View/283065</link>
      <description><![CDATA[A finite element procedure is developed to accurately locate the free surface of unconfined seepage flow through porous media.  The free surface is taken as the boundary between wet and dry soils, with flow in the saturated region characterized by Darcy's law.  The method involves equations and meshing which are fully consistent with a general formulation for geotechnical engineering problems involving simultaneous solution of pore fluid pressures and soil skeleton displacements.  Accuracy and versatility of the proposed procedure are demonstrated by solving various unconfined seepage flow problems through earth structures. Free surfaces and flownets are presented for the calculated flow fields.  (Author/TRRL)]]></description>
      <pubDate>Sun, 31 Jul 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/283065</guid>
    </item>
    <item>
      <title>AXIAL AND LATERAL RESPONSE OF PILE GROUPS EMBEDDED IN NON-HOMOGENEOUS SOILS</title>
      <link>https://trid.trb.org/View/283066</link>
      <description><![CDATA[A numerical method of analysis based on elasticity theory is presented for the analysis of axially and laterally loaded pile groups embedded in nonhomogeneous soils.  The problem is decomposed into two systems, namely the group piles acted upon by external applied loads and pile-soil interaction forces, and a layered soil continuum acted upon by a system of pile-soil interaction forces at the imaginary positions of the piles.  The group piles are discretized into discrete elements while the nonhomogeneous soil behaviour is determined from an economically viable finite element procedure.  The load-deformation relationship of the pile group system is then determined by considering the equilibrium of the pile-soil interaction forces, and the compatibility of the pile and soil displacements.  The influence of soil nonlinearity can be studied by limiting the soil forces at the pile-soil interface, and redistributing the "excess forces" by an "initial stress" process popular in elasto-plastic finite element analysis. The solutions from this approach are compared with some available published solutions for single piles and pile groups in homogeneous and nonhomogeneous soils.  A limited number of field tests on pile groups are studied, and show that, in general, the computed response compares favourably with the field measurements.  (Author/TRRL)]]></description>
      <pubDate>Sun, 31 Jul 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/283066</guid>
    </item>
    <item>
      <title>DYNAMIC ANALYSIS OF PILES AND PILE GROUPS EMBEDDED IN NON-HOMOGENEOUS SOILS</title>
      <link>https://trid.trb.org/View/281817</link>
      <description><![CDATA[A hybrid boundary element formulation for the steady state analysis of piles and pile groups embedded in a soil stratum in which the modulus increases linearly with depth is presented.  The piles are represented by compressible columns or flexible beams and the soil as a hysteretic, layered medium.  The explicit Green's function corresponding to dynamic loads in the interior of a layered stratum, developed earlier by Kausel is used in the study.  The governing differential equations for the pile domain are solved for a distributed periodic loading intensity and those for the soil domain by a system of boundary elements at the pile-soil interface.  These are then assembled into a system of algebraic equations by satisfying interface equilibrium and compatibility. The results of the analysis have been compared against those from alternative formulations, e.g. finite elements, and confirm the accuracy of the proposed formulation. Representative results for single piles and pile groups are presented.  (Author/TRRL)]]></description>
      <pubDate>Thu, 31 Mar 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/281817</guid>
    </item>
    <item>
      <title>TORSIONAL STIFFNESS OF NON-UNIFORM AND HOLLOW RIGID PIERS EMBEDDED IN ISOTROPIC ELASTIC MEDIA</title>
      <link>https://trid.trb.org/View/281818</link>
      <description><![CDATA[This 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 mismatch between the layer and the underlying half space.  (Author/TRRL)]]></description>
      <pubDate>Thu, 31 Mar 1988 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/281818</guid>
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