摘要:

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

ISSN:0363-9061    

DOI:10.1002/nag.1610090302

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

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.

ISSN:0363-9061    

DOI:10.1002/nag.1610090303

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

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 liter

ISSN:0363-9061    

DOI:10.1002/nag.1610090304

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

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 sugg

ISSN:0363-9061    

DOI:10.1002/nag.1610090305

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe application of finite element methods (FEM) 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‐l

ISSN:0363-9061    

DOI:10.1002/nag.1610090306

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe vibrating wire stress gauge is a borehole device for measuring stress changesin 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.

ISSN:0363-9061    

DOI:10.1002/nag.1610090307

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractWhen soils are considered as elastoplastic materials the elastic moduli are much higher than the plastic one(s). However the amount of elastic strain cannot be disregarded as it appears when undrained loading occurs. Based on experimental or theoretical observations, a number of elastic models with stress dependent moduli have been proposed. Attention is focused here on the consequences of this stress dependency on the recoverability of strain and work done after a closed stress path. A necessary and sufficient condition for an elastic material to be hyperelastic is given and the way to obtain practical solutions is shown on examples. The study is restricted to isotropic material undergoing small strains.

ISSN:0363-9061    

DOI:10.1002/nag.1610090308

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610090309

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610090310

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610090301

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY