摘要:

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.

ISSN:0363-9061    

DOI:10.1002/nag.1610050202

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe quasi‐static development of the force, pore pressure and displacement is obtained in the system of a circular elastic pile partially embedded in a saturated porous elastic soil, and loaded axially on the top. The porous elastic soil is governed by Biot's theory. The problem is decomposed into two systems, namely, an extended porous elastic half‐space in the absence of the pile characterized by the material constants of the medium, and a fictitious pile represented by a Young's modulus equal to the difference between the Young's moduli of the real pile and the medium. The problem is found to be governed by a Fredholm integral equation of the second kind. Laplace transforms are applied to time functions involved, and Hankel transforms to the radial coordinate of which the origin is at the centre of the pile. Numerical solutions are obtained for final and initial solutions for various practical values of the parameters invol

ISSN:0363-9061    

DOI:10.1002/nag.1610050203

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

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 suitablelogarithmically 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 economi

ISSN:0363-9061    

DOI:10.1002/nag.1610050204

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe theoretical aspects of mining in rock subject to tectonic stressing are still insufficiently clear. While rock mechanics uses Heim's rule and assumes the virgin stress to be generally lithostatic, earth science resorts to the folding theory and to different approaches in explaining geological phenomena.In this paper, a procedure is proposed for determining tectonic stresses in mining ground below a surface fold, the latter being assumed to originate through local buckling of the surface layer under tectonic action. For the purpose of this hypothesis, the concept of displacement along the interface of the layer and the surrounding incompetent rock is defined. In the case of elastic or viscous incompetent rock, the induced stress is obtainable by an integral equation approach.A numerical technique was developed accordingly for the zone of contact strain, and special attention is paid to interpretation of the singular integrals representing the boundary stress. Numerical results are presented as an illustration.

ISSN:0363-9061    

DOI:10.1002/nag.1610050205

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractHeated salt mine room and pillar simulations have been performed to provide information regarding parameters affecting room closure rates to designers of radioactive waste isolation facilities. A coupled secondary creep and heat transfer formulation with large strain capabilities was used to assess the effects of variations in creep law parameters, thermal properties, imposed boundary conditions, temporal integration and meshing resolution on room closure rates. Results indicate that the greatest effect results from variations in parameters appearing in the creep constitutive equation.

ISSN:0363-9061    

DOI:10.1002/nag.1610050206

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

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 pos

ISSN:0363-9061    

DOI:10.1002/nag.1610050207

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractFor non‐linear dynamic problems, it has been recognized that an explicit time‐integration method of approach is a very efficient way of solving the dynamic equations of motion. The numerical formulation and computation for such problems fall into the two general categories of finite elements and finite differences. Over the years, there have been many arguments between schools which adopt the finite element approach and those which adopt the finite difference approach. At one extreme, arguments areconcerned with the superiority of each approach and at the other end of the spectrum the arguments are about which approach is a subset of the other. The most common of these arguments are concerned with efficiency and accuracy. This publication addresses the accuracy issue with specific reference to explicit calculations in which the analysis domain is discretized into triangular or quadrilateral plane‐strain elements. It concludes that if the same basic assumptions are made in the two approaches, they, will give identical answers for problems in this cat

ISSN:0363-9061    

DOI:10.1002/nag.1610050208

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610050209

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610050201

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY