摘要:

AbstractA computational technique for earth penetration is presented which includes the direct coupling between the deformable target model and a deformable model of the penetrator. In this fully Lagrangian approach, both the target and penetrator are discretized to represent the anticipated terradynamic and structural responses. A sliding interface is used between the two models to provide the time‐dependent terradynamic‐to‐penetrator interaction. This technique has the unique advantage of including the target‐to‐penetrator interaction in one calculation in a continuous and consistent manner. Comparisons of calculated penetration with full‐scale field test dat

ISSN:0363-9061    

DOI:10.1002/nag.1610120302

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractDeficiencies of different existing models on ‘Reservoir Induced Seismicity’ have been discussed and a new mathematical model, which enhances a better understanding of triggering mechanism in terms of changes in effective stresses,in situstresses and water level variations, has been discussed in this paper. In the model fractured rock is simulated by a fluid‐filled elastic material subject to Mohr–Coulomb failure criterion. The model has been found to be capable of responding effectively to site specific attributes. It can recognize and explain the phenomenon of time lag observed in several actual cases. It is also capable of simulating stabilization of rock–reservoir system after a period of activities that follow the initial stage of filling. One dimensional and two dimensional, isotropic and anisotropic cases have been analysed and the model predictions have been found to agree qualitatively with the field obs

ISSN:0363-9061    

DOI:10.1002/nag.1610120303

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractTo determine moisture movement and heat transfer through an unsaturated soil under temperature and volumetric water content gradients, it is necessary to have knowledge of phenomenological coefficients of the soil. However, in unsaturated flow, i.e. flow through unsaturated soil, these phenomenological coefficients are not constants, but vary with volumetric water content as well as temperature. In this paper, an identification technique is proposed for evaluation of the phenomenological coefficients. The phenomeno‐logical coefficients are first assumed to be certain kinds of functions of volumetric water content and temperature. The choice of the functional forms is based on an understanding of the physical situation, and previous knowledge of water flow in the isothermal case. The constant parameters associated with the functional forms are evaluated through the use of the identification technique. Once these phenomenological coefficients are obtained as certain functions of the volumetric water content and the temperature for a specified soil, analysis of coupled moisture flow and heat transfer in the unsaturated soil can procee

ISSN:0363-9061    

DOI:10.1002/nag.1610120304

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractWave propagation problems, such as blasting for excavation of a new tunnel oriented perpendicular to an existing tunnel, are truly three dimensional in nature. Dynamic finite element analysis with three‐dimensional elements is, however, very expensive. The cheaper and simpler alternative would be to model the problem approximately in two dimensions. This paper shows that dynamic finite element analysis of such problems using conventional two‐dimensional plane strain elements produces responses which are erroneously excessive. This is accredited to the inability to the inability of the two‐dimensional elements to correctly model the rapid attenuation of the amplitudes of the outward propagating waves. To overcome this problem, a pseudo‐plane strain concept is introduced and has been found to be a viable alternative. Numerical results are presented to demonstrate the application of the

ISSN:0363-9061    

DOI:10.1002/nag.1610120305

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe concept that the flow of granular materials is governed by shear on certain critical planes is used to formulate an elastic–plastic model. When the elastic strains are neglected, the Double Shearing model becomes identical to the rigid‐plastic model of de Josselin de Jong which he named the Double Sliding model. After a discussion of the model, the small strain formulation is used to describe general boundary‐value problems. A comparison is then made between the coaxial Mohr–Coulomb yielding and the Double Shearing model on the basis of several numerical simulations. The non‐coaxiality of the axes of principal plastic strain rate and principal stress in the Double Shearing model leads to essentially different behaviour for stress rotations in comparison to the coaxial model. The Double Shearing model predicts in general lower limit loads because, for a given state of stress, it allows for several possible directions of plastic flow rather than a unique direction which derives from a plastic

ISSN:0363-9061    

DOI:10.1002/nag.1610120306

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractKinematic approach of limit analysis is applied to stability of an infinite, homogeneous, free‐of‐surcharge slope of soil with a nonlinear Mohr–Coulomb yield condition. On operating with a linear yield condition that exceeds the actual nonlinear condition, upper bounds to stability factors are constructed. The solutions overestimate by less than 1% the stability factors given by Zhang and Chen1for a nonlinear cond

ISSN:0363-9061    

DOI:10.1002/nag.1610120307

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610120308

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610120309

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610120301

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY