摘要:

AbstractA method is devised for measuring soil thermal diffusivityin situ. It is based on direct experimental simulation of the finite difference approximation to the one‐dimensional heat conduction equation.The method does not require the soil to be homogeneous except between the three thermometers that are used, at depthsz+d,zandz−d. Nor need the energy input curve be sinusoidal. However, it must be fairly smooth for the finite difference approximation to be accurate.Experimental results for London Clay are presented, obtained using thermometers at depths of 1, 6 and 11 cm to give a mean thermal diffusivity of 0.0074 cm2/s at a depth of 6 cm. This value is consistent with other estimates of diffusivity for clay soils.The method is capable of automation, and should be suitable for use on engineering sites, at low cost.The method is capable of generalization to other linear diffusion equations containing one independent parameter. The same limitation also applies to its application to constitutive or geometrical non‐linear one dimensional diffusion equations, and each equation requires individual study to assess feasibility of use of the method.The method in effect uses the usual finite difference approximation, not to prepare a numerical solution, but to design an experiment carried out essentially within the finite difference ‘molecule’. The measured parameter of the diffusion equation is the usable product of t

ISSN:0363-9061    

DOI:10.1002/nag.1610080602

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe pressure versus settlement response is highly non‐linear for soils, in general. In the present study, a cubic equation of the typep=K1w−K2w3is suggested to incorporate the non‐linear behaviour. A trapezoidal footing with constant depth resting on a subgrade having non‐linear response is analysed. The resulting fourth order non‐linear differential equation with variable coefficients is solved by using the Galerkin technique and beam characteristic functions are employed to obtain faster convergence. The results are presented in the form of non‐dimensional charts for valid ranges of footings and soil

ISSN:0363-9061    

DOI:10.1002/nag.1610080603

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA number of computations have been performed in order to gain an insight into whether or not the non‐linear finite deformation theory must be applied in consolidation problems. These numerical experiments were preluded by tests to determine the correct model size and the fineness of the discretization. For this an analytical solution served as a gauge. The conclusion is that with stiffnesses of the order of ten times the external load, moderate deviations appear in both the effective stresses and the pore pressure

ISSN:0363-9061    

DOI:10.1002/nag.1610080604

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAn approximate step‐by‐step procedure is presented for the finite element analysis of transient unconfined flow problems. At each step the free surface is modelled by means of segments coinciding with sides of the elements. This leads to an approximate but extremely simple solution scheme which can be readily incorporated into standard codes for confined analysis. The solutions of some significant problems are presented and compared with other non‐approximate solutions. They show that the technique, in spite of its approximation, is capable of giving meaningful results from an engineering view

ISSN:0363-9061    

DOI:10.1002/nag.1610080605

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA computational procedure for simulating heat conduction in fractured rock masses is proposed and illustrated within the context of the finite element method. The procedure makes use of simple local models for conduction in the vicinity of a single open fracture. The local models allow effective thermal properties for fractured rock to be expressed in terms of fracture characteristics such as spacing, orientation and aperture. The distributions of fractures and fracture properties within the finiteelement model are derived from a statistical representation of geological field data. The procedure is demonstrated to satisfactorily reproduce heat transfer results across single fractures and provide an efficient means of representing conduction in formations with multiple fractures.

ISSN:0363-9061    

DOI:10.1002/nag.1610080606

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe analysis of mechanisms which could control the growth of fractures in non‐homogeneous regions is of paramount importance. One such mechanism is the behavior of the fracture as it reaches a frictional interface; coupled with this is the question of re‐initiation, e.g. whether a fracture can be contained within the region of initiation. Though the problems of slippage have been dealt with by other investigators, the present paper gives a more comprehensive picture and detailed treatment: effects of various frictional models at an interface are considered for a crack which intersects it at any angle; specialization then allows comparison with existing results in the literature.The problem of re‐initiation, after slippage has occurred at a frictional interface, is also considered, using two different models. First, by introducing microcracks in the adjacent stratum and looking at the effects on propagation criteria and, secondly, by examining the actual distribution of the stress tangential to the slip surface; detailed computations are performed and a simple criterion for re‐initiation is given, relating the re‐initiation stress dominantly to the confining stress on the

ISSN:0363-9061    

DOI:10.1002/nag.1610080607

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610080608

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610080609

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0363-9061    

DOI:10.1002/nag.1610080601

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY