Deformation prediction for anisotropic sand during the rotation of principal stress axes

107A and strain rate invariants. The stress strain relationships obtained are augmented by appropriate loading/unloading data, in accordance with the general behaviour of frictional materials. The theory can model all the important features of frictional material behaviour, including: the influence of all three stress invariants, coupling between deviatoric and frictional response, dilatancy, softening and different behaviour under loading and unloading. It contains a suprisingly large number of both classical and nonclassical theories as special cases. 873175 Penetration into dry porous reck Forrestal, M J lnt J Solids Struct V22, NI2, 1986, P1485-1500 Closed form solutions have been developed for the forces on projectiles penetrating geological targets. Constitutive target description consists of a linear hydrostat and a Mohr-Coulomb failure criterion with a tension cutoff. The model includes three regions of response, a plastic region, a radially cracked region, and an elastic region. At low enough penetration velocity, it is possible that no plastic region exists, so the elastic-cracked model was developed. Predictions from the model are in reasonable agreement with deceleration data from full scale field tests on dry tuff targets. 873176 Deformation prediction for anisotropic sand during the rotation of principal stress axes Miura, K; Toki, S; Miura, S Soils Found V26, N3, Sept 1986, P42-56 A constitutive model, the Multi-Directional Sliding Model, based on the concept that deformation behaviour of sand is governed ,by the sliding mechanism on infinite potential sliding planes, has been developed for cohesionless soils with anisotropic fabrics and mechanical properties. The model is applicable to the general stress condition, including arbitrary rotation of principal stress axes. It is verified against results of drained shear tests on sand in a hollow cylinder apparatus. 873177 Generalized elastoplastic constitutive model for clay in threedimensional stresses Nakai, T; Matsuoka, H Soils Found V26, N3, Sept 1986, P81-98 A simple generalized model is proposed which precisely describes the stress strain behaviour of clay under various stress paths. It incorporates the influence of the intermediate principal stress and of the stress path. Soil parameters may be easily determined, as only a yield function and a strain hardening parameter are used in the model. The model is verified against test results for clay under triaxial and plane strain conditions.

873178 Reck mass behaviour considering water flow and heat transfer Sato, M; Kamemura, K Proc 5th International Conference on Numerical Methods in Geomeclumics, Nagoya, 1-5 April 1985 V2, P703-710. Publ Rotterdam: A. A. Balkema, 1985 The interaction between deformation, heat flow and pore water flow in a rock mass is studied. A convective-conductive three phase problem is solved using finite element and finite

difference techniques with an implicit time integration scheme. The model is demonstrated with reference to stress, temperature, heat flow and pore pressure distribution around a tunnel. Numerical predictions and field measurements agree well.

873179 Numerical modelling of interfaces using conventional finite elements Griffiths, D V Proc 5th International Conference on Numerical Methods in Geomechanics, Nagoya, 1-5 April 1985 V2, P837-844. Publ Rotterdam: A. A. Balkema, 1985 The ability of 8-noded quadrilateral interface elements to model adhesive and frictional slippage has been examined. Elements are tested at various values of stiffness and aspect ratio. Four test cases are studied: plane strain analysis of inclined interfaces; laterally loaded footing in plane strain; laterally loaded circular footing; and earth pressure at rough or smooth walls. Elements often performed well, but for higher aspect ratios a tighter convergence tolerance in the plasticity algorithm was needed.

Design methods 873180 Computer-aided underground mine design model with a geological grid interface. Short communication' Chatterjee, P K; Scheck, D E; Chaluvadi, S; Holguin, S Int J Min Geol Engng V4, N4, Dec 1986, P319-329 The overall objective of this study was to develop an integrated computer-aided underground coal mine design procedure that will help maximise coal recovery at greatly reduced costs. The design layout is incorporated into a longwall and room and pillar simulation package that makes use of borehole data and other coal sample and drilling information to evaluate the layout. The economic evaluations of the different layouts generated by successive simulations are used to select the optimum layout.

873181 New design concept for arch dams taking into account seepage forces Gull, K; Wittke, W Rock Mech Rock Engng VI9, N4, Oct-Dec 1986, P187-204 A stability analysis of arch dams is described which takes into account the deformability of the rock mass and the forces induced by seepage through the rock mass. Three dimensional analysis shows that the interaction between dam and bedrock must be taken into account. Cracks located at the upstream side of the dam's base, as reported for several arch dams, can be explained by means of the analysis presented. Tensile stresses can be predicted when designing a dam and counteracted by appropriate measures. Stresses in the bedrock and in the concrete are shown to be favourably influenced by the choice of the grout curtain inclination.

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