Modelling failure of natural rock columns

PROPERTIES:DEFORMATION however, in the loess soil tested some restrictions occur. (from Authors) 967080 Experiments on surface deformation arising from a subsurface fracture Gang Wang, M. B. Dusseault & J. T. Pindera, Canadian Geotechnical Journal, 32(6), 1995, pp 1024-1034. Contains the results of a set of experiments on surface deformation arising from a pressurized fracture, using laser holography and Fizeau interferometry of noncontacting techniques to precisely sample the displacement field above a scale model. The results are remarkably accurate and consistent, and compare reasonably well with analytical and numerical model predictions. The techniques have potential applications in geomechanics and geotechnical engineering for laboratory study of various linear and nonlinear problems. (from Authors) 967081 Modelling failure of natural rock columns B. B. Hall, Geomorphology, 15(2), 1996, pp 123-134. Natural rock columns often assume strange geometries that look unstable under the static loading of the rock mass itself and even more so under the resonance inducing, dynamic loads of seismic shaking. A two-dimensional finite element stress model was applied to the analysis of six selected rock columns formed in welded, horizontally jointed tuff in the Chiricahua Mountains, Arizona. In none of the cases did the stress modelling indicate proximity to either compressional or tensile failure. The modelling revealed that failure because of slip along inclined joints penetrating the rock was much more likely. The uniformity of column heights suggests that either rare, high velocity winds or prehistoric seismicity cropped the previous generation of columns. An estimate of the resonant frequencies of a typical column provides some idea of the dynamic response of the columns to seismic shaking. (from Author) 967082 Fitting the profile B. Clarke, M. Gambin Br J. Powell, Ground Engineering, 29(2), 1996, pp 17-20. The interpretation of the design specific Menard pressuremeter test evolved from the theoretical study of expansion of cylindrical cavity modified by experience. The method produces design parameters E,,, the pressuremeter modulus and PI,,,, the Menard limit pressure. The limit pressure is defined as the pressure required to double the cavity volume, the pressuremeter modulus is a soil stiffness derived from the initial quasielastic response of the ground. The latter has been based on identifying the extent of the minimum rate of expansion of the membrane. Jezequel (1995) has proposed a modification to this. The minimum value of the change in volume with respect to applied pressure is selected and the volume at the point is identified as V,. The data from the ground response curve which have values of change in volume with respect to applied pressure that fall within 120% of that point are used to calculate the pressure meter modulus. (from Authors) 967083 The definition of yield for bonded materials V. Malandraki & D. 6. Toll, Geotechnical & Geological Engineering, 14(l), 1996, pp 67-82. In this paper the different definitions of yield for bonded materials are reviewed. It is suggested that yield should be defined based on changes in stiffness from the tangential stiffness versus axial strain graph. The first yield mode is defined when shearing at low confining stresses and the bonded material’s strength is greater than that of the destructured soil. A second mode is defined when shearing at high confining stresses where its strength is unaffected by the bonds. In this paper a new transitional mode of failure is clarified at intermediate stresses. (from Authors)

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967084 Finite element method for ~~ad~e~t ~~~s~~ci~~ at large strains Xikui Li & S. Cescotto, International Journal for Numerical Methods in Engineering, 39(4), 1996, pp 619-633.

A finite element method for gradient elasto~plastic continuum in which the yield strength of strain hardeni~g/softening materials not only depends on the effective plastic strain but also on its Laplacian is presented. The consistent integration algorithm to update the stress and the internal state variable at integration points and the consistent compliance matrix for the gradient plasticity arc formulate in the non-local sense. (from Authors) 967085 Deformations due to gravity In ran elastic soil mediwm part 1. Uni-axial strain state J. Przewlocki, Archives of Hydroengineering & Environmental Mechanics, 41(3-4), 1994, pp 53-74. The random elasticity theory is applied to the statistically homogeneous soil layer subjected to its own weight. The modulus of elasticity is assumed to be a stochastic process and the uni-axial strain state is considered. The governing elasticity equations are presented in altc~at~v~ ways, as a first order stochastic differential equation either with a random coefficient or random forcing function and as a second order stochastic differential equation. The solution is obtained by the approximated analytical methods i.e. perturbation procedure and Adomian’s decomposition method. In a framework of this method the analytical expression defining the displacement as a stochastic process is presented. (frrom Author) 967086 Deformations due to gravity in ran elastic soil medium part 2. Plane strain analysis J. Przewlocki, Archives of Hydroe~gi~ee~i~g Mechanics, 41(3-4), 1994, pp 75-98. The random elasticity theory is applied to statistically homogeneous elastic soil half-plane subjected to gravity. The analysis is performed for the half-space plane strain state. Only the elastic modulus is con to be uncertain and is treated as a two-dimensional field. On the basis of Green’s function approach, the stochastic partial differential equations gove~~8 the problem, are converted into stochastic integral equations. Then the perturbation procedure and Adomian’s decomposition method are applied. The method is essentially the solution of the stochastic Volterra equation by the ~e~rna~o series expansion. (from Author) 967087 Uniaxial compressive strength and coast Ioad strength of rocks K. T. Chau & R. II. 6. Wong, ~nterna~io~~~Journal of Rock Mechanics & Mining Sciences, 33(2), 1996, p Examines the applicability of the Broc~-Franklin formula to Hong Kong rocks and to study analytically the conversion factor K relating Ce (uniaxial compressive strength) to Zs(sO) (point load strength). Note that for axial point load tests Z+c) varies with both the size and shape of the specimen. Consequently, diametral point load nerally more preferable to the axial point load test. for the sake t load test is of mathematical simplicity, only the considered in this study. (from Auth 967088 Dynamic shear strength of rock Joints so loading M. Barbero, G. Barla & A. Zaninetti, ~~ie~atia~a~ Journal of Rock Mechanics & Mining Sciences, 33(2), 1996, pp 141151. Following the description of novel shear eq~~ment which allows the shear tests to be carried out under both static and dynamic loading conditions, the results of tests on saw-cut surfaces are given, It is shown that: und.er low normal stress