Rock mechanics in the 1990s: rock mechanics of building stones and quarries

Rock mechanics in the 1990s: rock mechanics of building stones and quarries

PROPERTIES:DEFORMATION & STRENGTH Coal Measures are highly laminated, and slippage along their bedding planes frequently occurs if bent en masse. The ...

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PROPERTIES:DEFORMATION & STRENGTH Coal Measures are highly laminated, and slippage along their bedding planes frequently occurs if bent en masse. The stronger rocks have well developed joint patterns, while the softer rocks readily exhibit fiowage. Around the openings, zones of yielded rock are often present. No satisfactory analytical solution has so far been developed for this very comp.lex condition, but nevertheless it has been possible to build up the hypotheses given in this chapter to indicate the likely behavior of the strata in various given situations. -from Author 943099 A rheological model of a fractured solid V. Lyakhovsky, Yu. Podladchikov & A. Poliakov, Tectonophysics, 226(1-4), 1993, pp 187-198. Experiments to study the behavior of various materials point to the relation that exists between elastic properties and the type of stress. The influence of the state o f stress on the elasticity of a fractured material is discussed for a physically non-linear model of an elastic solid. The straindependent moduli model of material, presented in this paper, makes it possible to describe this feature of a solid. It also permits to simulate a dilatancy of rocks. A damage arameter allows description of a rheulogical transition om the ductile regime to the brittle one, and simulation of the rock's memory, narrow fracture zone creation and strain rate localization. Additionally, the model enables the investigation of the final geometry of fracture zones, and also to simulate their creation process, taking into account pre-existing fracture zones. -from Authors 943100 Correlation between point load index and compressive strength for quartzite rocks V . K . Singh & D. P. Singh, Geotechnical & Geological Engineering, 11(4), 1993, pp 269-272. The relationships of the point load test with uniaxial compressive strength was examined using quartzite rocks to substantiate the existing correlations -Authors 943101 Rock mechanics in the 1990s: rock mechanics of building stones and quarries ed B. C. Haimson, International Journal of Rock Mechanics and Mining Sciences, 30(7), 1993, pp 1527-1573. These papers were originally presented at the 34th US Symposmm on Rock Mechanics, June 1993. The 8 parers include: rock property variation within a quarry; stability of Pharaohs underground cavern and Sphinx deterioration; cracks in building stone; curtain wall design; and structural analysis of stone clad precast concrete building panels. -R.Gower 943102 Scanning electron microscope and acoustic emission studies of itacolumites H. Suzuki, T. Yokoyama & M. Nishihara, Journal Geological Society of Japan, 99(6), 1993, pp 443-456. The fabric of itacolumite, or flexible quartzite, was studied in detail under SEM, and the existence of narrow uniform intergranular void spaces between interlocked quartz grains was ascertained. The void spaces are interconnected with each other and extend three-dimensionally throughout the rock mass. For clarifying the mechanical behavior of itacolumite, slab specimens of itacolumites were deformed and ruptured in the simple bending test, and acoustic emission (AE) signals were recorded and analyzed. The results obtained by SEM and AE studies suggest that the fabric and deformation.process of itacolumite are schematically represented by a jigsaw puzzle model. -from Authors 943103 Stress-history-based model for G* of cohesionless soils R . D . Hryciw & T. G. Thomann, Journal of Geotechnical Engineering - ASCE, 119(7), 1993, pp 1073-1093. A empirical, stress-history - based model for the small strain (or elastic) shear modulus G" of cohesionless soils has been developed. While previous efforts have found G" scaling with approximately the ~ power of confining stress (n = 0.5), the present work shows n on virgin loading n t ranging from 0.39 to 0.7'2. Furthermore, nI was shown to be related to the maximum dimensionless stiffness coefficient for 1-D strain (S~wm..). The values of n on unloading and reloading n, disp~layea a much narrower range than n r The

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developed model for G" includes overconsolidation ratio (OCR) terms for the horizontal and vertical directions. -from Authors 943104 Anisotropic three-dimensional behavior of a normally consolidated clay M . M . Kirkgard & P. V. Lade, Canadian Geotechnical Journal, 30(5), 1993, pp 848-858. An experimental study is presented of the influence of the intermediate principal stress on the stress-strain, pore-pressure, and strength characteristics of a normally consolidated, natural anisotropic clay, San Francisco Bay Mud, under undrained conditions. Consolidated undrained triaxial compression tests and triaxial tests with independent control of all three principal stresses on cubical specimens were performed. The stress-strain behavior and the porereSsure characteristics as well as the effective stress [lure surface can be described as being cross-anisotropic. -Authors 943105 Dynamic stiffness of unbounded medium based on damping-solvent extraction Chongmin Song & J. P. Wolf, Earthquake Engineering & Structural Dynamics, 23(2), 1994, pp 169-181. In the dam~ing-solvent extraction method, to calculate the dynamic-stiffness matrix of an unbounded medium, a finite region of the medium, adjacent to the structure is analysed in the first step., whereby hysteretic material damping is introduced artificially as a solvent. This leads to the dynamic-stiffness matrix of the damped bounded medium, which is assumed in the second step to be equal to that of the damped unbounded medium. I n the third step, the effect of the material damping on the dynamic-stiffness matrix is eliminated. The method is evaluated thoroughly for dynamic soil-structure interaction and for seismic reservoir-dam interaction using stringent simple cases with analytical solutions available and is also applied to practical examples. -from Authors 943106 Fuzzy finite element analysis of a foundation on an elastic soil medium S. Valliappan & T. D. Pham, International Journal for Numerical & Analytical Methods in Geomechanics, 17(11), 1993, pp 771-789. One of the important factors that lead to errors in settlement predictions is the degree of precision in obtaining the soft parameters. In this paper, a model based on the theory of fuzzy sets is presented to take account of the uncertainty in the soil behaviour. This proposed method considers the .elastic modulus and Poisson's ratio as two fuzzy numbers m the elastic matrix. By means of a fuzzy inference scheme, the total possibility distributions or total membership functions of the finite element results may be obtained by considering the estimated error resulting from the mesh dxscretization. -from Authors 943107 Elimination of m e m b r a n e compliance in undrained triaxial testing. I. Measurement and evaluation P . G . Nicholson, R. B. Seed & H. A. Anwar, Canadian Geotechnical Journal, 30(5), 1993, pp 727-738. Several alternative approaches have been suggested for evaluation and correction of the testing errors caused by membrane compliance. The degree to which membrane compliance may affect the results of an undrained test is a function of the soil grain size and overall geometry of the test specimen, as well as specimen density and range of effective confining stresses during a gxven test. The scope of this paper is threefold: firstly, to review, examine, and evaluate the variety of methods to measure and characterize membrane compliance; secondly, to develop an improved understanding of the factors affecting membrane compliance; and thirdly, to provide an enhanced, updated, and expanded correlation for estimating membrane compliance characteristics as a function of material grain size for a range of soil types. -~rom Authors