17A 9O1128 Inter layer swemngof Na, Ca-monmmrillonite clays Sivapullaiah, P V Proc 6th International Conference on Expansive Soils, New Delhi, 1-4 December 1987 P423.426. Publ Rotterdam: A A Balkema, 1988
Interlayer swelling of clays has been studied. Hydration isotherms and X-ray diffraction patterns were obtained for NaCa, Na-, and Ca- montmorillonites, black cotton soil and kaolinite. Behaviour of Na-Ca montmorillonite is similar to that of black cotton soil but different from that of homoionic species. All hydrated water in Na-Ca montmoriUonite is interlayer water, and its texture changes with humidity. 901129 Study of anisotropy of swelling in clays Roy, L B; Rao, A S R Proc 6th International Conference on Expansive Soils, New Delhi, 1-4 December 1987 P439-444. Publ Rotterdam: A A Balkema, 1988
Samples of bentonite, kaolin, black cotton, and Tehri Dam soils were compacted to maximum dry density using the standard Proctor Compaction Method. Specimens were then taken at 0, 22.5, 45, 67.5 and 90 deg to the vertical, and swelling and swelling pressure determined using both constant and variable volume methods. Swelling and swelling pressure are seen to be anisotropic, with directional variation of elliptical form with the major axis at 45 deg to the vertical. Montmorillonite was responsible for the swelling. 90113O Effect of anisotropy on swelling and swelling pressure Mukerjee, S; Satyanarayana, B Proc 6th International Conference on Expansive Soils, New Delhi, 1-4 December 1987 P445-450. Publ Rotterdam: A A Balkema. 1988 Samples of a high swelling soil were compacted at conditions corresponding to predetermined points on the standard Proctor and AASHO curves. Variations of swelling, swelling pressure and unconfined compressive strength were studied with respect to angle of sampling and to method of compaction and initial water content. Swelling and swelling pressure vary in an elliptical manner, with major axis at 45 deg to the horizontal. UCS was the same in horizontal and vertical directions, but relatively lower at 45 deg to the horizontal. Static compaction leads to greater swelling than dynamic.
Dynamic properties 901131 Attenuation of ultrasonic waves in rocks (In French) Klimis, N; Massieu, E; Durville, J L Bull Liaison Lab Pones Cbaussees NI61, May-June 1989, P716
P wave attenuation was measured on dry rock samples in the laboratory. Results for about 30 rocks (quartzite, sandstone, limestone, chalk, marble, granite, microgranite, gabbro, laurvickite, basalt, andesite) were interpreted in terms of time and frequency. The coefficient of quality, Q, was estimated by the method of spectral relations. When grain size exceeds about Imm, marked damping due to diffraction becomes evident. Intrinsic attenuation, primarily linked to clay minerals, is also seen. Quantitative interpretation of results is difficult. • M~s 27,,-~
901132 Cohesive soil behavior under random excitation eonditions Aggour, M S; Taha, M R; Tawfiq, K S; Amini, F Geotech Test J VI2, N2, June 1989, P135-142
Resonant column tests were carried out on a cohesive soil at different confining pressures using random torsional and conventional sinusoidal excitation. Damping and shear moduli for random excitation were determined by power density function and transfer function methods, and compared to those from conventional sinusoidal excitation tests. Differences are discussed. Formulae are developed to correct 'conventionally' determined parameters to values more representative of field conditions with random excitement. 901133 Machine foundation - a state of the art Sreekantiah, H R Indian Geotech J vIg, N3, July 1988, P207-225 In design of machine foundations, stability and settlement criteria must consider inertial forces of the machine-foundationsoil system. Laboratory and field methods for determination of dynamic soil parameters are reviewed and factors affecting dynamic parameters discussed. Different methods of analysis of shallow surface and embedded foundations are presented. The importance of stiffness and damping coefficients of the soil and their evaluation are discussed. Test equipment for soils under dynamic loading is described. Finally, the influence of parameters dimensionless mass ratio, dimensionless inertia ratio, eccentric moment and magnitude of moment are discussed. 96 refs. 901134 Shock wave equation of state and finite strain theory Jeanloz, R J Geophys Res V94, NBS, May 1989. P5873-5886 Shock wave methods are used to determine high pressure equations of state and provide information on compressional and thermal behaviour of geological materials at high pressure and temperature, The linear shock velocity-particle velocity equation, known to be successful in describing a wide variety of Hugoniot equation of state measurements, is shown to be virtually indistinguishable from a third order Eulerian finite strain equation of state. Thus shock wave measurements provide strong empirical evidence for the success of the Eulerian approach in describing the compression of condensed matter to high pressures. 901135 Pore pressure buildup and liquefaction failure of anisotropically consolidated sand due to cyclic straining Vasquez-Herrera, A; Dobry, R; Ng, T T Proc Conference on Hydraulic Fill Structures, Fort Collins, 15-18 April 1988 P346-366. Publ New York: ASCE, 1988 ( Geotechnical Special Publication No 21) Hydraulic fill dams and mine tailings, typically composed of loose, saturated silts and sands deposited without compaction, are susceptible to liquefaction flow failure during seismic shaking. A series of cyclic laboratory tests was carried out to verify the influence of several parameters on liquefaction resistance of loose, anisotropically consolidated, contractive silty sand. The tests were strain-controlled cyclic torsional triaxial, which give information on both initial pore pressure buildup and failure after triggering. A simple pore pressure model was developed and fitted to the results, and was capable of predicting excess pore pressure versus number of cycles for this sand at any consolidation stress ratio and cyclic shear strain.
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