Prediction of cyclic undrained strength of sand subjected to irregular loadings

l 3A 871095 Prediction of cyclic undrained strength of sand subjected to irregular Ioadings Tatsuoka, F: Maeda, S: Ochi, K: Fujii. S Soils Found ~26, :V2. J:ale 19~6. P73-90 Cyclic undrained stress strain behaviour of sands under uniform and irregular (earthquake) loading was studied at a range of densities, using torsional shear tests on hollow cylindrical specimens. A new method to account for the differences in liquefaction strength between uniform and irregular loading is proposed. The concept of cumulative damage is studied, and found to be useful to predict whether a given sand element will fail. knowing the time history of the irregular loading and the strength curve for normal loading. 871096 Stability of soil masses in random seismic environment Rahman, M S Proc 5th Engineering Mechanics Division Speciali o' Conference. Wyoming, 1-3 Aug 1984 V2, P1241-1244. Publ New York: ASCE. 196'4 Earthquake motions are treated as a random process and simple methods are developed for predicting damage in soil masses associated with (1) progressive build up of pore pressure (loose to medium dense sandy soils) and (2) accumulations of displacements along a yield surface (compacted clays and dense sands). The soil mass is treated as a linear viscoelastic system, and response is assumed to be caused primarily by vertical propagation of shear waves from the underlying formation. The cases of a soil deposit supporting a structure, and an earth dam or embankment are analysed. 871097 Dynamic analysis of level ground by an elastic-plastic constitutive model Hirai, H; Satake, M Proc 5th International Conference on Numerical Methods in Geomechanics, Nagoya, 1-5 April 1985 VI, P365-372. Publ Rotterdam. ,4. A. Balkema, 1985 An elastic-plastic constitutive model is proposed which is capable of describing the cyclic behaviour of sands reasonably accurately. The numerical formulation and solution techniques are presented to analyze the dynamic behaviour of sand deposits subjected to earthquake shocks. It was shown that the permeability coefficient can significantly influence the response of the ground during earthquakes. 871098 Constitutive model of soils for estimating liquefaction resistances Matsuoka, H: Yamazaki, H; Koyama, H Proe 5th International Conference on Numerical Alethods in Geomechanics, Nagoya. 1-5 April 1985 V1, P381-388. Publ Rotterdam: A. A. Balkema, 1985

871099 Effective stress response analysis for level sand deposits with cyclic mobility Nishi, K: Tohma, J: Kanatani, NI Proc 5th International Conference on Numerical Methods in Geomechanics, .\'agoya, 1-5 April I985 VI, P389-397. Publ Rotterdam: ,4. ,4. Balke,za. i985 The numerical analytical method based on effecti,,e stress was developed to estimate the response and the settlement of a level saturated sand deposit in earthquake motion. The constitutive relations adopted make it possible to evaluate the deformation properties of sand over a wide range of densities. The numerical stud', was conducted and the analytical results compared with experimental results for the behaviour of saturated model sand deposits in shaking table tests.

871100 Numerical model for liquefaction problem under multidirectional shearing on horizontal plane Yamazaki, F: Towhata. I; Ishihara, K Proc 5th International Conference on Numerical Methods in Geomechanics, Nagoya, 1-5 April 1985 V1, P399-406. Publ Rotterdam: .4. ,4. Balkema, 1985 A new effective stress model is developed for computing liquefaction potential of soil elements under multi-directional shearing. This model is composed of both a deformation model with multiple non-linear springs, and a pore pressure model based on the strain energy concept. Using this model, several series of numerical simulations of liquefaction for several loading patterns, such as circular shear pattern, were conducted. Numerical results obtained by the model were in good agreement with laboratory test results, in terms of stress-strain relation and pore pressure build-up during shear loading. Furthermore, this effective stress model is incorporated into the theory of wa~e propagation through two-phase media, and dynamic response analysis of horizontally layered ground under n-mlti-directional shaking is made, based on the effective stress method. This analytical procedure was applied to a liquefaction stud?' of a site in Niigata city, devastated by the 1964 earthquake, and coupled effects of two horizontal motions on the dynamic response and liquefaction of the ground were examined.

In Situ Stress

871101 Proceedings of the International Symposium on Rock Stress A constitutive model of soils is proposed, assuming the super- and Rock Stress Measurements, Stockholm, 1-3 September position of strain increments caused by three imaginary two- _ 1986 dimensional slip planes under the respective two principal Stephansson. O (editor) stresses, and considering the mechanism of fabric change due Lulea." Centek. 1986. 694P to cyclic shear stresses. The results of drained true triaxial tests along rotational stress paths on the octahedral plane, the 72 papers are presented in five sections; state of stress in the undrained effective stress paths and the liquefaction resistance earth crust: methods for rock stress measurement; interpretaunder cyclic triaxial compression, and extension conditions are tion of rock stresses: application of rock stress measurements analyzed by the proposed model. A simple method for esti- in mining: and application of rock stress measurements in mating the liquefaction resistance is also proposed, underground construction. (~ 1986 Pergamon Journals Ltd. Reproduction not permitted RMM

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