Basic properties of loam soils in Amori prefecture, Japan

68A 942056 Reversal shear box test for Hong Kong saprolitic soils. Technical note Au, S W C Q J Engng Geoi V26, N3, 1993, P233-237 Drained direct shear tests (shear box tests) have recently become accepted for estimation of strength parameters of saprolitic soils for slope design in Hong Kong. These materials are highly variable and considerable effort is required to select a representative range of samples if the ordinary shear box test is employed. The use of the reversal shear box test on a single sample is proposed to overcome this drawback. Lower limit strength parameters are obtained for use in routine slope stability analysis. 942057 Study of rock joints under cyclic loading conditions Jing, L; Stephansson, O; Nordlund, E Rock Mech Rock Engng V26, N3, July-Sept 1993, P215-232 A conceptual model for behaviour of rock joints during cyclic shear and under constant normal stress has been developed on the basis of shear tests on 50 replica joints in concrete. Shear strength and deformability were found to be anisotropic and stress dependent. A two dimensional constitutive model for joints is formulated within the framework of non-associated plasticity. When implemented within the UDEC numerical code, this model gives predictions in good agreement with some well known test results. 942058 Effect of setting method on the behaviour of clays in triaxial compression from saturation to undrained shear Ampadu, S K; Tatsuoka, F Soils Found V33, N2, June 1993, P14-34 The conventional (wet) method of preparing saturated clay specimens uses saturated porous stones, wet filter paper, and full drainage lines. The specimen takes up water and swells, which can affect subsequent behaviour. It is shown that these effects can be reduced by using the dry setting method (dry porous stones and filter paper, effective pressure applied before allowing contact with free water). Response of in situ clay and reconstituted kaolin prepared by these two methods is compared over the whole stress range from saturation to failure. Consolidation to higher stresses may erase these setting effects. 942059 Basic properties of loam soils in Amori prefecture, Japan Moroto, N Soils Found V33, N2, June 1993, P35-46 Geotechnical characteristics have been evaluated for ten volcanic cohesive (fall loam) soils, two secondary sedimented loam soils, and two alluvial soils from Amori prefecture. Physical and chemical properties and their interrelations are described. CBR tests on undisturbed and compacted fall loams are considered in detail. The importance of liquidity index when designing earthworks in these soils is discussed and a useful engineering classification chart is presented. 942060 Quality of the lubrication layer used in element tests on granular materials Goto, S; Park, C S; Tatsuoka, F; Molenkamp, F Soils Found V33, N2, June 1993, P47-59 Cyclic, displacement controlled direct shear tests were carried out under controlled vertical loads on Toyoura (fine, subangular) and Leighton Buzzard (coarse, subround) sands and Hime

gravel. Four types of lubrication layer, various arrangements of rubber membranes and silicone grease, were used to minimise friction and end effects. Relative performances are discussed. For the gravel and coarse sand it was necessary to add fly ash powder to the grease to prevent squeezing out at points of stress concentration. 942061 Imperfection sensitivity for size effect of granular materials Ikeda, K; Goto, S Soils Found V33, N2, June 1993, P157-170 The size effect of granular test specimens in triaxial compression is first explained using bifurcation theory, with emphasis on the role of initial imperfections. The analogy with imperfection-sensitive behaviour of shell structures is examined and it is proposed that the influence of initial imperfections for sand specimens decreases inversely proportional to their height. Power laws for imperfection sensitivity are derived, which allow construction of the idealised stress ratio vs strain curve for an infinitely high specimen. This method has successfully categorised bifurcation behaviour of dense and loose sand. 942062 Identification of the deformability of an arch dam foundation Castro, A T; Lemos, J V; Pina, C A; Silva, H S Proc EUROCK'93, Lisbon, 21-24 June 1993 VI, P37-43. Publ Rotterdam: A A Balkema, 1993 The Funcho Dam in Portugal is a double arch dam with concrete foundations resting on a schist and greywacke rock mass showing large changes in deformability between the two banks. During construction, vertical displacements of the foundation were measured. Using this information, back analysis was used to compute the average deformability of each zone of the dam foundation. Finite element modelling is used to simulate behaviour of the structure. 942063 Joint patterns and anisotropic rock mass deformational behaviour Crosta, G Proc EUROCK'93, Lisbon, 21-24 June 1993 V1, P63-70. Publ Rotterdam: A A Balkema, 1993 The widely observed anisotropy of rock masses is strongly influenced by the orientation and properties of their joints. The distinct element method is used to examine effect of orientation of joints with respect to loading direction on the deformational behaviour of rock blocks. Results indicate elastic modulus can be reduced up to 50 times simply by changing the relative joint orientation. Implications to adequate characterisation of jointed rock masses are considered. 942064 Self-adaptive timestep control for the vlscoplastic-viscoelastic analysis in finite elements of the hydromechanical coupling in fractured rock masses Duarte, I C; Vaz, L E; Vargas, E. Proc EUROCK'93, Lisbon, 21-24 June 1993 VI. P97-105. Publ Rotterdam: A A Balkema, 1993 Development of an efficient finite element analysis method for hydromechanical coupling in jointed rocks is discussed. Mechanical behaviour as an equivalent continuum is described using the multilaminar concept. The viscoelastic-viscoplastic model is used to represent the Barton-Bandis constitutive model for joint behaviour. It is necessary to establish suitable values for the time steps in order to ensure a stable, convergent, and precise solution. The program under development