Filtration anisotropy of swelling foundation soils and slopes

124A 893139 Random walk method to simulate pollutant transport in alluvial aquifers or fractured rocks Ackerer, P Proc NA TO Advanced Research Workshop on Advances in Analytical and Numerical Groundwater Flow and Quality ModeUing, Lisbon, 2-6 June 1987 P475-486. Publ Dordrecht: Reidel. 1987 The theory of the three dimensional random walk model for simulating groundwater contamination is presented, and its results compared with those from an analytical solution and the three dimensional finite difference method. The random walk method is then applied to special cases of contaminant migration in a stratified aquifer and a fractured porous medium. Comparisons are also made between experimental data and predictions of the random walk model and analytical solution for the case of a single fracture. 893140 Filtration anisotropy of swelling foundation soils and slopes Sobolevsky, Y A; Morgachiev, V N Proe 6th International Conference on Expansive Soils, New Delhi, i-4 Dec 1987 P177-182. Publ Rotterdam: A A Balkema, 1988 Naturally fissured dry swelling soils show permeability anisotropy with vertical permeability prevailing, but on wetting the permeability will change to isotropic then horizontal prevailing. The reverse happens on dehydration. An analysis of pattern of seepage flow and seepage forces beneath a foundation and in a slope of expansive soil under the three different permeability states is presented. 893141 Measurement of solute suction in high plasticity clays Schreiner, H D Proc Ninth Regional Conference for Africa on Soil Mechanics and Foundation Engineering, Lagos, September 1987 V I, PI63-171. Puhl Rotterdam: A A Balkema. 1987 Reliable measurement of solute suction has proved difficult in the past. A salt distribution model of the soil water system which should be of benefit in the understanding of the role of salts in the soil water is presented. The model uses a two-phase description of the soil water in which the dissolved salts are found in only one of the phases. Some inconsistencies observed by other authors are explained using the model. Auth.

Compressibility, swelling and consolidation

893 ! 43 Determination of consolidation properties for very soft clay Tan, S A: Tan, T S; Ting, L C: Yong. L C; Karunaratne. K Y; Lee, S L Geotech Test J Vll. .V4. Dee 1988, P233-240 A finite strain consolidation test with a constant surcharge to determine compressibility and permeability of a very soft clay is proposed. The method uses gamma rays and pore pressure transducers to measure density and pore pressure profiles at various times of the test without hindering the consolidation process. The profiles are then used to determine compressibility and permeability of the soft clay. A test is carried out to determine these properties, which are used in a finite strain consolidation theory to predict the settlement, void ratio and pore pressure distribution of the other tests performed under different initial and boundary conditions. Predictions agree well with experimental data.

893144 Finite strain consolidation - a study of convection Tan, T S; Scott, R F Soils Found V28. N3. Sept 1988, P64-74 Finite strain consolidation of a 2 phase soil medium is approached using a Eulerian formulation. Simple governing equations are developed which can be straightforwardly transformed to a Lagrangian framework for the one-dimensional case. The importance of the convective term involving the solid phase viscosity is examined. A numerical analysis including this term is suggested and its suitability verified by the finite difference method for the one dimensional case. This approach is also applicable to multidimensional problems.

893145 Consolidation of multilayered anisotropic soils by vertical drains with well resistance Onoue, A Soils Found 1/28, N3, Sept 1988, P75-90 Taking well resistance into account, a numerical analysis method is presented to solve the consolidation problem in multilayered anisotropic clayey subsoil with vertical drains. Analytical values correlate with results from 2 in situ consolidation tests. A new procedure is then proposed to predict consolidation degree of multilayered ground using existing equations concerning single-layered centripetal consolidation. Results obtained compare favourably with numerical results.

See also: 893230, 893328 893142 Removal of cementation bonds in stressed overconsolidated clays Griffiths, F J'. Joshi. R C; Nagaraj, T S Geoteeh Test J VII, N4, Dec 1988. P227-232

893146 Study on the settlement of saturated clay layer induced by cyclic shear Ohara, S; Matsuda, H Soils Found V28, N3, Sept 1988, P103-113

Compressive response of stiff cemented clays subject to cement removal was studied. I-D consolidation tests were performed with and without EDTA flushing to remove cementation. Results show that removal of the cementation bonds can cause an increase in soil volume, and void ratio increases to the level of equilibrium for the uncemented state, attributed to latent physico-chemical behaviour of the clay, restrained by the normal consolidation process.

Cyclic simple shear tests were conducted on normally consolidated and overconsolidated kaolinite clay. Afterwards, excess pore pressure was dissipated and settlement measured to estimate seismic settlement of the clayey layer. Results show that excess pore pressure induced is dependent on the amplitude of shear strain, number of cycles and overconsolidation ratio. Also, seismic settlement depends on excess pore pressure accumulated during cyclic shear and overconsolidation ratio.

1989 Pergamon Press plc. Reproduction not permitted