Abstract-Chemically modified bentonites are being developed with the aim of preserving low hydraulic conductivity in the presence of potentially aggressive permeants in pollutant-containment applications. 'Multiswellable' bentonite (MSB) has been obtained by treating standard sodium bentonite with propylene carbonate. Research on the engineering properties of MSB has focused mainly on permeability and chemical compatibility. Solute diffusion and membrane behavior in MSB have not yet been investigated. A combined chemico-osmotic/diffusion test was performed on a MSB specimen using a 5 mM CaCl 2 solution. Permeability with distilled water and with the 5 mM CaCl 2 solution was measured prior to and after the chemico-osmotic/diffusion tests. The material exhibited time-dependent membrane behavior with a peak osmotic efficiency value (o) of 0.172 that gradually shifted to zero upon breakthrough of calcium ions. Effective diffusion coefficients of calcium and chloride ions were in the range commonly described for untreated bentonite at similar porosities. After the chemico-osmotic/diffusion stage and permeation with 5 mM CaCl 2 , the hydraulic conductivity of MSB increased from 1.1610 À11 m/s to 7.0 610 À11 m/s. The MSB was apparently converted into a calcium-exchanged bentonite at the end of the test. Prehydration and subsequent permeation might have contributed to elution of the organic additive from the clay. Further investigation is recommended to clarify the effect of prehydration on the hydraulic performance of MSB in the presence of potentially aggressive permeants.

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The aim of the paper is to discuss a fully instrumented screw pile load test up to failure, in difficult heterogeneous soil conditions along the shaft. The pre-stressing of the pile during its installation process has been brought to attention as an important item to assisting in explaining the differences in pile capacity and load settlement curve on the one hand, and the data as registered from the pile shaft instrumentation. In the second part of the paper, starting info on the registered load settlement data of the foundation slabs of each of the three, closely positioned, oil tanks of 48 m diameter and 19 m of height are shared and briefly analyzed.