engleski

The relationship between swelling and shear strength properties of bentonites

Clay Geosynthetic Barriers are manufactured hydraulic barriers. The mineral component usually consists of bentonite, which belongs to a group of expansive soils. The aim of this study was to establish the influence of swelling on mechanical properties of bentonites. For this purpose, granular bentonite Volclay was chosen for laboratory testing. Its mineralogical composition was predominantly montmorillonite (80% - 85% by mass). The correlation between swelling and water content on one side and changes in shear strength i.e. shear strength parameters on the other were tested using a direct shear device. During several series of testing, different levels of swelling ofbentonite were simulated under the conditions of changing normal stress and hydration times. Swelling behaviour of bentonite was determined through the long-term swelling tests using oedometer, under changing normal stress. Shear strength testing show decreasing cohesion with longer hydration of bentonite. The friction angle increases with hydration that lasts from 7 to 14 days. There is no significant change in the friction angle with hydration time longer than 14 days.

Bentonite ; Swelling ; Direct shear test ; Shear strength

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