Numerical Modeling of Soils Subjected to Drying Climate Effects
Abstract
This contribution presents laboratory tests conducted to investigate the influence of soil structure, soil-interfaces, and the initial saturation on the cracking and shearing behavior of a high expansive soil mixture consisted of 75% of kaolin and 25% bentonite. Specimens were made up following different preparation methods (e.g. involving different compaction methods, different initial water contents, and initial dry densities) leading to different types of soil structures. Two different series of experimental tests were performed involving desiccation and direct shear interface tests. Samples fully and partially saturated were subjected to drying and shearing to understand better the effect of soil moisture on crack patterns and soil strength. Furthermore, free and constrained desiccation tests were conducted to investigate crack formation of fully-saturated (slurries) and compacted specimens during the first drying/wetting process by using smooth and circular-spiral grooved interfaces, respectively. As for the direct shear interface tests, including soil-plate interfaces with four different textures, namely: circular grooves; smooth plate; grooves perpendicular and parallel respect to the shearing direction. Desiccation results revealed that the free specimens (smooth interface) experienced free shrinkage without cracks whereas the cracks developed in the constrained ones. It was found that the shear strength of the soil is strongly corresponded to the saturated condition and shear direction (i.e. texture interface direction). In general, the unsaturated specimens experienced much higher shear-interface strengths compared to those of saturated ones. This can be mainly attributed to the significant contribution of the matric suction to the shearing behavior of soil. It is apparent that the hydro-mechanical behavior of a soil can be predicted based on key significant factors, such as, soil structure, soil- interface, and the initial saturation condition.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP11D2118S
- Keywords:
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- 3909 Elasticity and anelasticity;
- MINERAL PHYSICS