Experimental study on soil-water characteristic curve for silty clay with desiccation cracks: Fid-Bau Portal

Experimental study on soil-water characteristic curve for silty clay with desiccation cracks

Li, J.H. / Lu, Z. / Guo, L.B. / Zhang, L.M.

AbstractCracks are ubiquitous in soils and can provide preferential pathways for rainfall infiltration and contaminant transport. The soil-water characteristic curve (SWCC) for a cracked soil is required when conducting seepage analysis. However, measuring SWCCs for cracked soils is difficult due to two reasons: (1) The presence of cracks leads to a significant change in the water content at extremely low suctions that cannot be controlled accurately; (2) The full development of cracks generally requires a large apparatus to accommodate the representative elementary volume of a crack network. This study aims to develop an experimental method to measure the SWCC for a silty clay with desiccation cracks. A large apparatus, 350mm in diameter and 280mm in height, was developed, which is capable of controlling extremely low suctions (<0.01kPa) at an accuracy of 0.005kPa and accommodating a clay sample with fully developed crack networks. The crack development in the soil sample was observed, providing necessary parameters for the prediction of SWCCs based on a theoretical model for cracked soils. The drying and wetting SWCCs for a silty clay with desiccation cracks were measured in the suction range from 0.01kPa to 300kPa, and compared with the SWCCs predicted using the theoretical model.

Highlights•An experimental method was developed to investigate the soil-water characteristic curve (SWCC) of a cracked clay.•The newly designed apparatus can accommodate a large cracked soil and control the extremely low suctions accurately.•The SWCCs of a cracked soil during drying process and wetting process were measured.•The crack development during tests was recorded and used in a theoretical model to predict the hysteresis SWCC.