Centrifugal and field studies on water infiltration characteristics below canals under wetting-drying-freezing-thawing cycles

Abstract

Seepage is one of the main causes for the deformation and instability of canal slopes in Xinjiang, China. In this study, centrifugal model tests under wetting-drying (WD) and wetting-drying-freezing-thawing (WDFT) cycles were performed to investigate the water infiltration characteristics below a canal. The results show that the shallow soil of the canal models was fully saturated in the wetting process. Compared with the canal model under the WD cycles, the canal model under the WDFT cycles had larger saturated areas and a higher degree of saturation below the canal top after each cycle, indicating that the freezing-thawing (FT) process in the WDFT cycles promoted the water infiltration behavior below the canal slope. The cracks on the surface of the canal model under the cyclic action of WDFT developed further and had a higher connectivity, which provided the conditions for slope instability from a transverse tensile crack running through the canal top. On this basis, a field test was conducted to understand the water infiltration distribution below a typical canal in Xinjiang, China, which also verified the accuracy of the centrifugal results. This study provides a preliminary basis for the maintenance and seepage treatment of canals in Xinjiang, China.