Laboratory and centrifugal model tests on failure mechanism of canal slopes under cyclic action of wetting–drying

Abstract

Cyclic action of wetting–drying (WD) is a main cause for the deterioration and failure of expansive soil canals. This paper presents details of an investigation dealing with the influences of WD cycles on the deterioration characteristics and failure modes of the canals in Xinjiang, China by laboratory and centrifugal model tests. The results show that the strength parameters of expansive soil have a significant reduction with the crack development in the cyclic WD processes. The final attenuation ranges of cohesion and internal friction angle are about 53%, 46% and 37%, 28%, respectively. Additionally, in the centrifugal model tests, the crack development of the canal model starts around the water level line and then the canal model appears a disintegration and spalling area below the water level line under cyclic action of WD. The failure mode of this expansive soil canal can be regarded as a type of failure due to the disintegration and spalling of shallow soil.