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Deep-seated landslides in slopes are often induced by rainfall due to pre-existing cracks or weak layers. A series of centrifuge model tests under rainfall conditions were conducted on slopes with different types of cracks. The histories of suction and displacement of the slope were measured during the tests to investigate the infiltration–deformation–failure process of the slopes. The wetting front curved notably near the crack under rainfall conditions. The deformation of the slope was mainly caused by the saturation of soil and crack-affected water infiltration under rainfall conditions. The displacement process of the slopes with cracks can be divided into a small displacement stage, a rapid increase stage, and a stable stage.

1. Tension Crack In Cohesive Soil Test

The influence of the crack on the infiltration and deformation of the slope decreased with increasing distance from the crack. Rainfall induced significant vertical deformation near the vertical crack rather than horizontal deformation. In contrast to the oblique crack, the vertical crack on the slope top was unlikely to lead to global landslide under rainfall conditions.

The deformation–failure behavior of the slope with cracks was also affected by the rainfall style and rain intensity. Previous article in issue. Next article in issue.

1,2,3, 2, 2 and 21State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China2Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing 210024, China3College of Resource, Hebei University of Engineering, Hebei University, Handan 056038, ChinaReceived 18 November 2013; Accepted 16 December 2013; Published 4 March 2014Academic Editors: C. Petrone and G. AbstractThe crack developing depth is a key problem to slope stability of the expansive soil and its project governance and the crack appears under the roles of dry-wet cycle and gradually develops. It is believed from the analysis that, because of its own cohesion, the expansive soil will have a certain amount of deformation under pulling stress but without cracks. The soil body will crack only when the deformation exceeds the ultimate tensile strain that causes cracks. And it is also believed that, due to the combined effect of various environmental factors, particularly changes of the internal water content, the inherent basic physical properties of expansive soil are weakened, and irreversible cumulative damages are eventually formed, resulting in the development of expansive soil cracks in depth. Starting from the perspective of volumetric strain that is caused by water loss, considering the influences of water loss rate and dry-wet cycle on crack developing depth, the crack developing depth calculation model which considers the water loss rate and the cumulative damages is established.

Tension Crack In Cohesive Soil Test

Both the proposal of water loss rate and the application of cumulative damage theory to the expansive soil crack development problems try to avoid difficulties in matrix suction measurement, which will surely play a good role in promoting and improving the research of unsaturated expansive soil.