The mechanism of soil failures along cracks subjected to water infiltration

A field irrigation test was conducted at a crack-developed loess slope in Heifangtai, China, to study the slope instability that was caused by water infiltration. In the field test, the formation of sinkholes was considered a major type of soil failure. To investigate the mechanism of soil failures along cracks caused by water infiltration, a mechanical-hydraulic coupled analysis was conducted using a finite difference program. A moving boundary algorithm was proposed and adopted in the numerical model. Different draining rates of water in the crack were studied. The failure mechanism was identified as: the wetting-induced loss in shear strength of the soil, and the rapid loss of lateral support provided by the water during the dropping stage of water level. Under such conditions, a sinkhole is likely to form in the field.