Function of a Deep-Buried Isolated Trench and Its Effect on Cracking Failure Characteristics of a Slope under Artificial Rainfall

When tests are conducted on the field slope under artificial rainfall, because artificial rainfall is often limited to implementation in the mode of local rainfall, there is a boundary constraint effect between the rainfall area and the non-rainfall area, which is manifested in the lateral infiltration of rainwater and the slope deformation retardation of non-rainfall area to the rainfall area. Firstly, a deep-buried isolated trench was proposed to solve these boundary constraints. Then, field cracking tests and the corresponding numerical simulation were conducted under rainfall. In the end, the response of water content and the cracking failure characteristics of the slope were analyzed during rainfall, and the effect of a deep-buried isolated trench on the cracking characteristics of the slope was evaluated. The results indicate that the proposed deep-buried isolated trench measure can effectively eliminate the deformation retardation resulting from the adjacent non-rainfall area so a through-crack parallel to the slope shoulder that extended on both sides of the boundary of the rainfall slope was observed at the slope crest and a cracking failure in the shape of the overall downward cutting was realized. As the crack occurred, the rainwater infiltration further aggravated expansion of depthwise cracks, and a local sliding zone was formed in the upper part of the slope. The deep-buried isolated trench solves the boundary constraints, such as lateral infiltration of rainwater and deformation retardation, and can provide an effective technical measure for the field slope test under artificial rainfall.