EXPERIMENTAL STUDY ON PHYSICAL MODEL OF GROUND FISSURES ERODED BY SURFACE WATER

Surface water infiltration erosion is a crucial factor in the exposure of ground fissures to the surface. Due to its unique tectonic environment, rainfall-eroded ground fissures are highly developed in the Kenya Rift Valley. In this paper, we use the ground fissures in the Kenya Rift Valley in East Africa as a model to establish a geological model for the rupture and expansion of buried rock and soil under the conditions of rainfall erosion. Through physical model testing, the evolutionary pattern of hydraulic erosion failure in the soil during the development of ground fissures is revealed. The test results show that: (1)the fracture propagation process of surface water-eroded ground fissures can be divided into three stages: uniform infiltration stage, erosion hollowing stage, and collapse disaster stage. (2)The influential area of concealed rock and soil fractures is the dominant channel of surface water infiltration, and hydraulic erosion in this area is intense. (3)When erosion collapse is formed, the internal water content and pore water pressure of the soil change synchronously. The abrupt change of water content in the soil reflects the development of cracks and the formation of local collapse, revealing the process of erosion collapse in the soil. The physical model test based on surface water infiltration can provide scientific theoretical support for the monitoring and prevention of ground fissures.