Zonal disintegration phenomenon based on triaxial dynamic load test of hollow cylindrical sandstone specimens

In the process of deep roadway excavation, the zonal disintegration phenomenon of surrounding rocks has attracted a lot of attention from rock mechanics. There are relatively few studies on zonal disintegration of rock specimens in laboratory experiments. In this paper, a split Hopkinson pressure bar device was used to perform compression tests on hollow cylindrical sandstone specimens under different confining pressures. The failure specimen shows zonal disintegration. According to the theoretical analysis of elastic-plastic mechanics, it is found that there is a maximum tensile strain at the elastic-plastic boundary, which leads to annular cracks in the radial direction and the formation of zonal fractures. In the plastic zone of the specimen, there is a large tensile strain near the hole. As a result, it is prone to spalling near the hole. In the elastic zone of the specimen, as the radius increases, the hoop strain is converted from compressive strain to tensile strain, resulting in tensile cracks on the outside of the specimen. The phenomenon was also simulated using ABAQUS. The simulation results are basically consistent with the experiments and can intuitively explain the spalling around the hole and the damage to the specimen.

Automated summary

This paper investigates the zonal disintegration phenomenon of surrounding rocks in deep roadway excavation. Experimental and theoretical analysis show that there is a maximum tensile strain at the elastic-plastic boundary, leading to the formation of annular cracks and zonal fractures. ABAQUS simulation results are consistent with the experiments and provide an intuitive explanation for the spalling and damage to the specimen.