Geological Characteristics and Susceptibilty Evaluation of Ground Collapse in Xi'an

With the speed and scale of urban construction in Xi'an city, ground collapse has appeared more and more in people's life. Because of its hidden, sudden and high hazard, it has become one of the main problems threatening urban security. Combined with the drilling and engineering prospection data in the main urban area of Xi'an, According to the stratum distribution in the study area, the formation process and mechanism of ground collapse are comprehensively studied by using the theory of soil arch effect, and the numerical formula between the critical span of ground collapse, the thickness of overlying soil layer and the upper load is established. The susceptibility of ground collapse under different working conditions is obtained through numerical calculation. The results show that the ground collapse accidents in Xi'an are mostly caused by rainwater leakage, pipeline rupture and engineering construction. Under the same geological conditions, the greater the thickness of the overlying soil layer, the greater the limit span of the cavity. Xi'an city is divided into high-medium-and low-prone areas of ground collapse. It is found that when the soil layer is in low-or high-water content, the smaller the critical span of the underground cavity, the higher the ground collapse susceptibility. The evaluation results can provide suggestions for the prevention and treatment of ground collapse in Xi'an.