Evaluation of susceptibility to karst collapse on both sides of the Yangtze River in Baishazhou, Wuhan and preventive measures in the process of metro construction

In recent years, during urban engineering, there have been frequent karst collapses in Wuhan city, which seriously affects urban development and citizens security. In order to ascertain the susceptibility zone of ground collapse in karst area and put forward prevention measures, the Baishazhou karst belt along the Yangtze River is taken as the study area, and 7 indicators (karst development, soil thickness, soil structure, red-strata thickness, groundwater level fluctuations, karst water level fluctuation position and the density of collapse pit) are considered as evaluation factors. Based on this, a multi-factor discriminative model of karst collapse development is established employing analytic hierarchy process, and the study area is divided into different regions with high, medium and low susceptibility through GIS spatial analysis technology. Corresponding countermeasures and suggestion are proposed on the basis of geological structure for characteristics in different stages of the subway project in the region and their different sections of the susceptibility. The result shows high-susceptibility parts are mainly located in the covered karst area on both sides of the Yangtze River, and mostly contain sandy soil. High-susceptibility parts are the key of prevention and treatment, therefore, this area should be avoided during the planning phase, and the principle of prevention and control is mainly to prevent the leakage of the overlying sand particles. The principle of moderately susceptible zoning prevention is to prevent the formation and development of soil cavities in a single clay soil and to protect the integrity of the red layer. The thickness of the red layer for low susceptibility is greater than that of the engineering construction entering the bedrock, and the possibility of karst collapse is minimal. Our study can provide a reference for the constructions on the banks of the Yangtze River in Baishazhou, Wuhan.