Grey relational grade theory-based risk assessment of ground fissures in Suzhou-Wuxi-Changzhou area

Su-xi-chang area is one of severe ground fissure areas in China, has caused great economic losses to the production and living of the local residents. The grey relational grade theory was used to analyze the ground fissures in the area. Based on the analysis of the formation conditions of the ground fissures in the area, six impact factors were selected:the depth of the bedrock, the roughness of bedrock surface, the thickness of the second confined aquifer, the thickness of clay soil, the depth of ground water level below the ground surface and the gradient of land subsidence. Then, the correlation degree and influence weight of each impact factor were calculated, and the dangerous extent of the ground fissures was evaluated in the subareas of the Suxichang area accordingly. The entire study area was divided into the safe, transitive, more dangerous, and the most dangerous subareas of the ground fissures. The quantification of the factors affecting the development of ground fissures in Su-xi-chang area was studied through the grey relational grade theory, which provides a theoretical basis for the prevention and control of ground fissure disasters.