Research on influential factors of the karst collapse in the Tailai Basin of Shandong Province

The geologic disaster of karst collapse is a complicated process controlled by multiple factors. Though the karst collapse is influenced by many factors, it is largely controlled by the degree of karstification，the characteristics of overburden layers and the dynamic conditions (mainly groundwater dynamic condition). On the basis of previous studies and the latest investigation，this paper has analyzed the 3 influential factors and reveals the impact conditions and function on karst collapses. Results show that,(1) the karst collapses mostly develop in the locality with thick-layered limestone of high purity, while geological structure has an obvious control on the karst collapse; (2) the karst collapses in the study area mainly occur in Quaternary strata with multiple structures, followed by quaternary strata with unitary structure and dualistic structures. Moreover, karst the collapse occurred in the area of quaternary strata are less than 30 meters in thickness; (3) the karst collapse most frequently happen at where the cavern water level fluctuates around the bedrock surface. There is an approximately linear positive correlation between the natural logarithm of the karst collapse number and changes in cavern water level; there is also an approximately exponential positive correlation between the karst collapse number and natural logarithm of the exploitation modulus of cavern water. This paper can provide scientific basis for the integrated control of karst collapse in the study area.