Formation Mechanism And Prevention Countermeasures Of Karst Ground Collapse In Linyi Urban District

Karst collapse is a metamorphism on account of Karstification in Karst area. It is a kind of geological function that the geotechnical mass which above the Karst tunnel occurres ground deformation failure and lead to ground collapse pit under the natural and human effect. When it occurs in areas of human activity, they will destroy the land resources and their appurtenances, and endanger human life and property, to form Karst hazards.Karst collapse is a kind of important geologic hazard. This article based on the project of National Natural Science Foundation of China,"Study on the cause mode of formation and forecast,prevention and cure of the Karst collapse(Batch NAUMBER:40772145)",which made the Karst collapse in Linyi urban district for an example, guided by the principles of geology, we explored the factors and formation mechanism of Karst collapse by studying it's forming conditio,historical development,distribution and status; We should be propose a practical evaluation method by studying summary evaluation of Karst collapse in the past。The suffosion effect and the vacuum suction erosion effect were the formation mechanism of karst collapse in the region, others such as loss of buoyant force and increase the load effect, load effects and osmotic pressure effects are also important causes of karst collapse.This article believed that Karst collapse was affected by various factors, there had some random or non-deterministic that Karst collapse whether be happened or not in the study area, but we could still used the risk assessment to explain the risk probability of the Karst collapse. This article calculated the risk ratio by fish bone model, and then carried out collapse risk and vulnerability assessment through risk assessment model and vulnerability assessment model. We divide evaluated the hazard and vulnerability of the assessment area into five risk levels, then divided the assessment area into five levels according to risk and vulnerability Fish bone model of the risk assessment could effectively reflected the combined effect of the risk factor for the of regional risk, was a reliable, useful method.