Research On Genetic Mechanism And Risk Evaluation Of The Karst Collapse In Guanghua Basin

The karst collapse is one of the primary geological disasters in soluble bedrock. With the urban-rural integration of Guangzhou city, rapid development of urban construction and enhancement of human activities, the number of human-induced karst collapses in soluble bedrock of Guanghua Basin has been increasing year after year. These disasters have severely restricted the local construction and economic development. It will be of great significance to scientific construction and sustainable development of Guangzhou city to research on the genetic mechanism of karst collapse, evaluation of geological disaster risk and risk management model of the city safety.Supported by "Geological Disaster Survey and Risk Assessment of Guangzhou City", the subtopics of "Urban Geological Survey of Guangzhou City", and based on a comprehensive survey of geological disasters in Guangzhou, this paper mainly studies the karst collapse in Guanghua Basin, upon which geological disaster database is built. Further, the paper discusses the genetic mechanism of karst collapse, and evaluates the risk of karst collapse in Guanghua Basin.This paper, integrated with an overall survey of collapse, analysis of geological environment conditions and ground water hydrodynamics, researches the genetic mechanism with the application of ground subsidence monitoring and ground water pressure auto-monitoring. It summarizes the several causes of karst collapse, including float-losing and load increasing, underground erosion, vacuum negative pressure suck erosion and air explosion, mechanical perforation, earthquake and vibration, loading, integrated superposition, etc. Besides, the author proposed a special collapse mechanism for Guanghua Basin - mechanical perforation. A karst collapse disaster database is built for this project. And also, the analytic hierarchy process is induced to develop the risk evaluation system of karst collapse. With the relativity analysis of geological background factors, human factors and frequency of occurred collapses, the paper firstly confirms basic factors, response factors and induced factors, which are weighted separately, to construct the risk evaluation indicator system. Secondly, with the risk evaluation system, this paper assesses the fatalness, vulnerability and risk of the collapse disaster, based on which Guanghua Basin is divided into high risk area, relative high risk area, medium risk area and low risk area.Combined with the research of genetic mechanism and disaster risk evaluation zoning of Guanghua Basin, the paper puts forward effective measures for the karst collapse prevention and risk management in the process of urban development and construction in soluble bedrock area. It will be of great guiding significance to the effective collapse prevention, motoring and warning the disaster, and the site selection, investigation, design and construction for the urban construction project.