Extra-long Karst Tunnel Water Inrush And Mud Outburs Risk Evaluation And Control Research

Water inrush and mud outburs are the most serious disasters encountered in the construction of tunnel engineering in karst region. The disasters will not only influence the construction progress but also put threat to all kinds of personnel who are working in the holes. And if no necessary measures are taken after the accident, it can also deteriorate both the ground surface environment and underground environment in the area of tunnel engineering. Therefore, it is imperative to study a scientific and universal method which can assess and further control and manage the risk of water inrush and mud outburs disasters in extra-long karst tunnel.In this paper, based on the LuoYixi tunnel engineering, we have carried through a research, which is aimed at water inrush and mud outburs disasters, including fuzzy evaluation of risk and corresponding control and management. The main research content is as follows:(1) The theories of both domestic and foreign scholars on extra-long tunnel engineering, disastrous mechanismsin karst tunnel engineering and risk evaluation are overviewed. And the existing problems in fuzzy evaluation of extra-long karst tunnel and control and management are that without an absolute objective risk evaluation method and a system of effective risk early warning system;(2) Geological environmental conditions of LuoYixi tunnel engineering are introduced. And according to the risk assessment standard by the ministry of transport of the People’s Republic of China in 2011,an overall risk assessment of LuoYixi tunnel has been made;(3) Aimed at water inrush and mud outburs, which is a specially high risk of karst tunnel, we choose the main risk factors to establish the hierarchical structure and then use FZ-AHP(Fuzzy Method Analytical-Hierarchy Process) to evaluate the risk.Put forward the three-stage dynamic evaluation to analyze the main risk factors of water inrush and mud outburs disasters in tunnel during three stages, which include the design stage, pre-construction stage and post-construction stage;(4) Risk control and management of water inrush and mud outbursare studied. Putting forward that the karst detection technology is an identification method of water inrush and mud outburs risk. A four-level comprehensive geological prediction scheme aimed at water inrush and mud outburs,risk early warning system and corresponding emergency response plan are proposed.