Regional Dynamic Risk Assessment And Early Warning Of Tunnel Water Inrush And Application

With the national strategy of infrastructure construction to the depth development of the western region, karst is one of the most frequent and biggest defective geological in tunnel construction process, which often breeds the occurrence of water inrush and mud resulted in huge casualties and property losses. Because of its sudden and difficult to predict characteristics, water inrush has caused catastrophic challenges in the construction and operation period, the study of forecast and precaution method of water and mud bursting is the most effective way of prevention and control of water and mud bursting disaster.(1) Based on each section information after section partition divived by geological structureand of tunnel, the most appropriate risk assessment methods for risk assessment of water and mud bursting disaster is selected. Four most commonly used methods of risk assessment including analytic hierarchy process (AHP), fuzzy comprehensive evaluation method, attribute synthetic assessment method, extension theory are summarized and analyzed that whose applicable conditions are studied to provide a standard for the regional risk evaluation of tunnel.(2) The failure modes of water inrush in tunnel are divided into water resisting rock rupture instability and water resisting rock mass loss seepage instability. The studies showed that some obvious precursory information of physical field and geological field have appeared before the occurrence of water inrush and mud happened. The precursory information of physical field such as displacement, seepage pressure, stress, strain and geological field are selected as early-warning index of inrush water bursting. The importance of the multi-source precursory information caused by the different failure modes which have a guiding role in scientificly designing e component layout scheme is different.(3) According to the risk assessment result for high risk, the remote intelligent monitoring system of tunnel water and mud inrush is founded based on IOT in the section. The front-end acquisition system composed of sensor networks including displacement, water pressure, stress, strain and HD camera acquires multi-source heterogeneous precursory information in the real-time. The remote wireless transmission system consisting of MCU data acquisition nodes, wireless relay and the remote base station real-timely uploads collection of precursory information to the cloud platform of early-warning analysis of tunnel water inrush. Achieving the wireless remote real-time transmission provides on-site technical support for real-time warning of water inrush hazard.(4) The critical hazard identification theory of water inrush is established which is divided into four-color early-warning level of the single index early-warning level classification of the displacement, seepage pressure, stress, strain precursory informationnd multi-index comprehensive early-warning level classification, and then determines the coupling early-warning level of risk assessment level and multi-source heterogeneous precursory information of water inrush hazard.(5) Based on C# programming language, the multi-source precursory information early-warning analysis system of tunnel water inrush is developed which designs the management system, project management, real-time monitoring, alarm setting, and data management module. Based on B/S architecture design, the docking of cloud platform and remote intelligent monitoring system of tunnel water inrush disaster is realized, so that the multi-source precursory information of tunnel water inrush carries out the real-time display and analysis of precursor information. What’s more, the critical early-warning threshold of tunnel water inrush is embedded in the early-warning setting module, which will be early warning when the monitoring data reached critical threshold of warning level. In the meanwhile the corresponding warning level shows.(6) Based on a tunnel of Cheng-Lan railway in Sichuan Province under the river crossing, the field test of remote monitoring and forecasting early-warning system has a significant influence on the study of water inrush early-warning method.