Study On Karst Water Inrush Mechanism And Treatment Method And Its Engineering Applications In Tunnels

With the rapid development of the national infrastructure construction,especially the transportation infrastructure construction,China has become the largest and most difficult country in the area of tunnel construction in the world.Tens of thousands of kilometers of traffic tunnel engineering are or will be builded in the area of Western China,where the terrain and geological conditions are extremely complicated,that lead to the bad geological condition identify hardly in the early stage of tunnel construction.The causes of disaster and catastrophe process is extremely complex,resulting in the water inrush disaster occuring frequently in the construction of the tunnel and affecting the safety of tunnel construction.China’s transportation,hydropower tunnel construction of major geological disasters occurred in more than 100 times ten years ago in twenty-first Century.The water inrush and induced disasters accounted for 77.3%,nearly 1000 people was killed and injured,causing significant economic losses and bad social impact and damaging environment.The basic reason is that the deep tunnel water inrush is difficult to explore the occurrence of water inrush source and catastrophe evolution mechanism,the system has not yet formed.The grouting mechanism and the controlling technology has not become a system.It is difficult to prevent and control of disasters.This paper is based on the mechanism of water inrush,supported by the project of the Qiyueshan tunnel in the Hubei province expressway.Through laboratory experiments,theoretical analysis,numerical calculation,model test and field test methods.The paper research the filling disaster structure filling medium seepage failure mechanism,construction disturbance evolution process and water inrush the project early warning mechanism and study the mechanism of grouting based on the control principle and method.The paper established the key technology of grouting.The research results have a certain theoretical value and engineering significance,including:(1)The water inrush disaster sources types and occurrence characteristics is put forwad through the statistics of a large number of water inrush cases analysis.The internal structure of fault level geology and rock lithology is revealed and the distribution and characteristics of filling medium karst water inrush hazard source is builed.The distribution and occurrence features along the major water gushing disaster risk source is revealed combined with the analysis of the qiyue shan tunnel.(2)The filling type karst structure,established the filling medium seepage control equation,in-depth analysis of the seepage instability disaster evolution mechanism,the scour expanding seepage failure conditions and evolution characteristics,established the mechanical model of backfill and the overall outburst instability criterion,the system reveals the overall prominence of the catastrophe evolution mechanism.(3)A large-scale three-dimensional combined solid-liquid coupling test platform,a hydrostatic loading control system and materials such as solid-liquid coupled rocks and fillers which have high similarity under a hydraulic pressure environment are developed in order to study the catastrophic evolution mechanism and precursory rule of the water inrush in the cave during the construction disturbance and groundwater infiltration.The physical model test of karst ramming water induced by tunnel blasting is carried out,which reveals the dynamic catastrophic evolution mechanism of bursting induced by blasting.(4)A long-range monitoring and monitoring system for tunnel flood disaster is developed.According to the characteristics of engineering,such as survey and design,construction and monitoring,the "three-stage and multi-factor" early warning system based on regional geological information,advance forecast information,monitoring and measurement information and engineering information revision through the whole project construction process is established.Considering the strength of water inrush,the position of alarm and the time of prevention and control,the optimal escape route is put forward,and the comprehensive early warning system of the sudden flooding is formed,and the prevention and control measures and contingency plans are put forward.(5)According to the characteristics of the different types of flood water,the type of sudden water disaster is divided from the point view of governance,the diffusion law and plugging mechanism of grouting sealing slurry were revealed,the remediation technology of drilling and grouting is put forward,and the successful application is applied to the flood control of Xiangxi dam tunnel.