| The railway tunnel generally passes through complicated geological conditions areas and the construction risk is exceedingly high.It is easy to take place the construction risk accidents such as face instability,water inrush,mud inrush,collapse and falling block.In the course of tunnel construction is easy to occur such construction risk accidents as tunnel face instability,water or mud burst,collapse and falling block.Based on the characteristics of the disaster of Monghua railway Pengjialing 2 tunnel,an accident probability assessment model is established by fuzzy analytic hierarchy process and an accident consequence assessment model is established by the equivalent risk consequence estimation method,and the construction risk classification is divided according to 《Technical code for Risk Management of Railway Tunnel Engineering》.Monghua railway Pengjialing 2 tunnel is 2108-meter,the whole depth of the tunnel is relatively large,and geological complex.By analyzing the poor geological conditions of Monghua railway Pengjialing 2 tunnel,the tunnel is divided into many parts.Based on the established risk assessment model of railway tunnel construction,the risk assessment of each section of the tunnel is determined,Based on the results of comprehensive advanced geological forecast,the conclusion of risk assessment is revised to finally develop the risk treatment technology of tunnel construction.the main research results are:(1)the main adverse geological conditions of Monghua railway Pengjialing 2 tunnel are analyzed to provide theoretical basis for the rational use of risk treatment measures,especially for the use of comprehensive advance geological prediction methods.(2)The fuzzy analytic hierarchy process is used to establish the risk probability assessment model of railway tunnel construction,in which the scale of each risk factor is determined by analytic hierarchy process,the membership degree of quantitative factor is determined by trapezoidal distribution function,and the membership value of qualitative factor is determined by fuzzy membership function.Based on the concept of "equivalent",the contingency estimation method is used to establish the accident consequence evaluation model for the non-uniformity of the measurement methods.(3)The advantages,disadvantages and applicable conditions of each geological forecast method are summarized and analyzed.According to the construction risk assessment grade of each section of the railway tunnel,different comprehensive advanced geological forecast with different risk grades is developed.These methods have been applied in the Monghua railwayPengjialing 2 tunnel,and obtained good forecast effect.Based on the results of comprehensive advanced geological forecast,the risk assessment conclusions are revised.(4)The potential risk factors and treatment measures in the construction of railway tunnel are analyzed in detail.These risks mainly include: tunnel face instability,water or mud burst,collapse and so on.Based on the results of comprehensive advanced geological forecast,the risk assessment conclusions are revised.By comprehensively considering the construction risks and grades that may be encountered in the Monghua railway Pengjialing 2 tunnel,the author guides the treatment of potential risk factors and establishes different types of disaster prevention measures,which is expected to bring reference value to the railway tunnel construction. |
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