Preliminary Design Stage Of Qianjiang-Enshi Expressway Yangtoushan Tunnel Safety Risk Assessment

Qianjiang-Enshi Expressway,from Qianjiang District of Chongqing City in the west,through Xianfeng County,Xuan'en County to Enshi Prefecture of Hubei Province,is about 130 kilometers long.It connects the two medium-sized cities of Qianjiang and Enshi,and connects Shanghai-Chongqing Expressway and Baomao Expressway(including Chongqing-Hunan Expressway).It is an important passageway for Southeast Chongqing and Northern Guizhou to enter Hunan.Based on the tunnel in the preliminary design stage of Qianjiang-Enshi Expressway,combined with the initial geological survey and design data of the project,and referring to previous engineering cases,this paper sorted out the possible risk sources and risk events in the preliminary design period of Niutang Tunnel,calculated and evaluated various risk sources and risk events,and put forward corresponding control measures for some possible major risks.To provide the basis for the construction management units and other relevant departments to make the next decision.The specific research results are as follows:(1)Summarizing and comparing the principles,steps and methods of tunnel engineering risk assessment and analysis,putting forward the steps and procedures of Tunnel Risk Assessment in the preliminary design stage of Qianjiang-Enshi Expressway,as well as the risk grading standards;investigating the basic situation of tunnel in the preliminary design stage of Qianjiang-Enshi Expressway,analyzing the geological conditions of tunnel and its design,drafting.Construction scheme;(2)The basic situation of the tunnel in the preliminary design stage of Qianjiang-Enshi Expressway,including the construction conditions of Engineering geology,hydrogeology and surrounding environment,was investigated,and the construction and operation risks of the tunnel were analyzed and evaluated by analytic hierarchy process(AHP),and the risk grade was determined.(3)In the preliminary design stage of Qianjiang-Enshi Expressway,risk sources such as tunnel survey and design,tunnel collapse,water inrush,mud gushing are identified,and corresponding risk levels are determined.That is,in the preliminary design stage of Qianjiang-Enshi Expressway,the risk levels of construction conditions ?Structural design scheme ?construction technology and Operations management are Grade ?.