Risk Evaluation And Control Of Highway Tunnel Construction

Based on the characteristics of tunnel construction,this paper analyzes the overall and major risks of tunnel engineering by means of risk identification,analytic hierarchy process(AHP),fuzzy comprehensive evaluation method and improved efficiency coefficient method.Based on the project of Si’Ao Tunnel in Zhujiajian Town,Zhoushan City,this paper summarizes the construction safety risk theory and evaluation method of highway tunnel,and establishes the overall safety risk assessment system of highway tunnel based on comprehensive fuzzy evaluation based on analytic hierarchy process(AHP).The evaluation system of major risk sources based on the improved efficiency coefficient method is established.Finally,the concrete method of safety management in the construction site of highway tunnel is put forward.The following results were achieved:(1)From the angle of "man-machine-environment-management",the risk identification of the whole construction process of Si’Ao Tunnel is carried out.Among the risk factors,13 influential factors,such as psychological quality,equipment operation state,construction operation environment,site management ability and system,are selected to analyze.The analytic hierarchy process(AHP)is used to construct the judgment matrix,and the weights of the risk factors are calculated.Then the fuzzy comprehensive evaluation method is used to obtain the overall construction safety grade of Si’Ao Tunnel is a medium risk.(2)In this paper,the traditional efficiency coefficient method has been improved,from the traditional two-grade standard value to five,and the corresponding fractional specific gravity has been adjusted at the same time.According to the expert investigation method and the engineering characteristics of Si’Ao Tunnel,this paper divides the risk sources which are easy to occur in the tunnel construction into two kinds,the risk of collapse and the risk of inrush of water and mud.The collapse risk is divided into five evaluation indexes.After the improved efficiency coefficient method is calculated,the final grade of collapse risk is grade Ⅲ.The risk of inrush mud is divided into four evaluation indexes.After calculation,the risk grade of gushing mud inrush is grade Ⅱ.(3)The method of pre-hazard analysis(PHA)is applied to the field safety control of tunnel construction,and the main nine stages of tunnel construction and the possible risks are listed.This paper makes a reasonable prediction on the event of risk triggering during the construction of Si’Ao Tunnel,the cause of risk formation and the grade of risk,and gives the corresponding control measures.