Optimization On Safety-risk Assessment Index System For Argillaceous Siltstone High-slope Construction In Zhangsang Expressway

It is inevitable a expressway construction with the condition of complex natural conditions,along the line its safety particularly the high slope should be attached great importance by the highway management department.Slope risk assessment play an important role for guaranteeing the safety of slope construction.At present,the slope risk assessment index system is adopted widely by the Guide for Construction Safety Risk Assessment of Expressway High Slope Engineering(Hereinafter referred to as the Guide)in the engineering.However,it is found that several indexes are still lack of pertinence when the Guide was applied to the risk assessment of high slope of argillaceous siltstone in Zhangsang Expressway.Aiming to this thesis study taking the field investigation data,which for exploring the optimization on index' Weight Given Value and its dividing method of indicator threshold.The research contents and conclusions are mainly followed:(1)The reasons why the instability of typical argillaceous siltstone slopes are analyzed based on the field investigation of high cutting slope along the Zhangsang Expressway,then summarize the main influencing indexes of instability.These indexes can help for selecting risk assessment indexes and establishing index system.(2)Through the analyzing on main indexes of influencing instability,two evaluation indexes are proposed including strength characteristics and geometric features.Then analysising the indexes' weight given value results by Analytic Hierarchy Process(AHP).Its feasibility is verified in practical high-slope engineering.(3)Furtherly,strength characteristics,geometric features and groundwater are adopted to the risk assessment indexes,of which quantitative analysis and its changing law with slope safety coefficient is investigated.Use function of many variables on Taylor expansion to establish a multivariate linear regression model of strength characteristics and geometric features,which have a optimization on marking standard and threshold.Take groundwater as an single factor to analysis its impact on slope safety.The threshold and scoring criteria are pointedly redefined in the optimized risk assessment system.(4)Based on the argillaceous siltstone high slope engineering along Zhangsang Expressway,the optimizated system is applied on risk assessmen.The results show that the system have a better pertinence with the engineering practice.