Stability Analysis And Risk Assessment Of Gently Inclined Mudstone Bedding Highway Slope

The gently inclined bedding slope is widely distributed in Guizhou Province.Because of its complex formation mechanism and difficult identification,it is not easy to be discovered in the geological disaster survey and early identification.However,once the slope is unstable and damaged,it will cause great harm and serious consequences,Therefore,the failure mechanism,monitoring and early warning,risk assessment of gently inclined bedding slope have become the urgent problems to be solved in the construction and operation of mountainous highway.This paper deeply excavates and analyzes the engineering status and monitoring data of the slope,analyzes the influencing factors of the gently inclined mudstone bedding highway slope,reveals the failure mechanism and failure mode of the gently inclined mudstone bedding highway slope,establishes the comprehensive risk evaluation model of the gently inclined mudstone bedding highway slope,and carries out the comprehensive collaborative evaluation of the slope from the quantitative and qualitative perspectives.The main research results are as follows:(1)Based on the analysis of engineering geological conditions,hydrogeological conditions and engineering status,this paper analyzes the influencing factors of gently inclined mudstone bedding slope,and obtains that the failure mode of gently inclined mudstone bedding highway slope in the study area is "slippage-tension fracture" mode,which reveals the instability mechanism of gently inclined mudstone bedding slope under the conditions of excavation unloading and rainfall.(2)Through the design of on-site monitoring scheme and the processing of on-site monitoring data,the whole process cumulative displacement-time curve of gently inclined mudstone bedding slope is obtained,the characteristics and laws of deformation curve are revealed,and the early warning criterion based on deformation rate and improved tangent angle is established,so as to realize the accurate early warning of imminent sliding of gently inclined mudstone bedding slope.(3)Based on the finite element software MIDAS GTS NX,the instability failure model of the slope of the gentle mudstone bedding road is established.The stability of the slope under different rainfall duration and the support of the prestressed anchor cable frame beam is simulated by using the stress-seepage and strength reduction method.The effectiveness of the prestressed anchor cable frame beam supporting the slope of the slow dip mudstone along the road is verified.(4)Based on the failure mode and influencing factors of the gently inclined mudstone bedding highway slope during the operation period,the key evaluation indexes are extracted,and the risk evaluation system of the gently inclined mudstone bedding highway slope is established.The weight and membership degree of the slope risk evaluation indexes are determined by monitoring and early warning,stability evaluation and hierarchical fuzzy evaluation,the "qualitative plus quantitative" comprehensive collaborative risk assessment of gently inclined mudstone bedding highway slope in operation period is realized.