Construction Risk Assessment And Stability Analysis Of High Rocky Slope With Weak Interlayer In Longyong Expressway

With the rapid development of expressway in China,the number of high cutting slope is increasing rapidly.The hydrogeological conditions of some high cutting slopes are poor.When affected by external forces or rainfall in the process of construction and operation,displacement and deformation of slope body will occur,further inducing serious geological disasters such as landslide and collapse.The slope instability disaster will greatly threaten people’s property and life safety.Scholars from relevant departments are paying more and more attention to the slope stability.At present,a large number of scholars have done a lot of research on the stability evaluation,failure deformation mechanism and protection measures of the slope based on different engineering practice,but there is little research on the high cutting slope with weak interlayer.This paper takes the high slope with weak interlayer between K57+030～073 as the research object,and carries out the construction risk assessment,stability and reinforcement measures research on it.The main work and conclusions are as follows:(1)Based on the investigation of geological exploration data,the geological structure,meteorological characteristics and design documents of the K57+030～073 high speed slope in longyong were introduced in detail,and the basic physical parameters of the main soil mass were obtained through indoor geotechnical tests.According to the guide issued by the ministry,the assessment factors of slope risk were determined,and the weight of each factor was assigned by grey relational degree method,and the assessment grade of slope risk was finally calculated(2)According to the engineering geological profile of a typical slope,a numerical model of a high slope without weak interlayer and with different inclinations,inclinations and buried depths containing weak structural plane is established to explore the influence of the existence of weak interlayer and its geometric distribution on the stability of the slope.The numerical model of slope excavation condition is established to explore the influence of each excavation process on slope stability.The numerical model of slope under different rainfall conditions was established to explore the influence of different rainfall time and rainfall conditions on slope stability.(3)According to the decision theory of entropy value method,the slope reinforcement measures are compared and selected,the slope anchor reinforcement model with different anchorage length and different anchorage Angle is established,the influence of anchor length and anchorage Angle on the slope stability is analyzed,and the optimal bolt arrangement scheme is determined.According to the reduction relationship between slope displacement and safety coefficient,the slope warning is divided into four grades,and the slope monitoring is carried out to verify the reinforcement effect.