Formation Mechanism And Prevention Strategies For Collapse In Gently Inclined Red Stratum In East Sichuan Basin

Collapse disasters occurred frequently and threaten the safety of people's lives and properties In the red stratum of eastern Sichuan.There are many influencing factors of collapse in the red beds,the genetic mechanism and failure model is complex.In particular,the collapse most developed in gently inclined in red stratum,has more special genetic mechanism and failure model.But systematic research is relatively inadequate.Based on this,The purpose of this paper is to study the formation mechanism for collapse in gently inclined and advance prevention and control of the collapse accordingly.Provide theoretical and technical support for disaster prevention and mitigation of red beds collapse.this paper through the data collection and detailed investigation of 227 collapse in the stratum area of East Sichuan,studied the geological background and distribution law of the collapse also analyzed the conditions formation and the influencing factors of collapse.Classified and calculated stability of the deformation failure modes for existing collapse.Finally,statistics of the existing collapse prevention measures in the study area,and advance prevention of the collapse accordingly.Firstly,through field surveys and data analysis,Summarized the basic features and development laws of the collapse in red stratum of east Sichuan basin.The collapse disasters in the red stratum were widely spread over the middle and upper parts of the steep slopes,and were mainly small and medium-sized.Large and large-scale collapse disasters are rare.In this area collapsed disasters mostly occurred on the structures of gently inclined slopes.The instability mechanisms are mainly the translational,slip-pulling,and unloading-staggered breaking.Secondly,summarized the distribution laws and influencing factors of the collapse.The shape of the slope body,formation stratum group,weathering unloading,geological structure and rainfall are the main influencing factors of the collapse disaster in the study area.Studied the trigger mechanism and of collapse in gently inclined red stratum in east Sichuan basin.the main factor of translational collapse is the water infiltration of the trailing edge cracks.Rainfall infiltration and surface conditions are the main factors affecting the failure of sliding fracturing.the unloading-staggered breaking collapse is controlled by the key blocks,and the development of the dangerous rock is controlled by the deformation of the bottom soft foundation.Selected three typical case examples of collapses in the red stratum of eastern Sichuan,and analyzed the formation conditions and mechanism,also simulate the movement process of different collapse modes.by means of Discrete Element Method.Finally,a detailed investigation and comparison of the collapse protection engineering in the study area is carried out.Through the comprehensive analysis of the formation mechanism and the motion characteristics of the gently inclined collapse,the prevention and control measures of "Crack Filling + SNS + Drainage + Anti-slide pile " are suggested in the translational collapse,and the slip-pulling collapse is suggested to adopt " Crack filling + Drainage + Plain spray concrete +SNS"." Crack filling +Supporting + Drainage + Anchorage" measures are suggested for unloading faulting collapse.