Study On Instability Mechanism And Stability Method Of Bedding Slope Of Red Stratum Soft Rock In Mid-Yunnan

With the rapid development of highway construction in southwest China,the problems of slope engineering during highway construction and later operation have become increasingly prominent.The problem of unstabla failure of bedding slope is particularly serious,which poses a serious threat to the engineering construction and the safety of people's lives and property.In the middle of yunnan,due to the special nature of the Red Stratum of Mid-Yunnan,the instability of the bedding slope is often affected by rainfall factors,and the abrupt instability of the slope is caused by the combined action of external and internal factors.Therefore,it is of great significance to study the abrupt instability of bedding slope in the red stratum of Mid-Yunnan area for highway construction.This paper takes the project of Yuchu Expressway Bidding Section in Yunnan as the background.Based on the hydraulic characteristics of the red stratum soft rock of Mid-Yunnan,this paper studies and quantifies the time history effect of the bedding slope stability of the red stratum soft rock of Mid-Yunnan under the condition of continuous rainfall.Based on the abrupt change of slope instability,combined with the catastrophe theory of nonlinear theory,the mechanism of instability catastrophe of red stratum soft rock bedding slope in Mid-Yunnan was studied.The typical soft rock slope in Yuchu expressway is used as the model for numerical analysis and verification.The work done in this paper is as follows:(1)Through the softening and disintegration test of the red stratum soft rock of Mid-Yunnan,the mechanism of water action on the hydrological characteristics of the red stratum soft rock of Mid-Yunnan was analyzed,and the linear relationship between the water content and the softening property of the red stratum soft rock of Mid-Yunnan is obtained.(2)According to the softening of soft rock,a formula for the progressive weakening effect of soft rock slope under the condition of rainwater infiltration is proposed,and the mechanism of the progressive weakening effect of rainwater infiltration is analyzed.Based on the hydraulic action of slope,the time effect of rainfall and groundwater on the red stratum soft rock bedding slope of Mid-Yunnan is analyzed.(3)Catastrophe theory is adopted as the stability analysis method of the red stratum soft rock bedding slope.Taking into account the complex influence of rainfall on the slope,a new cusp mutation model of the red stratum soft rock bedding slope of Mid-Yunnan was established.The mechanism and evolution process of slope catastrophe are analyzed.(4)Using FLAC3D on the typical working point slope simulation calculation analysis,combined with numerical cloud picture,red stratum soft rock of Mid-Yunnan bedding slope rainfall weakening mechanism and instability mutation were verified and analyzed.