Slope Stability Analysis Of Silt Particle Flow Code Based On Strengh Double Reduction Method

Slope stability analysis is a hot topic in geological disaster research.China is a country with many landslides,which greatly threatens the safety of people's lives and property.It is of great significance to carry out the study on the sliding mechanism of landslides for disaster prevention and mitigation.Dry-wet circulation on the mechanical properties of impact of soil is irreversible,is one of the main factors of landslide disaster,will lead to the rise of ground water level,rainfall and high temperature under the action of water during the dry season will decline,experienced frequent dry soil evaporation and cause underground water level fluctuation and rainfall infiltration in the soil under the dry-wet circulation factors effect on the change of the physical and mechanical properties such as deformation and strength.This dissertation,taking a powder soil slope soil in Heilongjiang Province as the research object,through the indoor direct shear test with standard powder after wet cycle after dry strength index is the intensity attenuation law of fitting out of the silt strength index with dry and wet strength formula between cycles,starting from the mesoscopic mechanics level,bond strength double reduction powder soil slope stability theory research.The research results of this dissertation are as follows:(1)According to the indoor standard direct shear test,with the increase of drying and wetting cycles,the cohesion and internal friction angle of remolded silt are reduced at different rates.The reduction range of cohesion is up to 30%,and the internal friction angle is reduced by 12%.In the generation and development of silt landslide,the attenuation of cohesion is more obvious,and the change of internal friction angle strength is relatively stable.(2)Based on the particle flow theory,the relationship between macroscopic and meso-mechanical indexes of silt was obtained by parameter matching between test results of standards in the PFC5.0 program,and then the variation rule of meso-mechanical indexes affecting the strength characteristics of silt was obtained.According to the results of simulation parameters matching,mesoscopic parameters attenuation process is different,tangential bond strength is affected by dry-wet cycle compared with the normal bond stiffness value decreased significantly,the interparticle friction coefficient of contact,to a certain extent on the internal friction Angle of soil,reflect the shear strength of soil mass,the interparticle friction coef ficient is a declining trend,but the change in relative tangential bond strength is small.(3)Based on the strength double reduction theory,the micro mechanical characteristics of silt slope are analyzed.The morphological changes of silt slope in the process of its formation and development are studied.The whole process of slope instability is analyzed.The safety factor of slope is calculated by gravity increasing method and compared with the traditional calculation method.The simulation results show that P The safety factor obtained by FC program is less than that obtained by finite element method.The research results can provide reference for the stability analysis of silt slope.