Study On Stability Of Silty Clay Slope In Alpine Region

In recent years,China’s central and western regions have made great efforts to develop and achieve rapid economic growth.According to the national highway network planning(2013-2030),several new expressways and national highways will be built in the alpine tundra.In these highway construction projects located in the alpine regions with seasonal temperature changes,the road slope formed is subjected to freeze-thaw cycle,and the original stability of the slope is changed due to the cold generation of soil structure.Even today when the research on slope stability is relatively mature,engineering accidents still occur frequently in the high and cold area.Therefore,it is necessary to study the slope stability in the cold region.According to the actual situation of freezing and thawing of the slope in the alpine region for a long time,the soil mechanical properties are changed from water content and freeze-thaw cycles,and the influence of external conditions on the shear strength of the soil is analyzed,and then the alpine region is analyzed.The stability of the clay slope,the specific content and results of this paper are as follows:1.Analyze and compare the slope stability analysis methods to find the factors that affect the slope stability.The finite element method of strength reduction is used to study the geometric factors affecting the slope stability and the soil mechanics parameters.The single factor sensitivity analysis is used to obtain the influence degree of the influencing factors on the slope stability,from large to small: Slope slope coefficient > cohesion > slope height > internal friction angle.2.For the slopes that have been put into use,the shear strength parameters of the slope soil and the internal friction angle are the main factors affecting the stability of the slope.Therefore,the effects of water content and freeze-thaw on the shear strength of soil were analyzed by freeze-thaw test and direct shear test on silty clay.The research shows that the soil cohesion and internal friction angle decrease with the increase of water content;as the number of freeze-thaw cycles increases,the shear strength parameters of silty clay also decline,but finally reach new The stable equilibrium state;the higher the water content,the more obvious the attenuation of the shear strength of the soil by freezethaw.According to the test results,the relationship between the cohesion force and the internal friction angle and the water content is obtained,and the attenuation formula of the cohesion force and the internal friction angle under the freeze-thaw cycle is obtained.3.Establish a slope model for numerical analysis,introduce the attenuation law of shear strength parameters,and analyze the stability of silty clay slope.The study shows that with the increase of soil water content,the stability coefficient of the slope reaches the limit state,which is not conducive to the overall stability of the slope;the freeze-thaw cycle significantly reduces the overall stability of the silty clay slope,but As the number of freeze-thaw cycles increases,the effect of freeze-thaw on the attenuation of slope stability becomes weaker.4.According to the numerical simulation results,the correction coefficient of silty clay slope stability in the alpine region is defined from the water content and the number of freeze-thaw cycles.According to different engineering grades,the stability safety factor of the slopes with different combinations is corrected.The construction and maintenance of silty clay slopes in the region have reference value.