Experimental Study On Shear Strength Characteristics Of Loess With Humidification

Loess is widely distributed in China,especially in the northwest region.Loess has various properties,among which its water sensitivity causes changes in its strength after immersion,leading to geological disasters such as landslides and collapses,which can also affect the construction progress in actual engineering construction.Therefore,research on the mechanical properties of loess is gradually receiving attention.The wetting and shear properties of loess have been an important topic in soil mechanics research in recent years.In terms of shear characteristics,the failure of loess structure caused by humidification is one of the main reasons for shear failure of loess.Many scholars at home and abroad have conducted in-depth research and analysis on the deformation characteristics and mechanisms of loess during the shear process,but the relevant research on the changes in shear strength of loess caused by humidification is still incomplete.Currently,more experimental research is needed to provide theoretical support.Therefore,this article takes Taiyuan loess as the research object,and based on the engineering characteristics of loess,conducts research from both indoor experiments and numerical simulations.The variation law of shear strength of loess under different influence factors is studied through ring shear test.Through direct shear test and triaxial test,the changing characteristics of shear strength of loess under the effect of humidification are studied,and the relevant laws and mechanism of the change of shear strength of loess caused by humidification are revealed.Using the finite element software Midas GTS NX to simulate the triaxial test of loess,and comparing the simulation results with the triaxial test results,this study explores the law of shear strength loss of loess caused by humidification(or immersion),providing theoretical support and academic reference for disaster prevention and reduction of rainfall instability of loess slopes.The main research content of this article is as follows:(1)Using a ring shear apparatus to conduct shear tests on loess,this study explores the effects of different test conditions on the shear strength of loess,analyzes its variation patterns,explores the characteristics of the shear strength indicators of loess with changes in moisture content,and obtains corresponding shear strength parameter values,providing experimental data for subsequent wetting shear tests.(2)The modified stress controlled direct shear apparatus is used to conduct wetting shear tests on loess.Based on the shear strength theory of loess,wetting shear tests are carried out under different axial stress,shear stress and dry density,and the variation law of shear strength of loess under different test conditions is analyzed.(3)The consolidation undrained test of loess is carried out by using an automatic triaxial apparatus to explore the change of shear strength of loess under different influence factors in triaxial test and analyze its change law.(4)Based on the parameter values obtained from the above triaxial test,Midas GTS NX was used to simulate the triaxial test of loess,analyze the stress cloud map changes of loess under different test conditions,and verify the reliability of the indoor triaxial test results.