Effect Of Dry-Wet Cycle On Landslide Soil Strength And Landslide Stability Analysis In Three Gorges Reservoir Area

With the the Three Gorges Dam was construction,the reservoir bank landslides in the Three Gorges Reservoir area have been in a state of dry and saturated for a long time in the environment of long-term reservoir water level elevation and periodic rainfall.This state will definitely affect the physical properties of the landslide soil.Thereby affecting the stability and characterization of landslides.In this paper,the landslide soil of Tangjiao No.1 landslide in Wanzhou District of Chongqing City is taken as the research object to study the change law of the shear strength parameters of the soil body under the dry and wet cycle and the stability of the landslide under the dry and wet cycle.The test used in this article is an indoor triaxial test.The stress-strain curve of the sample and the cohesion and internal friction angle of the sample can be obtained.By collating the obtained data,PLAXIS 2D can be obtained in different dry and wet cycle states The numerical simulation software can obtain the plastic deformation law of landslides in different states and the stability changes of landslides.The actual results obtained are as follows:(1)The shear strength parameters decrease gradually as the number of dry-wet cycles increases.In the study of the effect of the number of dry and wet cycles on the soil,it was found that as the number of dry and wet cycles increases,the main stress difference,cohesion,and internal friction angle gradually decrease;after one dry and wet cycle,the main The magnitude of the decrease in stress difference,cohesion,and internal friction angle was the largest.After 3 dry-wet cycles,the reduction was significantly reduced;the cohesion and internal friction angle became stable after 7 dry-wet cycles..(2)The shear strength parameters gradually decrease with the increase of the amplitude of the dry-wet cycle.It is obtained in the experiment of studying the effect of the amplitude of the dry-wet cycle on the soil.As the amplitude of the dry-wet cycle increases,the main stress difference,cohesion,and internal friction angle decrease gradually;the main stress difference increases with the The increase of pressure gradually increases,and the cohesion and internal friction angle decrease with the increase of the amplitude of the dry and wet cycle,and the faster the decrease;after 7 dry and wet cycles,the cohesion and internal friction angle are affected by the amplitude of the wet and dry cycle Not big,but the value still tends to decrease.(3)As the number of dry and wet cycles increases,the plastic deformation area of the landslide gradually increases.As the amplitude of the dry and wet cycles increases,the plastic deformation area of the landslide also increases gradually under the same number of dry and wet cycles.When the number of wet cycles is relatively small,the change tends to be less obvious.Looking at the plastic deformation area of the two slopes,the larger the slope,the greater the total displacement and deformation.(4)With the increase of the number of dry-wet cycles,the stability coefficient of the landslide gradually decreases.As the amplitude of the dry-wet cycle increases,the stability coefficient of the landslide gradually decreases.The greater the dry-wet cycle amplitude,the greater the stability of the landslide.The greater the reduction of the coefficient,The wet-dry cycle has a great influence on the slope stability.