Evolution Process And Displacement Back Analysis Of A Landslide On The West Side Of A Plant In Mao County

A factory in Mao county excavated the west side slope during the construction of the plant in 2011,resulting in large deformation of the west side slope.Immediately,the slope was treated with anchor piles,but the treatment effect was not ideal Several large deformations occurred between 2011 and 2018.The scale of the landslide continued to expand,the anti-slide piles were severely inclined,and the anchor cable failed.Then,in 2018,emergency anchor cables were applied for treatment,but the landslide was still slowly deforming.This thesis takes the landslide on the west side of a factory in Maoxian as the research background,analyzes the evolution process of the landslide based on relevant data and field investigations,and uses the structural mechanics method and numerical simulation method to analyze the cohesion c and internal friction angle ? of the landslide based on the measured displacement data.Perform displacement back analysis.The main work of this thesis is as follows:(1)During the landslide site survey,the landslide's elements,crack distribution,and deformation of supporting structures were investigated and counted.According to the survey content and the previous geological survey report,the evolution of the landslide from 2011 to 2018 was qualitatively analyzed,and the development process of the landslide was divided into four stages.The reasons for the formation of the landslide and the influencing factors were analyzed.(2)The displacement back analysis is carried out for the three stages of the landslide deformation.The deformation of the anti-slide pile at the leading edge of the landslide is used as the entry point to establish a structural mechanics calculation model.The landslide thrust received by the anti-slide piles,then the main section of the landslide is divided,and the transfer coefficient method is used to calculate the sliding force of the last block of the landslide under different combinations of c and ? samples.The back-calculated anti-slide piles have the same thrust.At this time,the combination of c and ? that meets the requirements is not the only solution.The dimensionless parameter ? is introduced again,and the ratio of c to tan? is constant when the landslide shape is unchanged.Therefore,the unique inversion values of shear parameters c and ? of the landslide can be determined.The inversion value was brought into the newly added anti-slide pile for calculation.The relative error between the calculated value and the measured value was 7.7%,indicating that the result was reasonable.(3)A three-dimensional finite element model of MIDAS/GTS for landslides is established,and the inversion parameter samples are constructed using the golden section method.The displacement objective function is used to reflect the error between the calculated value and the measured value.Through continuous iterative calculation,the objective function meets the accuracy requirements.The c and ? values are the inversion results.During the failure stage of the anchor cable,inversion of rock and soil parameters at different depths shows that there is a difference in the spatial distribution of the shear parameters.The closer to the sliding surface,the lower the shear parameter values of the rock and soil.A numerical simulation including the newly added anti-sliding pile is established,and the inversion value is taken into account for calculation.The calculated displacement value at different depths of the loaded section is compared with the measured displacement value,and the relative error is between 8% and 19%.