Research On Strength Parameters Inversion Methods For Landslides After Earthquake

The landslide stability and supporting calculations depend on strength parameters of sliding zone soils seriously. Currently, inversion method is an important mean to determine the strength parameters of sliding zone soils. The limit equilibrium inversion which bases on global safety factor and the intelligent displacement inversion are normally used nowadays. Limit equilibrium inversion can’t establish a direct relation between the sliding mechanism and strength parameters, and parameters are always lower than the reality. Because of the less sensitive between strength parameters and the displacement, the results of intelligent displacement inversion are not satisfactory.In this thesis, different forms of the landslides derived from the sliding mechanism, and strength parameters determine the sliding mechanisms are found by collecting and analyzing of a large number of domestic and foreign literatures. Therefore, the new idea of strength parameters inversion from the mechanisms of sliding is proposed in this thesis.Actually, sliding mechanism can be represented through the cracks on the surface of the slope, and the intrinsic is reflected in the stress field. Sliding mechanism is depended on the strength parameters. After the analysing of three-dimensional stress state, the method called point safety factor whice is proposed by Yang Tao is used to quantitativly descrip the different mechanisms of sliding. The distributions of the sliding zone point safety factors under different sliding mechanisms are different. So, the relationship between the point safety factors and sliding mechanism becomes the strong evidence that strength parameters can be inversed by point safety factors. By a large number of numerical simulations on different parameters, influences of various parameters on the sliding mechanism are fonud in this thesis. These results can guide the strength parameters inversion.A point safety factors inversion method of strength parameters of sliding zone soils that based on sliding mechanism is proposed in this thesis. In addition, the block limit equilibrium method is used to select the best resultes. By using this inversion, the sliding mechanism, global stability factor and the distributions of cracks must be satisfied simultaneously, and then the corresponding strength parameters are the reasonable inversion results. Finaly, by analysing the1-1cross-section of1#landslide in State Road214of K822+888-K824+400paragraph which links Gu Jie and Ba Tang, get the sliding zone strength parameters by point safety factors inversion which is proposed in this thesis, and the rationality of this method is proved.