Evaluating the stability of Outang landslide in the Three Gorges Reservoir area considering the mechanical behavior with large deformation of the slip zone

Abstract

The large deformation mechanical properties of slip zone soil play an important role in the stability evolution of landslide. The traditional landslide stability evaluation method can only be used to calculate a single stability factor, which cannot dynamically evaluate the landslide stability as it evolves. The large deformation mechanical properties of slip zone soil from Outang landslide in the Three Gorges Reservoir area are investigated by the indoor repeated direct shear test. Based on the damage theory, the shear damage behavior of slip zone soil with large shear displacement is analyzed, and a mechanical model describing the relationship between shear stress and shear displacement in accordance with the mechanical mechanism of landslide is established. Then, the stability of Outang landslide is dynamically evaluated by skillfully combining the mechanical model and the residual thrust method. The results show that the slip zone soil has obvious softening behavior and constant residual strength under the condition of large deformation. The model with clear physical meaning can reflect the large displacement shear mechanical properties of slip zone soil, which is consistent with the test results. The stability factor of Outang landslide gradually decreases and tends to be constant as landslide moves. The mechanical mechanism of the landslide stability evolving with deformation is the strain softening behavior of the slip zone soil, and the mechanical mechanism of the landslide stability evolving with water level is the reduction of effective stress in anti-sliding section under the influence of reservoir water. It is suggested that active measures should be taken in time in the prevention and control of landslide, and the construction of drainage engineering should be paid attention to for large-scale bank landslides.

Progressive evaluation of buckling landslide stability considering strain softening behavior of the slip zone

“…In the above shear constitutive model of slip zone soil, $${K_{\rm{s}}} = \frac{{{G_{\rm{s}}}}}{h}$$, 25 where the shear modulus ( G s ) is a constant, so the shear stiffness ( K s ) is inversely proportional to the slip zone thickness ( h ). By comparing the shear stiffness ($${K_{\rm{s}}} = \frac{{{G_{\rm{s}}}}}{h}$$) corresponding to the average thickness ( h ) and the shear stiffness ($${K_{\rm{s}}}^\prime = \frac{{{G_{\rm{s}}}}}{{h^{\prime}}}$$) corresponding to the thickness h ', it can be obtained that: $$\begin{equation}{K_{\rm{s}}}^\prime = \frac{h}{{h^{\prime}}}{K_{\rm{s}}}\end{equation}$$where K S ' is the shear stiffness corresponding to h '.…”

“…Based on the damage theory, reported studies have proposed a shear constitutive model of slip zone considering the shear mechanical behavior with large displacement. 25 The shear constitutive model can quantitatively describe the relationship between shear stress and shear displacement during the shear deformation process of slip zone soil with strain softening characteristics (Figure 2). The shear constitutive model of slip zone soil is as follows:…”

“…This study puts forward a progressive stability evaluation method for buckling landslide considering the mechanical characteristics of strain‐softening of slip zone based on the energy conservation theory and shear constitutive model 24–26 . Considering Baiyangou landslide a case study, the progressive stability evaluation method is proposed for buckling landslide in the process of deformation.…”

“…This study puts forward a progressive stability evaluation method for buckling landslide considering the mechanical characteristics of strain-softening of slip zone based on the energy conservation theory and shear constitutive model. [24][25][26] Considering Baiyangou landslide a case study, the progressive stability evaluation method is proposed for buckling landslide in the process of deformation. First, the critical displacement of Baiyangou landslide when the stability coefficient is 1 was calculated and compared with the measured sliding distance before the destabilization of landslide to validate the model.…”

Prediction and Analysis of Slope Stability Based on IPSO-SVM Machine Learning Model

“…To prevent or alleviate the occurrence of slope disasters, it is of great significance to provide timely and accurate predictions of slope stability. In recent years, Chinese and foreign scholars have continuously established new research models in the study of slope stability evaluation through combining interdisciplinary knowledge, effectively promoting the development of slope stability evaluation study [1][2][3][4][5][6][7]. At present, the evaluation and prediction methods of slope stability include the rigid limit equilibrium calculation method and the elastic-plastic theoretical calculation method.…”