Analysis of failure mechanism of Qianjiangping slope based on improved failure approach index

作者：Zhang, Zhenhua; Qian, Mingming^*; Wei, Wei

来源：Chinese Journal of Rock Mechanics and Engineering, 2018, 37(6): 1371-1384.

DOI：10.13722/j.cnki.jrme.2018.0094

• Analysis of failure mechanisms
• Deformation of rock mass
• Failure characteristics
• Failure mechanism
• Qianjiangping landslide
• Slope engineering
• Three gorges reservoir
• Tri-axial compression tests

Qianjiangping landslide is the first large scale rock slide in the area of Three Gorges Reservoir(TGR) after impoundment. Most of the researchers agreed in the previous studies that reservoir impoundment and rainfall were two main factors triggering the landslide. However,there were different views regarding the degree of influence of two factors on the failure of the landslide,one considered that the influence of reservoir impoundment was greater than that of rainfall,the other considered that the influence of rainfall was greater than that of reservoir impoundment. In order to clarify this issue,the rock near the rock bridge that was part of the slip zone after sliding was selected. The triaxial compression tests on the influence of reservoir water immersion on strength and deformation of rock mass were carried out. The seepage field of groundwater and stresses in the slope under three conditions(reservoir impoundment,rainfall,and combined effect of reservoir impoundment and rainfall) were calculated with the software ABAQUS. Failure approach index was improved based on the constitutive relation of the rock obtained experimentally,and the improved failure approach index was applied to analyze the failure characteristics of the landslide under each condition. Under the influence of reservoir impoundment,the elastic modulus and shear strength of rock decrease remarkably when the rock is soaked. The influence of rainfall is greater than that of reservoir impoundment on the failure of the landslide,and the influence of combined effect of reservoir impoundment and rainfall is greater than that of rainfall. The sliding surface runs through under the combined effect of reservoir impoundment and rainfall. The study results suggest that the water immersion after reservoir impoundment reduced the strength of discontinuous rock bridges in the gently dipping discontinuous structural plane at the toe of the slope,the rainfall increased the sliding force of the slope,finally,the rock bridges fractured,and the failure of the slope occurred.

• 出版日期2018
• 单位合肥工业大学