A case study of super-high cut slope I：simulation and analysis of instability mechanism of slopes
WANG Hao1，2，WANG Xiaodong3，PAN Jun3
(1. College of Environment and Resources，Fuzhou University，Fuzhou，Fujian 350116，China；
2. Geological Engineering Research Center，Fujian Provincial University，Fuzhou，Fujian 350116，China；
3. Zhong Zi Hua Ke Traffic Construction Technology Co.，Ltd.，China Highway Engineering Consulting Corporation，
Beijing，100195，China)
Abstract：In this paper，the topography，landscape and geological conditions, and deformation process and failure characteristics of the super-high cut slope K227 along the expressway from Yongchun to Yongding in City Longyan of China were described. Simulation and quantitative evaluation of the deformation development of the slope were conducted with the back analysis for slope stability，the strength reduction method and the finite element modelling of excavation. A method based on the differential data of stress tensor is proposed to determine the relaxation zone due to excavation and to explain better the mechanism of unloading relaxation due to the excavation of the high cut slope. The numerical simulation faithfully reproduced the process and trending of the stress adjustment，plastic yielding，development of slip surface and deformation at all stages of the slope failure. The slope stability mildly increased in the unloading rebound stage，linearly reduced in the shearing failure stage and abruptly reduced in the instability stage. The numerical results demonstrated that the disturbance due to the fast excavation led to the potential weak layer to be fully exposed and cut off the mechanical support at the toe of the slope. The unloading relaxation and the weakened strength of the rock and soils resulted in the tension crack at the top，the shearing creep of deep weak layer and the shearing along the joints at the toe of the slope. The intermittent rainfall which increased the weight of the rock and soils and the extra pore water pressure caused the slope to slide intermittently. The slope is close to the limit equilibrium state globally and the stability may be abruptly reduced if further excavation or strong rainfall happen. Finally，the discussions and reflections on the emergency and rescue strategy，the planning of slope disaster mitigation methods and route adjustment are also presented.
王 浩1，2，王晓东3，泮 俊3. 超高路堑边坡治理工程案例研究I：边坡失稳机制模拟分析[J]. 岩石力学与工程学报, 2017, 36(4): 899-909.
WANG Hao1，2，WANG Xiaodong3，PAN Jun3. A case study of super-high cut slope I：simulation and analysis of instability mechanism of slopes. , 2017, 36(4): 899-909.
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2017, Vol. 36 
