Revival Mechanism Of Old-large Landslide On Coal Mine Areas Under Multiple Incentives Conditions

There are many coal mines located directly in the toe of high and steep slopes or old landslide in China. Engineering activities (such as construction of caves、gangue filling、slope toe cutting), which make the geological disasters of slope failure or the old landslide resurrection happen occasionally. Concerned with large old landslides, normally it has a long cycle time for resurrected deformation, slip direction changes due to the conditions of stress field, and non-continuous multistage destruction which also bring many problems in stability evaluation and scientific prevention of the slope. This paper takes Zhujiadian mine landslide in Zhongyang County, Shanxi Province as an example and tries to figure out the engineering geological conditions in the landslide area, revival factors of landslide (such as the Geological conditions、the influence of coal mine tunnel excavatio、gangue load effects on the sliding body、the excavation impact analysis of the slope toe、acceleration action of the trailing edge cracks and the groundwater conditions), deformation failure characteristics (such as the broken of the buildings), and the spatial relationship between the engineering activities and landslide revivification through field survey and long-term monitoring. Furthermore, FLAC3D numerical simulation is conducted for analyzing the slope stability and deformation under different stress conditions, such as,caves construction、before and after the gangue filling and slope toe cutting. Under these simulations, this paper recreates the landslide of particle displacement, plasticity status and the shear strain increment, and characteristics of stress and displacement in the coal roadway located in the toe of landslide. Consequently, the result is consistent with monitoring results in the field. The following results were obtained:1. The revival of the Zhujiadian landslide was resulted from multiple factors. Sliding direction of the landslide turned to west during moving along the roadway. So it made the right side produce tensile stress concentration and compressive stress on the left.2. Traditional limit equilibrium methods can not solve the the stress concentration and deformation issues. Especially the old landslide was affected by a variety of stress in the process of reviving. In this paper, the landslide particle displacement, velocity vector and the stress-strain were analysed by numerical simulation. And it provided a theoretical basis for scientifically controlling landslide.3. The evaluation methods of numerical simulation technology and the on-site monitoring were necessary to the stability analysis for the landslide with multiple composite cause and stress field conditions.