CHARACTERISTICS OF LANDSLIDE DEVELOPMENT AND MECHANISM OF TYPICAL LOESS LANDSLIDES IN BINCHANG AREA

In order to reveal the mechanism of loess landslide disaster in Binchang area, based on the analyzing the characteristics of landslides and distribution, typical loess landslide cases were studied using field investigation and theoretical analysis method. Analysis were made for the activation mechanism of the excavation loess landslide, the mining type loess landslide and the active loess landslide in goaf. The results show that:in the unloading process, the stress at the toe of the slope appears concentrated, and the pulling tension cracks appear on the top of the slope, while the pressure on the toe of the slope is strengthened. The fracture and compressive stress increase alternately, causing mutual cause and effect until they develop into an upward and downward crack zone, and the entire slope is unstable. In the mining disturbance, the overlying rock instability caused by the uneven settlement of the surface layer of loess, the displacement vector of slope direction on both sides of the valley in the goaf center and the inclination along the slope of the displacement vector dynamic superposition under the action of failure, after the arrival of the side slope mining often early in the first to one side slope landslide. Gob activation of loess landslide occurs mainly in the upper goaf of the Loess Plateau, the relative stability of the goaf, the infiltration of surface water and underground water level. Under the conditions of surface water infiltration and groundwater level uplift in relatively stable goaf, the coal pillar is unstable and collapses under the action of hydrodynamic erosion, and the stress of the rock mass is redistributed, which causes the two times of the surface loess layer to be unstable and eventually triggers the landslide.