Characteristics and the hazard-inducing effect of groundwater systems in Zongling high-level landslide areas

Taking two landslide areas of the Zongling collapse-landslide zone in Nayong county， Guizhou province as examples， this work conducted hydrogeological surveys， hydrodynamic field analysis， hydrochemistry research and flow dynamic comparative analysis to examine the hazard-inducing effect of groundwater. Results show that， （1） under natural conditions， there are three relatively independent groundwater systems in the collapse-landslide zone， while coal mining activities have changed the groundwater runoff-discharge direction， making the upper bedrock fissure water and middle karst water recharge into the lower bedrock fissure water， finally discharging to the surface from the pit or spring； （2） Flow dynamics and the variation of calcium ion content indicate that middle karst water in the rainy season recharges into the goaf tunnel in a injection form. They also show that vertical fractures developed in the shallow part of the slope body in the old Zongling town landslide area， as well as in the shallow to deep part of the slope body in the Zuojiazhai landslide area； （3） The groundwater flow in the Zongling landslide body is dominated by unsaturated groundwater seepage movement， no saturated groundwater flow field， thus no effect of the hydrodynamic driving landslides； （4） In the process of hazard initiation or triggering of the collapses and landslides in the Zongling area， groundwater plays a major role in accelerating and promoting development of vertical fractures and sliding structural plane， rock mass failure and instability. These research results are of certain significance to studies of the mechanism of collapses-landslides in the Zongling area and other karst mountainous areas with similar conditions in southwest China.