FAILURE MECHANISM OF WATER-LEVEL FLUCTUATION ZONE WITH UMBRELLA-SHAPED ANCHORS UNDER RAPID DRAWDOWN BASED ON TRANSPARENT SOIL

The rapid drawdown of reservoir water can significantly influence the stress,seepage,and deformation of the water-level-fluctuation(WLF)zone,which affects the long-term stability of the reservoir bank slope. The umbrella-shaped anchor has ease of production and installation,and higher load capacity,so it has been gradually used to stabilize the slope. Thus,the deformation and failure mechanism of WLF zones can be reinforced by umbrella-shaped anchors under rapid drawdown conditions. Using transparent soil technology,we designed six physical tests of the WLF zone with umbrella-shaped cables considering different slope angles and anchoring spacings. We obtained the internal displacement,velocity in models using Particle Image Velocimetry(PIV)technology. We found:(1)The stability of the landslide obviously increased with the decrease of slope angle and anchor spacing. (2)There were three failure models of anchor-reinforced systems: total failure,local collapse and multi-sliding. (3)The sliding surfaces had deeper depth with the increase of slope angle because of the effect of the water rapid drawdown,and the umbrella cables obviously changed the shape and location of the sliding surfaces,and increased the landslide stability.