Stability Study And Processing Technical Of Imminent Unstable High Steep Rock Slop

The imminent unstable high steep rock slop is the imminent unstable and destruction probability P_f>30% natural or artificial slop which is composed natural rock mass and more than 70m high, slop angle more than 45°, is direct correlated to project safe.The rock mass of the imminent unstable high steep rock slop is encountered many times geology function, undergoing distorts, destroys and forms certain mineral, structure geologic body, which in certain geological environment. The distortion and unstability is a complex, irreversible, the dynamic diffusion process. The unstability influence factors of the imminent unstable high steep rock slop are terrain landform, geologic structure, lithology, rock mass structure, characteristic of structural plane, crustal stress and water. The stress distributes during the forming process of the imminent unstable high steep rock slop lead to form tensile stress area and shearing stress centralized area in the slop, which does not favor the stability of the slope.During or after forming the imminent unstable high steep rock slop, the slop is encountering epigenetic reformation. The unstability of the imminent unstable high steep rock slop includes distortion and destruction. There are not penetration failure plane in the slop is called distortion, which include loose and creep. The destruction includes falling, slip, toppling, buckling and tensile. The unstability model of the imminent unstable high steep rock slop includes creeping-tensile, slip-pressuring -tensile, slip-tensile, curving-tensile, flowing-tensile, slip-curving, slip-tensile-shearing, stepped creeping-tensile, compressing-toppling-tensile, compressing-toppling-swaying shearing inflation, high stress-strong discharge deep tensile. In addition, the above pattern may combines in the time or the space, constitution combination pattern.There are two models as the right bank tensile slop of Pubugou hydroelectric station and Dr2 dangerous slop of Suofengying hydroelectric station to study the stability of the imminent unstable high steep rock slop. The result indicates:The epigenetic reformation is the main control factor to influence the stability of the right bank tensile slop of Pubugou hydroelectric station. From surface to deep of slop, the rock mass is loose area, toppling-tensile area, slip-tensile area or slip-pressurmg-tensile, deep tensile area. The distortion destruction is slip-falling of slop surface, shallow area toppling-tensile of slop, slip-tensile or slip-pressuring-tensile and deep tensile in weak discharge area.The stratum characteristic of Dr2 dangerous slop of Suofengying hydroelectric station is that upper part is hard (calcareous rock) and Lower part is soft (mudstone) . The crevasse and the Karst are many distributes, the behind tension fracture of slop is links up completely. There are small fault and weak intercalated layer in the mudstone. The possible unstable modal is collapsing-slip, along level slip, slip, toppling. The small change of environment condition can cause the Dr2 dangerous slop destruction.There are different distortion or destruction forms and models in different area of the right bank tensile slop of Pubugou hydroelectric station, so we must Takes the different processing technical to deal with them. The main wethod to deal with them is combined steel net-shotcrete and Frame, System -bolt, cable. The design parameter of cable is adjusted according to the actual situation of each area. But construction must satisfy the design. And we must complete the waterproof measure to aviod lead to unsteadily of the tensile slop by construction.The main method to deal with Dr2 dangerous slop of Suofengying hydroelectric station can simply summaried as "Wear hat on top", "belt the belt on waist","puts on the shoe on foot". After analysis, we adjust the design as following: cancel the anchoring adit on the top, expansion the area of pre-stressed anchoring, backfillthe crevasse by anchoring hole, adjust the area of anchoring and the angle of the blot in the middle area to effectively prevent the whole toppling or partial area toppling, anti-cuts plug replaces anchoring adit In base.