Study On Stability Evaluation And Support Methods Of The Kaergou High Steep Slope For Pubugou Hydroelectric Power Station

The kaergou slope of Pubugou Hydroelectric Power station has complex geological conditions. such as large excavation quantity,high height,roof,many free surfaces,developed weak structural planes, and a rapid excavation. Which must lead to stress redistribution, result from large-scale unloading deformation, there have been many part failure evidences, slope stability problems are prominent in construction time. Which are major geological engineering problems in Pubugou hydropower station construction. In order to ensure safety and Reinforcement'reasonableness validity and economical efficiency. this paper is based on a great lot of geological investigations of Kaergou high slope in Pubugou Hydroelectric Power Station, and attaches most important to the analysis of rock mass structure, the deformation of rock mass and the mechanism of deformation. The advanced theory and methods such as the Engineering Geology, Geotechnical Engineering, Rock mass Mechanics, Mathematical Statistics, and Numerical Simulation(3DEC) etc are used. and the supporting methods for blocks with SASW, which was based on Block Theory. Details and results are as follows:1. Based upon analysis of slop geological conditions, following with the slope excavation, the rock mass structure characteristic of the kaergou slope have been fully studied. These include the structural planes engineering geological classification; the all level structure planes engineering geological character and quality; and the rock mass structural engineering geological subzone. Then, the rock mass structure model of t??lope has been established. the III and IV-class structure of rock mass structure in the study area constitute the main framework of characteristics, III-class structure form the key block which controls the whole stability of the slope; III, IV-class structure form blocks which control the stability of the partial slope; V-class structures form superficial blocks.2. Based upon the failure traces of slope during excavation, considering the characteristic of rock mass structure, the mode of deformation is analyzed. The unload relaxation deformation has been formed in the shallow slope surface. It has the disturbed deformation controlled by the low-angle crack in part. And weathered and unloading rock mass.3. By 3DEC (DEM) numerical simulation, especially, considering III, IV structures'characters and comminuting features meanwhile, simulating the operation of rock mass structure during exaction. Including characteristics of displacement and stress distribution, the locations, size, deformation characteristics, Instability modes of deformation and failure Block. According to monitored dates make quantitative analysis for slop.4. According to the results of numerical simulation and the characteristic of rock mass structure on the slope which have been excavated step by step, make estimation of stability and dynamic design for slop; the stability calculation of key blocks through SASW software, According to calculation makes quantitative analysis for slop. An effective design was carried out.5. A simulation-validation for supporting measure was carried out by 3DEC, and it was obtained that deformation of the slope had been prevented, because of ??great effect of the anchor measure. The alignment between the simulation and monitoring information verified the feasibility of this method above.