Stability Evaluation Of The Slope Above The Top Of The Dam On The Right Bank Of Jinping I Hydropower

At present, with the development of our country economy, the demand for energy is increasing. In order to solve the problem of energy crisis,the government continually establish large water conservancy and hydropower projects in southwest China with the region of reserves. However, due to the southwest topography, and hydropower engineering constructs in the mountains and valleys,the stability problem of high slope is the key of problem of construction.The slope above the top of the dam on the right bank of Jinping I Hydropower Station is located at more than 1885m elevation, its stability involves the safety of the buildings in the hub area. This article mainly studys the slope stability. By analyzing a large number of survey data, combined with slope failure phenomena and monitoring information, analyzes the slope instability mode. Using numerical simulation methods and limit equilibrium method, calculate and analyzes the slope overall and partial stability. And the results of the study as follows:1) on the basis of comprehensive analysis of engineering geological conditions of the right bank slope, combining slope excavation to study the structural characteristics of rock mass of the right bank slope above the top of the dam, Mainly including the rock lithological characteristics, rock mass discontinuity characteristics (including the inter-layer extrusion offset zone, faults, joint fissure, unloaded fissure, etc.), and to establish a structural model of rock mass.2) From the damaged phenomenon of rock mass of slope, based on structural model of rock mass of slope, combined with monitoring information to analyzes the slope failure mode. Studies show that high slope excavated may be mainly occurred with dislocation Planar slip and ladder-like slip failure along the inter-layer extrusion. The destruction association is as follows: in the slope above the 1885 elevation platform includes cable platform slope, the main development faults fRL3 and the inter-layer extrusion offset zone gRL13 or gRL8, gRL9, gRL7 gRL10, etc. gRL13 or gRL8, gRL9, gRL7 gRL10, etc as the bottom sliding surface, fRL3 for edge cracking, Sliding failure plane combination may occur there. In high-line concrete system slope, the main development faults f13 and the inter-layer extrusion offset zone gh13 or gh10, gh14, gh17 gh5, etc. gh13 or gh10, gh14, gh17 gh5, etc as the bottom sliding surface, fh13 for edge cracking, Sliding failure plane combination may occur there.3) Based on the geological prototype slope,calculates the slope stability by using numerical simulation in the excavation or supporting conditions. The results show that the excavated slope rebound effect arising from unloading. Displacement occurred mainly in the vertical direction. In faults and inter-layer extrusion offset zones developed area , the displacement of excavate slope to the valley is more obvious. Fault belt and the surrounding rock mass occurred plastic deformation. After supporting, the development of the majority area significantly reduced, and tend to converge. Only in the Mid-stream and upstream slope of the Banhelou platform to Shaifen platform slope, of high-line concrete system slope, there is the clear displacement to the valley direction.4) Using the limit equilibrium method, quantitatively analyzes the slope stability in the excavation or supporting conditions. On the base of slope failure model, combined with numerical simulation results, select representative profiles for the calculation of limit equilibrium. On the results of analysis and calculation, with layers of extrusion rupture zone as the slope instability, and other common stability coefficient while more than 1, but safety margin is not high.After the supporting, in deceloped area of fault f13 and inter-layer extrusion offset zone gh13 of the Banhelou to Shaifen platform slope of the high-line concrete system slope, although the stability coefficient is more than 1, but its safety margin is relatively low on the condition of earthquake + rains. Therefore should further study the safety During the operation period. The stability coefficient of the rest of the rock mass with unfavorable structure is more than 1, and higher safety margin.