Slope Stability Analysis And Countermeasures Of Intake Diversion Tunnel At The Left Bank Of Longtan Hydropower Station

Slope stability analysis is a hot topic of Geotechnical engineering. Especially in hydropower projects this phenomenon has become increasingly obvious. The reason of this lies in many aspects. With the increasing in the number and the scale of projects, we have to excave a variety of steep slope by force in the complex geological environmental conditions. All Steady-state of the slope projects is relevant to the success and security of constructions. It will play as a restrictive role in the field and have an effect on the feasibility and economical efficiency. Then to a large extent, it will affect the investment and construction efficiency.The slope of diversion tunnel on the left bank of Long tan is a kind of layered structure rock slope with anti-inclined rock. The geological conditions are quite poor and influenced by rock stability around the entrance of diversion tunnel. For this, instability conditions appeared. Whether the distortion of the slope will happen or not is to be know. In addition to this, the stability, construction safety and strengthening support program are the next step of the research.This paper focus on the qualitative analysis of main factors which affect the stability of Long tan hydropower project'slope by combining the geological conditions. Then the point of deformation and failure mechanisms and impact on slope are stated. On condition of all the geological factors, we established two computational geometry model which are before and after excavation of the lower diversion tunnel. Then we utilize the method of Fast Lagrangion Analysis of Continue to calculate and analyze the stability of the two kinds of conditions. The result revels that Intake Diversion Tunnel Slope is stable in the normal state. After the excavation of diversion tunnel,the rock on the roof is easy to collapse for instability with when it is affected by chasm and joint surface. Forced by the weight and rock mass stress, rock on the roof of the section of intake diversion tunnel will collapse,then it will affect the stability of the slope of the entrance. After the factor analysis and numerical simulation on slope stability,this paper gives a correct evaluation on the overall stability for the thorough understanding of the failure mechanism and possible damage patterns.With the result of slope stability analysis, we adopted a series of comprehensive management measures to the left bank of the slope in diversion tunnel in particular. Then the paper gives details on the methods and priorities of the construction. And what is worth mentioning is the excavation measure in diversion tunnel. The reasonable design slope treatment. Due to the reasonable program and considerate measure, the slope on the left bank is in the state of security and stability during constructing.