| Hydropower station is located in the Jinsha River downstream of Qiaojia County crane beach town, designed normal water level 765 m, the highest water level 825 m. Plant design capacity of 16000 MW, is China’s second, after the Three Gorges Dam, the world’s third giant hydropower station. I learned from July 2014 to enter the field work, and then repeatedly went to the scene. Field investigation that the normal water level, the Qiaojia county about 1/3 will be submerged. Qiaojia county area of about 700 m above sea level there are different levels of development of the sand layer, under normal water level will be at saturation. Since the formation Qiaojia county complex, staggered structure, blossoming, poor geological phenomenon is particularly developed, high intensity, high water level will be troubled Qiaojia overall slope stability key factors. Slope Stability study therefore has a very important value to the project.In this paper, we follow the "Mechanism of geological processes," and "quantitative analysis" thinking on Bank Structure, stability analysis:(1) Qiaojia County and the surrounding area slopes composed mainly of Quaternary Alluvial material from the bottom up are the Jinsha River alluvial sand and gravel stratum, hydrostatic accumulation layer, landslides and Jinsha River alluvial layer multi-level terraces; slope layer bit more stable, the overall tendency of the lower river, rivers vertical direction horizon level.(2) through on-site investigation, drilling, analysis Qiaojia County Bank Structure and development characteristics, and the resulting evolution of Qiaojia basin is divided into six phases: phase block area, local pull-apart rift stage, rift lake phase deposition phase, damming deposition phase, the demise of the damming stage and uneven lifting phase.(3) to sandy soil dynamic triaxial test as the core, the research Ⅸ degrees of intensity area sand strata liquefaction stress- strain values, the stress-strain relationship, arguments around qiaojia county state of saturated sand layer, the liquefied occur under the action of dynamic stress.(4) In addition, on the basis of the above test, the value of the parameters established by Qiaojia two-dimensional cross-sectional, and 3D models. After the completion of the reservoir, the water level change is bound to affect change in the water table slope slope body, the whole process of seepage slope stability will also change. Rise and fall of the water level in the process of groundwater level simulation analysis and calculation of the various processes in real-time stability of the slope. From the site survey, signs of stability and deformation analysis, the natural state Qiaojia county as a whole is in a stable state, and not in the water storage state, but also in a stable state. The three-dimensional numerical simulation study area maximum and minimum principal stress is mainly distributed in the vicinity of the steepness and phase fault zone. Overall analysis shows that the study area is currently in a stable condition, but under extreme seismic + impoundment working conditions, the surface liquefaction situation that may arise, leading to local slope instability, so deal with the study area given high priority in the reservoir water during operation closely monitored, observing the development trend of the deformation. |
PDF Full Text Request