Studies On Stability On The Condition Of Reservoir In Front Of Dam Of The Toppling Deformation Body Of Nujiangqiao Hydropower Station On The Nu River

The Nujiangqiao hydropower station is located in the upstream of the Nu River of Tibet province. By the valley cutting action, this area is formed a mountain canyon geomorphology. Toppling slope is situated on upstream of the dam 768 meters on the left bank. The Toppling slope scale is large, near the dam and develops deformation and destruction strongly. When the dam impounds, the slope will be damaged. Therefore, the deformation of slope stability and the stability after the reservoirs has become an urgent problem at this stage.Following the basic idea that the field research- analysis of engineering geological conditions- dumping deformation of understanding- Deformation Mechanism- slope seepage field analysis- quantitative evaluation of stability, the paper studies the space form, deformation and failure characteristics, influencing factors, and deformation mechanisms of the toppling slope engineering environment geological conditions of toppling slope and structural characteristics of rock slope, and it analyses the changes of seepage field and seepage field and stress field coupling characteristics under the conditions of reservoirs, On the basis of above, alculates the stability, The major achievement and knowledge are as follows:(1)The toppling slope strata are lower carboniferous Cuo rong gou Fabric. The main lithology is thin-medium and gray-black marble with schist. Normal attitude of stratum is N12~38°E/SE∠68°~85°, after dumping strata dip is less than 60 degrees. The slope belongs to the large dump toppling deformation body and its slope angle is steep, and it’s angle deeper in upper but slow in down. The average slope is 40 degrees According to According to the differences in topography and deformation and failure characteristics of the exploration and field investigation, the slope can be divided into three zones.(2)Class II, IV level, V-level structural surface is well developed, the rocks was bend violently affected by the weathering and unloading as well as the role of the gravitational field, external and deep of slope showed varying degrees of dumping bending, and the current overall distortion is not obvious. By the dip inside the dump, the maximum tensile tensor in layer, slope and unloading weathered adit longitudinal wave velocity characteristics and other aspects, the rock mass is divided into strong and weak dumped two levels.(3)The main factors of slope toppling deformation have the topography, structural features of the slope, the anti-dumping thin-middle in the thick layer of rock, and cutting down of the valley. The slope experienced initial deformation, the initial micro-bending and bending- breaking stage three processes, and its deformation and failure mechanisms was considered dumping – bend and bend- breaking type.(4)The paper uses the Seep software to calculate non-saturated water seepage under the conditions of reservoirs, and analyses the changes of infiltration various of each line and pore water pressure water, and explore the effects about water level rising rate changes to the seepage. Based on fluid-solid coupling theory, for the 1zone example, studys changes of seepage and stress field were coupled in consideration of the impact.(5)Shallow and deep stability calculation results show that the natural state district are in a steady state not only1,2 area but also 3 area. The stability first decreases and then increases on the condition of increasing water level, and higher speed will creases greater the impact on the stability; Stability about Shallow deformation body in 3 zone appears a steady stable- less stable- basically stable state, 2 area and 1 area are relatively stable, and does not damage along shallow deformation slip. The results of FLAC3 D display that toe the 1 area are unstable, and 2 area localized collapse destroyed focuses on the upper body. After storage, the deformation of the slope will increase, but not the magnitude, zone 1 will have the smaller the amount of deformation, shear strain of 2 area and 3 area will have the trend through the deformable body and may be unstable.