Stability Evaluating Of Soil Bank-slope From Estuary To Gaoyang In Xiangxi River Valley

Xiangxi River, as the one of branch of Yangtze River, lies in head-section of the Three Gorges. With the first and second impound water in the three gorges reservoir, the water line is raise rapidly and plenty of rock and soil of both sides shore is submerged, which not only depress the sheer strength of rock and soil, but also destroy the mechanics balance of inner shore, consequently induce old landslide renewed and new landslide occurrence.The author carry on the particular investigation on height less at 450 meters of bayou-Gaoyang right-side bank of Xiangxi River, The topic study the all bank-slope's character and process its sortation based on those shape, distributing area, configuration and development and so on. Author makes out the suggestion value of phy-mechanics parameter of rock and soil for adapting to the work region, which based on summarize former work-fruit, examination in locale and laboratory, and consider the land character in the region such as its genesis, component, configuration and structure. During the investigation and study, we use multi monitoring analysis method, including deep drill-hole inclination survey (the type is cx-03), total station instrument and extensometer, in Baijiabao and Genjiaping landslide which the deformation grade is higher when the reservoir impounds water. Sequentially the paper studies the mechanism for failure of bank-slope under the condition of rainfall and impounds water.The Baijiabao is typical in all kinds of landslides of Xiangxi River valley which the old landslide is renewed. So the paper carries on the stability analysis under the condition of natural and impounds water respectively by the professional software FLAC^3d, and fitting result is perfect between the actual monitoring point and the simulate calculation point. On another side, the paper put up the stability evaluation on the whole reservoir bank of bayou-Gaoyang region of Xiangxi River by qualitative analysis method.The paper acquires following study result:(1) The paper makes certain the distortion model of shore-slope in work region. The uppermost distortion model is slippage among the model of erode, collapse backpedal and slippage. Rainfall and impound water is most key induce factor to the slide instability in the region.(2) The paper analyzes the distortion mechanism of Baijiabao landslide and Genjiaping landslide. The result shows Genjiaping is fleet-layer landslide and no form distinct slide surface. As to Baijiabao, the investigation shows it form distinct slide surface but no run-through when the water level of impound is up to 139 meters, and the style of deformation mechanism is integer process, and then the landslide is in the phase of creeping slide.(3) The paper finished numerical simulate in Baijiabao landslide. The result shows the water level is 156～175 meters when its slide surface is run-through. So the probability to slip of the landslide is higher when the water level of the three gorges reservoir impounds is to 175 meters.