The Research On Engineering Flexibility Of Longpan Dam Region Of Tiger Leaping Gorge Hydroelectric In Jingsha River

Tiger Leaping Gorge hydroelectric locate in the boundary between LiJiang County and ZhongDian County of the northwestard of YunNan province ,stored plenty of waterpower resource.It was the most ideal exploiture place in JinSha River.Information obtained by studying on spot and data collecting indicated that the complicated geological environment would influence on the stability of the rock mass in the dam region. Because of those, the paper systems analysis the complicated geological environment, the character of rock mass's stress field and the stability of landslide on the right bank ,in addition, the paper also deeply studied the geological engineering problem after the dam was builded in order to provide science datum for engineering decision,and elicited several conclusion:(1) The character of rock mass's stress-strain and new structure stress fieldrfrom the middle of Q3 to today ,the direction of the maximal principal stress has already changed to the SN, the stress-strain action and three direction of stress have been changed from "potential positive break "to "potential slide".(2) The structure condition of the earthquake happened: Ms≥6.0 earthquake frequently happened several special structure place as follows: the intervein or the intersect of two deep and large rupture that their activity were very strong,the east of Yulong-Jiuzihai rupture and YuLong snow mountain rupture.(3) The mechanical analysis of the earthquake happening about Yulong snow mountain.(4) Determinant of the landslide on the right bank: determinant: the landslide was discovered by geological studying, boring etc..(5)Conclusion was obtained by the analyzing and studying the mechanics environment of the rock mass and the landslide on right bank: according to the analysis ,the present direction of the maximal principle stress was consistent with the present tectonic stress field ,The value of the principle stress increased or reduced in special place, and there was tensile stress region at the 2000m or above it on the left bank, the accumulate and adjustment was very limited in 200 years, the calculated result of the landslide indicated that the landslide on the right bank was stable under the various conditions.(6) Conclusion was obtained by the analyzing the mechanics environment and the stability of the lanslide on the right bank after the dam built: the value of the rock mass stress increased andthe tensile stress region obviously reduced, the direction of the principal stress was unchangeable the dam and the landslide were stable under the dangerous condition ( the reservoir and at the same time the earthquake was VIII),But when the water lever suddenly fell and did not think of other force , safe factor evidently reduced, the dam and the landslide will be destroyed under the most dangerous condition (the water lever suddenly fell and at the same time the earthquake was VI); the stability of the landslide will be destroyed by the horizontal thrust under the most dangerous condition or ; The physical and mechanical parameter will be reduced due to long period filter, the landslide will be destroyed too.