| The proposed Xulong hydropower project is located upon Jin Shajiang river, theborder of Deqin county in Yunnan province and Rong county in sichuan province. Thedam is concrete hyperbolic arch dam with213m. Xulong hydropower, high and steepon the Jin Shajiang river, is a huge project. The reservoir rock has experienced thelong-term geological processes, development of structural plane, and its rock massstructure characteristics is complex. The mutual transition of the structure may causedeformation of the slope instability, effecting on the project operation smoothly andsafety. After the excavation construction, high slope will be formed in the left bank ofthe dam with large-scale excavation, formation of the high and steep engineeringslope. Once the instability occurs, even the small block, it can cause seriousconsequences.Research on the Xulong hydropower project upon Jinsha river of the left bank,high and steep slope.On the basic geological conditions of dam site investigation andcharacteristics of the dam site area on the left bank slope rock mass structural plane,slope rock mass deformation and the rock mass quality classification, we classify itand research it systemically. Finally, numerical program FLAC, SASW are appliedand studied on overall stability and local block stability of the slope. The followingunderstandings and the conclusions have been mainly given.（1）The rock that outcrops in dam site area is mainly hoar fine grained granitein the indo-chinese epoch（γ5）, mesoproterozoic xiongsong group of three sections ofgray and black-dark green amphibolite schist（Pt2x3）and indosinian on mixedamphibolite schist metamorphic rock formed by mixing.The tectonic evolution in thestudy area has a long history and structure function is complex, the study on the leftbank is divided into four tectonic division:（2）Fault class structure in the study area are mainly Ⅲ, Ⅳ level, and largeangle intersect with the strike of the slope; Ⅱ level structural plane only developed oF1and F2; Through analysis the structure surface and structure surface of eachpartition, can be found that most structure surface of the dam site area is small angle intersection with the slope in jinsha river bank, the orientation of preferred structuralplane in each partition is different, and most of them in the steep dip Angle.（3）According to the signs of deformation damage investigation in differentpartition and elevation on the slope in the left bank of dam site area, combination ofrock mass structural features, analysing the deformation failure mode, put forwardfour kinds of rock mass deformation and failure mode of left bank.（4）Using the RMR and CSMR rock mass quality classification method to getthe Preliminary classification of rock mass quality on the left bank slope, and thencombined with on-site geological classification, considering the weight of variousmethods, comprehensive conclude the boundary of rock mass quality at all levels. Theclassification results show that rock mass along the river in zonal distribution on eachelevation, to the mountain are Ⅳ, Ⅲ, Ⅱ class rock, and the depth of Ⅳ class rockdeepen With the elevation rising. The results of CSMR rock mass qualityclassification method show that the stability of the slope play generally, only poorstability in the local place.（5）Applied two dimension finite difference numerical simulation softwareFLAC2D to simulate the overall stability of the slope, and the slope unloadingcharacteristics of rock mass is considered. The stability coefficient of left bank slopethat based on Mohr-coulomb criterion and the strength reduction method show thatslope is stable of stability as a whole. But the stability in surface layer of rock masselevation of rock mass in middle elevation of the slope is poor.Then use SASWnumerical simulation study program block on the local slope stability indicates thatthe slope be composed of a variety of block which consists of all kinds of structural plane,most blocks are stable, there is no large-scale bulk instability phenomenon, but theslopes surface location exist local small-scale instability block. Stability of the slopeafter the construction process should pay attention to the block of different parts, itshall take appropriate protective measures to prevent its instability works whennecessary. |
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