| Yebatan Hydropower Station in Sichuan Province and Tibet AutonomousRegion is located in the border river, in the middle of the Jinsha River upstream,upstream reservoir backwater to the Baltic station, downstream and link to LAWAhydropower. Dam Area steep terrain is alpine "V" shaped canyon, but to stress highearthquake less developed. Geological conditions of the left dam area is complex,the distribution of rock mass difference is obvious.In this Article, the left dam area of Jinsha River Yebatan Hydropower Stationas research object, look through the surface structure of rock dam area and theexposed surface of the large-scale structure surface conditions; records the left damarea oflow, medium and high three high-rise total14geological conditions adits;adit conducted individually and acoustic testing laboratories; and focus on thespecimen within the adit site point load test and indoor uniaxial compressionexperiments. On the basis of research on the structure of the left rock dam area willbe division and rock quality evaluation, mainly achieved the following results:(1) the left dam area contains two large-scale surface structures controlling Ⅱlevel (F1, F2), the main structure of the surface type dam area for the developmentof structural surface grade Ⅲ,Ⅳ,Ⅴgrade structural surface is mainlyfissures,distribution is more dispersed, and most of the structure faces a steep dipand development at all levels, about65-75°.(2) the left dam area weathering unloading obvious, which mainly weatheredweathering weak, there is not have a large area of strong weathering or fullweathered rock weathering in the horizontal direction from outside to inside fromstrong to weak, descending from strong to weak, Weak weathering thickness of cap,the lower limit of the basic weak weathered unloading by weak control; unloadingprevalent in the dam area, and presented with lower elevation and horizontal andvertical depth increases, unloading strength gradually weakened, and in mostregions of deep unloading visible phenomenon mainly in the depth of90-110m.(3) consider the impact of the structure of the left dam areaand weatheringunloading conditions, combined with on-site survey results, summarize the main left dam area of rock structure and layered block-based, chunky, followed by blocklike small and scattered body shaped rock structure types are rare.(4) According to the typical characteristics of rock the left dam area, andidentified the main evaluation factors RMR rock quality evaluation method for rockstrength, structure, surface condition, joint spacing, groundwater conditions andstress conditions. The integrity of the rock mass coefficient BQ method forevaluation of rock strength and sonic test reactions. According to the actualsituation of the left dam area and establish two methods corresponding rock massclassification scheme.(5) methods for RMR BQ evaluation method and the results were analyzed:two different evaluation results of the evaluation system is basically the same,determined differences between regions of the rock quality level. on this basis, theoverall rock dam area on the left body is rock-level divisions: Ⅲgrade rock of theleft dam area of the main components, mainly at the level of the region after the20m-40m depth; slope surface is mainly Ⅳ, Ⅴgrade rock.(6) Based on divisions of the left dam area of the rock mass, using of thestability of the construction of the dam abutment of FLAC3D software simulation.In the excavation conditions, the left dam area of Yebatan in a relatively stable state,deformation and stress does not cause a greater impact on the construction of thedam area pre-and post-operation, but it should be noted that extends longer andscale larger impact at the major types of structural surface. |
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