筱溪水电站复杂坝基处理

Treatment for Complex Dam Foundation of Xiaoxi Hydropower Station

筱溪水电站坝基受顺河向区域性大断层和两个背斜构造以及数条次生断层的影响,河床中部破碎区宽度达180m,且地层岩性多变,力学强度极不均一。通过大量的现场岩基试验、原位固结灌浆和帷幕灌浆试验、声波检测对比、锚筋桩抗拔与抗剪的试验研究,结构体型优化和施工工艺探索,以及有限元计算分析,最终采用并实施了体型调整、坝段间并缝与塑性链接、坝基灌浆加固和锚筋桩抗剪、防渗帷幕加强和坝基渗水抽排等综合性的地基处理措施,经济有效地解决了坝基抗滑稳定、不均匀沉降变形和渗透变形问题,取得了区域大断层上筑坝的成功经验。

Dam foundation of Xiaoxi Hydropower Station is affected by regional fault along river flow direction,two arch structures and several secondary faults.Fractured zone in the middle of riverbed has the width of 180 m,and the formation lithology is varied and extremely uneven in mechanical strength.By lots of field rock formation tests,as well tests and studies in situ consolidation grouting and curtain grouting,acoustic detection and comparison,pulling test and shear-resisting test of anchor piles,optimization of structure shape and construction technology,and finite element calculation and back analysis have been performed.Comprehensive foundation treatment measures,such as shape adjustment,butted seam and plastic link between dam sections,dam foundation grouting and reinforcement,anchor piles shear-resisting,reinforcement of impervious curtain,and seepage water pumping-out,etc.are adopted or applied in the end.Economically and availably treated sliding stability,uneven settlement,seepage deformation of dam foundation.It is a successful experience in building dam on large regional fault.