百色水利枢纽主要工程地质问题及施工处理

ENGINEERING GEOLOGICAL PROBLEMS AND PREVENTIVE MEASURES AT MULTIPURPOSE HYDROPOWER PROJECT IN BAISE,GUANGXI PROVINCE

百色水利枢纽属高坝大库,大坝及地下厂房主要洞室均建在地质条件复杂、厚度单薄的辉绿岩岩脉上,岩体完整性较差,其上、下盘接触蚀变带风化深,强度低,河床顺河发育有一条规模较大的F6断层,消力池地基极不均匀,风化夹层深厚,存在很多工程地质问题。在施工过程中,根据不同地质问题和建筑物对地基的要求,对上、下盘接触蚀变带采取了深层固结灌浆处理,对F6断层采取了深挖回填混凝土和加强帷幕灌浆处理,对消力池采取了加厚底板、固结灌浆和锚固处理,对地下厂房浅埋洞段和单薄岩墙所出现的塑性变形区采取了张拉锚杆和锚索加固。通过处理,整个工程运行正常,坝基及洞室变形、应力、渗压等观测资料均在设计范围之内。

The Multipurpose hydropower project in Baise of Guangxi province includes a huge reservoir and a high dam and many rock caverns for underground powerhouse. They are built on the thin diabase dike with complex geo- logical condition. The ground consists of poor integrity of the rock mass, deeply weathered rock in low - intensity of the upper and lower contact alteration zone. The foundation of stilling basin is uneven because weathered interface is buried deeply causing by a major fault developed in the diabase dike along the riverbed. So many geological problems were encountered. In the construction process, the different preventive measures were carried out to sta- blize the foundations of the buildings with different geological problems. Deep consolidation grouting was carried out to treat the upper and lower contact alteration zone. Deep cut and concrete backfill, strengthen consolidation grou- ting measures were carried out to treat the fault. Thickening the bottom layer, consolidation grouting and anchor processing were carried out to treat the foundation of the stilling basin. Tension bolt and cable reinforcement were carried out at the plastically deforming area of thin rock wall and the shallow buried section of the underground pow- erhouse. The project has been operating normally after the treatments. The observed data of the deformation of the dam foundation and the caverns, stress and osmotic pressure are within the design scope.