里底水电站千枚岩坝基开挖质量控制及效果评价

Quality Control and Effect Evaluation of the Excavation of Phyllite Dam Foundation in Lidi Hydropower Station

里底水电站右副坝、底孔坝段、厂房坝段基础基岩主要为绢云母石英千枚岩夹少量变质砂岩及微晶片岩,岩层走向与坡向小角度斜交或近平行,坡面倾向同岩层倾向相反,基本属于纵向谷的逆向坡。顺层结构面发育(占统计条数90%以上),坝基开挖质量控制难度较大[1]。为保证坝基建基面施工质量,施工中通过开展现场工艺试验,不断总结和优化参数,动态控制爆破参数,改善施工工艺,形成了一套可操作性强、行之有效的施工方法。

The foundation bedrocks of the right auxiliary dam,the bottom hole dam section and the powerhouse dam section of Lidi Hydropower Station are mainly sericite quartz phyllite with a few metamorphic sandstone and microcrystalline rocks.The rock strata strike is obliquely or nearly parallel to the small slope angle,and the slope inclination is opposite to that of the rock strata,basically belongs to the reverse slope of the longitudinal valley.With the development of bedding structural plane(accounting for more than 90%of the statistical items),it is difficult to control the quality of dam foundation excavation.In order to guarantee the construction quality of dam foundation surface,a set of operable and effective construction methods have been formed during construction by carrying out field process tests,continuously summarizing and optimizing parameters,dynamically controlling blasting parameters and improving construction technology.