乌东德水电站大坝防渗帷幕成幕影响地质因素分析及处理措施

Geological Factors and Its Treatment Measures of Dams Anti-Seepage Grouting Curtain at Wudongde Hydropower Station

灌浆工程为地下隐蔽工程,其地质条件约束着实际的现场施工工艺,且不同地质条件对应不同的岩石属性,并将直接影响着防渗帷幕的优化设计,同时地质条件分析不足也将给整个灌浆工程带来很多不确定的风险。目前,地质条件预测在隧洞开挖过程中的研究较充分,但在灌浆工程中地质因素的研究较少。本文以乌东德水电站大坝防渗帷幕工程为例,分析了对防渗帷幕成幕有影响的岩溶、角砾岩、断层、岩层走向与帷幕走向大角度相交及长大结构面等地质因素,并针对不同地质因素的特点,提出了采取浓浆回填、灌浆孔加密加深、灌浆压力及浆材动态调整等处理措施,为帷幕灌浆工程优化提供了必要支持。

Grouting works are underground concealed works,and their geological conditions and different rock properties constrain the actual site construction technology,and influence the optimal design of dam anti-seepage curtain.The lack of analysis of geological conditions will bring a lot of uncertainty to the grouting engineering.Prediction of geological condition is well studied presently in tunnel excavation,but not the geological factors in grouting engineering.Based on the example of dam anti-seepage grouting curtain at the Wudongde hydropower station,the authors analyzed and studied the geological factors such as karst,breccia,fault,large structural plane,and the large intersection angle between the curtain and terrane strike.According to the characteristics of different geological factors,the authors put forward a series of treatment measures such as thick slurry backfilling,deepening and encryption of grouting hole,dynamic adjustment of grouting pressure and material.The study can reduce cognitive blindness of geological conditions,and provide necessary support for curtain grouting optimization.