三峡坝基灌浆施工主要技术问题及解决措

三峡坝基灌浆施工因地质条件和技术要求等原因有多个技术问题需要解决,其中有6个问题较为突出,即基岩微细裂隙的灌浆、断层加固、帷幕钻孔涌水灌浆、帷幕孔口段灌浆压力的提高、浅层化学灌浆和找平混凝土封闭法固结灌浆等,通过试验研究,分别采用了湿磨细水泥浆材灌浆、复合灌浆、浓浆+稀浆方式待凝、提高孔口段灌浆压力到幕前水头的2倍、采用丙烯酸盐灌浆和改进阻塞方式、加强抬动观测防止抬动等措施,并以三峡二、三期工程的大坝基础固结灌浆和帷幕灌浆施工技术为例,介绍了具体措施和施工效果。

Main technical problems in dam foundation grouting construction of Three-Gorges Project and measures for their treatment

Owing to the complicated geological conditions and high requirement of techniques in dam foundation grouting construction of the Three-Gorges Project,there are some technical problems needed to be solved,mainly including minute fissure grouting in foundation rock,fault reinforcement,curtain grouting method suitable for water rushing during boring,enhancement of curtain grouting pressure at orifices,shallow layer chemical grouting,closed consolidation grouting of concrete,and so on.Based on experimental study,some measures were taken,such as wet milling cement grouting,composite grouting,dense grouting and thin grouting combined mode for concrete coagulation,enhancement of curtain grouting pressure twice at orifices,adoption of chemical curtain,improvement of blocking mode,strengthening of raising observation,etc..With the application of the solidification grouting and curtain grouting techniques to dam foundation construction at the second and third stages of the Three-Gorges Project taken as an example,the effects of above techniques were introduced.