The Excavation and Treatment of Complex Karst Foundation of Aikou Reservoir Dam

摘要

The geological condition of Aikou reservoir dam is extremely complex and hence causes great difficulties for its excavation and treatment.Experiences of many experts specialized in karst geology and dam foundation treatment have been consulted to solve the worldwide problems that are caused by dam sites in limestone terrains.Its bedrock has intense limestone development. The linear corrosion rate of limestone amounts to 23.23%.It is found from primary excavation that dam foundation pit has severely undulation and its surface does not show traditional pattern.Based on detail geological investigation,dam foundation region is divided into three zones according to corrosion rate of limestone,i.e.Zone I of corrosion rock mass,Zone II of residual rock mass,Zone III of corrosion field with much silt fills.Dam foundation pit is divided into two areas of A and B for the design of excavation and treatment schemes in accord with specific requirement.Schemes of excavation and consolidation grouting for these two areas are introduced herein. Acoustic wave detection method is used to verify the grouting quality in Area A.Ground penetrating radar is used to investigate karst distribution in Area B in order to determine whether further treatment would be needed. At present,dam foundation excavation has been completed and passed through inspection and acceptance.Grouting tests have also been finished.Foundation grouting work is being carried out according to construction design.