坡月水库坝基岩体抗剪强度取值分析

Analysis of shear strength value for dam foundation rock mass of Poyue Reservoir

坡月水库坝基岩体岩性主要为长石石英砂岩、泥岩粉砂岩和粉砂质页岩,它们的比例关系很大程度决定了坝基岩体的物理力学性能及抗剪强度指标,通过开挖后地质揭露及现场直剪试验成果对比,验证了设计中加权平均法所提出坝基岩体抗剪强度建议值的准确性。加权平均法应用到勘探工作量有限,现场试验缺乏等条件的中小型水利工程,尤其是重力坝坝区,提供坝基或较大面积建筑物地基岩体抗剪强度建议值中,具有节约、快速、准确性高等优点。

The dam foundation rock mass of Poyue Reservoir mainly consists of feldspathic quartz sandstone,mud⁃stone siltstone and silty shale.Their proportional relationship greatly determines the physical and mechanical prop⁃erties and shear strength index of dam foundation rock mass.The geological exposure after excavation was compared with the results of field direct shear test,which verify the accuracy of the dam foundation rock mass shear strength value recommended by weighted average method.For mid-and small-scale water conservancy projects and espe⁃cially the gravity dam area with limited survey work and short of field test conditions,weighted average method is able to recommend the foundation rock mass shear strength value for dam or large-area building with the advantag⁃es of less cost,rapid and high accuracy.