大型贯穿层间错动带尺寸效应研究

Size effects of large penetrable bedding fault zone

白鹤滩水电站坝址区层间错动带具有规模宏大、贯穿性强、地质条件复杂等特点,对地下洞群稳定具有显著影响,由于层间错动带规模巨大,常规现场试验无法考虑波长起伏带来的影响,需引入尺寸效应分析。针对层间错动带力学参数取值开展了系统性研究工作,结合现场试验获取力学强度参数,通过引入数字近景摄影测量技术结合颗粒流数值方法对层间错动带进行尺寸效应分析。研究揭示了层间错动带的力学参数随粗糙度系数JRC、软弱充填厚度、尺寸效应变化的相应映射规律。在工程运用中,结合前期层间错动带研究成果,对白鹤滩尾调室穹顶进行形体优化,该实践方法可为其他工程提供相应参考。

The bedding fault zone in the dam site of Baihetan Hydropower Station is characterized by large scale,strong penetrability and complex geological conditions,which can control the underground caverns.Due to the large scale,the effects of wavelength fluctuation of the bedding fault zone cannot be considered accurately by normal field tests,and the size effect analysis needs to be introduced.A systematic study on the mechanical parameters of the bedding fault zone is carried out.Combining with the mechanical strength parameters obtained by the field tests,and the size effects of the bedding fault zone are analyzed by introducing the digital close-range photogrammetry technology and the particle flow numerical method.The mapping laws of the mechanical parameters of the bedding fault zone with joint roughness coefficient,soft filling thickness and size effects are revealed.In the engineering application,taking the advantages of the research results of bedding fault zone,the dome shape of tailrace surge chamber of Baihetan Hydropower Station is optimized.The method can provide a reference for other projects.