裂隙岩体的渗透特性受控于裂隙的发育特征、连通特性和充填情况,并与岩体的地应力水平具有显著的相关性。基于裂隙岩体渗透性的影响因素,并考虑现有渗透系数估算模型的不足,利用钻孔压水试验和钻孔电视图像资料,建立考虑埋深(Z)、岩石质量指标(RQD)以及充填物指标(FSD)等3个指标的渗透系数估算ZRF模型,并应用到牙根二级水电站及其他工程区的渗透系数估算中。结果表明,与已有的渗透系数估算模型相比,ZRF模型较好地反映了岩体渗透性的影响因素,且模型参数物理意义明确,便于获取,对分析裂隙岩体渗透性具有一定的工程参考价值。
The permeability of fractured rock mass is essentially governed by its geometrical characteristics, connectivity and filling materials of fractures, which commonly displays a significant correlation with the magnitude of the geostress field. Due to the limitations of existing models for the prediction of permeability, a novel empirical model(called ZRF model) is established to estimate the permeability coefficient of fractured rock mass by considering various factors. Particularly, the proposed model represents the permeability coefficient as a function of three geological indexes, i.e. buried depth(Z), rock quality designation(RQD) and filling substance designation(FSD). These three parameters are easily calibrated with packer hydraulic test data and borehole acoustic television images. Then the proposed model has been successfully applied to predict the permeability coefficient of fractured rock mass at the site of Yagen-II Hydropower Station and two other sites at which the borehole data are available in the literature. Advantages of the ZRF model include more clear physical significance and easy parameterization in engineering practices over the other existing permeability estimation models. The results indicate that the proposed ZRF model provides a feasible tool for the estimation of permeability of fractured rock mass at various field conditions.