水电站坝基河床地段岩体结构评价指标获取

The getting evaluating indicators of rock-mass structure in river-bed dam foundation of hydropower station

大型水电站坝基岩体评价中镶嵌结构(镶嵌碎裂结构)评价中存在着一定问题,分析处于地应力环境下紧密镶嵌结构岩体纵波速度高、完整性系数高、渗透性指标低、岩体变形模量高时,应从多指标、岩体力学参数上判别岩体质量等级,而不要仅以单一指标结构面间距小于30cm去判定其可利用性.着重介绍了河床覆盖地带结构面间距的间接分析获取方法:利用河床钻孔易于获得的岩体RQD、波速、渗透性等指标;通过建立岩体完整性系数Kv与RQD,Kv与结构面间距、渗透性指标q与岩体波速Vp之间的相关关系,从而得到河床地段岩体的结构面间距并用以评价其岩体结构类型.

The problem was introduced about rock-mass structure evaluation in dam foundation rock evaluation.In the stress station of high primary wave velocity,high integrity coefficient,low permeability index value and high rock-mass deformation modulus belonging to close mosaic structure rock-mass.The method to estimate quality index of rock mass was gotten from rock-mass mechanics parameter,not only depending on the space between discontinuities is lower than 30 cm.An indirect method was introduced that of analyzing the structure plane spacer in river-bed overlying area： the relation curve was establish between Kv and RQD,Kv and D,Lu and Vp by using of rock mass RQD and Vp and Lu coming from bore.At last,we achieve space between discontinuities in river-bed and evaluate rock-mass structure type.