Abstract

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Title:: Relationships Among Rock Quality Designation, Wave Velocity and Permeability of Dam Foundation Rock Mass—Taking Ma’erdang Hydropower Station in Maqin Area of Qinghai, China as an Example

Author(s):: CHEN Kang-da; SONG Yan-hui; JU Guang-hong; RONG Juan; CHEN Zi-yu; 1. School of Geology Engineering and Geometics, Chang’an University, Xi’an 710054, Shaanxi, China; 2. Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education, Chang’an University, Xi’an 710054, Shaanxi, China; 3. Northwest Engineering Corporation Limited of Power China, Xi’an 710065, Shaanxi, China

Keywords:: dam foundation rock mass; quality classification; rock quality designation; permeability; hydropower station; wave velocity; depth

Abstract:: The quality classification indicators of dam foundation rock mass include the rock quality designation(RQD,Q), the velocity of the longitudinal wave (V), the permeability (ω), and so on. They have a certain relationship with each other and change with the depth (h). Based on the measured data of 6 boreholes on the riverbed dam foundation of Ma’erdang hydropower station in Maqin area of Qinghai, the variation of the above indices with depth and the relationships among them were studied. The results show that the RQD at the same depth is quite different, but increases in linear ribbon with the increase of depth as a whole, and the linear relationship for the upper and lower limits can be expressed by formulas Q=0.488h+67.886 and Q=0.309h+2.319, respectively; the permeability and depth have a good correlation, and the permeability decreases as a power function curve with the increase of depth, which is ω=1 329.192h^-1.599; the degree of fitting among RQD, permeability and depth is higher; the velocity of the longitudinal wave increases in linear ribbon with the increase of RQD, and the linear relationships for the upper and lower limits are V＝40.493Q+3 612.9 and V＝32.458Q+1 822.6, while the geometric mean of permeability tends to decrease and has a good correlation with the arithmetic mean of RQD, which is ω=6.378-3.708×10^-7Q^3.832.