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| Determination of weighted joint density(wJd) from inclined surface observations in rock masses |
| LIU Ming1，2，HUANG Runqiu1，YAN Ming1，LIN Feng1 |
(1. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection，Chengdu University of Technology，Chengdu，Sichuan 610059，China；2. Faculty of Geosciences and Environmental Engineering，Southwest Jiaotong University，
Chengdu，Sichuan 610031，China) |
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Abstract The weighted joint density(wJd) method was revisited and modified by considering the angle between the structural plane and the observation surface，which offered better information for characterizing the degree of joints in the rock mass. The accuracy of the method relies on the measurement of the angle between each joint and the observation surface，and in particular，for the inclined surfaces. A modified wJd method was derived for the inclined surfaces based on the original form of wJd method calculated from the geometrical relationship between the angels of pitch/dip and strike. The accuracy of the modified method was validated in practice and discussed in the paper. Validation was performed in light of the dataset obtained from three case studies to calculate and compare the values of wJd with different sampling methods，including the global grid method，the overlying gird method，and the elementary unit method. The results were compared with the corresponding values obtained using the volumetric joint count(Jv) method，and the elementary unit method(1 m×1 m) yielded the most optimal outcome and reduced the bias induced by the offset of traces. The results demonstrate that the modified wJd method provides a novel and reliable means of evaluating rock mass quality for inclined surfaces.
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2016, Vol. 35 
