Investigation of RQD variation with scanline length and optimal threshold based on three-dimensional fracture network modeling  

作　　者：ZHANG Wen CHEN JianPing WANG Qing MA DongHe NIU CenCen ZHANG Wu 

机构地区：[1]College of Construction Engineering,Jilin University [2]China Water Northeastern Investigation,Design & Research Co.,Ltd. [3]College of Automotive Engineering,Jilin University

出　　处：《Chinese Science Bulletin》2013年第7期739-748,共10页

基　　金：supported by the National Natural Science Foundations of China (Grant Nos. 40872170,40902077 and 41072196);the Doctoral Program Foundation of Higher Education of China (Grant No. 20090061110054);2010 non-profit scientific special research funds of Ministry of Water Resources (Grant No. 201001008);Jilin University's 985 project (Grant No. 450070021107);the Graduate Innovation Fund of Jilin University (Grant No. 20121073)

摘　　要：Rock-quality designation(RQD) plays a significant role in rock mass analysis and is an important parameter in geotechnical and geological engineering.However,the RQD variation with scanline length has not yet been comprehensively considered in RQD.In this study,three-dimensional fracture network modeling was used to simulate actual rock mass,and numerous scanlines were set in the fracture network for investigation on RQD variation.Models and equations(i.e.,models A-A,N-N,and A-A-S,as well as the Priest-Hudson and Sen-Kazi equations) were summarized for the study.A corrected equation was proposed to eliminate the errors from using the Priest-Hudson and Sen-Kazi equations.In addition,inhomogeneous and anisotropic features were investigated,and the optimal thresholds for RQD calculation were determined,which varied with the study orientation and rock mass feature.When the inhomogeneity was studied in the x direction,the optimal threshold was found to be 4 m.When anisotropy was studied,the optimal threshold was found to be 3 m.Rock-quality designation （RQD） plays a significant role in rock mass analysis and is an important parameter in geotechnical and geological engineering. However, the RQD variation with scanline length has not yet been comprehensively considered in RQD. In this study, three-dimensional fracture network modeling was used to simulate actual rock mass, and numerous scan- lines were set in the fracture network for investigation on RQD variation. Models and equations （i.e., models A-A, N-N, and A-A-S, as well as the Priest-Hudson and Sen-Kazi equations） were summarized for the study. A corrected equation was pro- posed to eliminate the errors from using the Priest-Hudson and Sen-Kazi equations. In addition, inhomogeneous and aniso- tropic features were investigated, and the optimal thresholds for RQD calculation were determined, which varied with the study orientation and rock mass feature. When the inhomogeneity was studied in the x direction, the optimal threshold was found to be 4 m. When anisotropy was studied, the optimal threshold was found to be 3 m.

关 键 词：网络模型 最佳阈值 RQD 扫描线 长度 裂隙 三维 基础 

分 类 号：TU452[建筑科学—岩土工程] TP18[建筑科学—土工工程]