Soil Engineering and Foundation

Soil Engineering and Foundation ›› 2025, Vol. 39 ›› Issue (3): 424-427.

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Discussions on Simplified Estimation Method of Basic Quality Index BQ Value of Rock Mass

WANG Zhenzhong1, ZHANG Li2, SUN Zhen1, WANG Lei3, ZHAO Qingzheng4， ZHU Zeqi5   

  1. (1.China Railway Development & Investment Co. Ltd., Qingdao 266034；2.Shanxi Lihuo Expressway Co. Ltd, Changzhi 046000；3.China Railway Tunnel Stock Co. Ltd, Zhengzhou 450001；4.China Railway Third Bureau Group No.6 Engineering Co. Ltd., Jinzhong 030600；5.Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071)
  • Received:2023-06-04 Revised:2023-06-14 Online:2025-06-30 Published:2025-08-05

Abstract: In the classification of rock mass quality based on BQ value, a lot of in-situ and laboratory testing work are often required. For long-distance rock tunnels, the related work is more complicated and difficult. The Taiyueshan Tunnel in Shanxi Province on the Changzhi Yan’an connecting line (G2211) of the Qinglan National Expressway is presented in this paper. Based on the existing rock mass test data of the Taiyueshan Rock Tunnel, a simplified calculation method of BQ value is proposed by studying the relationship between rock saturated uniaxial compressive strength Rc and rock integrity index Kv. Comparing this method with the original BQ value estimation method, it is found that the two methods are basically consistent. The simplified estimation method of BQ value has a good engineering applicability and can greatly reduce the in-situ test workload and the influence of subjective experience.

Key words: Rock Mass Classification, BQ Value, Estimation method, Saturated Uniaxial Compressive Strength, Rock Mass Integrity Index

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