Rock and Soil Mechanics ›› 2023, Vol. 44 ›› Issue (9): 2545-2554.doi: 10.16285/j.rsm.2022.6549

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Experimental study on shear properties of fault gouge with different mineral compositions

XIE Li-huan1, 2, LIU He-juan1, 2, BAN Sheng-nan1, 2, MAO Hai-jun1, 2, XIA De-bin1, 2, SONG Yu-jia1, 2, TONG Rong-chen1, 2, YING Qi-qi1, 2   

  1. 1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Science, Wuhan, Hubei 430071, China 2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Online:2023-09-11 Published:2023-12-17
  • Contact: LIU He-juan, female, bore in 1983, PhD, Professor, PhD supervisor, research interests: the sealing theory and evaluation technology of geologic body in energy underground storage and CCUS engineering. E-mail: hjliu@whrsm.ac.cn E-mail:xielihuan20@mails.ucas.ac.cn
  • About author: XIE Li-huan, male, bore in 1998, Master, research interests: fault activation mechanism of underground gas storage.
  • Supported by:
    CAS Pioneer Hundred Talents Program (Y826031C01) and the National Natural Science Foundation (U22A20166).

Abstract: The strength parameters of fault gouge is significant for the fault sealing of underground gas storage. In this paper, direct shear tests are performed for fault gouge composed of different contents of kaolinite(K), montmorillonite(M) and quartz(Q), thus obtaining the shear strength parameters (cohesion c and internal friction angle ) of various types of fault gouge. The results reveal that: (1) the cohesion of fault gouge is positively correlated with the content of montmorillonite and negatively correlated with the content of quartz. The cohesion of fault gouge specimens with high content of montmorillonite (≥40%) is positively correlated with the content of kaolinite; (2) The internal friction angle of fault gouge is negatively correlated with the content of montmorillonite and positively correlated with the content of kaolinite; (3) The cohesion of fault gouge is positively correlated with the plasticity index IP, while the internal friction angle is negatively correlated with the plasticity index IP; (4) The predicted shear strength parameters of fault gouge obtained by statistical methods match well with the experimental results, indicating that statistical method is feasible in predicting the shear strength of fault gouge.

Key words: fault gouge, shear properties, cohesion, internal friction angle, mineral composition