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Stability evaluation and faults influence analysis of water-sealed caverns during construction |
FU Changbo1, HONG Chenghua2, WANG Zhechao2, WANG Pengyu2, LI Wei2
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1. CNOOC Petrochemical Engineering Co., Ltd., Qingdao 266101, Shandong, China; 2. Institute of Deep Engineering and Intelligent Technology, Northeastern University, Shenyang 110819, Liaoning, China |
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Abstract The stability of surrounding rock within an underground water-sealed cavern project was investigated to examine the stability of surrounding rock under the intersection of multiple faults and underground caverns. The Hoek-Brown modified rock mass physical-mechanical parameters were utilized, and the Mohr-Coulomb model in the FLAC3D software was employed as a constitutive model. The results showed that the sidewall displacement of the main chamber gradually increased with the progress of the excavation stage. After the entire section was completely excavated, the lateral displacement of the primary cavern's sidewall generally surpassed that of both its vault and bottom plate. Stress concentration and plastic deformation were observed in the sidewalls of most caverns, as well as in the top sections of select caverns. In caverns adjacent to, but not intersecting with faults, unstable rock mass areas were formed between the cavern and the fault, where the rock mass tended to slide into the cavern, resulting in significant displacement. In caverns directly intersecting with faults, the unstable rock mass areas disappeared and a similar displacement pattern was observed as that without faults. Stress release in the surrounding rock was induced by the fault and significant plastic deformation of adjacent rock near the cavern was resulted. In the construction process of an underground water-sealed cavern, the position of the direct fault crossing needs to be monitored, and attention should be paid to its anterior and posterior positions.
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Published: 10 April 2024
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