Evaluation of Excavation-Damaged Zone around Underground Tunnels by Theoretical Calculation and Field Test Methods

Ming Tao, Zhixian Hong, Kang Peng, Pengwei Sun, Mingyu Cao and Kun Du
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Ming Tao: School of Resources and Safety Engineering, Central South University, Changsha 410083, China
Zhixian Hong: School of Resources and Safety Engineering, Central South University, Changsha 410083, China
Kang Peng: College of Resources and Environmental Science, Chongqing University, Chongqing 400044, China
Pengwei Sun: Fankou Lead-zinc Mine, Shenzhen Zhongjin Lingnan Nonfemet Company Limited, Shaoguan 512325, China
Mingyu Cao: Fankou Lead-zinc Mine, Shenzhen Zhongjin Lingnan Nonfemet Company Limited, Shaoguan 512325, China
Kun Du: School of Resources and Safety Engineering, Central South University, Changsha 410083, China

Energies, 2019, vol. 12, issue 9, 1-18

Abstract: Excavation-damaged zones (EDZs) induced in underground mining and civil engineering potentially threaten tunnel safety and stability, and increase construction and support costs. In this paper, an investigation of the excavation damaged zone (EDZ) around roadways in Fankou lead-zinc mine in Guangzhou, China is performed by applying a seismic velocity method accompanied by SET-PLT-01 nonmetallic ultrasonic detector. Meanwhile, the in situ stress in the mining area was measured based on the stress relief method with the Swedish high-precision LUT system. The results indicate that the stress field is dominated by the maximum horizontal tectonic stress, and the extents of the EDZ on the roof-floor region are greater than that on the sidewall. In addition, both of the in situ stresses and EDZs show an increasing trend with an increase of depth. Analytical solutions of EDZ around circular openings in the brittle rock mass subjected to non-hydrostatic stress fields are presented in terms of the Mohr–Coulomb and generalized Hoek–Brown criteria, and validated by several cases mentioned above. The extents of EDZ solved by closed-form solutions were found to be in a great agreement with those obtained in the field. Finally, a series of parametric studies are conducted to investigate the effects of cohesion ( c ), friction angle ( φ ), geological strength index ( GSI ), m i , uniaxial compressive strength ( σ c ), and disturbance factor ( D ) on EDZ. It is shown that the effects of c , φ , GSI , and σ c are significant; however, more attention should be paid to consider the dynamic disturbances induced by mechanical drilling, blasting, and seismic waves in tunnel excavations or operations.

Keywords: excavation-damaged zone; closed-form solution; in situ stress; on-site measurement (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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