JRMGE / Vol 14 / Issue 4

Article

Stability analysis of surrounding rock mass in underground powerhouse considering damage effect of microfractures

Peiwei Xiao, Haoyu Mao, Bo Qian, Biao Li, Xingguo Yang, Nuwen Xu

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a State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, China
b Guodian Jinshajiang Xulong Hydropower Development Co., Ltd, Chengdu, 610041, China
c School of Geoscience and Technology, Southwest Petroleum University, Chengdu, 610500, China


2022, 14(4): 1115-1130. doi:10.1016/j.jrmge.2022.01.007


Received: 2021-10-11 / Revised: 2021-11-29 / Accepted: 2022-01-20 / Available online: 2022-03-16

2022, 14(4): 1115-1130.

doi:10.1016/j.jrmge.2022.01.007


Received: 2021-10-11

Revised: 2021-11-29

Accepted: 2022-01-20

Available online: 2022-03-16


Abstract:

A high-precision microseismic (MS) monitoring system was built to monitor surrounding rock microfractures in the underground powerhouse on the left bank of Shuangjiangkou Hydropower Station. The surrounding rock damage area with spatiotemporal clustering of MS activities was studied for qualitative analysis of the damage mechanism of surrounding rock microfractures, based on the source parameters of MS events. The surrounding rock microfracture scale characterized by the source radius of MS events was considered to establish the constitutive relation. MS information was imported into the model for numerical analysis using fast Lagrangian analysis of continuain 3 dimensions (FLAC3D). The results indicated that the numerical simulation results considering MS damage can better reflect the actual situation of the field. The surrounding rock microfractures mainly showed mixed failure characteristics. Shear failures appeared in localized areas while the fracture scale of sections from K0–33 m to K0–15 m on the vault was large. The deformation increment caused by microfracture damage in the shallow surrounding rock of the top arch accounted for 10%–13%, and the stress decrement in the surrounding rock caused by microfracture damage accounted for about 10%.

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Keywords: Underground powerhouse, Microseismic (MS) monitoring, Numerical modeling, Microfracture damage, Constitutive relation

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Peiwei Xiao, Haoyu Mao, Bo Qian, Biao Li, Xingguo Yang, Nuwen Xu, 2022. Stability analysis of surrounding rock mass in underground powerhouse considering damage effect of microfractures. J. Rock Mech. Geotech. Eng. 14 (4), 1115-1130.

Author(s) Information

Biao Li

✉️ libiaoscu@163.com

Dr. Biao Li is an associate professor in the School of Geoscience and Technology at Southwest Petroleum University. He gained his BSc degree in hydraulic and hydroelectric engineering and his PhD in geotechnical engineering from Sichuan University, China. His research interest focuses on stability evaluation of rock mass in underground engineering based on microseismic monitoring and analytical simulation, including excavation induced rock mass damage evaluation, deformation simulation, and disaster forecasting of underground caverns.