Mechanical response and stability analysis of rock mass in high geostress underground powerhouse caverns subjected to ex
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Mechanical response and stability analysis of rock mass in high geostress underground powerhouse caverns subjected to excavation LI Biao(李彪)1, DING Quan-fu(丁泉富)1, XU Nu-wen(徐奴文)2, LEI Yi-fan(雷艺繁)2, XU Yuan(许媛)3, ZHU Zhong-ping(朱忠平)4, LIU Jing-fei(刘金飞)5 1. School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China; 2. State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China; 3. Department of Engineering Science, University of Oxford, OX5 1PF, United Kingdom; 4. Sichuan Dadu River Shuangjiangkou Hydropower Development Co., Ltd., Maerkang 624099, China; 5. Power China Chengdu Engineering Co., Ltd., Chengdu 610072, China © Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract: To investigate the stability of rock mass in high geostress underground powerhouse caverns subjected to excavation, a microseismic (MS) monitoring system was established and the discrete element method (DEM)-based numerical simulation was carried out. The tempo-spatial damage characteristics of rock mass were analyzed. The evolution laws of MS source parameters during the formation of a rock collapse controlled by high geostress and geological structure were investigated. Additionally, a three-dimensional DEM model of the underground powerhouse caverns was built to reveal the deformation characteristics of rock mass. The results indicated that the MS events induced by excavation of high geostress underground powerhouse caverns occurred frequently. The large-stake crown of the main powerhouse was the main damage area. Prior to the rock collapse, the MS event count and accumulated energy release increased rapidly, while the apparent stress sharply increased and then decreased. The amount and proportion of shear and mixed MS events remarkably increased. The maximum displacement was generally located near the spandrel areas. The MS monitoring data and numerical simulation were in good agreement, which can provide significant references for damage evaluation and disaster forecasting in high geostress underground powerhouse caverns. Key words: high geostress; underground powerhouse caverns; microseismic monitoring; discrete element modelling; stability analysis Cite this article as: LI Biao, DING Quan-fu, XU Nu-wen, LEI Yi-fan, XU Yuan, ZHU Zhong-ping, LIU Jing-fei. Mechanical response and stability analysis of rock mass in high geostress underground powerhouse caverns subjected to excavation [J]. Journal of Central South University, 2020, 27(10): 2971−2984. DOI: https://doi.org/10.1007/ s11771-020-4506-8.
1 Introduction Most hydropower powerhouses in Southwest China are designed as underground type due to high
mountains and steep slopes. Affected by intense tectonic movements and great depths, many underground powerhouse caverns are constructed in high geostress zones. In addition, the complicated geological conditions and large-scale excavation-
Foundation item: Project(2017YFC
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