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Analysis and utilization of groundwater level monitoring data of underground water-sealed caverns |
ZHANG Yihu1, LIU Qian1*, GAO Ximin2, DING Changdong1, LUO Rong1, HU Wei1
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1. Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan 430010, Hubei, China; 2. Sinopec Pipeline Storage and Transportation Co., Ltd., Xuzhou 221008, Jiangsu, China |
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Abstract Based on groundwater level data of 35 monitoring boreholes from 2015 to 2020 obtained from a large-scale underground water-sealed cavern project, the characteristics and causes of the changes in the groundwater level were systematically analyzed. Taking the construction progress of each cavern unit and geological structure information obtained from previous survey into account, those monitoring data revealed the influence of underground cavern excavation and artificial water curtain system on groundwater level, and the possible risk areas of low water pressure. According to the corresponding relationship between the temporal changes of groundwater level and construction progress, the monitoring boreholes could be divided into three types: water level maintains relatively stable,water level declines when adjacent tunnels were excavated; water level declines far after the adjacent tunnels were excavated. Combined with the spatial distribution of boreholes and the construction progress of underground caverns, it could be found that the groundwater level in the overall study area declined after the excavation of the underground caverns. However, benefited by the artificial water curtain, groundwater level in most area maintained higher than the safe water level(-25 m). Affected by faults F2, F3 and joint fracture zones L4, L8, local groundwater level in the southwest was still far below the safe water level(-25 m)at the end of monitoring, and it indicated a risk of insufficient water sealing. It indicated that the dynamics of the groundwater level in the study area was closely related to the construction progress and quality of the underground caverns, and the systematic monitoring of the groundwater level and timely analysis and feedback were essential. It is urgent to compile a specification for the underground water monitoring of the water-sealed cavern to promote more systematic monitoring of groundwater and improve the construction efficiency of the project.
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Published: 10 April 2024
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