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Study on Optimum Excavation Height of Middle Bench in an Underground Cavern Based on Q System Design
(1 Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education, Southwest Jiaotong University, Chengdu 610031;2 China Railway Second Bureau Engineering Co., Ltd., Chengdu 610091)
Abstract In order to determine the optimum excavation height of middle bench in an underground cavern based on Q system design, taking the large underground oil storage cavern in Jinzhou for example, the Q value method was compared with other rock mass classification methods and the mathematic function relationship was established among the Q value, RMR value and BQ value on basis of the statistics of Q value, RMR value and BQ value at site.The effect of different bench heights on excavation deformation and stress, and the distribution scope of the maximum values under different rock mass conditions were analyzed by numerical simulation and site monitoring. The research results show that the vertical and horizontal displacements increase with a decrease of Q value under the same height of middle bench; the height of middle bench has little effect on vertical and horizontal displacements in condition of same Q value; different heights of middle bench under different Q values have significant effect on the maximum horizontal and vertical stresses and the locations. Reasonable heights of middle bench were proposed considering the maximum stress and the location.
Abstract：
In order to determine the optimum excavation height of middle bench in an underground cavern based on Q system design, taking the large underground oil storage cavern in Jinzhou for example, the Q value method was compared with other rock mass classification methods and the mathematic function relationship was established among the Q value, RMR value and BQ value on basis of the statistics of Q value, RMR value and BQ value at site.The effect of different bench heights on excavation deformation and stress, and the distribution scope of the maximum values under different rock mass conditions were analyzed by numerical simulation and site monitoring. The research results show that the vertical and horizontal displacements increase with a decrease of Q value under the same height of middle bench; the height of middle bench has little effect on vertical and horizontal displacements in condition of same Q value; different heights of middle bench under different Q values have significant effect on the maximum horizontal and vertical stresses and the locations. Reasonable heights of middle bench were proposed considering the maximum stress and the location.
ZHANG Heng1 ZHU Yimo1 LIN Fang1 CHEN Shougen1 YANG Jiasong2
.Study on Optimum Excavation Height of Middle Bench in an Underground Cavern Based on Q System Design[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(4): 30-37
2019, Vol. 56 