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| Surrounding rock stress of rock pillar and its support control technology in super-large cross-section tunnel |
| LUO Bin1, YANG Hui1, LIU Ning2*, CAI Wei2
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1. The Fourth Engineering Co., Ltd., China Tiesiju Civil Engineering Group, Hefei 230041, Anhui, China;
2. School of Civil Engineering, Guizhou University, Guiyang 550025, Guizhou, China |
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Abstract In view of the characteristics of Chongqing Metro Station, such as large section, weak surrounding rock and great interference of cross construction, the mechanical properties and supporting measures of surrounding rock of super large section tunnel reserved middle rock column were studied. Based on Protodyakonov's theory, considering the influence of middle rock column, the calculation span of natural equilibrium arch was modified, and the calculation method of surrounding rock stress of reserved rock column was deduced, which was verified by actual case and numerical simulation. In order to improve the stability of surrounding rock, temporary steel support was added to the middle rock column, and the finite element software was used to simulate the support scheme and removal time of the reserved middle rock column. Considered the surrounding rock deformation, stress and site construction situation, the analysis showed that, temporary horizontal support adopted a layer of temporary horizontal bracing design.On the basis of meeting the deformation and stress of surrounding rock, it saved materials and reduces costs.It also improved the efficiency of construction. After the temporary support was removed after the invert construction, the vertical displacement of the vault of the tunnel, the horizontal displacement of the arch waist and the maximum vertical stress were the smallest when compared with the other two removal times.
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Received: 23 December 2020
Published: 20 March 2021
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