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| Anti-floating control technology for large-diameter shield tunnels of adjacent mountain |
| SUN Chao, ZHANG Guangwei*, DA Wuqiang, YU Zufeng
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| Guangdong Branch, China Railway Liuyuan Group Co., Ltd., Guangzhou 510700, Guangdong, China |
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Abstract Taking a rapid transformation project in Shenzhen as an example, a numerical simulation method was used to establish a large-diameter shield tunnel of adjacent Mountain 3D model. The deformation and stress characteristics of shield tunnel with shallow overburden soil under biased pressure were analyzed. Based on the experience of anti-floating construction in similar projects, the box reinforcement scheme, the loading scheme, the uplift pile-pipe rooft-anti-floating plate scheme and the prestressed anchor cable-anti-floating plate scheme were proposed to control the deformation of shield tunnels. The results showed that during the evolution process of shield tunnel from biased overburden to shallow overburden, the vertical deformation of the tunnel was greater than the horizontal deformation, and the deformation was significantly asymmetric due to the influence of biased loads. In terms of force characteristics, the bending moment and axial force of the segments exhibited an irregular dumbbell shape as a whole. As the Biased pressure weakens, the shape of the internal force gradually shifts from dumbbell shaped to left-right symmetrical. Under various anti-floating measures, from the distribution range and scale of the plastic zone, the development range of the plastic zone was the smallest under loading scheme, followed by the prestressed anchor cable-anti-floating plate scheme. In terms of controlling tunnel deformation, the loading scheme was significantly better than the prestressed anchor cable-anti-floating plate scheme, the uplift pile-pipe rooft-anti-floating plate scheme, and the box reinforcement scheme had the worst effect on controlling deformation. The better the deformation control effect, the greater the stress on the shield tunnel under this scheme. It was recommended to adopt a prestressed anchor cable-anti-floating plate scheme for this project.
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Received: 17 June 2024
Published: 08 January 2025
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