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| Numerical simulation of stability of slurry pressure-balanced shield tunneling considering seepage effect |
| HUANG Xin1, GU Guansi1, ZHANG Zixin1, LI Yun2
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1. Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China;
2. China Shipbuilding NDRI Engineering Co., Ltd., Shanghai 200063, China |
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Abstract In order to explore the impact of slurry pressure-balanced(SPB)shield tunneling on the ground response in high water pressure environment, this research systematically analyzed the ground stability subject to continuous excavation of SPB shield tunnel considering different overlying water heights and permeability coefficients by means of refined three-dimensional finite element numerical models. The evolutions of seepage and displacement fields at different stages of underwater shield tunneling, including shield placement, continuous excavation and stoppage, were obtained. It was found that for tunneling project in soft soil areas such as Shanghai, 40 m could be regarded as the threshold value distinguishing high and low water pressures. The seepage and deformation fields would show different evolution laws between cases with the water head higher than this threshold and cases with the water head lower than this threshold, and the difference could be more obvious in low permeable stratum. Seepage led to the change of ground's excess pore water pressure field, which further affected the ground displacement field. The largest deformation at the excavation face with seepage effect was about 1.4 times of that without seepage effect. The ground deformation under high water pressure condition was affected by the seepage effect, while the ground deformation under low water pressure condition was dominated by tunneling parameters, such as the grouting pressure. The aforementioned observations could provide useful guidance for the safety control of underwater shield tunneling.
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Received: 21 October 2021
Published: 20 June 2022
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