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Analysis of Ground Settlement Induced by Shield Tunnel Construction in a Soft Layer
(1 College of Civil Engineering and Architecture, Guangxi University, Nanning 530004; 2 Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu 610031; 3 Shenzhen Municipal Design & Research Institute Co. Ltd., Shenzhen 518029)
Abstract The construction of the Kunming Metro Line marks the first time China has built a tunnel in a soft layer containing peat soil using the shield method. Focusing on the engineering practices for this metro line, a corrected Peck formula is set up to calculate the ground surface settlement considering the influence of the construction of the first tunnel tube on the second tunnel tube in a soft layer containing peat soil. The law of ground settlement caused by shield construction is studied and compared to the empirical formula for ground settlement prediction. The results from this method and the numerical simulation agree very well with the measured data and can be used to analyze the shield-induced deformation law of soft ground containing peat soil. Compared to the change rate of ground surface settlement outside of the second tunnel tube, the change rate is larger for the first tunnel tube and its transverse settlement range is smaller, while the maximum settlement occurs between the center line of the two tunnel tube axes and first tunnel tube axis, and is caused by the construction of the first tunnel tube. Based on monitoring data from shield construction, the technical countermeasures against ground deformation caused by shield construc? tion in soft stratum containing peat soil are proposed.
Abstract：
The construction of the Kunming Metro Line marks the first time China has built a tunnel in a soft layer containing peat soil using the shield method. Focusing on the engineering practices for this metro line, a corrected Peck formula is set up to calculate the ground surface settlement considering the influence of the construction of the first tunnel tube on the second tunnel tube in a soft layer containing peat soil. The law of ground settlement caused by shield construction is studied and compared to the empirical formula for ground settlement prediction. The results from this method and the numerical simulation agree very well with the measured data and can be used to analyze the shield-induced deformation law of soft ground containing peat soil. Compared to the change rate of ground surface settlement outside of the second tunnel tube, the change rate is larger for the first tunnel tube and its transverse settlement range is smaller, while the maximum settlement occurs between the center line of the two tunnel tube axes and first tunnel tube axis, and is caused by the construction of the first tunnel tube. Based on monitoring data from shield construction, the technical countermeasures against ground deformation caused by shield construc? tion in soft stratum containing peat soil are proposed.
2017, Vol. 54 