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| DEM simulation of vertical earth pressure on deep tunnel in sand |
| LIU Hongda1,2, YANG Tianliang3, ZHANG Dongmei1,2*
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1. Key Laboratory of Geotechnical and Underground Engineering of Minister of Education, Shanghai 200092, China;
2. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
3. Key Laboratory of Land Subsidence Monitoring and Prevention, Ministry of Natural Resources, Shanghai Institute of Geological Survey, Shanghai 200072, China |
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Abstract With the development and utilization of urban underground space, deep buried shield tunnels get more and more popular. How to determine the vertical earth pressure above deep buried shield tunnel is the key issue for reasonable segment design. With the increase of tunnel depth, the soil arch effect is increased and the disturbed zone will be formed above the tunnel. Numerical investigation of the excavation of deep buried tunnel in sand was carried out using PFC2D to observe the shape of the disturbed zone above the tunnel. Based on it, a modified failure mechanism of TERZAGHI was improved and a new computing method of vertical earth pressure above deep buried tunnel in sand was proposed. The results showed that the disturbed zone was triangular, the sliding surface was not vertical which was assumed by TERZAGHI. The lateral pressure coefficient of the sliding surface was larger than the suggested value of TERZAGHI. Finally, the results of the proposed method was verified using the field observed data. The proposed method can be used to analyze the vertical earth pressure above deep buried tunnel.
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Published: 04 November 2020
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