Soil Stress of Shield Tunnel Face in Sands under High Hydraulic Pressure

Abstract:

Based on the under river tunneling project of Nanjing Metro Puzhulu-Binjianglu interval, a numerical model was built to simulate the process of losing stability, variation of soil stress and the soil arching effect caused by soil stress redistribution under high hydraulic pressure were studied. The results show that, compared to no hydraulic pressure, the limit supporting pressure is reached when smaller soil deformation has occurred and it is much greater under high hydraulic pressure. Along the depth from the bottom, soil vertical stress first decreases and then remains unchanged with increasing face displacement; Soil horizontal stress first decreases and then increases slightly. Soil lateral pressure coefficient first increases and then decreases along the depth from the bottom. Soil vertical and horizontal stress decrease in front of the tunnel face, where the failure region forms. Soil vertical stress decreases and horizontal stress increases above the failure region, where the vault region forms. Soil vertical stress increases and horizontal stress decreases around the failure region, where the skewback region forms. The results are conductive to better reveal the failure mechanism and determine the limit supporting pressure under high hydraulic pressure.

• Periodical: Advanced Materials Research (Volumes 588-589)
• Pages: 1983-1987
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.588-589.1983
• Online since: November 2012
• Authors: Meng Qiao Chen, Jian Kun Liu, Jun Hua Xiao
• Keywords: Face Stability, High Hydraulic Pressure, Shield Tunnel, Soil Arching Effect, Soil Stress

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