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A platform for research: civil engineering, architecture and urbanism
［Objective］ Determine the limit support pressure required to maintain tunnel face stability during the construction of double-line small clearance shield tunnel. ［Method］ The excavation stability of double-line small clearance shield tunnel is studied by using a combination of numerical simulation, theoretical analysis and engineering verification. Numerical simulation is used to analyze the instability mode and limiting support pressure of double-line small clearance shield tunnel face. Based on the numerical simulation results, an analytical model for the instability of a double-line shield tunnel excavation face is proposed, and the limit support pressure required to maintain the tunnel face stability is derived by using the limit equilibrium theory. ［Result & Conclusion］ During the construction process of the small-clearance shield tunnel, a combined soil arch will be formed. Under the action of the combined soil arch, the limit support pressure required to maintain the stability of the double-line small-clearance tunnel excavation surface will increase significantly. Theoretical analysis shows that when the clearance is less than 0.5 D (D is the tunnel diameter), the limit support pressure increases with the increase of the clearance; when the clearance exceeds 0.5D, the limit support pressure decreases with the increase of the clearance; when the clearance exceeds 2.0D, the combined soil arch cannot be formed, and the failure mode in this case is the same as that of the single-hole tunnel, and the clearance no longer affects the limit support pressure.
［Objective］ Determine the limit support pressure required to maintain tunnel face stability during the construction of double-line small clearance shield tunnel. ［Method］ The excavation stability of double-line small clearance shield tunnel is studied by using a combination of numerical simulation, theoretical analysis and engineering verification. Numerical simulation is used to analyze the instability mode and limiting support pressure of double-line small clearance shield tunnel face. Based on the numerical simulation results, an analytical model for the instability of a double-line shield tunnel excavation face is proposed, and the limit support pressure required to maintain the tunnel face stability is derived by using the limit equilibrium theory. ［Result & Conclusion］ During the construction process of the small-clearance shield tunnel, a combined soil arch will be formed. Under the action of the combined soil arch, the limit support pressure required to maintain the stability of the double-line small-clearance tunnel excavation surface will increase significantly. Theoretical analysis shows that when the clearance is less than 0.5 D (D is the tunnel diameter), the limit support pressure increases with the increase of the clearance; when the clearance exceeds 0.5D, the limit support pressure decreases with the increase of the clearance; when the clearance exceeds 2.0D, the combined soil arch cannot be formed, and the failure mode in this case is the same as that of the single-hole tunnel, and the clearance no longer affects the limit support pressure.
Study on Stability of Small Clearance Shield Tunnel Excavation Face
GAO Qi (author)
2025
Article (Journal)
Electronic Resource
Unknown
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