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考虑盾构隧道施工中产生的地应力释放,采用有限元法模拟了不同地质条件下的盾构隧道管片的内力分布。将有限元模拟的盾构隧道施工引起的地表沉降值与现场观测值的对比,确定了某地铁隧道施工引起的地应力释放率。有限元模拟分析结果表明,地表的最大沉降近似与地应力释放率成正比,并建立了两者之间的映射关系。研究表明,与不考虑地应力释放率相对比,实际的管片最大弯矩、最大轴力和最大剪力分别下降了48%,62%和49%。考虑盾构施工引起地应力释放所得到的管片内力会更加接近实际的情况。
Considering the release of geostress in the construction of shield tunnel, the internal force distribution of shield tunnel segments under different geological conditions is simulated by finite element method. The comparison of the ground settlement value caused by the shield tunneling with the finite element simulation and the observed values in the field shows that the release rate of the earth stress caused by the subway tunnel construction is determined. Finite element simulation results show that the maximum settlement of the earth’s surface is proportional to the rate of release of the earth stress, and the mapping relationship between the two is established. The results show that the actual maximum bending moment, the maximum axial force and the maximum shear force decrease by 48%, 62% and 49% respectively compared with those without considering the stress release rate. Considering the stress caused by the shield construction, the internal force of the pipe will be closer to the actual situation.