临近地铁隧道的深基坑开挖分析

随着城市发展和市区土地的紧缺，临近地铁隧道的城区将不可避免地受工程建设活动的影响。而基坑开挖将改变周围土体的应力状态，使临近隧道产生相应变形和内力，影响隧道的正常使用和地铁的安全。以上海某临近隧道的基坑工程为背景，采用Mohr-Coulomb弹塑性模型，运用有限元方法计算模拟了基坑开挖的不同阶段。分析结果与现场实测结果基本吻合，这表明有限元方法能很好地模拟此类问题并为工程的设计和施工提供理论和计算支持：同时也对不同的施工方案运用进行了数值模拟。模拟结果显示，此类工程施工时采用合理的开挖方式能显著地减少对地铁隧道的影响。

ANALYSIS OF DEEP PIT EXCAVATION ADJACENT TO TUNNEL

Engineering activities are inevitable in the urban region adjacent to the current metro tunnel with the continuous city development and increased needs for land of building. But the deep excavation of the foundation pit adjacent to the tunnel will change the stress state of the neighboring soil. And the deformation of tunnel will be induced which will cause impair to the daily operation and the safety of tunnel. According to the practice of deep excavation neighboring the tunnel in Shanghai, the application of elastoplastic finite element method with Mohr-Coulomb model to simulate different construction stage of deep pit excavation is presented. The results show good agreement with the field test data which show that the finite element method can provide good simulation for this kind of engineering activity and provide convincing computing results for the design and construction. Different construction method, furthermore, is simulated by the numerical method and the calculated results suggest that the rational excavation method will reduce the negative influence of the tunnel and ensure the success of the whole project.