新建工程基坑开挖及结构施工对既建下卧隧道的影响研究

随着城市建设的发展，地面工程和地下工程交叉建设的情况越来越多，新建工程对既有建筑产生影响的情况不可避免。因此，在保证既有工程结构安全的前提下建设新的工程已成为众多学者关注的重要问题之一。针对某已建隧道上方工程建设，分别采用Abaqus有限元数值模拟分析法和简化的规范角点法进行对比分析，评价隧道上方工程的基坑开挖及后续的结构施工对既建下卧公路隧道的影响。实施过程中的现场监测数据表明数值分析法和传统的土力学理论法在此类施工边界清晰、荷载施加明确的工程中的有效性并保障了工程的安全。研究还表明，二维分析模型不仅分析计算工作量相对较小，相较于考虑三维的实际工程安全性更有保障。本工程的成功经验可为类似工程的设计和施工提供有益的工程参考和借鉴。

Effect of foundation pit excavation and structural construction of new engineering on existing underlying tunnel

With the development of city construction, it is common to see more and more cross construction phenomena of the ground engineering and the underground engineering, which unavoidably contributes to the effect of the new construction on the existing construction. Therefore, on the premise of ensuring the safety of the existing construction, how to construct new projects has become one of the important issues for numerous scholars. In this paper, the finite element numerical simulation analysis method of ABAQUS and the simplified specification corner-points method are applied to analyze comparatively an engineering construction adjacent to the existing underlying tunnel. On this basis, the effects of the pit excavation and its subsequent construction on the underlying existing tunnel are evaluated. The field monitoring data demonstrate that the two methods, i.e. the numerical analysis method and the traditional theory of soil mechanics method, are coincidently available in such engineering construction which has clear boundary and explicit load and can secure engineering. The research also shows that the two-dimensional analysis model not only has the smaller calculation workload, but also has more security compared with a three-dimensional model considering practical engineering conditions.