隧道下穿引起地下管线下沉的主控因素分析

城市地铁建设中,隧道开挖可能损坏上部土体中埋设的既有管线。如何控制管线沉降,从而保证其安全是地铁施工中必须考虑的问题。利用ANSYS有限元分析软件,模拟隧道开挖对刚性接口地下管线的影响,充分考虑了土质、管线参数及盾构施工参数等因素,分析了地下管线在不同因素影响下的沉降变化规律。计算结果表明,管线本身参数(除管材、直径外)对其沉降的影响相对较小,而土质及盾构施工参数对管线沉降的影响较为显著,应当予以重视。通过对北京某地铁区间隧道正交下穿钢筋混凝土雨水管的沉降实测资料与3种假设工况沉降计算值的对比分析,验证了前述结论的正确性。

Analysis on main controlling factors of settlement induced by tunnel beneath through underground pipeline

In the process of subway construction,tunnel excavation may damage existing pipelines buried in the upper soil. How to control the pipeline settlement,so as to ensure the safety must be considered in subway construction. Utilizing ANSYS software,the fine models were established to study the effects of tunnel excavation on pipelines with rigid interface. In the simulation,soil properties,pipeline details and shield construction parameters were considered. The results showed that pipeline details（ in addition to material and diameter） have smaller influence on pipeline settlement,while soil properties and shield construction parameters have great influences on pipeline settlement,and should be attracted particular attention. The correctness of foregoing conclusions were evaluated by the comparative analysis between the monitoring data from Beijing subway tunnel beneath through rainwater pipeline and the calculated data from three hypothetical project cases.