隧道开挖对既有管线沉降的影响

隧道施工使周边管线的附加应力及变形加大,严重影响管线安全,而管线监测通常落后于施工,只有正确地预估管线沉降和沉降规律才能保证施工安全。针对这一问题,采用ANSYS分析软件,考虑管土之间的相互作用,模拟隧道台阶法施工的实际过程,探讨隧道浅埋暗挖施工对管线的影响,分析其沉降规律,并与实测值对比,研究管线直径、埋深、材质、埋置年代等对其沉降的影响规律。研究结果表明:模拟值略小于实测值,但沉降规律一致,地下水的损失以及地面荷载都将加大管线沉降;管线的最大沉降与管线直径大致成正比关系;埋深对管线变形的影响较大,近地面处随埋深的加大管线沉降加大,靠近管线处随埋深的加大沉降减小;不同材质管线的沉降从大到小依次是PVC管、混凝土管、铸铁管、钢管;壁厚对管线的影响不大。

3D finite element analysis of effect on pipeline settlement in tunnel excavation

The additional stress and deformation of pipeline will increase due to the construction of the tunnel, which affects the pipeline safety. However, pipeline monitoring generally lags behind the construction, only if correctly estimating pipeline settlement and its rules will enable the construction safety. To solve this problem, by considering the interaction between the pipeline and soil, the pipeline diameter and material and buried depth effects on settlement are studied. The results show that groundwater losses and ground load are increasing the pipeline settlement; the maximum settlement of pipeline and its diameter are almost direct proportion; depth has a great influence on the pipeline deformation, closing to the ground along with the increase of buried depth pipeline settlement, but the depth decrease near the pipeline; the settlement of different material pipeline from big to small in turn is PVC pipe, concrete pipes, cast iron pipe, steel pipe; the influence of wall thickness of pipeline is small.