地铁施工对管线的影响

隧道支护结构-土体三维有限元分析模型计算与施工监控量测相结合,分析北京地铁4号线黄庄站施工对地下管线的影响,并根据有关管线安全性的评价标准分析和预测地下管线的安全性。采用等效方法模拟钢架、锚杆;采用能承受轴弯性能的空间等参壳单元模拟初期支护及临时结构;采用遵循有限变形理想弹塑性本构关系和Drucker-Prager屈服准则的空间等参实体单元,模拟二次衬砌和围岩。数值模拟计算结果表明,开挖完成后的最大地表沉降预测值为121.63 mm,不超过127.27 mm的管线安全性要求,管节差异沉降亦不超过控制标准。但由于黄庄站地层存在着比较多的空洞,且地层富水和管线下漏水,因此为保证管线的正常使用,仍须采取措施控制地表沉降。

Influence of Metro Construction on Underground Pipeline

The influence of metro construction on the underground pipeline at Huangzhuang station of No.4 line in Beijing is analyzed with 3D finite element calculation of supporting construction of tunnel and soil and combining with the monitoring and measuration of construction.The safety of underground pipeline is analyzed and predicted according to related criterion for safety assessment of pipeline.The steel frame and bolt are simulated by equivalent method.The preliminary bracing and temporary construction are simulated with space iso-parametric shell element that can bear axle bending.The secondary lining and surrounding rock are simulated with space iso-parametric solid element that follows constitutive equations of finitude deformation ideal elastic-plasticity and yield criterion of Drucker-Prager.Calculation result shows that the maximum ground subsidence predicated is 121.63 mm after construction,which cannot overrun the safety request of pipeline,which is 127.27 mm.The differential subsidence is also not overrun the control criterion.Since there are many cavities in the stratum at Huangzhuang station,at the same time there is also much water in the stratum and leakage water of pipeline,we must take measures to control the ground subsidence so as to guarantee the normal use of pipeline.