盾构施工下穿城市匝道桥影响分析

Analysis on the Influence of Shield Construction Underneath Urban Ramp Bridges

为准确分析盾构隧道施工下穿桥梁对桩基的影响,以实例工程为背景,基于沉降理论估算双线隧道施工引起的地表沉降量,建立了双线盾构施工穿越桥梁桩基模型。运用数值模拟和现场施工监测相结合的研究方法,重点分析了盾构施工引起的地表沉降以及对桥梁产生的竖向沉降和水平位移情况。结果表明:采用注浆加固可有效降低盾构施工对地表沉降的影响;在未加固的情况下,产生的竖向沉降满足控制标准值8 mm要求,水平位移不完全满足控制标准值2.4 mm要求;采用注浆加固后,桩基发生的竖向沉降和水平位移都有显著降低,且均满足控制标准值要求。结合现场施工监测结果进行分析,验证了数值模拟结果的准确性,并对今后类似工程施工具有一定的参考价值。

In order to analyze the influence of shield tunnel construction on pile foundation,based on the settlement theory,the ground settlement caused by double-line tunnel construction is estimated,and the pile foundation model of double-line shield construction across bridge is established.The surface settlement caused by shield construction and the vertical settlement and horizontal displacement of the bridge are analyzed with the method of numerical simulation and field construction monitoring.The results show that the use of grouting reinforcement can effectively reduce the impact of shield construction on surface settlement.Without reinforcement,the resulting vertical settlement meets the requirement of control standard value 8mm,and the horizontal displacement does not fully meet the requirement of control standard value 2.4mm.After using grouting reinforcement,the vertical settlement and horizontal displacement of the pile foundation are significantly reduced,and they both meet the control standard value.Combined with the monitoring results of field construction,the accuracy of the numerical simulation results is verified,and has a certain reference value for the construction of similar projects in the future.