桥梁桩基对既有地铁隧道的影响分析

Analysis on Impact of Bridge Pile Foundations on Existing Subway Tunnels

摘要:

为评估桥梁桩基施工时对既有地铁隧道的潜在影响，以坪山大道-东纵路路口跨河桥项目为例，利用Midas GTS NX建立了包含土层、地铁隧道及桥梁桩基的三维有限元模型，模拟了桩基施工全过程，并分析其对地铁结构位移的影响，结果表明：桥梁桩基施工引起的隧道结构最大水平位移为0.08 mm，最大竖向位移为1.08 mm，满足地铁安全运营要求；桥桩施工产生的土体卸荷耦合效应导致地铁结构上抬变形，为此提出在临地铁侧桩基中采用全套管跟进施工工艺，可有效降低桥梁桩基施工对地铁结构的影响；同时在施工期间需加强对地铁结构实时监测，以保证地铁安全运营。

Abstract:

To evaluate the potential impact of bridge pile foundation construction on existing subway, taking the cross-river bridge project at the intersection of Pingshan Avenue and Dongzong Road as an example, Midas GTS NX is used to establish a three-dimensional finite element model containing soil layers, subway tunnels and bridge pile foundations, which simulates the entire process of pile foundation construction and analyze its influence on subway structure displacement. The results show that the maximum horizontal displacement of tunnel structure caused by bridge pile foundation construction is 0.08 mm, and the maximum vertical displacement is 1.08 mm, which meets the requirements of safe operation of the subway. The coupling effect of soil unloading caused by bridge pile construction leads to the uplift deformation of subway structure. Therefore, it is proposed to adopt the full casing follow-up construction technology in the pile foundation near the subway, which can effectively reduce the influence of bridge pile foundation construction on subway structure. At the same time, it is necessary to strengthen the real-time monitoring of the subway structure during the construction period to ensure the safe operation of the subway.