刘佩冬

摘要：研究深基坑开挖变形模式和破坏机理对城市地铁隧道的影响。基于土体的莫尔库仑剪切第3主应力破坏条件，通过MIDAS/GTS建立基坑开挖对临近地铁隧道的数值模型，控制基坑和地铁隧道的位置关系，观察预设观测点的位移变化，得到基坑开挖对临近地铁隧道的影响。结果表明：基坑开挖打破了原状土层应力状态是影响地铁隧道的主要因素，即第3主应力的释放;通过控制变量法控制基坑和隧道的位置关系L和L来观测隧道断面位移变化可为实际工程提供指导意义;随着基坑与地铁隧道间距的变化靠近基坑的观测点B偏移量较大，并通过观测发现加固基坑底部对控制临近土体的偏移具有很大帮助;改变基坑和地铁隧道竖向位移关系时，观测点的竖向偏移较大而水平偏移较小，主要是由于基坑底部的卸荷引起的土层偏移。

关键词：信息反馈;变形模式;地铁隧道;数值模拟

中图分类号：U417

文献标识码：A文章编号：1001-5922（2022）06-0133-05

Study on the influence of excavation of urban road foundation pit on adjacent metro tunnel

LIU Peidong

（Zhengzhou Road and Bridge Construction Investment Group Co.， Ltd.， Zhengzhou 450000， China

）

Abstract：In order to analyze deep foundation pit excavation deformation mode and failure mechanism and the influence on urban subway tunnel， this paper is based on the Mohr Coulomb soil shear the third principal stress damage conditions， through the MIDAS/GTS excavation of adjacent metro tunnel numerical model is set up， control of foundation pit and the location of the metro tunnel relation， to observe the displacement of the preset observation point of change， figure out the influence of foundation pit excavation on adjacent subway tunnel is obtained. The results show that the stress state of the undisturbed soil layer is the main factor affecting the subway tunnel， that is， the release of the third principal stress. By controlling the position relationship L and L between the foundation pit and the tunnel with the control variable method， the displacement of tunnel section can be observed， which can provide guidance for practical engineering. With the change of the distance between the foundation pit and the subway tunnel， the offset of the observation point B near the foundation pit is larger， and it is found through observation that strengthening the bottom of the foundation pit is of great help to control the migration of the adjacent soil. When the relationship between the vertical displacement of the foundation pit and the subway tunnel is changed， the vertical displacement of the observation point is larger and the horizontal displacement is smaller， which is mainly due to the soil layer migration caused by the unloading at the bottom of the foundation pit.

Key words：information feedback; deformation mode; subway tunnel; numerical simulation

隨着我国城市的不断发展，城市地下空间开发和利用日新月异[1]，随着基坑开挖深度的加深基坑周边土体的破坏机理和变形模式越复杂，并对地铁隧道等其他结构物造成很大的影响[2]。如何减小深基坑的开挖对地铁隧道等其他结构物的影响是保证其安全运营的基础。关于深基坑开挖对周边环境的影响有学者研究分析了：注浆加固对深基坑与邻近隧道作用的影响，并提出注浆加固联合多桩分阶支……