黄土地区给排水工程深基坑施工对临近地铁隧道影响分析

Analysis of the Impact of Deep Excavation Construction of Water Supply and Drainage Engineering in Loess Plateau on Nearby Subway Tunnels

随着我国轨道交通事业的高速发展,深基坑工程紧邻地铁结构建设的案例逐渐增多,深基坑自身和既有地铁结构变形控制成为研究热点。本文以黄土地区某排水工程基坑临近已运营地铁隧道为工程实例,通过Midas GTS建立三维有限元模型,分析了分段基坑开挖及排水工程运营反复蓄水过程,周边地层、基坑支护结构和地铁隧道结构的变形特征。结合现场实测数据,明确了地层和隧道结构变形规律,验证了数值模拟的可靠性。研究表明:本基坑采取的支护体系并进行分布施工后,可有效控制地层、支护结构、地铁隧道变形。地层变形、基坑支护结构自身以及引起的隧道结构变形值均满足制定的变形标准及规范要求要求。泵站建成运营期间产生的附加荷载对地铁结构影响极小。监测数据和模拟结果吻合度极高,地层沉降和地铁隧道沉降误差仅为21%、28%。本研究成果可为类似工程提供参照。

With the rapid development of rail transit in China,there are more and more cases of deep foundation pit close to subway structure construction.In this paper,a 3D finite element model based on MIDAS GTS is established for a drainage project near an operating subway tunnel in loess area,deformation characteristics of surrounding stratum,foundation pit support structure and subway tunnel structure.Combined with the field measured data,the deformation law of stratum and tunnel structure is clarified,and the reliability of numerical simulation is verified.The research shows that the deformation of stratum,support structure and subway tunnel can be effectively controlled by the support system adopted in the foundation pit and distributed construction.The deformation of stratum,the supporting structure of foundation pit and the resulting deformation of tunnel meet the requirements of the deformation standards and codes.The additional load produced during the construction and operation of the pumping station has little influence on the subway structure.The monitoring data and simulation results are in good agreement with each other,and the error between ground settlement and subway tunnel settlement is only 21%and 28%.The results of this study can provide reference for similar projects.