改建工程深基坑对地铁车站及区间隧道的影响分析

Effect of Filling and Grouting Reinforcement on Deep Foundation Pit Support Structure and Adjacent Tunnels

摘要: 本文以邻近运营轨道线路的深基坑改建工程为例，详细介绍了肋柱、支护桩与短锚杆、长锚索相结合的基坑支挡方案。原有基坑边坡高度由23.4 m加深至40 m，随着基坑的开挖，土压力不断增大，隧道原有的应力平衡状态被改变，偏压的受力模式更加明显，通过数值分析的手段模拟了从基坑改建到塔楼新建的全过程，得出各施工工况下隧道的变形值和应力值，相比于新建项目，增加了原有地下结构拆除的施工工况分析。另外超高层塔楼的风荷载和地震荷载数值较大，也单独作为一种工况进行了分析计算。数值分析的结果有利于指导基坑设计和施工，对影响隧道结构安全的风险源及发生时间进行预判。

Abstract: This paper takes the deep foundation pit reconstruction project adjacent to the operating track line as an example, and introduces the foundation pit supporting scheme combining the rib column, the supporting pile and the short anchor rod and the long anchor cable. The height of the original foundation pit slope is deepened from 23.4 m to 40 m. With the excavation of the foundation pit, soil pressure is continuously increased, the original stress balance state of the tunnel is changed, and the stress mode of the bias is more obvious. Through the method of numerical analysis, the whole process from the reconstruction of the foundation pit to the new construction of the tower was simulated, and the deformation value and stress value of the tunnel under various construction conditions were obtained. Compared with the new construction project, the analysis of the construction conditions of the original underground structure demolition is added. In addition, the wind load and seismic load of the super high-rise tower are large, and they are also analyzed and calculated separately as a working condition. The results of numerical analysis are helpful to guide the design and construction of foundation pits, and predict the risk sources and time of occurrence of tunnel structure safety.