装配式地铁车站拆撑工况下围护结构内力及变形分析

Analysis of internal force and deformation of prefabricated underground station under the working condition of removing support

以青岛市某装配式地铁车站为例,基于审查角度采用数值模拟方法研究设计方案在装配环拼装过程中因“换撑拆撑”工况引起的围护墙变形及内力变化趋势,得出以下结论:①拆撑工况下按平面验算钢支撑受力较笼统且不安全,设计时应考虑施工步序的空间影响范围;②采用支撑加密方案可降低钢支撑内力及围护墙变形,但加密3跨与加密1跨对结构变形和内力影响基本相同,对于地质条件好的地段可酌情采取不加密方案,提高施工效率;③装配环回筑过程中加强监测频率,尤其是拆撑后及时监测,监测点宜按第1道混凝土支撑位置及间距布设;④围护结构和主体结构间的肥槽宜按第1道混凝土支撑间距及时回填,可有效限制围护墙侧向位移发展。相关研究可为其他采用内支撑围护体系的装配式地铁车站设计审查提供参考和借鉴。

Taking a prefabricated underground station in Qingdao city as an example,a numerical simulation method is adopted to study the deformation and internal force variation trend of the envelope caused by the“replacing and removing support”condition in the assembly ring assembly process of the design scheme from the perspective of review,and the following conclusions are drawn:①The force calculation of the steel support according to the plane checking under the condition of removing the support is more general and insecure,and the design should consider the spatial influence range of the construction sequence;②The use of support intensify scheme can reduce the internal force of steel support as well as the enclosure wall deformation,but the intensify of 3 spans and the intensify of 1 span have basically the same impact on the deformation of the structure and the internal force.For the area with good geological conditions,the non-intensify scheme can be adopted as appropriate to improve the construction efficiency;③The monitoring frequency should be strengthened during the process of building back of the assembly ring,especially after the removal of the support in a timely manner,the monitoring point should be arranged according to the position and spacing of the first concrete support;④The fertilizer tank between the enclosure structure and the main structure should be backfilled in time according to the spacing of the first concrete support,which could effectively limit the development of lateral displacement of the enclosure wall.