大跨度地下无柱车站临时支撑卸载方案优化与现场监测  

Optimization for temporary support unloading scheme and on-site monitoring of large-span column-free underground station

作　　者：林泓志 侯文崎[2,3] 秦学锋 段罗 刘于晖 LIN Hongzhi;HOU Wenqi;QIN Xuefeng;DUAN Luo;LIU Yuhui(China Railway No.2 Engineering Group Co.,Ltd,Chengdu 610031,China;School of Civil Engineering,Central South University,Changsha 410075,China;Mechanical Teaching and Experimental Center,Central South University,Changsha 410075,China;China Railway No.2 Bureau Group Fifth Engineering Co.,Ltd,Chengdu 610031,China)

机构地区：[1]中铁二局集团有限公司,四川成都610031 [2]中南大学土木工程学院,湖南长沙410075 [3]中南大学力学教学实验中心,湖南长沙410075 [4]中铁二局集团第五工程有限公司,四川成都610031

出　　处：《建筑结构学报》2023年第3期294-302,共9页Journal of Building Structures

基　　金：湖南省自然科学基金面上项目(2019JJ40385);中铁二局科技计划(ZTEJ-GXB(2019)085号)。

摘　　要：新建岗厦北综合交通枢纽车站为地下3层结构,中庭52 m×48 m范围为无柱大跨度结构。该结构构件类型繁多,建造过程涉及多重体系转换。其中核心区临时支撑卸载时机、卸载过程对已建结构受力状态的影响,是结构建造安全的关键因素。为此,在原建造方案的基础上,提出了多种临时支撑卸载对比方案。采用有限元分析方法,对比不同卸载方案对结构受力状态的影响,确定地下1层钢梁架设完成后为临时支撑卸载合理时机。相比于原设计方案,该方案可有效降低地下1层混凝土板应力,降幅达14%。在此基础上,为使地下1层钢梁受力状态变化更为平缓,进一步提出了“卸载-回顶-二次卸载”的优化方案,并应用于实际工程。现场监测结果表明,覆土荷载对结构受力状态影响最大,其次是二次卸载;卸载过程中结构受力状态变化平稳,表明所提出的优化方案安全、有效。The newly-built Gangshabei comprehensive transportation hub station is an underground structure with three floors. The design of the 48 m×52 m atrium of the station is completed without interior column. With complex types of structural components, multiple system transformations are involved in construction process. The unloading time of the temporary support, and how the unloading process would affect the stress state of the built structure are critical to the construction safety. Based on the original scheme, various temporary support unloading schemes were proposed. The influence of different unloading schemes on the structural stress state was compared through finite element simulation analysis. Unloading the temporary support after the erection of the steel girders on the first basement level is determined to be reasonable, which reduces the tensile stress of the concrete slab on the first basement level reduced by up to 14% compared to original plan. On this basis, to make the stress state of the steel girders on the first basement level change more smoothly, the “unloading-uplifting-secondary unloading” scheme was further proposed and applied to the actual structure. Field monitoring results show that earth covering load has the greatest impact on the structural stress state, then the secondary unloading. During the entire unloading process, the structural stress state changes smoothly, the optimized scheme is proved to be safe and effective.

关 键 词：大跨度地下无柱车站 临时支撑 卸载 回顶 有限元分析 现场监测 

分 类 号：TU93[建筑科学—结构工程] TU317.2