天津某半逆作法基坑结构柱隆起变形实测分析

(1.中铁隧道局集团路桥工程有限公司,天津 300308; 2.天津大学 建筑工程学院,天津 300350; 3.天津城建大学 建筑设计研究院有限公司,天津 300192)

基坑; 半逆作法; 结构柱; 隆起变形; 监测

Analysis on heave deformation of columns for excavation with semi top-down method in Tianjin
XIA Zengyin1, ZHENG Gang2, DENG Xu3, JI Yetao1, CHENG Xuesong2, MENG Lingbo1

(1.China Railway Tunnel Group Road & Bridge Engineering Co., Ltd., Tianjin 300308, China; 2.School of Civil Engineering, Tianjin University, Tianjin 300350, China; 3.Tianjin Chengjian University Institute of Architectural Design Co,. Ltd, Tianjin, 300192)

excavation; semi top-down method; columns; heave; monitoring data

DOI: 10.15986/j.1006-7930.2022.05.003

备注

半逆作法基坑施工可以综合明挖顺作法与盖挖逆作法的各自优势,节约造价且便于施工.天津某交通枢纽广场基坑采用环形盖挖逆作、中心明挖顺作的半逆作法施工,通过对结构柱隆沉变化实测数据进行分析研究表明,结构柱的竖向变形基本表现为开挖阶段隆起现象显著,层板施工阶段隆起稳定甚至发生轻微沉降.当基坑开挖深度较浅时,结构柱的隆起变形量相对较小,随着开挖深度增加隆起量急剧增大.半逆作法基坑的结构柱的最终隆起量为(0.19%~0.35%)D(D为基坑开挖深度),数值更接近于顺作法基坑,明显大于盖挖逆作法施工的基坑,这对地下结构安全性的影响也更加严重.在此基础上提出设计施工中的一些注意事项,为今后类似工程的建设提供参考.
The construction of excavation with semi top-down method can integrate the respective advantages of bottom-up method and top-down method, save the cost and facilitate the construction. The excavation of one transport hub square in Tianjin is constructed by the semi top-down method with the top-down method in the periphery and the bottom-up method in the central part. Through the analysis of the monitoring data of columns heave and settlement, the vertical deformation of columns shows that the heave phenomenon is significant in the excavation stage, and stable or even slight settlement in the laminate construction stage. When the depth of the excavation is shallow, the heave of the column is relatively small, and the heave increases sharply with the increase of the excavation depth. The final heave of the columns of the excavation with the semi top-down method is(.19%~0.35%)D(D is the depth of excavation), which is closer to the bottom-up method excavation and significantly greater than the top-down method excavation. And the heave of the columns has a more serious impact on the safety of the underground structure. On this basis, some precautions in design and construction are put forward, which can provide reference for the construction of similar projects in the future.