Please wait a minute...
JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE)  2019, Vol. 53 Issue (1): 51-60    DOI: 10.3785/j.issn.1008-973X.2019.01.006
Civil Engineering     
Case study on braced excavation with P-CFST for top internal support
GUO Xue-yuan1,3, ZHANG Ming-ju1, MA Dong2, HUANG Li-xin2, WANG Wu-xian2, WANG Chun-sheng2, YANG Shi-peng2, QIAO Jing-sheng3
1. Beijing Collaborative Innovation Center for Metropolitan Transportation, Beijing University of Technology, Beijing 100124, China;
2. China Railway 16th Bureau Group Co., LTD., Beijing 100018, China;
3. Tangshan Basic Innovation Team for Applied Research of Steel-Slag Mixture, Tangshan College, Tangshan 063000, China
Download:   PDF(1653KB) HTML
Export: BibTeX | EndNote (RIS)      

Abstract  

A prefabricated concrete-filled steel tube (P-CFST) bracing was applied for the top internal support of supporting structure aiming at the difficulties of deep excavated depth and narrow working space in the excavation engineering of a shield shaft for Line 17 of Beijing Subway. The interval among bracings were enlarged by using P-CFST bracing resulting in being convenient for excavation and bracing erection. The whole process of excavation and support was simulated with a three-dimensional finite element model by ABAQUS. Systematic monitoring for axial force of bracing, deformation of fender piles, displacement of pile top and ground settlement were accomplished in implementary process of excavation. The security of excavation in combined support of P-CFST bracing and steel bracing was ensured. The spatial effect on deformation of supporting structure, surface of ground settlement and axial force of different bracing was analyzed. The simulation and monitoring results indicated that the deformation in same deep of supporting structure manifested shape of parabola or basin, and scope of spatial effect on deformation of supporting structure was less than 8 m. Contour line of ground settlement near foundation pit changed from arc to trapezoid. The location of biggest settlement first moved further and then moved back. Axial force of P-CFST bracing was more sensitive than steel bracing under influence of excavation and bracing erection. Design interval among bracings can be enlarged by applying high-powered P-CFST bracing in first internal support, and deformation of supporting structure and stratum may be effectively controlled.



Received: 03 January 2018      Published: 07 January 2019
CLC:  TU942  
Cite this article:

GUO Xue-yuan, ZHANG Ming-ju, MA Dong, HUANG Li-xin, WANG Wu-xian, WANG Chun-sheng, YANG Shi-peng, QIAO Jing-sheng. Case study on braced excavation with P-CFST for top internal support. JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE), 2019, 53(1): 51-60.

URL:

http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2019.01.006     OR     http://www.zjujournals.com/eng/Y2019/V53/I1/51


基坑工程首道内支撑采用P-CFST的工程实例研究

针对北京地铁17号线某盾构竖井基坑工程开挖深度大、作业空间小的难点,围护结构首道支撑位置采用新型装配式钢管混凝土(简称P-CFST)支撑结构,扩大了支撑间距,便于基坑开挖、出土和支撑架设作业. 利用ABAQUS软件建立三维有限元模型,开展基坑开挖全过程数值模拟. 在工程实施过程中,对支撑轴力、围护桩水平位移、桩顶水平位移和地表沉降进行系统监测,保证了P-CFST支撑和钢支撑组合支护下的基坑施工安全,研究盾构竖井围护结构变形的空间效应、地表沉降曲面形态、不同位置处的支撑轴力关系等. 由模拟和监测结果的分析表明:围护桩同一深度上变形呈现抛物线形状或“盆形”,空间效应对盾构井围护结构变形的影响主要发生在距离基坑阴角小于8 m的范围内;基坑附近地表沉降等值线形状经过“圆弧形”-“陀螺形”-“梯形”变化,最大地表沉降位置经历由近及远、再向基坑靠近的移动过程;首道P-CFST支撑轴力对地层开挖、支撑架设等工况的影响更加敏感,大于架设深度更大的2、4道钢支撑轴力. 盾构竖井基坑工程内撑式围护结构首道支撑选用高刚度、高承载力的P-CFST内支撑,扩大了设计间距,围护结构和周围地层变形得到了有效控制.

[1] WHITTLE A J, CORRAL G, JEN L C, et al. Prediction and performance of deep excavations for courthouse station, Boston[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 141(4):04014123.
[2] TAN Y, WEI B, ZHOU X, et al. Lessons learned from construction of Shanghai metro stations:importance of quick excavation, prompt propping, timely casting, and segmented construction[J]. Journal of Performance of Constructed Facilities, 2014, 29(4):04014096.
[3] 谭勇, 康志军, 卫彬, 等. 上海软土地区某地铁风井深基坑案例分析[J]. 浙江大学学报:工学版, 2016, 50(06):1048-1055 TAN Yong, KANG Zhi-jun, WEI Bin, et al. Case study on deep excavation for metro ventilation shaft in Shanghai soft clay[J]. Journal of Zhejiang University:Engineering Science, 2016, 50(06):1048-1055
[4] WANG W D, WANG J H, LI Q, et al. Design and performance of large excavations for Shanghai Hongqiao International Airport Transport Hub using combined retaining structures[J]. Journal of Aerospace Engineering, 2014, 28(6):A4014002.
[5] XU C, CHEN Q, WANG Y, et al. Dynamic deformation control of retaining structures of a deep excavation[J]. Journal of Performance of Constructed Facilities, 2015, 30(4):04015071.
[6] PARK J S, JOO Y S, KIM N K. New earth retention system with prestressed wales in an urban excavation[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135(11):1596-1604.
[7] 刘发前. 装配式型钢内支撑稳定性设计[J]. 城市道桥与防洪, 2016(05):81-83 LIU Fa-qian. Stability design of prefabricated steel bracing[J]. Urban Roads Bridges and Flood Control, 2016(05):81-83
[8] 张明聚, 杜永骁. 一种基坑支护用的方钢管混凝土内支撑结构:CN102635118A[P]. 2012-08-15.
[9] 王祺国. 一种拆除简便的深基坑支撑施工技术[J]. 建筑施工, 2013, 35(10):886-888 WANG Qi-guo. A kind of convenient construction technology for inner-bracing demolition of deep excavation[J]. Building Construction, 2013, 35(10):886-888
[10] 张明聚, 郭雪源, 马栋, 等. 基坑工程装配式钢管混凝土内支撑体系设计方法[J]. 北京工业大学学报, 2016, 42(12):88-96 ZHANG Ming-ju, GUO Xue-yuan, MA Dong, et al. The design methods of the concrete-filled steel tube inner-bracing system for deep excavation[J]. Journal of Beijing University of Technology, 2016, 42(12):88-96
[11] 林卫东. 西安地铁凤栖原车站深基坑施工降水技术研究[J]. 铁道工程学报, 2013, 30(01):100-104 LIN Wei-dong. Research on water reduction technology for deep foundation pit construction of Fengqiyuan station of Xi'an metro[J]. Journal of Railway Engineering Society, 2013, 30(01):100-104
[12] 张明聚, 郭雪源, 李战国, 等. 高性能填充轻集料混凝土试验研究[J]. 北京工业大学学报, 2017, 43(06):919-928 ZHANG Ming-ju, GUO Xue-yuan, LI Zhan-guo, et al. Experimental study on high performance filling lightweight aggregate concrete[J]. Journal of Beijing University of Technology, 2017, 43(06):919-928
[13] 北京市住房和城乡建设委员会. 基坑工程内支撑技术规程:DB11/940-2012[S]. 北京:中国建筑标准设计研究院, 2012.
[14] RANDOLPH M F, WROTH C P. Application of the failure state in undrained simple shear to the shaft capacity of driven piles[J]. Geotechnique, 1981, 31(1):143-157.
[15] 徐江, 龚维明, 穆保岗, 等. 软土区某地铁深基坑施工过程数值模拟及现场监测[J]. 东南大学学报:自然科学版, 2017, 47(03):590-598 XU Jiang, GONG Wei-ming, MU Bao-gang, et al. Numerical simulation and monitoring on construction process of deep pit of subway station in soft clay[J]. Journal of Southeast University:Natural Science Edition, 2017, 47(03):590-598
[16] 陈树林, 张峰, 代楠. 紧邻既有结构的深基坑受力变形特性分析[J]. 上海交通大学学报, 2016, 50(10):1658-1664 CHEN Shu-lin, ZHANG Feng, DAI Nan. Studies on stress and deformation behaviors of deep excavations adjacent to substructures[J]. Journal of Shanghai Jiaotong University, 2016, 50(10):1658-1664
[17] 宋广, 宋二祥. 基坑开挖数值模拟中土体本构模型的选取[J]. 工程力学, 2014, 31(05):86-94 SONG Gang, SONG Er-xiang. Selection of soil constructive models for numerical simulation of foundation pit excavation[J]. Engineering Mechanics, 2014, 31(05):86-94
[18] 贾堤, 石峰, 郑刚, 等. 深基坑工程数值模拟土体弹性模量取值的探讨[J]. 岩土工程学报, 2008, 30(增1):155-158 JIA Di, SHI Feng, ZHENG Gang, et al. Elastic modulus of soil used in numerical simulation of deep foundation pits[J]. Chinese Journal of Geotechnical Engineering, 2008, 30(Suppl.1):155-158
[19] 丁勇春, 程泽坤, 王建华, 等. 临江基坑变形及受力性状三维数值分析[J]. 岩土工程学报, 2012, 34(增1):243-247 DING Yong-chun, CHENG Ze-kun, WANG Jian-hua, et al. Three-dimensional numerical analysis of deformation and mechanical behavior of deep excavations adjacent to river[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(Suppl.1):243-247
[20] 李磊, 段宝福. 地铁车站深基坑工程的监控量测与数值模拟[J]. 岩石力学与工程学报, 2013, 32(增1):2684-2691 LI Lei, DUAN Bao-fu. Monitoring measurement and numerical simulation for deep foundation pit of subway station[J]. Chinese Journal of Rock Mechanics and Engineering, 2013, 32(Suppl.1):2684-2691

No related articles found!