The numerical analysis method is adopted to study the vertical deformation mechanism of the retaining wall caused by unloading. A hypothetical model which considers the interaction between wall and soil, is established in the finite difference software. The ideal elastoplastic model is adopted to simulation the characteristics of contact property between soil and diaphragm wall. The vertical displacement of soil, the relative displacement of soil and wall and the distribution of friction under the 3 kinds of soil parameters are compared and analyzed. The results show that the vertical displacement of the wall can be divided into two parts the soil rebounded one and relatively sliding between subsoil and wall tips. The displacement of soil is mainly affected by unloading effect which is determined by soil parameter. The settlement of the wall decreases with the increase of soil cohesion. The uplift of the wall increases with the increase of friction angle. The relative sliding of wall tips and soil is governed by the frictional forces on two sides of the wall. With the increase of contact property, the frictional force increases and will lead to larger vertical displacements.
XIAO Xiao，LI Mingguang，CHEN Jinjian，XIA Xiaohe
. Vertical Deformation Mechanism of
Diaphragm Wall Due to Unloading in Deep Excavation[J]. Journal of Shanghai Jiaotong University, 2018
, 52(12)
: 1552
-1558
.
DOI: 10.16183/j.cnki.jsjtu.2018.12.002
［1］WANG J H, XU Z H, WANG W D. Wall and ground movements due to deep excavations in shanghai soft soils［J］. Journal of Geotechnical & Geoenvironmental Engineering, 2010, 136(7): 985-994.
［2］CHEN J J, ZHU Y F, LI M G, et al. Novel excavation and construction method of an underground highway tunnel above operating metro tunnels［J］. Journal of Aerospace Engineering, 2015, 28(6): A4014003.
［3］贾坚, 谢小林. 上海软土地区深大基坑卸荷变形机理［J］. 上海交通大学学报, 2009, 43(6): 1005-1010.
JIA Jian, XIE Xiaolin. Unloading deformation mechanism of deep-large excavat ion in Shanghai clay area ［J］. Journal of Shanghai Jiao Tong University, 2009, 43(6): 1005-1010.
［4］LI M G, CHEN J J, XU A J, et al. Case study of innovative top-down construction method with channel-type excavation［J］. Journal of Construction Engineering & Management, 2014, 140(5): 05014003.
［5］FINNO R J, ATMATZIDIS D K, PERKINS S B. Observed performance of a deep excavation in clay［J］. Journal of Geotechnical Engineering, 1989, 115(8): 1045-1064.
［6］范巍, 王建华, 陈锦剑. 连续墙与土体接触特性对深基坑变形分析的影响［J］. 上海交通大学学报, 2006, 40(12): 2118-2121.
FAN Wei, WANG Jianhua, CHEN Jinjian. The evaluation of deformation lnduced excavation considering the properties of diaphragm soil interface［J］. Journal of Shanghai Jiao Tong University, 2006, 40(12): 2118-2121.
［7］SHI J W, LIU G B, HUANG P, et al. Interaction between a large-scale triangular excavation and adjacent structures in Shanghai soft clay［J］. Tunnelling and Underground Space Technology, 2015, 50: 282-295.
［8］LIU G B, HUANG P, SHI J W, et al. Performance of a deep excavation and its effect on adjacent tunnels in Shanghai soft clay［J］. Journal of Performance of Constructed Facilities, 2016, 30(6): 04016041.
［9］XIAO X, ZHANG Y Q, LI M G, et al. Responses of the strata and supporting system to dewatering in deep excavations［J］. Journal of Shanghai Jiao Tong University (Science), 2017, 22(6): 705-711.
［10］TAN Y, LI M W. Measured performance of a 26 m deep top-down excavation in downtown Shanghai［J］. Revue Canadienne De Géotechnique, 2011, 48: 704-719.
［11］TAN Y, LI X, KANG Z J, et al. Zoned excavation of an oversized pit close to an existing metro line in stiff clay: Case study［J］. Journal of Performance of Constructed Facilities, 2015, 29(6): 04014158.
［12］TAN Y, HUANG R, KANG Z J, et al. Covered semi-top-down excavation of subway station surrounded by closely spaced buildings in downtown Shanghai: Building response［J］. Journal of Performance of Constructed Facilities, 2016, 30(6): 04016040.
［13］BURD H, DONG Y P, HOULSBY G T. Finite-element analysis of a deep excavation case history［J］. Géotechnique, 2016, 66(1): 1-15.
［14］Itasca Consulting Group Inc. Fast Lagrangian analysis of continua in 3 dimensions［M］. Minnesota: Itasca, 2016.
