Hoop stiffness and its reduction factor of diaphragm wall panels for circular excavation
CUI Jian-feng1, HU Jian-hua1, 3, HE Wei2, HE Yao-bei3
1. College of Civil Engineering, Hunan University, Changsha 410082, China; 2. School of Civil Engineering and Architecture, Changsha University of Science & Technology, Changsha 410114, China;; 3. Hunan Provincial Communication Planning, Survey and Design Institute, Changsha 410008, China
Abstract：Since the joints between diaphragm wall panels lead to reduction of hoop stiffness in circular excavation, it is necessary to propose a method to quantitatively evaluate the hoop stiffness correction coefficient α. The stress-strain curves of joints are first measured through the mechanical experiments on specimens containing joints and then compared to those of intact concrete cubes, separately considering the two typical locations for diaphragm wall panels with milling joint, in panels and between panels. For reliability purpose, the intact concrete cubes and specimens containing joints are both produced with concrete and slurry applied from a construction site. Then, the trilinear function is introduced to best fit the measured stress-strain curves, thus the formula for the stiffness correction coefficient α is proposed and subsequently applied to a real case analysis. The results show that the value of the stiffness correction coefficient α mainly depends on the average length of panel, the width of joints as well as the stiffness of joints and concrete. The value of α ranges between 0.485~0.514 in case of low hoop stress, and turns into a rise when the hoop stress exceeds 7.37 MPa, and reaches 0.545~0.581 when it rises up to 11 MPa. Further, the calculated results based on α obtained in the site tests indicate that it is efficient when considering the effect of joints by just taking α into account when the hoop stress stays at a low level, but the nonlinear stiffness of joints should be considered when the stress is high. In conclusion, an approach for quantitatively evaluating the hoop stiffness correction coefficient α is proposed and can be further applied for engineering application purpose.
崔剑峰,胡建华,贺炜,贺耀北. 圆形地下连续墙的环向刚度折减效应及修正方法研究[J]. 岩土工程学报, 2017, 39(11): 2132-2138.
CUI Jian-feng, HU Jian-hua, HE Wei, HE Yao-bei. Hoop stiffness and its reduction factor of diaphragm wall panels for circular excavation. Chinese J. Geot. Eng., 2017, 39(11): 2132-2138.
 SCHWAMB T, SOGA K. Numerical modelling of a deep circular excavation at Abbey Mills in London[J]. Géotechnique, 2015, 65(7): 604-619.  罗耀武, 凌道盛, 陈云敏, 等. 环形超深基坑围护结构受力变形特性分析[J]. 岩土力学, 2011, 32(2): 617-622. (LUO Yao-wu, LING Dao-sheng, CHEN Yun-min, et al. Mechanical and deformation characteristics of enclosure structure for annular extra-deep excavation[J]. Rock and Soil Mechanics, 2011, 32(2): 617-622. (in Chinese))  陈占力. 圆形地下连续墙截面设计[J]. 基础与结构工程, 2008, 31(2): 115-117. (CHEN Zhan-li. Cross section design of circular underground continuous wall[J]. Foundation & Structure Engineering, 2008, 31(2): 115-117. (in Chinese))  徐国平, 李建清. 圆形地下连续墙在悬索桥锚碇基础中的应用[J]. 公路, 2004(11): 47-51. (XU Guo-ping, LI Jian-qing. Circular underground continuous wall used in the suspension bridge anchorage foundation[J]. Highway, 2004(11): 47-51. (in Chinese))  林 鸣, 张 鸿, 吴 浩, 等. 润扬长江公路大桥北锚碇特深基础工程施工[J]. 建筑施工, 2002(4): 255-257. (LIN Ming, ZHANG Hong, WU Hao, et al. Construction of Runyang Yangtze River Highway Bridge’s northern anchorage foundation[J]. Buiding Information, 2002(4): 255-257. (in Chinese))  CABARKAPA Z, MURPHY J, POTTS D M. Design and performance of a large diameter shaft in Dublin boulder clay[C]// Foundations: Innovations, Observations, Design and Practice, 2003.  TAN Y, WANG D. Structural behaviors of large underground earth-retaining systems in shanghai i: unpropped circular diaphragm wall[J]. Journal of Performance of Constructed Facilities, 2015, 29(2): 04014058.  JTJ 303—2003 港口工程地下连续墙结构设计与施工规程[S]. 2003. (JTJ 303—2003 Design and construction technical code for diaphragm wall structure of port engineering[S]. 2003. (in Chinese))  JTG D63—2007 公路桥涵地基与基础设计规范[S]. 2007. (JTG D63—2007 Code for design of ground base and foundation of highway bridge and culverts[S]. 2007. (in Chinese))  陈富强, 杨光华, 张玉成, 等. 圆形地下连续墙结构设计中 α 系数取值探讨[J]. 岩土工程学报, 2012, 34(增刊): 203-206. (CHEN Fu-qiang, YANG Guang-hua, ZHANG Yu-cheng, et al. Discussion on value of coefficient in structural design of circular diaphragm wall[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(S0): 203-206. (in Chinese))  沈 健, 王卫东, 翁其平. 圆形基坑地下连续墙受力方法研究[J]. 岩土工程学报, 2008, 28(增刊): 280-285. (SHEN Jian, WANG Wei-dong, WENG Qi-ping. Study on analysis method of diaphragm wall of circular excavation[J]. Chinese Journal of Geotechnical Engineering, 2008, 28(S0): 280-285. (in Chinese))  刘明虎. 圆形地下连续堵支护深基坑结构受力特点及对比分析[J]. 公路交通科技, 2005, 22(11): 96-99. (LIU Ming-hu. Structural performance of the deep foundation pit bracing with circular diaphragm wall[J]. Journal of Highway and Transportation Research and Development, 2005, 22(11): 96-99. (in Chinese))  王 琨, 张太科, 陈顺超. 广州珠江黄埔大桥悬索桥锚碇基坑支护受力和变形特性分析[J]. 西南大学学报(自然科学版), 2010, 32(7): 133-138. (WANG Kun, ZHANG Tai-ke, CHEN Shun-chao. Force and deformation analysis of the retain structure for anchorage foundation pit of huangpu suspension bridge over Zhujiang Rive[J]. Journal of Southwest University(Natural Science Edition), 2010, 32(7): 133-138. (in Chinese))  黄海云, 朱宪辉. 圆形支护体系的实测数据分析与研究[J]. 岩土工程学报, 2006, 28(增刊): 1821-1825. (HUANG Hai-yun, ZHU Xian-hui. Researches on monitoring data of circle shape supports[J]. Chinese Journal of Geotechnical Engineering, 2006, 28(S0): 1821-1825. (in Chinese))  刘春原, 蔡伟红, 赵志斌, 等. 圆形地下连续墙的变形分析[J]. 岩土工程学报, 2008, 30(增刊): 26-30. (LIU Chun-yuan, CAI Wei-hong, ZHAO Zhi-bin, et al. Distortion analysis of circular diaphragm walls[J]. Chinese Journal of Geotechnical Engineering, 2008, 30(S0): 26-30. (in Chinese))