四桩厚承台数值模拟与现场实测分析*
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王兵1，余奇异2，龚维明3，戴国亮3（1 路桥建设重庆丰涪高速公路发展有限公司， 重庆 401121；2 城市建设研究院， 北京 100120； 3 东南大学土木工程学院， 南京 210096）［摘要］乌江特大桥索塔基础采用4根直径4.0m的灌注桩，整体式矩形承台平面尺寸为20.0m×16.4m，厚7.5m。运用ABAQUS软件对乌江特大桥厚承台进行了数值模拟，研究了承台厚度、桩径、承台埋深对承台传力机理的影响，结果表明，厚承台的受力机理完全符合空间桁架模型，斜压杆由桩顶指向荷载作用处，底部混凝土充当拉杆。通过对承台内部应力传递时形成的“拱效应”的研究发现，承台厚度和桩径的增加对减小承台底部受拉是有利的，但这样会导致承台顶部所需的受压钢筋量增大；承台埋置深度对承台内部拉压应力传递的影响可以忽略不计。在数值模拟的基础上，对原位厚承台埋设了钢筋计测试元件并进行了现场实测，实测结果也基本验证了其空间桁架理论的正确性。［关键词］厚承台; 数值分析; 影响因素; 空间桁架理论; 现场实测中图分类号：TU473.1 文献标识码：A 文章编号：1002-848X(2013)19-0099-05Numerical analysis and field test of thick pile cap with four pilesWang Bing1, Yu Qiyi2, Gong Weiming3, Dai Guoliang3(1 Road & Bridge Construction of Chongqing Fengfu Expressway Development Co., Ltd., Chongqing 401121, China; 2 Urban Construction Design & Research Institute, Beijing 100120, China; 3 School of Civil Engineering, Southeast University, Nanjing 210096, China)Abstract: The foundation of the cable tower of Wujiang super bridge is made of four bored piles with diameter of 4.0m and the size of the rectangular pile cap is 20.0m×16.4m×7.5m. ABAQUS is used to carry out numerical analysis on the pile caps to research the effective factors as the thickness and buried depth of pile cap, and pile diameter. Results show that the stress mechanism of thick pile cap matches the spatial truss model in which the diagonal struts point from pile head to the loading point and the concrete under the cap acts as the tie. By studying the aching effect formed inside the pile cap when transferring the internal stress, the results show that the increment of the cap thickness and pile diameter help to reduce the tension under the pile cap while increase amount of bars on top the pile cap. The influence of the buried depth of pile caps on internal stress transfer can be ignored. Based on the numerical simulation, the rebar test elements were amounted to carried out field testing and the data verify its space truss theory.Keywords: thick pile cap; numerical simulation; effective factor; space truss theory; field testing*交通部西部交通建设科技项目（200331849457）和港珠澳大桥跨海集群工程建设关键技术研究与示范课题（2011BAG07B01）。作者简介：王兵，高级工程师，Email：576369756@qq.com。参考文献［1］郑颖人，龚晓南.岩土塑性力学基础［M］. 北京：中国建筑工业出版社，1989.［2］JTG D62—2004公路钢筋混凝土及预应力混凝土桥涵设计规范［S］. 北京：人民交通出版社，2004.［3］庄茁，由小川，廖剑晖，等.基于ABAQUS的有限元分析和应用［M］. 北京：清华大学出版社，2009.［4］卢建峰.桩基承台空间桁架理论设计方法研究［D］.南京：东南大学，2001.［5］郭宏磊，丁大钧.厚承台受力机理研究［J］. 郑州大学学报，2004,25（1）：22-44.［6］谷倩，朱向阳.六桩厚承台传力模式试验和有限元分析［J］.工业建筑，2007,37（3）：50-55.
