深厚软土地层超长超大直径扩底桩承载力性状及机理研究  

Study on Bearing Capacity and Mechanism of Super-long and Large Diameter Belled Pile in Deep Soft Soil Area

作　　者：莫成 岳琪迪 刘昭 周浩 MO Cheng;YUE Qidi;LIU Zhao;ZHOU Hao(South China Engineering Corporation of China Railway No.5 Engineering Group Co.,Ltd.,Dongguan 523160,China;China Railway No.5 Engineering Group Co.,Ltd.,Changsha 410007,China)

机构地区：[1]中铁五局集团华南工程有限责任公司,广东东莞523160 [2]中铁五局集团有限公司,长沙410007

出　　处：《广东土木与建筑》2023年第3期30-35,共6页Guangdong Architecture Civil Engineering

基　　金：中国铁路总公司科技研究开发计划重点课题(2017G007-D、2017G008-J);中国中铁股份有限公司科技研究开发计划重点课题(202011,202112)。

摘　　要：深厚软土地区超长超大直径扩底桩荷载传递机理复杂,且国内相关工程数量少,可供施工人员参考资料有限,传统桩基理论已无法合理的分析其工作机理和受力特性。文章依托深圳大运枢纽超长超大直径扩底桩工程,通过现场静载试验与数值仿真分析,研究了在深厚软土地层中超长超大直径扩底桩在静载作用下的荷载传递机理及沉降规律。基于荷载传递法,针对深厚软土地基的特殊性质,考虑了桩侧土初始剪应力、软化特性以及桩端土加工硬化特性,进行了沉降公式的推导。并基于MATLAB,开发了高性能的迭代算法以研究单桩的承载力性状。结果表明:现场试验、数值模拟与理论算法得到的荷载-沉降曲线线型吻合较好。当传递深度达到约0.4倍桩长时,下部桩身基本不产生压缩变形;桩基极限承载力大于设计值,存在较大的承载潜力,桩基设计较合理,满足承载力要求,可以为同类地区桩基工程设计与施工提供参考。As the load transfer mechanism of the super-long and large-diameter belled pile is complicated,there are seldom related projects in China.The reference files are limited and the traditional theory cannot analyze the working mechanism and bearing capacity of the super-long and large-diameter belled pile foundation reasonably.Based on the project of the super-long and large-diameter belled pile in Shenzhen Dayun junction center station,the load transfer mechanism and settlement law of the super-long and large-diameter belled pile are studied through on-site static load test and numerical simulation.Considering the deep soft soil,the initial shearing stress and softening behavior of the pile lateral soil,and the hardening behavior of the pile end soils,the settle formula of the belled pile is derived through the load transfer method.What’s more,the superior iterative algorithm for the calculation of the bearing capacity is developed based on the Matlab software.The results show that:the predicted load-settlement curves agree well with those from on-site tests and numerical simulation.When the transfer depth reaches 0.4 times of the pile length,the below pile does not cause compressive deformation.The ultimate bearing capacity is larger than the design value,which meets the basic requirements and provides some references for future projects.

关 键 词：超长超大直径扩底桩 深厚软土 沉降规律 静载试验 数值仿真 荷载传递法 

分 类 号：TU473.1[建筑科学—结构工程]