软土地区大直径超长桩承载性状研究*
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（1 天津大学土木工程系， 天津 300072； 2 中交一航局第四工程有限公司， 天津 300456；3 天津市地下铁道集团有限公司， 天津 300000）
［摘要］基于3根桩端和桩侧后注浆的大直径超长桩破坏性试桩试验，对超长桩的桩顶荷载桩顶沉降特性、桩身侧阻力及端阻力的发挥特性等进行了分析。结果表明，在桩身完整和桩底沉渣较小的情况下，超长桩加载到一定荷载水平时仍然可能发生陡降式破坏。在承载力特征值作用下，超长桩承载特性可以认为是纯摩擦桩。由于超长桩桩身压缩量较大，桩身侧阻力由上向下逐步发挥。超长桩侧阻力软化现象主要发生在桩身中上部侧阻力发挥较早的部分，桩身下部侧阻力发挥较晚而未发现侧阻力软化现象。［关键词］软土地区; 超长桩; 承载特性; 破坏性试桩试验中图分类号：TU473 文献标识码：A 文章编号：1002-848X(2015)21-0074-05
Bearing characteristics study on large diameter super-long piles in soft soil areaGuo Yibin1, Zhao Guangmin2, Zhang Liming3, Xu Zemin3(1 Department of Civil Engineering, Tianjin University, Tianjin 300072, China; 2 No. 4 Engineering Company Ltd. of CCCC First Harbor Engineering Company Ltd., Tianjin 300456, China; 3 Tianjin Metro Group Co., Ltd., Tianjin 300000, China)Abstract: Based on destructive pile tests of three large diameter super-long piles with shaft and end post grouting, pile tip load-pile tip settlement characteristics, playing characteristics of shaft resistance and tip resistance were analyzed. Results show that steep drop failure may happen in super-long piles with well stake body integrity and small sediment in pile bottom when the loads reach certain level. Bearing characteristics of super-long piles can be considered asfriction piles under the bearing capacity characteristic value actions. The shaft resistance of super-long piles mobilizes from pile top to bottom due to largecompression of pile body. Shaft resistance degradation phenomenon of super-long piles is discovered in the upper part of the super-long pile which the shaftresistance mobilizes earlier, and that is not discovered in the lower part of the piles which the shaft resistance mobilizes relatively late.Keywords: soft soil area; super-long pile; bearing characteristic; destructive pile test
*国家重点基础研究发展计划（973计划）资助项目（2010CB732106），天津市建委科技项目（2014-9）。作者简介：郭一斌，博士，讲师，Email: 259582620@qq.com。
