(厦门理工学院， 厦门 361024)

［摘要］提出在桩顶（坑底）位置处设置钢筋计测试下部桩身抗拔承载力的钢筋应力测试法试桩，采用有限元软件ABAQUS对4类试桩（常规试桩、钢筋应力测试法试桩、套管试桩及坑底试桩）开展数值分析，总结不同试桩下抗拔桩荷载传递规律及其工作机理。在此基础上采用所提出的钢筋应力测试法试桩在不同有效桩长及开挖深度下进行抗拔桩承载性能分析，结果表明：抗拔桩有效桩长越长，与坑底试桩抗拔桩极限承载力相比，基坑底面处钢筋拉力的损失比例越小；随着开挖深度的加大，与开挖后抗拔桩承载力相比，测试得到的钢筋拉力的损失比基本在10%～15%范围变化。在实际工程应用中，建议可按所提出的钢筋应力测试法测试抗拔桩下部桩身承载力，考虑开挖的影响，按10%～15%来折减抗拔桩的极限承载力。

［关键词］抗拔桩； 超深开挖； 承载力损失比； 有限元法

中图分类号：TU3755文献标识码：A文章编号：1002-848X(2015)11-0081-06

Bearing behavior analysis and design method study on uplift pile under deep excavation condition

Wu Yibin

(Xiamen University of Technology, Xiamen 361024, China)

Abstract:A reinforcement stress test method in pile test was presented with reinforcement meter set at the top of the pile (bottom of foundation pit) to test the lower pile uplift bearing capacity. Using the finite element software ABAQUS, numerical analyses of 4 kinds of pile tests were carried out including conventional pile test,  reinforcement stress test method  in pile test, casing pipe pile test and pile test at the  bottom of foundation pit. The load transfer rule and working mechanism of uplift pipe in different pile tests were summarized. On this basis, the proposed reinforcement stress test method in pile test was used in  bearing performance analyses of uplift piles with different effective pile lengths and excavation depths. Results show that the longer is effective length of uplift pile, the smaller is reinforcement tension loss ratio of bottom pile compared with ultimate bearing capacity of uplift pile in pile test at bottom of foundation pit. With the increase of the excavation depth, compared with the  bearing capacity of uplift pile after excavation, obtained reinforcement tension loss ratio changes basically in scope of 10% to 15%. In the actual project application, suggestions were provided that bearing capacity of bottom uplift pile could be tested by the proposed reinforcement stress test method, and the ultimate bearing capacity of uplift pile should be reduced by10% to 15%.

Keywords:uplift pile; deep excavation; loss ratio of bearing capacity; FEM

*上海市青年科技“扬帆计划”科研课题项目（14YF1414800），上海市人才发展资金计划资助项目（2014031），上海市科研计划课题项目(1104H105000)。

作者简介：吴毅彬，博士，Email: 53686090@qq.com。

参考文献

［1］黄茂松，郦建俊，王卫东，等. 开挖条件下抗拔桩的承载力损失比分析［J］.岩土工程学报,2008,30(9): 1291-1297.

［2］黄茂松，任青，王卫东，等. 深层开挖条件下抗拔桩极限承载力分析［［J］.岩土工程学报，2007，29(11): 1689-1695.

［3］陈锦剑，王建华，范巍，等. 抗拔桩在大面积深开挖过程中的受力特性分析［J］.岩土工程学报，2009，31(3): 402-407.

［4］郑刚，刁钰，吴宏伟. 超深开挖对单桩的竖向荷载传递及沉降的影响机理有限元分析［J］.岩土工程学报，2009，31(6): 937-845.