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| Bearing behaviors of self-balanced pile |
| XU Chang-jie, LI Bi-qing, CAI Yuan-qiang |
| MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China |
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Abstract Comparative tests of the six compressive test piles of a project in Hangzhou were taken by static load test and self-balanced test. The distribution properties of Q-s curves, axial force, side friction and other factors of the piles under self-balanced test were analyzed and compared to the static load test. The test results indicate that the force characteristics of the piles by two methods are different. The side friction begins to exert from down to up with selfbalanced test, which exerts oppositely with static load test. The reduction factor of sandy soil, clay and gravel could be 0.688, 0.774 and 0.860. For the soil in this project, the side friction reduction factor of self-balanced test could be 0.782. The Q-s curve conversed from self-balanced test is much smoother than static load test. When the loading level is low, there is distinguished difference between the converted Q-s curves with self-balanced test and the Q-s curves with static load test. The two Q-s curves tend to be similar with the heightening of loading level, which shows the reliability of self-balanced test．
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Published: 01 July 2012
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自平衡法试桩的承载特性试验研究
通过分别采用自平衡法试桩和静载法试桩对杭州市某工程6根抗压试桩进行对比测试,分析基桩在自平衡法试桩条件下的Q-s曲线、桩身轴力、侧摩阻力等分布规律,并与静载法试桩条件下桩身受力性状进行对比研究.研究结果表明：自平衡法试桩上部桩与静载法试桩的桩身受力特性差别较大.前者桩侧摩阻力由下及上发挥,后者桩侧摩阻力由上及下发挥.砂性土、黏性土及圆砾的侧摩阻力折减系数可取0.688、0.774、0.860.在本工程土质情况下,自平衡法试桩的侧摩阻力折减系数可取0.782.自平衡法试桩的经转换后的Q-s曲线较平滑,且在加载值较小时与静载法试桩的Q-s曲线有一定差异,但随着加载值的增大,两者的曲线趋于一致,说明了自平衡法试桩的可靠性.
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