静钻根植桩竖向承载性能现场试验研究

Field tests on bearing capacity of pre-bored grouted planted piles under compression and tension

通过一组现场试验对同一场地内静钻根植桩的抗压和抗拔承载性能进行研究,试桩均加载至极限状态。通过抗压和抗拔静载试验对静钻根植桩的抗压和抗拔承载性能进行对比分析。试验结果表明:静钻根植桩的抗压承载性能相比传统钻孔灌注桩有显著提高,本次试验场地各土层中静钻根植桩的桩侧摩阻力是规范建议的钻孔灌注桩极限侧摩阻力的1.49~3.21倍;静钻根植桩抗拔承载性能也明显优于钻孔灌注桩,抗拔试桩的极限承载力是根据规范计算的钻孔灌注桩极限抗拔承载力的1.52~1.55倍;静钻根植桩抗拔状态下桩侧摩阻力明显小于抗压状态下的桩侧摩擦力,即静钻根植桩也存在侧阻抗拔系数。

A series of field tests are conducted to study the compressive and uplift bearing capacities of pre-bored grouted planted(PGP)piles in the same test site,and the test piles are all loaded to the ultimate state.The compression and uplift bearing capacities of the PGP piles are also compared based on the field test results.The test results show that the compressive bearing capacity of the PGP piles is significantly improved compared to that of the bored piles,and the ultimate skin friction of the PGP piles in different soil layers in this research is about 1.49~3.21 times the ultimate skin friction of the bored piles recommended by the local specification.The uplift bearing capacity of the PGP piles is also better than that of the bored piles,and the ultimate skin friction of the PGP piles under tension is 1.52~1.55 times that of the bored piles under tension recommended by the local specification.Moreover,the ultimate skin friction of the PGP piles under compression is obviously smaller than that under tension,and the uplift coefficient of skin friction is also needed for the PGP piles.