PHC-钢管组合桩高应变检测修正方法

Modification method for high strain test of PHC-steel compound piles

针对PHC-钢管组合桩这类非常规桩的极限承载力设计及高应变检测难题,开展了高应变试验和竖向静载试验。设计制作3根不同长度组合的PHC-钢管组合桩,采用锤击法沉桩,通过高应变现场试验和竖向静载试验,得出基于两种试验数据的极限承载力;依据高应变和竖向静载试验结果,通过理论分析提出了PHC-钢管组合桩高应变实测曲线拟合法的修正方法。结果表明,对于PHC-钢管组合桩,高应变实测曲线拟合法得到的极限承载力大于竖向静载试验下的极限承载力,提出的修正方法计算结果与竖向静载试验结果基本一致,可用于PHC-钢管组合桩极限承载力高应变法检测。

To solve the problem of the ultimate bearing capacity in design and the difficulty in high strain test for nontraditional PHC-steel compound （PSC） piles,high strain test and vertical static load test were carried out. Three PSCs made of PHC and steel piles were designed with different length ratios. Pile-sinking was performed using the hammering method, and the vertical bearing capacity of the PSC was obtained by in situ high strain test and vertical static load test. Then, a modification for the high strain measured curve fitting method was proposed by theoretical analysis. The results show that the vertical bearing capacity of the PSCs measured by the high strain measured curve fitting method is higher than that from the static load tests while the results computed by the proposed modification method were in consistent with the static load tests. Therefore, the modification method can be applied to the measurement of the vertical bearing capacity of the PSCs.