PHC管桩承载力的动力和静力测试对比分析

Comparative Analysis of Dynamic and Static Tests of Bearing Capacity of PHC Pipe Piles

预应力高强度混凝土(PHC)管桩是软土分布地区采用的重要桩型。通过对佛山市禅城地区某地块的工程桩进行了动力(高应变法)和静力(静载荷试验)测试,对比分析了PHC桩的动静两种测方法的单桩承载力、动静参数相互关系和测试误差。试验研究表明,动静两种测试方法的单桩竖向承载力相对误差为7.1%~25.2%。Capwap法的计算精度主要受桩土力学模型、桩土作用体系、岩土阻力的激发程度、拟合参数的选择等因素影响,合理的参数选择可有效提高该方法的精度。通过单桩静载荷试验的特征曲线分析,建立了弹性模量与应变的经验公式。本文研究成果可为类似工程的管桩设计和桩基动静检测提供参考依据。

Prestressed high-strength concrete pipe pile is an important pile type in soft soil areas.Some engineering piles were tested dynamic load(high-strain test)and static load(static load test)in Chancheng,Foshan City,and the dynamic and static test results of bearing capacity of PHC pipe piles,the relationship between dynamic and static parameters,and the test error were compared and analyzed.The results show that the relative error of the vertical bearing capacity of the two methods varies from 7.1%to 25.2%.The calculation degree of the Capwap method is mainly affected by the pile-soil mechanical model,the pile-soil interaction system,the excitation degree of the rock-soil resistance,and the selection of fitting parameters.Reasonable parameter selection can effectively improve the accuracy of the method.Several kinds of characteristic curves of single pile static load test are obtained,and the empirical formula of elastic modulus and strain was established.The comparison test results can provide a reference for the design of pipe piles and dynamic and static detection of pile foundations in the region.