PIT仪测试桩基结构完整性的波形判读方法

Judgment of structural integrity of pile foundation based on the wave pattern obtained by using Pile Integrity Tester

由于受多种因素的影响,混凝土钻孔灌注桩结构完整性检测的波形曲线有时比较复杂,难以准确判读。在大量现场实测的基础上,总结了PIT仪检测桩基结构各类缺陷的反射波形特征,指出波形判读应在桩体应力波传播反射理论的基础上,综合分析以确定缺陷类型。文章对桩周土阻力、嵌岩桩底端岩性及桩顶浅部缺陷引起的波形特征变化进行了分析,并给出判读方法。

WTThe obtained wave patterns in detecting the structural integrity of the concrete cast-in-situ bored piles are sometimes very complicated due to many influencing factors,which makes it difficult to judge pile integrity. In this paper, based on a large amount of on-the-spot detecting data,the features of reflection waves corresponding to various kinds of structural defects detected by the Pile Integrity Tester are summarized,and it is pointed out that the types of defects should be judged through comprehensive analysis according to the stress wave transmission and reflection theory. Also analyzed are the changes of the features of the wave pattern which are caused by the soil resistance around the pile,the different lithologic condition at the end of the embedded pile,and the defects at the shallow depth of the pile,and the corresponding ways of judgment given.