灌注桩复合缺陷的低应变反射波法检测实例分析

低应变反射波法较易判断桩顶以下首个缺陷,而当灌注桩存在复合缺陷时,因缺陷反射的叠加效应将导致其他缺陷难以识别甚至影响首个缺陷的判断。结合高桩码头灌注桩低应变反射波法检测实例,分析不同类型复合缺陷的反射波曲线特征,研究复合缺陷的识别和检测方法,并提出接桩、拔除外套筒、增加护筒长度及优化泥浆更新方法、凿除桩头等验证及处理措施。

Case analysis for detection of multiple defects in cast-in-place piles with low strain impact integrity testing

Low-strain impact integrity testing is capable to detect the first defect down from the pile head.However,when multiple defects exist in a cast-in-place pile,other defects are likely to be covered by the first one due to signal superimposed effect and even the reflected signal of the first defect may also be affected.Based on several pile integrity testing cases in open pile wharves with low-strain impact integrity testing,we analyze characteristics of the reflected signal related to different multiple defects,probe into relevant detection methods,and propose detection and treatment methods including pile splicing,outer steel casing extraction,depth increase of steel casing,optimization of mud circulation method,as well as cutting away of the pile segment.