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.