人工挖孔桩水平裂缝的检测、处理与防治

Detection,Treatment and Prevention of Horizontal Cracks in Manually Dug Concrete Caissons

近年来,人工挖孔桩采用低应变检测时陆续发现桩身出现水平裂缝,在进行初步判断后,通过钻芯法进行验证,验证结果进一步确认了水平裂缝的存在。通过研究项目所处环境、地质条件、施工工艺等原因,分析人工挖孔桩水平裂缝的形成机理。通过试验总结了一套切实可行的高压注浆方案,对桩身水平裂缝进行加固、处理,注浆后采用低应变进行复检,检测结果未发现缺陷信号,表明处理效果显著。在此基础上提出人工挖孔桩避免产生水平裂缝的预防措施,应用此措施可极大减少处理费用,缩短了检测和工程处理的周期。

The low strain integrity test has been applied to detect horizontal cracks in concrete piles in recent years.After the preliminary examination by low strain tests,the horizontal cracks in the pile were confirmed by the coring.The factors that could result in the horizontal cracks are investigated based through the investigation of pile location,subsurface conditions,construction technique.The practical pressurized grouting for the horizontal crack mitigations was proposed and implemented and the integrity test on the treated piles could not detect the crack signal indicating a significant improvement of the defected pile.This paper also presents the measures that could reduce the horizontal cracks in the manually dug concrete caissons and the caisson treatment cost could therefore be reduced significantly.