大连太平湾工程大直径灌注桩后压浆技术的应用

The Application of Post-grouting Technique to Large-diameter Cast-in-situ Piles of Dalian Taiping Bay Project

近年来,钻孔灌注桩后压浆技术在工程中已被大量应用。通过工程实例,对比普通灌注桩和采用后压浆技术的灌注桩的静载试验结果,着重分析后压浆技术对大直径钻孔灌注桩承载性能的影响;结合超声波无损检测技术的试验结果,探索后压浆技术对桩身完整性的影响;通过对后压浆技术的工作机理和施工工艺的介绍,为后压浆技术在工程中的应用提供指导。研究表明:采用后压浆技术的钻孔灌注桩桩身无明显缺陷,单桩极限承载力得到大幅度提高,并且可以有效避免施工中容易出现的桩底沉渣厚、桩壁土体松软等问题。

In recent years,post-grouting technique for the drilling piles has been applied substantially to engineering constructions. Based on an actual engineering project,the results of static tests on ordinary drilling piles and the drilling piles using post-grouting technique were compared,and the effect of post-grouting technique on the bearing capacity of large diameter drilling piles were analyzed emphatically. Then,according to the test results of utrasonic harmless detection,the effect of post-grouting technique on the integrity of the pile body was studied. After that,the working mechanism and the construction techniques of the post-grouting technique were introduced to provide guidance for its application to engineering. The study results indicate that with the application of post-grouting technique,the drilling pile has no obvious defect over the body,the ultimate bearing capacity of a single pile increases considerably,and the common problems in conventional constructions,such as the thick sediment at the pile bottom or soft soil around the pile lining,can be avoided effectively.