坏损预应力管桩的修复及单桩承载力利用值的取值建议

Repair and Load Bearing Capacity of Damaged Prestressed Pipe Piles

在沿海,软土地基由于基坑支护的失效,预应力管桩发生偏位、倾斜和断桩的现象经常出现,能否对坏损预应力管桩通过处理后加以利用,是解决类似基础工程问题的关键。针对宁波某行政楼工程桩发生偏位的情况,分析Ⅲ,Ⅳ类桩的利用机理,确定坏损桩修复后单桩承载力利用值的取值原则。对于基坑内无法进行机械施工的区域,采用后补静压锚杆桩的逆作方法;对于基坑外的部分,采用钻孔灌注桩补桩。对修复后的预应力管桩和补桩进行静载荷检测确定其真实承载力,以确保整个建筑物桩基的安全。

Eccentricity and retaining is common in soft rupture of prestressed pipe piles resulted from the failure of foundation excavation ground foundation of coastland. The key solution of such problem is how to deal with the damaged piles. According the pile eccentricity appearing in an administration building in Ningbo city, based on analysis of working mechanism for piles of category Ⅲ and Ⅳ, principle of determination of load bearing capacity for ruptured piles was presented. In the region of no machine construction, reverse building method of filling static pressured anchor pile was adopted. Bore-hole cast-in-place pile was filled outside the foundation pit. To guarantee the safety of the total building piles, static load check-up was carried out to determine the real bearing capacity of the repaired and filled piles.