无粘结预应力抗拔桩预应力检测试验研究

Test study on construction inspection of unbounded pressing uplift cast-in-place pile

抗拔桩作为高层建筑的主要基础形式之一,对于建筑物的抗浮起着重要的作用。对于深大地下室而言,对单桩竖向抗拔承载力要求很高。普通抗拔桩为了控制裂缝,通常采用增加受拉钢筋的做法。此方式增加了抗拔桩的用钢量,经济性差。近几年有研究指出,在抗拔桩中使用预应力技术可有效控制桩身裂缝。通过使用无粘结钢绞线给桩身施加预应力,该技术在国内外鲜见应用,而抗拔桩作为建筑物的永久结构,其安全性至关重要。因此,无粘结预应力抗拔桩的施工和检测是保证桩基安全稳定的必要条件。鉴于此,对预应力抗拔桩钢绞线张拉过程进行检测,对不同阶段桩身受力状态进行分析,验证了预应力抗拔灌注桩施工工艺的有效性。

As one of the main foundation forms of high-rise buildings,Uplift piles play an important role in the anti floating of buildings.For deep and large basement,the requirements vertical uplift bearing capacity of single pile are very high.In order to control the cracks of ordinary uplift piles,tensile reinforcement is usually added.This method increases the steel content of uplift pile,which is not economical.In recent years,it has been pointed out that the use of pressed technology in uplift piles can effectively control pile shaft cracks.In this study,unbonded steel strands are used to prestress the pile shaft,this technology is rarely used at home and abroad.