施工因素对钻孔灌注桩受力性状的影响

INFLUENCE OF CONSTRUCTION FACTORS ON ENDURANCE OF BORED-CAST-IN-PLACE PILES

由于摩擦型钻孔灌注桩承载变形机理的复杂性,影响其承载性能的因素也是多方面的。通过对冲孔灌注桩和旋挖灌注桩的桩顶、桩端沉降量的静载试验资料及桩身应力应变测试资料的分析,揭示了不同施工工艺在不同荷载水平下桩的受力性状差异,并就影响桩侧摩阻力的因素进行了深入探讨。分析表明,施工造成的桩周土的性质,桩土相对位移,桩端沉渣,成孔时间,护壁清孔方式等因素的不同均会对单桩极限承载力产生重要影响。如果施工工艺选择不合理,单桩极限承载力会受到很大影响。

There are many factors which have a great impact on load-bearing capacity of piles because of the complex bearing-deformation mechanism.By analyzing the displacement of pile top and pile bottom of these piles,and analyzing the stress and strain of these piles,Influence of construction factors on endurance of these piles under different loading levels is revealed,and the factors which affect the side resistance also are further explored in this paper.Abnormal phenomena in ultimate bearing capacity of bored piles is mainly attributed to construction factors,such as soil characteristics,the relative displacement of pile and soil,pile bottom sediments,drilling tiem,bore retaining and cleaning,etc.The ultimate bearing capacity of bored piles can be greatly affected if construction technology is inappropriate.