黏土中桩身表面粗糙度对单桩承载特性影响的试验研究

为研究预制桩桩身表面粗糙度和桩端条件对单桩承载特性的影响,预制了6种不同桩身粗糙度的桩,在室内进行了黏土中纯摩擦桩和摩擦端承桩的试验。试验结果表明:预制桩在黏土层中桩身表面粗糙度越大,其极限承载力越高;相同粗糙度不同桩端条件的桩,在荷载较小时荷载-沉降曲线基本重合,随着荷载的增大,相同荷载下,摩擦端承桩的桩顶沉降量小于纯摩擦桩的桩顶沉降量;在桩端处纯摩擦桩的侧摩阻力急剧减小而摩擦端承桩的侧摩阻力有所增强,经对这种现象分析认为,在摩擦端承桩中桩端处土体有挤压效应而使此处的侧摩阻力增大,在纯摩桩中,桩端底部是空的,桩土在桩端处相互作用较小而导致此处侧摩阻力减小。

Experimental study on impact of surface roughness of pile body in clay on bearing capacity of single pile

In order to study the influence of the surface roughness of the prefabricated pile body and the pile tip conditions on the bearing characteristics of a single pile,6 kinds of piles with different body roughness were prefabricated,and the tests of pure friction piles and friction end bearing piles in clay were performed indoors.The test results show that the larger the surface roughness of the precast pile in the clay layer is,the higher its ultimate bearing capacity is;the piles with the same roughness and different pile tip conditions,the load-settling curves basically coincide when the load is small,and the pile top settlement of the friction end bearing pile is smaller than that of the pure friction pile under the same load;at the pile tip,the side friction of pile of the pure friction pile decreases sharply and the side friction of pile of the friction end bearing pile is slightly reinforced.According to the analysis of this phenomenon,it is believed that the soil at pile tip in the friction end bearing pile has a squeezing effect,which increases the side friction of pile here.In a pure friction pile,the bottom of the pile tip is empty,and the pile-soil interaction at the pile tip is relatively small,resulting in a reduction in side friction of pile here.