论文部分内容阅读
软弱土及湿陷性黄土等地区桩基负摩阻力计算是桩基础设计与施工必须考虑的问题之一,目前针对群桩负摩阻力计算方面的研究相对较少。采用有效应力法计算单桩负摩阻力,基于极限平衡原理计算负摩阻力群桩效应系数,从而得到群桩负摩阻力计算公式。结合现场试验结果,对现浇X形桩群桩负摩阻力及桩身下拽力进行计算分析,并讨论了群桩基础中各基桩位置对桩身下拽力的影响,以及群桩效应系数随相关影响因素的变化规律。研究结果表明,文中计算结果与现场实测结果具有良好的一致性;地面堆载等级越高,群桩所受的桩身下拽力越大,且群桩效应系数随着桩间距的增大而增大,随着负摩阻力系数和中性点深度比的增大而减小。
The calculation of negative skin friction of pile foundation in soft soil and collapsible loess area is one of the problems that must be considered in the design and construction of pile foundation. At present, the research on the calculation of negative skin friction of pile group is relatively few. The effective stress method is used to calculate the negative skin friction of single pile and the negative skin friction coefficient is calculated based on the principle of limit equilibrium. Combined with field test results, the negative friction and piled drag force of cast-in-situ X-shaped pile group are calculated and analyzed, and the influence of each pile position on the pile’s drag force is discussed, as well as the pile group effect Variation of coefficient with related factors. The results show that the calculated results are in good agreement with the measured data in the field. The higher the ground loading level, the greater the drag force is, and the pile group effect coefficient increases with the pile spacing Increase, decrease with the increase of negative friction coefficient and neutral depth ratio.