不同桩头约束下微倾单桩纵横向受荷响应计算的三参数法

Three-parameter method for slightly inclined single pile with partial pile head fixity under combined vertical and lateral loads

为研究桩头转动约束及桩身初始微倾斜对纵横向组合荷载作用下桩身侧向响应的影响,基于三参数形式的地基水平抗力系数,通过矩阵运算提出了桩身变形和内力的半解析解,并与模型试验结果及已有解计算结果进行对比以验证其可靠性。计算结果表明:桩头转动刚度增加时,桩顶位移和地表以下桩身最大弯矩减小,桩顶弯矩和地表以下桩身最大弯矩距离桩顶的距离增大。桩身初始倾角增加时,桩身最大位移和最大弯矩均线性增大,且随纵向荷载的增加其变化速率逐渐增大;纵向荷载增加时,桩身最大位移和最大弯矩均增大,且随纵向荷载和桩身初始倾角的增加其变化速率逐渐增大,而地表以下桩身最大弯矩距离地表的距离呈线性减小。

In order to study the influences of the rotational restraint at pile head and the slight initial inclination of pile shaft on lateral pile responses under simultaneous vertical and lateral loads,semianalytical solutions were put forward by matrix calculation,based on the coefficient of subgrade reaction expressed in the three-parameter form.The results were validated by the comparison with model test results and the existing solutions.The results indicated that when the coefficient of rotational restraint at pile head increases,the displacement at pile head and the maximum bending moment under ground decrease,while the bending moment at pile head and the distance between the maximum bending moment under ground and pile head increased.Both the maximum displacement and bending moment increased linearly with the increase of the initial inclination angle of pile shaft,and their changing rates increasedwhen the vertical load increased.When the vertical load increased,the maximum displacement and bending moment increased,and their changing rates increased with increases of the vertical load and the initial inclination angle of pile shaft.The distance between the maximum bending moment under ground and ground decreased linearly when the vertical load increases.