竖向荷载下刚性板桩筏基础分析方法

Analysis method of rigid piled raft foundation under vertical loading

根据群桩中桩侧摩阻力分布规律,在桩筏基础中基于弹性理论中的变形协调关系、桩体物理方程和力的平衡关系,推导了竖向荷载作用下桩筏基础的荷载和位移之间的刚度矩阵,从而提出了一种刚性板下桩筏基础的分析方法。刚性板桩筏基础分析中考虑了4种相互作用,分别为桩-土-桩、桩-土-板、板-土-桩和板-土-板相互作用。基础中各桩可具有不同的桩长、桩半径和刚度等特性。应用该方法不需要划分桩-土体单元,分析中的计算矩阵仅与基础中桩数和筏板下土节点数量相关而与其他变量无关,分析过程简洁通用。通过与各种分析方法的比较验证,证明该方法是合理可行的。

An analysis method of piled raft foundation with rigid cap is presented with the research results about allocation rhythm of side resistance in pile group. Based on displacement compatibility relationsliip, pile body stress and strain equation and force equilibrium relationship, stiffness matrix which relate top force to displacement is deduced. Four types of intreraction is considered herein, that is pile-soil-pile interaction, pile-soil-plate interaction, plate-soil-pile interaction and plate-soil-plate interaction. It is mentioned that pile group can be comprised of piles with the property of various lengths, radii and stiffnesses. The method does not involve the discretization of the soil or piles and it follows the same analysis process and the content of stiffness matrix is just related to the number of pile and soil nodes under foundation cap. Comparison with the results of other analysis methods shows that the method is feasible and accurate.