基于桩土位移协调的柔性桩荷载传递机理研究

基于桩土的位移协调,通过引进并加以改进的Alamgir位移模式和弹性理论分析柔性桩的荷载传递.根据桩侧摩阻力在桩顶以下1/3有效桩长处达到最大的条件,推导出有效桩长的计算式,进一步获得柔性桩的桩身应力、桩侧摩阻力的简化计算式.通过实例分析,验证计算公式的合理性.结果表明:桩侧摩阻力理论值与试验实测值相差较大,但沿桩长的分布二者较一致;桩身应力理论值与试验实测值吻合非常好;有效桩长理论值非常接近实测桩身应力几乎为0的深度.因此,推导出的柔性桩的桩身应力、桩侧摩阻力和有效桩长的计算方法具有一定的工程参考价值.

Investigation of mechanism of load transfer of deformable piles based on pile-soil displacement coordination

Based on pile-soil displacement coordination,the load transfer of deformable piles was analyzed with elastic theory and Alamgir displacement mode,which was introduced in this paper and improved.According to the condition,that the maximal skin friction on pile was located at the point of one third of its effective length below its top,a computation formula of effective pile length was derived and further the simplified formulas of stress in deformable pile and skin friction on such pile were obtained.The rationality of these formulas were verified by analyzing a practical engineering case.It was found that the difference of theoretical value of skin friction on pile from that of actual measurement of test were comparatively large,but the distribution of skin friction along the pile was in agreement.The stress in pile was in perfect agreement.The theoretical value of effective pile length was approximate to the depth at which the stress in pile was almost vanished in the test.So the derived computation method of effective length of deformable pile,stress,and skin friction would have a certain reference value for engineering practice.