无粘结钢绞线抗拔桩的承载性状和抗拔系数研究

无粘结钢绞线抗拔桩是一种桩身混凝土受压工作的新型抗拔桩。文中采用数值分析方法分析了砂土中无粘结钢绞线抗拔桩和普通抗拔桩的承载特性及其关系,探讨了桩-土参数对无粘结钢绞线抗拔桩的抗拔系数修正值的影响。结果表明,无粘结钢绞线抗拔桩的极限承载力大于同条件下的普通抗拔桩,桩身的压缩量小于普通抗拔桩的拉伸量。抗拔系数修正值随桩的长径比L/D、桩的泊松比ν_{p以及桩周土的平均剪切模量Gavg的增大而增大,并呈线性关系,与土的泊松比νs呈线性减小关系。最后给出了无粘结钢绞线抗拔桩抗拔系数的计算公式。}

Shaft Capacity and Tension Coefficient of Unbonded Steel Strand Uplift Pile

Unbonded steel strand uplift pile was a new type of shaft compressive uplift pile. An investigation of unbonded steel strand uplift pile in sand was undertaken through FE analysis to provide insight into the behaviour of this new pile. The relationship of pile and soil properties and effects on the revised pile resistance coefficient of unbonded steel strand uplift was discussed.The FE results confirmed that the lateral resistance capacity of unbonded steel strand uplift pile was greater than that of the traditional uplift pile, and the compressive deformation of pile shaft was less than the tensile deformation of traditional uplift pile.Revised tension coefficient increased linearly with length-diameter ratio L/D,the Poisson’s ratio of pile ν_{pand the average shear modulus of soil Gavg. The revised tension coefficient decreased linearly with Poisson’s ratio of soil νs.An empirical formula of the unbonded steel strand uplift pile’s tension coefficient is given, which will provide theoretical basis for engineering practice.}