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水平桩的p–y曲线大多是基于试验数据(A P I规范,双曲线),旨在从理论出发推导桩侧土体的p–y曲线。首先,推导了与上限解等价的分步弹性加载理论,并结合刚性圆盘在环状弹性介质中受水平力作用下的弹性力学解以研究桩身水平位移和桩周平均剪应变间的关系;再应用该平均剪应变和土体的双曲线应力应变关系建立联系以得到桩周土体在加载过程中的平均屈服应力即已发挥的土体强度;以此确立二维情况下桩身位移和桩周土反力的关系即p–y骨干曲线。再进一步根据三维的桩侧初始地基模量和桩侧极限承载力,将其推广至三维。该p–y曲线的优点在于可以考虑土体应力应变关系、桩身刚度和长细比对p–y曲线的影响。最后,将本文p–y曲线和传统p–y曲线分别与工程实例以及有限元结果进行对比,并指出传统p–y曲线的不足及恰当的使用范围。
The p-y curves of horizontal piles are mostly based on experimental data (A P I gauge, hyperbola) and are intended to derive the p-y curve of the pile-side soil from the theory. First of all, the staged elastic loading theory equivalent to the upper bound solution is deduced, and the elastic mechanics solution of the rigid disc under cyclic force in a ring-like elastic medium is studied to study the relationship between the horizontal displacement of pile and the average shear strain The relationship between the average shear strain and the hyperbolic stress-strain relationship of the soil body is established to obtain the average yield stress of the soil around the pile body during the loading process, ie the strength of the soil body that has already been exerted; thus, the pile body Displacement and the reaction of the soil around the pile p-y backbone curve. Further, according to the three-dimensional pile-side initial foundations modulus and the ultimate bearing capacity of pile, it is extended to three-dimensional. The p-y curve has the advantage of considering the influence of soil stress-strain relationship, pile stiffness and slenderness ratio on the p-y curve. Finally, this paper p-y curve and the traditional p-y curve were compared with the engineering examples and the finite element results, and pointed out the lack of the traditional p-y curve and the appropriate range of use.