黏弹性地基中楔形桩水平振动特性研究

为完善楔形桩的水平振动理论以便更好地使用,基于Timoshenko梁模型,研究黏弹性地基中水平简谐激振力作用下的楔形桩水平振动问题。首先,分别采用Winkler地基模型和Timoshenko梁模型模拟黏弹性地基和楔形桩,建立楔形桩-土系统横向耦合振动模型。进一步采用分离变量法和传递矩阵法推导得到楔形桩桩身水平位移、弯矩和剪力的解析表达式,并基于所得解详细讨论桩土设计参数对楔形桩空间响应和时间响应的影响。最后,将本文解与Euler梁模型的解进行比较,分析两种模型解的差异。结果表明:桩顶部的动力响应受楔角改变的影响很小;整个桩体的动力响应基本随桩土刚度比的增大而明显增大;随着无量纲频率的增大,桩身水平位移逐渐减小;虽然Timoshenko梁模型与Euler梁模型在小长径比下存在一定差异,楔角对两种模型造成的影响基本相同。

Horizontal vibration characteristics of tapered pile embedded in viscoelastic foundation

To improve the horizontal vibration theory of tapered pile for better use, based on the Timoshenko beam model, the horizontal vibration problem of tapered pile embedded in viscoelastic foundation subjected to horizontal harmonic excitations was investigated. First, the Winkler foundation model and Timoshenko beam model were used to simulate the viscoelastic foundation and tapered pile, and the lateral coupling vibration model of pile-soil system was established. Then, the analytical expressions for the horizontal displacement, bending moment, and shear force of the tapered pile were derived by means of variable separation method and transfer matrix method. The influence of the design parameters of pile-soil system on the horizontal vibration characteristics of tapered pile was analyzed based on the obtained solutions. Finally, the results were verified by comparing with the Euler beam model solutions, and the difference between the solutions of the two models was analyzed. Research results show that the dynamic response of the pile top was little affected by the variation of the wedge angle. The dynamic response of the whole pile increased with the increase of the pile-soil stiffness ratio. With the increase of the dimensionless frequency, the horizontal displacement of the pile decreased gradually. Although there were differences between Timoshenko beam model and Euler beam model under small length-diameter ratio, wedge angle had basically the same effect on these two models.