现浇X形桩成桩过程充盈系数研究

现浇X形桩具有节省混凝土用量、提高承载力的特点,但目前针对X形桩成桩质量检测的理论研究相对较少。基于保角变换将原物理平面上的X形桩孔映射到像平面的单位圆上,结合平面弹性力学的复变函数方法得到了均布内壁压力作用下X形桩孔边界位移解析解;利用得到的解析解建立了X形桩成桩过程充盈系数的计算方法;最后,与现场试验实测数据进行对比验证,结果一致。研究结果表明:本文建立的理论计算方法可以准确、有效地计算X形桩成桩过程充盈系数;X形桩凹弧长度随着内壁压力的增加而线性减小,充盈系数随着内壁压力的增加线性增大。

Research on Concrete Filling Index of a XCC Pile During Construction

X-section cast-in-place concrete (XCC) pile can save concrete usage and improve pile tip resistance. However, there are few studies about the theoretical methods of their quality during the construction. In this paper, the X-section hole in the original physical plane are mapped on the unit circle in the phase plane based on the conformal mapping technique, and the theoretical solutions of the X-cavity boundary value problems under uniform inner pressure calculated by plane complex variable elasticity method are obtained. Then, taking advantage of obtained closed-form solutions, the calculation method of the concrete filling index of the XCC pile during the construction is developed. Finally, the computed results are compared with the measured data in situ, showing reasonable agreement. The results show that the concrete filling index (CFI) of a XCC pile during the construction can be accurately and efficiently calculated by the theoretical method established in this paper. Also, the length of the cambered section of a XCC pile decreases linearly with the increase of inner pressure, and the concrete filling index increases linearly with the increase of inner pressure.