基于Akima插值理论的水平试桩数据处理方法研究

Data processing method for laterally loaded trial piles based on Akima interpolation theory

在水平试桩数据处理过程中,经常会遇到低阶多项式拟合精度差、高阶多项式拟合不收敛以及五点滑移法数据点非等间距等问题,严重制约了试桩成果数据的进一步应用。针对上述难题,以Akima非线性插值理论为基础,对实测数据点进行分段拟合Akima非线性多项式,并推导得出相应的积分与微分表达式,进而建立基于Akima非线性插值理论的水平试桩数据处理方法。针对数据处理结果振荡问题,采用滤波方式予以解决。最后,通过柔性桩案例详细阐述了该数据处理方法的应用过程,结果表明该方法所得结果与理论计算结果几乎一致,验证了该数据处理方法的可靠性和实用性。该方法可为水平试桩数据处理难题提供新的解决途径。

A series of problems,such as low-order polynomial fitting with lower accuracy,high-order polynomial fitting with no convergence,five-point smoothing method countering unequally spaced data and so on,may occur in the data processing for laterally loaded trial piles,which impedes the application of the test data.To overcome the difficulties as discussed above,firstly,this work obtains Akima nonlinear polynomials for the measured data by the piecewise polynomial fitting technology on the basis of Akima nonlinear interpolation theory.Moreover,integral and difference expressions for the corresponding nonlinear polynomials are derived to establish the data processing method for laterally loaded trial piles based on the Akima interpolation theory.For the results oscillating from the data processing,the filtering method will be employed to deal with this issue.Finally,one case study for flexible piles is performed to illustrate the application of the proposed data processing method.Comparison shows that the results from proposed method are almost identical to those of theoretical calculation,which verifies the reliability and practicability of this new method.This study may provide a new approach to solve the difficulties in data processing for laterally loaded trial piles.