确定土体前期固结压力的非参数化拟合模型

Nonparametric fitting model for determining soil preconsolidation pressure

土体前期固结压力是判断土体固结状态的一个重要指标。对不同固结状态的土,其沉降计算公式不同,准确确定土体前期固结压力非常重要。在采用常规参数化模型进行e-lgp曲线拟合求解最大曲率点不完善的基础上,提出了非参数化模型——3次平滑样条曲线进行拟合的方法,计算表明:该模型对试验数据适应性好,拟合精度高。基于卡萨格兰德确定前期固结压力的方法,通过MATLAB语言编制了相应的计算程序PCP Calculation,程序界面友好,可准确绘制图形,计算结果令人满意。

Soil preconsolidation pressure is an important index for determining the consolidation status. The foundation settlement calculation formulas are different as on various consolidation statuses, so it is very significant to determining preconsolidation pressure precisely. First the imperfectness of normal parametric models for determining the max curvature point of the fitted e-lg（p） curve is analyzed; then the cubic smoothing spline which is a nonparametric model used for fitting is proposed; the calculation results show that this model is more adaptive to experimental data and the fitting result is more precise. Base on the Casagrande＇s method of determining the preconsolidation pressure, the corresponding program ＂PCP Calculation＂ is then developed by MATLAB; the program has a friendly interface and can draw figure exactly; and the calculated results are satisfactory.