深厚软土区桩柱式桥墩临界荷载简化计算方法

Simplified Calculation Method for Critical Load of Pile Piers in Deep Soft Soil Regions

现有桩柱式桥墩临界荷载简化计算方法在大多数情况下计算误差较大,适用性有限.在利用软土区现场桩基屈曲实验结果标定的基础上,采用基于特征值屈曲分析的有限元方法对有典型桩柱式桥墩的临界荷载进行了计算并与现有简化计算方法结果进行了对比,指出了现有简化计算方法的适用范围,发现现有简化方法不适用于软土区桩柱式桥墩计算.在大量桩柱式桥墩有限元特征值屈曲分析数据的基础上,采用随机森林算法对计算结果进行分析,得到可以计算桩柱式桥墩计算长度的随机森林模型以及各影响参数重要性指数分析结果.最后以现常用简化公式为基本形式,纳入随机森林算法给出的重要参数,通过回归分析,提出了深厚软土区桩柱式桥墩临界荷载的简化计算方法.

Existing simplified calculation methods for critical load of pile piers in bridge structures exhibit significant errors in most cases,limiting their applicability.Based on calibration using field load tests on pile foundations in soft soil regions,a finite element method based on eigenvalue buckling analysis was employed to calculate the critical load of typical pile piers and compared with the results obtained from existing simplified calculation methods.The study identified the applicability range of the existing simplified calculation methods and found that they are not suitable for calculating pile piers in soft soil regions.Using a large dataset of finite element eigenvalue buckling analysis results for pile piers,the random forest algorithm was applied to analyze the calculation results,yielding a random forest model capable of calculating the length of pile piers and determining the importance index of various influencing parameters.Finally,based on the form of commonly used simplified calculation formulas and incorporating the important parameters identified by the random forest algorithm,a simplified calculation method for determining the critical load of pile piers in deeply soft soil regions was proposed through regression analysis.