基于CTNOA-SBL-MIC模型的长桩桩端阻力预测分析

    Prediction of long pile tip resistance based on CTNOA-SBL-MIC model

    • 摘要: 机器学习(ML)已被广泛应用于桩基工程建模,然而由于桩体受载发生位移至一定程度时,桩端阻力才会变得显著,故预测长桩的桩端阻力通常具有挑战性。为准确预测长桩的桩端阻力,筛选出力学效应、桩体属性和土体特性3个关键方面的相关因素,提出一种结合多折交叉验证、混沌序列、星鸦搜索算法、稀疏贝叶斯算法和最大信息系数检验的混合模型框架,在提升预测准确性的同时增强模型的可解释性。选择越南胡志明市所采集的920个长桩和超长桩实测数据作为基准数据集,以均方根误差、平均绝对误差和相关系数作为模型预测准确性的指标。结果表明,所提模型在点预测方面都优于现有ML模型的预测,多种指标的值都接近最优。同时,计算了桩端阻力多种影响因子的相关性强度,结合现实工程经验极大丰富了关于模型内部计算的可解释性,对软土地基下长桩的设计和研究具有深远意义。

       

      Abstract: Machine learning (ML) has been widely used in pile foundation engineering modeling. However, predicting pile tip resistance of long piles remains a significant challenge, as pile tip resistance becomes substantial only when the pile is loaded and displaced to a certain extent. To address this issue and accurately predict pile tip resistance of long piles, three key factors—mechanical effects, pile properties, and soil properties—are identified. A novel hybrid modeling framework is proposed, combining multifold cross-validation, chaotic sequences, nutcracker optimization algorithm, sparse bayesian algorithm, and maximal information coefficient testing. This integrated approach not only improves prediction accuracy but also enhances model interpretability. The dataset, comprising 920 long and super-long piles, was collected in Ho Chi Minh City, Vietnam, and serves as the benchmark for this study. Model performance is evaluated using root mean square error (RMSE), mean absolute error (MAE), and correlation coefficient (R). The results demonstrate that the proposed model outperforms existing ML models in point prediction accuracy, with multiple evaluation metrics approaching optimal values. Furthermore, the paper calculates correlation strengths of various influencing factors on pile tip resistance, thereby significantly enhancing the interpretability of the model's internal calculations in combination with practical engineering insights. This study has significance for the design and research of long piles in soft ground conditions.

       

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