基于机器学习的盾构隧道地表沉降曲线智能预测方法

    Intelligent Prediction Method for Settlement Curves of Shield Tunnel Based on Machine Learning Algorithms

    • 摘要: 联合机器学习模型和启发式智能优化算法,提出盾构隧道开挖地表沉降曲线智能预测方法。首先,建立盾构隧道开挖数值分析模型,在考虑等代层弹性模量、土体弹性模量、隧道半径、土体摩擦角、黏聚力影响的基础上,构建了1 680组不同工况影响的地表沉降曲线数据库;然后,分析地层和衬砌力学参数、隧道几何参数对地表沉降曲线的影响规律,采用Peck函数对获得的地表沉降槽曲线进行拟合,获得对应工况下地表最大沉降和沉降槽宽度系数;最后,采用粒子群优化算法(particle swarm optimization, PSO)分别优化4种机器学习方法即多层感知机(multi-layer perceptron, MLP)、极限学习机(extreme learning machine, ELM)、随机森林(random forest, RF)和支持向量回归(support vector regression, SVR)的超参数或随机数,建立了4种盾构隧道开挖有限元模拟代理模型,预测了盾构隧道地表沉降曲线,并对模型的预测结果、预测误差和评价指标进行了对比分析,结果表明PSO-SVR模型在训练和测试过程中性能最佳。建立的盾构隧道地表沉降智能预测方法具有较高的计算精度及计算效率,能合理高效地预测地表沉降曲线分布规律。

       

      Abstract: This paper combines machine learning models and heuristic intelligent optimization algorithms to propose an intelligent prediction method for surface settlement curves during shield tunnel excavation. First, a numerical analysis model for shield tunnel excavation was established, taking the effects of equivalent layer elastic modulus, soil elastic modulus, tunnel radius, soil friction angle, and cohesion into account. A database of 1 680 surface settlement curves under different working conditions was constructed. Then, the influence of geological and lining mechanical parameters, as well as tunnel geometric parameters, on the surface settlement curves was analyzed. The Peck function was used to fit the obtained surface settlement trough curves, and the maximum surface settlements and settlement trough width coefficients under corresponding working conditions were obtained. Finally, the particle swarm optimization algorithm (PSO) was used to optimize the hyperparameters or random numbers of four machine learning methods, namely multi-layer perceptron (MLP), extreme learning machine (ELM), random forest (RF), and support vector regression (SVR). Four finite element simulation proxy models for shield tunnel excavation were established, and the surface settlement curves of the shield tunnel were predicted. The prediction results, prediction errors, and evaluation indexes of the models were compared and analyzed. Results indicate that the PSO-SVR model performs best during training and testing. The established intelligent prediction method for surface settlement of shield tunnels has high computational accuracy and efficiency, and can reasonably and efficiently predict the distribution pattern of surface settlement curves.

       

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