基于TCN-LSTM-Attention模型的TBM掘进速度预测

    Prediction of TBM tunneling speed based on TCN-LSTM-Attention model

    • 摘要: 为了更准确地预测隧道掘进机(TBM)的掘进速度(PR),在分析常见机器学习模型优劣的基础上,提出了一种基于时空特征提取的TCN-LSTM-Attention模型。首先利用孤立森林(IF)和集合经验模态分解(EEMD)对TBM掘进的原始数据进行预处理,剔除异常值并消除高频噪声;其次使用时序卷积神经网络(TCN)提取空间特征,再利用长短期记忆网络(LSTM)提取时间特征;最后通过注意力机制(Attention)对时空特征进行加权,实现非线性关系的精准拟合。实例应用表明:①与未经处理的数据相比,经过IF和EEMD预处理后,模型预测性能显著提升,在Ⅱ、Ⅲa、Ⅲb、Ⅳ、Ⅴ级围岩中,其决定系数(R2)分别提高了47.69%,43.77%,42.79%,42.25%和36.88%;②所提出的模型在各级围岩上的预测精度均优于RF、SVR和LSTM等模型,并且注意力机制能有效提升模型性能;③注意力权重分析显示,时空上相近的历史信息对未来信息的预测具有更大的影响;④在各级围岩组合的数据集中,该模型同样取得了较好的表现,均方误差(MSE)为3.743 3 (mm/min)2R2为96.22%。

       

      Abstract: In order to predict the TBM tunneling speed more accurately, based on the analysis of advantages and disadvantages of common machine learning models, this paper proposed a TCN-LSTM-Attention model based on spatio-temporal feature extraction. Firstly, the original data were preprocessed by using isolated forest (IF) and ensemble empirical mode decomposition (EEMD) to eliminate outliers and high-frequency noise. Secondly, the temporal convolutional neural network (TCN) was used to extract spatial features, and then the long short-term memory network (LSTM) was used to extract temporal features. Finally, the spatio-temporal features were weighted by the attention mechanism to realize the accurate fitting of the nonlinear relationship. The engineering application results showed that: ① Compared with the untreated data, the performance of the model was significantly improved after data pretreatment by IF and EEMD, for the Ⅱ, Ⅲa, Ⅲb, Ⅳ and Ⅴ grade surrounding rocks, the determination coefficient (R2) of the model was increased by 47.69 %, 43.77 %, 42.79 %, 42.25 % and 36.88 % respectively. ② The prediction accuracy of the proposed model on all levels of surrounding rock was better than that of RF, SVR and LSTM, and the attention mechanism can effectively improve the model performance. ③ Attention weight analysis showed that similar historical information in time and space had a greater impact on the prediction of future information. ④ In the data set of surrounding rock combination at all levels, the model also achieved good performance, with mean square error (MSE) of 3.743 3 (mm/min)2 and R2 of 96.22 %.

       

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