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    基于大样本数值模拟与机器学习算法的机械化钻爆法隧道智能设计

    Intelligent Design for Mechanized Drilling and Blasting Tunnels Based on Massive Numerical Simulations and Machine Learning Algorithms

    • 摘要: 机械化钻爆法开挖隧道具有进尺长、台阶短、临空面大的特征,基于既有工程经验的隧道设计方法,难以适应机械化施工的需求.依托渝昆高铁隧道群,通过MATLAB随机生成符合现场实际的计算工况,调用有限差分软件FLAC3D开展大样本自动化数值模拟,并将结果保存至数据库中.引入机器学习算法,将初始地应力场、岩体物理力学参数、开挖支护参数作为输入层,将围岩变形及支护体系力学响应作为输出层,对径向基(RBF)神经网络进行训练,建立了输入层与输出层参数之间的非线性映射关系.利用遗传-模拟退火算法(GA-SA),开展隧道断面开挖和支护参数优选.结果表明,RBF神经网络的预测精度较高,其中二次衬砌拱顶轴力的拟合度R2为0.836.在迭代优化过程中调用训练完毕的神经网络,能够直接获取输入参数对应隧道断面的力学响应结果,显著节约了计算时间成本,使优化结果迅速收敛至最优适应度.

       

      Abstract: Mechanized drilling and blasting method has the characteristics of the long excavation length,short step,and large excavation face.Tunnel design methods,primarily reliant on the existing engineering experience,are difficult to meet the requirements of mechanized construction.Based on the tunnels located on Yukun high-speed railway,this paper randomly generated calculation cases that are consist with the actual conditions utilizing MATLAB.Massive automated numerical simulations were then conducted by the finite difference software FLAC3D.The results of which were stored in the database.The machine learning algorithms were introduced to establish a nonlinear relationship between the data in input and output layers of the trained RBF neural network.Where,the in-situ stress field,physical and mechanical parameters of the rock mass,excavation and supporting parameters were seen as the input data.Meanwhile the deformation of surrounding stratum and mechanical response of supporting systems were seen as the output data.The GA-SA algorithm was adopted to optimize the excavation and supporting parameters of a specific tunnel section.The results indicate that the RBF neural network has a high prediction accuracy with a determination coefficient (R2) of 0.836 for the axial force at the vault of the secondary lining.By repeatedly invoking the trained neural network during the iterative optimization process,the mechanical response related to the input data can be directly obtained.This methodology significantly reduces the computational time required for the numerical simulations,enabling the results to expeditiously converge to the optimal level.

       

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