盾构下穿既有隧道扰动预测模型及掘进参数优化

    Prediction Model for Disturbance Induced by Shield Tunneling Underneath Existing Tunnels and Optimization of Tunneling Parameters

    • 摘要: 为解决盾构下穿高速铁路隧道变形超限引起既有隧道结构损坏及高速铁路行车安全问题,精确预测盾构隧道开挖引起上覆隧道最大变形至关重要。本研究基于盾构下穿既有隧道扰动变形多源异构数据库,通过XGBoost、支持向量机、神经网络机器学习算法构建了适用于新建盾构下穿施工诱发上覆高铁隧道变形的通用预测模型。基于依托工程案例,使用XGBoost算法对盾构下穿高铁隧道诱发沉降开展建模预测,借助Bayesian算法实现模型超参数优化,基于高铁隧道沉降限值提出盾构下穿施工的掘进参数建议范围。研究结果表明:(1)采用贝叶斯优化的XGBoost模型建立盾构穿越诱发既有隧道扰动预测代理模型,该模型预测误差95%以上小于0.65mm,决定系数R²达0.997,明显优于支持向量机与神经网络模型;(2)将预测代理模型与粒子群优化算法结合,建立盾构掘进速度、刀盘转速、同步注浆压力与同步注浆量为决策变量的优化控制模型,对盾构下穿浏阳河隧道段实施掘进参数优化并指导施工,无砟轨道结构沉降最大值为1.12mm,满足轨道变形控制标准;(3)盾构掘进参数优化后的高铁隧道沉降预测值与现场监测值的时程变化规律一致,最大偏差0.198mm,验证了盾构下穿既有隧道扰动预测与掘进参数优化控制方法的实用性与准确性。研究结果可进一步指导盾构下穿高铁隧道掘进参数范围拟定,并为保障高铁安全运营提供理论参考。

       

      Abstract: To address the issues of structural damage to existing tunnels and operational safety risks of high-speed railways caused by excessive deformation of high-speed railway tunnels due to shield tunneling underneath, accurate prediction of the maximum deformation of overlying tunnels induced by shield tunnel excavation is crucial. Based on a multi-source heterogeneous database of disturbance deformation from shield tunneling underneath existing tunnels, this study constructed a general prediction model for deformation of overlying high-speed railway tunnels induced by new shield tunneling underneath using machine learning algorithms including XGBoost, support vector machine (SVM), and neural network.Taking the project case as the research object, the XGBoost algorithm was used to model and predict the settlement of high-speed railway tunnels induced by shield tunneling underneath. Bayesian algorithm was employed to optimize the model hyperparameters, and the recommended range of tunneling parameters for shield tunneling underneath was proposed based on the settlement limits of high-speed railway tunnels.The results show that: (1) The XGBoost model optimized by Bayesian algorithm was used to establish a surrogate model for predicting disturbance of existing tunnels induced by shield tunneling. Over 95% of the prediction errors of this model are less than 0.65 mm, with the coefficient of determination (R²) reaching 0.997, which is significantly better than the SVM and neural network models. (2) By combining the prediction surrogate model with the particle swarm optimization (PSO) algorithm, an optimization control model with decision variables including shield tunneling speed, cutter head rotation speed, synchronous grouting pressure, and synchronous grouting volume was established. The optimization of tunneling parameters was implemented for the shield tunneling section underneath the Liuyang River Tunnel to guide construction, and the maximum settlement of the ballastless track structure was 1.12 mm, meeting the track deformation control standards. (3) The temporal variation law of the predicted settlement values of the high-speed railway tunnel after optimization of shield tunneling parameters is consistent with that of on-site monitoring values, with a maximum deviation of 0.198 mm, verifying the practicability and accuracy of the disturbance prediction and tunneling parameter optimization control method for shield tunneling underneath existing tunnels. The research results can further guide the determination of the range of tunneling parameters for shield tunneling underneath high-speed railway tunnels and provide a theoretical reference for ensuring the safe operation of high-speed railways.

       

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