上海复兴东路越江隧道联络通道施工过程的三维有限元与智能分析

Temperature field and construction pre-control of a connection aisle between two tunnels in Shanghai by means of 3D FEM,neural networks and fuzzy logic

在上海复兴东路越江隧道进行联络通道施工时,位于浦东的上层联络通道布置了一部分倾斜冻结管进行了冻结法施工。用倾斜冻结管进行联络通道冻结法施工,目前还找不到成熟的理论来计算其温度场和应力场,但温度场和应力场的精确计算对确保联络通道施工的安全性和经济性非常重要,基于此,用三维有限元方法对温度场进行了计算模拟,然后与现场测试结果进行了对比,对比结果表明,有限元计算的温度场有很好的精度。又采用自行开发的自适应神经网络专家系统软件对温度场进行了预测,预测结果令人满意。选取最合理的模型参数值通常是很困难却又很重要的,研究温度场对计算参数的敏感性对获得合理的计算参数非常重要,为此,讨论了温度场对计算参数和相关指标的敏感性。最后,用模糊控制器给出了施工预控制方案。研究结果对隧道工程施工技术和冻结法施工技术的发展很有助益。

The freezing construction technique is one of the most effective and widely applied site construction methods in soft soil area,including in Shanghai.Some elevatlon-inclined refrigeration pipes are arranged for the artificial freezing excavation of the Pudong-side first-storey connection aisle,which is designed to connect two adjacent tunnel lanes of Shanghai East-Fuxing-Road tunnel project,No advanced research results could be found for computing the temperature and stress fields of tunnels and aisles frozen with inclined refrigeration pipes,But the relevant temperature and stress computation is really very important for the safe and economical excavation of the above-mentioned aisle.So, a method for computing the aisle temperature field using 3D FEM is given, and the computation accuracy is verified by contrasting the computed and site measured results.The BP （ back propagation ） neural networks are also applied to the temperature prediction using self-developed Neural Network-Expert System software, the predicted results are also very satisfactory.The mechanism during freezing and aisle excavation is also discussed on the basis of 3D FEM computation,Selecting the optimum values of model parameters are often very difficult and at the same time very important for obtaining the most accurate result.So ,the parameter-sensitivlty of temperature field is also discussed.In order to obtaining the optimum frozen wall thickness, the relation between the frozen wall thickness and the initial freezing brine temperature is studied,At the end, an excavation pre-control plan is proposed by means of fuzzy logic theory for improving the excavation safety,The research result is helpful for the projects ,which will be excavated by freezing construction technique.