地铁联络通道冻结壁冻融灾害效应及其平均温度预测

Disaster effect of freez-thaw on the frozen wall of subway connection channel and its average temperature prediction

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摘要冻结法因具有施工方便、强度高、防水效果好及对土体扰动小等优点在软土地区地铁联络通道施工中获得广泛应用。冻结壁平均温度作为衡量冻结效果的重要参数之一,其解析公式求解较为复杂,在实际工程中难以应用。建立了包括冻结管断裂灾害、隧道收敛变形灾害、冻结帷幕收敛变形灾害、冻结帷幕透水灾害和融沉灾害的地铁联络通道冻结壁冻融灾害链式效应机制,并考虑多种布管方案,采用冻结壁平均温度等效梯形法建立完整数据集,利用神经网络的高度非线性特征,建立能同时预测单排、双排和多排(n>3)布管形式下冻结壁平均温度的神经网络预测模型。研究结果表明,基于完整数据集构建的冻结壁平均温度神经网络预测模型能有效地反映不同冻结管布置参数和冻结壁厚度等参数与冻结壁平均温度之间的关系;冻结壁平均温度均随冻结管排数和冻结壁厚度增大而逐渐降低,随盐水温度、冻结管间距和排距增大而逐渐升高。 The ground freezing method has been increasingly applied to improve the properties of surrounding formations during the construction of tunnel connecting channels in soft soil areas,owing to the advantages of being easy to use,high reliability,good groundwater control,and small disturbance to the soil.The average temperature of the frozen wall,as one of the important parameters to measure the freezing quality,is quite difficult to be obtained due to its complicated solution procedure.In this paper,a chain effect mechanism of freez-thaw disasters on the frozen wall of the subway connection channel is established,including the fracture of frozen pipes,the convergent deformation of the frozen tunnel in the frozen area,the disaster of convergent deformation of the frozen curtain,the seepage of freezing curtain and the ground settlement during the melting of the ground frozen wall.Considering the layout of the freezing pipes,a complete data set is established by using the equivalent trapezoid method of the average temperature of frozen wall.Based on the highly nonlinear characteristics of the neural network,a general model for predicting the average temperature of the frozen wall is established when the freezing pipes are spaced in a single row,double rows,and multi-rows(n>3).The results show that the neural network prediction model based on the complete data set can effectively reflect the relationship between different freezing tube layout parameters,freezing wall thickness and freezing wall average temperature.The average freezing wall temperature decreased gradually with the increase of freezing tube row number and freezing wall thickness,but increased gradually with the increase of brine temperature,freezing tube spacing and row distance.

作者邹宝平牟军东罗战友邓沿生董涛范秀江易觉 ZOU Baoping;MOU Jundong;LUO Zhanyou;DENG Yansheng;DONG Tao;FAN Xiujiang;YI Jue(National Key Laboratory of Tunnel Engineering Disaster Prevention and Intelligent Construction and Maintenance,China University of Mining and Technology(Beijing),Beijing 100083,China;School of Civil Engineering and Architecture,Zhejiang University of Scence and Technology,Hangzhou 310023,China;Hangzhou Metro Group Co.,Ltd.,Hangzhou 310017,China;School of Civil Engineering,Tongji University,Shanghai 200092,China;China Tunnel Construction Group Co.,Ltd.,Guangdong,Guangzhou 510308,China;Zhejiang Jiantou Transportation Infrastructure Construction Group Co.,Ltd.,Hangzhou 310012,China)