泥水盾构泥膜破坏实验及颗粒流数值模拟研究

摘要

In the engineering background of the cabin opening under pressure of the Nth line shield of the underwater tunnel on Wei San Lu,Nanjing,and according to the failure process of filter-cake of the slurry shield under air pressure,laboratory experiments were carried out based on the construction technology on site.On this basis,the failure process of filter-cake is being simulated and analyzed by the method of particle flow code,which needs to consider the meso-mechanical parameters of the particle shape and size.The result shows: the failure of the filter-cake is due to the fact that the tensile stress in the filter-cake caused by the air pressure leads to the cracking of the filter-cake and then the air leakage of the filter-cake.Considering the critical point of 0.45 MPa,when the air pressure is less than 0.45 MPa,the destructive stability time decreases rapidly with increasing of the pressure.However,when the pressure greater than 0.45 MPa,the destructive stability time trends to be stable.The research results can provide valuable references for the practical engineering.%以南京纬三路过江通道N线盾构带压开舱为工程背景,针对泥水盾构泥膜在气压荷载作用下破坏过程,结合现场施工工艺,进行了室内试验的分析研究.在此基础上利用颗粒流方法,考虑了地层颗粒形状、级配等细观参数,对泥膜破坏过程进行了模拟分析.结果表明:泥膜破坏是因为在气压作用下产生拉应力导致泥膜开裂透气.以0.45 MPa为节点,气压小于0.45 MPa时,随着气压的增加泥膜破坏稳定时间急剧减小;气压值大于0.45 MPa时,随着气压的增加泥膜破坏时间趋于稳定.相应研究结果可为工程实践提供参考.