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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。
Taking the N-line shield-belt open-clam shell of the Nanjing-Sanjiang cross-river passage as the engineering background, aiming at the destructive process of mud-shield of mud-water shield under the action of air pressure, the laboratory test was conducted with the on-site construction technology. Based on this, the particle flow method was used to simulate the failure process of the mud film considering the microscopic parameters such as shape and grading of the formation. The results show that the damage of mud membrane is caused by the tensile stress caused by air pressure, which causes the mud membrane to crack and breathe. When the pressure is less than 0.45 MPa, the failure time of the mud film decreases sharply with the increase of the pressure. When the pressure is greater than 0.45 MPa, the failure time of the mud film tends to be stable with the increase of the pressure. The corresponding research results can provide reference for engineering practice.