高水土压力下盾构刀盘安全性分析与降水方案研究

Safety Analysis and Reduce Water Measures of Shield Cutterhead under Large Depth and High Water Pressure

某引水隧道使用泥水盾构施工,隧道较长且隧道埋深大、水压高,为保证在大埋深、长距离掘进时刀盘结构的安全,采用经验公式计算出不同埋深的水土压力值,对掘进过程中面临的四种典型工况进行了刀盘的有限元强度分析;采用MSC Patran/Nastran软件得出了四种工况下刀盘结构的应力与位移并验证了数值解的正确性,找出刀盘结构的强度薄弱点,针对部分区域水土压力过大进行降水试验并制定了详尽的降水措施。结果表明:通过分析不同埋深、水压作用下刀盘的变形量,结果显示刀盘面板在承压1.4 MPa时已经达到最大值,刀盘在牛腿与前面板连接处最大应力为227 MPa,此时要采取措施降水压,降水措施可以满足施工安全要求;给施工提供技术参考,提高了刀盘掘进过程的整体安全可靠性,保证长距离掘进施工安全。

A draw water tunnel is constructed using slurry shields. The tunnel is long and the tunnel is deep and the water pressure is high. To ensure the safety of cutterhead structure in large buried depth and long-distance tunneling, the finite element strength analysis of cutterhead under four typical working conditions is carried out. Calculating the water and soil pressure of different buried depths by empirical formula, then the stress and displacement of the cutterhead structure under four working conditions are obtained by using MSC Patran/Nastran software, and the weak points of the cutterhead structure are found out. The results show that the deformation of cutterhead under different buried depth and water pressure has reached its maximum value at 1.4 MPa, and the maximum stress of cutter head at the joint of corbel and front panel is 227 MPa. At this time, measures should be taken to reduce the water pressure, and the precipitation measures can well meet the construction safety requirements. It can provide the technical reference for the construc-tion, improve the overall safety and reliability of the cutterhead tunneling process, and ensure the safety of long-distance tunneling construction.