泥水盾构泥膜动态形成机制研究

随着大直径泥水盾构的广泛应用,盾构掘进过程切削成层土的可能性越来越大,常规的静力平衡的方法不能有效地控制开挖面的稳定。从泥膜形成的机制入手,将泥水仓中的泥浆视为由液相和颗粒相组成的两相流,将开挖地层视为多孔介质,利用多相流在多孔介质中的渗流特性提出了泥膜动态形成的过滤模型。此模型将泥膜视为控制体,并认为泥膜形成过程中遵守质量守恒和体积守恒定律,从边界条件上认为单位时间内从单元体内排出水量与土体积的压缩量相等。过滤模型较好地揭示了泥水盾构掘进过程中泥膜的动态形成过程和开挖地层力学性质的动态变化过程,对泥水盾构正面稳定有较为重要的意义。

Research on dynamic formation mechanism of slurry membrane for slurry shield

With the rapid development of large diameter slurry tunnels, the possibility of cutting different strata during tunneling becomes higher and higher. So the method used to control the face stability exceeds the normal static method’s cover. Based on mechanism of membrane formation, a filtration model is introduced to simulate the slurry membrane during slurry shield tunneling. In filtration model, the slurry is regarded as multiphase flow, while the stratum as porous medium. By control volume method, during the formation of membrane, it complies with mass and volume conservation. When it comes to the boundary condition, the output volume of filtration is equal to the compression of soil. This model reveals the dynamic formation process of slurry membrane and mechanism changes of the stratum, which is very important to the face stability during slurry shield tunneling.