泥水盾构带压开舱时泥浆配制及泥膜形成实验研究

在水下盾构隧道的建设中难免会出现盾构停机进行开舱检修的情况,带压开舱是目前水下隧道开舱常用的方法之一。然而,如何调整泥浆使其在开挖面上形成泥膜对开挖面稳定更有利,是工程界极为关注的问题。结合南京长江隧道工程在砾砂地层中的带压开舱作业,开展泥浆配制及成膜实验研究。提出先以低密度、低黏度的泥浆形成渗透带,再以较高密度、高黏度的泥浆形成泥皮型泥膜的2步调整的泥浆方案,并在现场带压开舱作业中进行了应用,形成了气密性良好的泥膜,保障了开挖面的稳定,对今后类似的泥水盾构开舱时的泥浆配制有重要参考意义。

Experimental Study on Preparation and Filter Membrane Formation of Slurry during Hyperbaric Operation in Tunneling by Slurry Shield

During the construction of underwater tunnels, the boring of the shields has often to be stopped to check and repair the cutting tools under hyperbaric conditions. However, how to adjust the slurries to form a dense filter membrane on the excavation face so as to maintain the stability of the excavation face is still a problem to be solved. In the paper, experimental study is made on the preparation and filter membrane formation of slurries, with the hyperbaric operation of shield in gravel and sand strata during the construction of Nanjing Yangtze River Tunnel as an example. A series of tests are made on the preparation and filter membrane formation of different slurries. A two sep slurry adjustment program, i.e, firstly, slurry with low density and low viscosity is used to infiltrate into the sand strata, then slurry with large density and large viscosity is used to form a filter membrane on the excavation face, is proposed. The program proposed has been applied in the hyperbaric operation during the construction of Nanjing Yangtze River Tunnel, air tight filter membrane has been formed and the stability of the excavation face has been guaranteed. The experience can provide valuable reference for the slurry preparation in other similar projects.