Abstract:

Slurry shields have been widely used for the construction of rivercrossing tunnels. Because of the complexity of the strata, adjusting the parameters of the slurry timely and reasonably is of great importance for smooth tunneling. In this paper, taking Weisanlu Yangtze River Tunnel as the study background, the authors select four types of sand strata to make the slurry membrane test, so as to determine the density and viscosity of the slurry. Then, the authors use the waste slurry produced when the shield bores through the silty clay strata as the base material, add bentonite slurry or Type CYHS3 tackifier solution into the base material, and get the mixing proportions of slurries that can meet the requirements of the four types of strata. Conclusions drawn are as follows: 1) Slurry with its density being less than 1.05 g/cm3 is not suitable to form filter membrane in sandy strata; 2) Bentonite slurry and tackifier solution can adjust the viscosity of the slurry; 3) When the viscosity of the slurry is larger than 20 s, the bentonite slurry has obvious effect in adjusting the viscosity of the slurry; 4) The larger the slurry density, the better effect the tackifier solution has on the viscosity of the slurry; when the slurry density is less than 1.10 g/cm3, the tackifier solution has almost no effect on the viscosity of the slurry.

Key words: slurry shield, filter membrane formation, slurry preparation, density, viscosity, Weisanlu Yangtze River tunnel