The construction parameters of slurry shield in tunnel construction are mostly adjusted according to the field construction experience

and the systematic theoretical calculation model between the construction parameters and mud pressure of slurry shield is lacking. The relationship that each construction parameter needs to be met during the process of shield tunneling has been put forward through a detailed research and analysis on the type and working principle of slurry balance shield. The slurry pressure control model of the slurry chamber of the slurry shield and the calculation method of the directly quantified controllable construction parameters of the slurry shield to control the mud pressure are obtained. The requirement that the mud residue suspension and transportation capacity in shield construction of the slurry pressure in the slurry chamber needs to be met has been presented and the relationship between the tunneling speed of the slurry shield and the slurry flow is deduced. The result shows that the slurry pressure of the slurry chamber increases with the increases of the slurry flow and the shield tunneling speed

and decreases with the increase of slurry discharge flow. The effectiveness of the presented calculation model is verified through the slurry shield construction project in Changsha subway line 6 and numerical simulation. The research result provides a theoretical basis for the study on slurry pressure control in slurry chamber of slurry balance shield.