Abstract��
A model test was performed to study the effects of the cutterhead aperture ratio on the main shield driv? ing parameters during shield tunnel construction. Rules of pressure variations induced by different aperture ratios of the shield cutterhead inside and outside of the earth chamber were analyzed based on the monitoring of pressure changes and the transfer and distribution of soil pressures at the panel of the earth chamber under different aperture ratios of the cutterhead. Pressure differences at the work face and earth chamber panel were discussed, correlation formulas were established based on viscous fluid mechanics and a brief analysis of the influential factors of the pressure difference inside and outside of the earth chamber is conducted; the influence of the cutterhead aperture ratio on the squeezing effect and torque of the cutterhead was discussed and two kinds of squeezing effect mechanisms were presented. The test results show that the squeezing effect induced only by the cutterhead thrust occupies about 70% of the total squeezing effect, and the squeezing effect induced by cutterhead rotation occupies about 30% of the total squeezing effect. The relationship of the aperture ratio, torque of the cutterhead and the squeezing effect was systematically analyzed.
2017, Vol. 54 