Shield cutter head tunnel face reinforcing method and grouting reinforcing device used for method

The invention provides a shield cutter head tunnel face reinforcing method and a grouting reinforcing device used for the method. The grouting method comprises the steps that a telescopic grouting device is installed at a reserved ball valve position at the position more than 9/half of a soil bin of a shield tunneling machine, and a grouting head is controlled by an oil cylinder to stretch into a soil layer close to a cutter head in the soil bin or stretch out of a cutter head gap to be arranged on a cutter head tunnel face for direct grouting; and the grouting slurry is prepared from sand, fly ash, bentonite, lime, cement, water and a modified additive according to a special proportion. The grouting device can be installed at the reserved position on the soil bin wall of the shield tunneling machine, grouting reinforcement is conducted on the tunnel face of the cutter head of the shield tunneling machine conveniently, rapidly and efficiently, the problems that the stratum reinforcement construction progress