Hydraulic telescopic grouting device for reinforcing soil layer before shield opening

The utility model provides a hydraulic telescopic grouting device for reinforcing a soil layer before a shield is opened. The grouting device comprises a counter-force support, a grouting pipe, a telescopic oil cylinder and an oil cylinder fixing base, the counter-force support is fixed to a flange plate on the outer side of a reserved ball valve on the soil bin wall, and a grouting pipe penetrating hole matched with the grouting pipe is formed in the counter-force support; the oil cylinder fixing seat is an annular support and is fixedly arranged at the position, close to the grouting head, of the grouting pipe in a sleeving mode, the grouting head of the grouting pipe penetrates through a grouting pipe penetrating hole in the counter-force support and stretches into the inlet end of the reserved ball valve, and the telescopic oil cylinder is horizontally arranged between the oil cylinder fixing seat and the counter-force support and stretches to the maximum stroke. And one end of the telescopic oil cylinder