Research and Practice of Full Plugging Groundwater Technology in Water-Rich TBM Diversion Tunnel

To solve the problem of water discharge in the tunnel when the tunnel passes through the low-pressure water-rich fractured stratum, the grouting plugging technology of the low-pressure water-rich tunnel is studied. The grouting plugging scheme is optimized through the field test. The post-validation research is numerically simulated and the parameters of the complete sealing grouting ring are analyzed. The results show that: 1) Full plugging grouting can effectively improve the funnel effect of precipitation with good water plugging effect. With the decrease of the permeability coefficient and the increase of the thickness of the grouting ring, the flow velocity around the tunnel and the water discharge in the tunnel both decreased significantly, with a trend of "rapidly decreasing-slowly decreasing". Considering various factors, an optimal grouting ring thickness between 1.5 m and 2.5 m and a reasonable range for permeability coefficient between 2.07 × 10−6 cm/s and 4.14 × 10−6 cm/s are considered appropriate. 2) The use of cement-water glass system full plugging grouting for water plugging, can significantly reduce the discharge of water, only partial dripping or even dripping state. Using polyurethane foam single point method to systematically block grouting and water plugging can only changes the discharge path and hardly attenuates water discharge.