Study on lining external water pressure under limited discharge in deep buried tunnel

Lining external water pressure under limited discharge in deep buried tunnel is studied in the paper by means of theoretical derivation of tunnel discharge and lining water pressure model. It is proved that lining upper water pressure decreases along with the increase of discharge after adopting drainage measures, but the lining upper water pressure increases little with the increase of cementing scope when the permeability coefficient of grout drop below 1.65×10-6m/s and the grout thickness reach 55cm, which shows that there should be a reasonable scope for cementing. Grouting can control the discharge of tunnel. Grouting area can be defined when the reasonable discharge from a passage tunnel are given.