Abstract: The primary waterproof can be realized by curtain pre-grouting of roadway, which will control the water burst before, during or after the driving from the water exit points that have hydraulic relation with the driving roadway.The permanent waterproof can be achieved by setting a rigid-flexible sealing layer behind the roadway wall.A mechanical model for water burst points is established based on the effective stress action principle of rock and soil, and the constitutive relation between hydrodynamic pressure and contact pressure of rock and soil is analyzed.It is found that the curtain pre-grouting process is one where the effective stress gradually increases while the pore water pressure gradually decreases to finally achieve a dynamic balance.When the effective stress and the gross stress reach a balance in grouting, the primary waterproof effect can be achieved.The lining of rigid-flexible sealing behind the roadway wall can increase the effective stress and reduce the pore water pressure so as to achieve a long-term waterproof effect.This provides a theoretical basis for permanent water blockage in tunneling.The monitoring and application results show that the theory of primary and permanent waterproof has provided an effective way for the waterproof in tunneling.

Key words: Roadway, Curtain grouting, Primary waterproof, Permanent waterproof