Abstract: In this paper, the stateofart and existing problems of waterproofing and drainage of composite lining tunnel are analyzed. And then the grading of control values of drainage volume and water pressure, separated waterproofing and drainage system, waterproofing capacity of surrounding rocks, and the integral waterproofing effect of waterproof layer and secondary lining concrete are studied. Finally, some suggestions in terms of design and parameters selection for waterproofing and drainage system are proposed as follows: (1) For the composite lining tunnel without special environmental and functional requirements, the drainage volume of the whole tunnel should be controlled within 1.0 m3/（m·d）, and the maximum water pressure behind secondary lining should be controlled within 1.0 MPa. (2) In order to reduce the occurrence of water leakage and guarantee the tunnel structural safety, the drainage system of arch and sidewall and that of invert should be separately arranged. The seeping water from arch and sidewall can be drained from side ditch, and that from invert can be drained from longitudinal central drainage dead pipe. When the water pressure is high, the water can be drained from longitudinal central drainage dead pipe to additional side ditch by horizontal drainage pipe, and the water drainage volume can be controlled by valve on horizontal drainage pipe. (3) By adopting measures such as ground separation wall(secant pile), surface grouting, grouting in tunnel, jet grouting, advance pipe roof, advance pipe curtain, doublelayer lining, etc., the water leakage can be reduced or even sealed, so as to guarantee the ground strength and integrity, reduce the water inrush volume and water pressure behind lining, and further reduce the adverse influence of water drainage of tunnel on operation and environment.

Key words: composite lining tunnel, waterproofing and drainage, waterproof layer, waterproof concrete, drainage volume, water pressure