To cut down the serious environmental problems caused by tunnel drainage with no control as possible

the waterproof criteria of “block off ground water and limiting discharge” that is controlled drainage should be adopted in mountain tunnels with high water level. But how is the mechanical character of the surrounding rock with controlled drainage? It is a key and urgent problem in tunnel design now. An analytical model is established for the first time to analyze the mechanical character of the surrounding rock with controlled drainage; and a series of equations are deduced. The variation of the mechanical character of the surrounding rock with controlled drainage is analyzed; and the corresponding ground reaction curves are drawn; this is a theory base for tunnel design with controlled drainage.