Method for determining reasonable discharging quantity of tunnel underground water

The invention discloses a method for determining the reasonable discharging quantity of tunnel underground water. The method comprises the following steps that: (1) firstly, a tunnel waterproof and water discharge type is selected, wherein the tunnel waterproof and water discharge type is one type from a fully sealed waterproof type, a semi-sealed waterproof type or a discharge control mode waterproof and water discharge type; (2) the tunnel total water inflow in the tunnel waterproof and water discharge type selected in the first step is determined; (3) the ecological water demand of vegetational communities in a tunnel site region is determined; and (4) the underground water discharging quantity is determined according to the tunnel total water inflow and the ecological water demand determined in the second step and the third step. The method for determining the reasonable discharging quantity of the tunnel underground water has the advantages that the underground water discharging quantity is reasonably quantized in theory; the structure safety and the durability of a rich-water tunnel are improved; and measures are provided for protecting the ecological environment in the rich-water tunnel site region.