Discussion on Calculation of the Prediction of the Discharge Rate of Karst Tunnel Gushing in Investigation Stage

The prediction of the discharge rate of karst tunnel gushing in investigation stage is the most difficult problem in the prediction of the discharge rate of tunnel gushing.The paper starts from the research state about karst tunnel gushing,in recent years,then,finds out some problems in the prediction of the discharge rate of karst tunnel gushing in investigation stage,and analyses their causations.Finally,summarizing some engineering examples,aquires a mathed for improving the pricision of the prediction of the discharge rate of karst tunnel +gushing in investigation stage.In order to explain it,the paper picks up an example specially.