Study On Prediction And Forecast Of Water Yield In Jiufeng Mountain Tunnel

With the rapid development of the national economy, there are a large number of mountain railway tunnel constructions in China. Water burst, during the construction and operation of tunnel, is one of the most serious geo-disasters for the survey and design stage.Moreover, the tunnel water burst sections and water inflow volume prediction calculation is the key to the problem. At the same time, this problem is also a major research topic of scholars and experts around the world.This thesis is based on the QuzhouNingde railway construction.During the tunnel construction and survey of long-term monitoring, the basic data was collected in the areas of Jiufeng Mountain Tunnel, The hydrogeological conceptual model was established based on the study on the hydrogeological model, groundwater flow system model and the groundwater dynamic model of the Qu Ning railway super long tunnel, After that, each section normal water inflow volume and maximum inflow applicable formula is determined.Then,the hydrogeological conceptual model was transformed into the reasonable mathematical model of groundwater seepage. We established and calculation model and predict tunnel water inflow by using MODFLOW software. Finally, the calculation results are compared and analyzed to study the reason of the difference between the calculation results, determine and demonstrate the rationality of the calculation model of tunnel inflow prediction, and put forward the suggestions of engineering control measures.The numerical simulation method for calculation of Jiufeng Mountain tunnel water inflow 35484m3/d, unit length maximum gushing water for 1236.2 m3/d.According to the comparative analysis of numerical calculation results and theoretical analysis of the calculation results, it can be observed that the MODFLOW software can effectively predict the tunnel water inflow.At the entrance and exit,and shallow buried section of the tunnel,the groundwater dynamic analytic method and numerical simulation method can be used to predict tunnel of normal discharge. The ground water dynamic analysis method can be used to predict the maximum gushing water in tunnel.At the deep seasonal variation section,the numerical simulation model can be suggested to use for the prediction of tunnel water inflow.