| Summary: | 碩士 === 國立成功大學 === 資源工程學系碩博士班 === 101 === This study focused on two tunnels,Guanyin and Gufong which belong with the Improvement Program of Su-hua Highway. Accroding to topography,geological structure and hydrogeological information,building 3D hydrogeological conceptual model to assess the variation of inflow and the impact on adjacent hydrological environment under tunneling excavation.It may provides the engineering safety of tunnel building and environmental assessment.Detailed analysis and assessment of factors which may affect the hydrogeology and issues of inflow.To predict to reduce engineering disasters and the cost of difficult engineering,while achieving goal of sustainable management.
First,collecting and analyzing hydrological information to establish water balance model that contains rainfall data,evapotranspiration data and flow data.Annual groundwater recharge is about 62.34 cm/year and the groundwater recharge ratio is about 22.3% for study area.Then,collecting regional geology data,DTM(Digital Terrain Model) and hydrogeological parameters.Finally,using GMS(Groundwater Modeling System) analysis software,demarcation of the border based on the hydrogeological characteristics of the area.To import the above information respectively to build 3D hydrogeological conceptual model,analysis of changes in its inflow and flow field.
The simulation results show that the Guanyin tunnel has higher inflow which expressed approximately 1,950 L/min when meeting Zhengshushan fault and fracture zone,in marble zone expressed approximately 700 L/min and in Guanyin fault expressed approximately 550 L/min.Gufong tunnel has higher inflow which expressed approximately 1,350 L/min when meeting Guyin fault and Gufong fault ,in marble zone and fracture zone expressed approximately 850 L/min.
This study modified the formula from Goodman(1965) to forecast the inflow which are respectively 1477.77(L/min),171.05(L/min),158.00(L/min) and 742.36(L/min) when construction meet principle faults(Zhengshushan,Guanyin,Guyin and Gufong).Sensitivity analysis of inflow and hydraulic conductivity,indicated that when the hydraulic conductivity is higher ,the inflow will be higher.When the hydraulic conductivity reach a certain value,the inflow will slow down to increase.
Concerning the influence of inflow on regional groundwater recharge,total inflow quantity(without setting up concrete wall) in two tunnels is less than 0.71% of the average annual recharge of sum of 4316.2 million m3 for South Nanao stream and Heiping stream.With the viewpoint ,the effect of tunnel construction is minimal on the adjacent hydorological environment.
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