Hydrogeological modeling and groundwater inflow in tunneling

• Main Authors: Tzu-yangTai, 戴紫陽
• Other Authors: Cheng-Haw Lee
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/33532580755721574196

碩士 === 國立成功大學 === 資源工程學系 === 103 === This study focused on modelling and forecasting groundwater seepage during excavating in Guanyin tunnel, one tunnel in Improvement Program of Su-hua Highway. A 3D hydrogeological conceptual model was built by topography, geological structure and hydrological parameters to assess the groundwater seepage and the influence of groundwater level in tunnel excavation. Furthermore, the seepage data of each excavating step was applied to calibrate the hydraulic conductivity of rock mass along Guanyin tunnel in order to modify the numerical model and revise hydrological model in this area. Finally the numerical model was calibrated. The results showed that the variance of hydraulic conductivity in single metamorphic rock was about 4 orders and the density of fractures controlled the hydraulic conductivity of rock mass. The estimation of groundwater seepage in unexcavated area was still inaccurate because of the hydraulic parameters of rock mass was unknown. The statistics of seepage data was used to forecast the groundwater gush event which the seepage is more than 500 liter/minute. The results also shows that the occurring probability decreased when seepage increased and the average occurring distance of specific seepage could be calculated when expectation was 100%. The occurring distance in different seepage was applied to forecast the groundwater gush events in unexcavated area. One event located at the mileage 6k+100 in Guanying tunnel which the groundwater gush reached 1,500 liter/minute was predicted successfully.