• Tunnel and Underground Space
• /
• v.17 no.6
• /
• pp.493-502
• /
• 2007

Measurements of hydraulic conductivity are point or interval values, and are highly limited in their number. Meanwhile, results of geophysical prospecting can provide the information of spatial variation of geology, and abundant in number. In this study, it was aimed to develop a data integration tool for constructing a hydraulic conductivity map by integrating geophysical data and hydraulic conductivity measurements. The developed code employed a geostatistical optimization method, simulated annealing (SA), and consists of 4 distinct computation modules by which from exploratory data analysis to postprocessing of the simulation were processed. All these modules are equipped with Graphical User Interface (GUI). Validation of the developed code was evaluated in-situ in characterizing hydraulic characteristics of highly permeable fractured zone.

• Tunnel and Underground Space
• /
• v.15 no.2 s.55
• /
• pp.145-156
• /
• 2005

MODFLOW, 3-D finite difference code, is widely used to model groundwater flow and has been used to assess the effect of excavations on the groundwater system due to construction of subways and mountain tunnels. The results of numerical analysis depend on boundary conditions, initial conditions, conceptual models and hydrogeological properties. Therefore, its accuracy can only be enhanced using more realistic and field oriented input parameters. In this study, SA(simulated annealing) was used to integrate hydraulic conductivities from a few of injection tests with geophysical reference images. The realizations of hydraulic conductivity random field are obtained and then groundwater flows in each geostatistically equivalent media are analyzed with a numerical simulation. This approach can give probabilistic results of groundwater flow modeling considering the uncertainty of hydrogeological medium. In other words, this approach makes it possible to quantify the propagation of uncertainty of hydraulic conductivities into groundwater flow.