Modflow and a moving tunnel face

[TOR23]

Hello all,
I am trying to construct a modflow model of an area to be tunneled at around 20 - 50 metres depth in a limestone / till terrane. The tunnel face and some shaft will be exposed before sealing. I am attempting to construct a modflow model with this migrating face. An objective would be to predict water generation potential of the exposed area as it migrates due to tunnel construction. Any tips/clues on how to do this would be greatly appreciated

 

[phillyfrank]

We did something similar a number of years ago using MODFLOW to predict coal mine inflow rates. We first modeled the excavation steps in a 2D finite element model (UTAH2) to get strains, which we then correlated to permeability enhancements around the excavation. We then used several steps of MODFLO to determine the flow rate at each excavation step. We published this in the 14th Annual Conference on Ground Control in Mining, West Virginia University, 1995, p. 252-260, "Application of Mechanical and Groundwater-Flow Models to Predict the Hydrogeologic Effects of longwall Subsidence -- A Case Study," D. Van Roosendaal, F. S. Kendorski, and J. Padgett. If you do not have access to this publication I can send you a copy if interested. frankatagapito@aol.com You may also wish to contact Derek Elsworth at Penn State who has done extensive research in this field. elsworth@psu.edu