The effect of cavity wall irregularities on seepage exclusion from horizontal cylindrical underground openings

We have extended a quasi-linear approach for two-dimensional unsaturated flow analysis of seepage exclusion from cylindrical underground cavities, in homogeneous porous media, to include the effect of cavity wall irregularity on the threshold percolation flux at which water first begins to drip into the opening. The analyses presented here are for irregularities described by a periodic undulation in the cavity wall and for a single angular pendant protruding from the cavity roof. Results from a semi-analytical solution of the quasi-linearized flow equation indicate that roof pendant features having a vertical scale approaching the inverse of the pore size distribution parameter, characterizing moisture retention of porous media, can reduce the threshold percolation flux by an order of magnitude.