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i <br /> By applying the above boundary conditions, assuming ideal gas flow, and integrating to solve for <br /> 1P Ile pressure p(r), Darcy's law becomes: <br /> g g <br /> p(r) _ [p.= - q.TAp. / (19.88khTj In(r)r)]1/2 (3) <br /> where p(r) = pressure at a radius r, psi <br /> p, = pressure at outer boundary, psi <br /> q. = air extraction rate, cfd <br />' T = soil temperature, 515 °R <br /> T. = temperature at which q,. is measured, 520 T <br /> µ = air viscosity, 0.018 centipoise (cp) <br /> PV. = pressure at which q. is measured, 14 7 psia <br /> k = air permeability, darcy <br /> h = height of the extraction interval, ft. <br /> r, = radius of influence, ft. <br /> r = radius, ft. <br /> Equation (3) can be applied to the steady-state pressure responses observed in the field to <br /> calculate the soil transmissibility and radius of influence. - <br /> Estimates of transnussivities and radii of influence have been calculated for pairs of observation <br /> wells that meet the following criteria: <br /> 1. The distances of the two observation wells from the test wells should differ by a minimum <br /> of 10% <br />' 2. The difference in vacuum pressures between the two observation wells should be at least <br /> 0 3 in HZO, and the two observation well pressures should be non-zero. <br /> These conditions allow better definition of the vacuum gradient to the computation of the air <br /> transmissibility and the radius of influence. <br /> r <br /> P <br /> D-2 <br />