Auger Hole Seepage Theory

Abstract

Abstract We solve the problem of water flow into a soil cavity, as an auger hole or any cylindrically shaped hole, e.g., a vertical root hole or a large circular pit, in a surrounding water‐saturated, homogeneous, porous medium. We consider the top boundary of the saturated flow medium to be a water table, with the assumption that drawdown of the water table about the auger hole during flow is small. We consider flow when (i) there is an impermeable barrier at a finite distance below the auger hole and (ii) there is an artesian source at a finite distance below the auger hole. By letting the finite distance become large in (i) and (ii) we solve the problem of a finite auger hole in a medium of infinite depth. The analysis yields, both for finite depth of soil below the auger hole and infinite depth of soil below the auger hole, a table of shape factors C . When a shape factor C is multiplied by an observed rate of rise of water in the hole, the multiplication gives the hydraulic conductivity of the soil. We compare our work, when applicable, with that of others. Our C values agree in the main with earlier C values for their limited range.