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Abstract The permeability and permeability coefficient from water pressure test in boreholes are limited to the semi-infinite domain of rock. The cut-off wall is a strip domain，so it is clearly inappropriate to calculate the flow parameters using the equation for semi-infinite domain. The method of complex variable was used to transform the strip flow domain into the semi-infinite domain and permeability coefficient for strip domain was thus derived. The ratio Q?/Q of flux and k?/k of permeability coefficient for the semi-infinite and strip domains were analyzed. The influence of cut-off wall and drilling geometry L/r0 and r0 was discussed. When L/r0＜104.7，r0＜75 mm，k?= k or Q?=Q，the flux Q? and the water permeability q? in strip domain were greater than ones in the semi-infinite domain，namely Q?＞Q，q?＞q，and the permeability coefficient k?＜k. The conditions of seepage flow equation for cut-off wall measured with water pressure test in borehole were set according to the recharge boundary conditions on both sides of the strip domain and cut-off wall. Engineering examples showed that the calculated results with the proposed method agreed with the measured ones when the soil and the wall permeability ratio k1/k2＞100.
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2016, Vol. 35 
