Study of seepage parameters measured in water pressure test inside boreholes in cut-off wall
LI Bingwei1，2，WU Jichun2
(1. School of Earth Sciences and Engineering，Nanjing University，Nanjing，Jiangsu 210039，China；
2. Anhui Water Conservancy Technical College，Hefei，Anhui 230000，China)
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.
李炳蔚1，2，吴吉春1. 防渗墙钻孔压水试验渗流参数研究[J]. 岩石力学与工程学报, 2016, 35(2): 396-402.
LI Bingwei1，2，WU Jichun2. Study of seepage parameters measured in water pressure test inside boreholes in cut-off wall. , 2016, 35(2): 396-402.
2016, Vol. 35 
