Seepage Models For Horizontal Well Flow In A Rock Aquifer

Just for its advantages, horizontal well technology and its research has been widely adopted in fields of underground engineering, submarine engineering, petroleum exploitation, pollutants repairing and hydrogeology engineering. Both tunnels and drainage roadway can be treated as horizontal well. Tunnels gushing and drainage roadway gushing problem is common in mining exploring and always bring in significant loss. Rock aquifer with the dept-dependent exponential decrease of hydraulic conductivity is widely distributed in nature. Therefore the research of tunnel and drainage roadway which located in rock aquifer possesses practical and theoretical guidance significance. Previous have done some research about tunnels gushing and drainage roadway gushing problem. And solutions are obtained for predicting tunnel water inflows and water head for the commonly observed case of an exponential decrease of hydraulic conductivity with depth in isotropic jointed rock mass. However, there is no research about how non-flow boundary influence the tunnel water inflows. What's more, the comparison between rock aquifer with the dept- exponential decrease of hydraulic conductivity and homogeneous rock aquifer is not sufficient.According to the angle between the constant water head boundary and non-flow boundary, analytical solution and finite-element solution are presented respectively. Effects of tunnel depth, non-flow and constant water head boundary boundary distance on predicted water inflow are discussed. For the finite-element solution, MATLAB is adopted for mesh and VB is used for calculation. Analyzing is given to the tunnel water inflows, depth of peak water inflows and enormous difference between the up and down water head. What's more a comparison about tunnel water inflow is given between heterogeneous and homogeneous rock aquifer. At last, two kinds of mathematical model are applied into Yalongjiang Secondary Hydropower Station, and hydraulic conductivity is obtained according to tunnel water inflow date.