文摘
A method is proposed for evaluating rock hydraulic conductivity (k x;y sub>, LT?) in grid model blocks to be used in finite-difference simulation of mass exchange in gypcified fractured-porous rocks containing groundwater. The values of k x sub> and k y sub> were determined taking into account the dominating form of transport (advection or transverse dispersion), contributing most to gypsum dissolution. The method was used to simulate groundwater flow in a vertical section of gypsified rocks in the base of the dam at the Lower-Kafirniganskii Hydropower System. The changes in rock permeability in the base of the dam were used to evaluate whether there is a need to take seepage-control measures (cement-grout curtain, blanket, and a gypsum fill over the blanket). A leaching zone was found to form near the curtain and blanket during the simulation period (100 years) under background seepage conditions. In this period, the total water flow in the lower pool can increase by no more than 10-5%. Under such conditions, the “seepage-control-measures can enhance the reliability of the dam at the Lower-Kafirniganskii Hydropower System.