Radon transport in fractured porous media — Experimental study in caves

摘要: The spatial and temporal variation of 222Rn concentration in three horizontal caves one vertical cave was measured to study the influence different morphological meteorological parameters on forming airborne radon concentrations inside. In caves, daily mean as a function average surface temperature showed step-function type dependence with low winter high summer values reflecting main direction underground airflows. Restriction airflows increased but decreased levels. transition pattern between gradually linearized number fractures communicating increased. Contrary barometric pressure variations played most important role controlling subsurface concentrations. Decreasing levels, pressure-radon correlation curve, there small hysteresis which indicated nonlinearity process.