Mechanical Analysis of Radon Transport in Vicinity of an Underground Tunnel

A radial symmetrical model of radon transport in vicinity of an underground tunnel is developed with continuum mechanics theory.Distribution of radon concentration in the vicinity of tunnel is analyzed under the assumption that only diffusion and permeation are considered.Analytic solutions are obtained.A rock mass range affecting the radon concentration in the tunnel is defined as effective transport distance.Effective transport distance as functions of effective porosity and velocity are given.Expressions of radon exhalation rate on tunnel wall are shown.