Abstract: In order to study the feasibility of fire smoke control in inclined tunnel by using environmental wind induced by stack effect, a systematic study on smoke flow distribution in inclined tunnel under the effect of environmental wind was carried out. The influence of stack effect caused by tunnel slope on smoke flow distribution in inclined tunnel is revealed, and the asymmetric flow effect of smoke in inclined tunnel under natural ventilation is analyzed. Result shows that as the elevation difference increases,the mass flow rate of smoke and air flowing in the positive direction increases from 50% to a value close to 100%, while that flowing in the negative direction decreases from 50% to a value close to 0%. By using elevation difference as the characteristic parameter, the empirical formula of mass flow rate of outflowing smoke and entraining air is presented. In addition, the prediction formula of maximum smoke back-layering length is proposed.

Key words: inclined tunnel, asymmetric flow, mass flow rate, back-layering length