Abstract: Through the similar test, the relationship between the smoke stratification stability of highway tunnel fire and the power of fire source, the wind speed of opposite jet and the position of measuring point under the synergistic action of opposite jet and shaft was studied. Three kinds of 50 working conditions were designed, and the stratification stability of fire smoke at different locations under different working conditions was analyzed. The test results showed that the smaller the upstream and downstream wind speed difference is, the more stable the fire smoke stratification is, and the larger the upstream and downstream wind speed difference is, the more disordered the fire smoke layer is. When the wind speed of the opposite jet is the same, the power of the fire source has no obvious effect on the stratification stability of the fire smoke. Due to the interaction among thermal buoyancy, jet and shaft suction force, the stratification stability of fire smoke at different locations is different.

Key words: highway tunnel, shaft smoke exhaust, smoke layer stability, opposite jet