Fig. 13 shows the vertical temperature distribution below the shaft. The tendency of vertical temperature below the shaft is similar under different HRRs, however, the strong environmental wind affects the temperature distribution below the shaft evidently. At 3 m/s, the temperature tends to keep unchanged (close to the ambient temperature, 20 °C) with increasing the height, indicating that the plug-holing phenomenon occurs. Above 3 m/s, the temperature below the shaft tends to increase with increasing the height above a certain height (2.5–3.5 m), and the temperature increases even more under a higher wind speed, indirectly proving that a stronger wind blocks the smoke exhaust through the shaft more severely, thus more smoke with more heat exists under the shaft and less smoke with less heat can be exhausted, as also demonstrated in Figs. 11 and 12. Further, whether the plug-holing phenomenon occurs depends on the strength of the stack effect induced by the hot smoke inside the shaft. The reason why the plug-holing phenomenon does not occur in cases with a higher wind speed is the stronger blocking effect of the wind on the smoke plume, which restricts the circulating process of the smoke through the shaft. It also can be found from Figs. 8 and 9 that the flow velocity inside the shaft decreases with increasing the wind speed above the shaft.