It’s getting more and more common to

build infrastructures underground, which results in more people using underground facilities in their everyday life. The evacuation routes from this environment often involve long, ascending tunnels. In order to evaluate the evacuation time for these facilities, knowledge about people’s movement in this kind of environment is required. Today the knowledge within this area is limited, why new research within this field is needed.

The current study included two essential parts; 1) initial literature review where the state of the art within the current research field was mapped and 2) an experiment. The purpose of the experiment was to study people

’s walking speed and behaviour during ascending evacuation in inclined tunnels. The aim of the study was to develop data that can be used as basis for guidelines regarding fire safety design in major infrastructure projects and risk and safety assessment of underground facilities.

The experiment was carried out at the Äspö Hard Rock Laboratory in March 2018. In total 32 persons participated and they were asked to individually walk upwards 907 m in a tunnel with an inclination of 14 %. When walking in the tunnel, the participants

’ walking speed, vertical walking speed, pulse and rating of perceived exertion were documented. In addition to the individual tests in the tunnel, the experiment included reference tests and a survey.

When comparing the walking speeds collected in the current experiment with the walking speeds from previous experiments where people were asked to walk upwards long stairs, it can be seen that the walking speeds in the current experiment are higher. When comparing the vertical walking speeds, the result is reversed. A possible explanation for this is that climbing the stairs requires a larger vertical movement compared to moving in the tunnel where the movement is more horizontal.

In the current experiment, 59 % of the participants used an identifiable strategy when moving upwards in the tunnel. The strategies have been categorized as follows:

1) Adjust the walking speed to a pace the participant believe he/she can keep for a longer distance.

2) Focus on breathing.

3) Keep a lower walking speed in the beginning.

4) Concentrate on the surroundings to avoid thinking about how tired he/she is.

5) Focus on the goal.

In general, when walking up the tunnel the walking speed was more or less the same during the whole climb, but the participants experienced a considerable increased perceived exertion. This can be the result of Strategy 1 presented above.

The results of the current experiment show a tendency for walking speed to decrease with increased fatigue. A comparison between the rating of perceived exertion and the normalized walking speed indicates that the walking speed and fatigue stabilized during the movement in the tunnel.