. . The comparison of the results from Case 1 and Case 2 clearly reveals that the surrounding buildings may have significant interference effects on the wind speed amplification performance in each tunnel. As can be seen in Fig. 7 the existence of neighboring buildings can better intensify the wind speeds in the two upper tunnels by an average factor of 1.26 for tunnel-3 and 1.10 for tunnel-4. However, the interference effects in the two lower tunnels are direction-dependent.