. . 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. 7the 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.