DIFFERENT BEHAVIOUR OF CIRCULAR AND RECTANGULAR TUNNELS UNDER THE IMPACT OF EARTHQUAKES: A CASE STUDY FROM THE TUNNEL OF HANOI METRO SYSTEM

Abstract

Currently, the metro system is built in Hanoi, the capital of Vietnam. Hanoi's metro system was
designed to be shallow that of near-surface (with an average depth of ground is H = 20 m). Hanoi is located in
the Northern part of Vietnam, where it can be influenced by the highest magnitude of earthquakes is up to Mw
= 6.5 Richter, so the study of the effects of earthquakes to the tunnel's stability in the Hanoi metro system is
necessary. The paper studied and calculated for two cases of the tunnel’s cross-section of the Hanoi metro
system is circular and rectangular under effects of the earthquake, this has been the strongest earthquake may
have the impact to Hanoi. Based on the results obtained, the paper has given comments on the effects of
earthquakes to tunnel’s stability in studies of two case and given suggests about the cross-section shape of the
tunnel in Hanoi metro system that may be used to under the effect of the earthquakes.