Abstract: Tunnels in the urban soft soil area are frequently undercrossing the municipal streets. This paper provides a case history of emergency response of the sudden mush rush in during the tunnel excavation underneath a street. The comprehensive mitigation measures were proposed based on the subsurface geotechnical and hydrological conditions. The emergency response and the mitigation method effectively reduced the impact of the tunnel excavation on the operation of the municipal streets.

Key words: Urban Tunnels, Mud Rush, Undercrossing Project, Engineering Geology, Subway