Hi allor, I saw your answer to the question "Flac Simulation Tunnel lining" dated on 09-15-2009. My tunnel section is about square (11ftx13 ft) and overburden is 10 ft. It is underneath a 12" concrete building foundation. I used flac 2D to model the tunnel and get the design loading for the steel rib set and the reinforced concrete tunnel structure. I have questions about how to control the intermediate settlement after installing the steel rib set. What is the criteria, such as 1 inch set ... ...