DefinePK

Abstract

In the twin tunnel, the spacing between tunnels or pillar width is an important issue for stability, because the mutual interference between tunnels depends on it during the construction sequence. It must be calculated with respect to tunnel size, soil condition, foundation type, construction method, and construction sequences. The tunnel and soil around it responses are also dependent on the clear distance between tunnels. Therefore, enough clear distance between tunnels must be maintained to ensure the tunnel stability. Sometimes, the surface movements and the interaction with existing foundations are required to be calculated. The shallow and deep twin tunnels in the present research are analyzed using PLAXIS finite element software. The analysis results obtained from finite elements are compared with experimental test results and analytical solutions obtained by other researchers. The present study show that the interaction between twin tunnels can be ignored for tunnel distances greater than the diameter of tunnel multiplied by 4.