Investigation of about the effective parameters on the underground circular tunnel settlement using FEM and PLAXIS software

Tunnels are the famous underground structures . We can use the analytical ,experimental and numerical methods to analysis the tunnels . Numerircal methods such as FEM , FDM , … are reliability , fast and are the best , special for the complex boundary conditons . Finite element method (FEM)and PLAXIS software used to parametric research of the effective elements on the tunnel settlemet . Diameter of tunnel , Depth of tunnel ( the distancebetween the tunnel center to the ground surface ) , adjacent building loading and distance between the tunnel center to the building , water table ,earthquake loading were the effective parameters on the tunnel structural behavior for the both of adhesive and cohesionles soils . Settlement of the tunnel crest was investigated in this article . The results showed the increasing settlement with the tunnel diameter unless for the diameter 4 to 5meters and reducing the settlement with the tunnel depth unless for the tunnel depth 15 to 20 meters for the undrained adhesive soil and the 6 storiesbuilding equivalent surcharge . The results showed reducing settlement with the tunnel diameter up to 4 meters for diameter and then increasing rapidly for the higher diameter values , Also the settlement reducing with the tunnel depth until the depth 15 meters and then increasing with the tunnel depth for the higher values for the cohesionless soil and the 6 stories building equivalent surcharge too .The results showed the linear relationship between the crest settlement and the building surcharge . The results showed that the crest settlement increases with the distance ( between tunnel center and building center ) until about 50 meters and then constant . For two horizontaltunnel dugout , the settlement reduces up to 40 meters for the center to center distance and then increases , but this settlement relationship to the soil and tunnel properties.

کلیدواژه ها:

Underground structure ، Analytical ، Experimental ، Numerical ، Reliability ، Adhesive soil ، Cohesionless soil