Influence of Tunnel Excavation on Tower Foundation Settlement Constructed on Sandy Soil

Abstract

Tunnel excavation below or alongside towers will be affected on stability and performance of towers because of soil movement and stress distribution changes around and below towers. A finite element model using program Plaxis 3d is carried out to investigate the settlement that occurs in the tower foundation as a result of advancement of tunnel in sandy soil. Mohr-Coulomb model is used to idealize sandy soil while linear elastic model used for idealizing concrete in tunnel lining and tower foundation. Many parameters have been investigated such as influence of vertical and horizontal distance from tower foundation and tunnel location on stability of tower during tunnel excavation. The results showed that the direction of wind load is affected by tunnel excavation direction, if the direction is the same direction tunneling and wind load leads to higher foundation tower differential settlement than in transverse direction. The location of tunnel in lateral direction (x) must be at least 2.5D from the centerline of the tower foundation and in vertical direction (y) must be at least 3D from base level of tower foundation to ensure stability of tower frame.