Analysis and Prediction of Ground Surface Settlements due to Tunneling,Case Study: City of Tabriz Subway

Generally, the ground is compressed by natural stresses. Any disturbance such as tunneling, changes the stress distribution and causes some deformations. If such displacements exceed threshold values, they will sometimes develop important problems related to serviceability of the buildings on surface and subsurface structures. This paper includes comprehensive investigations and analysis using a finite element software named Plaxis. The objective of this paper is to study the relationship between deformations and ground surface settlements by means of parameters like soil density, elastic modulus, tunnel diameter and depth of tunnel axis. According to the results, it is observed that these parameters have significant effects. It also shows that to what extent these parameters affect the soil behavior. Also by estimating surface settlements of the second line of City of Tabriz subway in the location of BH-10 borehole, it can be concluded that ground surface settlements, to a large extent, are dependent on contraction, as a significant parameter.