Gholam Reza Khanlari, Mohammad Maleki, Reza Hydari-Torkemani, Somaye Alipour, Fateme Naseri,
Volume 9, Issue 3 (12-2015)
Abstract
One of the best approaches to reduce transportation problem is to use the underground tunnels. Therefore, Niayesh highway tunnel was performed by the New Austrian Tunnelling Method (NATM) in the northern part of Tehran and it includes north and south tunnels. The excavation of tunnels and other underground structures cause considerable changes in local stress conditions around structures that lead to surface settlement. In this research, surface settlement has been studied for five sections (CS-1 to CS-5) by empirical methods, numerical analysis and actual settlements. For the empirical and numerical methods, O’Reilly and New (1982) method and also finite element method (PLAXIS2D software) have been used, respectively. On the basis of the obtained results, the numerical method in all sections (except section 3) is in agreement with the actual settlements. While, empirical methods have estimated the settlements more than actual values in those sections. Also, the achieved results from the aforementioned methods show that the maximum settlement due to tunnel excavation is more than allowable settlement and it is in risk condition
