TY - JOUR JF - jeg JO - VL - 7 IS - 2 PY - 2014 Y1 - 2014/3/01 TI - Face Stability Analysis of Tunnel (A case study: Karaj Subway Line 2 ) TT - تحلیل پایداری جبهه تونل (مطالعه موردی : خط 2 متروی کرج) N2 - Tunneling in complex geological and geotechnical conditions is often inevitable, especially in urban areas. The stability analysis and the assessment of ground surface settlement of a shield tunneling are of major importance in real shield tunneling projects. The objective of this research is to determine the collapse pressure of a shallow circular tunnel driven by a Tunnel Boring Machine (TBM) of the Earth Pressure Balance (EPB) type.  In this study, analytical methods and three-dimensional numerical modeling with ABAQUS software were implemented to examine the effect of face pressure on the behavior of the tunnel. The parameters were calculated using data from Karaj subway-line 2 as a case study. The analytical method used in this study is Leca-Dormiex which is based on limit analysis theory.  The method is based on a translational multiblock failure mechanism.  Also, elastic and Mohr-Coulomb constitutive model have been used for soil behavior. The results of analytical method and numerical modeling were then compared. Based on the obtained results, face pressure assessed from the analytical method of Leca-Dormiex (upper bound) is the minimum pressure that can be implemented on the face tunnel. It also indicates that with implementation of suggested pressure of analytical method, Karaj subway face tunnel is stable and consequently execution of pre-consolidation methods in this section of the tunnel does not seem to be necessary SP - 1787 EP - 1810 AU - Headarian, P AU - Fatemi Aghda, S. M. AU - Noorzad, ali AD - KW - face tunnel KW - upper bound KW - method numerical KW - method analytical KW - face displacement KW - Karaj subway-line2 KW - ABAQUS UR - http://jeg.khu.ac.ir/article-1-422-en.html ER -