Author/Authors :
Bolghonabai، Roohallah نويسنده The Alborz Tunnel site, General Mechanic Contracting Co., Alborz, Iran Bolghonabai, Roohallah , Farouq Hossaini، Mohammad نويسنده School of Mining, College of Engineering, University of Tehran Farouq Hossaini, Mohammad , Mohammadi، Mohammad نويسنده The Alborz Tunnel site, General Mechanic Contracting Co., Alborz, Iran Mohammadi, Mohammad , Nazem، Ali نويسنده School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran Nazem, Ali
Abstract :
Among various practical measures used for restriction of the ground surface settlement in such tunnels
driven in soft ground, selection of an appropriate excavation method plays a significant role. In this
paper, employing suggested diagram by Yu & Chern, corresponding values of Niayesh tunnel has
been inserted into the diagram. Later, two excavation methods namely: central diaphragm and side
drift methods have been suggested and numerically modeled using Finite Difference Method. Side
drift excavation pattern has finally been selected since it causes less settlement. To reach an optimized
selection of excavation sequence through side drift method, seven excavation patterns have thus been
recommended and numerically modeled. Results have revealed that the first pattern causes the least
amount of settlement. Consequently, the aforementioned excavation pattern has finally been
considered as an appropriate excavation pattern encompassing optimum excavation sequence for
Niayesh tunnel.
