3D-FE Analysis of RC Tunnel with GFRP Shielding Under Internal Blast Loading

Due to high risk of terrorist attacks inside underground subway system, the blast resistant design has become very crucial. The present study deals with the non-linear analysis of underground RC tunnels with a layer of GFRP shielding subjected to internal blast of 10 kg TNT at the center point of tunnel using FE software ABAQUS/EXPLICIT [1]. The explosion inside tunnel has been modeled using CONWEP tool. The soil neighboring the RC tunnel has been modeled using Mohr–Coulomb plasticity model, concrete part of RC tunnel is modeled using CDP (Concrete Damaged Plasticity) model, reinforcement part is modeled using JC (Johnson Cook) model, while GFRP shielding is modeled using Hashin model. The performance of tunnel and soil is evaluated in terms of stress and displacement values at the crown of tunnel and the mid-point of top surface of soil. Two different soil conditions are also considered in order to check the effect of surrounding soil on the response of RC tunnel in case of explosion. The results obtained indicate that the use of GFRP shielding effectively reduces the displacement and stress values in soil and RC tunnel. Thus, it is concluded that this method can be utilized for blast resistant design of underground RC tunnels.