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Considerations on the explosion resistant design of special infrastructures have increased in the recent

years. Amongst the various types of infrastructures, road and railway tunnels have a unique importance due to their

vital role in connection routes in emergency conditions. In this study, the explosion effects of a projectile impacting on

a railway tunnel located in a jointed rock medium has been simulated using 2D DEM code. Primarily, a GP2000

projectile has been considered as a usual projectile and its penetration depth plus its crater diameter were calculated

in rock mass. The blast pressure was, then, calculated via empirical formula and applied on the boundary of crater as

input load. Finally, the wave pressure propagation through the jointed rock medium was investigated. In part of the

study a sensitivity analysis has been carried out on jointed rock parameters such as joint orientation, dynamic modulus

and damping ratio. Their effects on tunnel lining axial force as well as bending moment have also been investigated.

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Investigation of projectiles penetration phenomenon has been carried out in non-cohesive soil (Sand) targets under dry, saturated and compacted conditions. Analytical studies have been performed on the linear and non-linear soil models to obtain penetration depth formulae for ogival nose projectile and the results are verified by experimental studies. In present work, three ogival nose projectiles each having weight of 1.0 kg and nose angle of 15o, 30o and 45o are dropped from a height of 10.0 m in rectangular tank filled up by non-cohesive soil target. The rigid projectiles made an impact on a uniform target material at normal incidence with striking velocity of 14 m/s and proceeded to penetrate at rigid-body velocity. The models require geometrical parameters of the projectile types, velocity and target shear strength for the overall penetration depth of projectile. In addition, some parametric studies have been also carried out for academic and field interest.