STABILITY OF UNDERGROUND STRUCTURES AGAINST THE INSTANTANEOUS LOADING ON GROUND SURFACE

The importance of designing stable underground structures against the ground surface explosion and it′s instantaneous loading is known to the practicing engineers. Normally any important underground structures such as underground hydro-electric power complex should be studied for any unforeseen Instantaneous Ground Surface loading. For this reason, the action of ground surface explosion on rock masses is undertaken in this project. The reaction of discontinuous rock masses is studied for the waves produced due to ground surface explosion using UDEC software. UDEC is based on the distinct element method and is suitable for dynamic analyses of discontinuous rock masses. UDEC is made use of for dynamic loading, and also studying the mod of transmission and dissipation of stress waves throw rock masses, and also it′s effects on the stability of underground structures. The studies revealed that the effective discontinuities (with low stiffness parameters) are very effective on reduction of explosion effects on underground structures. Furthermore it has been deduced that, if the angle between the direction of stress waves path and discontinuities direction is about 30 degree, then it will be the most suitable condition for stress waves dissipation and reduction in the explosion damage effects