Numerical Studying of Explosion Effect on Buried Pipelines in Geosynthetics Reinforced Soil

In recent years by increasing the terrorist threats and explosive operations in urban areas, protecting the important life line infrastructures against threats that arise from the explosion has become more important. Hence, predicting the extent of the destructive power of the explosion and its effects on soil layers necessitates further studies and researches. In order to reduce stress caused by the explosion and to control increasing compressive and shear stresses in the soil and lateral pressure on the pipes, several solutions have been presented. One of these solutions is utilizing geosynthetic reinforcement. In reinforced soils, the mechanism of stress transfer is based on the interaction of soil and reinforcement elements. The shear stress reaction causes tensile forces in reinforcement elements. This phenomenon leads to an increment of shear strength, elasticity and ductility of the reinforced soil. In this study, FEM method is used for modeling pipelines buried in the reinforced sandy soil exposed to surface blast loading. By comparing the results, it can be concluded that by using reinforcement in the soil, the stresses and deformations in the buried pipeline could be reduced. The results show that the deformation rate obtained from the placement of reinforcements at a depth of 1.5 m from the ground level (with a fixed width), has decreased by an amount of 35%. In addition, the rate of reduction in deformation of the pipe crest has decreased about 51% using a 4 meter wide reinforcement at a constant depth of 1 meter.