Lateral force–displacement relationships for shallowly buried pipe reinforced by geocells

Abstract

Geocell reinforcements are proposed as a thrust countermeasure for shallowly buried pipeline bends and tees. The proposed method is easy to construct and has shorter construction time than the use of conventional concrete blocks since it does not require curing. Lateral loading tests were conducted on plates reproducing pipe bends or tees to verify their effectiveness while understanding deformation mechanisms. In addition to changing the plate width and geocell pocket size, additional experiments were conducted with different geocell reinforcement dimensions, geocell tensile stiffnesses and tensile properties of the seams. An equation for predicting the force–displacement relationship was developed as part of the proposed design method. The experimental results showed that the sides of the reinforced ground were not fully integrated when the width of the geocell reinforcement was large relative to the plate width. It was also found that the maximum force hardly decreased, although the displacement increased slightly due to the reduction of the tensile stiffness of the geocells and the tensile force at the geocell seams. Moreover, a hyperbolic approximation of the force–displacement relationship of the geocell reinforcement was developed and the calculated values agreed well with the experimental values.