Influence of Void Formation Beneath Buried Pipes on Mechanical Behavior Using Three-Dimensional Finite Element Method

Abstract

The formation of voids beneath buried PVC pipes can occur due to various factors, such as inconsistencies in the pipe bedding soil and groundwater erosion which may lead to pipe cracking. This study employs a three-dimensional finite element method to investigate the influence of void size on the mechanical behavior of the pipe, specifically in terms of vertical deflection and bending moment. Additionally, the effects of burial depth, backfill soil modulus, and pipe stiffness were examined. The results indicated that an increasing the size of void beneath the pipe significantly elevates both deflection and bending moment. However, increasing the burial depth effectively reduces these values, thereby enhancing pipe stability. Furthermore, decreasing the modulus of the backfill material and the pipe stiffness slightly increases deflection and bending moment.  These findings highlight the importance of proper bedding and backfill design in maintaining the long-term structural performance of buried PVC pipes.