Numerical Finite-Element Investigation of the Parameters Influencing the Behavior of Flexible Pipes for Culverts and Storm Sewers under Truck Load

摘要

The objectives of this study are to evaluate the parameters that affect the behavior of flexible pipes for culverts and storm sewers and to examine the strength-limit states of such pipes proposed by the AASHTO bridge-design specifications. The flexible pipes investigated in the study are high-density polyethylene (HDPE), PVC, and metal pipes. The pipe diameters considered are 914 mm (36 in.) and 1,219 mm (48 in.). A three-dimensional finite-element (FE) model has been developed to simulate the behavior of buried pipes under truck load. Results from field tests conducted by the authors for large-diameter pipes under 2D, 1D, and 0.5D burial depths, where D is the pipe diameter, were used to evaluate the accuracy of the numerical model. Extensive parametric studies were then carried out to examine the effect of burial depth, backfill soil quality, and compaction level on the buried pipes, and their results are reported in this paper. The effect of these parameters has been evaluated in terms of thrust values at the pipe shoulder and springline, vertical diameter changes, and longitudinal strains. Regression analysis was carried out based on the FE model predictions for the first load pass and on results from a research study available in literature to predict the behavior of buried pipes with multiple load passes. The parametric study has shown that the performance of buried pipes varies with the soil type, and the increase of compaction level and soil cover reduces the stresses on buried pipes. The numerical predictions indicate that the provisions of AASHTO bridge-design specifications for HDPE pipes need to be reassessed for very shallow burial depths.