Evaluation of Soil-Pipe Interaction under Relative Axial Ground Movement

The expansion of urban communities around the world resulted in the installation of utility pipes near existing natural or artificial slopes. These pipes can experience significant increase in axial earth pressure as a result of possible slope movement in the pipeline direction. This research aims at utilizing the discrete-element method to investigate the response of a buried pipeline in granular material subjected to axial soil movement. To determine the input parameters needed for the discrete-element analysis, calibration is performed using triaxial and direct shear test data and the microscopic parameters are determined by matching the numerical and experimental results. The soil-pipe system is then modeled and the detailed behavior of the pipe and the surrounding soil as well as their interaction at the particle-scale level are presented. Conclusions are made regarding the suitability of the empirical approach used in practice to estimate the axial soil resistance in different soil conditions. This study suggests that caution should be exercised in calculating axial soil resistance to relative pipe movement in dense sand material. A suitable lateral earth pressure coefficient should be determined in these cases as a function of the soil and pipe properties. (C) 2017 American Society of Civil Engineers.