Mechanical simulation and calculation methodology of buried steel pipes under multiple loads

This study developed a 3D finite element model to study the mechanical behavior of buried steel pipes under multiple loads in terms of interlayer contacts among the soils, the pavement structures, and the buried steel pipes. Using this model, mechanical responses of the buried pipe under multiple loads are calculated to investigate the mechanical behavior in terms of soil pressure, stress, and deformation. Results indicate that: (a) the radial soil pressure, soil pressure coefficient, and pipe’s stress and deformation are positively related to the load level. However, the distribution of the three mechanical responses shows different patterns. The soil pressure at the top of the pipe increases more significantly than those at other positions. (b) When the modulus of foundation soil increases from 30 to 90 MPa, ΔX decreases by 19.02 %, and Mises stress σr4 decreases by 17.43 %, which indicates that good foundation treatment technology will reduce the soil pressure around the pipe; When the burial depth is increased from 0.6 m to 1.4 m, ΔX increases by 103.74 %, σr4 increased by 96.78 %, indicating that the optimization of design parameters of pipeline burial depth should be emphasized in the project. (c) The critical radial soil pressure on the pipe reaches 62.88 kPa under the B777 aircraft load, which is smaller than the soil pressure under the vehicle load during construction (90.21 kPa), indicating that the vehicle loads during construction should be further investigated in pipe design and construction. (d) The recommended values and ranges of the vertical and lateral soil pressure coefficient are provided; they are helpful for the design, construction, and management of the buried steel pipes.