Finite Element Assessment of Prefabricated Cable Ducts Under Soil Cover and Wheel Loading

To investigate the mechanical performance of prefabricated cable ducts under soil cover and vehicle wheel loads, refined numerical analysis models were established using ABAQUS finite element software (ABAQUS 6.14-4)for three different structural configurations: four-piece type, inverted four-piece type, and layered type. This study is purely based on finite element numerical simulations without experimental validation. By varying the soil cover thickness (0.5 m, 1.0 m, 2.0 m) and the position of the wheel load (offset distance of 0–1.5 m), the displacement distribution, stress development patterns, and damage characteristics of vulnerable parts for the three duct types were systematically analyzed. The results indicate that under soil cover loads, none of the three duct types experienced damage, and the mid-span displacement and tensile stress of the top slab exhibited an approximately linear growth relationship with the soil cover thickness. The layered duct demonstrated the best overall integrity, with a maximum tensile stress of only 0.098 MPa at a soil cover thickness of 2.0 m, which is approximately 5.8% of that of the four-piece duct. Under wheel loads, the four-piece duct experienced damage under an unoffset 105 kN wheel load, with a maximum steel reinforcement stress of 419.6 MPa, exceeding the yield strength. Due to its double-layer reinforcement in the top slab, the inverted four-piece duct exhibited a failure load increased to over 140 kN, with a maximum steel reinforcement stress of only 103.1 MPa, showing significantly improved ductility. Within the analyzed load cases, no stress indicator exceeded the adopted material thresholds, with a maximum tensile stress of only 0.15 MPa, demonstrating the optimal comprehensive performance. The offset of the wheel load significantly reduced the tensile stress in the top slab; when the offset distance increased from 0 to 1.5 m, the reduction in tensile stress of the four-piece duct top slab exceeded 80%. However, it increased the unevenness of stress distribution on both sides of the duct and altered the stress mode of the side walls. All the above findings are obtained from numerical simulations and can provide a theoretical reference for engineering design. The research findings can provide a theoretical basis for the engineering design and optimization of prefabricated cable ducts.