Simulation for Ground Movements due to Pipe Bursting

Ground displacements are of primary concern when replacing pipelines in close proximity to existing buried utilities and structures. The objective of this research is to simulate the cavity expansion within the soil caused by the pipe-bursting process and to study the displacements of the soil in the vicinity of the burst pipe and at the ground surface with a finite difference plane strain model for an elastic-plastic medium. Soil parameters such as the bulk modulus, shear modulus, elastic modulus, Poisson’s ratio, dilation angle, and friction angle are varied in the simulations to study the effects of these parameters on the soil displacements due to pipe bursting. The results indicated that the soil movement was concentrated in a wedge-shaped zone between the centerline of the old pipe and the soil surface. In dense sand, the outward and upward effects dominate the displacement pattern in shallow pipe bursting, with considerable dilation occurring in the soil above the burst pipe. Close to the old pipe within the ground, the magnitude of ground movement is higher and decreases toward the ground surface. A higher bulk modulus and higher elastic modulus both lead to higher ground displacements. The simulation results are compared with the actual displacements measured in a field test.