SHI Jiang-wei, FAN Yan-bo, PEI Wei-wei, et al. An investigation of deformation mechanisms of jointed pipelines due to underneath tunnel excavation[J]. 2021, 42(1): 143-150.
DOI:
SHI Jiang-wei, FAN Yan-bo, PEI Wei-wei, et al. An investigation of deformation mechanisms of jointed pipelines due to underneath tunnel excavation[J]. 2021, 42(1): 143-150.DOI: 10.16285/j.rsm.2020.0522.
An investigation of deformation mechanisms of jointed pipelines due to underneath tunnel excavation
The underground pipelines are connected by socket joints
and the continuity of the pipeline depends on joint rigidity. However
previous studies mainly simplified pipelines as continuous structures
and the effect of joint rotation on pipeline deformation mechanisms was ignored. By conducting centrifuge model tests and two-stage numerical parametric studies
tunneling-induced deformation mechanisms of pipelines with different joints stiffness are explored in this study. Because of the existence of flexible joints
overall flexural stiffness of jointed pipelines is much smaller than that of continuous ones. Moreover
tunneling-induced joint rotation results in jointed pipelines to have a better ability to deform with surrounding soils. Thus
tunneling-induced settlement in jointed pipelines is much larger than that of continuous pipelines. By simplifying jointed pipelines as continuous structures
tunneling-induced pipeline settlement is grossly underestimated. A linear relationship between the joint rotation angle and volume loss is observed. Based on parametric studies
a dimensionless group of relative pipeline-soil stiffness is established to differentiate relatively rigid and flexible pipelines. Calculation charts between the relative values of the length of pipe segment
pipe-soil stiffness and joint rotations are established for relatively rigid and flexible pipelines
respectively. Centrifuge test results are used to verify the proposed calculation charts. The proposed method can effectively predict the joint rotation angle due to tunnel excavation. Research finding from this study can be used in underground pipeline network reconstruction projects in urban cities.