PIPELINE DEFORMATION AND GROUND SETTLEMENT DUE TO BOX JACKING IN CLOSE VICINITY

The deformation of existing pipelines and adjacent foundations induced by box jacking is a critical issue for urban infrastructure safety. This study presents a comprehensive investigation based on a box-jacking project in Hefei, China, where pipelines and bridge pile foundations are traversed in close proximity. Field monitoring revealed that the ground settlement increased with jacking length, and the maximum ground settlement is 4.3 mm. The deformation of pipelines varied by material and burial depth, with cast-iron pipes showing smaller displacements than concrete ones. A validated 3D finite-element model was developed using Plaxis 3D to simulate the construction process. Parametric analyses indicated that increasing grouting pressure and face support pressure can effectively reduce structural deformation, while excessive section shrinkage significantly increases ground settlement. Furthermore, a novel ground-settlement prediction model was established using Physics-Informed Neural Network (PINN), incorporating the Peck formula and soil mechanics laws. Compared with LSTM and CNN models, the PINN achieved superior accuracy. The proposed approach effectively fuses physical laws and field data, and it can offer a reference for ground-settlement prediction in data-limited scenarios.