Study on the Effect of Large Cross-Section Quasi-Rectangular Pipe Jacking near Side Crossing Viaduct Piles in Soft Soil Areas

Abstract

Due to its high section use rate and minimal environmental impact, pipe jacking technology is frequently utilized in the building of urban rail transit and other municipal projects. This paper develops a three-dimensional numerical model for the gradual construction of rectangular pipe jacking based on the quasi-rectangular pipe jacking metro station project on Shanghai Line 14 and examines the interaction between the subsequent construction of double line pipe jacking and pile foundation. To analyze the deformation pattern of the tunnel section and the ground surface during the construction period and to confirm the applicability and accuracy of the model, the simulation results are compared with the monitoring data. The findings demonstrate that although the bending moment of the pipe jacking section is distributed as a “butterfly” under the influence of the viaduct piles, the maximum positive and negative bending moments as well as the lateral and vertical radial deformations of the pipe section cross-section are all somewhat diminished. The ground surface settlement curve in the vicinity of the bearing platform exhibits a more pronounced non-uniform settlement when the two pipe jackings pass through the pile foundation in close proximity, one after the other. The largest horizontal displacement of the pile foundation is found inside the jacking pipe tunnel at a depth of roughly 17 m below ground, where pipe jacking II has a greater influence on the lateral displacement of the pile foundation than pipe jacking I. The study’s findings line up with the monitoring data, which can serve as a guide and aid in the development of initiatives of a similar nature.

A Segmented Calculation Method for Friction Force in Long-Distance Box Jacking Considering the Effect of Lubricant

“…The lubricant significantly influenced the controlling factors of the friction force; there was only one lubricate condition in the whole jacking length in previous numerical simulation studies [28][29][30], which does not reflect the changing lubrication condition in practical construction.…”

“…(2) Construction process: (i) Use the birth and death element method to excavate the soil, simulating the forward jacking of the box via displacement control [28][29][30]. (ii) Neglect axial offset and box deflection during jacking, assuming the box jacks forward in a straight line.…”