Field monitoring of mechanical parameters of deep-buried jacketed-pipes in rock: Guanjingkou water control project

Abstract

To monitor the mechanical performance of a deep-buried rock-jacketed pipe within the scope of the Guanjingkou Water Control Project in Chongqing during construction, an extensive field experimental program was performed. The pipe–rock contact pressure, pipe deformation, and jacking load eccentricity were monitored. Regarding the pipe-rock contact pressure, the following conclusions can be drawn: (1) the magnitude was independent of the pipeline depth; (2) the maximum magnitudes were detected at the crown and decreased towards the invert due to the pipe buoyancy; (3) the magnitude was constant at the crown and sides for increasing jacking forces, whereas it increased or decreased at the invert with pipe-uplift or pipe-incrustation into the surrounding rock, respectively. With regard to the strain patterns measured on the pipe, the results demonstrated that magnitude of those was only significant for high jacking force magnitudes. The experimental approach followed and the results obtained were found to be useful for future projects because such results are rarely reported.