Mechanical behavior of concrete pipes with erosion voids and the effectiveness evaluation of the polyurethane grouting

Abstract

Research on pipes ringed by erosion voids is mainly concerned with circumferential mechanical behavior but ignores longitudinal bending responses induced by the relative motion of the pipe joints at voids. There has been limited innovative experimental investigation into pipe behavior that assesses the effectiveness of polyurethane (PU) grouting in rehabilitating erosion voids. Mechanical behavior tests of concrete pipes of intact, with an erosion void at the invert, and PU grouted were performed using a self-developed large-scale disaster testing system, and the measured results were numerically verified. Results show that the peaks of the positive and negative longitudinal bending moments of the intact pipes and pipes with a void at the invert appear at SgL2 and SgR2, SgL3 and SgR3, respectively, and the positive longitudinal bending moment is about 1.6–3.0 times higher than the negative ones. Voids at the invert have a significant effect on the longitudinal bending moments of the pipe segments located on the adjacent sides of the void. The longitudinal bending moments of the pipes with different void widths decrease with the increase of void width at SgL1 and SgR1 and increase with the increase of void width at SgL2 and SgR2, SgL3 and SgR3. The longitudinal bending moments of the pipes with different void lengths increase with the increase of void length in the whole longitudinal length. The circumferential bending moments at the bell-and-spigot decrease as the void width and void length increase. The maximum increases in the vertical displacements and maximum shear displacements of the pipes with different void widths and void lengths are 63–150% and 150–221%, 225–325%, and 325–550%, respectively, compared with the intact pipes. The rehabilitation efficiencies of the longitudinal and circumferential bending moments and the vertical displacement ranged from 85–93% and 85–94%.