Study on depth weakening of reinforced concrete piles cutting by abrasive waterjets under submerged conditions

Abstract

In order to improve the efficiency and safety of shield machine cutting reinforced concrete piles, abrasive waterjets (AWJs) assisted mechanical combined cutting technology is considered a feasible solution. However, the water-rich flooding environment will cause the cutting performance of AWJs to weaken, which brings great challenges to the application of this technology. In order to analyze the influence of submerged conditions on the cutting performance of AWJs, the cross-sectional morphology of reinforced concrete piles cut by AWJs is explored using indoor experiments, and the weakening law of pile foundation cutting depth is revealed. The results show that the submerged environment greatly weakens the cutting ability, and the average cutting depth is reduced by about 20.0%. Rebar materials are more difficult to remove due to their high strength and strong plastic toughness, which is the root reason of the difficulty in cutting off piles. As the cutting times increases, the cutting depth discount factor initially decreases rapidly before stabilizing. At 380 MPa, the cutting depth discount factor remains stable at 0.49, while at 280 MPa, it stabilizes at 0.62. The findings presented in this paper can provide guidance and suggestions on waterjet parameters for AWJs assisted shield machine pile breaking. HIGHLIGHTS The cross-sectional change rules of reinforced concrete pile foundation cut by abrasive waterjets is clarified. The depth weakening effect of pile foundations cut by abrasive waterjets under submerged conditions is revealed. The cutting depth discount factor for rebars is established.