Fracturing mechanism and crack expansion rule of concrete impacted by high pressure water jet

To reveal the fracturing mechanism and crack expansion rule of concrete under high pressure water jet impact, this paper established the numerical model of high pressure water jet impacting meso concrete based on the coupling method of Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH), which was verified utilizing Digital Image Correlation (DIC) and Computed Tomography (CT) technologies. Results indicate that a crater is generated under the strong water hammer pressure of water jet, and due to the existence of aggregate, the repetitious superposition of stress waves causes the irregular shape of the crater. In the intense action zone of water jet, the crack at protruding part of aggregate firstly appears and then connects to the crater or the other protruding part of the adjacent aggregate, forming the connecting cracks between aggregate and aggregate. And when the crack tips meet aggregate at a large angle, the energy of concrete can be fully released to aggregate, causing the crack penetrating aggregate. In the weak action zone of water jet, the decreases of stresses in concrete induce that cracks prefer to propagate along aggregate. Besides, with the sustained impact of water jet, the crater gradually enlarges, and internal cracks propagate to the boundary of concrete to form flank cracks, finally, the concrete takes place the whole debacle with the expansions and fusions of the internal cracks and the flank cracks.