Study on damage mechanism of concrete under water jet combined with mechanical breaking

Traditional mechanical breaking technology has the disadvantages of serious equipment wear, large vibration, large dust, and low breaking accuracy. Water jet assisted traditional mechanical breaking technology can improve the breaking efficiency of traditional mechanical breaking technology, reduce equipment wear and pollution. However, due to the problems of fluid-solid coupling and nonlinear failure, the fracture characteristics and damage mechanism of concrete arenot clear, which hinders the development of this technology. In this paper, the experimental system of water jet combined with mechanical breaking concrete is built, and the numerical model of combined breaking is established by smoothed particle hydrodynamics(SPH) method. The cracking characteristics and damage mechanism of water jet combined with mechanical breaking concrete are deeply explored. The results show that compared with the mechanical breaking method, this method reduces the breaking pressure by about 16%, saves the cost and improves the breaking efficiency. The water jet slit has a guiding effect, so that the cracks generated by mechanical breaking concrete are concentrated between the two slits, to avoid secondary damage to the original concrete structure. The mechanism of water jet combined with the mechanical breaking of concrete can be divided into three stages: crater formation stage, crack derivation stage, and stage of cracking.