Abstract: In order to study the mechanism of high pressure water jetting on the coal, the damage mechanism of high pressure water jetting on the coal is investigated by using numerical simulation, which is based on coal using J-H-C damage constitutive model and water jet using Bridgman equation. Based on fluid-solid coupling penalty function, a mode of numerical algorithm, the various damage forms of the coal are gained under different jetting pressures of water. The numerical calculated values are in good agreement with experimental results. The numerical simulation results show that, different water pressures of jet flow cause different damage patterns in coal. The shape of damage caused by jetting in the coal is staged and the recombination action of compression stress wave and tensile stress wave is the main factor that results in coal damage. With penetration evolving, compression zone and tensile zone reduce that are formed by high water. There is the critical breakdown pressure of water on the coal that has different fracture strength.

Key words: water jet, numerical simulation, damage, constitutive model