孔隙流体耦合效应对射流冲击应力分布的影响分析

运用全解耦流固耦合理论，建立了水射流冲击岩石介质流固耦合数值分析模型，给出了数值算法，计算分析了考虑和不考虑孔隙流体耦合效应对射流冲击岩石时应力分布的影响规律。结果表明，在射流冲击作用下，如不考虑孔隙流体耦合作用，最大拉应力位于冲击面，离冲击中心径向距离与喷距成正比，最大剪切应力位于岩石冲击中心下部约0.5倍喷嘴直径位置；如考虑孔隙流体耦合作用，最大拉应力位于岩石冲击中心下部约0.4倍喷嘴直径位置。数值分析结果可为水射流破岩机理研究中岩石破坏准则的选择提供依据。

Influences of the pore-fluid coupling effect on impact stress in rocks impacted by water jets

Based on the uncoupled fluid-structure interaction theory,a numerical model has been proposed to study the fracture mechanism of rocks under water jet impact. The jet flow characteristics and the stress distributions in the system are calculated with and without taking account of the pore-fluid coupling.The numerical results show if no pore-fluid coupling is considered,the maximum principal stress will be located at the impact surface and the radial distance from the impact center is directly proportional to the corresponding standoff distance,meanwhile the maximum shear stress occurs about half of the nozzle diameter downward the impact center.On the other hand,when water jets impinge on the saturated rocks in which fluid flows according to the Darcy's law,the maximum principal stress occurs about 0.4 time of the nozzle diameter downward the impact center. The results can provided some ideas in considering the rock damage criterion for rock failure mechanism study under water jet impact.