基于Fluent-EDEM流固耦合算法的水下台阶爆破爆堆形成过程研究

Study on Formation Process of Underwater Bench Blasting Pile based on Fluid-structure Coupling Algorithm of Fluent-EDEM

针对水下岩石台阶爆破过程中破碎块体复杂的受力运动及其堆积过程,采用FLUENT-EDEM流固耦合的数值计算方法,在颗粒间引入平行键与Hertz-Mindlin接触模型,通过巴西劈裂实验与数值计算的结果对比,标定了平行键的参数,并建立了水下台阶爆破模型,分析了水对岩体破碎和运动的力学作用机理,研究了水下台阶块体颗粒鼓包抛掷的整个运动过程,讨论了块体速度、块体分层堆积和流场特点。结果表明:块体颗粒堆积分层与其初始速度以及位置高度有关,台阶中部块体颗粒相对位置较高,在爆炸荷载作用下水平运动距离最远,上部堵塞部分的块体颗粒受爆炸荷载作用小,其主要在重力与浮力作用下翻滚覆盖在中部块体颗粒层之上。起爆初期爆炸能量主要是破碎岩石,水体无明显流速,随着块体颗粒的鼓包抛掷运动,台阶前表面附近的流体流线速度最大,当块体颗粒开始滚动滑落时,流线则主要受到颗粒的运动形式影响。另外,FLUENT-EDEM流固耦合的数值计算模型能精确模拟水下台阶爆破块体运动问题,可为水下岩体爆破工程提供新的研究手段。

To study the complex mechanical movement and accumulation process of broken blocks in the process of underwater rock bench blasting,a fluid-solid coupling numerical calculation method based on FLUENT-EDEM was adopted.Firstly,the parallel bond and Hertz-Mindlin contact model were introduced between the particles,and the parameters of the parallel bond were calibrated by comparing the results of Brazilian splitting experiment and numerical calculation.Furthermore,the underwater bench blasting model was established,and the mechanical action mechanism of water on rock mass breaking and movement was analyzed.Finally,the whole ejection process of particles from a submerged step block was studied,and characteristics of the block velocity,block stacking and flow field were discussed.The results show that the accumulation and stratification of block particles are related to their initial velocity and height,and the horizontal movement distance of the block particles in the middle step is the biggest under the explosion load action.Meanwhile,the block particles in the upper blocking part mainly roll and cover the middle block particle layer under the action of gravity and buoyancy,which are less affected by the explosion load.Additionally,the explosion energy is mainly used to break the rock at the initial detonation stage,and the water has no obvious flow velocity.With the bulging and throwing movement of block particles,the fluid streamline velocity near the front surface of the bench is largest.When the block particles start to roll and slide,the streamline is mainly affected by the movement form of the particles.Therefore,the fluid-solid coupling model by Fluent-EDEM can accurately simulate the block motion in the underwater bench blasting,which can provide a new research method for underwater rock blasting engineering.