节理岩体爆破开挖过程的动态卸载松动机理研究

提出岩体爆破开挖过程中初始应力场的卸载是一动态过程的观点，并利用波动理论分析了岩块在初始应力场瞬态卸载条件下的运动过程。研究表明，瞬间卸载条件下，岩块除产生弹性回复位移外，还会发生水平向的刚体位移，导致岩体结构面被拉开，岩体产生水平向松动现象。岩体初始应力较高条件下。动态卸载引起的岩块水平刚体位移远大于弹性回复变形值。计算结果同时表明，岩体结构面的张开位移与初始应力的平方近似成正比。岩体初始应力场的动态卸载过程能较好解释节理岩体开挖过程的松动机理。

STUDY ON THE MECHANISM OF JOINTED ROCK MASS LOOSING INDUCED BY DYNAMIC UNLOADING OF INITIAL STRESS DURING ROCK BLASTING

The viewpoint that the process of the initial stress unloading in rock mass during blasting is a dynamic process is brought forward, and the theory of stress wave and propagation is employed to analyze the movement process of the rock block under the sudden unloading of the initial stress during rock excavation by blasting. The results show that, under the condition of sudden unloading of initial stress, a rigid body displacement could occur, besides an elastically reverting displacement, which will lead to the opening of the jointed rock faces and the loosing of the rock mass. If the initial stress is high enough, the induced horizontal displacement of rigid body will be much larger than the elastically reverting displacement. The calculated results also show that the opening displacement of the jointed rock face is approximately proportional to the square of the value of the initial stress. The process of the dynamic unloading of the initial stress can be, employed to explain the mechanism of the loosing of jointed rock mass during rock excavation by blasting.