爆炸与冲击中的非线性岩石力学问题(Ⅰ):一维块系岩体波动特性的试验研究

Nonlinear mechanical problems in rock explosion and shock. Part Ⅰ:Experimental research on properties of one-dimensional wave propagation in block rock masses

与岩体构造层次相关的摆型波现象正逐渐形成非线性岩石力学的重要研究方向,并在诱发地震、岩爆及其他地震动事件的研究中展现出了重要的应用前景。利用自行研制的块系岩体动态力学性能测试试验系统,进行一维块系岩体模型的波动特性试验研究,测得一维冲击条件下块体振动的的频谱、振幅、波速特征,获得了迥异于连续介质中波动特性的摆型波特征现象,试验结果表明:一维冲击作用下,在冲击振动通过块系构造岩体向前传播的过程中,发生了从高频振动向低频振动的转移;相邻岩块间发生位移相差很大、甚至位移符号相反的相互对应的摆动;随着冲击比例距离的增加,块系岩体各块体加速度、位移幅值按指数形式衰减;摆型波传播的速度远远小于连续介质中纵波的传播速度,主要取决于块体间的裂隙宽度以及块体的运动速度。

Problems of pendulum-type waves associated with the tectonic hierarchy of rock masses are becoming an important research aspect of nonlinear rock mechanics, and presenting potential applications in studies of earthquakes, rockbursts and other seismic events. Thus, a new dynamic test testing system was designed, and a series of experiments were performed by the method of physical modeling, to reveal the characteristics of pendulum-type waves propagating in block rock masses. The frequency, amplitude and wave velocity were measured, then typical properties of pendulum-type waves in block rock masses which are quite different from waves in continuous media are obtained. Experimental results show that- In the process of vibration propagating from one block to another, the waves tends to transfer from high-frequency to low-frequency; Under the action of external pulse, tile displacements of tile adjacent rock blocks are quite different or even in different motion directions, restllt in oscillations of rock blocks one another and contacts broken. The vibration and acceleration amplitudes of each block attenuates with distance exponential ly; Tile propagation velocity of pendultim-type wave is far less than P-wave, and it mainly depends on tile widths of fissures between the blocks and the vibrational velocity of the blocks.