动静加载下组合煤岩的应力波传播机制与能量耗散

运用改进的霍普金森压杆,在波动力学理论的基础上,研究动静载下煤岩结构的应力波传播机制与能量耗散,分析应力波幅值和静载对煤岩组合体中应力波的波形、透射系数、反射系数和能量耗散的影响规律。研究结果表明:应力波幅值和静载明显的影响组合煤岩中应力波的传播性质;并且煤岩组合结构初始处于弹性与塑性状态的透射、反射系数随动载的变化规律是不同的。动载能量耗散随应力波幅值的增大而增大,随着静载的增大呈现先增大后减小的趋势。同时注意到组合煤岩在静载在0.50~0.75动载耗散能量迅速降低,并且组合加载下煤岩结构的破坏失稳可分为两种形式,包括动载主导和动载诱发,分别以动载和静载为主要能量源。由静载对应力波传播机制和能量耗散的影响可知,埋深不同或距离采掘空间的远近不同,应力波传播机制和能量耗散是不同的。

Under static loading stress wave propagation mechanism and energy dissipation in compound coalrock

On the basis of the theory of wave mechanics，stress wave propagation mechanism and energy dissipation of compound coalrock under coupled dynamic and static loading were investigated by improved split Hopkinson pressure bar.The influence of stress wave amplification and static loadings on waveshape，transmission coefficient，reflection coefficient，and energy dissipation was analyzed.It is shown that wave amplification and static loadings apparently affects the stress wave transmission in compound coalrock.And the relationship of compound coalrock between dynamic loading and transmission，reflection coefficient is different initially in elastic and plastic state.Dynamic energy dissipation increases with stress amplitudes increasing，moreover at first increases and then decreases with static loading increasing.Meanwhile dynamic energy dissipation declined rapidly between 0.50 and 0.75 static loading.Under couple dynamic and static loading there are two destruction styles of compound coalrock including dynamic loading leading and dynamic loading inducing.At last，the preceding analysis shows that stress wave propagation mechanisms and energy dissipation varies with the depth or distance from the mining space.