不同水平充填纵向采空区群的爆破动力响应衰减规律

以爆破荷载下不同水平充填的纵向采空区群动力响应为研究对象,考虑充填体与围岩的摩擦阻力作用,按充填采空区群的层数不同分为3种工况建立动力响应模型,分析各层中围岩、顶板和充填体的位移、速度响应衰减规律。计算结果表明:在爆炸应力波作用下,充填采空区群内各部位的振动具有一定滞后性;同一工况下,与位于同一层的围岩和顶板相比,充填体的振动频率衰减最快;各工况下,速度和位移的初始响应频率和幅值相近,但层数越多的充填采空区群的动力响应衰减速率越快,恢复至平衡状态所需时间也越短。将动力模型计算结果与数值模拟结果和现场监测数据进行对比,三者速度响应的幅值、频率接近,并具有相似的衰减规律,验证了动力响应模型的可靠性。

Pattern of blasting dynamic response attenuation of vertical goaf groups backfilled at different levels

In order to study the dynamic response of vertical goaf group backfilled at different levels under blasting load, three dynamic response models with different numbers of backfilled layer were constructed with the friction resistance between filling body and surrounding rock considered, and the attenuation patterns of displacement and velocity responses of surrounding rock, roof and filling body in each layer were analyzed. The results show that, subjected to blasting stress wave, the oscillation of every part of the backfilled goaf group exhibits time lag. In the same layer of a model, the vibration frequency of filling body attenuates faster than those of surrounding rock and roof. Comparison of the three models indicates that their initial response frequencies and amplitudes of displacement and velocity are similar, but the goaf group with more layers has higher response attenuation rate and spends less time to return to equilibrium state. Amplitude, frequency and attenuation pattern of velocity response calculated by the models are similar to the results from numerical simulation and on-site monitoring, which verifies the reliability of the dynamic response models.