基于数值模拟的顶板围岩损伤过程 动力响应信号的能量分析

 通过室内相似模型试验，模拟金属矿山巷道顶板从稳定状态到损伤发展直至顶板冒落的过程，利用封装应变传感器的光纤光栅锚杆监测振动信号，记录不同围压、不同冲击振动强度下裂隙顶板与完整顶板响应信号，利用小波变换提取信号的频带能量分布特征。根据室内试验对光纤光栅用于顶板稳定性监测的研究成果，利用径向基函数神经网络对监测时间序列进行预测，并基于频带能量的观点，利用Matlab建立不同损伤条件下的瞬态冲击信号评估系统，并对一段连续信号进行分析。损伤顶板振动响应信号的频带能量受到裂隙开展的影响，与完整顶板相比，出现明显的频带尖点，能量峰值从高频向低频移动。基于小波频带能量的围岩顶板稳定分析方法，首先，利用小波分解各频带能量分布特征，并通过分解结果中应力波的能量衰减程度可判别出岩体中是否存在裂隙；其次，利用小波分解后各频带能量比和归一化能量比来确定损伤程度和裂隙开展状态，为金属矿山巷道顶板稳定性监测提供了一种较为可靠的方法。

ENERGY ANALYSIS OF DYNAMIC RESPONSE SIGNALS DURING DAMAGE PROCESS OF ROOF SURROUNDING ROCK BASED ON NUMERICAL SIMULATION

The similarity model experiment is carried out to simulate the whole process of damage development of roof of metal mine laneway falling from stability. Fiber Bragg grating sensors installed in bolt are used to record the response signal of complete roof and damage roof under different confining pressures and different vibration intensities，and wavelet transform is utilized to extract vibration response signal of the band energy distribution characteristics. Finally，according to the result of the indoor experiment，the monitoring time series is predicted using radial basis function(RBF)；based on the view of energy band，the transient signal evaluation system under different damage conditions is established using software Matlab；and a serial of continuous signal are analyzed. The vibration response signal energy of damage roof is influenced by developed fracture. Compared with the complete roof，there is an obvious band cusp that the energy peak moves from high frequency to low frequency. Based on roof stability analysis method of wavelet frequency band energy，attenuation degree of wavelet decomposed frequency band energy is considered as the distinction that roof is stable or not. The frequency band energy ratio and the normalized energy ratio are used to determine the degree of damage and fracture state，which provides a reliable method for stability monitoring of laneway roof in metal mine.