应力波在煤层中传递和阻隔规律及其控制冲击地压研究

The disturbance of external stress will cause dynamic instability of the limit equilibrium state of the initial damage coal, the plenty of accumulative energy will release instantly, this is the basic reason of rock burst formation. Therefore, mastering and controlling the transfer and attenuation law of stress wave in the coal body that can effectively prevent the occurrence of rock burst. The project is based on the discriminant criterion of stability for the equilibrium state of deformed system to establish the energy functional model of coal, rock mass with initial damage parameters, time parameters and disturbance parameters, which can obtain the stability of the system and the criterion of rockburst. By means of theoretical analysis, experiment and simulation, the propagation law of stress wave in dense coal , pore and micro joint surface and fracture coal is obtained. And the attenuation law of wave propagation in various types of artificial defects. according to the rock burst criterion, the calculation of stress wave caused by the instability of the system of non stability. Weakening law artificial defects of rock burst occurrence can be drawn by comparative analysis; The observation and theoretical calculation of the stress wave propagation in two kinds of coal bodies with or without artificial defects are carried out in the field, and the stability of the two kinds of systems are compared and analyzed to measure the level of artificial defects of stress wave and the degree of control of rock burst, and then adjust the theory. So the theory can be used to guide formation of rock burst .

外界应力波的扰动会造成含初始损伤煤体发生极限平衡状态的动力失稳，引起大量积聚能量瞬间释放，这是形成冲击地压的根本原因之一。因此掌握应力波在煤体中的传递衰减规律并对其加以控制引导，可以有效控制冲击地压发生。本项目依据变形系统平衡状态稳定性判别准则，建立含初始损伤参数、时间参数和扰动参数的煤岩体能量泛函模型，得到系统稳定性以及冲击地压发生判据；采用理论分析、实验和相似模拟相结合的方法得到应力波在致密煤体、含孔隙和微节理面、裂隙煤体中传播衰减规律，以及在含各类型人造缺陷煤体中传波衰减规律；根据冲击地压判据，计算应力波引起系统失稳的非稳定度。对比分析，得出人造缺陷对冲击地压发生的弱化规律；在现场进行有无人造缺陷两种煤体应力波传递的观测和理论计算研究，对比分析两类系统稳定性，来衡量人造缺陷对应力波的引导程度和对冲击地压的控制程度，对理论进行调整。以此来对控制冲击地压发生进行理论指导。

以外界应力波扰动造成含初始损伤煤体发生极限平衡状态的动力失稳为背景，探索应力波在煤岩体中的传播衰减规律，通过构造缺陷衰减应力波的特征参量，进而达到控制应力波扰动诱发的冲击地压灾害。. 考虑煤岩体系统扰动应力波对其干扰，从理论上研究了扰动应力波对煤岩体发生失稳的影响并进行了案例分析。理论计算得到煤岩体扰动应力波的能量随时间和距离的增加呈递减趋势。依据冲击地压失稳机理、扰动波理论材料力学稳定性准则、弹性力学最小势能原理得出扰动应力波失稳准则与冲击地压能量判据，冲击地压能量判据满足相应的条件时，冲击地压才会发生，引入典型案例进行检验，根据计算实例检验所提出的能量判据对冲击地压的发生可以有效判定，再根据冲击地压的能量冲击波可以判定冲击地压发生的位置和时间，即能量最小值才是能量冲击波开始形成的时刻，并且可以确定形成的初始位置。. 从实验角度对应力波在完整砂岩和缺陷砂岩中的传播衰减规律进行了研究，随着预制裂隙角度增加，黄砂岩中纵波波速呈现“缓慢减小-平稳发展-急剧减小”三个发展阶段，衰减特性呈三次多项式关系。应力波幅值随着传播时间增加而逐渐减小，并且幅值和应力波传播时间呈指数型函数关系。随着角度增加，衰减系数逐渐增大，应力波幅值随时间的衰减程度增加。裂隙角度增加，裂隙前后幅值衰减显著，且裂隙角度越大衰减率越大。随着试件所含裂隙数量增加，纵波波速值不断减小，且减小速率先大后小，而后趋于稳定。多条平行裂隙前后幅值衰减率介于29.21%~64.78%之间，衰减量和衰减率均由两部分组成(即线性部分和非线性部分)，线性部分由材料本身的内部孔隙率、含水率、微裂隙数量、密度等物理性质决定；非线性部分(即对数增长部分)由预制裂隙的宽度、间距、填充物密度、弹性模量、含水率、裂隙数量等因素决定。研究结论对应力波诱发冲击地压的机理及其控制和阻隔规律提出了参考和建议。