摘要
隐伏断层是影响工作面透明化建设、煤矿智能化发展的重要地质因素之一,槽波地震勘探是目前探测断层的常用方法。目前,槽波理论研究主要基于煤层弹性各向同性条件,但煤层是由有机物质和无机物质组成的层状沉积岩体,具有较强的黏弹性。基于Kelvin-Voigt黏弹性理论,采用三维交错网格高阶有限差分法,边界吸收采用PML吸收边界算法,研究了煤层黏弹性和断层断距对槽波传播的影响。结果表明:黏弹介质煤层中地震波能量衰减增强,高频部分能量衰减严重,黏弹介质更加接近实际煤层的衰减特性;槽波遇到断层后,z分量高阶Rayleigh槽波发生透射和绕射现象,产生了新的转换波组基阶与高阶Rayleigh槽波;煤层的横波品质因子Qs=50时,基阶槽波具有明显的频散曲线形状,Qs衰减至10时,高阶Rayleigh槽波仍有清晰记录,槽波能量峰值向低频移动;随着断层断距的增大,绕射和透射作用逐渐增强,转换波组能量逐渐增大,断层后z分量的转换波组能量逐渐增强,槽波能量峰值向高频移动。
Buried fault is one of the important geological factors affecting the construction of transparent working face and the intelligent development of coal mine. Channel wave seismic exploration is a common method to detect fault at present. At present,the channel wave theory research is mainly based on the elastic isotropic condition of coal seam, but coal seam is a layered sedimentary rock mass composed of organic and inorganic materials, which has strong viscoelasticity. Based on Kelvin Voigt viscoelastic theory, the effects of coal seam viscoelasticity and fault displacement on channel wave propagation are studied by using three-dimensional staggered-grid high-order finite difference method and PML(perfectly matched layer) absorption boundary algorithm. The following conclusions can be obtained. The energy attenuation of seismic wave in viscoelastic medium coal seam is enhanced, and the energy attenuation of high-frequency part is serious. Viscoelastic medium is closer to the attenuation characteristics of actual coal seam. After the channel wave meets the fault, the high-mode Rayleigh channel wave of z component transmits and diffracts, resulting in a new converted waves(fundamental-mode and high-mode Rayleigh channel waves). When the coal seam Q_(S)=50, the fundamental-mode channel wave has an obvious dispersion curve shape. When the coal seam Q_(S)decays to 10, the high-mode Rayleigh channel waves is still clearly recorded, and the energy peak of channel waves moves to low frequency. With the increase of fault displacement, diffraction and transmission are gradually enhanced, and the energy of converted wave group is gradually increased. After the fault, the converted wave group energy of z component gradually increases, the peak value of trough wave energy moves to high frequency.
作者
焦文杰
姬广忠
唐学武
刘振明
JIAO Wenjie;JI Guangzhong;TANG Xuewu;LIU Zhenming(School of Earth and Environment,Anhui University of Science and Technology,Huainan 232001,China;China Raiway Design Corporation,Tianjin 300251,China)
出处
《煤矿安全》
CAS
北大核心
2023年第1期154-160,共7页
Safety in Coal Mines
基金
国家自然科学基金面上资助项目(42074148)
安徽高校协同创新资助项目(GXXT-2019-029)。
关键词
黏弹煤层
交错网格高阶有限差分
槽波响应特征
断层
高阶Rayleigh槽波
viscoelastic coal seam
staggered grid high-order finite difference
channel wave response characteristic
fault
high-mode Rayleigh channel wave
