黏弹性VTI煤层介质超声波传播模型建立与分析

煤岩界面自动识别是深部煤层无人采掘装备自主控制中的关键技术。利用煤和岩声阻抗的差异性，采用超声波检测煤层厚度达到识别煤岩界面的目的。以Kelvin-Voigt黏弹性模型及各向异性理论为基础，推导适用于具有垂直对称轴的横向各向同性(VTI)黏弹性煤层介质的二维一阶速度-应力波动方程，建立黏弹性VTI煤层介质数学模型，采用交错网格有限差分法模拟超声波场在煤层中的传播，并通过实验验证所建立的黏弹性VTI煤层介质模型和交错网格有限差分法的正确性。研究结果表明：黏弹性VTI介质数学模型和交错网格有限差分法适用于数值模拟超声波在煤层中的传播，为超声波煤层厚度检测和煤岩界面识别研究提供了理论基础。

Modeling and analyzing the propagation of ultrasonic waves in viscoelastic VTI medium of coal seam

The coal-rock interface recognition is a key technology of autonomous control of unmanned mining equipment in deep dangerous coal seam.The method of coal-rock interface recognition using ultrasonic waves was proposedbased on the differences in acoustic impedance between coal and rock.The medium model of coal seam was established by generalizing the first-order wave equation to Kelvin-Voight viscoelastic model and anisotropic medium.With the staggered-gird finite difference method,the propagation of ultrasonic waveswas simulated in the model.The medium model of coal seam was verified by experimental and simulation results.The research shows that the viscoelastic VTI medium modeland the staggered-grid finite difference method can be used to numerically simulate the propagation of ultrasonic waves in coal seam.Thus,it provides a theoretical basis for the coal-rock interface recognition using ultrasonic waves.