Love型槽波三维地震物理模拟试验研究

3D seismic physical simulation experiment of Love in-seam waves

三维槽波地震物理模拟技术一直以来都是超声地震物理模拟的一个难题,国内外开展的相关工作较少。要成功模拟出Love型槽波,需要从槽波波场特征、模型设计浇筑、数据采集系统、固体采集耦合等方面系统考虑。针对三维槽波地震物理模拟成功的关键技术参数分析、发射接收系统关键器件-换能器的性能特征、不同直径换能器组合的激发接收方式、槽波物理模型设计制作以及固体模型数据采集等方面开展试验研究,成功模拟出了特征明显的Love型透射槽波。研究结果表明:①模型设计时煤层厚度不能大于30 mm,但必须大于换能器尺寸的2倍以上,且应与探头激发的波长相当,否则无法成功激发出明显的Love型槽波;②直径1 mm的点状换能器和直径8 mm的平面换能器,在无负载条件下,从能量传输效率、子波幅频特性等方面对比,平面换能器均优于点状换能器;③点状换能器和平面换能器不同组合方式作为激发、接收点,在铝板和有机玻璃板为负载的综合试验情况下,要在现有设备条件下实现三维槽波物理模拟只能采用平面换能器作为接收点,激发源可任意选择;④平面换能器激发接收的Love型槽波信噪比高、艾里相能量强,能清晰分辨模型中断层,而点状换能器激发接收的槽波记录信噪比、艾里相能量较弱,无法识别模型中的构造。

In the field of ultrasonic seismic physical simulation,the physical simulation technology of 3D in-seam wave seismic has rarely been carried out and there are limited related works reported.To successfully make the Love in-seam wave be simulated,the consideration of wave field characteristics of the in-seam wave,model design,data acquisition sys-tem,and solid acquisition coupling systematically is necessary.Therefore,the experimental researches were conducted on the key technological characteristics analysis of the 3D in-seam wave seismic physical simulation,and the performance characteristics of the key device of transmitting and receiving system called transducer.Also,the researches focused on the excitation and receiving methods of transducer groups with different diameters,the design and manufacture of the in-seam wave physical model and the data acquisition of the solid model.The Love transmission in-seam wave with obvious char-acteristics was successfully simulated.The results show that①when the model is designed,the thickness of the coal seam should not be greater than 30 mm,but must be greater than 2 times the size of the transducer and equivalent to the probe excitation wavelength,otherwise the obvious Love in-seam wave cannot be successfully excited.②The plane transducer with a diameter of 8 mm are superior to the point transducer with a diameter of 1 mm in terms of energy transmission effi-ciency,wavelet amplitude-frequency characteristics and other parameters without any load.③Different groups of point transducers and plane transducers are used as excitation and receiving points.When aluminum plate and organic glass plate are adopted as loads for synthetic testing,to achieve the physical simulation of the 3D in-seam wave,the plane trans-ducer can only be used as the receiving point,and the excitation source can be optional randomly.④The Love in-seam wave collected and excited by planar transducer has a high signal-to-noise ratio and strong airy phase energy,clearly dis-tinguishing the collapse columns and faults in the model.While the in-seam wave recorded and excited by point trans-ducer has a weak signal-to-noise ratio and airy phase energy,which cannot identify the structure in the model.