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

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 system, 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 characteristics was successfully simulated. The results show that ① when 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. ② The 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 efficiency, wavelet amplitude-frequency characteristics and other parameters without any load. ③ Different 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 transducer can only be used as the receiving point, and the excitation source can be optional randomly. ④ The Love in-seam wave collected and excited by planar transducer has a high signal-to-noise ratio and strong airy phase energy, clearly distinguishing the collapse columns and faults in the model. While the in-seam wave recorded and excited by point transducer has a weak signal-to-noise ratio and airy phase energy, which cannot identify the structure in the model.