| Seismic reflection wave method has great advantages in the long distances advanced geological prediction of mine tunnels. However, seismic records in the mine are interfered seriously due to the limitations of the complicated underground geological conditions, tunnel construction environment and excitation and receiving condition, which cause the seismic has complicated wave fields and low signal-to-noise ratio. It is very difficult to identify and separate the advanced detection effective wave of the conventional reflectors. Therefore, this is an effective supplement for the advanced detection of reflectors to carry out the study of the advanced detection method of surface wave and converted wave under the whole space tunnel condition.This dissertationstart from the influencesof mine geological condition and tunnel on seismic wave propagation. The comparative analysis of whole space elastic wave numerical simulation and the features of wave field is done among the homogeneous medium, roof and floor of coal seam, vacuum tunnel and tunnel excavation damage zone. The results show that the main energy of seismic waves is transmitted in the form of the tunnel surface wave because of the existence of mine tunnel and roadway excavation damage zone. On the other hand, their existence makes the reflective surface waves of tunnelling face and the front abnormity intertwined together, which is difficult to separate. Thus, it leads todo the advanced detection by utilizingtunnel surface wave with strong energy, slow decay and easy to identify.The theory of the advanced detection method by using the conversion of tunnel surface wave and shear wave in tunneling face is expounded in this dissertation. And the computational methods of surface wave advanced detection of two observation system, which is the continuous tracking(or continuous digging) observation system and TSP as the representative of the conventional observation system, are analyzed and compared.The processing flows of wave field separation, velocity analysis, time-depth conversionetc. of tunnel surface wave are described. And based on Visual C ++. Net platform, advanced detection processing software of tunnel surface wave is developed with takingτ-p filtering and stacking velocity analysis as the core.Based on the numerical simulation of excavation damage zone with different stimulation and receiving hole depths, it is obtained that excavation damage zone has strong absorptive effect on body waves, especially press waves. The simulation and receiving hole that crosses the loose circle of surronding rock can improve the SNR of body wave signal, while the conditions of simulation and receiving has a little effect on TSST waves. That’s because the collection of TSST waves requires low levels of simulation and receiving. Therefore, TSST waves have an advantage over body waves in the roadway with mechanical vibration source such as hammering.By analyzing thereflection amplitude-frequency characteristics of reflective medias with different velocities, the quantitative relationships between seismic attributes(such as instantaneous amplitude, instantaneous phase etc.) and reflectioninterface velocities. The reflective interface properties can be qualitatively evaluated by applying seismic attribute extraction technology.The physical tunnel model of advanced detection is established with a vertical interface. The ultrasonic transducer is used for the physical simulation of tunnel surface wave advanced detection. Meanwhile, the TSST wave advanced detection technology is applied in the detection of underground fault broken zone and collapse column, and analyze the influences of different receiving hole depth on seismic signals. Through comparing withthe borehole lithology and borehole’s recording results, this method is regarded as an effective method for advanced geological prediction. |
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