Elastic Wave Advanced Detection By Short Acquisition Array And Traveling Wave Separation

In the process of tunnel or roadway excavation, the potential geological hazards which might exist in front of the construction heading face would probably trigger various excavation risks when the situation is unclear. Further, it might bring negative influence to the construction schedule, and even a threat to the safety of lives and property. To solve this problem, both the domestic and overseas engineering communities have attached great importance to the application and development of the advanced detection technology. This paper presented a technology named ’Seismic Wave Advanced Detection with Short Acquisition Array’and further investigated it with the separation algorithm of the traveling wave in the wave field records.Various advanced geophysical detection technologies at this stage were comprehensively reviewed. Based on those, the advanced detection with short acquisition array was represented by taking the various detection problems into account, such as the complex geology and geophysics background in the roadway advanced detection, the limitation in the roadway construction space and the interpretation of the three-dimensional underground space. The advantages of this technology were summarized as follows:the array data collection method can takes full advantage of the apparent velocity reverse characteristics of up-going and down-going waves to provide favorable conditions for the extraction of reflected wave field; the acquisition system united with fine designed observation device can help to form a simple and effective set of advanced detection equipment and realize all-round and multi-angle exploration; this method can also improve the signal-to-noise ratio of the acquisition records by multiple stacks of hammer source instead of explosive source; the effective and consistent coupling conditions of multi-channel sensor protects the consistency of the multi-channel signal acquisition while reducing the interference to the desired signal; furthermore, the records from short acquisition array can possibly increase the spatial sampling rate of the seismic wave signal. In this paper, the records of advanced detection with short acquisition array were simulated by staggered finite-difference method. Then the Curvelet filtering algorithm was also selected for data de-noising. The F-K filtering and τ-p filtering methods were used for separating the traveling wave filed and comparing both the numerical simulation and physical testing records. Accordingly, on the basis of the advantages and disadvantages of these two methods, a two-dimensional unite-filtering method was proposed. Hence, the series of processing steps would effectively extract the reflected wave field records and improve the resolution ratio of the seismic wave data. This paper includes39pictures,1sheet and67references.