Design of synchronous acquisition device for mine delayed seismic source

In mine seismic exploration, there is a certain time delay from the power-on to the explosion of the explosive source. This delay time directly affects the accuracy of mine seismic data processing and exploration results. In order to ensure the time accuracy of data acquisition in coal mines, a synchronous acquisition device for mine delayed seismic source is designed. When the detonator initiates, the high voltage current from the detonator produces an induced current through the current transformer. The induced current signal is converted into a voltage pulse signal that can be recognized by the nodal seismograph through the pulse shaping circuit. The near-field vibration pickup receives the vibration signal generated by the delayed detonation of the explosion and transmits it to the seismic acquisition substation. The seismic acquisition substation uses the vibration signal time and pulse signal time as the identification basis for the synchronous time of seismic data so as to obtain the accurate delay time of the seismic source explosion. Correcting the delay time of a single explosion in the data acquisition process can improve the synchronous accuracy of the seismic acquisition system. In terms of structure design, the design of passive circuit is obtained by adopting the core-structured current mutual inductance technology, so as to effectively solve the problem of connecting the leading wire with the synchronous acquisition device. The synchronous acquisition device is quickly installed and fixed on the anchor rod near the blast hole through the anchor rod connection hole. This method not only solves the problem of installing the synchronous acquisition device near the blast hole, but also receives the near-field seismic shock wave conveniently, quickly and accurately. The test results show that the synchronous acquisition device can be triggered within 10 μs, the trigger signal amplitude is about 2.5 V, the duration is about 30 ms, and the performance index meets the requirements of the synchronous acquisition device for seismic wave exploration.