矿井延时震源同步采集装置设计

Design of synchronous acquisition device for mine delayed seismic source

  • 摘要: 在矿井地震勘探工程中,炸药震源从通电到爆炸存在一定的时间延迟,这一延迟时间直接影响矿井地震资料处理及勘探成果的准确性。为保证煤矿井下数据采集时间精度,设计了矿井延时震源同步采集装置。当发爆器起爆时,发爆器起爆电雷管发出的高压电流通过电流互感器作用产生感应电流,通过整形电路将感应电流信号转换成矿用节点式地震仪能够识别的电压脉冲信号,同时近场震动拾震器接收炸药延时起爆产生的震动信号并传输给地震采集分站;地震采集分站以震动信号时间和脉冲信号时间作为地震数据同步时间的识别依据,从而获得震源爆炸的精确延迟时间;校正数据采集过程中单炮的延迟时间,可提高地震采集系统的同步精度。结构设计方面,采用穿心式电流互感技术实现了无源电路的设计,有效地解决了爆破母线与同步采集装置连接问题;通过锚杆连接孔将同步采集装置快速安装固定于炮孔附近的锚杆上,既解决了同步采集装置在炮孔附近就近安装的问题,又可方便、快捷、精准地接收近场地震冲击波。测试结果表明,同步采集装置可在10 μs内完成触发,触发信号幅度约为2.5 V,持续时间约为30 ms,性能指标达到了地震波勘探同步采集设备的要求。

     

    Abstract: 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.

     

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