التفاصيل البيبلوغرافية
| العنوان: |
脉冲雷达透地探测煤岩实验研究. |
| العنوان البديل: |
Experiments on ground-penetrating detecting coal-rock interface with radio pulse radar. |
| المؤلفون: |
张守祥1 zhangsx@sdtbu.edu.cn, 刘帅2 |
| المصدر: |
Journal of the China Coal Society / Mei Tan Xue Bao. Jan2019, Vol. 44 Issue 1, p340-348. 9p. |
| مصطلحات موضوعية: |
*GROUND penetrating radar, *ELECTROMAGNETIC wave propagation, *ULTRA-wideband radar, *COAL mining, *SEISMIC waves, *PULSE generators, *RADAR signal processing |
| الملخص (بالإنجليزية): |
Technologies such as transient electromagnetic, seismic wave, ultrasonic wave and ground penetrating radar, etc. have been utilized in the traditional coal and rock detection to transmit and receive signal frequencies below1 GHz. However, utilizing these technologies cannot give consideration to both the detection depth and accuracy. As the coal-rock interface shall reach the detection accuracy of 20 mm according to requirements of the automatic horizon control of shearer in the fully mechanized coal mining face, the high-precision depth detection technology that pene-trates the coal and rock seam with the radio pulse radar is proposed. Low-power and downsizing UWB(Ultra-Wide Band) radar is designed with mono-radar chip+RF circuit. And it’s the PG(Pulse Generator) that transmits a subnanosecond narrow pulsed electromagnetic waveform to output UWB signals at the center frequency ranging from 5.3 to8.8 GHz, the bandwidth ranging from 1.65 to 4.40 GHz and the power ranging from-17.2 to-10.5 dBm. Meanwhile, the input circuit collects the signal voltage of the peak-to-peak value ranging from 54 to 72 m V reflected from the coalrock medium. The UWB radar is arranged closely through the dual Vivaldi antenna being perpendicular to the coal and rock seam. The transmitting antenna sends 7 thorder Gaussian pulse UWB band signal as low as-19 d Bm, while the receiving antenna collects 512-depth return signals at a rate of 30 Gbps. In this way, the precise coal-rock interface location can be estimated through multiplying the propagation delay of pulse reflection and sending signals generated by the apparent difference of dielectric constant in the coal and rock by the electromagnetic wave propagation rate calculated after calibrating the dielectric constant of at the coal-rock site. Moreover, based on changes in the depth of coal seam and dielectric constant, the relationship of coal-rock detection among pulse vertical resolution, detection depth and length of the signal sampling window are established to determine that the length of sampling window is 256 ns with the measuring resolution reaching 4 mm. A waveform gray-scale map is drawn with pulse signal data collected for intuitively distinguishing the coal-rock interface location. To be specific, dark black and bright white in the map are the valley and peak of the signals, respectively, representing the interface locations of two media of coal-rock with great differences in the dielectric constant. In the meantime, the thickness of the coal seam is calculated by the time difference from the valley or the peak to the starting point. In the fully mechanized coal mining face and roadway field test for roof coal mining, the thickness of the coal seam measured with the error less than 20 mm can detect the thickness of the roof coal and the floor coal of the working face in the virgin coal, providing accurate location reference for the automatic horizon control of the shearer. [ABSTRACT FROM AUTHOR] |
| Abstract (Chinese): |
传统的煤岩探测采用瞬变电磁、地震波、超声波和探地雷达等技术,发射和接收1 GHz以下的信号频率,不能兼顾探测深度和探测精度。综采工作面采煤机自动调高要求煤岩分界达到20 mm的检测精度,为此提出采用无线脉冲雷达穿透煤岩层的高精度深度探测技术。设计成单雷达芯片+射频电路的低功耗小型化的超宽带雷达,由脉冲产生器PG(Pulse Generator)发射亚纳秒级的窄脉冲电磁波形,输出中心频率为5. 3～8. 8 GHz、频宽为1. 65～4. 40 GHz和功率为-17. 2～-10. 5 dBm的超宽带UWB(Ultra-Wide Band)信号,输入电路采集从煤岩介质反射回来的峰峰值达54～72 m V的信号电压。超宽带雷达通过双Vivaldi型天线垂直于煤岩层贴近布置,发射天线发出低至-19 dBm的7阶高斯脉冲超宽带波段信号,接收天线以30 Gbps的速率采集512级深度回波信号,利用煤岩存在明显介电常数差异所产生的脉冲反射与发射信号的传播时延,与现场煤岩介电常数标定后计算出的电磁波传播速率相乘,来推算出煤层厚度以精确地确定出煤岩分界位置。根据煤层深度和介电常数的变化建立了煤岩探测的脉冲垂直分辨率、探测深度与信号采样时窗长度关系,确定采样时窗长度为256 ns,测量分辨率达到4 mm。为了直观地分辨出煤岩分界位置,以采集的脉冲信号数据绘制波形灰度图,深黑色和亮白色分别表示信号的波谷和波峰,代表了介电常数有较大差异的煤岩两种介质的分界位置,并通过波谷或波峰到起点的时间差计算出煤层的厚度。在留顶煤开采的综采工作面和巷道现场测试,测量煤层厚度的误差小于20 mm,能够在煤层未开采前检测出工作面顶煤和底煤的厚度,为采煤机自动调高提供精准的位置参考。 [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
Academic Search Index |
