The Meansurement And Fitting Reconstructio Of Tunnel Section Convergence Degree Of Coal Mine

The convergence degree of tunnel is the most intuitive reflection of thesurrounding rock’s stress changes. According to the principle of ultrasonicranging, we measured the floor convergence and the displacement of both sides,which reflects the displacement of the tunnel surface, namely the tunnelconvergence.And then the data of tunnel convergence was fit. And the threedimensional model of tunnel was restructured. All these provide guarantee forsupport and safety in production.This article mainly includes two parts: the ultrasonic ranging system andthe wireless communication system. According to the environmental constraintsin the tunnel, we designed a converse-trapezoid scheme by using three ultrasonicprobes’ detecting in turn. In the scheme we have analyzed and have comparedthe traditional method of ultrasonic ranging at first. And then we selected thepeak method of detecting time, which can predict accurately the echo arrivaltime. The system has chosen the ultrasonic probes whose center frequency is40KHz, and has taken the PIC MCU as the main control chip in the design ofhardware. In the transmitting circuit, SP3232is used as the driver chip, and inthe receiving circuit, LM358is chosen as the receiving chip. The system has metthe requirement of ranging distance, small blind area and strong anti-interference. In addition, it also has the advantages of convenientinstallation and reliable operation.Having taken CC2530as the core processor, the wireless communicationsystem transmits data to the communication terminal by relay way of hand inhand. And the data arrives at the host computer through the optical fiber of the485mode at last. Then the staff reconstruct the three dimensional model of thetunnel by analyzing the data and using the wire frame modeling method.Finally, the experimental test results showed that the ranging accuracy ofthe system is ideal. In addition, the paper analyses each factor influencing thesystem and finds the method to reduction of deviation. The article has achievedthe design requirements.