Research On Three-dimensional Measurement Of Underground Deformation Based On Core-twitching Variable Inductance

Underground deformation monitoring plays an important role as an important means of geological hazard monitoring,and the geotechnical mass is bound to produce corresponding displacement when underground deformation occurs.Aiming at the problems of complicated operation,difficult installation and easy damage in the existing underground deformation monitoring technology,this paper puts forward a three-dimensional measurement technique of underground deformation based on core twitching variable inductance.The displacement and displacement direction of underground rock and soil are monitored,the following are specific work content:1.Analyze the advantages and limitations of existing underground deformation monitoring techniques,and use a variety of technical means to draw on the design of sensors.2.The sensor structure is designed by studying the technology of mutual inductance,Variable inductors,bridge circuits,tilt measurement and geomagnetic measurement.3.According to the sensor measurement requirements of the device selection,design and manufacture of sensor hardware circuit,and debug circuit functions.4.Build the experimental platform,write the sensor lower computer main program and the host computer software,to achieve the control of the experimental platform and experimental data acquisition and storage.5.The corresponding structure is designed and manufactured to install the inductance line in the sensor unit,and the relationship between the extraction length of the inner core of the inductor line and the measured voltage is calibrated by experiments.The measurement of tilt angle and tilt azimuth of sensor element is realized by using tilt measuring sensor and magnetometer.The displacement calibration experiment is designed and carried out to collect the transformer voltage data and the corresponding displacement data.6.By using the data obtained from the displacement Calibration experiment,the mathematical model is established,and the relative displacement value between the sensor units is measured experimentally and compared with the actual displacement value,and the overall error between the horizontal displacement and the vertical displacement measurement of the sensor is obtained between-3mm~+3mm,and the error in the measured value of horizontal displacement and vertical displacement in most positions is between-2mm~+ 2mm.The sensor designed by the author can be applied to a variety of geological environments,sensor units can be combined with geotechnical movement,while the measurement of vertical and horizontal displacement between sensor units can be achieved,three-dimensional measurement can be achieved,the underground deformation has a certain monitoring effect,compared with other underground deformation monitoring means can more fully reflect the displacement of underground rock and soil,It lays a foundation for the related research of subsequent underground displacement monitoring.