Research On The Key Technology Of A Short-baseline Water Tube Tiltmeter Based On Differential Capacitive Sensor

Earthquakes are one of the most harmful natural disasters in the world,and China is a country with a high frequency of earthquakes.Therefore,it is very necessary to forecast and predict earthquakes.The water tube tiltmeter is an instrument used to measure the change of crustal inclination and capture the information of earthquake precursors.It plays a very important role in earthquake prediction and prediction,and its observation data is an important support for earthquake prediction and prediction.With the rapid development of modern technology and the diversification of observation requirements,the problems of the DSQ type water tube tiltmeter cannot respond to short-period crustal deformation within 70 s,and the working medium is easy to evaporate and needs to be replenished frequently.In order to improve the function and performance of the water tube tiltmeter,this paper studies the key technology of the short-baseline water tube tiltmeter based on fluorine oil medium and differential capacitive sensor.The main work contents are:(1)The importance of widening the observation frequency band of water tube tiltmeters is analyzed,and the development process and optimization methods of traditional water tube tiltmeters at home and abroad are summarized.The key technologies that need to be studied for short-baseline water tube tiltmeters are summarized,and the innovations of the paper are summarized.(2)The working principle of the DSQ type water tube tiltmeter is analyzed,and the basis for selecting the working medium of the instrument is determined.Several working media that are not easy to evaporate were analyzed,and the basic physical properties were compared with the original distilled water working media.Finally,fluorine oil was determined as the working media of the short-baseline water tube tiltmeter.(3)Starting from the structural characteristics of the DSQ type water tube tiltmeter,the mechanical structure design of the instrument is completed based on the requirements of reducing the baseline length of the instrument,the ratio of the diameter of the bowl to the water tube,reducing the inherent period of the instrument,and broadening the observation frequency band of the instrument.The commonly used displacement sensors are analyzed and compared,and the displacement sensor suitable for the short-baseline water tube tiltmeter is selected;the displacement sensor and its signal conditioning circuit are designed,and the simulation experiment of the signal conditioning circuit is carried out by using the Multisim 14.0 simulation software,and it is concluded that the voltage and displacement are approximately linear relationship,linearity is 0.298%.(4)A short-baseline water tube tiltmeter experimental device was built,and the performance and electrical fast transient burst immunity tests were carried out on the experimental device.The test results show that the sensitivity of the short-baseline water tube tiltmeter experimental device is 20 m V/?m,and the linearity is 0.68%;When the voltage peak of the power port is 4k V,the pulse repetition frequency is100 k Hz,the circuit board is resistant Good interference effect.