Study On Key Technology Of Frequency Band Broadening Of Extensometer

In recent years,in the daily observations of earthquakes and solid tides,some abnormal tremor waves accompanied by strong earthquakes have been found,but SS-Y extensometers and other precursor instruments cannot observe these high-frequency information.Broadening the frequency band of the extensometer can provide data support for a new frequency band for earthquake precursor observation,which has important innovative and practical significance for the development of earthquake precursor observation technology and earthquake prediction.This paper focuses on the data requirements of high-frequency information for earthquake precursor observations,delves into the key issues that need to be resolved in the expansion of the band of the extensometer,and finally provides a solution for a new short-baseline extensometer.The new design broadens the observation frequency band of the instrument and solves the problems of poor anti-interference ability,calibration value error and poor self-checking ability of the SS-Y extensometer,which improves the anti-interference ability and long-term stability of the instrument,while provides a guarantee for the reliability of the data.The research goal of this paper is to extend the observation frequency band of the extensometer from DC to several tens of seconds to DC to 100 Hz,and to solve the problem of lack of high-frequency information for strain observation of the extensometer.In order to meet the needs of high-frequency observation,combined with a series of problems existing in the SS-Y extensometer,the structure and core sensors of the extensometer are redesigned in this paper.The baseline length of the instrument is only about one meter,the structure of the baseline hanging wire suspension is cancelled,the differential capacitance sensor is used for displacement measurement,and the overall sealing is carried out,which realizes the miniaturization and integration of the instrument.Through the laboratory test of the instrument,the frequency band is widened to DC-200 Hz,the linearity and lattice repeatability are less than 1%,and the range is better than1 × 10,which meets the design goals and observation requirements.In actual observation and testing,the instrument has a clear coseismic response to the earthquake,the solid tide observation data is good,the calculated resolution meets the design requirements and national seismic industry standards.This paper provides a new extensometer solution,which innovatively solves the problem of lack of high-frequency information of the cave precursor observation instrument,and realizes the miniaturization and integration of the instrument.