Short-base-line differential laser strain measuring instrument

Abstract

The invention provides a short-base-line differential laser strain measuring instrument. The short-base-line differential laser strain measuring instrument comprises a single frequency laser interference sensor, a suspension system, a measurement base line rod, a base line fixing device, a measurement control and signal recording and processing system, a measurement calibration device and a measurement reflector limiting system, wherein the single frequency laser interference sensor fixed on a first base rock and a measurement reflector form an integral single frequency laser interferometer; the measurement reflector is connected with the head end of a measurement base line through the measurement reflector limiting system; the tail end of the measurement base line is provided with the measurement calibration device, and is fixed on a second base rock through the base line fixing device; the suspension system is mounted in the middle of the measurement base line; and the single frequency laser interference sensor and the measurement calibration device are connected with the measurement control and signal recording and processing system through a signal connecting wire. The short-base-line differential laser strain measuring instrument has high cost performance, and can be widely applied to transformation and construction of a precursor digital network.

Description

technical field [0001] The invention relates to a laser strain device, in particular to an optical path structure layout and a fixed installation structure of a laser interferometer used for geoscience observation. Background technique [0002] The telescopic measuring instrument is an instrument for precisely measuring the relative change of the distance between two points in the crustal rock mass. It has important applications in the fields of observing crustal strain and solid tides, as well as studying the process of earthquake breeding and obtaining earthquake precursors. [0003] Since the American seismologist H. Benioff developed the first valuable quartz extensometer in 1935, the United States, Britain, the former Soviet Union, Japan, Belgium, Germany and other countries have successively developed high-sensitivity extensometers. instrument. The sensitivity of the instrument is generally 10 -8 Above, solid tides can be clearly recorded. [0004] Research in this ...

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Problems solved by technology

[0008] The displacement sensor in the extensometer invented at present mainly adopts the eddy current displacement sensor, the differential transformer displacement sensor, or the capacitance displacement sensor, among which the best displacement resolution of the first two is about 1nm; while the capacitance displacement sensor has a better resolution , can reach 0.01nm, but the disadvantages are that the parasitic capacitance and distributed capacitance have a great influence on the sensitivity and measurement accuracy, the output is non-linear, the connection circuit is complicated, and it is affected by humidity and electromagnetic interference. It is not very suitable for the reliability of the extensometer. High stability requirements, long-term work and other practical occasions

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