Distributed measurement of underground rock and soil deformation is an important part of geological hazard monitoring.By using parallel helical transmission lines as sensors and combining frequency domain reflection(FDR)analysis,continuous distributed measurement of larger deformation quantities is enabled.It is known that the characteristic impedance of the parallel helical transmission line increases with the increase of tensile force.Through FDR,the measurement and location of the tensile point can be de-termined.The principle of FDR measurement of tensile deformation in parallel helical transmission lines is explained.In response to practical application issues of FDR in parallel helical transmission lines,the influence of sweep range,frequency,and number of sam-pling points on measurement results is analyzed through experimental data.Different incident signals under different circumstances are also measured,factors that may affect measurement results are identified and analyzed,and a better measurement scheme is selected.The proposed method is used to simulate the actual use of parallel helical transmission lines and obtain actual measurement data,which is analyzed for better understanding.
维普
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