Abstract：This paper introduces the design principle of the automatic observation instrument for frozen soil,and designs the field and laboratory test scheme for frozen soil.The test is based on the reference standard of TB1-1 frozen soil instrument,then comparative analysis has been made on the performance of five types frozen soil automatic instruments,and the causes of errors have also been analyzed.Through experiment,the systematic error between automatic and manual observation is ±2cm,when it is compared on external field test,and standard deviation and misjudgment depth is within 4cm.The frozen soil automatic instrument can reflect the freezing state of the soil at test site.The deviation between automatic and manual observation in laboratory testing is small,which has proved the feasibility of replacing artificial observation with automatic observation instrument.
2020, Vol. 37 
