Instrumental complex for measuring the depth of soil freezing

The electronic freezemeter has been developed for studying of influence of the frozen soil layer thickness on a seismic signal. While the effect of soil temperature on the speed of seismic waves is investigated quite fully, the wave attenuation is only subject for investigation. The electrical properties of frozen soils have also yet to be satisfactorily measured. This instrument allows to carry out monitoring of an average condition of territories or to reveal local features of the area. The measurements are carried out in an automatic mode, without disturbing the natural context of environmental. The various applications to which these instruments can be put makes them indispensable tools for work on weak, loose, swampy ground, for determination of possible loading in road maintenance, low-depth engineering networks, pipelines, etc. For the purposes of initial testing, two prototypes of the device were designed. The pilot registrations were conducted in the autumn-spring period of 2016 and 2017 in the territory of the Moscow region. The obtained results show that both the absolute thickness of the frozen soil layer and the dynamics of the freezing depth depend very much on the conditions of the thermal sensor location (soil type, moisture and density, thickness of the snow and vegetation cover, illumination and purging). Tests of these prototypes fully confirmed the efficiency of the proposed method of recording the value of the soil freezing thickness.