Experimental study for drying-out of soil around underground power cables

Abstract EN

Six types of soil were investigated for studying the drying-out phenomenon and the thermal behaviour of the soil around high power cables.

Specific gravity, grain size distribution, permeability and compaction tests were carried out for six types of soil.

The measured pF-curves and the recorded distributions of temperature with both time and distance at the stated conditions are presented.

Also, the distributions of moisture with distance are given.

From the analysis of the temperature distributions with both time and distance; it was found that the temperatures of some soil points are rapidly increased.

From the analysis of the measured distributions of moisture with distance, it was also found that all soil points of rapidly increased temperature had approximately zero moisture content.

So, the discontinuity found at the measured temperature distributions curves indicated the separation between two zones with high respectively low thermal resistivities or with dry respectively moist soil.

Drying-out phenomenon started at 54°C in sand 2 and at 57°C in sands 1 and 3.

During heating processes, it was noticed that some types of sand lose their moisture content faster than other sand types.