Soil thermal treatment - Motorway Project

Thermal treatment of clayey soils

Client: Impregilo SpA
Industries: Transport and infrastructure
Services: Geotechnical Engineering, Drilling, In-situ testing
 

Assignment

Cohesive soils – fat clays being the most representatives of the group – put difficult geotechnical problems regarding the stability of soil masses. It is known that failure of natural or artificial slopes are indebted to the changes in the soil properties caused mainly by action of water, and very small variation of its content might be the cause of serious accidents.
 

Our Role

Geoservices did the conceptual design for a trial experiment associated with areas affected by landslides near the alignment of the motorway project.

Our role consisted of developing an experimental project in order to study the possibility of reducing the sensitiveness of clayey soils to the action of water. Thermal treatment of clayey soils proved to be an efficient method for this purpose. For very long time burning method was used for stabilizing and consolidating clayey soils, as applied in bricks manufacturing industry, by this mean considerations have been given to thermal treatment of earth with respect to geotechnical application.

This technique could be significantly used in stabilizing soil masses affected by instability phenomena, as a means for stopping slips and plastic flow in fat clays, or for reducing uneven settlement in soaked loess soils, or for stabilizing slipping areas affecting embankments.

Previous experiments were carried out in Romania for various applications. For this project diesel fuel was used within a group of vertical boreholes. The thermal treatment changed the mineralogic structure of clayey soils and volumes of non-sensitive stiff soil were created. Apart from that the soil mass in the neighboring borehole wall has been dried out. To improve this method described above experiments for optimization of fuel consumption and theoretical development of free draught heating process are still being undertaken.