This study deals with the development of a new drilling technique. The main goal is to prevent boreholes from collapsing. The idea is to create baked in place casings by applying heat on the borehole wall.
The chemistry of clay and its transformation during heating was studied. All the reactions that occur when clay is heated up to 1000°C were explained.
The thickness of clay hardened by the heating process and necessary to prevent collapse of the borehole subjected to the soil horizontal stress was calculated theoretically.
Experiments were conducted to determine the strength gain of the clay when heated. A relationship between the moisture content and the strength was developed for the Mississippi Delta clay and the Buckshot clay.
An experimental probe was developed to check if the idea was feasible. A study of heat transfer in soil was performed experimentally and lent to the strength gain distribution in the soil. A finite element simulation was run in order to compare the results that were obtained experimentally with the theory of heat transfer. A theoretical calculation of the required energy to strengthen the clay was made.
