TRACKING IN SITU MOISTURE TRANSIENTS IN HEATED CLAY

An in situ experiment was carried out to examine the thermal-hydraulic-mechanical interaction between an initially unsaturated sand-bentonite clay buffer, a heater and granitic host rock. Conventional thermocouple psychrometers and thermal needles were installed within the clay buffer to track moisture transients in the material. Based on observations during the heating phase of the experiment and on results conducted after the test, it is concluded that the data from the instruments did not precisely indicate the moisture contents in the clay. Elevated temperatures, temperature gradients, and thermally induced vapour pressure gradients affected the readings. However the data clearly indicated the patterns of moisture transfer in the clay under heating. (A) For the covering abstract see IRRD 881647.