Centrifuge modelling of heat migration in soils

Abstract

Modelling heat migration in soils is of great interest in various civil and electrical engineering projects. Researchers have developed several analytical and numerical models to model heat migration in soils and their validity has been demonstrated by conducting conventional laboratory or field experiments. Though laboratory tests are inexpensive, quick and easy to perform, they lack simulation of the prototype conditions in terms of in-situ stresses. To overcome this, field tests, which are relatively costly, time consuming and difficult to perform, are found to be of immense help. In order to overcome these limitations, a geotechnical centrifuge can be used for studying heat migration in the soil mass. To demonstrate the utility of a geotechnical centrifuge for such studies, standard grade sand compacted to different states has been chosen. Using a line heat source, a thermal probe, thermal gradient has been imposed and migration of heat in the soil mass has been studied by recording its temperature as a function of time and radial distance. The study highlights utility of a geotechnical centrifuge in modelling heat transfer in the soil mass.

In Situ Determination of Thermal Resistivity of Soil: Case Study of Olorunsogo Power Plant, Southwestern Nigeria

“…The measurements include establishments of ten pits of about 1.5 m below the ground and verification and preparation of the thermal sensor (calibration) using standard glycerol in order to check whether it was functioning properly [23][24][25]. The thermal sensor to be used was then selected (TR-1 was used).…”

A methodology for determining thermal properties of rocks

“…The thermal probe, which has been fabricated for determining thermal resistivity of various materials [20], is depicted in Fig. 1.…”

“…The temperature of the probe can be determined with the help of a Type-T thermocouple (Type-T, copper constant can), which is attached to its surface. For determining thermal properties of soils, and to check its proper functioning, calibration of the probe has been done using standard glycerol [16,17,20]. However, as the probe cannot be inserted in the rock sample without drilling a hole, determination of the impact of drilling on the rock sample including the effect of 'contact resistance', due to the formation of air gap between the probe and the hole, becomes mandatory.…”

Development of a heating and cooling system for centrifuge modelling of energy piles at HKUST

“…As a result, the time required to model a thermal process in the centrifuge was reduced by a factor of N 2 with respect to an equivalent field test. Krishnaiah and Singh (2004) recreated heat transfer processes in dry and saturated sand with a range of densities by the use of a small centrifuge and confirmed the time ratio of 1:N 2 between model and prototype scales. Furthermore, direct theoretical derivation related to diffusion processes (i.e.…”