Właściwości termiczne piaskowców krośnieńskich
Abstract
THERMAL PROPERTIES OF KROSNO SANDSTONES
Summary
The problem of relations between thermal parameters and physical and mechanical properties, structure, texture and mineral composition is analysed on the example of the Krosno sandstones. The analysts covered changes in values of these features resulting from changes in moisture, direction studied and course of discontinuities. In the vertical (stratigraphical) profile the thermal properties of the Krosno sandstones are determined by their age as well as texture, porosity, degree of saturation with water and in a some degree by mineral composition. An important discovery in the case of the Krosno sandstones is the that studies have shown differentiated direction of thermal anisotropy. Directions more suitable to expansion depend on texture of sandstone. In thick-bedded sandstones the expansion is greater in the direction normal to the bedding and in the thin-bedded sandstones - in direction parallel to the bedding. Sandstones of the Krosno Beds are characterized by thermal conductivity coefficient λ ranging from 0.42 to 2.12 kcal/°mh, heat proper c - 0.18 to 0.35 kcal/°kGG, coefficient of temperature compensation a - 0.89 to 2.75 • 10-3 m2/h and thermal expansion coefficient β - 0.4-9.2 • 10-50C-1. The coefficient of heat conductivity is the lowest for thick-bedded sandstones and the highest for the corrugated. Intermediate values were found for thin-bedded sandstones. A full water saturation of sandstones results in increase of their heat conductivity two or three times or even more in higher temperatures. A differentiated thermal expansion of the Krosno sandstones results in unequal stress state in the rock massif and, therefore, in formation of fractures and discontinuities.
Summary
The problem of relations between thermal parameters and physical and mechanical properties, structure, texture and mineral composition is analysed on the example of the Krosno sandstones. The analysts covered changes in values of these features resulting from changes in moisture, direction studied and course of discontinuities. In the vertical (stratigraphical) profile the thermal properties of the Krosno sandstones are determined by their age as well as texture, porosity, degree of saturation with water and in a some degree by mineral composition. An important discovery in the case of the Krosno sandstones is the that studies have shown differentiated direction of thermal anisotropy. Directions more suitable to expansion depend on texture of sandstone. In thick-bedded sandstones the expansion is greater in the direction normal to the bedding and in the thin-bedded sandstones - in direction parallel to the bedding. Sandstones of the Krosno Beds are characterized by thermal conductivity coefficient λ ranging from 0.42 to 2.12 kcal/°mh, heat proper c - 0.18 to 0.35 kcal/°kGG, coefficient of temperature compensation a - 0.89 to 2.75 • 10-3 m2/h and thermal expansion coefficient β - 0.4-9.2 • 10-50C-1. The coefficient of heat conductivity is the lowest for thick-bedded sandstones and the highest for the corrugated. Intermediate values were found for thin-bedded sandstones. A full water saturation of sandstones results in increase of their heat conductivity two or three times or even more in higher temperatures. A differentiated thermal expansion of the Krosno sandstones results in unequal stress state in the rock massif and, therefore, in formation of fractures and discontinuities.