Temperature effects on engineering properties of loess: Application to a loess of the Parisian Basin from 5°c to 80°c

Abstract

Huret, C., Cojean, R. and Deveughéle, M., 1988. Temperature effects on engineering properties of loess: application to a loess of the Parisian Basin from 5°C to 80°C. Eng. Geol., 25: 209–228. We present here an experimental work about the engineering behaviour of a calcareous loess from the Parisian Basin, the Rungis loess, in a temperature range of 5°C and 80°C. Mechanical testings on a collapsed and remolded material were realized with a specific apparatus. It allows us to give a stress and temperature history to the material while the process remains simple. The temperature speeds up primary consolidation which is attained five times quicker at 80°C than at 20°C. The viscous flow of the skeleton and the compressibility are also increased in the same range. The consolidation phenomenon is theoretically analysed using both the classical Terzaghi approach and a rate process theory. The volume variations induced by a modification of the sample temperature is analysed and each phenomenon (thermic dilation, double layer modification, granular rearrangement) is emphasized. All along this work, we have evaluated the specific characteristics of the loess: granularity, geochemistry, physico—chemical forces and structure. We emphasized the study of the microstructure of the material using pore size distribution measures by mercury intrusion and scanning electron microscopy. This permits us to relate the mechanical behaviour of the material to its micro-structure and to the pysico—chemical properties of the particles.