凍結融解による含水状態の溶結凝灰岩のクラック発生過程の関する研究

概要

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Freezing and thawing action as one of the important external factors of rock slope failures is emphasized in cold regions. Investigations were made on the crack development in saturated welded tuff specimen by freezing and thawing action in this study. The freezing test was conducted in a temperature-controlled chamber in the laboratory where temperature varied from +5 °C to-18 °C. The freezed rock specimens were thawed in distilled water. The test lasted 3.5 hours for each freezeing and thawing cycle including 2 hr for freezing and 1.5 hr for thawing. P-wave velocity and acoustic emission of specimens were measured during freezing. The investigation on change of appearance on outer surface and section of the specimen as well as pore water migration and crack development were done. The initial cracks in rock specimen by freezing-thawing action started from the weak of surface layer such as pumice, mudstone and the interface of gravel and volcanic glass, then propagated to inside of the specimen. The cause is that the degree of saturation in surface layer is higher than that of inside due to pore water migration during freezing. The patterns of cracks by freezing and thawing is affected by the rock structure and pore water migration.
社団法人資源・素材学会の論文
2000-01-25