LABORATORY STUDY OF STONE HEAVE IN TILL EXPOSED TO FREEZING AND THAWING

Authors
Citation
P. Viklander, LABORATORY STUDY OF STONE HEAVE IN TILL EXPOSED TO FREEZING AND THAWING, Cold regions science and technology, 27(2), 1998, pp. 141-152
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary",Engineering,"Environmental Sciences
ISSN journal
0165-232X
Volume
27
Issue
2
Year of publication
1998
Pages
141 - 152
Database
ISI
SICI code
0165-232X(1998)27:2<141:LSOSHI>2.0.ZU;2-Q
Abstract
Cyclic freezing and thawing of soils affect the structure and might, u nder certain conditions, cause stones and particles to move and reloca te. The movement of stones will influence the soil structure and creat e weak and loose parts with increased permeability. This phenomenon ha s been known for a long time, but the knowledge regarding the magnitud e of stone heave and soil conditions necessary for heave to take place has been lacking. Therefore, laboratory tests were carried out. Fine- grained till (moraine) was compacted to different void ratios and then saturated in a rigid wall permeameter which was exposed to one-dimens ional freezing and thawing in a closed water system. The movements of an embedded stone were measured by an X-ray technique. Unfrozen sample s, as well as samples frozen and thawed, were X-rayed and the stone mo vements were quantified after 1, 2, 4, and 10 cycles of freezing and t hawing. The results show that stone movements (vertical and horizontal ) take place due to freeze/thaw. The void ratio (the ratio of the volu me of void space to the volume of solid substance in the sample) was f ound to be a key parameter for whether upward or downward stone moveme nts took place. The downward movement occurred when the soil had a hig h void ratio, and the upward when the void ratio was small. In the loo se soil, the stone first moved downwards and then, when the soil becam e denser due to freeze/thaw, it changed direction and heaved. In the l oose soil, significant movements in the horizontal direction as well a s rotation of the stone were also found. (C) 1998 Elsevier Science B.V . All rights reserved.