Silica sol for rock grouting: Laboratory testing of strength, fracture behaviour and hydraulic conductivity

被引:49
作者
Butron, Christian [1 ]
Axelsson, Magnus [1 ]
Gustafson, Gunnar [1 ]
机构
[1] Chalmers, Div GeoEngn, Dept Civil & Environm Engn, SE-41296 Gothenburg, Sweden
关键词
Silica sol; Grout; Grouting; Triaxial tests; Mechanical behaviour; Hydraulic conductivity;
D O I
10.1016/j.tust.2009.04.003
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
A recently introduced non-cementitious grout silica sol is a refined product of colloidal silica, where the particle sizes have been reduced to between 5 and 100 nm. Laboratory tests were performed to determine the behaviour of silica sol as a permeation grout in hard rock. The tests have involved methods Such as fall-cone, unconfined compression, triaxial, and oedometer tests. Samples were tested at different time intervals and in different storage environments. Results showed that the initial strength of silica sol, a few kPa, increases over time. Silica sol has a ductile behaviour during the first few days and then becomes elastic-plastic. Its hydraulic conductivity ranges from 10(-10) to 10(-11) m/s. When immersed in water, silica sol hardens and a thin layer of weaker strength is formed at the surface. However, this layer only extends a couple of millimetres into the sample; beyond that the silica sol is not affected, rendering breakdown by erosion a negligible risk. The conclusions are: (1) the strength obtained in silica sol after hardening is sufficient to withstand most grouting conditions; (2) when sufficiently confined, silica sol is able to withstand loading and unloading cycles: (3) a pH environment of around 11 does not appreciably change the strength of the silica sol; (4) silica sol is a material with low risk of failure under blasting vibrations: and (5) due to its low hydraulic conductivity, silica sol can be compared to low permeable clays. (c) 2009 Elsevier Ltd. All rights reserved.
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页码:603 / 607
页数:5
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