Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Final report of the rock sealing project. Sealing of zones disturbed by blasting and stress release
Test 2 and 3 of the rock sealing project comprised determination of the hydraulic properties of the disturbed rock around tunnels and drifts and the possibilities of decreasing the hydraulic conductivity of the disturbed zones by an attempt to seal the very fine excavation-induced fractures that cause an increase in conductivity. This report deals with the grouting procedures and their effect while the hydraulic testing before grouting is described in volume 2. The macro flow test of the BMT drift before grouting showed that the disturbed zone around the drift has a highly increased hydraulic conductivity reaching more than 1 m into the rock from the periphery of the drift. The most conductive shallow part of this zone was grouted by 350 1 m long 'hedgehog' holes. The holes were injected with cement using dynamic as well as static techniques. The injections were preceded by laboratory investigations of the rheological properties of different cement mixtures, by theoretical modelling of grout penetration in factures, and by full scale injections in an artificial fracture. The macro flow test was repeated after the grouting and the results evaluated by using the same finite element models as before the grouting. The conclusion was that the effect of the grouting was very small. Excavation of the rock after grouting showed that the grout penetration has been very poor into chlorite-coated fractures and a conclusion was that such fractures are hardly groutable due to debris hindering the grout from penetrating. (au). (Atomindex citation 23:078618)
Final report of the rock sealing project. Sealing of zones disturbed by blasting and stress release
Test 2 and 3 of the rock sealing project comprised determination of the hydraulic properties of the disturbed rock around tunnels and drifts and the possibilities of decreasing the hydraulic conductivity of the disturbed zones by an attempt to seal the very fine excavation-induced fractures that cause an increase in conductivity. This report deals with the grouting procedures and their effect while the hydraulic testing before grouting is described in volume 2. The macro flow test of the BMT drift before grouting showed that the disturbed zone around the drift has a highly increased hydraulic conductivity reaching more than 1 m into the rock from the periphery of the drift. The most conductive shallow part of this zone was grouted by 350 1 m long 'hedgehog' holes. The holes were injected with cement using dynamic as well as static techniques. The injections were preceded by laboratory investigations of the rheological properties of different cement mixtures, by theoretical modelling of grout penetration in factures, and by full scale injections in an artificial fracture. The macro flow test was repeated after the grouting and the results evaluated by using the same finite element models as before the grouting. The conclusion was that the effect of the grouting was very small. Excavation of the rock after grouting showed that the grout penetration has been very poor into chlorite-coated fractures and a conclusion was that such fractures are hardly groutable due to debris hindering the grout from penetrating. (au). (Atomindex citation 23:078618)
Final report of the rock sealing project. Sealing of zones disturbed by blasting and stress release
L. Boergesson (Autor:in) / R. Pusch (Autor:in) / A. Fredriksson (Autor:in) / H. Hoekmark (Autor:in) / O. Karnland (Autor:in)
1992
156 pages
Report
Keine Angabe
Englisch
Radiation Pollution & Control , Radioactive Wastes & Radioactivity , Geology & Geophysics , Geologic Fractures , Radioactive Waste Disposal , Sealing Materials , Experimental Data , Grouting , Hydraulic Conductivity , Liquid Flow , Migration Length , Rheology , Rocks , Shaft Excavations , Stresses , Underground Disposal , Tables(data) , Foreign technology , EDB/540250 , EDB/052002 , Sweden