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New shaft sinking technologies with low depth strata freezing
33A capacity are described. Costs, specification, installation and problems associated with drains installed through geosynthetic reinforcements are briefly considered. 891262 Soil improvement with granular piles Ranjan, G; Rao, B G Indian Geotech J VI7, N2. April 1987. P103-120 Systematic trials of granular piles to strengthen both cohesive and cohesionless soils are described. Single piles and pile groups, with and without skirts, were evaluated. A new concept of improving soils and checking for lateral displacement of the piles by introducing a rigid skirting of limited depth around a pile group is developed. Full scale tests determined limiting load capacities. A simple method of calculating settlement of plain and skirted pile groups is presented. Granular pile foundations show promise under offshore or dynamic loading conditions. 891263 Ground improvement by vibro dynamic compaction techniques Rahimi, M M; Bayetto, P M Proc International Symposium on Prediction and Performance in Geotechnical Engineering, Calgary, 17-19 June 1987 P183192. Publ Rotterdam: A A Balkema, 1987 Vibro dynamic compaction, an improvement on standard vibroflotation methods, has been successfully used to compact areas of heterogeneous fill. Stone columns are constructed by using a dropping hammer or driving a casing. The mechanism of VDC is explained and formulae to estimate the depth of influence presented. Settlement analysis based on elastic finite layer or finite element approaches is in good agreement with results of large scale plate load tests.
Ground freezing 891264 Construction of the Asfordby mine shafts through the Bunter sandstone by use of ground freezing Harvey, S J; Martin, C J Min Engr V148. N323. Aug 1988, P51-58 Exploration boreholes at Asfordby mine showed the presence of water bearing Bunter sandstones at 330m which would cause problems for shaft sinking. Subsurface freezing from an underground chamber above the waterbearing zone was chosen as a solution. The ground was frozen from 275-405m to prevent permeation of water under the ice wall and into the excavation. Freeze hole drilling, construction of the shaft and freeze chamber, ground freezing, shaft construction through the frozen ground, and thawing and abandonment are described. 891265 Ground freezing in full-scaled sublevel stoping at the Pyhasalmi Mine, Finland Rajalahti, M Proc 13th World Mining Congress, Improvement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 V2, P937-939. Publ Rotterdam: A A Balkema, 1987 Significant ore reserves remain in pillars between first stage sublevel stopes. The stopes are backfilled with non-homogeneous rock containing much fine material. The fill must be
stabilised to allow economic levels of pillar recovery. Stabilisation by cement or chemicals was unsuccessful,but the ground freezing technique proved suitable. Although expensive, it is technically successful, and economically justified in certain cases.
891266 Progressive measurement of icewall thiekne~ as a precondition for freeze shaft excavation Wollers, K Proc 13th World Mining Congress, Improvement of Mine Productivity and OeeraU Economyby Modern Technology, Stockholm, June 1987 V2. P953-957. Publ Rotterdam: A A Balkema, 1987 A method is described to continually monitor the thickness of the icewall by temperature and ultrasonic measurements, to allow shaft sinking to start as soon as thickness is sufficient to exclude possibility of water burst. A new technique is also described where the entire shaft volume is frozen, a pilot hole drilled, and the shaft formed by raise boring or by a rodless shaft boring machine.
891267 New shaft sinking technologies with low depths strata freezing Maloszewski, J; Napieracz, T; Rulka, K Proc 13th World Mining Congress, lml~ocement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 V2, P959-967. Publ Rotterdam: A A Balkema, 1987 Examples of the use of ground freezing in shaft sinking to great depths (760m) in Poland and Yugoslavia are presented. Where the entire depth of the shaft requires freezing, stage freezing is unsuitable as difficulties arise in maintaining lining continuity in the inter-stage depths. Wherever possible only selected strata are frozen, on economic grounds. Problems related to the great depths involved are considered.
891268 New development in sinking deep shafts by special methods in China Yongcheng, Z Proc 13th World Mining Congress, Improvement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 V2, P969-977. Publ Rotterdam: A A Balkema, 1987 Large areas of China's coalfields are covered by up to 700m of alluvium with complicated geohydrologlcal properties. A case study illustrates problems of sinking a freeze shaft in such regions. Correct selection of the thickness of the icewall in clays is examined. Heave of frozen soils, especially clays, can cause movement of the shaft lining or rupture of the freeze pipes. Preventative procedures are discussed, together with maintaining shaft verticality and shaft lining design.
Surface Structures See: 891246
© 1989 Pergamon Press pie. Reproduction not permitted
Ground freezing 891264 Construction of the Asfordby mine shafts through the Bunter sandstone by use of ground freezing Harvey, S J; Martin, C J Min Engr V148. N323. Aug 1988, P51-58 Exploration boreholes at Asfordby mine showed the presence of water bearing Bunter sandstones at 330m which would cause problems for shaft sinking. Subsurface freezing from an underground chamber above the waterbearing zone was chosen as a solution. The ground was frozen from 275-405m to prevent permeation of water under the ice wall and into the excavation. Freeze hole drilling, construction of the shaft and freeze chamber, ground freezing, shaft construction through the frozen ground, and thawing and abandonment are described. 891265 Ground freezing in full-scaled sublevel stoping at the Pyhasalmi Mine, Finland Rajalahti, M Proc 13th World Mining Congress, Improvement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 V2, P937-939. Publ Rotterdam: A A Balkema, 1987 Significant ore reserves remain in pillars between first stage sublevel stopes. The stopes are backfilled with non-homogeneous rock containing much fine material. The fill must be
stabilised to allow economic levels of pillar recovery. Stabilisation by cement or chemicals was unsuccessful,but the ground freezing technique proved suitable. Although expensive, it is technically successful, and economically justified in certain cases.
891266 Progressive measurement of icewall thiekne~ as a precondition for freeze shaft excavation Wollers, K Proc 13th World Mining Congress, Improvement of Mine Productivity and OeeraU Economyby Modern Technology, Stockholm, June 1987 V2. P953-957. Publ Rotterdam: A A Balkema, 1987 A method is described to continually monitor the thickness of the icewall by temperature and ultrasonic measurements, to allow shaft sinking to start as soon as thickness is sufficient to exclude possibility of water burst. A new technique is also described where the entire shaft volume is frozen, a pilot hole drilled, and the shaft formed by raise boring or by a rodless shaft boring machine.
891267 New shaft sinking technologies with low depths strata freezing Maloszewski, J; Napieracz, T; Rulka, K Proc 13th World Mining Congress, lml~ocement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 V2, P959-967. Publ Rotterdam: A A Balkema, 1987 Examples of the use of ground freezing in shaft sinking to great depths (760m) in Poland and Yugoslavia are presented. Where the entire depth of the shaft requires freezing, stage freezing is unsuitable as difficulties arise in maintaining lining continuity in the inter-stage depths. Wherever possible only selected strata are frozen, on economic grounds. Problems related to the great depths involved are considered.
891268 New development in sinking deep shafts by special methods in China Yongcheng, Z Proc 13th World Mining Congress, Improvement of Mine Productivity and Overall Economy by Modern Technology, Stockholm, June 1987 V2, P969-977. Publ Rotterdam: A A Balkema, 1987 Large areas of China's coalfields are covered by up to 700m of alluvium with complicated geohydrologlcal properties. A case study illustrates problems of sinking a freeze shaft in such regions. Correct selection of the thickness of the icewall in clays is examined. Heave of frozen soils, especially clays, can cause movement of the shaft lining or rupture of the freeze pipes. Preventative procedures are discussed, together with maintaining shaft verticality and shaft lining design.
Surface Structures See: 891246
© 1989 Pergamon Press pie. Reproduction not permitted