Johan Claesson | Lund University (original) (raw)
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Papers by Johan Claesson
Grundlaggning med "platta pa mark" eller riktigare "bjalklag pa jord" kan ske... more Grundlaggning med "platta pa mark" eller riktigare "bjalklag pa jord" kan ske med kantforstyvad platta eller med platta och grundmurar. Enligt Svensk Byggnorm 67 ar grundlaggningsdjupet enligt huvudregeln 0,25 m. Grundlaggningsdjup maste emellertid knytas till ett stort antal forutsattningar. Genom tillgang till datorberakningsmetoder och stora datorer har det blivit mojligt att noga teoretiskt studera temperaturer och frostnedtrangning. I rapporten granskas olika faktorers inverkan pa frostnedtrangningen. Intill en byggnad ges mojlighet till en mera nyanserad bedomning av frostnedtrangning och grundlaggningsdjup. Ett forslag till andring av Svensk Byggnorm ges ocksa. Genom ett stort antal diagram, baserade pa datorberakningar, ges lasaren mojlighet till bedomning av egna okonventionella konstruktioner. En uppfoljning av rapporten sker i "Bjalklag pa jord - varmeisolering och golvtemperaturer", R41 :1973. (Less)
Geomechanics for Energy and the Environment, Dec 1, 2022
I denna studie analyseras och anges metoder att berakna varmeforlusterna mot mark. Varmeforluster... more I denna studie analyseras och anges metoder att berakna varmeforlusterna mot mark. Varmeforlusterna erhalls med hjalp av formler, diagram och tabeller. Effekten av olika kantisoleringar, andringar av ute- och innetemperaturer, koldknappar, tjale och sno beraknas samt varmeforluster vid ny byggnad under uppbyggnad av varmekudde.
Energy Geotechnics, Aug 24, 2018
For around two decades of research and development in the field of grouting in hard jointed rock,... more For around two decades of research and development in the field of grouting in hard jointed rock, the design process has taken some leaps forward. Stille and Gustafson, 2005 and Funehag and Gustafson 2008, shows how a grouting design can be computed. A grouting design in hard rock can based on the penetration length of grout in rock fractures. The design comprises considerations of the fracture apertures in the rock mass, the type of grout and its rheological properties and how the grout is injected i.e pressure and grouting times. When knowing these parameters an optimized geometry fitting the design is made. Thorn, et al, 2014 describes a fundamental analysis with a comprehensive tool to retrieve the fracture distribution and aperture distribution of the fractures crossing a cored borehole. The data needed about the core is geological mapping and hydraulic section tests. In Gustafson, Claesson and Fransson, (2013) a full derivation of a radial Bingham flow in a slit is described for constant pressure. By optimizing with a specific pressure and an efficient grouting time (efficient time means the time when the pressure has reached the designed pressure) a prognosis a more realistic time consumption for grouting can be computed. However, the time it takes to reach a certain pressure is dependent on the capacity of the pump and the how large the fractures widths are. For poorly chosen pumps together with large fractures the time to reach the design pressure can be significant. The overall objective for this new formulation was to involve the grouting pressure as a variable rather than constant. A pressure build-up mimic more a realistic pumping scenario which enables better prognosis of grouting works. This paper brings up this new formulation of the radial Bingham flow with variable injection pressure in slit. The benefits of this new formulation is that it can easily be integrated in other computer programs. One program that uses this new formulation is a grouting simulator owned and developed by Edvirt AB. The simulator has been used to pedagogically demonstrate how a variable pressure and restrictions in grout flow (the pump capacity) affect the penetration length. Further, the results show that it can be used to predict suitable pump capacity to fit the coming grouting works.
Grundlaggning med "platta pa mark" eller riktigare "bjalklag pa jord" kan ske... more Grundlaggning med "platta pa mark" eller riktigare "bjalklag pa jord" kan ske med kantforstyvad platta eller med platta och grundmurar. Enligt Svensk Byggnorm 67 ar grundlaggningsdjupet enligt huvudregeln 0,25 m. Grundlaggningsdjup maste emellertid knytas till ett stort antal forutsattningar. Genom tillgang till datorberakningsmetoder och stora datorer har det blivit mojligt att noga teoretiskt studera temperaturer och frostnedtrangning. I rapporten granskas olika faktorers inverkan pa frostnedtrangningen. Intill en byggnad ges mojlighet till en mera nyanserad bedomning av frostnedtrangning och grundlaggningsdjup. Ett forslag till andring av Svensk Byggnorm ges ocksa. Genom ett stort antal diagram, baserade pa datorberakningar, ges lasaren mojlighet till bedomning av egna okonventionella konstruktioner. En uppfoljning av rapporten sker i "Bjalklag pa jord - varmeisolering och golvtemperaturer", R41 :1973. (Less)
Geomechanics for Energy and the Environment, Dec 1, 2022
I denna studie analyseras och anges metoder att berakna varmeforlusterna mot mark. Varmeforluster... more I denna studie analyseras och anges metoder att berakna varmeforlusterna mot mark. Varmeforlusterna erhalls med hjalp av formler, diagram och tabeller. Effekten av olika kantisoleringar, andringar av ute- och innetemperaturer, koldknappar, tjale och sno beraknas samt varmeforluster vid ny byggnad under uppbyggnad av varmekudde.
Energy Geotechnics, Aug 24, 2018
For around two decades of research and development in the field of grouting in hard jointed rock,... more For around two decades of research and development in the field of grouting in hard jointed rock, the design process has taken some leaps forward. Stille and Gustafson, 2005 and Funehag and Gustafson 2008, shows how a grouting design can be computed. A grouting design in hard rock can based on the penetration length of grout in rock fractures. The design comprises considerations of the fracture apertures in the rock mass, the type of grout and its rheological properties and how the grout is injected i.e pressure and grouting times. When knowing these parameters an optimized geometry fitting the design is made. Thorn, et al, 2014 describes a fundamental analysis with a comprehensive tool to retrieve the fracture distribution and aperture distribution of the fractures crossing a cored borehole. The data needed about the core is geological mapping and hydraulic section tests. In Gustafson, Claesson and Fransson, (2013) a full derivation of a radial Bingham flow in a slit is described for constant pressure. By optimizing with a specific pressure and an efficient grouting time (efficient time means the time when the pressure has reached the designed pressure) a prognosis a more realistic time consumption for grouting can be computed. However, the time it takes to reach a certain pressure is dependent on the capacity of the pump and the how large the fractures widths are. For poorly chosen pumps together with large fractures the time to reach the design pressure can be significant. The overall objective for this new formulation was to involve the grouting pressure as a variable rather than constant. A pressure build-up mimic more a realistic pumping scenario which enables better prognosis of grouting works. This paper brings up this new formulation of the radial Bingham flow with variable injection pressure in slit. The benefits of this new formulation is that it can easily be integrated in other computer programs. One program that uses this new formulation is a grouting simulator owned and developed by Edvirt AB. The simulator has been used to pedagogically demonstrate how a variable pressure and restrictions in grout flow (the pump capacity) affect the penetration length. Further, the results show that it can be used to predict suitable pump capacity to fit the coming grouting works.