around the tests have aided in developing chilled pipeline. have indic - PDF document

around the tests have aided in developing chilled pipeline. have indicated frost penetration rate the rate of frost Afin d’etudier le comportement d’un pipeline de diamktre, refroidi et enfoui construit une installation experimentale Calgary (Alberta). Cette installation sections experimentales de conduites enfouies operation depuis Cross sections for sections at the Calgary frost heave slope of of heave penetration. The tion ratio the fractional in the soil volume during a time period .freezing process. the control, pipe sections presented in in these figures be divided three zones. INSULATE0 SILT INSULATED GRAVEL Cross sections for the insulated test frost heave fast initial freezing of the frost penetration period lasted three months. Zone roughly between incremental ice-segregation ratio for The third, several years, very low frost penetration rates, range from per cent. the above - - Observed pipe heave and depth frost below bottom Heave and frost the insulated report results Calgary Frost Heave Site create small Control section. freeze plates have been operated the Yukon Territory and development of empirical model. full-scale test freeze plate and the development of empirical model. The data in this experimental results type, as function of two parameters; first, frost penetration rate, secondly, pressure the frost series of incremental heaves. incremental, ice-segregation model requires and frost penetration rate for consideration. The use of development of data for along the pipeline further labora- testing (in full-scale field testing Heave versusfrost penetration. initial period frost penetration 1 region, three Zone tests. These values compared values of full-scale field test Empirical Models for Foothills Pipe Northwest Alaskan Pipe- currently developing empirical models heave due the operation empirical model, For the The data 8, and insulated pipe sections have the placement around the chilled pipe limiting the tration depth and the sum- warming effects negated heave built winter season. full-scale test site tions have been from the test site. This that the frost penetration plots is very The compari- test plates et al. full-scale tests provides also shown both the helping in empirical models heave testing Can. Permafrost Calgary, Alberta, Field test results chilled pipeline buried in 3rd. Int. Conf. Permafrost, 482 4TH CAN. PEKMAPKOSTCONF. (19RZ) ice system inoperable. Similar occur- Subsoil heave curling rink would than the contains centre columns which would result in structural damage However, because its is restricted summer break the shut down from out- side is circulated through the building. This allows the ground and has tirely eliminated heave problem. Frost Heave basic elements susceptible subsoils, subfreezing temperature, and water freezes, its volume one-tenth. This expansion accounts of a network ice lenses frost-susceptible soils, have significant of fine-grained con- tents, (fraction mm size) water in soil capillary pores suction pressure develops ice lenses the frost sustained in the ice lenses into the face heave this growth would have little effect profile, groundwater supply, buildings result in extreme, make tenance equipment. Arbutus Club Problem In 19641965, the Arbutus Club a regulation- m), rink with its length years later was built having eight basis, allowing only rink initially seasonally, having a three-month ice-free period Both rinks glacial till deposits. Within skaters and maintenance annoying undulations rink surface, increasingly severe with time. measures. First, bedding layer sheet was secondly, the thickness was in low introduced other maintenance problems. ice thickness 7-in. (17.8-cm) ice was maintained in unusually thick ice increasing the working The evaporating condenser its limit and the growth of ice lenses face with mechanical ice-making machines. Ultimate- heave resulted in ice-making system this stage, nine years in April the authors remedial measures tight schedule. Investigation removed by investigation consisted of a bedding (Figure and the test pits sand and gravel base courses surveyed in shown (Figure located in the north-east portion covered slightly over per cent of Heat from ground corridor room had portion free surface assumed gentle ridge, elliptical with m) by heave averaged about 3 (7.6 cm) the peak 2.5-in. (6.4-cm) the peak during the east side of drainage area. Subs- of water surface and under the rink. plugged, because from the condenser could not rink also had sub-floor drainage perforated, corrugated pipes spaced in general, gravel. At east side, where ever, drainage into the typical subsoil section, as revealed in test pit (Figure 3), consisted layer of thick, coarse sand bedding 4-ft (0.9- The natural beneath the base course ranged from brown blue silty clay. The free-draining gravel base course had formed back-up water where ever, the (1.2 m) subsoil contained reticular pure the subsoil, Subsurface section frost-damaged ice rink. remedial measures involved the full depth the frozen backfill under density. Where existing base course material piping could ably in the reconstruction, it was removed temporarily inside the rink. time constraints dence of vate all subsoils ice lenses, this would long time result in water-logged PERMAFROST CONF. of Ice Sheets Skating Rink monitor the The thermo- read-out gauges monitoring the ground tempera- underneath the time. These in the the cooling pipes adjusted as obtain optimum ice sheet ambient temperatures different seasons. operating temperature of 20 6.1 "C). After the rink service, measurements entirely elimi- 6-in. (15.2-cm) reinforced concrete slab was pipes were embedded within, figure skating Curling Rink In the the curlers also noticed of small the rocks. was measured in July 2.5 cm). sport, and does not warrant the had also been used provide auxiliary problem, the club practice of operating curling rink a seasonal a three-month warm summer through open doors. Subsequent surveys have indi- heaving of has been in the Vancouver region the combination thaw temperature problem can geotechnical principles case history of rink restoration penetration into the the authors rier consisting insulating layers brine through under the rink. waste heat the engine energy efficient virtually cost-free conventional systems. a frost-free sub-base additional capital erally small in relation ings, and year-round utilization Obviously, inclusion of more economical of service and costly remedial the owner, Arbutus Club, under the direction Toplass, Manager, Operations. The Stephens, President. Ripley, Klohn International Ltd. heave in ice rinks Build. Digest