Volkswagen Beetle Dethroned As America's Geekiest Car – News – Car and Driver
Joe Kohen, Robert Laberge/Getty Images, Best Buy Volume 33, Issue 6, 1991 Civil Engineer in South Africa - Volume 33, Issue 6, June 1991 Navigate this Journal About Previous issues Volumes & issues
Volume 34 (1992) Volume 33 (1991) Volume 32 (1990) Volume 30 (1988) Volume 29 (1987) Volume 27 (1985) Volume 26 (1984) Volume 25 (1983) Volume 24 (1982) Volume 23 (1981) Volume 22 (1980) Volume 21 (1979) Volume 33, Issue 6, June 1991 (0)
The effects of mining subsidence on discontinuous rock masses and the influence on foundations : the British experience : technical paper
F.G. Bell and
Civil Engineer in South Africa 33, pp 201 –210 (1991)
Discontinuities are characteristic features of the competent rock masses such as standstones and limestones, which occur in the Coal Measures of Britain and the overlying Permian and Triassic systems. The longwall method used to extract coal subjects the strata above the seam to stresses that can cause discontinuities to open or widen significantly. Unfortunately, however, the degree to which discontinuities open or gape and the behaviour of discontinuous blocks cannot be predicted. Some discontinuities opened by tension may close, at least in part, when undergoing compressive stress. Overlying soils may be washed into discontinuities that gape and this may give rise to depressions. These, together with gaping joints, may give rise to foundation problems. The paper reviews some methods of foundation treatment that can be used to overcome the problems outlined above. It also briefly reviews two case histories relating to special foundations on sites affected by discontinuities and subsidence.
Diskontinuiteite is &apos;n kenmerkende eienskap van kompetente rotsliggame soos sandstene en kalkstene wat in die steenkoolmyne van Brittanje en die oorliggende Permiaanse en Triassiese sisteme voorkom. Die langwal-metode wat gebruik word om steenkool te myn, onderwerp die strata bokant die steenlaag aan spanning wat diskontinuiteite kan veroorsaak of beduidend verbreed. Ongelukkig is die mate van opening en die gedrag van onderbroke blokke nie voorspelbaar nie. Sekere diskontinuiteite wat deur spanning oopgemaak is, kan heeltemal of gedeeltelik toemaak as hulle kompressie ondergaan. Boliggende grond kan in diskontinue gapings ingewas word en daardeur kan oppervlakholtes vorm. Saam met gapende holtes mag dit probleme met fondamente veroorsaak. Die referaat gee &apos;n oorsig van sommige metodes van fondament-behandeling wat gebruik kan word om bogenoemde probleme te voorkom. Twee gevalle-studies word opsommenderwys gegee wat te make het met spesiale fondamente op terreine geaffekteer deur diskontinuiteite en versakking.
&apos;n Minisirkel-demonstrasieprojek in Pretoria : technical paper
S.C. Van As and
Civil Engineer in South Africa 33, pp 211 –216 (1991)
Verkeersirkels as &apos;n vorm van kruisingbeheer bestaan al vanaf die begin van die eeu en is veral in Brittanje baie gewild. Kleiner sirkels is egter grootliks afgeskeep in Suid-Afrika. Alhoewel daar al dikwels aangetoon is dat verkeersirkels voordelig is in terme van padgebruikerskoste, word stellings nog gemaak dat &apos;minisirkels nie in Suid-Afrika sal werk nie&apos;. &apos;n Onlangse demonstrasieprojek in Pretoria het egter getoon dat minisirkels &apos;n hoe mate van aanvaarbaarheid onder motoriste kan verwerf.
The concept of traffic circles as a form of intersection control has been in existence since the turn of the century and is especially popular in Britain. Smaller circles have, however, not been fully exploited in South Africa. Although it has been shown that traffic circles are beneficial in terms of road-user costs, statements are frequently made to the effect that &apos;mini-circles will not work in South Africa&apos;. A recent demonstration project in Pretoria has, however, shown that mini-circles can achieve a high degree of acceptance among motorists.