1887

oa Civil Engineer in South Africa - The effects of mining subsidence on discontinuous rock masses and the influence on foundations : the British experience : technical paper

 

Abstract

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 '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 '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.

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/content/civeng1/33/6/EJC25123
1991-06-01
2016-12-04
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