Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Geotextiles perform a number of functions in various applications in civil engineering practise. It is often cost effective and more environmentally friendly versus conventional
construction methods. One of the main functions of a geotextile is filtration whereby the
geotextile is expected to hold back the soil particles and simultaneously has to allow
sufficient water to pass through it. Soils are all different and can be problematic when it
comes to designing geotextile filters. One such problematic soil is encountered in KwaZulu-
Natal, situated along the east coast of South Africa. The Berea sand is problematic as it can
highly variable in its engineering properties over a small area.
Geotextiles are becoming more and more common practice in South Africa and little is
known about the filtration performance of commercially available geotextiles in conjunction
with Berea sand. Local guidelines that are available are out of date and do not provide
enough information to assist design engineers in decision making. Many international
guidelines are available and it is difficult to choose which one is best suited to Berea sands.
This primary objective of this study is to investigate the filtration performance of four variants
of commercially available geotextiles and three variants of Berea sand. The applicability of
some of the international filter design criteria will also be assessed. The soil to geotextile
compatibility testing was carried out as per ASTM D5101 (2006) - Standard Test Method for
Measuring the Soil-Geotextile System Clogging Potential by the Gradient Ratio. In total 12
permutations were executed. The results showed that only 5 test permutations met the
gradient ratio and permeability criteria. The test results also conclude that the permeability is
just as important as the gradient ratio. Thick geotextiles should be considered when used as
filters in Berea sands. The available international geotextile filter design criteria were
assessed and all showed poor correlation between laboratory results and suggested criteria.
Designing geotextile filters in conjunction with Berea reds is challenging and it is
recommended that design engineers perform laboratory performance testing in conjunction
with their designs. / AFRIKAANSE OPSOMMING: Geotekstiele verrig vir 'n aantal funksies in verskeie programme in die siviele
ingenieurswese praktyk. Dit is dikwels meer koste-effektief en omgewingsvriendelik, teenoor
konvensionele konstruksie metodes. Een van die belangrikste funksies van 'n geotekstiel is
filtrasie, waardeur van die geotekstiel verwag word om van die grond terug te hou, en
gelyktydig genoeg water daardeur te laat vloei. Grond verskil en dit kan problematies wees
wanneer dit kom by die ontwerp van geotekstiel filters. Een so ‘n problematiese grond kom
voor in KwaZulu-Natal, geleë langs die ooskus van Suid-Afrika. (Die) Berea sand is
problematies, want dit verander geweldig baie ten opsigte van ingenieurseienskappe oor 'n
redelike klein area. Gebruik van geotekstiele word al hoe meer ‘n algemene praktyk in Suid-
Afrika, terwyl min bekend is oor die filtrasie prestasie van kommersieel beskikbare
geotekstiele in samewerking met Berea sand. Plaaslike riglyne wat beskikbaar is, is verouderd en onvoldoende inligting is beskikbaar aan
ontwerpingenieurs vir besluitneming . Baie internasionale riglyne is beskikbaar en dit is
moeilik om te besluit watter een die beste van toepassing is vir Berea sand. Die doel van
hierdie studie is om die filtrasie prestasie van vier modelle van kommersieël beskikbare
geotekstiele en voorbeelde van drie soorte Berea sand te ondersoek. Die toepaslikheid van
'n paar van die internasionale filter ontwerp kriteria sal ook beoordeel word. Die toetsing van
grondverenigbaarheid met geotekstiel is uitgevoer soos aangedui in ASTM D5101 (2006 ) –
Standaard Toets Metode vir die meet van die grond-Geotekstiel verstopping potensiëel deur
die gradient verhouding. In totaal is 12 permutasies uitgevoer. Die resultate het getoon dat
slegs 5 toetspermutasies beide gradiënt verhouding en permeabiliteit kriteria bevredig het.
Dikker geotekstiele word ook aanbeveel vir gebruik as filters in Berea sand. Van die toets
resultate kan ook afgelei word dat die permeabiliteit net so belangrik soos die gradiënt
verhouding is. Beskikbare internasionalegeotekstiel filter ontwerp kriteria is nagegaan en al
die metodes het swak korrelasie tussen laboratorium resultate en die voorgestelde kriteria
getoon.
Om geotekstiel filters in samewerking met Berea Reds te ontwerp is 'n uitdaging en dit word
aanbeveel dat ontwerpingenieurs laboratorium prestasietoetsing in samewerking met hul
ontwerpe uitvoer.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86381 |
| Date | 04 1900 |
| Creators | November, Justin Sidney |
| Contributors | De Wet, M., Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xxi, 176 p. : ill. |
| Rights | Stellenbosch University |
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