Determination of pullout resistance of galvanized-steel strips within select South African soils based on their free draining potential in mechanically stabilized earth wall backfill conditions

Hoffman, Kyle (2019-12)

Thesis (MEng)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: Water distribution systems around the world typically comprise a large number of pipelines designed to distribute pressurised water. These pipelines stretch over long distances and vary in diameter, material, wall thickness, internal roughness and age. By nature, these systems are extremely complex and require expert knowledge and specialised tools to be modelled and designed correctly. Furthermore, these networks encompass multiple parameters such as available supply pressures, internal roughness coefficients, frictional losses, annual average daily demands and instantaneous peak hour factors. In order to efficiently manage all of these variables, engineers require a substantial volume of data and sophisticated computer modelling software. Considering this, the following research question was identified: “Can one develop an urban network capacity model by considering only the network’s physical characteristics?” Or more simply, if sufficient knowledge about a reticulation network’s physical parameters are known, can these parameters be used to model certain other parameters associated with a water network? Therefore, the aim of this project was to develop a “network capacity model” by analysing the relevant physical parameters of many existing water reticulation network models. The parameters that were identified and could potentially impact the overall supply zone capacity include: total pipeline length, total pipeline volume, average pressure, supply zone topology, supply zone shape, supply zone area, land use and distance from supply position to the centroid of the supply zone. Three linear regression approaches, namely Multi Linear Regression, Principal Component Analysis and Partial Least Squares were used to test this relationship and determine the most accurate model. The model that was generated following application of these analyses, presents significant advantages to engineers, and enable options that were never before possible. If the future water demand of an area is known or can be estimated, the model could be used to reverse engineer a list of the required pipe diameters and associated pipe lengths that could meet this demand. For the first time, it now becomes possible to provide a fairly accurate water network cost estimate for future development areas, without the availability of a street layout. This model also holds the potential to be implemented in developing countries where the necessary skills or resources are not always available to compile computerised models of water distribution networks. In these developing areas, a manual model with simple input parameters can be a reliable and useful tool to manage and plan for expanding water networks. Furthermore, it has the potential for application in the field of asset management to provide a breakdown of the various pipe diameters and their respective pipe lengths (for purposes of establishing a technical asset register). In this sense it could be used in areas where water networks exist, but where the water network drawings or detailed water network models may not be available. In these instances, the model may be used to provide an estimate of the pipelines and overall replacement cost of the water reticulation network.

AFRIKAANSE OPSOMMING: Waterverspreidingsnetwerke wêreldwyd bestaan tipies uit ‘n groot aantal pyplyne wat ontwerp word om water onder druk te vervoer. Hierdie pyplyne strek oor lang afstande, en varieer in diameter, materiaal, wanddikte, interne ruheid en ouderdom. Gegewe die inherente komplekse aard van hierdie netwerke, word spesialiskennis en –sagteware benodig vir die modellering en ontwerp daarvan. Parameters soos beskikbare verspreidingsdruk, interne ruheidskoëffisiënte, wrywingsverliese, gemiddelde jaarlikse waterverbruik en piekfaktore moet tipies in ag geneem word. Om die impak van al hierdie veranderlikes korrek te bestuur, benodig die ingenieur toegang tot ‘n groot hoeveelheid data en gevorderde rekenaarpakkette. Gegewe hierdie uitdagings, is die volgende navorsingsvraag geïdentifiseer: “Kan ‘n netwerkkapasiteitsmodel ontwikkel word deur bloot die fisiese eienskappe van die netwerk in ag te neem?” Of meer simplisties, indien genoegsame inligting bestaan rakende die fisiese eienskappe van ‘n gegewe waternetwerk, kan hierdie eienskappe gebruik word om sekere ander, onbekende eienskappe te bepaal? Die mikpunt van hierdie studie is dus om ‘n stedelike netwerkkapasiteitsmodel te ontwikkel deur ontleding van die toepaslike veranderlikes van ‘n groot aantal bestaande waternetwerke. Die parameters wat geïdentifiseer is wat moontlik die kapasiteit van ‘n waternetwerk kan beïnvloed sluit in totale pyplynlengte, totale pyplynvolume, gemiddelde druk, topologie van die verspreidingsarea, vorm van die verspreidingsarea, oppervlakte van die verspreidingsarea, grondgebruik en die afstand van die punt van lewering tot by die sentroïde van die verspreidingsarea. Drie verskillende analises is toegepas, naamlik multi-liniêre regressie, hoofkomponent regressie en gedeeltelike minste vierkante regressie. Die oogmerk was om moontlike verwantskappe te identifiseer en die mees akkurate model te ontwikkel. Die model wat op sodanige wyse ontwikkel was, hou groot voordele vir ingenieurs in, en ontsluit moontlikhede wat tot op hede nie beskikbaar was nie. Indien die toekomstige waterverbruik van ‘n area beskikbaar is of beraam kan word, kan die gebruiker die totale benodigde pyplengte en verwante diameters met ‘n groot mate van sekerheid voorspel. Dit word sodoende vir die eerste keer moontlik om ‘n redelike akkurate watermeesterplan vir toekomstige uitbreidings te ontwikkel, selfs in omstandighede waar die toekomstige straatuitleg nie beskikbaar is nie. Dit bemoontlik ook kosteberamings en verwagte konstruksietyd vir die ontwikkeling van waternetwerke vir hierdie areas. Die model het ook moontlike toepassing in onwikkelde lande, waar die nodige kundigheid en hulpbronne wat benodig word om waternetwerk rekenaarmodelle te ontwikkel dikwels ontbreek. In hierdie omstandighede vergemaklik die eenvoud van die toepassing van die model die bestuur en beplanning van die uitbreiding van waternetwerke. Die model kan ook gebruik word vir batebestuur, veral in areas waar waternetwerke bestaan, maar die inligting of netwerkmodelle ontbreek. In hierdie omstandighede kan die model gebruik word om met redelike sekerheid te bepaal hoe die netwerk waarskynlik daaruit sien en wat die totale batewaarde van sodanige waternetwerk behoort te wees.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/107097
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