1887

oa Civil Engineer in South Africa - The prediction of the California bearing ratio : technical paper

Volume 32, Issue 12
  • ISSN : 0009-7845

 

Abstract

The California bearing ratio (CBR) test for road pavement materials has remained popular for over 50 years. It is a lengthy and relatively expensive test and attempts have been made over the years to substitute it with mathematical or graphical models that utilize soil classification parameters such as grading and Atterberg limits to predict the CBR. This paper details an investigation in which archival data were used to evaluate the existing models for some selected Natal soils, and describes how the relationships between CBR and various classification parameters (in both simple and multivariate forms) were further examined when these models were found to be generally unsatisfactory. The lack of any correlations suitable for use in a universally applicable prediction model is discussed, the good relationship between CBR and maximum swell is examined, further research into the influence of the clay fraction on CBR prediction is reported and the interim use of the shrinkage and grading moduli to obtain minimum CBR values for shrinking and non-shrinking soils respectively is proposed.

Die Kaliforniese drakragverhouding (KDV)-toets vir padplaveiselmateriale het oor meer as 50 jaar populer gebly. Dit is 'n lang en relatief duur toets, en daar was dus oor die jare pogings om wiskundige of grafiese modelle voor te stel wat voorspelde KDV-waardes deur middel van grondklassifikasieparameters soos gradering of die Atterberg-limiete voorsien. Die verhandeling gebruik argiefsdata om die bestaande modelle vir sekere geselekteerde grondtipes te evalueer en dui aan hoe die verband tussen die KDV en verskillende klassifikasieparameters verder ondersoek is (in beide enkel- en multivariante vorme) toe hierdie modelle in die algemeen onbevredigend gevind is. Die gebrek aan enige paslike korrelasies vir gebruik in 'n algemene voorspelmodel word bespreek, die goeie verhouding tussen KDV en maksimum uitswelling word ondersoek, verdere narvorsing oor die invloed van die kleifraksie op KDV-voorspelling word gerapporteer en die tussentydse gebruik van die krimp- en graderingmoduli om minimum KDV-waardes van krimpende en nie-krimpende gronde te bekom, word voorgestel.

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/content/civeng1/32/12/EJC25093
1990-12-01
2016-12-11

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