an engineering geological characterisation of tropical clays - GBV

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Tables
1.1 Mean maximum and minimum temperatures for each month of the
year over a period of 50 years, for Nairobi city and the present study area 11
1.2 Average rainfall, mean relative humidity and amount of bright sunshine
for each month of the year, for Nairobi city and the present study area 12
2.1 Stratigraphic correlation of rocks in the Nairobi region 17
3.1 Chemical analyses of alkali-feldspars from the Kapiti phonolite
and similar rocks 25
3.2 Chemical analyses of strongly alkaline lavas of Nairobi phonolite
and other rocks 27
3.3 Chemical analyses of mildly alkaline lavas of Nairobi trachyte
and other volcanic rocks 28
3.4 Mineral compositions of trachytes and phonolites from Nairobi and
the study area 29
4.1 Classification of soft soils based on vane shear strength 40
4.2 Results of field vane shear tests in soft black clays at Madaraka West 40
4.3 Results of field vane shear tests in soft red soils at Arboretum 40
4.4 Results of field vane shear tests in soft red soils at Kenya High School 41
5.1 Profile description of a red friable clay 49
5.2 Soluble base content in soils of the study area 49
5.3 Profile description of a shallow yellow-brown clay overlying laterite 50
5.4 Results of chemical analyses of red soils obtained in this study 51
5.5 Earlier results of chemical analyses of clays and red soil 52
5.6 Some results of soil classification tests on red soils in present study 52
5.7 Earlier results of soil classification tests on red clays from the Nairobi area 53
5.8 Results of chemical analyses of black clays obtained in this study 54
5.9 Clay mineral composition of black clays 56
5.10 Profile description of black clay 57
6.1 Results of chemical analyses of red soils obtained in this study 58
6.2 Results of chemical analyses of black clays obtained in this study 59
6.3 Clay mineral composition of black clays 61
6.4 Estimated mineralogical composition of red soils 64
6.5 Theoretical compositions of kaolinite, illite and montmorillonite 65
6.6. Carbon content of soils of the study area 80
7.1 Activity of clay soils and clay minerals 85
7.2 Results of index tests performed on black clays and red soils 87-88
7.3 Atterberg limits, activity/ free swell classification and assessment
of possible clay mineralogy of black clays and red soils 92
7.4 Free swell classification of clay soils (Gibbs & Holtz, 1956) 94
7.5 Soil classification by particle size (BS 1377: 1975) 97
7.6 Viscosity and density of water (Kaye and Laby, 1973) 99
7.7 Results of grain size analysis for black clays and red soils 100-101
7.8 Typical values of φ for dry noncohesive soils and clay (after Lambe and
Whitman, 1979) 106
7.9 Shear strength parameters of black clays and red soils 108
7.10 Distribution and/variation of shear strength parameter (φ´) across study area 109
7.11 Time factors for one-dimensional consolidation (Leonards, 1962) 117
7.12 Derived parameters from results of oedometer consolidation tests
for the loading range of 25-800 kPa 128