an engineering geological characterisation of tropical clays - GBV

More documents

Recommendations

Info

194 A comparison of laboratory determined linear shrinkage values (LS measured) with those computed (LSLL) according to Equation (10.18) reveals a very strong closeness. The two sets of data are practically identical in terms of maximun and minimum values, the range as well as the median, mode and mean values (Table 10.5). The two comparable standard deviations of 4,30 and 4,02, and very strong correlation of 0,93 are further evidence of the similarity of the two sets of data; and therefore the reliability of the new relationship in estimating linear shrinkage of soils from laboratory measured liquid limits. The relationship between laboratory measured and calculated linear shrinkage values is illustrated diagrammatically in Fig. (10.8), and takes the form of LSmeasured = 0,997LSLL (10.19) LS measured/ LSLL Measured linear shrinkage LSmeas. (%) 35 30 25 20 15 10 5 0 n = 90 R 2 = 0,86 LS meas. = 0,997LSLL Black clays and red soils Linear (Black clays and red soils) 0 10 20 30 Calculated linear shrinkage LSLL (%) Figure 10.8. A correlation between calculated and laboratory determined linear shrinkage of black clays and red soils. 10.4 Free swell and other index properties The Swelling capability of black clays and red soils could be estimated with a high degree of approximation (R² = 0,85 and over) from laboratory results of Atterberg limits and linear shrinkage. The form and strength of correlation between laboratory determined free swell (FS) on one hand; and liquid limits (LL), plasticity index (PI) and linear shrinkage (LS) of the soils on the other, are illustrated in Table (10.6) and Fig. (10.9).
195 Table 10.6. Calculated and laboratory measured free swell values of black clays and red soils. Profile Sample No. FS (%) LL (%) PL (%) PI (%) LS (%) FSLL (%) FSPI (%) FSLS (%) SA1-30cm 135 78 37 41 25 105 106 131 A SA1-50cm 100 75 36 39 23 95 97 117 SA2-30cm 135 93 39 54 27 151 155 146 (black clays) SA2-70cm 170 90 36 54 25 143 154 131 SA2-105cm 120 88 33 55 26 137 160 139 SA28-30cm 125 85 40 45 25 126 122 131 SA28-50cm 135 89 41 47 25 138 130 131 SA37-30cm 115 81 38 43 24 114 113 124 SA37-50cm 115 83 39 44 26 121 118 139 SA37-80cm 115 85 39 46 26 127 125 139 SA41-30cm 135 89 41 47 26 138 130 139 SA41-50cm 120 90 41 49 24 142 135 124 SB1-30cm 125 82 34 47 23 116 130 117 B SB1-50cm 135 84 36 48 24 123 131 124 SB1-70cm 145 90 39 51 25 142 143 131 (black clays) SB5-30cm 120 81 34 47 23 114 129 117 SB5-50cm 135 85 37 48 24 126 133 124 SB5-70cm 145 91 40 51 26 146 144 139 SB7-30cm 130 83 35 48 24 120 134 124 SB7-50cm 135 86 37 49 24 129 136 124 SB7-70cm 140 87 38 49 25 133 135 131 SB18-30cm 120 82 40 43 23 119 112 117 SB18-50cm 120 72 34 39 21 87 98 102 SB27-30cm 130 85 38 47 24 127 129 124 SB27-50cm 130 88 39 49 25 135 135 131 SB31-30cm 130 87 38 49 24 133 136 124 SB31-50cm 130 86 38 48 25 130 134 131 SB41-30cm 145 89 45 44 26 139 118 139 SB41-50cm 145 91 44 47 25 145 129 131 SB42-30cm 145 88 44 44 25 135 117 131 SB42-50cm 145 91 45 47 26 146 127 139 SC1-30cm 125 82 35 48 23 117 131 117 C SC1-50cm 135 85 37 48 24 126 133 124 SC5-30cm 125 83 35 48 23 121 134 117 (black clays) SC5-50cm 135 84 36 47 24 122 130 124 SC9-30cm 130 84 36 48 24 122 133 124 SC9-50cm 135 85 37 48 24 126 131 124 SC17-30cm 105 76 35 41 25 97 106 131 SC17-50cm 110 81 33 48 24 113 133 124 SC25-30cm 125 88 39 49 25 136 136 131 SC25-50cm 145 89 41 48 25 138 131 131 SC29-30cm 110 82 32 49 25 116 138 131 SC29-50cm 110 80 37 43 26 112 115 139 SC33-30cm 120 82 33 49 25 116 137 131 SC33-50cm 120 83 33 50 26 120 140 139 SC41-30cm 125 85 38 47 29 127 130 160 SC41-50cm 125 84 37 47 29 122 129 160
Page 1 and 2:
AN ENGINEERING GEOLOGICAL CHARACTER
Page 3 and 4:
i Contents Page Acknowledgements Su
Page 5 and 6:
iii Chapter 8. Distribution of inde
Page 7 and 8:
v 7.29 - 7.33 Correlation between s
Page 9 and 10:
vii 136 139 7.13 Compressibility cl
Page 11 and 12:
ix Acknowledgements I would like to
Page 13 and 14:
1 Chapter 1 Introduction 1.1 Scope
Page 15 and 16:
Figure1.1 Map of Nairobi region sho
Page 17 and 18:
5 Plates 1.2 (a) & (b) Strong shrin
Page 19 and 20:
7 Available literature in the form
Page 21 and 22:
9 slopes. The northern boundary bet
Page 23 and 24:
11 1.6 Climate The Nairobi area and
Page 25 and 26:
13 marked daily range of relative h
Page 27 and 28:
15 Chapter 2 Previous works 2.1 Sum
Page 29 and 30:
17 Table 2.1 Stratigraphic correlat
Page 31 and 32:
19 Chapter 3 Geology 3.1 Introducti
Page 33:
21 metamorphic minerals sillimanite
Page 37 and 38:
25 and prismatic apatite occur as a
Page 39 and 40:
27 Table 3.2 Chemical analyses of s
Page 41 and 42:
29 caused by partial segregation of
Page 44 and 45:
32 could otherwise lead to erroneou
Page 46 and 47:
34 The red soils in this study occu
Page 48 and 49:
36 17 16 15 14 13 12 11 10 9 8 7 6
Page 50 and 51:
38 4.4 Vane test 4.4.1 Introduction
Page 52 and 53:
40 Table 4.1 Classification of soft
Page 54 and 55:
42 The variation of vane shear stre
Page 56 and 57:
44 And thirdly, the field vane appa
Page 58:
46 horizon, most probably a result
Page 61 and 62:
49 The red friable clays on the who
Page 63 and 64:
51 Results of chemical analyses of
Page 65 and 66:
53 Results of previous soil classif
Page 67 and 68:
55 neighbouring metamorphic areas a
Page 69 and 70:
57 Table 5.10. Profile description
Page 71 and 72:
59 The presence of BaO in the red a
Page 73 and 74:
61 resulted most probably from supp
Page 75 and 76:
63 800 Impulse 700 600 500 SC 17 -5
Page 77 and 78:
65 sericite and chlorite (see next
Page 79 and 80:
67 Q: Quartz (1%) H: Haematite K: K
Page 81 and 82:
69 Plate 6.3. K-feldspar phenocryst
Page 83 and 84:
71 The trachytes generally show a r
Page 85 and 86:
73 Plate 6.16. Organic matter (rema
Page 87 and 88:
75 Plate 6.24. Solution pores/ cavi
Page 89 and 90:
77 Plate 6.29. Iron concretion with
Page 91 and 92:
79 The CS-225 is a micro-processor
Page 93 and 94:
81 The red soils generally exhibit
Page 95 and 96:
83 Chapter 7 Laboratory soils index
Page 97 and 98:
85 According to Johnson and Degraff
Page 99 and 100:
87 Table 7.2. Results of index test
Page 101 and 102:
89 Plate 7.2a. Apparatus for liquid
Page 103 and 104:
91 Activity chart Plasticity index
Page 105 and 106:
93 Table 7.3 (continued). Atterberg
Page 107 and 108:
95 where 7.1.4.4 Results V = volume
Page 109 and 110:
97 A standard classification of soi
Page 111 and 112:
99 Table 7.6. Viscosity and density
Page 113 and 114:
101 Table 7.7, continued. Results o
Page 115 and 116:
103
Page 117 and 118:
105 Plate 7.7a. Shear testing showi
Page 119 and 120:
107 Shear stress / Displacement Cur
Page 121 and 122:
109 Table 7.10. Distribution and/ o
Page 123 and 124:
111 illustrated in Figures 7.6, 7.7
Page 125 and 126:
113 Black clays Cohesion c´ (kN/m
Page 127 and 128:
115 7.4 Oedometer consolidation tes
Page 129 and 130:
117 The compound coefficient, K/ρw
Page 131 and 132:
119 Primary consolidation is a time
Page 133 and 134:
121 where w (%) = moisture content
Page 135 and 136:
123 Relationships between values of
Page 137 and 138:
125 Plate 7.8. Oedometer consolidat
Page 139 and 140:
127 Cumulative log-time/settlement
Page 141 and 142:
129 Ranges of values of coefficient
Page 143 and 144:
131 is most probably due to the ten
Page 145 and 146:
133 The results of correlation show
Page 147 and 148:
135 by differences in lithology, mi
Page 149 and 150:
137 Black clays and red soils Swell
Page 151 and 152:
139 Testing procedure involved cutt
Page 153 and 154:
141 Black clays Swelling pressure S
Page 155 and 156: 143 Black clays: P (kPa) vs S (%) P
Page 157 and 158: 145 The same relationship is repres
Page 159 and 160: 147 Alternatively, percentage swell
Page 161 and 162: 149 Combined sample results: S % vs
Page 163 and 164: 151 Black clays: Greek method P% =
Page 165 and 166: 153 partly produced by effects of w
Page 167 and 168: 155 Chapter 8 Distribution of index
Page 169 and 170: 157 the study area, respectively. R
Page 171 and 172: 159 Liquid limit variation; 0,50m a
Page 173 and 174: 161 Liquid limit (LL) variation (>
Page 175 and 176: 163 (8.6). The few isolated patches
Page 177 and 178: 165 Similarly, soil thicknesses of
Page 179 and 180: 167 Free swell variation; 0,50m dep
Page 181 and 182: 169 fraction at the two depth inter
Page 183 and 184: 171 Variation of fines (%), < 0,50m
Page 185 and 186: 173 %coarse % coarse fraction varia
Page 187 and 188: 175 1°19´S 22 Shear angle variati
Page 189 and 190: 177 9.2 Grain size distribution The
Page 191 and 192: 179 rapid dissipation of pore water
Page 193 and 194: Chapter 10 181 Correlation of index
Page 195 and 196: 183 Black clays; plasticity index/
Page 197 and 198: 185 On the other hand, laboratory m
Page 199 and 200: 187 Red clays; measured/ calculated
Page 201 and 202: 189 These two relationships could b
Page 203 and 204: 191 Diagram: PImeasured/ PIcalculat
Page 205: 193 Table 10.5, continued. Calculat
Page 209 and 210: 197 The swelling capability in term
Page 211 and 212: 199 Free swell/ clay fraction Free
Page 213 and 214: 201 There has also been a decrease
Page 215 and 216: 203 PI = 1,88*LS A comparison of pl
Page 217 and 218: 205 cc = 0,0099(122-LL) for black c
Page 219 and 220: 207 Chapter 12 Recommendations Anal
Page 221 and 222: 209 cc = 0,0099(122-LL) for black c
Page 223 and 224: 211 References Abebe, S. T., 2002.
Page 225 and 226: 213 Galster, R.W., 1977. A system o
Page 227 and 228: 215 Mitchell, J.K., 1993. Fundament
Page 229 and 230: 217 ------,1964. Long term stabilit
Page 231 and 232: Appendix A: Oedometer consolidation
Page 233 and 234: Table A7. Consolidation parameters
Page 235 and 236: Results of swelling tests on black
Page 237 and 238: Appendix D Distribution/ variation
Page 239 and 240: 4000 3000 2000 Distance (m) 1000 We
Page 241 and 242: 4000 3000 2000 1000 Distance (m) We
Page 257 and 258:
4000 3000 2000 Distance (m) 1000 We
Page 259 and 260:
Appendix E Geotechnical soil map of
show all

an engineering geological characterisation of tropical clays - GBV

Create successful ePaper yourself

Delete template?

Save as template?