an engineering geological characterisation of tropical clays - GBV

More documents

Recommendations

Info

156 Table 8.1. Values of index properties of soils along field profiles in this study. Profile Depth (m) Sample No. Sta. position (m) Wn (%) LL (%) PI (%) LS (%) FS (%) Depth (m) Sample No. Wn (%) LL (%) PI (%) SA1-30cm 0 32 78 41 25 135 SA1-50cm 30 75 39 23 100 SA2- A < 0,50 SA2-30cm 250 34 93 54 27 135 ≥ 0,50 70/105cm 32 89 55 26 145 SA28-30cm 6750 26 85 45 25 125 SA28-50cm 27 89 47 25 135 SA37- SA37-30cm 9000 19 81 43 24 115 50/80cm 23 84 39 26 115 SA41-30cm 10000 23 89 47 26 135 SA41-50cm 25 90 49 24 120 SB1-30cm 0 23 82 47 23 125 SB1-50/70cm 29 87 50 25 140 B < 0,50 SB5-30cm 1000 24 81 47 23 120 ≥ 0,50 SB5-50/70cm 29 88 50 25 140 SB7-30cm 1500 23 83 48 24 130 SB7-50/70cm 28 87 49 25 138 SB18-30cm 4250 20 82 43 23 120 SB18-50cm 20 72 39 21 120 SB27-30cm 6500 22 85 47 24 130 SB27-50cm 22 88 49 25 130 SB31-30cm 7500 23 87 49 24 130 SB31-50cm 23 86 48 25 130 SB41-30cm 10000 23 89 44 26 145 SB41-50cm 24 91 47 25 145 SB42-30cm 10250 22 88 44 25 145 SB42-50cm 21 91 47 26 145 SC1-30cm 0 24 82 48 23 125 SC1-50cm 26 85 48 24 135 C < 0,50 SC5-30cm 1000 23 83 48 23 125 ≥ 0,50 SC5-50cm 25 84 47 24 135 SC9-30cm 2000 25 84 48 24 130 SC9-50cm 26 85 48 24 135 SC17-30cm 4000 21 76 41 25 105 SC17-50cm 22 81 48 24 110 SC25-30cm 6000 26 88 49 25 125 SC25-50cm 26 89 48 25 145 SC29-30cm 7000 21 82 49 25 110 SC29-50cm 20 80 43 26 110 SC33-30cm 8000 20 82 49 25 120 SC33-50cm 21 83 50 26 120 SC41-30cm 10000 18 85 47 29 125 SC41-50cm 17 84 47 29 125 SD1-30cm 0 27 82 46 26 125 SD1-50/80cm 29 87 48 27 135 D < 0,50 SD5-30cm 1000 26 84 47 26 125 ≥ 0,50 SD5-50/70cm 29 88 49 27 135 SD7-30cm 1500 27 84 48 27 110 SD7-50/70cm 29 89 51 26 138 SD17-30cm 4000 20 84 44 24 120 SD17-50cm 22 84 49 25 130 SD25-30cm 6000 22 80 39 25 125 SD25-50cm 21 86 45 25 135 SD29-30cm 7000 18 85 47 27 125 SD29-50cm 22 86 51 26 145 SD33-30cm 8000 20 85 47 27 125 SD33-50cm 21 86 50 25 145 SD41-30cm 10000 23 85 46 26 130 SD41-50cm 25 90 49 26 135 SE1-30cm 0 24 82 48 23 125 SE1-50/70cm 29 88 50 25 140 E < 0,50 SE5-30cm 1000 25 85 48 24 125 ≥ 0,50 SE5-50/70cm 28 89 49 26 138 SE13-30cm 3000 21 86 47 24 125 SE13-50cm 24 89 49 25 130 SE21-30cm 5000 25 88 49 25 125 SE21-50cm 26 90 49 26 145 SE29-30cm 7000 22 81 46 25 120 SE29-50cm 23 83 47 26 120 SE37-30cm 9000 21 85 48 24 125 SE37-50cm 22 85 48 25 130 SE41-30cm 10000 22 87 47 25 135 SE41-50cm 21 88 48 26 135 max 34 93 54 29 145 max 32 91 55 29 145 Statistical < 0,50 min 18 76 39 23 105 ≥ 0,50 min 17 72 39 21 100 analysis range 16 17 15 6 40 range 15 19 16 8 45 median 23 84 47 25 125 median 25 87 48 25 135 mode 23 85 47 25 125 mode 29 89 49 25 135 mean 23 84 47 25 126 mean 25 86 48 25 132 std 3,37 3,30 2,78 1,38 8,26 std 3,56 4,11 3,28 1,29 11,33 128,2 var 11,36 10,90 7,74 1,89 68,25 var 12,69 16,86 10,76 1,67 8 cov 9,71 8,28 5,60 1,05 35,52 cov 9,71 8,28 5,60 1,05 35,52 correlation 0,83 0,63 0,63 0,61 0,39 correlation 0,83 0,63 0,63 0,61 0,39 There is a general decrease of moisture content of soils west-eastwards across the study area at depths of less than 0,50m, as well as those at 0,50m and more. This could be attributed to a similar variation in the total thickness of soils which also decreases west-eastwards across the study area, from depths of 1,50-2,0m in the western parts to 0,50-0,70m in the eastern parts of LS (%) FS (%)
157 the study area, respectively. Representation of this moisture variation in contour form is given in Fig. (8.2). Natural moisture (Wn) variation (< 0,5 m) 3234 26 1°19´S 4000 19 23 Profile distance (m) 27 26 27 3000 20 22 18 20 23 23 24 23 20 22 23 23 2000 West 24 25 21 25 22 21 22 1000 24 23 25 21 26 1°21.5´S 0 21 20 18 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 36°49É South Profile distance (m) 36°55É Natural moisture (Wn) variation (> 0,5 m) 36°49É 3032 27 23 25 1°19´S 4000 Wn% 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 Profile distance (m) 29 29 29 22 21 22 21 25 3000 29 29 28 20 22 23 24 2000 West 29 28 24 26 23 22 21 1000 26 25 26 22 26 20 21 17 0 1°21.5´S 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 South Profile distance (m) 36°55É 17 18 19 20 21 22 23 24 25 26 27 28 29 Wn% 30 Fig. 8.2. Contoured representation of distribution and variation of natural moisture content in black clays. The area is dotted with patches of relatively low moisture content (Fig. 8.2) corresponding to increasingly lateritic black clays; as well as those of relatively high moisture content in swampy parts and vicinity of stream and/ or river valleys.
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: 155 Chapter 8 Distribution of index
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 and 206: 193 Table 10.5, continued. Calculat
Page 207 and 208: 195 Table 10.6. Calculated and labo
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 243 and 244:
4000 3000 2000 Distance (m) 1000 We
Page 245 and 246:
4000 3000 2000 Distance (m) 1000 We
Page 247 and 248:
4000 3000 2000 Distance (m) 1000 We
Page 249 and 250:
4000 3000 2000 Distance (m) 1000 We
Page 251 and 252:
4000 3000 2000 Distance (m) 1000 We
Page 253 and 254:
4000 3000 2000 Distance (m) 1000 We
Page 255 and 256:
4000 3000 2000 Distance (m) 1000 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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?