Geotechnics in the African Environment - Proceedings of the Tenth Regional Conference for Africa on soil Mechanics & Foundation Engineering and the Third International Conference on Tropical & Residual Soils/Maseru/23-27 September 1991

Table Of Contents

Preface v
Organising Committee vi
Third International Conference on Tropical and Residual Soils
Lateritic soils: Chemical & geotechnical properties 3
JB Queiroz de Carvalho
The role of iron hydroxide in the engineering behaviour of tropical soils 7
A. Sridharan, Sudhakar M Rao, KP Ramanath & HB Nagaraj
The design, construction and behaviour of permanently cased piles as Sua Pan, Botswana 15
AJ Hammond, BG Bulley & GP Byrne
The origin and engineering properties of the Cainozoic pan sediments at Sua Pan, Botswana 23
BC Bulley & AH Hammond
Piles in deep residual clays 31
JP Pellissier
Characteristics of a deeply weathered residual norite 41
BE Hall, PA Legg & TC Partridge
Retention forces for cuts in slopes of limiting equilibrium 49
LD Wesley & Lee Wai Hin
Slope failures associated with the floods of September 1987 and February 199 in Natal and 57
Kwa-Zulu, Republic of South Africa
A van Schalkwyk & Marion A. thomas
Deterioration and rehabilitiation of earth roads in Madagaskar 65
Josè Carlos de O.S Horta & Carlo R. Traverso
Railway embankment failures due to dispersive soils 75
F. Bucker, MW Giger, HS Mawona & AK Zuber
Derivation of inerim performance-related specifications for coarsely graded plastic calcrete 81
basecourse gravels
F. Netterberg & MI Pinard
The extraordinary phenomenon of chemical heaving and its effect on buildings and roads 91
A.A.B Williams
A case history of structural distress on heaving clay: Colinda Primary School 99
H.A.C. Meintjes
Tenth African Regional Conference on Soil Mechanics and Foundation Engineering
1. Engineering geology, waste disposal and the environment
The engineering geology of the Wolwedans Dam 109
G.N Davis
Grouting of dolomite under foundations for a large bridge 117
B.P Wrench & W.F Heinz
An engineering geological rock mass characterization system for tunnelling purposes 123
G.V Price & A. van Schalkwyk
A geohydrological study of the Vaal river north bank for the design of water conservation 141
and seepage control measures
J.R.C Yaters & J.A Wates
The need for proper domestic waste disposal management in developing countries 147
Soil erosion patterns of Mollisols in the Katse Watershed 149
D. Nkalai
2. Roads
The applicability of pavement evaluation and rehabilitation design methods in Botswana 157
C.J van der Merwe & M.I Pinard
Use of the Dynamic Cone Penetrometer (DCP) in the design of road structures 167
M. de Beer
Mechanistic pavement design using a Pencel Pressuremeter (PSPP) 177
P.J Sanders
Factors influencing the compactability and bearing capacity of untreated roadbuilding 185
C.J Semmelink
The long-term durability of lime-treated soils 193
Aggregate durability: Recommended tests and specification limits for road basecourse 197
L.R Sampson
Effects of undermining a gravel road near Secunda by longwalling 205
F.Netterberg & J.N van der Merwe
3. Foundations
Settelement and allowable pressure on sand 215
G.N Rosenthal & R. van der Vlugt
Full scale pile testing under controlled conditions 223
F.Scheele, E.J Sellers & S.J Cowburn
Load transfer function and pile performance modelling 229
J.P Everett
Design and performance: Piled raft foundation beneath the new 26 storey Palace Hotel in 235
Clive Wilson & Zank Zietkiewicz
New options for foundations on heaving clay 243
A.A.B Williams & J.P Pellissier
Development of raft foundations for small structures on heaving clay 249
J.P Pellissier & A.A.B Williams
4. Laboratory and field testing
A comparison of the three swell test procedures 259
H.D Schreiner & J.B Burland
Lateral swelling pressure developed in an active clay 267
A.B Fourie
Microprocessor control of the drained triaxial test 275
C.T Saunders & T.Zwe
Piezocone testing to predict soft soil settlement 283
G.A Jones & E. Rust
A simple field suction measurement probe 291
M.S Crilly, H.D Schreiner & C.S Gourley
5. Dams
Breaching of an earth dam in the Western Cape by piping 301
Clive Wilson & Louis Melis
The use of dynamic replacement and slurry cutt-off key for dam construction on soft organic 313
F.Wagener, t. Hughes & E. Friedlander
Countering potential piping at an earth dam on dispersive soils 321
C.F Watermeyer, B.E Hall & G.R Botha
6. The Lesotho Highlands scheme: Geotechnical engineering aspects
Geotechnical investigation for Katse dam, Lesotho 331
I.J.A Brackley, S. Wallace, R.M Galliers & M. Lephoma
Lesotho highlands scheme - Compactability problems of crushed stone 343
G.C van Nieker & A. Weyers
Expected engineering geology of the Transfer Tunnel 351
R.M Galliers, I.J.A Brackley, M.Lephoma & A.B Simpson
Reinforced Earth in the Lesotho Highlands water scheme 359
G.M Bentel & A.C.S Smith
7. Problem soils
A case study of the effects of unsuitable foundations for residential dwellings constructed 367
on collapsing sands and the remedial measures required
A. Tanner & H.J Craig
Prewetting expansive clay to minimize heave of structures 375
G.A Jones & A.N Els
The influence of the mineralogy on the durability of Drakensberg basalts 383
J.L van Rooy
The impact rolling of a large housing site Boksburg 393
J.L van Rooy
The investigation, design and monitoring of concrete raft foundations on expansive soils: 401
A case study of preliminary performance
J.H Strydom & J.P Pellissier
8. General
The creation of job opportunities in geotechnical construction 411
H. Weber & J.E.S Boswell