11862 - LION PARK EIA
ANNEXURE B
GEOTECHNICAL INVESTIGATION
March 2010
Report No. 11862
Report to Winskor 135 (Pty) Ltd on a NHBRC Phase 1
Geotechnical Investigation for the Proposed Lion Park Eco-Estate
to be Situated on Portions 2 & 21 of the Farm Nooitgedacht 535JQ, Gauteng Province
Reference : 04-814/2
Date : 16 June 2005
MOORE SPENCE JONES (PTY) LTD
Consulting Geotechnical, Environmental & Civil Engineers
2nd Floor, Pharos House, 70 Buckingham Terrace, Westville, 3630
PO Box 1263, Wandsbeck, 3631
Tel : +027 031 2677202
Fax : +027 031 2665322
Report to Winskor 135 (Pty) Ltd on a NHBRC Phase 1 Geotechnical
Investigation for the Proposed Lion Park Eco-Estate to be Situated on
Portions 2 & 21 of the Farm Nooitgedacht 535-JQ, Gauteng Province
Reference : 04-814/2
Dated : 16 June 2005
TABLE OF CONTENTS
1.
INTRODUCTION AND TERMS OF REFERENCE .......................................................................................1
2.
PREVIOUS INVESTIGATIONS AND RESULTS ..........................................................................................1
2.1
Moore Spence Jones (Pty) Ltd: Report No 04-814/1 ....................................................................................1
2.2
Published Geological Map 2527 DD Broederstroom (1973).........................................................................2
2.3
Other Relevant Base Data ............................................................................................................................2
3.
INVESTIGATION METHOD AND RESULTS................................................................................................2
4.
SITE DESCRIPTION.....................................................................................................................................2
5.
FIELDWORK .................................................................................................................................................3
6.
SITE GEOLOGY............................................................................................................................................3
6.1
General Geology and Weathering of the Area ..............................................................................................3
6.2
Topsoil ...........................................................................................................................................................3
6.3
Alluvium .........................................................................................................................................................4
6.4
Hillwash .........................................................................................................................................................4
6.5
Pebble Marker ...............................................................................................................................................4
6.6
Residual Granite............................................................................................................................................4
6.7
Residual Diabase and Greenstone ...............................................................................................................4
6.8
Weathered Granite ........................................................................................................................................4
6.9
Weathered Diabase and Greenstone............................................................................................................5
7.
GROUNDWATER and SEEPAGE ................................................................................................................5
8.
LABORATORY TEST RESULTS ..................................................................................................................5
9.
GENERAL STABILITY OF THE SITE ...........................................................................................................7
10.
DEVELOPMENT RECOMMENDATIONS.....................................................................................................7
10.1
Proposed Development and Recommended Procedures............................................................................7
10.2
Trenchability and Rippability Assessment.....................................................................................................7
10.3
Drainage ........................................................................................................................................................8
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Contents
Page 1
Path : H:\MSJ Data\04\04-814\04-814-2.doc
10.3.1
Surface Drainage ..........................................................................................................................................8
10.3.2
Sub-Surface Drainage...................................................................................................................................8
10.4
Earthworks.....................................................................................................................................................9
10.5
Foundations...................................................................................................................................................9
10.5.1
Foundations on Collapsible Soils (Site Class C-C1) .....................................................................................9
10.5.2
Foundations on Composite Soils (Site Class C-H1-R) ...............................................................................10
10.5.3
Foundations on Shallow/Outcropping Rock (Site Class R).........................................................................10
10.5.4
Foundations on Expansive Alluvial Clay (Site Class H2)............................................................................10
10.5.5
Surface Beds ...............................................................................................................................................10
10.5.6
Summary of Founding Conditions ...............................................................................................................11
10.6
Material Classification and Usage ...............................................................................................................11
10.7
Recommended Subgrade Treatment..........................................................................................................12
10.8
Pipe Bedding ...............................................................................................................................................12
11.
CONCLUSIONS ..........................................................................................................................................12
Appendix A
Appendix B
:
:
Inspection Pit Profiles
Laboratory Test Results
Figures 1 and 2
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Contents
Page 2
Path : H:\MSJ Data\04\04-814\04-814-2.doc
Report to Winskor 135 (Pty) Ltd on a NHBRC Phase 1 Geotechnical
Investigation for the Proposed Lion Park Eco-Estate to be Situated on
Portions 2 & 21 of the Farm Nooitgedacht 535-JQ, Gauteng Province
Reference : 04-814/2
1.
Dated : 16 June 2005
INTRODUCTION AND TERMS OF REFERENCE
MSJ were instructed by Mr Greg Albertyn of Winskor 135 (Pty) Ltd to complete the above-mentioned
investigation in a letter of appointment dated 11 April 2005. The scope of works and costs are based on
the MSJ quotation dated 21 October 2004 and referenced 04-814.01.
The fieldwork was completed on 14 and 15 April 2005. The intention of this investigation is to supplement
existing geotechnical information recently collected on the site, and to provide specific foundation
recommendations based on the results of these previous investigations, together with the information
gained during this investigation.
The proposed development comprises residential units, together with a strong tourism component
including a hotel and conference centre, a predator theme park (including animal enclosures, viewing
decks and restaurants) and a retail component.
The purpose of this Phase 1 NHBRC geotechnical site investigation report is to provide the following
information:
•
•
•
•
•
Qualify and quantify the nature and engineering properties of the underlying soil and rock strata,
particularly for the proposed Eco-Estate.
Provide a topographic slope analysis based on the information available at the time of the
investigation (ie the 1:10 000 orthophoto).
Draw attention to pertinent ground water conditions, including the necessary flood line determinations
at significant drainage paths traversing the site.
Provide preliminary NHBRC site classifications reflecting the variable foundation conditions
encountered across the site.
Provide any other information and recommendations that may influence the development as a whole.
It is important to remember that further geotechnical investigations will be required during construction,
including a Phase 2 NHBRC (or construction completion report), which normally comprises the mapping
of open service trenches to confirm the preliminary NHBRC classification zones presented in this report.
Depending on the confidence of the information gleaned from Phase 1 and 2, more detailed confirmatory
investigations may be required at individual stand to satisfy NHBRC enrolment.
2.
PREVIOUS INVESTIGATIONS AND RESULTS
2.1
Moore Spence Jones (Pty) Ltd: Report No 04-814/1
This investigation comprised the reconnaissance investigations into existing geotechnical information,
together with the preliminary assessment of 47 inspection pits on the site.
The investigation revealed layers of hillwash, alluvium, a pebble marker and residual granitic soils.
Collapsible sands and potentially expansive soils were identified but allowable bearing capacities of 100
kPa were suggested at a depth of 1m below ground level. Shallow perched water tables and shallow to
outcropping bedrock in isolated areas were indicated.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 1
Path : H:\MSJ Data\04\04-814\04-814-2.doc
The site was zoned according to planning investigations for urban developments (Partridge et al, 1993)1.
The majority of the site was classed as 1A with isolated areas of 2A. Significant areas possibly
affected by a 1:50 year floodline and shallow perched water tables were also defined and
classified as 3B/3C/3D/3L with 2B/3C/2L on the western margin (according to the system devised
by Partridge, Wood and Brink, 1993).
This investigation was completed prior to the completion of laboratory testing and is considered
qualitative only and should only be used for development potential and to a lesser extent, preliminary
urban planning purposes.
2.2
Published Geological Map 2527 DD Broederstroom (1973)
The published map at a scale of 1:50 000 shows the site to be underlain by granite of the Halfway House
Granite Formation which has been intruded by a number of diabase dykes.
2.3
Other Relevant Base Data
The site survey plan was still outstanding at the time of this investigation. The following information was
accessed and consulted:
3.
•
1:10 000 orthophotographs (2527 DD 24 and 2627 BB 4), 2002.
•
1:500 000 hydrogeological map (2526 Johannesburg), DWAF, 1999.
•
1:250 000 geological map (2526 Rustenburg), Government Printer, 1986.
INVESTIGATION METHOD AND RESULTS
The present investigation was restricted to the excavation of 47 inspection pits using a Cat 416C TLB and
the surface mapping of rock outcrops. The in situ soil profile was recorded and representative samples
were collected for laboratory testing to determine the engineering properties.
The average refusal of the IP’s was 2,0m on friable, weathered granite. Soil types encountered include
topsoil, hillwash, pebble marker, alluvium and residual granite.
Water seepage was encountered in one inspection pit recorded at 1,5m.
A number of diabase dykes were encountered.
4.
SITE DESCRIPTION
The site is approximately 209 hectares in extent and is roughly trapezoidal in shape and comprises
portions 2 and 21 of the farm Nooitgedacht 535 JQ. The site is bound to the northwest by portion 20 and
approximately by the R114 road. Portion 4 is located on the southern boundary and Farmall Agricultural
Holdings to the east. The north-eastern boundary is Millgate Farm Agricultural Holdings (see Figure 1).
The majority of the site is comprised of portion 2, and portion 21 occurs on the northern boundary as a 7
hectare portion.
The western portion of the site is occupied by the Lion Park and the eastern portion comprises open veld.
There is evidence that peach orchards were once grown on a portion of the site.
The overall ground slope of the site is gentle to moderate at 2 to 5º. The average ground elevation ranges
from a maximum of 1470 metres above sea level in the south-western corner to a minimum of 1395
metres above sea level on the northern boundary, with an average slope of 2,7º or 1V:21H or 5%.
1
Partridge TC, Wood CK and Brink ABA (1993): Priorities for Urban Expansion within the PWV Metropolitan Region: The
Primacy of Geotechnical Constraints. South African Geographical Journal, Vol 75, pp 9-13.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 2
Path : H:\MSJ Data\04\04-814\04-814-2.doc
One significant non-perennial drainage path traverses the site flowing in a north-easterly direction
towards the Juskei River further to the east (see Figure 1) and has been dammed just inside the eastern
boundary to provide a watering hole.
At the time of the investigation, the majority of the site was covered with long veld grass, scattered trees
and a few gravel roads. Isolated granite and diabase rock outcrops (whale-backs) were encountered in
various places.
Evidence of material borrowing was noticed outside the northern boundary and adjacent to the R114
road.
The layout of the site is shown in Figure 1.
5.
FIELDWORK
The fieldwork was carried out on 14 and 15 April 2005 and comprised the excavation of 47 inspection pits
with a CAT 416C TLB machine. The inspection pits were advanced to final depths ranging from 0,75m to
3,0m, with an average depth of 2,0 metres to refusal of the TLB machine. Each inspection pit position
was coordinated using a hand-held Garmin etrex Summit GPS unit, utilising a map datum of WGS 84 and
the UTM/UPS position format.
The approximate position of the inspection pits is shown in Figure 1. They were logged and sampled
using generally accepted South African Geoterminology Guidelines (1990)2. The detailed profile logs are
given in Appendix A.
At the time of the fieldwork, the exact position and alignment of the north-western boundary was
not known with certainty, and it was therefore assumed that this boundary was coincident with
the R114 road. Consequently, subsequent to the acquisition of more accurate cadastral
information, it was found that 2 of the inspection pits (namely IP12 and 13) are located outside the
area.
6.
SITE GEOLOGY
6.1
General Geology and Weathering of the Area
According to the published 1:50 000 Broederstroom 2527DD geological sheet, the site is underlain at
depth by weathered granite of the Halfway House Granite Formation with intrusions of diabase dykes
trending in northeast-southwest and northwest-southeast directions.
The relationship between the mean annual precipitation (600 to 800mm) and the mean annual
temperature (17,5 to 20,0ºC) of the area suggests that “moderate decomposition” of the bedrock should
be expected (Fookes et al., 1971). Weinert’s “N” value is 2 and suggests that residual soils will be of
average depth, transported soils will be shallow, and pedocretes, where present, will be ferruginous.
The weathered rocks described above are overlain in part by a mantle of, topsoil, hillwash, alluvium,
pebble marker and residual soils.
6.2
Topsoil
The majority of the site is covered by a mantle of topsoil, which generally comprises dry, dark grey brown,
loose, silty sand with roots. The average thickness is 0,1m.
2
Geoterminology Workshop (1990) – Guidelines for Soil and Rock Logging
SAIEG-AEG-SAICE (Geotech Div) pp47
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 3
Path : H:\MSJ Data\04\04-814\04-814-2.doc
6.3
Alluvium
The alluvial layer is confined to the drainage path area and generally comprises stiff to very stiff, fissured
and shattered, potentially medium expansive silty clay. The depth of the layer extends to in excess of
2,4m (see Figure 1).
The estimated allowable bearing pressure of this layer is in the region 50 to 100 kPa but will be prone to
consolidation settlement and/or heave movements, in correspondence with fluctuating moisture levels.
6.4
Hillwash
The hillwash layer occurs more predominantly at the base of the higher laying areas (and was found to be
absent mostly in the northern half of the site) as transported sand with a negligible collapse potential
(although a pin-holed and voided structure was recorded). The layer consists of dry to moist, orange
brown to grey brown, loose to medium dense, silty sand with roots.
The layer extends to a maximum depth of 1,0m with and average depth of 0,5m.
6.5
Pebble Marker
The pebble marker can generally be considered as ubiquitous in the areas underlain by granite, but is
conspicuous in its absence in the diabase and alluvial areas.
The layer comprises slightly moist to moist, pale grey brown, loose to medium dense, silty sandy gravel of
quarts and roots and separates the upper transported soils from the lower residual granite soils. In
general the layer occurs from a depth of 0,3 to 0,5m.
The estimated allowable bearing capacity of this layer varies from 50 to 100+kPa.
6.6
Residual Granite
The residual granite was encountered in most of the inspection pits, except those underlain by alluvium or
diabase, and comprises slightly moist, red orange brown blotched, medium dense, reworked silty sand.
The layer becomes partially to well-cemented and partially to well-ferruginised in areas confined to the
topographic mid-slopes and on the up-slope of the diabase dykes. The layer is generally encountered
from 0,4 to 0,7m.
The estimated allowable bearing pressure of this layer is in excess of 100 kPa, depending on the degree
of cementation.
6.7
Residual Diabase and Greenstone
Nine of the inspection pits (IP 21 to 24, 27, 29, 30, 32 and 40) encountered a variety of materials that
have been interpreted as residual diabase or greenstone. The layer can range from a firm to stiff,
potentially medium expansive clayey silt to medium dense, ferruginised silty sand with ferricrete nodules.
The layer generally reaches an average depth of 1,5m and either underlain by dense boulders of diabase
or weathered diabase bedrock.
Although this layer can be medium expansive, the consistency suggests an allowable bearing capacity in
excess of 100 kPa.
6.8
Weathered Granite
The majority of inspection pits encountered weathered granite from an average depth of 1,4m and
comprises highly to moderately weathered, friable, relic-jointed, very soft rock granite.
The estimated allowable bearing pressure of this layer is in excess of 250 kPa.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 4
Path : H:\MSJ Data\04\04-814\04-814-2.doc
6.9
Weathered Diabase and Greenstone
Situated directly beneath the residual diabase or greenstone, the weathered diabase or greenstone
consisting of medium to highly weathered, jointed, green grey, very soft rock diabase or greenstone.
The estimated allowable bearing pressure of the weathered diabase and greenstone is in excess of 250
kPa.
7.
GROUNDWATER and SEEPAGE
Groundwater seepage was not encountered in any of the inspection pits except slight perched seepage
water at IP 45 and 46 at 1,5m depth. Subsurface attenuation layers such as shallow bedrock, cemented
layers (such as ferricrete) and clayey alluvial soils have been identified in isolated areas through out the
site and localised perched water levels should be expected in these areas during and immediately after
the wetter summer months.
The non-perennial drainage path traversing the site has been determined for the 1:50 year flood and the
results were insignificant due to the limited catchment area.
The 1:500 000 Hydrogeological map series of the Republic of South Africa (Johannesburg) showed the
bedrock to be classified as an inter-granular and fractured aquifer. The borehole yield class is good at
more than 2 litres/sec. No major groundwater abstraction has been indicated in the area (Barnard, 2000).
Local knowledge reveals that a number of private boreholes are in use on the farm.
The electrical conductivity averages 38 mS/m with a mean pH of 7,5. The mean annual precipitation of
600to 800mm and mean annual evaporation of 1600 to 1800mm suggests a water deficit environment.
The site is located within the Limpopo-Indian drainage Basin and the DWAF A21 sub-catchment drainage
area.
8.
LABORATORY TEST RESULTS
Six undisturbed and seventeen bulk soil samples were recovered from various inspection pits in the
alluvium (2 samples), hillwash (5 samples), pebble marker (1 sample), residual granite (3 samples),
ferruginised residual granite (1 sample), residual diabase (4 samples) and weathered granite (1 sample)
and weathered granite (1 sample). These were tested for the establishment of bulk earthworks and
foundation characteristics.
All samples were tested for foundation indicator and six undisturbed samples were tested for collapse
potential characteristics. The estimated collapse potential percentage, however, was measured as
negligible (0,01 to 0,24%) in the hillwash and residual granite. The Elastic Modulae of the hillwash
samples ranged from 2,5 to 9,6MPa with and average of 5,4MPa.
The PI of the samples is in the range of 0,7 to 26,0% with an average of 10,8%, the highest average
being measured in the alluvium and the lowest in the hillwash.
A summary of the foundation indicator and CBR/Mod test results for the tested soils is given in Table 1
below.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 5
Path : H:\MSJ Data\04\04-814\04-814-2.doc
Table 1
Summary of Combined Results of Particle Size Distribution Analysis and
Atterberg Limit Determinations, Compaction, and CBR Testing
Description
(m)
Particle Size (%)
Alluvium IP19(0,3-1,8)
Alluvium IP16 (0,8-2,4)
Hillwash IP4 (0,5)
Hillwash IP43 (0,5)
Hillwash IP42 (0,5)
Hillwash IP39 (0,5)
Hillwash IP34 (0,3)
Pebble Marker IP8 (0,1-0,7)
Fer res granite IP11(0,7-1,4)
Residual granite IP8 (2,3)
Residual granite IP6(0,3-1,8)
Residual granite IP(0,3-1,2)
Weath granite IP20(1,2-2,8)
Res diabase IP30(1,0-2,0)
Res diabase IP29(0,3-1,2)
Res diabase IP27(1,0)
Res diabaseIP21 (0,75)
-
Silt
& Clay
55,0
52,5
45,8
26,3
34,6
20,2
23,5
10,5
38,5
47,2
50,3
44,0
40,7
75,0
42,6
54,8
49,1
Liquid Limit
Plasticity Index
Linear Shrinkage
Sand
41,5
45,8
47,0
68,6
60,3
77,8
72,9
59,0
30,6
42,7
47,5
42,5
60,1
22,9
38,3
39,1
36,3
Atterberg Limit *
Gravel
3,4
1,6
7,1
5,1
5,1
2,0
3,6
30,5
30,9
10,1
2,2
13,5
9,2
3,0
19,1
6,2
14,6
OMC
MDD
GM
LL
42,8
40,5
32,2
19,0
30,4
19,4
15,1
21,5
43,7
31,8
38,7
38,1
32,8
48,0
34,1
40,8
35,0
*
LL
PI
LS
-
*
Estimated values using PI/GM relationship (after O Schnitter)
PI
19,1
19,8
14,6
5,3
11,0
0,9
0,7
0,8
13,2
8,2
12,2
16,0
6,2
26,0
9,5
10,3
10,4
LS
10,0
10,7
7,3
3,3
5,3
0,0
0,0
0,0
7,3
4,7
6,0
8,0
3,3
12,7
4,7
6,7
6,7
0,73
0,76
0,85
1,08
0,97
1,19
1,10
1,78
1,4
0,9
0,67
0,99
1,21
0,33
1,09
0,69
0,95
Modified
AASH
TO
MDD
OMC
(kg/m3)
(%)
2131
1949
7,0
10,4
CBR Values (%)
@ Compaction MDD (%)
93
95
98
100
10*
10*
13*
24*
18*
35*
32*
49
63
74
87
112
6
10
13
18
27
20*
14*
14*
26*
4*
22*
15*
19*
Swell
PRA
TRH14
90
Optimum Moisture Content
Modified Dry Density
Grading Modulus
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
GM
Page 6
Path : H:\MSJ Data\04\04-814\04-814-2.doc
Med
Med
Low
Low
Low
Low
Low
0,09
0,48
Low
Low
Low
Low
M-H
Low
Low
Low
A.7.6(9)
A.7.6(8)
A.6(5)
A.2.4
A.6(1)
A.2.4
A.2.4
A.1.b
A.7.5(2)
A.4(3)
A.6(5)
A.6(5)
A.2.4
A.7.6(16)
A.4(3)
A.7.5(5)
A.6(3)
G8
G8
G8
G7
G7
G6
G7
G4
G8
G7
G8
G8
G6
G9
G7
G8
G7
9.
GENERAL STABILITY OF THE SITE
No areas of potential ground instability were noted during the course of the investigation apart from the
influence of the localised non-perennial stream which occupies the central portion of the site. Sporadic
rock outcrop areas will require special attention in terms of inclusion into the proposed development. It is
considered that the remainder of the site is stable and suitable for development provided that the
recommendations given in this report are adhered to.
The alluvium contained within the drainage path comprises stiff clay of medium potential expansiveness
but will react to moderate foundation loadings (up to 3 storeys) with 30 to 45mm consolidation settlement.
The gentle nature of the ground slope (4 degrees) is such that slope instability would not be a problem in
bulk earthworks under the category of residential development on the site.
The site is underlain by potentially erodible residual granite and potentially compressible alluvial clays
with scattered rock outcrop distributed through out the site.
According to these geotechnical constraints in relation to the envisaged development, the site will require
attention to the erodability of the soil, difficulty of excavation within the rock outcrop areas and the
potential for consolidation settlements and poor drainage within the alluvial clay area.
10.
DEVELOPMENT RECOMMENDATIONS
10.1
Proposed Development and Recommended Procedures
It is understood that the proposed final development will comprise single and multi-storey residential type
structures, a hotel and conference centre, a predator theme park and a retail component, together with
roads and services.
In terms of the NHBRC Residential Site Class Designations together with the evaluation of the
engineering soil characteristics at the site, it is concluded that generally the site can be
designated as Site Class C-C1 over the majority site. Significant areas of Site Class H2 and
P(Marsh) are confined to the drainage path area. Areas of Site Class R seem to be associated with
the diabase dyke intrusions which have been classified as a combination of C-H1-R (see Figure 2).
It is the responsibility of the developer to submit copies of this report and any other required
geotechnical information, to the relevant authorities, particularly the NHBRC.
Final NHBRC site class designation for each residential stand or erf may require further investigations
including the mapping of open service trenches during the construction phase, or individual detailed
foundation investigations in areas lacking information.
10.2
Trenchability and Rippability Assessment
The excavatability characteristics have been estimated from the performance of the TLB used for the
investigation. From the results of the inspection pit logs, refusal of the TLB excavator occurred at an
average of 2,0m with a minimum of 0,75m and a maximum in excess of 3m.
Nine of the inspection pits recorded depths of less than 1,5m. Seven of these experienced refusal of the
TLB machine. This represented 15% of the total number of inspection pits put down on site. Table 2
below shows the summary of the refusal depths less than 1,5m:
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 7
Path : H:\MSJ Data\04\04-814\04-814-2.doc
Table 2
Summary of Refusal Depths Less Than 1,5m Depth
IP
No
11
Refusal depth
(m)
>1,4
Layer description
Ferruginised residual granite
12
14
>1,4
1,2
Ferruginised residual granite
Medium weathered granite
22
29
0,75
1,4
Dense boulders of diabase
Soft rock diabase
32
33
39
42
0,9
1,3
1,2
1,0
Medium weathered diabase
Medium weathered granite
Well cemented residual granite
Well cemented residual granite
Comment (SANS 1200D)
Soft excavation to 1,5m+. Adjacent to
rock outcrop
Soft excavation to 1,5m+
Hard excavation from 1,2m. Adjacent to
rock outcrop
Boulder/hard excavation from 0,75m
Partial refusal. Intermediate excavation
from 1,4m
Hard excavation from 0,9m
Partial refusal. Hard excavation from 0,9m
Intermediate excavation from 1,0m
Intermediate excavation from 1,2m
Trenching may be carried out with similar light earthmoving machinery as used in the investigation (i.e.
TLB) to the final depths shown in Figure 1. Below these depths it is possible that heavier ripping will be
required. Restricted excavations encountering localised outcrop of hard rock granite or diabase may
require the assistance of pneumatic tools or even blasting and will be restricted to the diabase dyke areas
and the topographic mid-slopes of the site (generally between elevations 1425 and 1455 masl).
In general soft excavation can be expected to an average depth of 2,0m depending on the location on
site. Heavy ripping and/or blasting may be required in Site Class R and C-H1-R (within the diabase
dykes) to achieve required service trench depths and level terraces. Limited boulder excavation should be
allowed for.
Bulk earthworks excavations will require normal earthmoving plant to reach the levels envisaged due to a
gentle to moderate ground slope over the remainder of the site.
10.3
Drainage
A most important factor in the promotion of a stable site is the control and removal of both surface and
ground water from the site. It is important that the design of the stormwater management system allow
for the drainage of accumulated surface water. Such water should be directed towards the natural
drainage lines such as streams and ditches on the margins of the site, or towards the existing drainage
path running through the centre of the site. Disposal of stormwater should in any case conform to the
local authority’s requirements.
10.3.1
Surface Drainage
Surface drainage of building platforms should be designed to direct water away from fill edges, to prevent
overtopping of the fill crest and erosion of the fill embankment slopes. Surface water on these platforms
should be directed to, and collected in, open lined drains or piped to the drainage line. It is important
that grassing or protection of fill embankments be carried out as soon as possible after
construction and in this site to also minimise ponding of the water to reduce slope instability and
piping as the residual granite sands are very permeable and highly erodible.
Run-off from building roofs should be piped from gutters, through downpipes, and discharged into the
stormwater reticulation system.
10.3.2
Sub-Surface Drainage
The need for subsoil drains will have to be re-assessed on site during development but the
evidence suggests that subsoil drainage may be required in areas of shallow or outcropping rock
(Site Class R and C-H1-R) and in areas of poor drainage (Site Class H2 and P(Marsh)-H2).
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 8
Path : H:\MSJ Data\04\04-814\04-814-2.doc
Service trenches should remain dry during construction and not require special pumping, except in areas
of shallow groundwater seepage (IP 45 and 46 in the eastern corner).
It is strongly recommended that the subsoil drains (if required) be designed according to the
specific filter criteria of the in situ soils to prevent piping of the material and subsequent rapid
erosion of material. Improved damp roofing will be required beneath the surface beds of floor slabs
especially in Site Class R and Site Class H2 and P(Marsh)-H2.
10.4
Earthworks
From the generally gentle to moderate sloping nature of the site it is anticipated that cuts and fills
will be of the order of less than 1 metre (depending on the footprint dimensions of the envisaged
structures). Any surplus material from the weathered granite and residual soil should be
stockpiled or used directly in fills or layerworks in other areas of the development. The clayey
alluvium should be carted to spoil or used in the lining of water features or any other required
landscape features.
A certain amount of sorting will be required during bulk earthworks operation to exclude the larger boulder
material in isolated areas on site. The majority of the shallow material encountered on the site qualifies as
G4 to G9.
It is recommended that all earthworks be carried out in accordance with SANS 1200 (latest version).
All vegetation should be cleared from the areas over which fills are to be built.
In general, it is recommended that cut slopes and fill embankments have a maximum slope of 1
vertical to 1,5 horizontal to ensure stability. The need for the subsoil drainage both beneath and in fills
if there are any will have to be assessed during the earthworks, taking into account the height and locality
of individual fills.
The fills should be placed in layers not exceeding 200mm loose thickness, and compacted to a minimum
of 93% Modified AASHTO maximum dry density at 2% wet of optimum moisture content. Boulders larger
than ²/3 of the layer thickness must not be included in the fill material.
Fills placed on the downslope side of building platforms will generally consist of the residual
granite or alluvial clay removed from the excavations of the terraces. Cuts deeper than 2m on
average will begin to encounter hard weathered granite.
Both during and after construction, the site should be well graded to permit water to drain away readily
and to prevent ponding of water anywhere on the ground surface. All terraces and earthworks in general
should be sloped to a gradient of not less than 1 vertical in 50 horizontal to prevent ingress of water into
the subsoils since these soils are significantly permeable. Surface drainage should be directed away
from the crests of fill embankments to prevent over-topping and erosion of fill slopes.
10.5
Foundations
The evaluation of the founding conditions has been carried out for the proposed residential structures. In
general, larger commercial or multi-storey structures will require specific design and recommendations.
10.5.1
Foundations on Collapsible Soils (Site Class C-C1)
The majority of the site is classified as Site Class C-C1, which implies a potential collapse settlement of
less than 5mm to a maximum of 10mm. A variety of foundation options can be considered, including the
following:
•
Modified normal: Reinforced strip footings with articulation joints at some internal and all external
doors. Light reinforcement in masonry. Site drainage and service/plumbing precautions. Foundation
pressures not to exceed 50 kPa.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 9
Path : H:\MSJ Data\04\04-814\04-814-2.doc
•
•
•
10.5.2
Compaction of insitu soils below footings: Remove insitu material below foundations to a depth
and width of 1,5 times the foundation width or to a competent horizon and replace with same material
compacted to 93% Mod AASHTO density at –1% to +2% OMC. Normal construction with lightly
reinforced strip foundations and light reinforcement in masonry.
Deep strip foundations: Normal construction with drainage requirements. Founding on a competent
horizon below the hillwash onto the pebble marker or residual granite layer. This option is
recommended.
Soil raft: Remove insitu material to 1,0m beyond perimeter of building to a depth of 1,5 times the
widest foundation or to a competent horizon and replace with same material compacted to 93% Mod
AASHTO density at –1% to +2% OMC. Normal construction with lightly reinforced strip footings and
light reinforcement in masonry.
Foundations on Composite Soils (Site Class C-H1-R)
The diabase dyke areas will be governed by the H1 classification (due to the medium expansive residual
silt) and provided this classification is confirmed on site during the NHBRC Phase 2 investigation, the
following foundation options can be considered:
•
•
Modified normal: Lightly reinforced strip footings. Articulation joints at all internal/external doors and
openings. Light reinforcement in masonry. Site drainage and plumbing/service precautions.
Soil raft: Remove all or part of expansive horizon to 1,0m beyond the perimeter of the structure and
replace with inert backfill compacted to 93% Mod AASHTO density at –1% to +2% OMC. Normal
construction with lightly reinforced strip footings and light reinforcement in masonry. Site drainage
and service/plumbing precautions.
Alternatively, the localised and linear nature of the diabase areas could be included into the urban design
layout as either open space or access road, especially in view of the fact that the subsoil conditions are
characterised by high variability.
10.5.3
Foundations on Shallow/Outcropping Rock (Site Class R)
Shallow or outcropping bedrock areas have been assigned a Site Class R in five separate significant
areas on the site. Normal strip foundations or slab-on-the-ground foundations can be employed in this
area although an allowance for hard excavation or even blasting should be allowed, especially for the
installation of services (see Figure 2). This procedure is not considered cost effective and thus these
areas should be reserved as open space/parkland.
10.5.4
Foundations on Expansive Alluvial Clay (Site Class H2)
This area is confined to the drainage path and the adjacent area to the north-west (see Figure 2).
Expected ground movements of between 15 and 30mm will require the consideration of the following:
•
•
•
•
10.5.5
Stiffened or cellular raft: Stiffened or cellular raft with articulation joints or solid, lightly reinforced
masonry. Site drainage and plumbing/service precautions.
Piled construction: Piled foundations with suspended floor slabs with or without ground beams. Site
drainage and plumbing/service precautions.
Split construction: Combination of reinforced brickwork/blockwork and full movement joints.
Suspended floor slabs or fabric reinforcement in ground slabs acting independently from the
structure.
Soil raft: As per H1 above (in sub-section 10.5.2).
Surface Beds
It is recommended that the subgrade beneath surface beds or floor slabs be ripped to a minimum depth
of 150 mm and compacted to 93% Mod AASHTO density. It is recommended that an approved damp
proof membrane be used beneath the floor slabs.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 10
Path : H:\MSJ Data\04\04-814\04-814-2.doc
10.5.6
Summary of Founding Conditions
Table 3 below shows the variation in estimated allowable bearing capacity (EABC) with each layer:
Table 3
Estimated Allowable Bearing Capacities (EABC)
Soil Layer
Alluvium
Hillwash
Pebble marker
Residual granite
Residual diabase
Weathered
diabase/greenstone
Weathered Granite
10.6
Depth (m-m)
0 – 3,2+
0 – 0,4
0,3-0,5
0,4 – 1,8
0,4-1,1
1,1+
EABC (kPa)
50 to 100
50 to 100
50
100+
100+
250+
0,2 – 1,0+
250+
Comments
Highly compressible and expansive layer
Collapse potential
Collapse potential
Suitable founding layer
Can be expansive in places
Excellent founding layer
Excellent founding layer
Material Classification and Usage
The materials encountered on site have been classified in terms of their suitability for use in earthworks
and road construction on the basis of field observations and laboratory testing. The classification is
summarised in Table 4 below:
Table 4
Classification and Recommended Use of Materials
Material
Description
Hillwash
Alluvium
Pebble marker
Residual
diabase
Residual
Granite
Weathered
Granite
Classification and Assessment of Materials
Dry to slightly moist to moist, dark brown, loose,
silty sand with abundant course gravel cobbles of
quartz.
PI = 0,7 to 14,6%
PRA = A.2.4 to A.6(3)
Anticipate material quality G6 to G8
Slightly moist to moist, dark grey brown, medium
dense intact clayey silty sand to stiff to very stiff
silty clay to clayey silt.
PI =19,5%
PRA = A.7.6(9)
Anticipate material quality to G8.
Loose to medium dense, silty sandy gravel.
PI = 0,8%
PRA =A.1.b
Anticipate material quality G4
Highly variable conditions ranging from medium
expansive silt to densely packed boulders.
PI = 9,5 to 26,0%
PRA = A.4(3) to A.7.6 (16)
Anticipate material quality G7 to G9
Dry to slightly moist, red orange brown speckled
black orange, medium dense to dense, intact,
partially ferruginised, silty sand becoming highly
to completely weathered granite.
PI = 8,2 to 16,0%
PRA = A. 4(3) to A6(5)
Anticipate material quality G7 to G8.
Highly to medium weathered, closely spaced,
fractured and jointed, leached and friable, buff,
medium hard to soft rock granite.
PI = 6,2%
PRA = A.2.4
Anticipate material quality to G6.
Recommended Use and Other Applicable
Comments
Excellent to good subgrade material. Rip to
150mm and re-compact to 93% Mod AASHTO
density at +2% of OMC.
Neat CBR @ 93% = 13 to 35% (ave = 24%)
Poor in situ subgrade material. Over-excavate
min 500mm below top of subgrade layer and
replace with G5 material compacted to
93%Mod AASHTO dry density at +2% of
OMC.
Neat CBR @ 93% Mod AASHTO = 10%.
Excellent in situ subgrade material and
qualifies as basecourse material. This material
should be sourced and borrowed for use in the
development.
Expansive silt and boulders should be overexcavated to 500mm and replaced with
approved compacted backfill.
Neat CBR @ 93% = 4 to 22%.
Good to fair subgrade material. Neat CBR =
14 to 20% @ 93% Mod AASHTO density.
Possibly too deep to be encountered in
earthworks operations.
Excellent subgrade material. Neat CBR = 14%
@ 93% Mod AASHTO density.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 11
Path : H:\MSJ Data\04\04-814\04-814-2.doc
10.7
Recommended Subgrade Treatment
The in situ materials are generally suitable for use as a subgrade material in the construction of roads in
Site Class C-C1 areas. Where roads are constructed in this area, the subgrade should be ripped to a
minimum depth of 150mm below top of subgrade and compacted to a minimum of 93% Mod AASHTO dry
density.
In the poorer subgrade areas crossing Site Class H1 and H2, it is suggested that a minimum overexcavation of 500mm be effected to allow the placement of compacted rock fill or similar material, if the
construction of roads in this area is unavoidable.
The areas of rock outcrop (Site Class R in Figure 2) will require over-excavation to a minimum of 500mm
and replacement with compacted G5 quality material on site. Preferably, this area should be avoided
in terms of construction development if possible.
The test results of the residual granite and weathered granite available on site show a G7 and G6 quality
material respectively. The weathered granite therefore qualifies as a subbase material and should
be stockpiled whenever encountered in excavation. The pebble marker also qualifies as a
basecourse material and should be exploited and managed accordingly.
10.8
Pipe Bedding
None of the in situ materials occurring on site meet the strict bedding specifications of SABS 1200LB and
importation of this material should be allowed for. However, if the pipe bedding stiffness (E’) value of
7,5MPa is adopted, then the more granular materials occurring on site (pebble marker and coarse
weathered granite) may be considered.
11.
CONCLUSIONS
This report contains the results of a Phase 1 NHBRC geotechnical investigation carried out on portion 2
and 21 of the farm Nooitgedacht 535-JQ, Gauteng Province. The proposed development comprises a
substantial residential component, together with a hotel and conference centre, predator park,
commercial section, roads and services.
It is considered that conditions prevailing at the site are generally favourable for the structural
elements of the development, provided the recommendations given in this report are adhered to.
The foundation and development recommendations are applicable to the residential sections and
thus more specific attention will be required for more substantial structures.
The subsoil conditions encountered over the site generally comprise loose potentially collapsible hillwash
and pebble marker, residual granite and diabase/greenstone, alluvial soils underlain by weathered granite
or diabase/greenstone rock.
Recommendations for earthworks and drainage to promote the stable development are given especially
in areas of close to the drainage paths.
The majority of the site can be designated as Site Class C-C1 and modified foundation
construction will be required which may include modified normal construction, compaction below
footings, deeper founding levels or soil rafts. The option of deep strip footings is recommended.
A significant alluvial area in the central portion of the site is designated as Site Class H2 and
structures should be properly founded on stiffened or cellular rafts, piles, split construction or
soil rafts. Shallow and outcropping bedrock is also evident over restricted and localised areas
and have been zoned Site Class R. Normal strip or slab-on-the-ground foundations can be
considered here but hard excavation (with blasting) will be required to achieve level building
platforms and service trench installations.
It is the responsibility of the Developer to provide copies of this report to the relevant local authorities,
especially the NHBRC, to facilitate enrolment.
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 12
Path : H:\MSJ Data\04\04-814\04-814-2.doc
The information contained in this report can be used for urban planning, construction costing and
preliminary architectural detailing. However, a Phase 2 NHBRC investigation, comprising either
service trench mapping or individual foundation investigations for specific stands, may be
required for final NHBRC enrolment.
Finally, the ground conditions described in this report refer specifically to those encountered in the
exposure profiles, previous investigations, adjacent trenches and inspection pits put down on site. It is
therefore quite possible that conditions at variance with those discussed above can be
encountered elsewhere on the site.
It is therefore important that Moore Spence Jones (Pty) Ltd carry out periodic inspections of the open
excavations. Any change from the anticipated ground conditions could then be taken into account to
avoid unnecessary expense. In this regard it is important that the construction phase of the project be
treated as an augmentation of the geotechnical investigation.
MOORE SPENCE JONES (PTY) LTD
Consulting Geotechnical, Environmental & Civil Engineers
2nd Floor, Pharos House, 70 Buckingham Terrace, Westville, 3630
PO Box 1263, Wandsbeck, 3631
Tel : +027 031 2677202
Fax : +027 031 2665322
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 13
Path : H:\MSJ Data\04\04-814\04-814-2.doc
FIGURES
Proposed Lion Park Eco-Estate on Farm Nooitgedacht
MOORE SPENCE JONES
Page 1
Path : H:\MSJ Data\04\04-814\04-814-2.doc
-94Y
142
5
IP 13
1.0
(2.1)
0.6
(0.9)
0
147
Approximate position of Inspection Pit showing depth to bedrock
and depth to refusal in metres below existing ground level.
IP 31
1.0
(1.8)
25.1
9m
AVE
NUE
ARD
1.8
(2.5)
e
wid
4m
56
Y - 95 000
A
76
64
/1
96
RI
9
ET
DE
VA
ED
LL
NO
EI
RO
52
4/
AD
19
72
18
s2
,8
9m
4,
0
1425
X + 2 877 000
SE
R
VI
TU
DE
SG
1.0+
(1.0)
42
43
NO
IP 42
FARMALL AGRICULTURAL HOLDINGS
IP 41
58
0.8
(2.4)
1.2
(1.4)
59
14
45
35
30
14
Y - 94 000
14
14
40
IP 28
X + 2 877 500
RTIO
PO
N
60
1.8
(3.0)
JA
110
CK
SO
N
RO
REMAINDER OF PORTION 4
AD
15
,7
4
m
Site Plan showing approximate positions of :
Rock Outcrop
1.6
(2.2)
1425
1.8
(2.5)
2.3
(2.4)
IP 29
Granite
Borrow Pit
IP 43
GRANITE
14
Y - 93 000
X + 2 877 500
IP 34
50
55
1460
2.0
(2.2)
14
Alluvium
Diabase Dyke
IP 30
5
146
REMAINDER OF PORTION 4
ZANDSPRUIT NO 191 - IQ
20
57
1.4
(2.4)
GRANITE
14
1.6
(2.2)
IP 44
IP 47
IP 32
15
7
1.8
(2.5)
1425
Y - 93 000
Y - 92 500
Y - 92 500
1.3
(2.1)
NUE
25.19
m
IP 45
1.6
(1.7)
0.9
(1.3)
AVE
14
IP 46
2.0
(2.1)
IP 40
IP 33
E
AS
AB
DI
2.3+
(2.3)
2.3+
(2.3)
IP 3
1.2+
(1.2)
10
IP 35
PORTION 2 OF NIETGEDACHT NO 535 - JQ
SE
IP 1
140
0
2.3+
(2.3)
IP 39
1.2
(2.8)
DIABA
1.2
(2.2)
IP 20
KIND
R ED
GRANITE
1.8
(2.6)
2.5+
(2.5)
14
IP 38
SE
BA
DIA
E
AS
IP 2
KEY:
IP 1
IP 8
2.6+
(2.6)
IP 5
1.4
(1.8)
IP 19
1.7+
(1.7)
05
8
IP 37
ALLUVIUM
IP 21
14
9
1.6
(2.2)
2.0+
(2.0)
0.75+
(0.75)
00
IP 36
IP 18
IP 22
1.7
(2.0)
IP 7
140
5
1.75+
(1.75)
(1.75)
R EM
AIN
DE
PO
RTIO R OF
N3
6
X + 2 877 000
2.4+
(2.4)
X + 2 876 000
10
14
1.0
(2.1)
IP 16
1.75+
(1.75)
IP26
IP
2.0+
(2.0)
22
IP 27
25
GRANITE
1.75+
GRANITE
1.0
(2.1)
IP 17
IP 24
AB
DI
IP 4
141
0
E
AS
AB
DI
2.1+
(2.1)
1.8+
(1.8)
1.8
(2.6)
21
1.4+
(1.4)
IP 10
IP 9
IP 6
IP 15
IP 23
GRANITE
MILLGATE FARM AGRICULTURAL HOLDINGS
PORTION 21
NIETGEDACHT NO 535 - JQ
141
5
1.4+
(1.4)
Y - 95 000
GRANITE
IP 11
X + 2 876 000
20
142
0
SE
BA
DIA
1.0
(1.2)
NORTH
IP 14
HOW
1.4+
(1.4)
Y - 94 000
IP 12
DATE
WINSKOR (PTY) LTD
20/05/2005
DRAWN
a.) Inspection Pits.
b.) Inferred Geology
Geotechnical Investigation for
Lion Park Eco-Estate, Phase 1
A.S.
CHECK
A.M.W.
REFERENCE No.
04 - 814
M O O R E S P E N C E J O N ES
Scale 1 : 10 000 (On A3 Original)
CONSULTING GEOTECHNICAL, CIVIL & ENVIRONMENTAL ENGINEERS
CONSULTING GEOLOGISTS & SCIENTISTS
FIGURE No.
REV.
1
04-814/DRAWINGS/GEO.DRG
-94Y
Foundation design, building procedures and precautionary
measures for single storey residential structures founded on
expansive soil horizons. (NHBRC 1999)
Articulation joints at all internal / external doors and
openings
•
Light reinforcement in masonry
-R
•
Site drainage and plumbing / service precautions
•
Combination of reinforced masonry and full
movement joints
•
Suspended floors or fabric reinforced ground slabs
acting independently from the building
•
Site drainage and plumbing / service precautions
•
As for H1
C - C1
ARD
Foundation bearing pressure not exceeded 50kPa
14
NOTE : FLOODLINE DETERMINED BY C. BROOKER PR. ENG.
Compaction of
insitu soils below
individual footings
•
Remove insitu material below foundations to a depth and
width of 1.5 times the foundation width or to a competent
horizon and replace with material compacted to 93% MOD
AASHTO density at -1% to +2% of optimum moisture content.
•
Normal construction with lightly reinforced strip
foundations and light reinforcement in masonry
e
wid
40
Y - 95 000
A
76
64
/1
96
RI
9
ET
DE
VA
ED
LL
NO
EI
RO
52
4/
AD
19
72
18
s2
,8
9m
4,
0
NO
60
X + 2 877 500
14
Site drainage and plumbing / service precautions
•
SG
50
45
14
Light reinforcement in masonry
•
4m
1425
5
14
X + 2 877 500
14
•
59
55
Articulation joints at some internal and all external doors
RTIO
PO
N1
10
JA
CK
SO
N
RO
REMAINDER OF PORTION 4
Site Plan showing NHBRC Classifications
AD
15
,7
4
m
DATE
WINSKOR (PTY) LTD
20/05/2005
DRAWN
Deep strip
foundations
Soil raft
•
Normal construction with drainage precautions.
Founding on a competent horizon below the problem
horizon
•
Remove insitu material to 1.0m beyond perimeter of
building to a depth of 1.5 times the widest foundation or
to a competent horizon and replace with material compacted
to 93% MOD AASHTO density at -1% to +2% of optimum
moisture content.
•
Normal construction with lightly reinforced strip
footings and light reinforcement in masonry
X + 2 877 000
58
R
14
Reinforced strip footings
•
1460
•
146
Good site drainage
56
VI
TU
DE
0
147
C - C1
Y - 93 000
•
1425
SE
R
Y - 92 500
Y - 92 500
R
Modified normal
Normal construction (strip footing or slab-on-the-ground)
foundation
42
-R
5 - 10
7
FARMALL AGRICULTURAL HOLDINGS
H1
C1
•
C - C1
C-
Normal
C - C1
1-H
C - H1 - R
<5
20
1425
C
-R
C
14
57
FOUNDATION DESIGN AND BUILDING PROCEDURES
(Expected damage limited to Category 1)
REMAINDER OF PORTION 4
ZANDSPRUIT NO 191 - IQ
15
43
H1
CONSTRUCTION
TYPE
NUE
25.19
m
C - C1
PORTION 2 OF NIETGEDACHT NO 535 - JQ
C - C1
Foundation design, building procedures and precautionary
measures for single storey residential structures founded on
expansive soil horizons. (NHBRC 1999)
14
C - C1
C - C1
.0
46
R
X + 2 877 000
ESTIMATED
TOTAL
SETTLEMENT
(mm)
H2
C-
R EM
AIN
DE
PO
RTIO R OF
N3
6
SITE
CLASS
AVE
R
C - C1
10
2
Piled foundations with suspended floor slabs with or
without ground beams
14
-H
•
05
8
P(
FL
O
O
D)
Site drainage and plumbing service precautions
-R
Soil raft
•
14
9
KIND
R ED
H1
Split construction
Stiffened or cellular raft or articulated lightly
reinforced masonry
C-
Piled construction
C - C1
•
00
H2
30
Stiffened or cellular
raft
Site drainage and plumbing / service precautions
X + 2 876 000
10
14
Normal construction with lightly reinforced strip footings
and light reinforcement in masonry if residual movements
are <7.5mm, or construction type appropriate to residual
movements
Y - 93 000
15 - 30
140
0
H2
22
C - H1 - R
•
140
5
•
(7,7495 ha)
R
Remove all or necessary parts of expansive horizon to
1.0m beyond the perimeter of the building and replace
with inert backfill compacted to 93% MOD AASHTO
density at -1% to +2% of optimum moisture content.
141
0
•
Site drainage and plumbing / service precautions
21
141
5
Soil raft
MILLGATE FARM AGRICULTURAL HOLDINGS
C - C1
PORTION 21
NIETGEDACHT NO 535 - JQ
X + 2 876 000
•
20
R
Y - 95 000
•
NORTH
Lightly reinforced strip footings
25.1
9m
•
AVE
NUE
Site drainage and service / plumbing precautions
recommended
HOW
•
Y - 94 000
Normal construction (strip footing or slab-on-the-ground)
foundation
142
0
Modified normal
•
35
Normal
H1
7.5 - 15
FOUNDATION DESIGN AND BUILDING PROCEDURES
(Expected damage limited to Category 1)
C-
H1
< 7.5
CONSTRUCTION
TYPE
142
5
H/R
ESTIMATED
TOTAL
HEAVE
(mm)
Y - 94 000
SITE
CLASS
Geotechnical Investigation for
Lion Park Eco-Estate, Phase 1
A.S.
CHECK
A.M.W.
REFERENCE No.
04 - 814
M O O R E S P E N C E J O N ES
Scale 1 : 10 000 (On A3 Original)
CONSULTING GEOTECHNICAL, CIVIL & ENVIRONMENTAL ENGINEERS
CONSULTING GEOLOGISTS & SCIENTISTS
FIGURE No.
REV.
2
04-814/DRAWINGS/NHBRC.DRG