GEOTECHNICAL PHASE 1

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1 GEOTECHNICAL PHASE 1 FOR PROPOSED SKUKUZA SAFARI LODGE FOR KRUGER NATIONAL PARK MPUMALANGA PROVINCE SEPTEMBER 2014 Report No: G Issue 2 Prepared by: Conic North Consulting Engineers PO Box Bendor 0699 Tel no: Fax no: conic@webmail.co.za

2 CONTENTS 1. EXECUTIVE SUMMARY ENGINEERING PARAMETERS NHBRC CLASSIFICATION INTRODUCTION METHOD OF INVESTIGATION SITE DESCRIPTION LOCATION TOPOGRAPHY SURFACE HYDROLOGY FIELD WORK GEOLOGICAL SETTINGS TEST HOLES GENERALIZED SOIL PROFILES GROUND WATER MECHANICAL TRANSPORTATION SLOPES EXCAVATION SIDEWALL STABILITY SURFACE WATER DOLOMITIC BEDROCK TEST RESULTS FOUNDATION INDICATOR TESTS ENGINEERING CHARACTERISTICS GENERAL EXCAVATABILITY ENVIRONMENTAL IMPACT CONSIDERATIONS FOUNDATION DESIGN AND CONSTRUCTION CONCLUSION REPORT PROVISIONS REFERENCES ANNEXURE ANNEXURE A: LOCALITY ANNEXURE B: SOIL PROFILES ANNEXURE C: TEST RESULTS Skukuza Safari Lodge September 2014 Report No: G

3 1. EXECUTIVE SUMMARY Conic North was appointed by Endecon Ubuntu to do a Geotechnical phase 1 Investigation and report for the proposed Skukuza Safari Lodge in the Kruger National Park. The site is approximately m² with existing buildings. The investigation consisted of a site walk over and inspections of excavated test pits to determine the insitu soil profiles. According to the Geological Map of South Africa, 2430 PELGRIM S REST, 1985, Scale 1: the site is underlain by Quartz- microline-plagioclase-biotite migmatite and Gneiss with abundant mafic and ultramafic xenoliths of the Nelspruit Suite. Groundwater was encountered in test pit 1 only. 1.1 Engineering Parameters Perched groundwater table in high precipitation years, Excavations could be classified as medium, Possible collapsing of excavation side walls of deep excavations, The site is not underlain by dolomitic rocks, Due to the high sand content of the insitu material storm-water drainage must be planned carefully to avoid scouring especially in areas were the insitu soil is disturbed The proposed development area is not influenced by the 1: 100 flood line area. For structures more than 3 storeys a detailed geotechnical investigation with preferably core drilling should be done. 1.2 NHBRC classification NHBRC Site Class H1, S & C. Maximum bearing capacity as Indicated in paragraph 7.4 Constraint: Specialized Foundations to be designed by competent Engineer. Skukuza Safari Lodge September 2014 Report No: G

4 2. INTRODUCTION Conic North was appointed by Endecon Ubuntu to do a geotechnical investigation report for the proposed Skukuza Safari Lodge in the Kruger National Park. The site is approximately m² with existing buildings. The proposed new buildings would mainly consist of single and double storey structures. This report deals with the evaluation of the geotechnical character of the soil materials underlying the subject property for the purpose of foundation design and services installation. The report focuses mainly on the following aspects: - Site description. - Surface Hydrology - Method of investigation. - Fieldwork. - Engineering Characteristics. Skukuza Safari Lodge September 2014 Report No: G

5 3. METHOD OF INVESTIGATION The site visit included a site walkover and investigation of test pits excavated by TLB Excavator up to refusal to determine the soil profiles. Four test pits could be excavated around the existing buildings. All test pits and excavations were co-ordinated and photographed. The soil profiles were recorded as recommended by SAIEG. The test pit profiles are included in Annexure B. Disturbed soil monsters of all soil types were submitted for laboratory foundation indicator testing. The disturbed samples were conducted by Messrs. Letaba Lab. Polokwane Skukuza Safari Lodge September 2014 Report No: G

6 4. SITE DESCRIPTION 4.1 LOCATION The site is located in Skukuza Camp in the Kruger Park. The exact location in camp is west of the existing conference centre on a portion of land where the existing buildings will be demolished. The co-ordinates of the site are S and E See Annexure A for the Locality map. 4.2 TOPOGRAPHY The topography can be characterized as moderately flat. The average slope is approximately 1.8% north. Farm Name Maximum Slope Mean average Level Approximate area of village Flood line % 279m m² No DRAINAGE The study area is drained entirely by means of surface flow into the existing road network, which drains to the Sabie River approximately 190m north of the site CLIMATE The study area is located in the summer rain fall zone of the Republic of South Africa. The mean annual precipitation of the study area is approximately 805mm according to the Champagne weather station. The maximum temperature seldom rises above 40 degrees Celsius and the minimum seldom reach -1 degree Celsius. The mean daily temperatures averaging from 17 to 28 ºC. Skukuza Safari Lodge September 2014 Report No: G

7 4.2.5 VEGETATION The existing buildings were developed within the natural bush. The vegetation mainly consists mainly of Acacia-, Combretum- and Marula trees and grass. Skukuza Safari Lodge September 2014 Report No: G

8 5. SURFACE HYDROLOGY The study area falls within the Quaternary catchment area B6C. Surface water mainly flows overland to small streams that drain to the Sabie River. The mean annual runoff is mm over the total area. The mean annual evaporation is 1600mm 1700mm according to the Surface Water Resources of SA Skukuza Safari Lodge September 2014 Report No: G

9 6. FIELD WORK 6.1 GEOLOGICAL SETTINGS According to the Geological Map of South Africa, 2430 PELGRIM S REST, 1985, Scale 1: the site is underlain by Quartz- microline-plagioclase-biotite migmatite and Gneiss with abundant mafic and ultramafic xenoliths of the Nelspruit Suite. Site Skukuza Safari Lodge September 2014 Report No: G

10 6.2 TEST HOLES Four test holes excavated by TLB excavator to refusal were profiled. 6.3 GENERALIZED SOIL PROFILES Description Depth Bearing Capacity Comments Dry, brown, fine grained, silty, clayey loose sand with roots. 0mm 350mm <20kPa Transported Dry, brown medium grained, ferricrete 350mm - 950mm kPa Ferricrete Dry, grey clayey sand 950mm 1300mm 150kPa+ Calcrete 6.4 GROUND WATER TP1 encountered a small amount of syphoning ground water at a level of 2.2m below natural ground level. None of the other test pits encountered ground water. 6.5 MECHANICAL TRANSPORTATION No test pits revealed a distinctive pebble marker. 6.6 SLOPES The study area could be classified Class 1 slopes, which is < 2. The area is suitable for development and construction. Skukuza Safari Lodge September 2014 Report No: G

11 6.7 EXCAVATION SIDEWALL STABILITY Test pit sidewalls of up to 1.5m in general were stable. Due to sand content of material all excavation sidewalls > 1.5m that will be open for more than 24hrs is recommended to be shored. 6.8 SURFACE WATER Surface water of study area could be channelled on the road network with outlets at the natural low points to drain to the Sabie River north of the site. 6.9 DOLOMITIC BEDROCK The site is not underlain by dolomitic rock and as far as could be determined no mining activities close to the study area. Skukuza Safari Lodge September 2014 Report No: G

12 6.10 TEST RESULTS FOUNDATION INDICATOR TESTS No Depth Description Clay % P3161/7 TP1 P3161/8 TP1 600mm 1450mm Silty Clayey Sand Silty Clayey Sand Silt % Sand % Gravel % LL PI LS GM Double Hydro % Heave Potential Low Low P3161/9 TP2 380mm Clayey Gravel Low P3161/10 TP2 750mm Sandy Gravel SP Low P3161/11 TP3 500mm Sandy gravel NP Low P3161/12 TP4 100mm Silty Sand SP Low P3161/13 TP4 500mm Clayey Sand Low P3161/14 TP4 1150mm Clayey Sand Low COMMENTS < 10 mm Settlement & < 7.5mm heave potential & 5mm 10mm collapsible Settlement < 10 mm Settlement & < 7.5mm heave potential & 5mm 10mm collapsible Settlement < 10 mm Settlement & < 7.5mm heave potential & < 5mm collapsible Settlement < 10 mm Settlement & < 5mm collapsible Settlement < 10 mm Settlement & < 5mm collapsible Settlement < 10 mm Settlement & < 5mm collapsible Settlement < 10 mm Settlement & 7.5mm 15mm heave potential < 10 mm Settlement & 7.5mm 15mm heave potential The heave potential is according to the Van der Merwe chart. Skukuza Safari Lodge September 2014 Report No: G

13 7. ENGINEERING CHARACTERISTICS 7.1 GENERAL It is assumed that the buildings will consist of maximum double storey structures. 7.2 EXCAVATABILITY The material is pickable and foundation trenches can be excavated by TLB excavator. Test pit excavations indicate soft material up to 1.0m. Excavations for services installation up to 2.0m would be possible by TLB excavator. The majority of the site earthworks classification regarding services could be classified as soft to medium excavation. Shoring of trenches > 1.5m that will be open for more than 24hrs are recommended. Earthworks specification as prescribed by the Engineer (SANS 1200) should apply. 7.3 ENVIRONMENTAL IMPACT CONSIDERATIONS The sandy gravel material is permeable that may lead to contamination of groundwater. 7.4 FOUNDATION DESIGN AND CONSTRUCTION The test results indicate that the top soil mainly consists of silty clayey sand. The bearing capacity is low with possible heave and collapsible potential. No foundations should be founded at a level of < 450mm. Some of the areas within the existing erven were stripped of top soil and others top soil were imported for gardening purposes. Zone 1: Layer 2 in general consists of brownish sandy gravel. The material has a potential settlement of <10mm and a potential collapsible settlement of < 5mm, due to the high sand content. The bearing capacity for levels between 400mm to 700mm below natural ground level varies from 60Kpa 150Kpa and increase with depth. Zone 2: Layer 2 in general consists of brownish clayey sand and has a settlement potential of < 10mm and heave potential of 7.5mm 15mm. The bearing capacity for levels between 700mm to 1.8m varies from 60Kpa to 100Kpa and increase with depth. Skukuza Safari Lodge September 2014 Report No: G

14 Zone 1: Layer 3 in general consists of brownish sandy gravel and greyish calcrete, which varies from 450mm to 700mm below natural ground level. The refusal level is on calcrete. The bearing capacity for layer 3 at 700mm is approximately 150Kpa and estimated 350Kpa to +400Kpa at refusal level. Any structure that may consist of more than 3 storeys would require a detailed geotechnical investigation to determine calcrete layer thickness. The material has a potential settlement of <10mm and a potential collapsible settlement of < 5mm. Zone 2: Layer 3 in general consists of brownish sandy gravel and greyish calcrete, which varies from 800mm to 2200mm below natural ground level. The refusal level is on calcrete. The bearing capacity for layer 3 at 1200mm is approximately 150Kpa and estimated 350Kpa to +400Kpa at refusal level. Any structure that may consist of more than 3 storeys would require a detailed geotechnical investigation to determine calcrete layer thickness. The material has a settlement potential of < 10mm and heave potential of 7.5mm 15mm. NHBRC site Classification Section NHBRC classifica tion Estimated collapse/ heave Construction Type Foundation recommendations Zone 1 & 2 < 450mm depth H & C1 < 7.5mm & 5mm 10mm No foundations Zone 1 Depth > 450mm S & C < 10mm & < 5mm Normal Normal strip footings Good site drainage Zone 2 Depth > 450mm H1 7.5mm 15mm Modified Normal Soil Raft Reinforced strip footings Articulation joints at some internal and all external doors. Light Reinforcement in masonry Good site drainage and service/plumbing precautions Foundation pressure not exceeding 80 kpa Or Remove insitu material to 1m beyond perimeter of building to a depth of 1.5 times the foundation width or to competent horizon and replace with G6 material compacted to 93% MOD AASHTO. Normal construction with lightly reinforced foundations and light reinforcement in masonry. Skukuza Safari Lodge September 2014 Report No: G

15 8. CONCLUSION It is clear from the investigation that the following constraints have to be noted by the Developer: Normal civil services Ground water seepage to be prevented due to high permeability of natural soil, Deep excavations should be shored to prevent collapsing of trench sides, Groundwater could be encountered in wet seasons, Specialized foundation design. For structures more than 3 storeys a detailed geotechnical investigation with preferably core drilling should be done. Skukuza Safari Lodge September 2014 Report No: G

16 9. REPORT PROVISIONS While every effort is made during the fieldwork phase to identify the different soil horizons, areas subject to a perched water table, areas of poor drainage, areas underlain by hard rock and to estimate their distribution, it is impossible to guarantee that isolated zones of poorer foundation material or harder rock have not been missed. For this reason this investigation has sought to highlight areas of potential foundation, groundwater and excavation problems, to provide prior warning to the developer. A competent person should inspect foundation and service excavations at the time of servicing the site and construction to determine the variance from the above assessment of the site. J.D. van Der Merwe Pr. Eng. (950456) Skukuza Safari Lodge September 2014 Report No: G

17 10. REFERENCES Stiff,et al, Guidelines for urban Engineering Geological Investigations. South African Institute for Engineering Geologist and South African Institution of Civil Engineers. Dept. of Community Development. Guidelines for Provision of Engineering Services for Residential Townships. National Home Builders Registration Council, Standards and Guidelines. NHBRC. SAICE Code of Practice: Foundations and Superstructures for Single Storey Residential Buildings of Masonry Construction. Joint Structural Division, Johannesburg, First Edition. Van der Merwe, D.H., The predictions of heave from the plasticity index and percentage clay fractions of soils. Civil Eng. In South Africa. June Topographical map 2430 PELGRIM S REST, scale 1 : Geological map 2431 DC SKUKUZA, scale 1 : Skukuza Safari Lodge September 2014 Report No: G

18 11. ANNEXURE Skukuza Safari Lodge September 2014 Report No: G

19 ANNEXURE A: LOCALITY Site Skukuza Safari Lodge September 2014 Report No: G

20 ANNEXURE B: SOIL PROFILES Skukuza Safari Lodge September 2014 Report No: G

21 Zone 1 Zone 2 Zone 1 Test Pit Layout Skukuza Safari Lodge September 2014 Report No: G

PROJECT: Skukuza Safari Lodge TEST PIT NO: 1 SITE: Skukuza LATITUDE : S24 59 34.2 LONGITUDE: E 31 35 20.

Transported. 300 400 500 600 700 Dry, Reddish brown, orange, medium grained, micro shattered, dense, Clayey sand that hardens with depth. Ferruginized.

22 PROJECT: Skukuza Safari Lodge TEST PIT NO: 1 SITE: Skukuza LATITUDE : S LONGITUDE: E ELEVATION: 279m DATE: 05/09/2014 EXCAVATED BY: TLB excavator Depth Lithology Description Dry, Brown, fine grained soft, loose, silty clayey sand. Roots apparent. Transported Dry, Reddish brown, orange, medium grained, micro shattered, dense, Clayey sand that hardens with depth. Ferruginized Moist with siphon water, light brown, grey, fine grained, micro shattered, dense, clayey sand - calcrete. Ground water at refusal level 2.2m Skukuza Safari Lodge September 2014 Report No: G

PROJECT: Skukuza Safari Lodge TEST PIT NO: 2 SITE: Skukuza LATITUDE : S24 59 32.1 LONGITUDE: E 31 35 20.

Roots apparent. Transported. 300 400 500 Dry, light brown, orange, medium grained, micro shattered, dense, Clayey sand that hardens with depth. Ferruginized.

23 PROJECT: Skukuza Safari Lodge TEST PIT NO: 2 SITE: Skukuza LATITUDE : S LONGITUDE: E ELEVATION: 278m DATE: 05/09/2014 EXCAVATED BY: TLB excavator Depth Lithology Description Dry, Brown, fine grained soft, loose, silty clayey sand. Roots apparent. Transported Dry, light brown, orange, medium grained, micro shattered, dense, Clayey sand that hardens with depth. Ferruginized Dry, light brown, grey, fine grained, micro shattered, dense, clayey sand - calcrete Skukuza Safari Lodge September 2014 Report No: G

PROJECT: Skukuza Safari Lodge TEST PIT NO: 3 SITE: Skukuza LATITUDE : S24 59 33.8 LONGITUDE: E 31 35 23.

Roots apparent. Transported. 300 400 500 Dry, Reddish brown, orange, medium grained, micro shattered, dense, Clayey sand that hardens with depth. Ferruginized.

24 PROJECT: Skukuza Safari Lodge TEST PIT NO: 3 SITE: Skukuza LATITUDE : S LONGITUDE: E ELEVATION: 280m DATE: 05/09/2014 EXCAVATED BY: TLB excavator Depth Lithology Description Dry, Dark Brown, fine grained soft, loose, silty clayey sandy gravel. Roots apparent. Transported Dry, Reddish brown, orange, medium grained, micro shattered, dense, Clayey sand that hardens with depth. Ferruginized. Dry, light brown, grey, fine grained, micro shattered, dense, clayey sand - calcrete Skukuza Safari Lodge September 2014 Report No: G

PROJECT: Skukuza Safari Lodge TEST PIT NO: 4 SITE: Skukuza LATITUDE : S24 59 32.2 LONGITUDE: E 31 35 22.

Roots apparent. Transported. 300 400 500 Dry, Reddish brown, orange, medium grained, micro shattered, dense, Clayey sand - Ferruginized.

25 PROJECT: Skukuza Safari Lodge TEST PIT NO: 4 SITE: Skukuza LATITUDE : S LONGITUDE: E ELEVATION: 278m DATE: 05/09/2014 EXCAVATED BY: TLB excavator Depth Lithology Description Dry, Brown, fine grained soft, loose, silty clayey sandy gravel. Roots apparent. Transported Dry, Reddish brown, orange, medium grained, micro shattered, dense, Clayey sand - Ferruginized Dry, light brown, grey, fine grained, micro shattered, dense, clayey sand calcrete Skukuza Safari Lodge September 2014 Report No: G

26 ANNEXURE C: TEST RESULTS Skukuza Safari Lodge September 2014 Report No: G

REPORT NO 12/115/D NOVEMBER 2012 GEOTECHNICAL INVESTIGATION FOR THE PROPOSED SOLAR PHOTOVOLTAIC FACILITY, GROOTVLEI POWER STATION

Consulting Geotechnical Engineers & Engineering Geologists P.O.Box 3557 Cramerview 2060. Tel: (011) 465-1699. Fax: (011) 465-4586. Cell 082 556 7302 & 076 966 8445 REPORT NO 12/115/D NOVEMBER 2012 GEOTECHNICAL