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GEOLOGICAL - GEOTECHNICAL SURVEY

1. General

The main objective of this research is to provide information on the ground conditions at

the site and geotechnical engineering recommendations on material characteristics of the

soil, sufficient to enable foundation design by our structural engineer.

Substation locations and a spread of positions across the areas where PV panels are

proposed, considerate of the anticipated geology, should be investigated so as to gather the

following information:

• Subsurface soil conditions mechanical properties

• Strata description

• Groundwater conditions

• Allowable soil bearing capacity checks

A factual report should be provided including the findings of the fieldwork and results of

laboratory testing.

Note that it should be verified with the Geological and Geotechnical study the compatibility

of the selected foundation taking into consideration all the mechanical and chemical

properties of the ground.

The proposed investigation should be based on the specification provided, and involves

window sampling (WS) boreholes and dynamic penetrating testing (DPT), with geotechnical

laboratory analysis to provide additional information on the soil properties.

All the works required shall include all the provisional labor and measures necessary for

executing the works in full observance of safety.

Finally, site investigation and laboratory testing procedure and tests should follow all the

applicable standards and regulations.

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2. Study Area Location

The field comprising a total area of approximately 648.300m² lies approximately 9km east of

David, Republic of Panama (8°22'41.40"N, 82°19'53.24"W). However, the study area where

GWB aims to implement photovoltaic panels, covers approximately 590.730 m² (pic. 2).

Picture 1: Project Location

Picture 2: PV Plant Area

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3. Scope of Work

To undertake the geotechnical assessment, the following scope of work should be taken into

account:

� Desk study

Prior to mobilizing to site, all the available information from records and accessible sources

(geological base data, tectonic environment, regional earthquake research and earthquake

data), together with that provided will be considered and included in the factual report.

� Site Investigation

1. Provision of small works crew with dual purpose window sampling/dynamic penetration

testing rig to undertake the following:

- x 10 number of Window sample (WS) boreholes to a maximum depth of 3.0m (depth

depends on exact ground conditions encountered). Note that the typical driven pile’s

embedment depth is only 1,50~2 00m). The number of samples should be the minimum

within the area that pv structures will cover – construction limits (see drawing

“GB.01.PA.P.02014.03.001.00_Proposed Layout” as a reference).

- x 10 number of Dynamic probing (DPSH) and SPT to an approximate depth of 4-5m.

Note that depth depends on exact ground conditions encountered and that the typical

driven pile’s embedment depth is only 1,50~2 00m. The number of DPSHs / SPTs should

be the minimum within the area that pv structures will cover – construction limits (see

drawing “GB.01.PA.P.02014.03.001.00_Proposed Layout” as a reference). However, the

DPTs should be carried out adjacent to the WS boreholes in order to provide information

on the density of the soils encountered.

2. Provision of a tracked excavator and operator to undertake x 10 number of Trial pits

(TP) of about 0,60m width to a maximum of 3.0m depth concerning natural soil. The

exact location of each trial pit will be chosen in order to cover the area of the pv project.

3. Photographs will be taken of a few boreholes and trial pits so as to provide images of the

strata in the report from which to consider the stability.

4. Soils samples will be retrieved (from each TP or WS position) and strata described.

Collect samples in plastic liners for transport back to the laboratory.

5. Provision of a technician and equipment to undertake x 15 in situ CBR tests on

undisturbed and uncompressed samples and not on compacted material. In situ

tests will be carried out alongside of the internal road and all the platforms (see

drawing “GB.01.PA.P.02014.03.001.00_Proposed Layout” as a reference).

6. Logging of the soils and sub sampling for laboratory testing and strata description.

7. Ground water level observation is also required.

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The exploratory locations shall be spread across the site in order to give wide coverage of

the prevalent ground conditions for the proposed photovoltaic panels and to target specific

infrastructure locations.

Note that the soils should be backfilled with lightly compacted arising upon completion

(WS, DPSH, trial pits). Also, Window Sample exercise shall be excluded in case soil samples

and strata description can be retrieved from Trial pits.

� Laboratory Testing

Samples collected from the window sampler boreholes / trial pits from across the site shall

be scheduled for geotechnical laboratory analysis.

1. Liquid and plastic limits (Atterberg limit determination) � 10 samples

2. Soil classification � 10 samples

3. Natural Moisture content � 10 samples

4. Particle size distribution tests. Spreadsheets and graphs results will be presented. � 10

samples

5. Undrained shear strength determinations (Cu) in undrained triaxial compression

strength tests till the depth of 1,50m � 10 samples

6. Chemical tests for PH, Organic Matter Content, soluble sulphate, magnesium, chloride

and nitrate � 5 samples for each analysis

7. Electrical conductivity tests � 3 samples

8. Soil Thermal resistivity (K*m/W) � 3 samples

� Factual Report

The factual report based on the findings on the fieldwork and results of the laboratory

testing shall provide the following information:

- Desk study – Land preliminary information (geology, hydrology, hydrogeology, etc.)

- Site information, field survey

- Determination of the irregularities that may occur in the field, as unknown cavities,

presence of organic matter, faults, etc.

- Tectonic environment, regional seismic characteristics, seismic profile

- Description of the research conducted, specifying the data obtained in the surveys.

- Mechanical properties of the soil (γdry, γsat, Cu, φ, E, etc.)

- Chemical properties of the soil

- Design soil profile and strata description

- Allowable soil bearing capacity for shallow foundations

- Groundwater conditions

- Geotechnical considerations