Hawzheen Consultant Engineer

25/01/2026

🟦 WHAT IS GEOTECHNICAL INVESTIGATION WORKS?
Geotechnical Investigation =
👉 Studying the soil and ground conditions before construction
👉 To know how strong the soil is and what type of foundation is needed
In simple words:
➡️ It tells engineers what is under the ground.
➡️ It checks if the soil can carry the weight of the building, tank, pipeline, or structure.
➡️ It prevents future problems like settlement, cracks, sliding, or collapse.
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🟩 WHY IS GEOTECHNICAL INVESTIGATION IMPORTANT?
Because different soils behave differently:
• Some are strong
• Some are weak
• Some expand with water
• Some can cause sinking
Geotechnical investigation helps engineers design the safe foundation.
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🟫 WHAT ARE THE MAIN ACTIVITIES?
1️⃣ Soil Boreholes (Drilling)
Machines drill holes into the ground (5m – 40m deep).
Soil samples are taken at different depths.
Meaning:
👉 To know what type of soil exists below the surface.
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2️⃣ Soil Sampling
Two types:
• Disturbed sample (loose soil)
• Undisturbed sample (intact soil)
Meaning:
👉 Samples are sent to the lab for testing.
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3️⃣ Laboratory Testing
Tests include:
• Moisture content
• Grain size analysis
• Atterberg limits
• Density
• Shear strength
• Compaction
• Bearing capacity
Meaning:
👉 To measure how the soil behaves under load.
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4️⃣ Field Tests
• SPT (Standard Pe*******on Test)
• Plate load test
• Cone pe*******on test (CPT)
• Permeability test
Meaning:
👉 To check the strength of the soil directly on site.
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5️⃣ Groundwater Level Check
They measure how deep the water table is.
Meaning:
👉 This affects foundation design, dewatering, and basement works.
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6️⃣ Geotechnical Report
A final report that includes:
• Soil layers
• Lab + field test results
• Bearing capacity
• Allowable foundation loads
• Recommended foundation type (raft, piles, strip)
• Groundwater level
• Excavation recommendations
Meaning:
👉 This report tells engineers how to design the foundation safely.
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🟧 SUMMARY IN ONE LINE
Geotechnical Investigation = Testing the soil to know if it can support the structure and what foundation is required.

25/01/2026

🟦🟦 WHAT IS TOPOGRAPHIC SURVEY WORK? 🟦🟦

👉 TOPOGRAPHIC SURVEY = MEASURING THE LAND LEVELS + ALL FEATURES ON THE SITE
It tells you:
• Ground elevations (levels)
• Slopes of the land
• Buildings, fences, poles
• Roads, utilities, manholes
• Trees and natural features
This survey is done before construction to understand the ground condition.
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🟩🟩 STEPS OF TOPOGRAPHIC SURVEY WORK 🟩🟩
1️⃣ PRE-SURVEY PREPARATION
• Collect drawings and coordinates
• Check old survey info
• Prepare GPS/RTK, Total Station, Auto-Level
• Plan safety and site access
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2️⃣ SETUP CONTROL POINTS
• Place fixed reference points around the site
• Each point has Northing / Easting / Elevation
• These control points are used for all measurements
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3️⃣ FIELD SURVEY WORK (DATA COLLECTION)
Survey team measures:
• Spot levels (ground levels)
• Break lines (edges of slopes, roads)
• Roads & utilities
• Boundaries
• Buildings / structures
Using Total Station + GPS/RTK equipment.
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4️⃣ PROCESSING THE DATA
• Download survey files
• Check accuracy
• Create a 3D surface model (TIN)
• Prepare AutoCAD layers
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5️⃣ PREPARE THE FINAL TOPO MAP
Map includes:
• Contour lines
• Spot levels
• Utilities
• Roads & structures
• Coordinates & Elevations
• Legend + Scale
Delivered usually as DWG + PDF.
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6️⃣ FINAL DELIVERABLES
✔ Topographic drawing
✔ Control points report
✔ Benchmark details
✔ Survey photos
✔ Digital 3D ground surface

🟦 1️⃣ Topographic Drawing (DWG + PDF)
This is the main map of the land.
It shows:
• Ground levels (spot levels)
• Contours (lines showing slope)
• Roads, utilities, manholes
• Buildings, fences, trees
• Boundaries
• Coordinates (N/E)
Meaning:
👉 It is the final topographic map used by engineers for design and construction.
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🟩 2️⃣ Control Points Report
A document listing all the survey control points used on site.
For each point, it shows:
• Point name (CP1, CP2, BM1…)
• Coordinates (Northing / Easting)
• Elevation (Level)
• Type (Nail, Bench, Concrete point)
• Photo of the point
Meaning:
👉 It tells engineers where the reference points are and the exact coordinates, so they can repeat the survey later.
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🟫 3️⃣ Benchmark (BM) Details
A Benchmark = a fixed reference point for elevation.
BM report includes:
• BM number
• Elevation (Ex. 102.550 m)
• Location description
• Photo
Meaning:
👉 It is the starting elevation for all level works on the project.
Without a benchmark, no accurate leveling can be done.
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🟧 4️⃣ Survey Photos
Real photos taken during the survey showing:
• Control points
• Benchmarks
• Site condition
• Equipment setup
Meaning:
👉 Visual proof of the site condition and the location of control points.
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🟪 5️⃣ Digital Surface Model (DSM or TIN Surface)
This is a 3D model of the ground created from the survey points.
It is used for:
• Earthwork calculations
• Design of drainage
• Road leveling
• Excavation volume estimation
Meaning:
👉 A computer 3D shape of the land that helps engineers calculate cut/fill and design the site.
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🟫 6️⃣ Raw Survey Data (optional)
Data directly from the instrument:
• GPS files
• Total Station points
• CSV point files
Meaning:
👉 If someone wants to check accuracy or redo the survey, they use this raw data.

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