Geo-technical Study for Lucknow Residential Building
Budget: ₹1,500 – ₹12,500 INR
Project Title:
Geotechnical Investigation and Slab Specification Report for a Residential Building in Lucknow
Table of Contents:
Introduction
Objectives
Site Description
Geotechnical Investigation
4.1 Soil Sampling
4.2 Field Tests
4.3 Laboratory Tests
Soil Profile
Analysis of Soil Properties
Bearing Capacity
Groundwater Conditions
Foundation Recommendations
Slab Specifications
10.1 Type of Slab
10.2 Materials Used
10.3 Thickness and Reinforcement
10.4 Design Load Considerations
10.5 Construction Method
10.6 Safety Measures
Conclusion
References
1. Introduction
This report outlines the findings of a geotechnical investigation conducted for the proposed residential building in Lucknow. The purpose of this investigation is to understand the soil characteristics, determine the bearing capacity, and design suitable foundation and slab specifications to ensure structural safety and economic feasibility.
2. Objectives
To study the subsurface soil conditions at the project site.
To assess the engineering properties of the soil through sampling and testing.
To estimate the bearing capacity of the soil for safe foundation design.
To recommend a suitable type of foundation based on soil strength and water table levels.
To design the slab specifications including thickness, reinforcement, and construction technique.
3. Site Description
The project site is a rectangular residential plot located in Gomti Nagar, Lucknow, measuring approximately 30m x 45m. The area is flat with no significant slopes. No nearby water bodies are present. The site was previously unused and covered with natural vegetation.
4. Geotechnical Investigation
4.1 Soil Sampling
Two boreholes were drilled to a depth of 6 meters using a rotary drilling machine. Disturbed and undisturbed soil samples were collected at 1.5-meter intervals for testing.
4.2 Field Tests
The Standard Penetration Test (SPT) was conducted in boreholes. Results showed SPT-N values ranging from 12 in the upper loose layer to 25 in the deeper dense layer. These indicate medium-dense soil suitable for shallow foundations.
4.3 Laboratory Tests
Collected samples underwent the following tests:
Moisture Content: 15–22%
Atterberg Limits:
- Liquid Limit (LL): 35%
- Plastic Limit (PL): 20%
- Plasticity Index (PI): 15%
Grain Size Analysis: Predominantly silty sand (60%) with clay (40%)
Specific Gravity: 2.65
Bulk Density: 1.9 g/cc
5. Soil Profile
0–2 m: Loose silty sand
2–4.5 m: Medium stiff clay
Below 4.5 m: Dense clayey sand
No organic content, rocks, or boulders were found. Soil is moderately permeable with low shrink-swell potential.
6. Analysis of Soil Properties
The soil's moderate plasticity and grain structure offer good stability. The top silty sand layer requires compaction. The underlying stiff clay and dense sand provide a solid base for load transfer.
7. Bearing Capacity
Using Terzaghi’s formula and SPT correlations, the Safe Bearing Capacity (SBC) was determined to be 180 kN/m² at a depth of 1.5 meters. Factor of safety = 3.
8. Groundwater Conditions
Groundwater table was found at 4.5 meters below the ground surface. Since the proposed foundation is within 1.5 m, there is no immediate threat of water ingress. Proper drainage and waterproofing should be ensured.
9. Foundation Recommendations
A shallow strip foundation is suitable for this project. Recommended foundation depth: 1.2 to 1.5 meters. A Plain Cement Concrete (PCC) base layer of 100 mm should be laid to ensure even load distribution.
10. Slab Specifications
10.1 Type of Slab
Ground floor Reinforced Cement Concrete (RCC) slab resting on compacted subgrade.
10.2 Materials Used
Concrete Mix: M25 (1:1:2)
Steel Reinforcement: Fe500 TMT bars
Cover Blocks: 25 mm minimum cover
Waterproofing Membrane: 2-layer polymer coating post-curing
10.3 Thickness and Reinforcement
Slab Thickness: 150 mm
Main Reinforcement: 10 mm bars @ 150 mm c/c (bottom)
Distribution Steel: 8 mm bars @ 200 mm c/c (top)
Anti-crack mesh: 100 mm x 100 mm welded mesh at surface
10.4 Design Load Considerations
Live Load: 5 kN/m² (residential standard per IS 875)
Dead Load: 3.5–4.0 kN/m² including slab self-weight
Total Load: 8–9 kN/m²
Designed with proper load combinations for safety and serviceability.
10.5 Construction Method
Clear and level the site.
Compact subgrade to 95% MDD.
Lay PCC base layer.
Install shuttering and reinforcement.
Pour concrete and vibrate properly.
Keep slab wet for minimum 7 days (curing).
Apply waterproofing layer after 14 days.
10.6 Safety Measures
All workers must wear PPE (helmets, gloves, boots).
Lifting of steel and concrete pouring must follow site safety norms.
Safety signage to be installed.
Site supervisor to ensure structural checks before and during casting.
11. Conclusion
The geotechnical investigation confirms the soil’s ability to support a shallow foundation. With appropriate slab thickness, reinforcement, and waterproofing, the structure will have good durability and strength. A ground-bearing RCC slab is recommended, ensuring economic construction with safety.
12. References
IS 456:2000 – Code of Practice for Plain and Reinforced Concrete
IS 1893 – Criteria for Earthquake Resistant Design
IS 6403 – Determination of Bearing Capacity of Shallow Foundations
IS 875 – Code of Practice for Structural Safety: Loads
Laboratory Soil Testing Manual – NITTR Publication
Geotechnical Investigation and Slab Specification Report for a Residential Building in Lucknow
Table of Contents:
Introduction
Objectives
Site Description
Geotechnical Investigation
4.1 Soil Sampling
4.2 Field Tests
4.3 Laboratory Tests
Soil Profile
Analysis of Soil Properties
Bearing Capacity
Groundwater Conditions
Foundation Recommendations
Slab Specifications
10.1 Type of Slab
10.2 Materials Used
10.3 Thickness and Reinforcement
10.4 Design Load Considerations
10.5 Construction Method
10.6 Safety Measures
Conclusion
References
1. Introduction
This report outlines the findings of a geotechnical investigation conducted for the proposed residential building in Lucknow. The purpose of this investigation is to understand the soil characteristics, determine the bearing capacity, and design suitable foundation and slab specifications to ensure structural safety and economic feasibility.
2. Objectives
To study the subsurface soil conditions at the project site.
To assess the engineering properties of the soil through sampling and testing.
To estimate the bearing capacity of the soil for safe foundation design.
To recommend a suitable type of foundation based on soil strength and water table levels.
To design the slab specifications including thickness, reinforcement, and construction technique.
3. Site Description
The project site is a rectangular residential plot located in Gomti Nagar, Lucknow, measuring approximately 30m x 45m. The area is flat with no significant slopes. No nearby water bodies are present. The site was previously unused and covered with natural vegetation.
4. Geotechnical Investigation
4.1 Soil Sampling
Two boreholes were drilled to a depth of 6 meters using a rotary drilling machine. Disturbed and undisturbed soil samples were collected at 1.5-meter intervals for testing.
4.2 Field Tests
The Standard Penetration Test (SPT) was conducted in boreholes. Results showed SPT-N values ranging from 12 in the upper loose layer to 25 in the deeper dense layer. These indicate medium-dense soil suitable for shallow foundations.
4.3 Laboratory Tests
Collected samples underwent the following tests:
Moisture Content: 15–22%
Atterberg Limits:
- Liquid Limit (LL): 35%
- Plastic Limit (PL): 20%
- Plasticity Index (PI): 15%
Grain Size Analysis: Predominantly silty sand (60%) with clay (40%)
Specific Gravity: 2.65
Bulk Density: 1.9 g/cc
5. Soil Profile
0–2 m: Loose silty sand
2–4.5 m: Medium stiff clay
Below 4.5 m: Dense clayey sand
No organic content, rocks, or boulders were found. Soil is moderately permeable with low shrink-swell potential.
6. Analysis of Soil Properties
The soil's moderate plasticity and grain structure offer good stability. The top silty sand layer requires compaction. The underlying stiff clay and dense sand provide a solid base for load transfer.
7. Bearing Capacity
Using Terzaghi’s formula and SPT correlations, the Safe Bearing Capacity (SBC) was determined to be 180 kN/m² at a depth of 1.5 meters. Factor of safety = 3.
8. Groundwater Conditions
Groundwater table was found at 4.5 meters below the ground surface. Since the proposed foundation is within 1.5 m, there is no immediate threat of water ingress. Proper drainage and waterproofing should be ensured.
9. Foundation Recommendations
A shallow strip foundation is suitable for this project. Recommended foundation depth: 1.2 to 1.5 meters. A Plain Cement Concrete (PCC) base layer of 100 mm should be laid to ensure even load distribution.
10. Slab Specifications
10.1 Type of Slab
Ground floor Reinforced Cement Concrete (RCC) slab resting on compacted subgrade.
10.2 Materials Used
Concrete Mix: M25 (1:1:2)
Steel Reinforcement: Fe500 TMT bars
Cover Blocks: 25 mm minimum cover
Waterproofing Membrane: 2-layer polymer coating post-curing
10.3 Thickness and Reinforcement
Slab Thickness: 150 mm
Main Reinforcement: 10 mm bars @ 150 mm c/c (bottom)
Distribution Steel: 8 mm bars @ 200 mm c/c (top)
Anti-crack mesh: 100 mm x 100 mm welded mesh at surface
10.4 Design Load Considerations
Live Load: 5 kN/m² (residential standard per IS 875)
Dead Load: 3.5–4.0 kN/m² including slab self-weight
Total Load: 8–9 kN/m²
Designed with proper load combinations for safety and serviceability.
10.5 Construction Method
Clear and level the site.
Compact subgrade to 95% MDD.
Lay PCC base layer.
Install shuttering and reinforcement.
Pour concrete and vibrate properly.
Keep slab wet for minimum 7 days (curing).
Apply waterproofing layer after 14 days.
10.6 Safety Measures
All workers must wear PPE (helmets, gloves, boots).
Lifting of steel and concrete pouring must follow site safety norms.
Safety signage to be installed.
Site supervisor to ensure structural checks before and during casting.
11. Conclusion
The geotechnical investigation confirms the soil’s ability to support a shallow foundation. With appropriate slab thickness, reinforcement, and waterproofing, the structure will have good durability and strength. A ground-bearing RCC slab is recommended, ensuring economic construction with safety.
12. References
IS 456:2000 – Code of Practice for Plain and Reinforced Concrete
IS 1893 – Criteria for Earthquake Resistant Design
IS 6403 – Determination of Bearing Capacity of Shallow Foundations
IS 875 – Code of Practice for Structural Safety: Loads
Laboratory Soil Testing Manual – NITTR Publication