Introduction to Standard Penetration Test (SPT)
The Standard Penetration Test (SPT) is one of the most widely used in-situ soil tests in Nigeria. It provides essential data for foundation design, soil classification, and geotechnical analysis. At Liscon Geotechnical Limited, we deliver precise and reliable SPT services to meet project requirements across the country. If you need expert geotechnical survey services in Nigeria, reach us at +2349074528661, liscongeotech@gmail.com, or www.liscon.com.ng.
Equipment Used for SPT in Nigeria
SPT requires a drilling rig, split spoon sampler, standard hammer, and borehole casing. The hammer, usually 63.5 kg, falls freely from a height of 760 mm. Each blow drives the sampler into the soil, giving accurate penetration resistance values. Finally, proper equipment maintenance ensures consistent and dependable results.
Step-by-Step SPT Procedure
- Drill a borehole to the desired test depth using rotary or percussion drilling.
- Clean the bottom of the borehole to avoid loose cuttings.
- Drive the split spoon sampler 450 mm into the soil using the standard hammer.
- Record the number of blows required for each 150 mm penetration.
- Discard the first 150 mm reading. Then, sum the last two readings to get the N-value.
- Collect soil samples for laboratory analysis.
Key Parameters Measured
The main thing measured in an SPT is the N-value. It shows how many blows it takes to push the sampler into the soil. The N-value is very important for understanding soil properties.
| N-Value Range (Sand) | Relative Density | N-Value Range (Clay) | Consistency |
| 0-4 | Very loose | Below 2 | Very Soft |
| 4-10 | Loose | 2-4 | Soft |
| 10-30 | Medium dense | 4-8 | Medium stiff |
| 30-50 | Dense | 8-15 | Stiff |
| Above 50 | Very dense | 15-30 | Very stiff |
| – | – | Above 30 | Hard |
Above all, the N-value helps estimate soil density, strength, and liquefaction risk. Knowing these are vital for geotechnical design and analysis.
Importance of Standard Penetration Test in Nigeria
SPT data help determine soil bearing capacity and settlement characteristics. It identifies weak layers that may affect construction stability. With Nigeria’s diverse soil conditions, SPT offers reliable guidance for foundation design and geotechnical recommendations.
Best Practices for Accurate SPT Results
- Use calibrated equipment to avoid incorrect readings.
- Ensure proper borehole cleaning before testing.
- Conduct tests at required intervals, typically every 1.5 m or at change of strata.
- Engage professional geotechnical engineers like Liscon Geotechnical Limited for quality assurance.
Why Choose Liscon Geotechnical Limited?
We combine advanced technology, experienced engineers, and strict quality standards to deliver dependable geotechnical data. Our services cover SPT, soil testing, and foundation analysis for residential, industrial, and infrastructure projects.
Looking for More Advanced Soil Testing?
- For detailed profiling and continuous data, see our guide on Cone Penetration Test Procedure in Nigeria.
- Not sure which test suits your project? See our guide on SPT vs CPT in Nigeria.
Contact Us Today
Address: 25, Sonlife Street, Egbelu, Port Harcourt, Rivers State, Nigeria
Phone: +234 9074528661
Email: liscongeotech@gmail.com
Website: www.liscon.com.ng
Conclusion
The Standard Penetration Test remains a reliable and cost-effective method for soil investigation in Nigeria. By delivering accurate N-values and soil samples, it provides essential data for safe foundation design. At Liscon Geotechnical Limited, we combine expertise, advanced equipment, and strict quality control to ensure dependable SPT results for your project. Contact us today to book a Standard Penetration Test and get accurate geotechnical data for your next project.
FAQs
How deep can Standard Penetration Tests be carried out in Nigeria?
SPT can be performed up to 30 m or more, depending on site conditions and project needs.
How long does an SPT investigation take?
A typical test takes a few hours per borehole, depending on soil type and drilling depth.
What is the cost of Standard Penetration Test in Nigeria?
Costs vary with location, depth, and project specifications. Contact Liscon Geotechnical Limited for a tailored quote.
