Soil Testing Services in Chennai
Introduction to Soil Testing for Construction
Soil testing is a vital step in any construction project, serving as the foundation—quite literally—for safe, durable, and cost-effective structures. Before any building begins, understanding the nature and behavior of the underlying soil is essential to ensure that it can support the proposed load and withstand environmental stresses over time.
In this blog, we explore the various soil testing services commonly used in the construction industry. Through a series of scientific tests conducted both on-site and in laboratories, soil testing evaluates critical parameters such as bearing capacity, moisture content, shear strength, settlement characteristics, and soil composition. These results guide engineers and architects in designing suitable foundations, selecting appropriate construction materials, and identifying potential geotechnical challenges early in the process.
Proper soil investigation not only enhances structural stability but also helps avoid future issues like foundation failure, cracks, or excessive settlement—making it a crucial first step in responsible construction planning.
Why Soil Testing is important before Construction?
It is important to check the quality of soil before you build your dream home. The ground where you are planning to make your dream home it is important to check the soil quality of it before your construction work begins.
Soil testing is primarily done to test the bearing capacity. The chemical and physical composition of the soil is checked during this process. The soil must have the ability to withstand the weight of the building. Quality of soil not only determines the bearing capacity but it ensures to determine the structure stabilization. Quality of Soil depends upon various factors such as weather, climate change and for the past years the land was deployed for what purpose and what was there previously.
The length and depth of the pillar determined during the foundation depending upon the quality of soil. The water level of the soil only can be determined from soil testing. Based on the soil testing reports quality of material can be decided. For example if due to moisture the area is prone to corrosion then it is important to choose only corrosion resistant TMT Bars for the construction.
Soil test is very important step of construction before it begins. If the soil testing is not done then the building will be exposed to unknown dangers and might the end result could be fatal.
Different types of Soil Testing for Construction
Various tests on soil are conducted to decide the quality of soil for building construction. Some tests are conducted in laboratory and some are in the field. Here we will discuss about the importance of various soil tests for building construction. The tests on soil are as follows.
1. Gravity test
Gravity of the soil is the ratio of unit weight of soil solids to that of the water.
Specific gravity of soil is the ratio of the unit weight of soil solids to that of the water. It is determined by many methods, and they are.
- Density bottle method
- Pycnometer method
- Gas jar method
- Shrinkage limit method
- Measuring flask method
There are quite a few methods by which the gravity test can be done, but the density bottle method and the pycnometer method are the simplest and most common ones to get the accurate result. In the pycnometer method, the vertex-specific gravity bottle is known as the pycnometer; it is weighed in 4 different cases, that is,
- Empty weight (M1)
- Empty + dry soil (M2)
- Empty + water + dry soil (M3)
- Pycnometer filled with water (M4)
At room temperature. From these 4 masses, specific gravity is determined by the below formula.
G = (M2 – M1) / (M2 – M1) – (M3 – M4)
2. Moisture Test
Moisture content, or water content, in soil is an important parameter for building construction. It is determined by several methods, and they are
- Oven-drying method
- Calcium carbide method
- Torsion balance method
- Pycnometer method
- Sand bath method
- Radiation method
- Alcohol method
In this method, samples are collected from the site and weighed before they are put in the oven before drying. After taking the weight, it is put on the oven and dried at 110°C + 5°C.
After 24 hours it is taken out from the oven and again weighed. The difference between two weights is noted, and the water or moisture content is determined from the difference in weight.
3. Atterberg Limits Test
The Atterberg limits test on soil is performed at 3 levels. The component for testing is done with fine grained soil and if any critical component from water is present then it can be determined with it. The three limits that are evaluated:
- Liquid Limit
- Plastic Limit
- Shrinkage Limit
* Liquid Limit Test:
The device that is used for this test is called Casagrande’s liquid limit device. This device consists of a cup with an up-and-down mechanism. The cup is moved up and down with the help of the handle, and the groove becomes closed at some point.
Once the water content of soil is determined, the procedure needs to be repeated 3 times. After that, a graph is to be drawn between log N and the water content of soil. Water content corresponding to N=25 is the liquid limit of soil.
* Plastic Limit Test:
In this test small balls need to be created by adding some water into them. After resting it for some time, the small balls are to be put into a glass plate and rolled to 3 mm in diameter.
Until the threads break when it rolls into a diameter that is less than 3 mm, water content is to be reduced. It is to determine the water content of the resultant soil, which value is nothing but the plastic limit.
* Shrinkage Limit Test:
The existing water in the soil is just sufficient to fill the voids. The below formula is used to do the shrinkage test on soil.
Ws = (M2 – M1)n – (V1 – V2) Pw / M2
- M1 = initial mass
- V1= initial volume
- M2= dry mass
- V2= volume after drying
- Pw = density of water
4. Dry Density Test
Dry Density Test in Soil is performed at 2 Levels
* Core Cutter Method
With the help of cylindrical core cutter of standard dimension is used to cut the soil from ground and the sample is tested by weighing it. Water content from that sample is determined and the dry density is calculated from the below relation.
P = (M/V) / 1+w
* Sand Replacement Method
In this method by excavation a hole is created and the soil dry density to be measured with it. The hole is filled with uniform sand of known dry density. Dividing the mass of sand poured into the hole with dry density of sand gives the volume of hole.
5. Proctor’s Compaction Test
Proctor’s test is conducted to determine compaction characteristics of soil. Compaction of soil is nothing but reducing air voids in the soil by densification. The degree of compaction is measured in terms of the dry density of soil.
In Proctor’s Compaction Test, a given soil sample is sieved through 20 mm and 4.75 mm sieves. Percentage passing 4.75 mm and percentage retained on 4.75 mm are mixed with certain proportions.
Add water to it and leave it in an airtight container for 20 hours. Mix the soil and divide it into 6–8 parts. Position the mold and pour one part of soil into the mold as 3 layers with 25 blows of ramming for each layer.
Remove the base plate and weigh the soil along with the mold. Remove the soil from the mold and take the small portion of the soil sample at different layers and conduct a water content test. From the values, find out the dry density of soil and water content, and draw a graph between them and note down the maximum dry density and optimum water content of the compacted soil sample at the highest point on the curve.
Role of Soil Testing in Foundations
Foundation is the first and important step of construction, a small defect or damage can fail or collapse the whole building. Foundation acts as a guardian to the building and protects it from any physical forces emerges in the subsoil. It helps to sustain and maintain the load bearings from the building to the ground.
The soil should consist of all physical and chemical properties to withstand the weight of the building. The soil testing and analysis helps to determine the rate of settlement and bearing capacity of the soil. These tests also help to define the length and depth of the pillars to lay the foundation.
The water content in the soil can only be known by soil testing, which helps to settle the level of humidity within the foundation. It’s necessary to have a note about soil movements, the way soil reacts in the presence and absence of water. Generally, soil movement is higher in clay soil than sandy soil.
Removal of vegetation also plays a very important role, presence of weeds, roots of old cut trees can cause soil movement in the land. These all factors affect the foundation settlement posing a threat to the structure.
Soil tests required for deep foundations
While the composition and depth of the bearing layer for shallow foundations may vary from one site to another, most pile foundations in a locally encounter similar deposits. Since pile capacity based on soil parameters is not as reliable from load tests, as a first step it is essential to obtain full information on the type, size, length and capacity of piles (including details of load – settlement graph) generally adopted in the locality. Correlation of soil characteristics (from soil investigation reports) and corresponding load tests (from actual projects constructed) is essential to decide the type of soil tests to be performed and to make a reasonable recommendation for the type, size, length and capacity of piles since most formulae are empirical.
If information about piles in the locality are not available or reliable, it may be necessary to drive a test pile and correlate with soil data. Generally, the following tests may be required to obtain certain required data:
1. Direct shear test
It is conducted to estimate the effective friction angle of cohesionless soil. Nonetheless, there are correlations that are developed to evaluate the effective friction angle of cohesionless soil.
2. Standard penetration test (SPT)
It is performed to determine the cohesion (and consequently the adhesion) to determine the angle of friction (and consequently the angle of friction between soil and the pile and also the point of resistance) for each soil stratum of cohesion less soil of soil.
3. Static cone penetration test (CPT)
This test conducted to determine the cohesion (and subsequently the adhesion) for soft cohesive soils and to check with SPT result for fine to medium sands. Hence for strata encountering both cohesive and cohesion less soils, both SPT and CPT tests are required.
4. Vane shear test
It is used to estimate the undrained in-situ shear strength of impervious clayey soils.
5. Undrained triaxial shear strength
It is carried out on undisturbed soil samples (obtained with thin-walled tube samplers) to determine cohesion (c) and angle of internal friction (φ) for clayey soils. Procedures for conducting this test are provided by ASTM D 2850-03, 2004.
In the case of driven piles proposed for stiff clays, it is necessary to check with the (cohesion, c) and (angle of internal friction, φ) from remolded samples. Drained shear strength parameters are also determined to represent the in-situ condition of soil at the end of the construction phase. Details of this test procedure can be found in ASTM D4767-02, 2004.
6. Pressure meter test
It is performed to determine the stress- strain curve of horizontal loading. The equipment is either inserted into pre-drilled borehole or a self-boring pressure meter is used. Unless the soil is isotropic, the same value cannot be adopted for the vertical direction. This test is performed specifically for piles that subjected to lateral loading.
7. Ground water condition and permeability of soil
Ground water condition and soil permeability influence the choice of pile type to be recommended. Hence the level at which water in the bore hole remains are noted in the bore logs. Since permeability of clay is very low, it takes several days for water in the drill hole to rise upto ground water table. Ground water samples need to be tested to consider the possible chemical effects on concrete and the reinforcement. Result of the cone penetration test for the same soil show substantial scatter. Hence, they need to be checked with supplementary information from other exploration methods.
8. Pile Load Test
Pile load testing is a critical field test performed to determine the load-carrying capacity of piles used in deep foundation systems. This test helps verify the design assumptions and assess the structural integrity of piles under vertical loads. Conducted either as a static load test or a dynamic load test, it provides essential data such as settlement behavior, ultimate load capacity, and pile-soil interaction. The procedure follows standards like IS 2911 (Part IV) or ASTM D1143.
9. Geophysical Surveys
Geophysical surveys are non-invasive investigations used to map subsurface conditions by measuring physical properties such as seismic velocity, resistivity, and magnetic fields. Techniques like Seismic Refraction, Electrical Resistivity Imaging (ERI), and Ground Penetrating Radar (GPR) are commonly used to assess soil stratification, rock profiles, groundwater levels, and voids. These surveys support geotechnical site investigations by providing continuous data over large areas, reducing the need for excessive drilling.
10. Plate Load Tests
The plate load test is a field test conducted to evaluate the bearing capacity and settlement characteristics of soil under a given load. A rigid steel plate (typically 300–750 mm in diameter) is placed at the foundation level and loaded incrementally. The resulting settlement is measured to establish safe bearing pressure and modulus of subgrade reaction (k-value). It is particularly useful for designing shallow foundations and follows guidelines such as IS 1888 or ASTM D1194.
Soil Tests for Shallow and Raft Foundations
Soil tests required to determine safe bearing capacity of shallow foundations and raft foundations are discussed here. These tests are as per IS 6403 – 1981. Apart from ascertaining the highest level ever reached by the groundwater table and tests for classification of soil as per IS 1498 – 1970 based on grain size analysis as per IS 2720 (Part –IV)– 1985, index properties of soil as per IS 2720 (Part-V) – 1985, the following tests are required to determine safe bearing capacity based on shear strength consideration:
1. Standard penetration test
as per IS 2131–1991 for coarse-grained/fine-grained cohesionless soils with semi-pervious clayey soils (i.e. soils with clay up to 30%).
2. Direct shear test (controlled strain)
As per IS 2720 (Part – 13) – 1986. Consolidated undrained tests for cohesive and for soils and consolidated drained tests for cohesion less soils. The results may be compared with standard penetration test / static cone penetration test results. Since there is escape of pore water during box shear, partial drainage vitiates the consolidated undrained test. Hence this test is not exact for semi-pervious soils such as clayey sands / silts (i.e. with clay more than 15% but less than 30%). For such soils, triaxial tests are required if shear strength is critical criterion.
3. Static cone penetration test
As per IS 4968 (Part -3) – 1976 for foundations on non-stiff clayey soils such as fine grained soils (i.e. more than 50% passing through 75 micron sieve). In fine and medium coarse sands such tests are done for correlation with standard penetration test and to indicate soil profiles at intermediate points.
4. Unconfined compressive strength test
As per IS 2720 (Part-10) – 1973 for highly cohesive clays except soft / sensitive clays.
5. Vane shear tests
For impervious clayey soils except stiff or fissured clays.
6. Triaxial shear tests
For predominantly cohesive soils. If shear strength is likely to be critical.
Soil Tests for Shallow Foundations
Tests required to determine allowable bearing pressure for shallow foundations on settlement consideration:
1. Standard penetration test as stated above.
2. Consolidation test
As per IS 2720 (Part-15) if the settlement of clayey layer(s) calculated on the basis of liquid limit and in-situ void ratio indicates that settlement may be critical. A consolidation test is not required if the superimposed load on foundation soil is likely to be less than pre-consolidation pressure (assessed from liquidity index and sensitivity or from un-confined compressive strength and plasticity index)
3. Plate load tests
As per IS 1888–1982 for cohesionless soils and soils where neither standard penetration test nor consolidation test is appropriate, such as for fissured clay/rock, clay with boulders, etc.
Soil Tests Required for Raft Foundations
Apart from other tests for shallow foundations, the following soil tests are required especially for raft foundations:
1. Static cone penetration test
As per IS 4968 (Part-3) – 1976 for cohesionless soils to determine modulus of elasticity as per IS 1888 – 1982.
2. Standard penetration test
As per IS 2131 – 1981 for cohesionless soils and soils to determine modulus of sub-grade reaction.
3. Unconfined compressive strength test
As per 2720 (Part -10) – 1973 for saturated but no pre-consolidated cohesive soil to determine modulus of sub-grade reaction.
4. Plate load test
As specified in IS 2950 (Part -1) – 1981¸ as per IS 1888 – 1982 where tests at Sl. No. – 1 to 3 above are not appropriate such as for fissured clays / clay boulders.
5. Pumping tests
In the case of deep basements in pervious soils, permeability is determined from pumping tests. This is required to analyze the stability of deep excavation and to design an appropriate dewatering system.
Why Soil Testing is Important before Construction?
When you decide to construct a house, soil testing is one of the first things to be done after buying a plot of land.
Soil testing is the first step in construction planning to ensure whether the plot of land is suitable for constructing any structure to avoid dreadful phenomena in future like The leaning Tower of Pisa.
The type of tests on soil reveals the physical and engineering properties of soil that help to determine the type of foundation to be laid for construction. Knowing moisture content, mineral presence, density, permeability and bearing capacity of the soil gives an idea of working considerations for foundations and earthworks. Like higher sulphur content in the soil requires cement that provides resistance to sulphur such as Sulphate-resisting Portland Cement (SRPC).
Conclusion: Book Soil Testing Services in Chennai
Soil testing plays a vital role in the success of any construction project. Understanding the properties of soil—such as its bearing capacity, moisture content, permeability, and shear strength—is crucial before laying the foundation of any structure. At Noah Infrastructures, the top construction company in Chennai, while we do not directly offer soil testing services, we recognize its importance in the larger construction process. As a leading contractor, we are committed to quality and structural excellence, and we emphasize the need for proper soil evaluation in every project we execute. For builders, developers, and property owners looking for reliable soil and material testing and reliable construction material verification, we recommend Jacob Engineers – Structural and Material Testing Division, a trusted name in Chennai, with NABL-accredited facilities and an experienced team in testing soil, concrete, steel, and other construction materials.
By working with experts like Jacob Engineers, you ensure that your project’s foundation rests on verified, science-backed data—eliminating guesswork and reducing long-term risks. Whether you’re planning a small residential building or a large commercial complex, never overlook the value of comprehensive soil testing in your construction journey.
