Soil classification is the first step in understanding the properties of soil. At SRTL, we perform several key classification tests:

• Atterberg Limits: The Atterberg limits include three key measurements: the liquid limit (LL), plastic limit (PL), and shrinkage limit (SL). The liquid limit is defined as the moisture content at which a soil transitions from a plastic state to a liquid state. Typically performed using the Casagrande apparatus and involves measuring the number of blows needed to close a groove in a soil sample. The plastic limit is the moisture content at which a soil changes from a semi-solid state to a plastic state. This limit is established by rolling a soil sample into a thread until it crumbles at a diameter of approximately 3 mm. The shrinkage limit represents the moisture content at which further loss of water does not result in a decrease in the volume of the soil. Conducted using a shrinkage dish to observe volume changes in a soil sample as it dries. This limit is essential for understanding the volume changes that may occur in clayey soils during drying and wetting cycles. Each of these limits provides insights into the behaviour of soil under varying moisture conditions. The resulting plasticity index aids in classifying soil types and assessing their suitability for construction.
• Specific Gravity:Specific gravity is a critical parameter in geotechnical engineering, as it influences calculations related to soil density and void ratio. For coarse-grained soils, specific gravity is determined using a pycnometer, while for fine-grained soils, we employ density bottles. In the case of fine-grained soils, we utilize vacuum pumps to evacuate air bubbles that can affect the accuracy of the measurements. This meticulous approach ensures that the readings reflect the true density of the soil particles without interference from entrapped air.
• Grain Size Analysis: Uses sieve analysis to determine particle size distribution for coarse grained soil, vital for understanding soil composition, permeability, compaction, and shear strength. To determine the particle size distribution of fine-grained soils, we utilize the hydrometer method as part of our sedimentation analysis. This method relies on Stokes' law, which relates the settling velocity of particles in a fluid to their size. The hydrometer measures the density of the suspension at various depths over time, allowing us to calculate the percentage of particles retained at each size.
• Free Swell Index: This test evaluates the potential volume changes in expansive clays when they absorb moisture. Recognizing swell potential is essential for designing foundations and addressing heave-related issues