Subsoil Investigation and Laboratory

Subsoil Investigation and Laboratory

GnS

Our subsoil investigation team is well-trained engineers and technicians who shall do subsoil investigation in the field and lab. This part is a non-profit service provided by us for our design projects. We don’t provide this service to other projects commercially. The soil test data must be reliable based on which we do design. So, we always request clients to take this service from us if they select us as designer.


The standard penetration test (SPT) is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil. ... The test provides samples for identification purposes and provides a measure of penetration resistance which can be used for geotechnical design purposes.
• Soils are classified into groups according to size, and the groups are further divided into coarse, medium and fine sub-groups. The grain-size range is used as the basis for grouping soil particles into boulder, cobble, gravel, sand, silt or clay.
• Soil is classified into four types:
i. Sandy soil.
ii. Silt Soil.
iii. Clay Soil.
iv. Loamy Soil.
Identification of soil is the first and most important step in soil investigation for engineering works. It is the determination of soil-type through which crucial information about the soil properties can be obtained.
• This method determines the amount of soil material finer than the 75 μm (No. 200) sieve.

• The values given in parentheses (if provided) are not standard and may not be exact mathematical conversions. Use each system of units separately. Combining values from the two systems may result in nonconformance with the standard.
• There are two methods generally used to find the particle-size distribution of soil: (1) sieve analysis - for particle sizes larger than 0.075 mm in diameter, and (2) hydrometer analysis - for particle sizes smaller than 0.075 mm in diameter.
• Particle size distribution, also known as gradation, refers to the proportions by dry mass of a soil distributed over specified particle-size ranges.
• The moisture content when the groove closes for 1/2in after 25 drops of the cup is defined as the Liquid Limit. The test methods used are ASTM D4318 and AASHTO T 89. Plastic Limit is determined by repeatedly remolding a small ball of moist plastic soil and manually rolling it out into a 1/8in thread. The plasticity index of a soil is the numerical difference between its liquid limit and its plastic limit, and is a dimensionless number. Both the liquid and plastic limits are moisture contents.
• Shear strength is a term used in soil mechanics to describe the magnitude of the shear stress that a soil can sustain.
• Unconfined Compressive Strength (UCS) stands for the maximum axial compressive stress that a cohesive soil specimen can bear under zero confining stress. Unconfined compression test is one of the fastest and cheapest methods of measuring shear strength of soil.
• Uniaxial compressive strength (UCS) is one of the most important mechanical properties of rocks widely used in different engineering related projects to evaluate the stability of structures against loads. ... These models are easy to use but need calibrations by basic mechanical tests
• The Specific Gravity is computed as the ratio of the weight in air of a given volume of soil particles at a stated temperature to the weight in air of an equal volume of distilled water at the same temperature.
• Specific gravity is a fundamental property of soils and other construction materials. This dimensionless unit is the ratio of material density to the density of water and is used to calculate soil density, void ratio, saturation, and other soil properties.
• Soil consolidation refers to the mechanical process by which soil changes volume gradually in response to a change in pressure. This happens because soil is a two-phase material, comprising soil grains and pore fluid, usually groundwater.