SOIL TESTING EQUIPMENT

Soil is a natural mixture of minerals, organic materials, air, and water. In construction, soil plays a critical role at the foundation of buildings and other infrastructure, providing support, load-bearing capacity, and drainage properties to the construction site.

There are different types of soils depending on their composition and particle size, including:

• Sand: a granular material composed of small rock and mineral particles with a larger particle size compared to silt and clay. Sand is often used in construction to prepare concrete and mortar mixes. It has excellent drainage properties and stability, provides good support, and helps prevent settling.
• Silt: a fine-grained soil particle that is smaller than sand but larger than clay. It has moderate fertility and good water retention and can contribute to the cohesion and workability of soil, making it suitable for certain types of foundations and backfilling.
• Clay: a very fine-grained soil particle with high plasticity and cohesion. It retains water well and can be easily molded when wet. In construction, clay can be used to create barriers that control seepage and as a base for structures like dams.
• Loam: a balanced mixture of sand, silt, and clay. Loam is often used for topsoil in landscaping and gardening projects, but it can also be suitable for certain construction applications due to its well-balanced properties.

Soil testing before construction provides engineers with essential data about the soil conditions of the job site before breaking ground, ensuring overall structural integrity. Soil testing includes:

• Soil Sampling: The process of collecting representative soil samples for soil testing analysis.
• Soil Penetration Testing: determines the resistance of soil to penetration or drilling to provide valuable information about the subsurface soil conditions, including strength, density and permeability.
• Classification Testing: classifies soils based on their particle size distribution and properties. The most common classification system is the Unified Soil Classification System (USCS), which categorizes soils into groups such as sand, silt, clay, and various combinations.
• Compaction Testing: measures the soil's density and moisture content to achieve the desired compaction levels for stability and load-bearing capacity.
• Consolidation Testing: assesses how soils settle under load, providing important information for designing foundations to minimize settlement.
• Swell Testing: evaluates the potential volume increase (swelling) of soils when they absorb water.
• Shear Testing: measures a soil's resistance to deformation or failure under applied forces.
• Permeability Testing: assesses the ability of soil to transmit water. It involves measuring the rate at which water passes through a soil sample under controlled conditions, providing information about drainage characteristics and potential groundwater movement.
• Resistivity Testing: involves measuring the electrical resistivity of soil to understand subsurface conditions, including the presence of contaminants or variations in soil composition.
• California Bearing Ratio (CBR) Testing: evaluates the strength of a soil when supporting loads. It is commonly used in pavement design to assess the load-bearing capacity of subgrade soils.
• Triaxial Testing: assesses the shear strength and stress-strain characteristics of soils under different confining pressures.
• Vane Shear Testing: measures the shear strength of cohesive soils in the field. It involves inserting a vane into the soil and measuring the torque required to shear the soil.

Soil testing supplies, equipment and accessories to collect, prepare, and analyze soil samples. Forney stocks a wide variety of soil testing supplies that satisfy ASTM, AASHTO and ISO standards, including but not limited to:

• Soil processor: prepares soil samples for moisture/density (Proctor) tests.
• Soil grinder: crushes and grinds soil samples to a consistent particle size for various geotechnical tests.
• Soil trimmer: trims and shapes soil specimens for laboratory testing.
• Shelby tube ejector: a hydraulically driven tool designed to rapidly eject three-inch samples from 30-inch-long, thin-wall sample tubes. It also includes a sample trough to collect and support the ejected soil samples.
• Soil penetrometer: an instrument used to measure the resistance of soil to penetration, providing an indication of soil strength.
• Proctor test set: used in the laboratory to determine the optimum moisture content and maximum dry unit weight from a representative soil sample taken from the construction site. Includes a compaction hammer, mold, straight edge, stainless steel spoon, soil preparation knife, sample ejector, moisture box, wash bottle, material pan, compact balance, and quincy bench oven.
• Vacuum degassing oven: used to remove air and gas from soil samples.
• Auger: a drilling tool with a helical screw blade that is used for boring holes in soil or other materials.
• Expansion index consolidometer: performs expansion tests of cured soil specimens. Specimen is placed in unit with air-dried porous stones and loaded with a stainless steel weight for 10 minutes, then immersed in distilled water for 24 hours. Height is recorded to determine maximum swell.
• Torvane shear test set: Measures shear strength of cohesive soils in the laboratory or field.
• Triaxial test chamber: applies stress along multiple axes from the parallel platens that bookend the specimen. When the sample fails, the machine collects data regarding the sample’s stress and strain characteristics. This data can be used to determine how stable soil is for construction purposes and figure out whether it will collapse or support the structure.
• Resistivity meter: used to measure the electrical resistivity of soils, which can provide information about soil moisture content and salinity.
• Swell consolidation machine: used to perform tests on 2 in (50.8mm) and 2.5 in soil samples. The stainless steel ball bearing and load disk distribute a vertical load evenly to sample, and the dial indicator is aligned above to measure changes due to swell or consolidation.
• Compaction permeameters: utilizes standard 4.0 in (101.6 mm) compaction mold 1/30 ft³ (0.94 L) or 6.0 in (152.4 mm) compaction mold for performing falling or constant head tests.
• Relative density testing apparatus: used to determine the relative density of cohesionless free-draining soils by using vibratory compaction and pouring funnels to obtain minimum index density.
• Unconfined compression accessories: Accessories used with a load frame to determine the unconfined compressive strength of a cohesive soil sample.

Forney also offers soil test equipment and apparatus options for California Bearing Ratio (CBR), unconfined compression (UC), triaxial, Marshall, and soil cement tests, providing everything you need for a wide variety of soil evaluations.

Soil testing is an integral part of construction materials testing, ensuring the safety of the foundation of a structure. Here are some other helpful resources related to soil testing and equipment:

• Construction Materials Testing Protocols [Full Listing]

• Glossary of Construction Materials Testing Terms

• Concrete Testing Equipment Essentials: 6 Categories