Foundation Engineering
Expert-defined terms from the Postgraduate Certificate in Geotechnical Engineering & Soil Mechanics course at London School of Planning and Management. Free to read, free to share, paired with a globally recognised certification pathway.
Active Earth Pressure #
The horizontal force exerted by soil on a retaining structure when the soil is moving away from the structure, such as during excavation.
Atterberg Limits #
A set of tests used to determine the critical water content of a soil, including the liquid limit, plastic limit, and shrinkage limit.
Bearing Capacity #
The maximum load that can be applied to the ground without causing shear failure.
Cohesion #
The attractive force between soil particles, resulting in the ability of the soil to stick together.
Consolidation #
The process of soil settlement due to the application of load, resulting in a decrease in volume and increase in density.
Darcy's Law #
A mathematical relationship used to describe the flow of fluids through porous media, including soil.
Effective Stress #
The portion of the total stress carried by the soil skeleton, calculated as the total stress minus the pore water pressure.
Factor of Safety #
The ratio of the ultimate bearing capacity of a soil to the applied load, used to ensure stability and safety.
Fill #
Soil or other materials placed in a controlled manner to raise the ground level or create a new surface.
Ground Improvement #
The modification of soil properties to improve its bearing capacity, reduce settlement, or increase stability.
In Situ Testing #
Testing performed in the ground without removing the soil, including standard penetration tests (SPT) and cone penetration tests (CPT).
Lateral Earth Pressure #
The horizontal force exerted by soil on a retaining structure, including active, passive, and at-rest earth pressure.
Liquefaction #
The loss of strength and stiffness of a soil due to the generation of excess pore water pressure during earthquakes or other dynamic loading.
Permeability #
The ability of a soil to allow the flow of water through its pore spaces, measured in units of Darcy.
Pore Water Pressure #
The pressure of water within the pore spaces of a soil, affecting the soil's strength and stability.
Proctor Test #
A laboratory test used to determine the maximum dry density and optimum moisture content of a soil for compaction.
Retaining Wall #
A structure designed to resist the lateral pressure of soil, including gravity walls, cantilever walls, and anchored walls.
Saturated Soil #
Soil in which all pore spaces are filled with water, resulting in no air bubbles.
Shear Strength #
The ability of a soil to resist shear forces, measured by its cohesion and angle of internal friction.
Settlement #
The vertical movement of soil or structures due to consolidation or other factors, affecting stability and serviceability.
Shrinkage Limit #
The water content below which a soil will not shrink upon drying.
Slake Durability Test #
A test used to determine the resistance of a soil to disintegration when exposed to water.
Soil Mechanics #
The study of the behavior of soils under various conditions, including loading, unloading, and environmental factors.
Standard Penetration Test (SPT) #
A in situ testing method used to determine the relative density and strength of a soil, based on the number of blows required to drive a standard penetration rod into the soil.
Swelling Potential #
The ability of a soil to increase in volume upon wetting, affecting stability and serviceability.
Total Stress #
The sum of the effective stress and pore water pressure, representing the total load on the soil.
Undrained Shear Strength #
The shear strength of a soil tested under conditions of zero drainage, used for short-term stability analysis.
Uniformity Coefficient #
A measure of the range of particle sizes in a soil, calculated as the ratio of the diameter of the largest particle to the diameter of the smallest particle.
Unsaturated Soil #
Soil in which some pore spaces are filled with air and some with water.
Vane Shear Test #
A laboratory or in situ testing method used to determine the undrained shear strength of a soil, based on the torque required to rotate a vane in the soil.
Water Table #
The level at which the groundwater is at atmospheric pressure.
Wellpoint System #
A groundwater control method used to lower the water table around an excavation, using a series of wellpoints connected to a vacuum source.