GEOTECHENG
The study of physical properties and behavior of soil under different conditions. This branch of civil engineering is essential for understanding how soils will respond to different loads, how they wwill consolidate over time, and how they can be effectively compacted
Soil Mechanics
Refers to the ability of soil or rock to allow fluids to pass through its pores or fractures. It's a crucial property for understanding groundwater flow
Permeability
A type of soil composed of both silt and clay particles. This mixture often exhibits characteristics from both soil types, affecting its plasticity and permeability
Silty Clay
The process of increasing the density of soil by mechanically pressing it to reduce air gaps. Proper compaction is vital in construction to ensure soil stability and strength
Compaction
The process by which soils decrease in volume over time under sustained load, primarily due to the expulsion of water from pore spaces. This affects settlement rates and must be considered in design
Consolidation
The maximum load per unit area that the ground can support without excessive settlement. Ensuring adequate bearing capacity is essential for the stability of structures
Bearing Capacity
The ratio of the volume of voids to the volume of solids in a soil sample
Void Ratio
The percentage of water present in the soil compared to its dry weight
Moisture Content
The range of water content where soil exhibits plastic properties, found by subtracting the plastic limit from the liquid limit
Plasticity Index
The water content at which further moisture loss does not cause additional volume reduction
Shrinkage Limit
The tendency of soil to increase in volume when it absorbs water, critical for soils
like clays
Swell Potential
Understanding the properties of soil through testing is essential for predicting how it will behave under different conditions. These tests help engineers determine the best methods for soil compaction, foundation design, and more
Soil Testing and Properties
A laboratory test to find the optimum moisture content at which soil can be compacted to its maximum density. This test is crucial for construction projects requiring stable soil foundations
Proctor Test
The proportion of different-sized particles in a soil sample, usually determined through sieve analysis for coarse soils and hydrometer analysis for fine soils. It significantly impacts soil's engineering properties like permeability and shear strength
Grain Size Distribution
The soil's resistance to shearing forces, which cause layers to slide past one another. It is a key factor in assessing soil stability
Shear Strength
A test to determine the size distribution of fine-grained soils by measuring their settling velocity in water
Hydrometer Analysis
A graph that shows the relationship between water content and dry density of soil. It helps identify the optimum moisture content for maximum soil compaction
Compaction Curve
The water content at which soil begins to behave plastically, meaning it can be deformed without cracking
Plastic Limit
The water content at which soil transitions from a plastic state to a liquid state
Liquid Limit
The water content boundaries that define the different states of consistency for fine-grained soils (solid, plastic, liquid)
Atterberg Limits
A test that evaluates the strength of subgrade soil and its ability to support road and pavement structures
California Bearing Ratio (CBR)
A test that measures the mechanical properties of soil, including its strength and cohesion, under different conditions
Triaxial Test
Fluid flow through soils, particularly in terms of groundwater movement, is a critical aspect of geotechnical engineering. The principles of fluid mechanics are used to analyze and predict how water will move through soil
Fluid Flow and Hydraulics
Describes the flow of fluid through a porous medium, where flow rate is proportional to the pressure gradient. It is fundamental to understanding groundwater flow
Darcy's Law
The movement of water through soil, which can occur in any direction and is often analyzed using flow nets to prevent soil erosion or failure in structures like dams
Seepage
Fluid movement in parallel layers, with minimal mixing between the layers. This type of flow is typical in slow-moving, viscous fluids
Laminar Flow
A fluid flow regime characterized by chaotic, irregular motion, often resulting in greater energy loss and mixing
Turbulent Flow
The volume of fluid passing through a given area per unit time. It’s a key parameter in designing systems like drainage and irrigation
Flow Rate
The ability of an aquifer to transmit water horizontally, depending on the permeability of the material and the thickness of the aquifer
Transmissivity
An empirical equation used to estimate the hydraulic conductivity of soils, particularly sands, based on grain size distribution
Hazen’s Formula
Relates the permeability of a porous medium to its porosity and the specific surface area of the particles
Kozeny-Carman Equation
A graphical tool used to represent the flow of water through soils, showing both flow lines (paths of water particles) and equipotential lines (lines of constant hydraulic head)
Flow Net
The stress carried by the soil skeleton, calculated by subtracting pore water pressure from total stress. It’s crucial for understanding soil strength and stability
Effective Stress
These methods and materials are used in the construction and maintenance of soil and rock structures, ensuring that they are stable, durable, and able to withstand environmental stresses
Geotechnical Engineering Methods
The controlled use of explosives to break up rock or soil, commonly used in mining and construction to create foundations or tunnels
Blasting
Material used to refill an excavation, usually to support a structure or restore the original ground level. The choice of backfill material affects the stability of the structure
Backfill
A ground improvement technique that densifies loose, granular soils by using a vibrating probe. It increases soil strength and decreases settlement
Vibroflotation
A permeable fabric used in civil engineering to improve soil stability, control erosion, and aid in drainage. Geotextiles are often used in road construction, retaining walls, and landfills
Geotextile
Layers of sedimentary rock or soil with consistent characteristics that distinguish them from layers above or below. Understanding the strata is crucial for foundation design
Strata
A field test used to determine the relative density and shear
strength of soil. It involves driving a sampler into the ground at the bottom of a borehole and measuring the resistance
Standard Penetration Test (SPT)
A phenomenon where saturated soil temporarily loses its strength and behaves like a liquid, typically triggered by seismic activity
Soil Liquefaction
A synthetic material used to reinforce soils, particularly in retaining walls and roadbeds. It improves the mechanical properties of the soil
Geogrid
The pressure exerted by water within the soil pores, affecting the soil's effective stress and overall stability
Pore Water Pressure
The total load per unit area applied to a soil mass, including both the weight of the soil particles and the water within the pores
Total Stress
These equations are the backbone of civil and geotechnical engineering, providing the mathematical framework for analyzing fluid flow, soil mechanics, and structural stability
Fundamental Engineering Equations
A principle of fluid dynamics that describes the conservation of energy in a flowing fluid, combining kinetic energy, potential energy, and fluid pressure
Bernoulli’s Equation
Governs the flow of fluid through porous media, stating that the flow rate is proportional to the pressure gradient and inversely proportional to the fluid’s viscosity
Darcy’s Law
A procedure used to determine the liquid limit of soils, which helps classify soil types and predict their behavior under load
Casagrande Method
States that the mass flow rate must remain constant from one cross-section of a fluid flow system to another, fundamental in fluid dynamics
Continuity Equation
A dimensionless number used to predict flow patterns in fluid dynamics, distinguishing between laminar and turbulent flow
Reynolds Number
Used to estimate the velocity of flow in open channels, considering factors like channel shape, roughness, and slope
Manning’s Equation
Describes the settling velocities of small spherical particles in a fluid, which is critical in sedimentation analysis
Stokes' Law
A set of nonlinear partial differential equations that describe the motion of viscous fluid substances, including both liquids and gases
Navier-Stokes Equations