HPGE: Terminologies

Soil that contains silt and clay.

Cohesive Soil

Soil that consists of gravel, sand, and stone.

Cohesionless Soil

A deep groundwater deposit where underground water is available for supply and irrigation.

Well

The upper surface of underground water in an aquifer.

Water Table

Underground layers of water-bearing rock that can yield water.

Aquifers

The level below which the soil or rock is saturated with water.

Phreatic Table

Fluid flow where the fluid travels parallel to adjacent layers and the paths of individual particles do not cross.

Laminar Flow

A condition of flow characterized by irregular paths of fluid particles, causing momentum exchange.

Turbulent Flow

A principle stating that the increase in kinetic energy per unit weight is equal to the decrease in potential energy per unit weight.

Bernoulli Principle

The theoretical velocity of a jet of liquid issuing from an orifice under a head of height h.

Torricelli Law

The line representing the total potential energy of the fluid in a system.

Hydraulic Grade Line

A type of open channel flow where the Froude Number is equal to 1.

Critical Flow

Flow in a conduit with a free surface subjected to atmospheric pressure.

Open Channel Flow

An overflow structure built across an open channel for measuring or controlling flow.

Weir

A test used to determine the grain size distribution of soils passing the No. 200 sieve.

Hydrometer Analysis

The grain size corresponding to 10 percent passing on a grain-size distribution curve.

Hazen's Effective Size

The ratio of the difference between the void ratios of a cohesionless soil in its loosest and existing natural state.

Relative Density

Describes the degree and kind of cohesion and adhesion between soil particles related to resistance to deformation.

Soil Consistency

A field measure of the ability of soil to withstand applied stress using the thumb and forefinger.

Fingering Resistance

The attraction of one water molecule to another due to hydrogen bonding.

Cohesion

The attraction of a water molecule to a non-water molecule.

Adhesion

The capacity of soil to adhere to other objects, estimated at moisture content displaying maximum adherence.

Stickiness

The moisture content at which soil begins to behave as a plastic material.

Plastic Limit

The moisture content at which soil begins to behave as a liquid material and starts to flow.

Liquid Limit

The densification of soil by removal of air, requiring mechanical energy.

Compaction

The moisture content at which the maximum dry unit weight of soil is attained.

Optimum Moisture Content

A line along which water particles travel from upstream to downstream in permeable soil.

Flow Line

A line along which the potential head at all points is equal.

Equipotential Line

The sum of the vertical components of forces at the points of contact of solid particles per unit area.

Total Stress

Settlement caused by elastic deformation of dry soil and moist and saturated soils without moisture change.

Immediate Settlement

Settlement resulting from volume change in saturated cohesive soils due to expulsion of water.

Primary Consolidation Settlement

The internal resistance per unit area of the soil mass to resist failure and sliding along any plane.

Shear Strength

The ratio of preconsolidation pressure to present effective overburden pressure.

Overconsolidation Ratio (OCR)

The process of identifying layers of deposits that underlie a proposed structure and their physical characteristics.

Geotechnical Exploration

A technique used in geotechnical engineering to analyze the stability of slopes by dividing the slope into slices and evaluating the forces acting on each slice.

Method of Slices

A method used to analyze the stability of slopes that simplifies the calculation of forces acting on each slice by assuming a circular failure surface.

Bishop's Simplified Method of Slices

A method for analyzing slope stability that considers the equilibrium of forces acting on a slice of soil.

Sarma Method

A method used in slope stability analysis that incorporates the effects of pore water pressure and soil properties.

Lorimer's Method

A type of failure in which the surface of sliding occurs below the toe of the slope.

Slope Failure

A type of failure that occurs when the sliding surface is at the base of the slope.

Base Failure

A type of slope failure characterized by a circular sliding surface.

Circular Failure

A type of failure that occurs when the sliding surface intersects the slope or is above its toe.

Critical Failure

The failure circle in slope stability that passes through the toe of the slope.

Toe Circle

A condition in which every point in a soil mass is on the verge of failure.

Plastic Equilibrium

The pressure that soil exerts against a structure in a sideways direction, important for the design of retaining walls and foundations.

Lateral Earth Pressure

The state of soil when it is allowed to relax or move outward to the point of reaching its limiting strength.

Active State

An enlargement of a load-bearing wall or column that spreads the load over a larger area of soil.

Spread Footing

A structural member that transmits the load of the superstructure to the lower layers of soil.

Footing

A type of foundation that covers the entire area under a structure, supporting multiple columns and walls.

Mat Foundation

An engineer known for presenting a theory for evaluating the ultimate bearing capacity of shallow foundations.

Rankine

An engineer who proposed a correlation for the net allowable bearing pressure for foundations based on standard penetration resistance.

Terzaghi

A type of retaining wall that relies on its own weight and the weight of the soil above for stability.

Gravity Retaining Wall

A retaining wall that is supported on one side and relies on its structure to resist lateral earth pressure.

Cantilever Retaining Wall

The ratio of the unconfined compression strength in an undisturbed state to that in a remolded state.

Degree Of Sensitivity

A method for determining the liquid limit of soil by measuring the penetration of a cone into the soil.

Fall Cone Test

The distance between the center of gravity of a floating body and its metacenter.

Metacentric Height

The resultant upward pressure of a fluid on a floating or immersed body, equal to the weight of the fluid displaced.

Buoyant Force

The state where the metacenter lies above the center of gravity, ensuring stability.

Equilibrium of a Floating Body

The principle stating that the upward buoyant force on a submerged object is equal to the weight of the fluid displaced by the object.

Archimedes' Principle

The center of mass of the displaced fluid, which plays a critical role in determining the stability of floating bodies.

Center of Buoyancy

The phenomenon where a fluid is displaced as a result of an object being submerged in it.

Displacement of fluid due to submerged body

The generation of force resulting from the movement of fluid or objects within the fluid.

Development of force due to dynamic action

Forces within a fluid that counteract external forces acting on it.

Internal shear forces mitigating external forces

The center of gravity of the volume of the liquid displaced by an immersed body.

What is the center of buoyancy?

Negligible; it is typically considered to be zero.

What is the horizontal component of buoyant force?

Through the centroid of the displaced volume of fluid.

Where does the line of action of the buoyant force act?

Center of buoyancy is located above the center of gravity of the displaced liquid.

What is the wrong statement regarding buoyant force?

A force equal to the weight of the fluid displaced by the body.

According to the principle of buoyancy, what will lift a body immersed in fluid?

By altering the shape of the object.

How can relatively denser objects float on less dense fluid?

Potential, kinetic, and pressure heads.

What does the energy gradient line (EGL) consider?

Potential, kinetic, and pressure heads.

What does the hydraulic gradient line (HGL) consider?

EGL always drops in the direction of flow.

What is true about the EGL?

HGL may or may not be above EGL.

What is true about the HGL?

Pressure head.

What does the vertical intercept between EGL and HGL represent?

The slope of HGL will be smaller than that of EGL.

How does the slope of HGL compare to EGL in a uniform pipe?

The principle of conservation of mass.

What principle is the equation of continuity based on?

The law of conservation of energy.

What does Bernoulli's equation deal with?

Energy.

What dimension do all terms of energy in Bernoulli's equation have?

Friction of surface, sudden enlargement or contraction of area, and obstructions.

What causes energy losses in pipes?

Friction.

What is the major loss of energy in long pipes due to?

Frictional loss.

What is a major loss in fluid flow?

Sudden enlargement, sudden contraction, and bends in the pipe.

What causes minor losses in fluid flow?

A substance that cannot remain at rest under action of any shear force.

What is a fluid?

4°C.

At what temperature is the density of water maximum?

Cohesion.

What is the property of a fluid where its own molecules are attracted to each other?

Adhesion.

What is the property of a fluid where molecules of different fluids are attracted to each other?

When it is at rest.

When is the normal stress in a fluid constant in all directions?

Because it contains dissolved salts.

Why is the specific weight of seawater greater than that of pure water?

Surface tension.

What causes a liquid's free surface to contract to the smallest possible area?

Atmospheric pressure.

What does a barometer measure?

Pressure in pipes, channels, etc.

What does a manometer measure?

It will be lower than the surface of the liquid.

What happens to the free level of fluid in a glass tube if cohesion is greater than adhesion?

It undergoes a volumetric change due to compressibility.

What occurs when a fluid is subjected to resistance?

Pascal's law.

What law states that liquids transmit pressure equally in all directions?

It may increase or decrease depending on the characteristics of the liquid.

What happens to the rise or depression of liquid in a tube due to surface tension with an increase in tube size?

Because its vapor pressure is so low that it may be neglected.

Why is mercury used in barometers?

The point through which the resultant pressure of the liquid acts on an immersed body.

What is the center of pressure?

The center of pressure is always below the centroid for a submerged plane.

What is the relationship between centroid and center of pressure?

When the area is horizontal.

When is the total pressure force on a plane area equal to the area multiplied by the intensity of pressure?

It is equal to the normal force on the vertical projection of the surface.

What is true about the horizontal component of hydrostatic force?