specific weight

Specific weight

The unit weight of a soil when void spaces of the soil contain both water and air. $${\displaystyle \gamma ={\frac {(1+w)G_{s}\gamma _{w}}{1+e}}}$$ where

γ is the moist unit weight of the material
γ_w is the unit weight of water
w is the moisture content of the material
G_s is the specific gravity of the solid
e is the void ratio

The unit weight of a soil when all void spaces of the soil are completely filled with air, with no water. The formula for dry unit weight is: $${\displaystyle \gamma _{d}={\frac {G_{s}\gamma _{w}}{1+e}}={\frac {\gamma }{1+w}}}$$ where

γ is the moist unit weight of the material
γ_d is the dry unit weight of the material
γ_w is the unit weight of water
w is the moisture content of the material
G_s is the specific gravity of the solid
e is the void ratio

The unit weight of a soil when all void spaces of the soil are completely filled with water, with no air. The formula for saturated unit weight is: $${\displaystyle \gamma _{s}={\frac {(G_{s}+e)\gamma _{w}}{1+e}}}$$ where

γ_s is the saturated unit weight of the material
γ_w is the unit weight of water
G_s is the specific gravity of the solid
e is the void ratio^[3]

The difference between the saturated unit weight and the unit weight of water.^[4] It is often used in the calculation of the effective stress in a soil. The formula for submerged unit weight is: $${\displaystyle \gamma '=\gamma _{s}-\gamma _{w}}$$ where

γ′ is the submerged unit weight of the material
γ_s is the saturated unit weight of the material
γ_w is the unit weight of water

The specific weight, also known as the unit weight (symbol γ, the Greek letter gamma), is a volume-specific quantity defined as the weight W divided by the volume V of a material: $${\displaystyle \gamma =W/V}$$ Equivalently, it may also be formulated as the product of density, ρ, and gravity acceleration, g: $${\displaystyle \gamma =\rho \,g}$$ Its unit of measurement in the International System of Units (SI) is newton per cubic metre (N/m³), with base units of kg ⋅ m^-2 ⋅ s^-2. A commonly used value is the specific weight of water on Earth at 4 °C (39 °F), which is 9.807 kilonewtons per cubic metre or 62.43 pounds-force per cubic foot.^[1]
The density of a material is defined as mass divided by volume, typically expressed in units of kg/m³. Unlike density, specific weight is not a fixed property of a material, as it depends on the value of the gravitational acceleration, which varies with location (e.g., Earth's gravity). For simplicity, the standard gravity (a constant) is often assumed, usually taken as 9.81 m/s².
Pressure may also affect values, depending upon the bulk modulus of the material, but generally, at moderate pressures, has a less significant effect than the other factors.^[2]
In fluid mechanics, specific weight represents the force exerted by gravity on a unit volume of a fluid. For this reason, units are expressed as force per unit volume (e.g., N/m³ or lbf/ft³). Specific weight can be used as a characteristic property of a fluid.^[2]
Specific weight is often used as a property of soil to solve earthwork problems.
In soil mechanics, specific weight may refer to:
Specific weight can be used in civil engineering and mechanical engineering to determine the weight of a structure designed to carry certain loads while remaining intact and remaining within limits regarding deformation.

^ National Council of Examiners for Engineering and Surveying (2005). Fundamentals of Engineering Supplied-Reference Handbook (7th ed.). ISBN 1-932613-00-5.

^ ^{a b c d e f} Finnemore, J. E. (2002). Fluid Mechanics with Engineering Applications. New York: McGraw-Hill. ISBN 0-07-243202-0.

^ Das, Braja M. (2007). Principles of Geotechnical Engineering. Canada: Chris Carson. ISBN 0-495-07316-4.

^ The Transtec Group, Inc. (2012). Basic Definitions and Terminology of Soils. [1] (Page viewed December 7, 2012

Wikipediarekin konexio arazoren bat gertatu da:

Wikipediako bilaketara joan