Important Terms in Geo Technical Engineering (Soil mechanics)
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Important Terms in Geo Technical Engineering
(Soil mechanics)
Void Ratio
The void ratio of a
mixture is the ratio of the
volume of voids to volume of solids. The amount of void
present in the soil mass.
Porosity
The space between particles is called pore space. a soil has. The porosity of a soil is expressed as a percentage of the total volume of
the soil material.
Degree
of Saturation
The degree of saturation is the ratio of the volume of water to the volume of
voids. It is denoted by 'S'. The degree of saturation generally expressed as a percentage. It is equal to zero
when the soil is
absolutely dry and 100% when the soil is fully saturated.
Specific
Gravity
It also called relative density is the ratio of the density of a substance to the density of a reference
substance; equivalently, it is the ratio of the mass of a substance to the
mass of a reference substance for the same given volume.
Unit
Weight of Soil
Unit weight of the soil is the total weight of the soil divided by total volume. Total weight of soil also
includes weight of water.
Seepage
velocity
Seepage velocity is the velocity of groundwater calculated from Darcy's law. Seepage velocity is not the
actual velocity of the
water in the pores, but the apparent velocity through the
bulk of the porous medium.
Discharge
Velocity
Discharge velocity is the
volume of water flowing in unit time across the unit cross section
perpendicular to the direction of flow. Seepage flow is the volume of of
water flowing in unit time across the unit surface area of available voids
Flow
net
A flow net is a
graphical representation of two-dimensional steady-state groundwater flow through aquifers. Construction of a flow net is often used for solving groundwater flow problems where the geometry makes analytical
solutions impractical.
Moisture
content
Moisture content is the
amount of moisture in the sample given as a percentage of the sample's
original (wet) weight. Dry content is the
amount of solids which are left after drying given as a percentage of the
sample's original (wet) weight.
Liquid
limit
It
is the minimum water content the soil still act as liquid and it has some
shearing resistance to flow. The water content the soil is change liquid
limit to plastic limit is called liquid limit
Plastic
Limit
Plastic limit is the
water content in clay soil below Which it stops to behave like a plastic material. it starts to crumble when rolled in threads
of 3 mm diameter
Shrinkage
limit
It
is the minimum water content the reduction in water in soil does not make any
volume change is called shrinkage limit. The shrinkage limit is the
water content at which the volume of the soil starts to increase. It is also
at the point where the soil is 100% saturated.
Angle
of internal friction
Angle of internal friction (friction angle) A measure of
the ability of a unit of rock or soil to withstand a shear stress. It is the angle (φ), measured between the normal force (N) and
resultant force (R), that is attained when failure just occurs in response to
a shearing stress (S)
Specific
area
Specific surface area (SSA) is a property of solids defined as the total
surface area of a material per unit of mass, (with units of m2/kg or m2/g) or solid or
bulk volume (units of m2/m3 or m−1). It is a
physical value that can be used to determine the type and properties of a
material
Liquefaction
Liquefaction is a
phenomenon in which the strength and stiffness of a soil is reduced by
earthquake shaking or other rapid loading. Liquefaction and related phenomena have been responsible for
tremendous amounts of damage in historical earthquakes around the world
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