asbogstudy11

the line on the plasticity chart that divides clays from silts. Equations of the line is horiztontal at PI=4 to LL=25.5, then PI=0.73 (LL-20)

water content at the boundaries between the states of consistency of a soil

the load per unit area whihc the ground ca safely support without excessive yield

The density of a material measured in mass per unit volume

a modulus of elasticity which relates a change in volume to the hydrostatic state of stress.; It is the reciprocal of compressibiltiy

a measure of the curvature of the grain size distribution plot. Well-graded sands and gravels have coefficients of curvature between 1 and 3

A measure of the grain size uniformity using the ratio of particle sizes D₆₀ to D₁₀.

the process of increasin the density of a soil (usually fill) by rolling, tamping, vibrating or other mechanical means

the degree of adhesion between soil particles that can resist deformation or rupture

Gradual or slow reduction in volume and increas in density of a soil mass in response to increased load or compressive stress

the final void ratio at ultimate strength achieved by loose and dense samples of the same soil after shearing

the raito of the volume of water to the total volume of void space. The value of SR can range from 0 (0%) to 1 (100%)

an increase in the bulk volume during deformation, caused by a change from a close-packed structure to an open-packed structure

a laboratory test to measure the shear strength of a soil

The density of a soil when it is completely dry; bulk density divided by 1 + water content

The strength of a soil when dry as determinded by the crushing test

The diameter D₁₀ which corresponds to the precentages, by weight, of grains equal to 10% of the grain-size diagram. Ten percent of the particles are finer and 90% are coarser than the effective size

That part of the total stress that is due entirely to the solid particles of soil, and represents an excess over the neutral stress or pore-water pressure. Effective stress = total stress minus pore-water pressure

a soil in which some particle sizes are missing

a statement of elastic deformation - the strain is linearly proportional to the applied stress

the upper limit of the plastic state. Water content, in percent of dry weight, at which two sections of a pat of soil, separated by a specific distance, barely touch each other but do not flow together when given a sharp blow

The sudden large decrease in shearing resistance of a cohesionless soil, caused by a collapes of the structure by shock or strain, and associated with a sudden but temporary increase of the pore-water pressure. The material is transformed into a fluid mass

graphical representation of the state of stress (normal and shear) on a particular plane inclined at an angle ot the major principal stress

an equation describing the failure of a material in shear fracture. The rupture line is a Mohr circle can be approximated by this equation

the component of stress that acts perpendicular to the plane

the moisture content at which the maximum dry density of a soil is attained

erosion by percolating waters or seepage in a layer of subsoil resulting in caving and the formation of tunnels or pips through which the soluble or granular material is removed

range in water content between the liquid limit (LL) and the plastic limit (PL). PI=LL-PL

the lower limit of the plastic state. Water content at which the soil begins to crumble when rolled out onto thin threads

An elastic constant (does not exceed 0.5). The ratio of the lateral unit strain to the longitudinal unit strain in a body that has been stressed longitudinally within it's elastic limit

The percentage of the bulk volume of rock or soil that is occumpied by void space

the condition of a soil in which a decrease in intergranular pressure allows water to flow upward with sufficient velocity to reduce significantly the soil's bearing capacity

the raito of the difference between the void ratio of a cohesionless soil in the loosest state and any given void ratio to the difference between its void ratios in the loosest and in the densest states

• e_max - e = R.D.
• e_max - e_min

the amount of compaction relative to the moisture-density curve, or compaction curve

the movement of water or other fluid through a porous material such as soil

the gradual downward movement of an engineered structure due to compression of the soil below the foundation

a modulus of elasticity in shear. It measures the shear strain resulting from shear stress on a plane

the internal resistance of a soil to shear stress consisting of a combination of friction and cohesion

the component of stress that acts along a plane through any point in the body

Water content at which the soil volume is lowest

the raito of the density of the solid particles to the density of water at 4^oC

the property of a soil that is able to absorb strees by plastic deformation

the most widely used shear strength test in which drainage conditions can be controlled. Three principal types of tests are: unconsolidated-undrained (UU), consolidated-undrained (CU), and consolidated-drained (CD)

a special case of the triaxial test in which axial stress is applied to a specimen under atmospheric pressure to obtain the value of the shear strength

the line on the plasticity chart that marks the approximate uppper limit of the relationship between the plasticity index and the liquid limit for natural soils. It is a check agains erroneous data - if a data point plots above or to the left of the line, verify the information

The weight of soil plus water per unit volume

the ratio of the volume of void space to the volume of solids

a soil with all grain sizes present with no excess in any size range. Equivalent to the geologist's term "poorly sorted"

an elastic constant given by the ratio of stress to it's corresponding strain under given conditions of load, for materials that deform elastically according to Hooke's Law