GEOTECH 3: Stresses of Soil and Soil Settlement

It is the stress resulting from particle-to-partcile contact of soil

Effective Stress

Effective Stress Formula

It is the stress induced by water pressure

Pore Water Pressure

Pore Water Pressure Formula

True of False: The effective stress increases as the water table lowers

Trulalu

The ratio, expressed as a percentage, of the amount of consolidation at a given time within a spil mass, to the total amount of consolidation obtainable under a given stress condition

Degree of Consolidation

Degree of Consolidation Formula in terms of settlement

Degree of Consolidation in terms of pore water pressure

It is the parameter used to describe the rate at which saturated clay or other soil undergoes consolidation or compactiom, when subjected to an increase in pressure

Coefficient of Consolidation, Cv

It is the volume decrease of a unit volume of soil per unit increase of effective pressure during compressiong

Coefficient of Volume Compressibility, m

It is the slope of the void ratio-pressure curve when both are plotted on an arithmetic scale

Coefficient of Compressibility

It is the parameter used to find the consolidation coefficient with tome taken for consolidation settlement in soil. It is a non-dimensiomal number

Time factor, Tv

Coefficient of Consolidation Formula

Coefficient of Volume Compressibility

Coefficient of Compressibility

Time Factor Formula

Singlr Drainage: Hdr = H

Drained both sides: Hdr= H/2

Time Factor Formula in terms of degree of consolidation

Height of capillary rise

Pore water Pressure in Capillary Rise

h= height measured from the water level

It is the instantaneous process of reducing the volume voids due to expulsion of pore air

Compaction

It is a time dependent process of reducing the volume of voids due to expulsion of pore water and plastic readjustment of soil solids

Consolidation

Deformation of soil due to vertical stress

Settlement

If is defined as the vertical movement of the ground due to increased vertical stresses are applied to the ground surface

Settlement

It is caused by the elastic deformation of dry, moist, and saturated soils without any change in moisture content

Immediate Settlement

It is caused by a volume change in saturated cohesive soils due to explulsion/removal of water that occupies the void spaces

Primary consolidation settlement

It is caused by plastic readjustment of soil fabrics. It is an additional form of compression that occurs at constant effective stress

Secondary Consolidation Settlement

Primary consolidation Settlement Formula

Primary Consolidation Settlement of Normally Consolidated Clay

H-thickness of clay layer

Pc- preconsolidation pressure

Po - present overburden pressure

∆P - additional load

Primary Consolidation Settlement of Overconsolidated Clay

H-thickness of clay layer

Pc- preconsolidation pressure

Po - present overburden pressure

∆P - additional load

Swell Index Formula

Compression Index

Approximate Slope method in getting ∆P

Immediate Settlement Formula

Secondary Consolidation Settlement Formula

Total Settlement

Pressure head sa soil

Overconsolidated Ratio in terms of pressur

OCR = Pc/Po