Shear Strength of Soil

One of the most important and the most controversial engineering properties of soil is its shear strength or ability to resist sliding along internal surfaces within a mass. The stability of a cut, the slope of an earth dam, the foundations of structures, the natural slopes of hillsides and other structures built on soil depend upon the shearing resistance offered by the soil along the probable surfaces of slippage.

A knowledge of shear strength of soils is necessary to determine: – bearing capacity of foundation – lateral pressure on earth retaining structures – slope stability and

Soils consist of individual particles that can slide and roll relative to one another. •Shear strength of a soil is equal to the maximum value of shear stress that can be mobilized within a soil mass without failure taking place. •Soil failure usually occurs in the form of “shearing” along internal surface within the soil.

•Thus, structural strength is primarily a function of shear strength.