Geosynthetic Reinforced Soil (GRS) Walls

1Stresses and Shear Strength of Soils

In the design of earth structures, good knowledge of shear stiffness/strength of soil is of importance because excessive deformation or failure of earth structures may occur as a result of insufficient resistance to shear stress. This chapter presents a review of shear behavior and shear strength of soils that are relevant to the design of earth structures. We begin the chapter with an explanation of stress at a point, followed by a brief explanation of effective stress and Mohr–Coulomb failure criterion. We then discuss commonly used laboratory and field tests for evaluation of shear behavior and determination of the shear strength of soils. We conclude the chapter with a discussion of the design consideration of the shear strength for soils under different loading conditions.

1.1 Stress at a Point

In engineering analysis and design of structures, stress has been proven to be an extremely useful parameter to quantify the effects of internal and external influences on a structure. For earth structures, common influences include external loads, self‐weight of soil and water, seepage force, and temperature change. Stress in a body is commonly referred to a plane. Stress on a plane with cross‐sectional area A when subjected to a force system denoted F can be evaluated by a simple equation: . This equation, however, is useful only if the ...