Soil shear strength is characterized by what factors?

• A. The weight of the soil and moisture content
• B. Frictional resistance and cohesion
• C. Plasticity and compressibility
• D. Soil color and structure

Answer: (B)

Soil shear strength is primarily determined by frictional resistance and cohesion, which are the two critical components contributing to the overall strength of the soil. Frictional resistance arises from the inter-particle friction between the soil grains, which helps to stabilize the soil when it is subjected to shearing forces. Cohesion refers to the attractive forces between soil particles, particularly in fine-grained soils like clay, which also contribute to the soil's ability to hold together and resist deformation.

In contrast, the other factors listed do not directly relate to shear strength. The weight of the soil and moisture content can influence shear strength indirectly, but they are not considered the defining characteristics of shear strength itself. Plasticity and compressibility focus on the deformation properties of soil under stress rather than its resistive capacity. Soil color and structure may provide insights into soil type and behavior but do not specifically characterize shear strength. Thus, frictional resistance and cohesion are the fundamental factors that define the shear strength of soil.