Soil Mechanics And Foundation MCQ Questions & Answers | Civil Engineering

Effective stress: It is the stress transmitted through soil particles at their points of contact. This is critical in understanding the behavior of soils under load.

A physical parameter that can be measured: Effective stress is a measurable quantity calculated as the total stress minus pore water pressure.

Importance: Effective stress is a key parameter because it governs the engineering properties of soil, such as shear strength, compressibility, and permeability.

Since all the statements are correct, Option D: all of the above is the correct answer.

According to Atterberg, the soil is said to be of medium plasticity if the plasticity index (PI) is

7 < PI < 17.

The plasticity index (PI) is a measure of the plasticity of a soil and is calculated as the difference between the liquid limit (LL) and the plastic limit (PL).

Soils with a PI between 7 and 17 are considered to have medium plasticity. This range indicates moderate changes in consistency with changes in moisture content.

Therefore, the correct option is 7 < PI < 17.

Sand particles are made of rock minerals.

Sand primarily consists of small fragments of weathered rock and minerals, predominantly quartz, which is a durable and resistant mineral.

Kaolinite, illite, and montmorillonite are types of clay minerals, which are much finer in particle size compared to sand and have different properties and compositions.

Therefore, the correct answer is that sand particles are composed of rock minerals.

The coefficient of consolidation of a soil is affected by both compressibility and permeability.

The coefficient of consolidation (C_v​) is a measure used in soil mechanics to describe how fast a soil consolidates under load.

Compressibility influences how much volume change occurs in the soil when a load is applied.

Permeability determines the rate at which water can flow through the soil pores, affecting how quickly excess pore water pressure dissipates.

Therefore, the coefficient of consolidation is dependent on both these properties, making Option C the correct answer.