Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Option A is correct.

Clay type and content influence strength through their role in cohesion. As water content increases " cohesion decreases. This is because increasing water content causes greater separation of clay particles (and thus easier slippage) and further, causes softening of soil cements.

Both A and C are correct.

Both options are indeed correct, but the statement that cohesion is more in well-compacted clays is more accurate.

Cohesion refers to the internal molecular attraction or bonding between soil particles. It is one of the factors that contribute to the strength and stability of soils. The cohesion of soil is influenced by several factors, including moisture content and soil composition.

Option A states that cohesion decreases as the moisture content increases. This statement is generally true because as the moisture content increases, the water fills the voids between soil particles, reducing the contact and interparticle forces.

This reduces the cohesive forces between the soil particles, leading to a decrease in cohesion. However, it is important to note that this relationship is not linear and can vary depending on the specific soil type and its characteristics.

Option C states that cohesion is more in well-compacted clays. This statement is also true. Well-compacted clays have a higher degree of compaction, meaning the soil particles are tightly packed together.

This dense arrangement leads to stronger interparticle forces and, consequently, greater cohesion between the soil particles.

In summary, while both options are correct, the statement that cohesion is more in well-compacted clays is more accurate because well-compacted clays typically exhibit higher cohesion due to their denser structure.

So, C is the correct answer.