Adhesion

Definition

Adhesion is the tendency of dissimilar particles or surfaces to cling to one another, often influenced by molecular forces. This property plays a crucial role in how water interacts with soil particles, impacting soil suction and capillary action. In geotechnical contexts, adhesion affects water retention, soil stability, and the behavior of saturated soils under different conditions.

5 Must Know Facts For Your Next Test

1. Adhesion causes water molecules to cling to soil particles, which is essential for capillary rise in unsaturated soils.
2. The degree of adhesion varies with different types of soil particles; for example, clay has a higher adhesion due to its smaller size and larger surface area.
3. Soil suction is directly influenced by adhesion; higher adhesion leads to greater water retention and increased suction in the soil.
4. In geotechnical engineering, understanding adhesion helps predict how soil will behave under stress and in various moisture conditions.
5. Adhesion affects the effectiveness of soil additives and stabilization techniques, as it influences how well these materials interact with existing soil.

Review Questions

• How does adhesion contribute to the movement of water through soil?
  • Adhesion allows water molecules to stick to soil particles, which is essential for the process of capillarity. This sticking action helps pull water upwards through tiny pores in the soil against gravity. The stronger the adhesion between water and soil particles, the more effective the capillary action will be in moving moisture throughout the soil profile.
• Discuss the role of adhesion in influencing soil suction and its implications for agricultural practices.
  • Adhesion plays a significant role in determining soil suction, which affects how water is retained in the soil. High adhesion leads to increased suction, meaning that plants may have a harder time extracting moisture from the soil. Understanding this relationship helps farmers manage irrigation practices effectively, ensuring that crops receive adequate water without leading to over-saturation or drought stress.
• Evaluate how variations in adhesion between different soil types can impact construction projects and soil stabilization efforts.
  • Variations in adhesion between different soil types can significantly impact construction projects by influencing factors such as stability, drainage, and load-bearing capacity. For instance, clay soils exhibit high adhesion, which can result in greater moisture retention and increased risk of expansion or shrinkage. In contrast, sandy soils have lower adhesion, making them more prone to drainage issues. Recognizing these differences is crucial for engineers when designing foundations or implementing stabilization techniques tailored to specific soil characteristics.

Related terms

Cohesion: Cohesion refers to the attraction between similar molecules, which contributes to the internal strength of soil and water.

Capillarity: Capillarity is the ability of water to move through soil due to adhesion and cohesion forces, influencing water distribution in the soil.

Soil Suction: Soil suction is the measure of the moisture content in soil, affected by adhesion and cohesion, and influences how water is held in the soil.