Lateral earth pressure

Definition

Lateral earth pressure is the pressure exerted by soil on a vertical surface, such as a retaining wall, due to the weight of the soil and any additional loads acting upon it. This pressure is crucial in determining the stability and design of structures that retain soil, as it can lead to potential failure if not adequately accounted for.

5 Must Know Facts For Your Next Test

1. Lateral earth pressure is typically analyzed using Rankine's or Coulomb's theories, which provide equations to calculate both active and passive pressures.
2. The direction of lateral earth pressure is horizontal, acting perpendicular to the surface of a retaining wall or other vertical structure.
3. Lateral earth pressure can vary significantly with changes in soil conditions, such as saturation levels and loading from structures or vehicles.
4. The design of retaining walls must consider not just static lateral earth pressures but also dynamic pressures from factors like earthquakes or vibrations.
5. Proper drainage behind a retaining wall is critical because water can increase lateral earth pressure significantly, leading to potential structural failure.

Review Questions

• How do active and passive earth pressures differ in relation to retaining walls?
  • Active earth pressure occurs when a retaining wall moves away from the soil, causing the lateral pressure exerted by the soil to decrease. In contrast, passive earth pressure happens when the wall moves toward the soil, leading to an increase in the pressure. Understanding these differences is crucial for designing retaining walls that can safely withstand varying conditions without collapsing.
• Discuss the importance of drainage in managing lateral earth pressure behind retaining walls.
  • Drainage plays a vital role in managing lateral earth pressure as water buildup behind a retaining wall can significantly increase the soil's weight and consequently the lateral pressure exerted on the wall. Proper drainage systems help to reduce hydrostatic pressure, which prevents excessive loading on the wall and reduces the risk of structural failure. Ensuring that water does not accumulate behind a retaining wall is essential for its long-term stability.
• Evaluate how changes in soil cohesion might influence lateral earth pressure calculations in retaining wall design.
  • Changes in soil cohesion can have a substantial impact on lateral earth pressure calculations. Higher cohesion typically leads to lower lateral pressures because cohesive soils can hold together more effectively against sliding forces. Conversely, lower cohesion results in higher lateral pressures since the soil is more prone to movement under load. Thus, accurately assessing soil cohesion is essential for designing safe and effective retaining walls, as it directly influences both active and passive pressure scenarios.

Related terms

Active Earth Pressure: The condition of lateral earth pressure when a retaining wall moves away from the soil, resulting in lower pressure on the wall.

Passive Earth Pressure: The condition of lateral earth pressure when a retaining wall moves toward the soil, resulting in increased pressure on the wall.

Cohesion: The measure of how well soil particles stick together, influencing the amount of lateral earth pressure exerted on a structure.