Difference Between Active Earth Pressure and Passive Earth Pressure

Difference Between Active Earth Pressure and Passive Earth Pressure

Difference Between Active Earth Pressure and Passive Earth Pressure

Difference Between Active Earth Pressure and Passive Earth Pressure

Earth pressure refers to the lateral force that soil applies on a retaining or shoring system. It is affected by factors such as the structure of the soil and its interaction with the retaining system.

There are three types of earth pressure:

At-rest pressure:

This occurs when the retaining wall is stationary and the backfill soil has no tendency to move. Under these conditions, the lateral stress is zero.

Active pressure:

This type of pressure is generated when the retaining wall moves away from the backfill. Active earth pressure is lower than the pressure at rest because the soil's internal resistance is mobilized when the wall moves away from the backfill.

Passive pressure:

Passive earth pressure occurs when the retaining wall is pushed towards the backfill. The passive pressure is greater than the pressure at rest because there is a build-up of shearing resistance between the two surfaces of the soil mass.

Conclusion

Active and passive earth pressures are two stages of stress in soils that are particularly relevant for designing or analyzing shoring systems. 

Active pressure occurs when the earth exerts a force on a retaining system and the members tend to move toward the excavation.

Passive pressure is when the retaining system exerts a force on the soil. 

Because soils have a greater passive resistance, the earth pressures are not the same for active and passive conditions.