To fully mobilize the passive soil pressure, the lateral strain is generally what compared to the strain for active soil pressure?

To fully mobilize passive soil pressure, the lateral strain must be greater compared to the strain required for active soil pressure to develop. This fundamental concept stems from the differences in how soil reacts to loading under active and passive conditions.

In an active state, the soil is experiencing lateral movement away from the wall or structure, which allows it to expand, resulting in lower lateral stresses. The active earth pressure is mobilized when the soil reaches its active failure condition, where it can no longer resist the lateral forces against it.

Conversely, in the case of passive pressure, the soil must be compressed against the wall or structure, which requires a greater amount of lateral strain to mobilize the increased stress necessary to overcome the soil's resistance. The passive condition represents the maximum lateral resistance that the soil can provide, which necessitates significant lateral deformation to achieve that state.

This relationship between strain and pressure mobilization is crucial in geotechnical engineering and foundation design, as it informs decisions about wall design, slope stability, and how structures interact with their surrounding soil. Understanding this distinction between the conditions for active and passive soil pressures allows for more effective designs that account for these varying soil responses.