When is a lightweight mechanical or vibratory compactor required during compaction of select granular backfill for a mechanically stabilized earth (MSE) wall?

The requirement for a lightweight mechanical or vibratory compactor to be used when compacting select granular backfill for a mechanically stabilized earth (MSE) wall is specifically mandated for areas near the wall. This is because the region immediately adjacent to the wall experiences the most significant structural loads and influences the performance and stability of the wall itself.

Using a lightweight mechanical or vibratory compactor within 36 inches from the face of the wall ensures that the backfill is adequately compacted to provide sufficient support and prevent any potential settlement or deformation of the wall over time. The effective compaction in this critical zone enhances the interaction between the wall and the backfill, contributing to the overall stability and performance of the MSE system.

Compaction methods applied further from the wall, or in other specified areas, may not require the same level of specialized equipment due to differing load requirements and conditions. Consequently, the focus on the region near the wall is essential for maintaining the structural integrity and safety of the MSE wall system.