Lack of Drainage Fabric and Drainstone

What happens here

The presenter demonstrates that soil was placed directly against the backside of the retaining wall. This is identified as a critical mistake. Ideally, a drainage fabric should be installed, extending up and around the backfill, followed by drainstone (gravel) behind the wall. The absence of this fabric and drainstone allows the soil to mix with any aggregate, creating a 'mud rock' condition, which further exacerbates drainage issues and structural instability.

Goal: Recognize the importance of drainage fabric and drainstone in preventing soil saturation and mixing.