Understand the Impact of Heavy Rainfall and Erosion

What happens here

The expert further elaborates on how heavy rainfall exacerbated the issue of building on disturbed soil. He explains that when heavy rainfall occurs, such as the '4 inches in one day' mentioned earlier, erosion takes place. This erosion pulls out the 'stuff' (referring to the soil and possibly backfill) from the base of the wall, leading to its collapse. This highlights the combined effect of an unstable foundation and environmental forces, which can quickly lead to catastrophic failure. He emphasizes that even under construction, a properly built retaining wall should not fail in this manner.

Goal: Recognize water as a significant factor in retaining wall failure and the importance of proper drainage.