Failure Reason 1: Hollow Blocks and Water Trapping

What happens here

The first common reason for retaining wall failure is the choice of blocks. Many landscapers opt for the cheapest, which are often hollow and have a small lip on the back. These hollow blocks can trap water inside their cavities, especially if they are solid on top but hollow on the bottom. When this trapped water goes through freeze-thaw cycles, it expands and contracts, pushing the blocks over. An example of a hollow block with a hornet's nest inside is shown to illustrate the open cavities.

Goal: Identify hollow blocks as a cause of failure due to water trapping and freeze-thaw cycles.