Step 1: Wall Selection Criteria for Embedment Depth
- Select the correct design table by identifying the backfill/subgrade type.
- Decide on the height of the wall.
- Check the table you have selected to find out the range of post spacings. Choose the most suitable post spacing.
- You now have the soil type, wall height, post spacing and embedment depth for your sleeper posts.
Step 2: Soil Parameters
The formulation of the cantilever log retaining wall design sheets has been undertaken based on the following soil parameters:
Step 3: Backfill Slope
The information on the tables has been based on a horizontal backfill slope only. For backfill slopes beyond this amount, engineering advice should be obtained.
Step 4: Horizontals (Waling)
See above table for waling information.
Step 5: Installation Notes
Wherever possible, place uncut ends into the ground. Where this is not practical (eg. trimmed posts or wales), coat the ends well with CN emulsion or CN oil or equivalent.
Relevant Standards for This Type of Wall
- AS1170.0-1989 Minimum design loads on structures, part 1: Dead and Live loads and load combinations.
- AS1720.1-1997 Timber structures, Part 1: Design Methods
- AS1604 – Timber – preservative treated – sawn and round. These tables were compiled by Cardno MBK (NSW) Pty Limited consulting civil/structural engineers. The information provided for guidance purposes only in the design of retaining walls. If in doubt about the interpretation of the tables or the nature of the soil combinations at the site, please seek expert advice.