Paver Block Problem
I'm not sure if I understand you question, but if you want a your 8 ft circle level, you could build a retaining wall at the "front" of the circle, backfill it with soil from the "rear" of the circle or you could remove the soil from the rear and build a retaining wall to keep the 18" from falling.
There are concrete wall blocks that are sold at a few homecenters that could work for you.
If you want the circle to follow the slope, you could mark the circle out on the slope,find some flexible edging material and fit the edging material into the soil, following the mark on the hillside. Dig out the material inside the circle to the depth for your gravel and sand from the surface of the hillside and then work upwards from the "front" of the circle to the "back". The edging could maintain the curve and by working from the front to the back, the pavers at the "back" of your circle would be supported by those in the front.
- 15 Old House Features We Shouldn't Abandon
- 17 Tiny Bathrooms We Love
- 30 Things Everyone Should Know
- 16 Sneaky Storage Ideas
- 20 Easy 60-Minute Home Improvements
- 9 Ways to Troubleshoot the Furnace
- 11 Real Haunted Houses to Visit--If You Dare!
- 9 Alternative Uses for Toothpaste
- 133 Smart Storage Ideas for the Whole House
- 16 New Ways to Store Kitchen Necessities
- 8 Ways to Make a Small Room Look Big
- 21 Expert Picks for Fail-Safe Colors
- 10 Fall Door DIYs for the Best House on the Block
- The Cheapest Ways to Boost Home Value
- 10 New Uses for Old Doors
- 10 Unexpected Uses for Spray Paint
- 8 Unique Ways to Build Your Own Table
- Woodworking for Beginners: 10 Projects
- 8 Amazing Handmade Kitchen Counters
- 10 New Uses for Old Dressers
- 7 Upgrades You Can Do in Under 300 Seconds
- 10 Thrifty DIY Ways to Organize Your Home
- 26 Easy Painted Pumpkins for Halloween
- 9 Totally Amazing Mobile Home Makeovers
- 5 "Make in a Weekend" Bookshelf Projects
- 9 Decorating Lessons We Learned from Social Media
- 10 "Zero Dollar" Storage Hacks
- 121 DIY Ideas for Halloween
- The 10 Best Things to Buy Secondhand
- 16 Must-See Coffee Tables You Can DIY—Easily!