Pile Under Reamer/Bell Mouth Tool

This is a tool I made a couple of years ago for Bell Mouthing the base of piles I sunk through my workshop floor (29 in total). The back of the workshop slab had sunk over 80mm and was continuing to sink at a rate of 1mm per month. I had sort the advice of professionals experienced in slab lifting and clay stabilization but at a cost of $22,000 AU this was out of the question. The guarantee for this work was like a colander, full of outs for the contractor with all the onus for any issues back on me. I organized for a Geo-Tech sample and report to be undertaken with the results (as I had assumed) coming back as unstable clay down to 1.5 Meters. I needed to increase the bearing area of any piles I sunk to ensure no movement of the slab once re-leveled and under load. As a result I designed and made a hand operated Under Reamer/Bell Mouth Tool to open out the base of the piles to 500mm from a pile diameter of 170mm to achieve this higher rated bearing load for each pile. It has now been 18 months since I completed this work and I can say that the slab is now rock solid with no movement other than some initial re-settling.

https://www.youtube.com/watch?v=6Vw44c9t_98&t=173s

Part 1 of the Bell Mouth Tool build

https://www.youtube.com/watch?v=oDeoO-B-MTc&t=17s

Part 2 of the Bell Mouth Tool build

https://www.youtube.com/watch?v=G5Hn8isBwUA

Showing the Bell Mouth Tool in action

https://www.youtube.com/watch?v=p4a_rJ3QA5Q&t=1474s

The initial kick off video to the Slab Lift Series.

Hi Me2 , love your Utube channel , what suburb/state are you in Australia ? you certainly took on a big undertakings of works to rectify the concrete slab sink. Keep up the good work

Cheers from Melbourne Australia

G'Day Peter, just down the road in Geelong.
Cam

how are you going to actually lift the slab, or is this simply an effort at stabilization?
Great video!
Thanks
Doug

did you do a video on how you leveled the slab?

G'Day Nitrous, yep if you have a look at the video's you will see how I lifted the slab and re-leveled it using the home made strong backs. It is now within +-6mm all over using the water level. I did a similar thing to my house when the slab broke its back and put a huge gap in the brickwork 12 years ago. Even today you cannot pick where it was, the perfect repair.
Cam