Stabilizing loose sand and void under slab-on-grade
Stabilizing loose sand and void under slab-on-grade
(OP)
Is there a reliable injection technique to increase the strength of a localized area of loose wet sand under anexisting 50 year old slab-on-grade? Please see the attached drawing. The area is about 9 feet by 25 feet and investigation indicates it is a very loose wet sand type soil and there is void space immediately below the slab, varying from about 1/2" to 4"±. The general surrounding area is a stiff clay, as determined from bore holes.
Is there a material that can be injected into the sand to stiffen it up, and if so, what is the material? It likely will end up finding its way into the weeping tile, so the weeping tile in the area will likely need to be replaced.
The alternative is to temporarily laterally brace the basement wall, remove the slab-on-grade in the affected area, remove the loose wet sand material and place a controlled density cementitious fill and a new slab-on-grade. This seems expensive and I want to know if there is a more cost effective solution.






RE: Stabilizing loose sand and void under slab-on-grade
Here's a link to one such product...there are several......Stabilization
RE: Stabilizing loose sand and void under slab-on-grade
RE: Stabilizing loose sand and void under slab-on-grade
I am not in the stabilizing business, but I understand one of the earliest materials is called water-glass, apparently used for preserving eggs. My old boss, B.K. Hough worked on a process called chrome-lignin, a waste liquid product from paper mils that had some stabilizing properties. Even "mud-jacking" contractors might fill the bill here.
Hey Ron, there is a famous football game on TV.
RE: Stabilizing loose sand and void under slab-on-grade
Ron - do you know if there are any contractors in the Toronto area specializing in the process? Come 9 a.m. I will call the number on the link that you sent me and see if they market in the Toronto area.
What did you do about the issue of potential clogging up the weeping tile with the injection material?
Have you any feel for what this costs? Our geotechnical engineer says that it is very expensive process and it is cheaper the excavate and replace the material below the slab-on-grade, but I find that hard to believe.
RE: Stabilizing loose sand and void under slab-on-grade
RE: Stabilizing loose sand and void under slab-on-grade
RE: Stabilizing loose sand and void under slab-on-grade
I am still interested in hearing from anyone as to whether the injected material can find its way into the weepers and how that issue has been dealt with.
On another matter, does anyone know why this forum no longer sends notice to me gmail when someone replies to my post? When I initiate my post, I check the box that says notify me when someone replies, but still it does not do so. It used to do this.
Andy
RE: Stabilizing loose sand and void under slab-on-grade
I don't believe it is that rare. Uretek was a national (possibly international) company. So it may not be the same contractor, but it could be under the same title. Essentially it is poly-urethane injection.
I haven't heard of any issues with the foam causing problems with weeping tile, although you could try talking to them and seeing what they say.
RE: Stabilizing loose sand and void under slab-on-grade
RE: Stabilizing loose sand and void under slab-on-grade