Diaphram wall in backfilled sand 1

[paganel]

I am involved in a project. Some designer want to install a diaphram wall in the backfilled and compacted sand of 30 meters. I think it is not feasible for trench stability problem.
Do any one of you have similar experiences? Or maybe some suggestion on that. I will be appreciate your comments on that.

 

[cvg]

you have to place the sand diaphragm at the same time you place the embankment on either side. Or, place the embankment with 4:1 or flatter slopes on each side and then bring in the sand in thin lifts.

 

[hokie66]

Many diaphragm walls have been constructed in sand. You should consult with a specialty piling contractor as to the feasibility at your site, and with your subsurface conditions. Bentonite slurry retains the sides of the excavation. In sand, more concrete is usually required due to loss of sand into the bentonite. If the slurry wall is the basement wall of a building, the extra concrete may result in extra labour to trim the excess concrete on the inside.

 

[paganel]

To cvg & hokie 66 thank you for you answers.Now I know it is feasible but I am still not sure for this project.30m in hydraulic filled and compacted sand. There should be some special requirement for the bentonite slurry.
I will give some addtional info here.It is a foundaiton pit in an artificial island. We still have some discussion on that. The foundation is located under -12 m and the island is 5 m. With a common ratio of the cantilever and embeddment Level, the diaphragm wall is design to be about of 34 m depth in a stiff silty clay.

 

[PSlem]

If the groundwater is brackish, it will have a negative effect on the bentonite. I would talk to a slurry wall company like Soletanche.

 

[ishvaaag]

Is in some way the subpressure issue addressed? Check it for the subfoundation soil and head. Or are the works to be made inundated?