In order to keep a trench like that open, it is filled with a bentonite slurry that has a higher density than water. That keeps hydrostatic pressure working outward on the trench walls.
When the backfill material is placed, it is dumped at the top of the trench and it slides down a ramp of unexcavated material or previously placed backfill in such a way that it does not drop through the liquid slurry and separate as it reaches the bottom.
Glancing through Google, this reference seems like a fairly decent one. If this doesn't answer all your questions, let me know.
http://www.tceq.state.tx.us/comm_exec/forms_pubs/pubs/rg/rg-282_189585.pdf
Got it, thanks.
I was interested because there is a chemical plant here that had contaminated the surrounding area and they were looking into similar technologies to prevent the contaminants from further leaching out and affecting the groundwater and the surrounding neighborhood. They were looking at a curtain some 200 feet deep, surrounding the plant, which is roughly a mile square in area.
To All, bentonite can be considered, for non-engineering purposes, to be "clay", which may help in understanding the technology under discussion.
Got it, thanks.
I was interested because there is a chemical plant here that had contaminated the surrounding area and they were looking into similar technologies to prevent the contaminants from further leaching out and affecting the groundwater and the surrounding neighborhood. They were looking at a curtain some 200 feet deep, surrounding the plant, which is roughly a mile square in area.
To All, bentonite can be considered, for non-engineering purposes, to be "clay", which may help in understanding the technology under discussion.