Anchored wall in collapsible soil

[pileexpert]

Hi everyone,

We are going to stabilize an excavation using anchored wall, at depth 10m we faced collapsible soil which I think it should be loose GP withoud any cohesion, our hole length is 17m and when we drill with 10 degree slope at length 6-7 m hole collapses and it is imposible to go further and install strands into the hole, is there anybody to to help me what the best solution is and has anybody encountered the same situation and what was the solution? by the way we intend to apply a 60 ton load at the strands so it is important to use strands not monobar or sth els.

Regards

 

[crcivil]

You might want to consider employing 51 mm self drilling hollow bars , drilling and grouting simultaneously.

 

[crcivil]

These bars can be pre-stressed to 60 t.

 

[oldestguy]

Usually in unstable ground a casing is advanced along with the drilling. Some use of injecting an agent with cementing capabilities is done in tunneling through clean sands, then followed by the excavation, without casing. There are firms in the US that do this. One of the old time cementing agents for this is "water glass". Even lignin from paper making works some in this regard. I'd look to the injecting method first, then do your job.