Concrete Troubles
As a former miner your posting
interested me so I thought
I should reply.
What tunnel project is it you are
working on?
You are not going to get away
from the wear problem unless
you run a full column of water
when you are pumping your
concrete.
Why is it you are not pumping
concrete/shotcrete with a
batch plant and pump from
inside the tunnel as this is
the normal way to do your
shotcrete work as this is the
normal sequence in tunnel
construction repair.
Are you pumping the complete
mix down the tube or just part
of it and adding the rest of the
material at the shotcrete nozzle
along with the compressed air?
You need to tell me more if you
want advice since you have left
out a lot of information such as
the mix, aggregate size, sand
concentration, sand size,
plasticisers, whether you are
using an antifreeze and what
type of binder is used such
as fiberglass and its strand size
etc.
You also must realise that your mix
is changed when it reaches the
bottom of that pipeline. This is why
shotcreteing mix is done in the tunnel
at the point of installation.
You have left some things out
so I can not help you until you
tell me more. ■
Re: Conveying Concrete By Pipeline
Thanks for your reply.
I need to explain it little more.
The project is for underground cavern. The access shaft is 6.0 dia and 200m deep used for mucking of blast material / human access etc... After blasting , the surface need be shotcreted. We have already lowered shotcrete machine inside the cavern and now the materail need be taken down for doing the shotcrete.
We have two options. 1) To carry either the wet mix (shotcrete) through 8" vertical pipe line , re-mix the same at bottom , add accelerator and blast it to the surface. 2) Convey all the dry aggregates + cement through the pipe line and mix all the ingredient at bottom and feed to the shotcrete machine.
We already tried No1 option. This was successful till doing upto 350 cum . However, after that there was problem of air choking, concrete choke etc.. So the entire pipe line got waste.
We just want to know what is the method of transporting / conveying material such as aggregate / sand through vertical pipe lines to a depth of 200meters. ■
Caverns,Tunnels, Caves
Greetings and salutations lunas,
Sorry that I did catch your reply earlier,
Can you/do you have the head room use super bags-one ton super sacks of ingredients and a small hoist to lift the bags over the hopper to facilitate dumping and mixing?
If the above is not possible the use of a large 6-8 inch gravity drop pipe made of certainteed yellow mine pipe is the way to go as it is light, smooth, and easy to splice together with its plastic spline kit and easy to reuse. the only thing you will need is to buy stand offs to anchor the pipe to the wall so it will stay in place as it is ment to be held in place. and not self supporting.
It will probably cost less than victaulic grooved pipe and fittings which would be my second choice.
lzaharis ■
Conveying concrete by pipeline
I am trying to convey concrete (shotcrete) through an 8"-10"steel pipe from ground level to 200 meter down which inside a 6m dia access shaft of tunnel.
As pumping of concrete is not possible with gravity downward, we are free flowing the concrete. In the process the pipe is getting eroded due to high velocity of material inside and getting choked at some time.
I am looking for a solution, How to convey concrete through a pipe line preferably. can Sluice valve be effective in this case.
Dear Experts, Please help... ■