Agricultural fence sinking into the ditch, self build retaining wall.

Ectophile

I would be inclined to dig a trench on your side of the fence.  Deep enough to get down to the pipe and as wide as the ditch.  Then make a reasonably sturdy dam/retaining wall in that trench.

Sand/cement filled sandbags, as recommended above would work.  Or railway sleepers if you have someone strong enough to move them.  Or your original suggestion of metal channels hammered into the ground and sturdy boards.

Then back-fill the trench around your new wall, tamping everything down firmly as you fill.  Don't just shovel in loose soil and stamp on it a bit at the end.

20up

Hi again, so I have managed to clear around the crushed plastic pipe, shined a torch and see what I believe is leading to  an old clay pipe. This pipe is seen at the other end of the land. Its about 8 to 10 foot from the crushed pipe to the clay pipe, so I am not going to dig all that out, however I would like to shore up the entrance by slotting in a pipe or coupling that wont get crushed by sandbags / dirt that I will eventually place on top. Are there any recommendations please ?
Something like this ?
Male-Male Duct Coupling 600mm Galvanised | Metal Ducting (i-sells.co.uk)

Eldi_Dos

Could you give a estimate of the diameter of clay pipes?

20up

Eldi_Dos said:

Could you give a estimate of the diameter of clay pipes?

Just gone to the other end where it is exposed, around 9.5 inches in diameter

Eldi_Dos

That is a good diameter will take a good flow.

The plastic pipe from fence to clay pipes  do you think it is crushed or is it a oval pipe?

What I would do is dig a bit more out in front of pipe entrance then create a semi circular coffer dam to "just" above level of pipe with sand bags filled with a sand and cement mix. Once set fill area between pipe and sandbags with a coarse gravel to level below pipe,hopefully this setup will keep debris out and allow free flow of water.

If you do feel the plastic pipe is collapsing you could brace it with two lengths of suitable diameter plastic pipes cut to length and braced apart with some threaded rod, nuts and washers then put in place so they sit flush with entry to main pipe but sit to the side.

20up

Eldi_Dos said:

That is a good diameter will take a good flow.

The plastic pipe from fence to clay pipes  do you think it is crushed or is it a oval pipe?

Thanks, i'd say its crushed. At some stage unknown when, bricks and dirt have been placed on top, almost squashing that end part like a sandwich. I removed these and will try bending back up using a car jack. (Not holding much hope though).

The galvanised couplings I am looking to force in to allow (at least) a circular entry to prevent crushing. Do you think this will work ? I can then do as you advised. (Cheers for that)

Eldi_Dos

The thing is with drainage anything metallic is eventually going to corrode so I would look into some other material.

Trying to open up the entrance, its a bit Heath Robinson, but would a deflated football placed in there and inflated slowly do the job.Then you would just need short section of similar diameter plastic pipe to keep its shape.

20up

Good advice many thanks @Eldi_Dos . With the Dam idea, just so I have construed correctly, build it up so there is a lip just above the bottom section of the pipe so that acts for catchment of sticks and crud

Twinwall Coupler - JDP (jdpipes.co.uk)  , would this twin wall coupler work ?

Eldi_Dos

My instinct would be to take the sandbags to just above top level of pipe and have gravel sitting about 50 mm below bottom of pipe, this would act as a trap to collect any debris, but hopefully most of that would get caught in front of sandbags.
The couplers its hard to say but I would think a coupler will have less strength than a piece of pipe.

20up

Hi so I have measured the clay pipe again at the other end and it comes out as shown in the picture. If I wanted to remove the makeshift pipe and connect a proper pipe, what fittings would I need ?
Measurement shows outside to outside measurement