ideas for concreting sloping bank into pond

[bodga]

Some years  ago (5) I poured some concrete over the sloping sides of my pond, we recently have had a  lot  of rain and  the whole  lot slid  into the pond, pond  is 4-5  metres  deep below  the water line, the bank is  quite steep and Im  looking for  ideas to re-do the concrete to stop it  sliding in again. Piles  will be tricky and its  only  got to  support the weight of the concrete slab not a whole  house, did think of  just smashing into the ground a load of galvanised steel  poles about a metre  down in the hope of  stopping it  sliding in again. Access is difficult. I did this  before  by just laying a  metal frame over the soil but didnt  put any metal in, guess  that was an oversight as maybe smashing in metal then would  have prevented this sliding into the water. I think piles is over the top as one guy quoted us 269k to do this which seems way over the top. Each length is  about 2.4  metres long but then the slope keeps  going down  another 4  metres to the bottom so  Ill need to stop it sliding in again. Thoughts?? Soil is  quite  hard its  not backfill or  rice  paddy theres a lot of stone in it. Total length is  about 40 metres

Edited October 23, 2020 by bodga

[ourmanflint]

The sides will need supporting at the bottom of the pond, is the base just mud?

 

[bodga]

1 hour ago, ourmanflint said:

The sides will need supporting at the bottom of the pond, is the base just mud?

 

its in various soil types  going down thru 5  metres, Im going to get  piles stuck in to stop the new concrete sliding in, there  will be a lot of sediment at the bottom.

[Migrosmarket]

I would do 2 things:

 

1. Hammer in rebar 90 degrees to the slope. Bend the rebar at the top to give a lateral bar above the soil level that will be encased in concrete. Make this bent part 30cm to give good strength. Do as many as you can as deep as you can.

 

2. Divide the sloping concrete into sections (I think you did this already but can't  see clearly) so there is not one huge weight trying to slide downwards. Within the sections add more rebar tied to the bars that are hammered in. Thinner bars will do.

 

Will you drain the pond a little to allow work below the current level? 

 

Any chance you can tie the sides into the fencing we see in the photos?

 

Could also consider taking the concrete over the top edge in each section with rebar hammered in vertically along the top edge.

[KKr]

I'd consider digging out the old concrete, if possible at all,
so in future this does not cause problems.
then
sloping the walls properly, something like one/two meters horizontal , one meter 45 degrees, someone with an engineering back ground can recommend better course of action. (See also the Thai construction guidelines for digging out Sand and gravel Pits)
strengthen the walls with geotextiles and large stones.
thought behind that is to create a though but permeable wall,
not one block of many tons of weight that inevitably will give way to the water flow.

budget question I cannot comment.

my 2cents

[jak2002003]

The water is 5 meters deep?!

[rickudon]

Possible problem is water buildup behind the concrete - cannot see any drainage holes on the front face. You had a landslip .... At that steep angle, you cannot expect concrete slabs to stay put without some anchorage, unless you start from the bottom of the pond. Also quite possibly erosion has undermined the concrete slabs from below.

 

Terracing the side will also reduce slippage risk - but hard to do on an existing pond.

[CM4Me]

The previous (good) Deleted introduced a grass with a massive and deep root system for use in situations outlined by the OP. 

 

Thais sometimes refer to as the 'Kings Grass' or more correctly as 'Paw to-wong' - just a thought

[Iron Tongue]

How about building up a wall of pre-poured concrete slabs/blocks?

You've probably seen them, they look like Legos.

 

 

[Chungju]

I did something similar to our pick nick pond. It was an existing pond with quite solid soil around it (stayed in shape several years after digging) and with soft mud bottom with ground water filling it automatically a meter or two and rest by rain.

 

Our concept for the concreate lining was this:

- Use ready made concreate slabs (c-pac) that are usually used building floors for houses (see photo)

 

- After draining the pool, we drove in concreate piles (ready made concreate fence posts) in the bottom by hand and set c-pacs laying horizontaly in top of them (see photo)

 

- The c-pacs creating the lining where then standing on these  horizontal ones and once all of them where in place we pored concreate on the bottom to make in solid one piece thing (see photo)

 

- On the top end of the c-pacs we lay some rebaring and poured concreate to finish the top (see photo)

 

 

- End result:

 

We got the c-pacs at discount as we took all slightly broken ones and any length pieces the supplier had laying around. Still for the c-pac, concreate, rebaring & etc we spent at least 100kthb. In top of this the excavator, help labour costs, gravel & etc, it was quite expensive exercise. We did most of the work ourselves and I have to say that working in the humid, soft bottom mudhole in the burning sunshine moving the 100kg c-pacs around was something I will not do again, so not surprised people ask good pay for it. 

 

Another alternative I was looking was SCG's concreate fabric, but though it is not correct for my application:

 

 

 

 

 

 

 

 

 

Edited October 25, 2020 by Chungju
remove extra photo

[bodga]

plan 180k  start in 2  weeks

[Yellowtail]

Good luck with it.

[Migrosmarket]

11 hours ago, bodga said:

plan 180k  start in 2  weeks

Hope we get a video link or plenty of stills. Interesting project. 

[Migrosmarket]

On 10/25/2020 at 1:23 PM, Chungju said:

I did something similar to our pick nick pond

Great photos.

[AsterixThai]

Sheet pile

[hotchilli]

On 10/23/2020 at 2:57 PM, bodga said:

Thoughts?? Soil is  quite  hard its  not backfill or  rice  paddy theres a lot of stone in it. Total length is  about 40 metres

Use rebars driven in.... 

[Jenkins9039]

And there's me fussing over building something like this lol

[Migrosmarket]

On 11/6/2020 at 9:14 AM, AsterixThai said:

Sheet pile

Well let's not judge the quality until its finished ......

[bodga]

Turned into a disaster as the company doing it were  supposed to be quoting for the whole  lot ie beam piles and concrete finish, now they say its  just the piles and beam which have been put in badly not deep  enough should be 2metres and some are  just 50cm and theyve walked off the job.............ongoing in another thread, theyve had 75k and Im not paying out anymore for the paltry work theyve  done.

[thaicookingchef]

I really wish you good luck to find someone with enough brain to do a correct job here...

maybe even cheaper to imports your engineers from abroad...

 

[bodga]

5 minutes ago, thaicookingchef said:

I really wish you good luck to find someone with enough brain to do a correct job here...

maybe even cheaper to imports your engineers from abroad...

 

The  long  story behind  this is at 57 Ive had enough of digging  mixing block laying stone shovelling for the last 7-8  years and when the concrete slid  into the  pond I didnt want to do it  again, Im tired so I wanted a  team to come in and just get it  done. Ive always done  all the work myself here because I know exactly what they are  like and Id  had  enough of the graft. After seeing how most of them work I had a bad  feeling right from the start, seen it  all before.

[ourmanflint]

3 hours ago, bodga said:

Turned into a disaster as the company doing it were  supposed to be quoting for the whole  lot ie beam piles and concrete finish, now they say its  just the piles and beam which have been put in badly not deep  enough should be 2metres and some are  just 50cm and theyve walked off the job.............ongoing in another thread, theyve had 75k and Im not paying out anymore for the paltry work theyve  done.

Sorry to hear that. 

[sometimewoodworker]

5 hours ago, bodga said:

Turned into a disaster as the company doing it were  supposed to be quoting for the whole  lot ie beam piles and concrete finish, now they say its  just the piles and beam which have been put in badly not deep  enough should be 2metres and some are  just 50cm and theyve walked off the job.............ongoing in another thread, theyve had 75k and Im not paying out anymore for the paltry work theyve  done.

Sorry to say that that is a normal kind of excuse for a building team that wants to quit.
 

It is one of the main reasons why everyone is advised to make sure that they pay in arrears for work done always owing money. So that when a team quits, for what ever reason they invent, they loose money and don’t get paid for the last work done.
 

That way you have money left to pay the new group.

 

builders  understand (they don’t like it and will complain and try to get paid) that if they quit early they will not get any more money. The only way to get the full amount is to complete the job as written in the contract.

[bodga]

11 hours ago, sometimewoodworker said:

Sorry to say that that is a normal kind of excuse for a building team that wants to quit.
 

It is one of the main reasons why everyone is advised to make sure that they pay in arrears for work done always owing money. So that when a team quits, for what ever reason they invent, they loose money and don’t get paid for the last work done.
 

That way you have money left to pay the new group.

 

builders  understand (they don’t like it and will complain and try to get paid) that if they quit early they will not get any more money. The only way to get the full amount is to complete the job as written in the contract.

Ive  found more recently  many companies are asking for the money upfront and wont start without it, this  co. asked for 50k I said  no. Gave them less than half to start which I really begrudge doing but again I  just want this over with.

Today the men doing the work turned up asking for  money, got the Wife to point out we didnt hire them the company  did, they subcontracted to the Co, of  course the Co are  telling  the workers  its  all our  fault  and that we are liable to pay them etc.

[thcosh]

33 minutes ago, bodga said:

Ive  found more recently  many companies are asking for the money upfront and wont start without it, this  co. asked for 50k I said  no. Gave them less than half to start which I really begrudge doing but again I  just want this over with.

Today the men doing the work turned up asking for  money, got the Wife to point out we didnt hire them the company  did, they subcontracted to the Co, of  course the Co are  telling  the workers  its  all our  fault  and that we are liable to pay them etc.

 

 

To help them start without paying, best is to buy needed materials. Then they have no reason to ask money upfront because they have nothing to buy to start working.

 

[Dumbastheycome]

I would  seriously recommend you revise  your plan to incorporate drainage from  behind  any slab on the slope. The probable cause for the original slab to slide off would be due to water pressure  behind it. I have seen an in ground  concrete swimming pool that was left  empty have the walls  implode from water pressure in the ground outside during the  rain season.

[sometimewoodworker]

3 hours ago, bodga said:

Ive  found more recently  many companies are asking for the money upfront and wont start without it, this  co. asked for 50k I said  no. Gave them less than half to start which I really begrudge doing but again I  just want this over with.

Today the men doing the work turned up asking for  money, got the Wife to point out we didnt hire them the company  did, they subcontracted to the Co, of  course the Co are  telling  the workers  its  all our  fault  and that we are liable to pay them etc.

That is as I mentioned standard practice. It’s certainly possible they haven’t been paid, but as you rightly pointed out that’s not your problem and they need to take it up with the company.

One thing you can do is tell them exactly how much you have already paid and that is the money for their wages. The company will have lied to them so you can get them attacked the company.

[bodga]

5 hours ago, Dumbastheycome said:

I would  seriously recommend you revise  your plan to incorporate drainage from  behind  any slab on the slope. The probable cause for the original slab to slide off would be due to water pressure  behind it. I have seen an in ground  concrete swimming pool that was left  empty have the walls  implode from water pressure in the ground outside during the  rain season.

The  slope of the concrete  extends  about 40cm under the max  water  line , the water  will be able to drain directly into the pond but  i will be adding some weep  holes anyway, there was  no beam  before at  all so the pressure would  have  been reduced. I believe this was  more land slip, behind the slab got very wet and it  simply slid into the water as the top layer of  soil under the slab broke  down.  

[bodga]

3 hours ago, sometimewoodworker said:

That is as I mentioned standard practice. It’s certainly possible they haven’t been paid, but as you rightly pointed out that’s not your problem and they need to take it up with the company.

One thing you can do is tell them exactly how much you have already paid and that is the money for their wages. The company will have lied to them so you can get them attacked the company.

Wife already told them the Company has been paid  total 75k and sent  them the LINE payslip to show them.

Also my Wife NEVER signed their  Company contract so in effect there is  NO contract.

[CharlieH]

18 hours ago, sometimewoodworker said:

Sorry to say that that is a normal kind of excuse for a building team that wants to quit.
 

It is one of the main reasons why everyone is advised to make sure that they pay in arrears for work done always owing money. So that when a team quits, for what ever reason they invent, they loose money and don’t get paid for the last work done.
 

That way you have money left to pay the new group.

 

builders  understand (they don’t like it and will complain and try to get paid) that if they quit early they will not get any more money. The only way to get the full amount is to complete the job as written in the contract.

 

I did similar and worked out a plan of "Stage payments" do this, agreed complete, then get paid. They told me what was needed, I supplied any and all materials as required.