Is this "cliff" site stable?

[cheeryble]

Hi

We are getting some unregistered land from another family member. One or another family member own nearly all the local lots of land which has many advantages and one starting to age will live on a low corner of the land which will not only give him a home it will add security and maybe a gardener/handyman (in a few years another person for me to look after!!).

Important to me is that whilst the whole area is elevated a bit one side of the actual site is like a small cliff (see photo, there's a flat area on top and it slopes down the other side.

The slope looks damned steep, 75 degrees maybe even more?

I also attach a photo of a bit of cut land a hundred yards away which MAY be similar composition……it has an element of clayishness about it and is damp, though not like true clay and a lump will hold together but will break easily. As you can see the land on the track up looks a bit sandier like din dang though that may be surface I havent done a proper exploration of the cliff face and am not at the site.

Question is how do we decide if it's safe to build and it ain't all gonna to collapse and us with it?

(I might add that whilst I can't imagine how a steep face like that occurred naturally I can't see how it can be man made…it's an undeveloped area…. so I guess it is natural).

Edited January 17, 2014 by cheeryble

[cheeryble]

ps That cliff is higher than it looks…..more is hidden by undergrowth

[Crossy]

I'm no soil or structural engineer, but I'll still throw in some ideas.

What sort of structure are you looking at building? How near to that 'cliff'?

I'm assuming you want to be on top of the hill, King of the Castle

Can you access the bottom of the cliff to see if anything has been falling off recently? Getting into stabilising land can rack up the $$$ really rapidly

[trogers]

Gauging from the height of the banana trees, the cliff is about 6-7m in height.

Even if there is no landslide, the exposed face of this cliff will be eroded over time.

The final stable slope will be at an angle of 42^o from the vertical at the bottom of the cliff. You can still build a single storey house with the first row of support footings at an angle of 45^o from that vertical.

[cheeryble]

I'm no soil or structural engineer, but I'll still throw in some ideas.

What sort of structure are you looking at building? How near to that 'cliff'?

I'm assuming you want to be on top of the hill, King of the Castle

Can you access the bottom of the cliff to see if anything has been falling off recently? Getting into stabilising land can rack up the $$$ really rapidly

Thanks Crossy

I'm thinking of a holiday type chalet for now but design so I can add alter on maybe a full house

Yes I want to be King of the Hill!!

I'm not near there now yes I must get to the bottom area but i havent seen any fresh from above (then again I hate heights and don't hang over edge)

Edited January 17, 2014 by cheeryble

[cheeryble]

Gauging from the height of the banana trees, the cliff is about 6-7m in height.

Even if there is no landslide, the exposed face of this cliff will be eroded over time.

The final stable slope will be at an angle of 42^o from the vertical at the bottom of the cliff. You can still build a single storey house with the first row of support footings at an angle of 45^o from that vertical.

thanks for the excellent (as usual) thoughts...

1.Gauging from the height of the banana trees, the cliff is about 6-7m in height.

I think it's considerably more than 6-7m some is hidden by that grass a wild guess 10-12m.

2. Even if there is no landslide, the exposed face of this cliff will be eroded over time.

Thats my concern….am now thinking I can check bottom as Crossy suggests and also take a soil sample simply see what happens when I put it in water if it holds together nicely i think no problem.

Also thinking maybe some sort of vegetative protection , don't know exactly if thats possible so steep a slope

3. The final stable slope will be at an angle of 42^o from the vertical at the bottom of the cliff. You can still build a single storey house with the first row of support footings at an angle of 45^o from that vertical.

Ah now this is what i'm looking for west case scenario that's interesting stuff.

Maybe i can make wife's room at 40 degrees and mine at 45

I guess the soil consistency and drainage really is the important factor.

As I remember the the flat top is actually a slight slope AWAY from the edge, gradually increasing to a 10-15 degree slope after the flat bit.

ps How did you make the degree sign?

Again thanks!

Edited January 17, 2014 by cheeryble

[Crossy]

The degree symbol is a small o with superscript tags (6th option from the left on the edit bar X²)

In edit mode select your 'o' and click X²

[cheeryble]

The degree symbol is a small o with superscript tags (6th option from the left on the edit bar X²)

In edit mode select your 'o' and click X²

Bless you my son

Testing 45^{o hehe}

[keeniau96]

I have a similar situation at my property in Phuket. The back is almost vertical with some narrow, deep gullies cut into it. But the face itself is very stable, have been living here for six years now. Overall this is a hillside with a former tin mine cut into it. The steep face is actually the eroded granite (I have some beautiful fresh granite uncovered during my foundation work), and the thick overburden is actually a welded laterite wherein the ferruginous material has oxidized and forms a durable thick crust.

That is my situation in Phuket, yours appears to be different eg. the friable sands.

I found several photos that show exactly my situation with the steep sides but the Image option requires a URL and the photos are on my computer (desktop, HDD, also in my Dropbox).

[Daffy D]

I have a similar situation at my property in Phuket. The back is almost vertical with some narrow, deep gullies cut into it. But the face itself is very stable, have been living here for six years now. Overall this is a hillside with a former tin mine cut into it. The steep face is actually the eroded granite (I have some beautiful fresh granite uncovered during my foundation work), and the thick overburden is actually a welded laterite wherein the ferruginous material has oxidized and forms a durable thick crust.

That is my situation in Phuket, yours appears to be different eg. the friable sands.

I found several photos that show exactly my situation with the steep sides but the Image option requires a URL and the photos are on my computer (desktop, HDD, also in my Dropbox).

Below the more reply options window is the option to attach files/photos from your computer.

Try not to post large photos - I usually reduce mine to 800x600

[cheeryble]

Thankyou Keeniau

and yes Daffy put you right there.

I was going to make some checks before purchase but she-who-must-be-obeyed tells me she has told her sister she'll take it so it's a done deal.

I think I have two concerns……the cliff and the official status of the land.

Sister and family own all the lots nearby and I think I'll let them worry about the status…..it's certainly not military and I can't see how forestry owns anything there. I know it's previously been measured up by officialdom so hope it's on track for eventual chanot.

As for the cliff my guess is although it's certainly more friable than your area, hey how long does it take to erode? 2 years? 500 years? Then we don't lose the land we just have a bit less on top. I think the drainage all goes the right way away from the cliff (probably why it is OK). I learn that coastal erosion is almost all down to sea action undercutting the cliffs and that is not happening of course.

So I shall take a visit and look for any cracking (which I didn't see before), suss out the drainage (and whether it can be improved) and test out the cliff side for friability and look for any falls (which I also didn't see) and check the vegetation cover or not or if it's possible.

Depending on all that will suggest how much care to take of one day siting a building…..it can always go on the gentler slope side anyway….great view….and maybe have a garden and sala on top.

The very worst case is get a bulldozer and digger and alter things around a bit but I doubt it's necessary.

This is really my gift to my wife for her future so as she ages if she chooses she can live near her wonderful extended family and the kids as they grow up. If it aint perfect so what….it always will produce crops.

If I can enjoy it too so much the better.

Edited January 18, 2014 by cheeryble

[manarak]

if you would like to preserve the "cliff", you might look into planting trees or bushes of a sort that develops a lot off roots

[cheeryble]

if you would like to preserve the "cliff", you might look into planting trees or bushes of a sort that develops a lot off roots

Indeed, and I believe vetivert.....whose aroma I love.....is used in some countries on slopes.

Trouble is it's so steep I don't know how it could work.

I am however a big fan of vertical gardens. It would be a question of the work and expense involved and limiting the corrosive effects of the irrigation to the face. All that and actually it ain't visible from the area on top probably knocks that one on the head too.

Some creeper planted and watered at the bottom which also roots adventitiouly in the face is a maybe just let it grow.

Is there such a thing?

Sent from my iPad using ThaiVisa app

[krisb]

Get an engineers advice.

[cheeryble]

The thought occurs that this cliff is not natural.

Duh!

I think emore likely is it was dug away some years ago for use as fill for house sites on the main road nearby where there was low land for rice, it needs a meter or two added. This would be a nearby easy spot to dig from, and they've simply cut into the end of the hillock.....no quarrying, easy peasy lemon squeezy.

It occurred to me that the guys who dig quarries would know the safe angle to dig at, their very lives depend on it and they often do it right next to chanot boundaries whcih could have big legal implications.

South of Nong Khwai south of CM where there are lots of quarries all dug at a pretty steep angle and all seemingly stable.

Looking forward to another visit so we can inspect the cliff face and get some clues. In fact Uncle Serm may just be able to tell us all this.

We now learn he has lived there 7 years......eager to learn if he was the first resident there, as seven years isn't very "historical" use of the land. Anyone know how all that works as a friend says the tabien bahn is what we need?

Sent from my iPad using ThaiVisa app

Edited January 20, 2014 by cheeryble