212 landslip stories

I don't have much experience of this but what I have seen done here at work (one side of the land here is a steep slope leading down to a lake), is the use of retaining walls, and generous drainage channels, along with judicious planting of creepers and trees such as canary creeper that produce a strong root system that helps bind the soil.

Soil creep is quite natural on slopes, but usually is a reasonably slow process. You do not need to go to the trouble of building full retaining walls, in some areas here they have simply used rocks and boulders and positioned them at an angle to the slope and it achieves the same effect, though some filling in of soil is required after prolonged periods of rain.

I don't know if this helps you at all, the only other thing I can suggest if finding a half decent landscape artist in your area and having a chat with them - they are usually well up on the tricks of the trade and might part with some of that knowledge for free.

Category
Building/Renovation

Submitted by Anonymous (not verified) on Wed, 04/13/2005 - 06:30

Last spring was a horrendously wet one and caused many landslips in the fields around us; the effects are still being felt now, a year later, as the soil becomes super-saturated, even with relatively little rain.

It is very important to know how deep the nearest stable rock underneath your house is, so I think you need to read the Geologist's report very carefully and also to enquire if any other houses in the vicinity have experienced problems. If the movement of the land is superficial (less than a metre) then maybe you have nothing to worry about. On the other hand, if it is more profound, your architect may need to re-think the project.

Some areas of Italy can suffer from unstable soil conditions. One geometra we know will not build a house now unless its foundations rest on 5-metre deep piles. Installing these at the start of a project costs an extra €15,000 but is, he says, infinitely better than trying to rectify problems later.

On a brighter note; a house up the road from us had a similar mini-landslide on the bank about 3 metres in front of the foundations and a local geologo solved the problem by cutting grooves down the bank and inserting 'matresses'; iron cages about 2m x 1m x 1m filled with polystyrene beads. About 60 were installed, in five vertical grooves cut down the hillside, at a cost of around €5,000. The result was very effective. They channel the water out very well into a stream at the bottom of the garden and you can see they're working because the water positively gushes out when it rains. There was no further movement even in the 40 days and 40 nights of rain we had in spring 2004.

Submitted by Anonymous (not verified) on Fri, 04/15/2005 - 16:43

We try to avoid using retaining walls where possible for many reasons. They create an artificial barrier to the soil conditions and water, difficult and expensive to construct and generally need to be covered with masonry or some sort for an aesthetically pleasing finish as reinforced concrete is simply ugly.
Where possible, we adopt reinforced earthworks, which basically means using the existing soil and creating 50cm layers of soil "sandwiched" inside a geosynthetic membrane. The results are cheaper, quicker and generally you let grass grow on the 70° inclined face. Have a look at [url]http://www.tenax.net/geosintetici/rinforzo/stabilizzazione_pendio.htm[/url] to see some examples. This tecnique is pretty well known in the northern part of Italy and is really starting to gain momentum throughout the rest of the country.

David
[url]www.ourtoscana.com[/url]

Submitted by Anonymous (not verified) on Sun, 04/17/2005 - 07:03

Has anyone tried using the barriers you see along all the roads in Le Marche - I don't know their technical name but they are basically stones in wire cages. it seems to me that they wouldn't be a barrier to water and it should be possible to plant on top of them (saw it done in an English garden)

Anyway I find them quite aesthetically pleasing although I'm sure they are not to everyone's taste.

Submitted by Anonymous (not verified) on Mon, 04/18/2005 - 02:04

Just wanted to share an amusing sight with everyone. A friend living on the next road up to us was greeted the morning after the rains with a huge oak tree sitting totally upright, complete with roots, in the middle of her white road. It had seemingly jumped a stannah stairlift and slid down the steep hill before arriving in the middle of the road.

Its now been moved , sadly not replanted - but I'd love to have seen her face when she drove round the corner!

Submitted by Anonymous (not verified) on Mon, 04/18/2005 - 03:50

[QUOTE=annec]Has anyone tried using the barriers you see along all the roads in Le Marche - I don't know their technical name but they are basically stones in wire cages. it seems to me that they wouldn't be a barrier to water and it should be possible to plant on top of them (saw it done in an English garden)

Anyway I find them quite aesthetically pleasing although I'm sure they are not to everyone's taste.[/QUOTE]

These are called Gabions - I haven't used them personally - but as a Civil Engineer [some time ago] they were often used as retaining walls because they are able to deform without failing [they cope with the movement that would crack/topple a solid wall].

They are pretty labour intensive - you make the cage on site and fill it yourself - but with the use of local stone, they can be pretty cost effective. You can build in 'soil pockets' for planting into the exposed face of the gabion wall - not too many or you will weaken it.