Advice or Ideas Wanted: Earth Walls

Hi all, I would really love some advice or ideas about the earth walls of a building I have taken charge of.

Myself and my husband recently took over the care and maintenance of a building at the school where we live which has some earth walls. The previous designers and builders left in a bit of a hurry and although the building is complete and integral now, the earth walls have been left only partially filled in, so that the tyres behind the earth are somewhat exposed.
As the building is designed with the tyres and earth mainly for show and the main structure is concrete we think it would be ok to leave the walls exposed, although it does not look very pretty.

Some basic information about the site:
- The main building is made, as mentioned, of concrete and tyres, with 5 'alcoves' of earth walls around the outside
- We are in Central Thailand, probably around 350m above sea level
- The earth used in the earth walls, and all around the building, is heavy clay

We are mainly designing a forest garden and children's playground around the building and do not wish to become overly involved with the building itself, however, here are some of our challenges:

- The director of the school is unwilling to spend more money on completing the earth walls so if we are to finish filling them in it would have to be by hand
- The ground around the building has already been levelled to much lower than before so if we are to get more earth it would have to come from further away
- That said, the director is very keen to get the walls planted up ASAP so that they look good
- Since we are in a tropical environment, we think that the earth may need to be landscaped in order to prevent erosion, but we do not know the best way to do this. There are already some signs of deep erosion channels from the few rainstorms we have experienced in the dry season, and when the rainy season begins in May we need to already have some kind of erosion control in place
- Bearing the above in mind, we were wondering if it would be appropriate to make terraces on the earth walls? Our concern here being that they might encourage infiltration of water into the soil and thus into the foundations
- Also, as the walls need to be super low-maintenance, we were wondering if anyone has ideas for tropical species with shallow roots which would be appropriate

Here are some photos of the earth walls themselves: https://www.flickr.com/photos/153762705@N07/albums/72157679175293283

We would greatly appreciate any ideas and suggestions for what to do in this situation. It is clearly not ideal but we would love to turn the problems into solutions, with your help if you wish.
Thank you!

The link isn't working for me.  Can you check it, or check that the photos are public?

Hi! Sorry, here is the working link: https://www.flickr.com/photos/153762705@N07/albums/72157679175293283
Thanks

A kind of chicken wire nailed to the floor will help to introduce perennials and maintain the dirt.

Make a sandwich of - straw/fabric texture(above the clay) - chicken wire nailed  to fix the clay and straw - Good soil and perennial seed on top and treat it like a "lawn" . Do it in the spring and maintain until rain season.

Hi Charlotte, What about using some kind of gunny sack material? I see landscaper use it along steep slopes of highways until seeds take root. Seems like a good idea. Unlike chicken wire, it will eventually just bio-degrade, but by then the ground cover plants would have taken root.

Seems like a grass of some kind (maybe Vetiver grass?) would have a good network of roots, and act like a thatch roof... overlaying the lower levels.

Good luck.

Try to reduce run-off flow velocity, maybe through diversion, without having it sink in.  Higher velocity water will carry more soil away, more quickly.  

RYE Grass or the equivalent for your climate. I dont much like grass but we used alot of Annual rye seeds on our fresh earth works to help stabilize the soil. Because its annual you could use it for a year (or A season) and its roots would be intact enough to plant something else after it has stabilized.  The annual Rye grass works pretty good in red clay, crimson clover pretty good as well but you have to rake it in more than the rye grass. Your soil looks alot like ours in south Georgia.
https://permies.com/t/57360/a/41616/IMG_20150427_181145_992.jpg
Link to some fresh planted RYE