impending doom...60 ft x 6ft stone wall ready to collapse

I cant post pics from work but will do so when I'm home. In front of the house I have 2 60 ft long x 6 ft high stone walls with steps in the middle separating them. These walls 'hold up' my front yard and my house is up on the hill. My driveway is on the left side of the property and the left side wall has bowed at the center for over 15 years and the one corner near the steps has even separated but last night in the 3 inches of rain, one large stone in the center popped out so i'm very worried now. I'm going to try to dig a bit of dirt out and replace it after work.

the right wall fell in the late 90s and was replaced at a cost of 5k, the left side was estimated in 2004 to cost 15K. So i never had it done and the old mason retired and isnt even available. the issue was clogged drainage and all that water pressure over the years.

fixing the wall itself sounds impossible (even if someone was brave enough to want to dig behind it then 'push it back lol') and i realize that. but i wanted to try to put off collapse longer by perhaps putting in a temporary drainage system. I was thinking of something about 10 ft back from the wall (dont want to dig anywhere near it) in the way of a 2 ft trench with pvc pipe and totally filled with stone and just a top layer of soil. then i'd pop out a stone so the pipe drains to my driveway. Not a great solution but i want to postpone collapse at almost any cost. I have about 50ft of sloping water that pounds the wall from the front yard every storm

or if the wall does fall, i was thinking about paying someone with the right equipment to haul all the stone up my driveway and into my back yard...i know that wouldnt be pretty and it's probably unrealistic but i hate to toss all that great stone and someday when i'm rich id like to rebuild. also it will look horrible to not have some kind of wall up but you cant do anything but stone or it would look stupid. and if it does fall i dont even know what ill do to 'fix' the hill. i need suggestions on that as well

will post pics tonight so you can understand this better and appreciate any input..thanks!

 

If you are going to dig, you might as well fix it & be done with it. Suppose you built a temporary support in from of it, using 4x4 fence posts & 2x4 horizontal rails? Then you can dig as close as you want, for your drainage. You may even be able to use come-a-longs to reposition & secure it.

 

It is unlikely that there is a quick fix. You are correct, saturated soil exacerbates the problem. Good drainage will slow down the failure, but it will not stop it. The wall will need to be rebuilt. I would probably choose to rebuild the wall using a geotechnical fabric to stitch the wall to the soil. These systems typically use CMU with proprietary connection devices to fasten the fabric to the wall. If you can devise a robust connection of the fabric to the stone the fabric should hold back the wall.

Don't park vehicles near the wall. If you have stones popping out I'd play it safe. Walls do fail catastrophically.