Retaining Wall Failure

[3 Horse Ranch]

This is general information. How did you determine how far back to tie the wall? It sounds like you are using pre-engineering? How tall is "your wall? How did/do you determine "good foundation?"
Not trying to bust your chops but I have been trying to get across to posters about the dangers of not getting proper engineering.

It is not rocket science but it is science!

Any wall higher than 4 feet requires permitting and engineering here. Even at 4 feet walls can and do fail without some planning, thought and preparation. I am not an engineer, but if I were to build a tall wall without an engineered plan I would determine what angle the natural soils are stable and run my geogrid progressively back to that angle and start tying at a low level and provide lots of drainage .
Soils differ so some walls require more tieback than others.

 

[3 Horse Ranch]

Being a soil scientist is a dirty job.

Bruce

But somebody has to do it.

 

[fishdrivel]

Any wall higher than 4 feet requires permitting and engineering here. Even at 4 feet walls can and do fail without some planning, thought and preparation. I am not an engineer, but if I were to build a tall wall without an engineered plan I would determine what angle the natural soils are stable and run my geogrid progressively back to that angle and start tying at a low level and provide lots of drainage .
Soils differ so some walls require more tieback than others.

Your soil there has low clay contact. can be very granular.
Soils in NC, SC, and GA Piedmont are all clay, some of it expansive.
You can dig 100 miles wide literally in some parts of the Piedmont without hitting a single rock of any size. The rainy season is 12 months! I worked in similar soils in Okinawa and the Japanes put tieback 40 deep into the fill. They still fall down because of poor engineering. 4' gravity walls should be engineered but you have to draw the line somewhere. Codes SHOULD say that 4' gravity walls should not support structures within 5'of the wall but they don't.
My 1st 4' wall fell down. Maybe it is just me?

 

[3 Horse Ranch]

Your soil there has low clay contact. can be very granular.
Soils in NC, SC, and GA Piedmont are all clay, some of it expansive.
You can dig 100 miles wide literally in some parts of the Piedmont without hitting a single rock of any size. The rainy season is 12 months! I worked in similar soils in Okinawa and the Japanes put tieback 40 deep into the fill. They still fall down because of poor engineering. 4' gravity walls should be engineered but you have to draw the line somewhere. Codes SHOULD say that 4' gravity walls should not support structures within 5'of the wall but they don't.
My 1st 4' wall fell down. Maybe it is just me?

The 4' code is for basically decorative walls without a surcharge from a building, driveway or parking area or upper retaining wall and I think it is more like 10' away.

 

[ameliasolis]

No, not my wall! But rather a new large housing development up on a hill just finished this retaining wall a few months ago... then the biggest rainfall we've seen in years in San Diego came. Could have been worse, I guess but then again this is a pretty big failure in my eyes.

The wall I installed right around the corner handled the rain with no issues. But then again it has 30 yards of crushed rock in it.

having the same issue.

 

[dodge man]

Sometimes those stacked blocks are the wrong thing to use. A engineered reinforced concrete retaining wall is always going to be better when they start getting tall.