Huge retaining wall ideas
Huge retaining wall ideas
(OP)
I need to design a reconstruct of an area damaged by erosion. The area in question is at the top of limestone bluffs overlooking a major river. Total elevation difference is 120 ft.
The only thing I can think of is to excavate the material loosened by erosion, then build a drainage path for the water and retaining wall with soil nails into the limestone for tiebacks and work up from the base.
I'll be getting some soil borings, including coring into the rock. Any ideas or suggestions would be greatly appreciated. In the words of the owner, "I'm not looking to save money on this. I want a solution to last 100 years."
M-I-Z
The only thing I can think of is to excavate the material loosened by erosion, then build a drainage path for the water and retaining wall with soil nails into the limestone for tiebacks and work up from the base.
I'll be getting some soil borings, including coring into the rock. Any ideas or suggestions would be greatly appreciated. In the words of the owner, "I'm not looking to save money on this. I want a solution to last 100 years."
M-I-Z





RE: Huge retaining wall ideas
RE: Huge retaining wall ideas
I would consider rock bolts though rather than soil nails to stabalize the rock face. As for the necessity of soil nauils, ythat would be for any loose material that might sluff off in the future or exists now. Depending on what the Geotech says, perhaps a combination of the two would be your best approach.
Maybe even adding a gunnite surface over a cyclone fence mesh secured by rock bolts could be considered here.
Mike McCann
MMC Engineering
RE: Huge retaining wall ideas
EIT
RE: Huge retaining wall ideas
1) perform slope stability analysis to determine global stability or not
2) based on results of investigation and analysis, you might do one or more of the following:
a) remove some of the overburden to reduce the stress
b) surface dewatering at the top of the cliff (divert and remove surface water going over the slope or into the ground near the top)
c) groundwater dewatering to lower the pressure on the cliff wall (wells, toe drains etc)
d) blast the slope back to an acceptable angle or buttress the bottom
e) rock bolts with shotcrete facing on the bad parts
f) rock fall netting on the loose parts
g) just monitor the slope
RE: Huge retaining wall ideas
RE: Huge retaining wall ideas
The erosion has partially loosened some of the limestone, so the area of concern extends farther down the slope.
My question is about the constructability of such a tall retaining wall. Typically, I see Geogrids extending back from MSE walls. However, with a 120 ft wall, the Geogrids would not be able to extend far enough before running into the limestone. That is why I was thinking about soil nails/micropiles for the tiebacks.
Does anybody have experience with retaining walls this tall?
RE: Huge retaining wall ideas
Reminds me of some treatments I have seen along the Mississippi, specifically DuBuque, IA. There the walls are made of local stone blocks.
I did one like this at McGregor, IA at the Fish and Windlife headqtrs.
RE: Huge retaining wall ideas
RE: Huge retaining wall ideas