Structural Design of Grouted Ripraps/Concrete Slope Protection

[X-Wing]

Generally, we design structures that serves as "Soil Retaining Structures" to resist soil pressures, including earthquakes, that's why we came up with gravity walls, cantilever walls, sheet piles, etc.

Also, we use ripraps, concrete slope protections, rubble concrete sometimes with a thickness of 0.2 to 0.5, with specified slopes, to "retain" the soil, or practically for erosion control. The main factor in designing this is the hydraulic velocity.

Now, correct me if i'm wrong, so practically structures such as ripraps/grouted ripraps, are design to prevent soil erosion from effects of water current from rivers, not from the effects of soil movements?

Also, what is the purpose of using grouted ripraps for specified slopes on embankments? How are they analyzed?

How about sheet piles or other piles with pile caps connected to inclined grouted riprap or concrete slope protection? How are they designed?

Slope stability?

Thanks in advanced!

 

[cvg]

generally grouted riprap is used for erosion protection only, it is not recommended on slopes that aren't already stable

 

[X-Wing]

How do we consider (generally) or rule of thumb that the slope is stable?

I knew (from my boss) that generally a slope with 45 degrees is practically stable, but still depends.

Very Truly Yours,

- andru18

 

[oldestguy]

Be careful about grouting rip-rap, channel paving, slope protection and the like. Too often water flowing over, or outside these will get under at the edge or a crack and eventually will start to undermine it. Then, the usefulness is gone and all you have is a rigid group of rocks or slabs with no function. Paved channels also seem to suffer from this effect quite often. It takes care in preparing the support area so that it does not tend to erode easily and then undermine the paving.

 

[fattdad]

a 45 degree slope is 1H:1V. There are few natural soils that will return an appropriate safety factor at 1:1!

Rip rap can be used to increase buttress at the toe of a slope, which would return an increase in the overall "global" safety factor.

Grouted rip rap will act as a hydraulic barrier. If it's on a 1:1 slope in short order you'll get fairly high hydrostatic pressures if/when water builds up on the land-side of the grouted rip-rap. That could be (is?) a bad thing. So, you'd have to consider weep holes or some other such method to allow equilbration of water pressure.

f-d

¡papá gordo ain’t no madre flaca!