Shear strength

[GeoMax001]

Hi,

I have these results shown below of three different soils,

Soil 1 -> LL = 44 / PL = 18
Soil 2 -> LL = 56 / PL = 22
Soil 3 -> LL = 96 / PL = 24

Is the shear strength the same for all three soils at their respective liquid limit value?

Thanks,

 

[fattdad]

what's the natural moisture content?

f-d

¡papá gordo ain’t no madre flaca!

 

[GeoPaveTraffic]

Drained or undrained shear strength?

Mike Lambert

 

[fattdad]

Oh yeah, Also, what's the depositional environment? I mean is there any likelihood that the soil is sensitive (i.e., from an marine depositional environment)?

f-d

¡papá gordo ain’t no madre flaca!

 

[aeoliantexan]

OK, if this is a joke, I'll be the one to bite. At the liquid limit, a clay is by definition beginning to behave as a liquid, which has a static shear strength of zero, or at least darned small. So yes, in a remolded state, they all have the same shear strength - NONE.

In an undisturbed, undrained condition, if the soil is sensitive, it can have quite a bit of strength, but I don't know how to predict it from the data given. Stress history is probably needed. However, for a given value of preconsolidation pressure, the undrained strength increases both with increasing PI and with increasing LL.

In a drained condition, I would expect the clays with higher PI to display lower friction angle.