1. In carrying out a UU test on saturated clay, what is the significance of confining pressure. 2. What the is the confining pressure one should apply in testing for Unconsolidated undrained test. (Is it the total overburden pressure or the effectiveoverburden pressure. 3. Does the free standing water depth affect the confining pressure to be applied. 4. What is the effective stress at a point H belowmudline for the following a. With zero free standing water depth b. with a free standing water of Z (from water levelto soil)
Best to avoid the UU altogether as UU = useless, unreliable. Sure, its an easy test to run, but gives scattered results that make it impossible to utilize in a strength analysis. See Terzaghi Lecture by Chuck Ladd (1991, ASCE Journal of Geotech Engrg.). If you run a CIUC test, you will benefit from getting info on the effective stress strength envelope (effective friction angle = phi') plus some info on total stress parameter (su = undrained shear strength). The latter will be too high a mode for general strength, but you can reduce to an equivalent "average" or "representative" direct simple shear strength by method of Kulhawy (Predictive Soil Mechanics, 1993, Thomas Telford) or taking 2/3 value to reduce from CIUC to DSS.
On the effective stresses below the mudline, both the total overburden & the hydrostatic increase by same amount, so the effective overburden (vertical) stress remains the same.