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6
The vertical total stress
σ
v
= 19.99kN/m
3
×
0.4245m =
8.486kPa. Hence the vertical
effective stress
'
v
=
v
 u = 8.486kPa  4.164kPa
⇒
'
v
= 4.322kPa
(c) In the dense, saturated state, the weights of water and soil grains above the base do not
change. Hence the pore water pressure and the total stress are the same as before, and so
also is the effective stress:
u = 4.164 kPa;
'
v
= 4.322kPa
(d) The water level in the column does not change: as the sand is densified, it settles through
the water. The new sample height h' is given by its volume, 1130cm
3
, divided by the cross
sectional area of the measuring cylinder, 28.27cm
2
, giving h' = 39.972cm. The depth of water
above the new sample surface is therefore (42.448cm  39.972cm) = 2.476cm. The pore water
pressure at the new soil surface is 9.81kN/m
3
0.02476m
u = 0.243kPa
The effective stress at the sand surface is zero.
Particle size analysis and soil filters
Q1.6
A sieve analysis on a sample of initial total mass 294g gave the following results:
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This note was uploaded on 12/28/2011 for the course CHM 4302 taught by Professor Stuartchalk during the Fall '11 term at UNF.
 Fall '11
 StuartChalk
 Analytical Chemistry

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