Draw the planes 450 to horizontal
Normal and shear stresses for this two planes can be determined by
coordinates of point E and F
One possible practical application of this Mohr Circle analysis:
reading the

Note that in this case sv s1 and sh s3, one possible situation:
Draw both principal planes (with t = 0)
Magnitude and inclination of both principal stresses can be determined
Draw the two planes of max. shear (i.e. top and bottom of circle)
Magnitude and

Plot point M representing the normal and shear of the minor principal
stress (s3 = 15 kPa and t = 0)
Plot point N representing the normal and shear of the major principal
stress (s1 = 45 kPa and t = 0)
Construct the Mohr circle using MN as diameter
Draw

How to locate the pole of a Mohr Circle?
Point A on the circle representing1. Normal stress (x-axis) acting 90o to the inclined plane
2. Shear stress (y-axis) acting along the inclined plane
3. The orientation (30o) of the inclined plane
More Example on M

Summary (Excavation)
For a saturated clay, the above excavation example suggested the stability of the
cutting is best immediately after excavation, but will deteriorate in the long-term.
Critical stage for design = long-term
Stress-in-ground example
What

Problem Solving Exercise on Soil Stability
(Stress Analysis and Shear Strength)
t = 0 along vertical (minor principal) and horizontal (major principal) planes
Pore pressure distribution due to capillary effect (note suction above water table)

Effective stress Mohr circle (short-term)
Change in Effective Stresses with time (i.e. with drainage taking place gradually)
Embankment - with drainage occurring
Summary (Embankment)
For a saturated clay, the above embankment example suggested the stabili

EXCAVATION
Consider Short-Term after Excavation
(i.e. soil still in an undrained situation)
Short-term after Excavation
Note there was a reduction in pore water pressure = -15 KPa as measured in the field.
This additional suction was caused by:
1. The ten

Consider Short-Term after Embankment (i.e. soil still in an undrained situation)
Short-term after Embankment
Note there was a increase in pore water pressure = +35 KPa as measured in the field.
This additional pressure was caused by:
1. The tendency of th

Consider all Stresses
Prior to
Construction Activities
Before Any Construction Activities
At Z = 2m
ui
= suction due to capillary
= - rw g h = - (1000)(9.8)(2) = -19 600 pa = -20 kPa
(sv)i
= overburden stress
= rsat g z = (1800)(9.8)(2) = 35 280 pa = 35 k

Answer to (b):
Draw the two lines represent t = + s tan 450
Since the two lines do not touch the Mohr Circle,
no such relationship holds
More Example on Mohr Circle Given:
Stress condition of a soil element as shown
To determine:
(i)
Direction of principa