Mohr Circles F 3 F 2 T N V F 4 F 1 H F 5 N Area = sin H T - - PDF document
Mohr Circles F 3 F 2 T N V F 4 F 1 H F 5 N Area = sin H T - - PDF document
Mohr Circles F 3 F 2 T N V F 4 F 1 H F 5 N Area = sin H T Area = cos F H T cos Nsin 0 H F V T sin Ncos 0 V V 1 Area = sin x
F1 F2 F3 F4 F5 H V N T
H V N T Area = sin Area = cos
H V
F H T cos Nsin F V T sin Ncos
y cos 1 1 Area = sin Area = cos
x y
sin cos sin cos sin cos
x sin
x y x y x y
cos2 2 2 sin2 2
Double Angle Formulas
x y
2
x y
2 2
,
Mohr Circle Examples
(32,0) (52,0) (12,0) 35 (39,18.6)
- 20
(52,0) (39,18.6) +15 (32,20)
(6,2) (-4,-2)
1 2 3
Mohr-Coulomb
1 3 ½13) ½13) (ffff) Pole f f
1 3 (ffff) Pole f (ff–ff) –f
+f –f
ff 1 3 Pole f f f
ff 1 3 Pole f f f
ff 1 3 Pole f f f
(ffff) 1 3 Pole ff = c c
Obliquity Relationships
D R
cot c
3 f
1 f
ff
c
Cohesive Soil
1 3 1 3 1 3 1 3
1 2 sin 1 2 cot cot 2
f f f f f f f f
R D c c
Cohesive Soil
D R
3 f
1 f
ff
Cohesionless Soil
1 3 1 3 1 3 1 3
1 2 sin 1 2
f f f f f f f f
R D
Cohesionless Soil
1 2 3
1 sin tan 45 1 sin 2
f f
3 2 1
1 sin tan 45 1 sin 2
f f
Obliquity Relationships
R
Angle of Obliquity
Angle of Obliquity
Example
- A conventional triaxial compression test is conducted on
a medium-dense sandy silt with = 32.
- If the cell pressure (3) is 40 kPa, what is the major
principal stress at failure?
- What is the normal stress on the failure plane at failure?
2 2 1 3 tan
45 40tan 61 130 kPa 2
f f
85 45
ff
Cohesionless Soil
85 45sin 32 61kPa ff
40 130 32°