lec 01 1 shear strength -...
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CIE3032 지반공학및실험 Lecture 01 shear strength 1
LECTURE 01
Shear strength of soils
CIE3032 지반공학및실험 Lecture 01 shear strength 2
Lecture outline
State of Stress / Strain
Elastic Stress – Strain Relationship
Shear Strength: Mohr-Coulomb Failure Criteria
Stress Path
CIE3032 지반공학및실험 Lecture 01 shear strength 3
Lecture outline
Laboratory tests to measure shear strengthDirect shear testSimple shear testTriaxial testState of stress – strain of laboratory tests
Shear Behavior and Strength of Sands
Shear Behavior and Strength of Clays
CIE3032 지반공학및실험 Lecture 01 shear strength 4
Review of Soil Mechanics – Stress Components
CIE3032 지반공학및실험 Lecture 01 shear strength 5
Review of Soil Mechanics – Stress Components
CIE3032 지반공학및실험 Lecture 01 shear strength 6
2D Stress & Mohr Circle
vh
v
h
Sign Convention:Normal Stress+ Compression
CIE3032 지반공학및실험 Lecture 01 shear strength 7
Mohr Circle – Change in shape
vh
v
h
Sign Convention:Normal Stress+ Compression
v
v
CIE3032 지반공학및실험 Lecture 01 shear strength 8
Mohr Circle - Example
The soil sample is subjected to equal-all-around hydrostatic pressure of 10 kPa. Draw the Mohr circle.
Determine principal stressDetermine maximum shear stress
The axial stress is increased to 70 kPa. Draw the Mohr circle.Determine maximum deviatoric stressDetermine maximum shear stress
CIE3032 지반공학및실험 Lecture 01 shear strength 9
2D Stress & Mohr Circle
13
v1
1
h
If v > h
v 1
h 1
Sign Convention:Normal Stress+ Compression
Shear Stress+ Clock-wise
+
CIE3032 지반공학및실험 Lecture 01 shear strength 10
Mohr Circle - Example
A shear stress of 40 KPa is applied at the vertical and horizontal boundaries. Plot the Mohr circle.
Determine maximum shear stressDetermine plane(s) of maximum shear stressDetermine major and minor principal stressesDetermine principal planesDetermine stresses acting on planes inclined 10° from the horizontal planeDetermine stresses acting on planes inclined 10° from the vertical plane
CIE3032 지반공학및실험 Lecture 01 shear strength 11
State of Stress – Mohr Circle - Pole Method
kPa)
kPa)
계산 순서:1. 기준면 선택2. Pole (극점) 계산3. 구하고자 하는 면 도시응력 계산
CIE3032 지반공학및실험 Lecture 01 shear strength 12
Calculate stresses at a plane
13
2
1v
1
1
h
If v > h
v 1
h 1
Sign Convention:Normal Stress+ Compression
Shear Stress+ Clock-wise
CIE3032 지반공학및실험 Lecture 01 shear strength 13
Total vs. Effective Stress
CIE3032 지반공학및실험 Lecture 01 shear strength 14
Stress
CIE3032 지반공학및실험 Lecture 01 shear strength 15
Effective Stress & PWP
CIE3032 지반공학및실험 Lecture 01 shear strength 16
Stress PathAn effective way to represent the loading / unloading in soil
p, p’, q: can be expressed either in total or effective stressESP: Effective stress pathTSP: Total stress path
CIE3032 지반공학및실험 Lecture 01 shear strength 17
Drained Stress Path Calculation Example 1
p’
q
Initial conditionv‘=50 kPah‘=50 kPa
Applied condition1) v’ = 50kPa, h’ = 02) h’ = 50kPa, v’ = 03) v’ = -50kPa, h’ = 04) h’ = -50kPa, v’ = 0