Tresca Model

1. CRITICAL STATE SOIL MECHANICS
TRESCA MODEL (MAX. SHEAR STRESS THEORY)
1. Rameez Riyaz (2021MCIVGT006)
2. Eiqan Shafi (2021MCIVGT017)
3. Shahid Manzoor Bhat (2021MCIVGT002)

2. INTRODUCTION
Failure occurs when material starts exhibiting inelastic behavior
Brittle and Ductile materials have different modes of failure
Ductile materials exhibit yielding or plastic deformation before failure
Yield stree is the property of the material
No yielding occurs in Brittle materials.There is a sudden failure

3. FAILURE THEORY MODELS
 Mohr – Coulomb Model
 Hardening Soil Model / Hardening Mohr – Coulomb Model
 Modified Cam – Clay Model
 Drucker – Prager Model
 Tresca Model
 Hoek – Brown Model
 Duncan – Chang Model

4. TRESCA MODEL (MAX. SHEAR STRESSTHEORY)
Failure occurs when maximum shear stress in a complex stress system equals to the
maximum shear stress at yield point under uniaxial loading.
No failure occurs if maximum shear <Y/2

5. PURE SHEAR CASE
ShearYield = 0.5x TensileYield

6. 3D STRESS STATE
In 3D stress state, principal stresses are =>
• Maximum shear stress:
• Yield
function:

7. Yield function in Principal stress space

8. Tresca hexagon

9. 2D STRESS
STATE
EACH EQUATION REPRESENTS
TWO LINES IN 2D STRESS SPACE

10. CONCLUSION
 This theory is suitable for ductile materials
 For pure shear case it is oversafe
Limitations
 Not applicable for materials subjected to hydrostatic
loading as it says shear stress will be zero and material
will never fail which is practically impossible
 Not applicable for brittle materials as they have
different yield stress in tension and compression

11. THANKYOU