Mohr-Coulomb Failure Criteria - 2 | 11. Factors Influencing Shear Strength | Geotechnical Engineering - Vol 2
K12 Students

Academics

AI-Powered learning for Grades 8–12, aligned with major Indian and international curricula.

Professionals

Professional Courses

Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.

Games

Interactive Games

Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.

2 - Mohr-Coulomb Failure Criteria

Enroll to start learning

You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.

Practice

Interactive Audio Lesson

Listen to a student-teacher conversation explaining the topic in a relatable way.

Understanding Shear Strength

Unlock Audio Lesson

0:00
Teacher
Teacher

So, let’s start with shear strength. Can anyone tell me what factors might influence this?

Student 1
Student 1

Is it just the type of soil?

Teacher
Teacher

Great start! Soil composition plays a major role, including mineralogy, grain size, and even pore fluid content. Remember the acronym MGP for 'Mineralogy, Grain size, Pore fluid'!

Student 2
Student 2

What about the way the soil is arranged?

Teacher
Teacher

Exactly! The structure of the soil, which includes how the particles are arranged and packed, also influences shear strength. We can think of 'S' for structure in our MGP acronym.

Student 3
Student 3

So all these factors work together?

Teacher
Teacher

Exactly! The interplay of these components defines the soil's stability under stress. To summarize, shear strength is influenced by composition, initial state, and structure.

Introduction to Mohr-Coulomb Failure Criteria

Unlock Audio Lesson

0:00
Teacher
Teacher

Now, let’s move to the Mohr-Coulomb Failure Criteria. What do you think it signifies?

Student 4
Student 4

Does it have to do with when a material fails?

Teacher
Teacher

Correct! It states that failure occurs due to a critical combination of normal stress and shear stress. It’s not just about the maximum values of each.

Student 1
Student 1

So they have to work together?

Teacher
Teacher

Precisely! Think of it as a balancing act. If one exceeds its limits without considering the other, failure might not occur. A good way to remember this is by thinking of them as dance partners—each must adjust to the other's movements.

Student 3
Student 3

Can this help in predicting soil failure?

Teacher
Teacher

Yes! By analyzing the stresses involved, we can predict failure more accurately. So to summarize, the Mohr-Coulomb criteria focuses on the interplay between normal and shear stresses.

Real-World Applications

Unlock Audio Lesson

0:00
Teacher
Teacher

Let’s look at real-world problems. Can anyone think of a scenario where understanding these principles is vital?

Student 2
Student 2

Maybe in civil engineering when building roads?

Teacher
Teacher

Spot on! Engineers must understand shear strength to design safe structures. Improper calculations could lead to a catastrophic failure.

Student 4
Student 4

So, this theory is really important in construction?

Teacher
Teacher

Absolutely! It helps in assessing the stability of slopes, retaining walls, and foundations. Let’s summarize: Mohr-Coulomb helps predict when structures might fail, particularly under loading conditions.

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

The Mohr-Coulomb Failure Criteria explains the conditions under which materials fail due to the interplay between normal stress and shear stress.

Standard

This section outlines the factors influencing shear strength, including soil composition, initial state, and structure. It introduces the Mohr-Coulomb Failure Criteria, which posits that failure occurs at a critical combination of normal and shear stresses rather than exceeding their maximums.

Detailed

The Mohr-Coulomb Failure Criteria plays a crucial role in understanding soil mechanics and materials failure. It asserts that a material's failure results from a specific balance of normal and shear stress rather than merely their peak values. Factors such as soil composition (including mineralogy and grain size), the initial state of the soil (e.g., loose or dense), and the structure (particle arrangement and packing) influence shear strength. By examining these elements, one can better predict when and how a material may fail under stress.

Youtube Videos

Lecture 9.2: Mohr-Coulomb Failure Criterion
Lecture 9.2: Mohr-Coulomb Failure Criterion
Mohr Coulomb's Theory of Shear Strength | Lecture 31 | Geotechnical Engineering
Mohr Coulomb's Theory of Shear Strength | Lecture 31 | Geotechnical Engineering
Mohr Coulomb's Theory of Shear Strength In Hindi | Soil Mechanics
Mohr Coulomb's Theory of Shear Strength In Hindi | Soil Mechanics
soil liquefaction- mohr-coulomb failure criterion
soil liquefaction- mohr-coulomb failure criterion
Using Mohr-Coulomb Failure Criteria for Rocks in Engineering | Triaxial Tests Data Analysis
Using Mohr-Coulomb Failure Criteria for Rocks in Engineering | Triaxial Tests Data Analysis
Why Landslides happen? | Shear Strength of Soil | Mohr - Coulomb Theory | Elementary Engineering
Why Landslides happen? | Shear Strength of Soil | Mohr - Coulomb Theory | Elementary Engineering
Lecture 28: Mohr-Coulomb Failure Criterion
Lecture 28: Mohr-Coulomb Failure Criterion
Chapter 12 Shear Strength of Soil - 3. Mohr-Coulomb Failure Criterion
Chapter 12 Shear Strength of Soil - 3. Mohr-Coulomb Failure Criterion
Geotechnical Engineering: Lecture 4: Mohr Coulomb Theory
Geotechnical Engineering: Lecture 4: Mohr Coulomb Theory
24 shear strength of soils - Mohr-Coulomb failure criteria & Direct shear test (PPT)
24 shear strength of soils - Mohr-Coulomb failure criteria & Direct shear test (PPT)

Audio Book

Dive deep into the subject with an immersive audiobook experience.

Introduction to the Mohr-Coulomb Failure Criteria

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

This theory states that a material fails because of a critical combination of normal stress and shear stress, and not from their either maximum normal or shear stress alone.

Detailed Explanation

The Mohr-Coulomb Failure Criteria posits that material failure occurs due to a specific relationship between two types of stress: normal stress and shear stress. Normal stress acts perpendicular to a surface, while shear stress acts parallel to it. The key point here is that it is the combination of these stresses that leads to failure, rather than the individual effects of maximum normal or shear stresses. This means that understanding how these stresses interact is crucial for predicting when a material will fail.

Examples & Analogies

Imagine trying to push a large box across a rough floor. The effort you apply to push it sideways (shear stress) and the weight of the box pressing down on the floor (normal stress) must work together. If you push too hard without addressing the weight, the box may not move. Conversely, if it’s too heavy, it’ll resist your push. Only when you consider both forces together can you predict whether the box will slide or stay put, much like how soil or rock fails under stress.

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • Shear Strength: The resistance of soil to shearing forces related to its composition and structure.

  • Mohr-Coulomb Failure Criteria: A framework for understanding when materials will fail under stress, emphasizing the interaction of normal and shear stress.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • A slope failure in a hillside due to excessive rain increases pore water pressure, reducing shear strength below the critical combination of stresses.

  • In foundation engineering, the Mohr-Coulomb criteria are applied to ensure that foundational structures can bear the expected loads without failing.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎵 Rhymes Time

  • In soil and stress, we must invest, to prevent a fail we must balance the rest.

📖 Fascinating Stories

  • Imagine two dancers on a stage; if one leans too far without regard to the other, they will both fall. This is like the balance needed between normal and shear stress.

🧠 Other Memory Gems

  • Memory aid for shear strength: MGP = Mineralogy, Grain size, Pore fluid.

🎯 Super Acronyms

S for Structure helps to remember that soil arrangement influences shear strength.

Flash Cards

Review key concepts with flashcards.

Glossary of Terms

Review the Definitions for terms.

  • Term: Shear Strength

    Definition:

    The resistance of a material to shear forces, influenced by various factors like composition, state, and structure.

  • Term: MohrCoulomb Failure Criteria

    Definition:

    A theory stating that a material fails under a critical combination of normal stress and shear stress.

  • Term: Soil Composition

    Definition:

    The makeup of soil, including mineralogy, grain size, and pore fluid characteristics.

  • Term: Soil Structure

    Definition:

    The arrangement and organization of soil particles within a mass.

  • Term: Normal Stress

    Definition:

    The stress acting perpendicular to a given surface.

  • Term: Shear Stress

    Definition:

    The stress acting parallel to a given surface.