BuyFindarrow_forward

Principles of Geotechnical Enginee...

9th Edition
Braja M. Das + 1 other
ISBN: 9781305970939

Solutions

Chapter
Section
BuyFindarrow_forward

Principles of Geotechnical Enginee...

9th Edition
Braja M. Das + 1 other
ISBN: 9781305970939
Textbook Problem

Determine the minimum factor of safety of a slope with the following parameters: H = 90 ft, β = 26.56° (2:1 slope), γ = 122.5 lb/ft3, ϕ' = 30°, c' = 568 lb/ft2, and ru = 0.5. Use Bishop and Morgenstern’s method.

To determine

Find the minimum factor of safety Fs using the Bishop and Morgenstern’s method.

Explanation

Given information:

The height (H) of the slope is 90 ft.

The inclination β of a slope (2:1slope) is 26.56°.

The unit weight γ is 122.5lb/ft3.

The angle of friction ϕ is 30°.

The cohesion c is 568lb/ft2.

The value non-dimensional quantity ru is 0.5.

Calculation:

To determine the minimum factor of safety Fs from Table (15.5), the following procedure must be followed.

  • Step 1. Obtain the values of angle of friction, inclination of a slope, and the value of cγH.
  • Step 2. Obtain the value of nondimensional quantity.
  • Step 3. Refer Table (15.5) “Values of m and n for cγH=0” in the text book. Obtain the values of m and n for D=1,1.25,and1.5.
  • Step 4. Then calculate the factor of safety value, using the values of m and n for each value of D.
  • Finally, the required value of factor of safety is the smallest one obtained in step 4.

Determine the value of cγH.

Substitute 568lb/ft2 for c, 122.5lb/ft3 for γ, and 90 ft for H.

cγH=568122.5(90)=0.05

Determine the factor of safety using the formula.

Fs=mnru (1)

Consider D=1m:

Refer Table (15.5d) “Stability coefficients m and n for cγH=0.05 and D=1.00” in the text book.

Take the stability coefficient m as 1.888 when the angle of friction ϕ is 30°

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Additional Engineering Solutions

Find more solutions based on key concepts

Show solutions add

What are the main ingredients of concrete?

Engineering Fundamentals: An Introduction to Engineering (MindTap Course List)

What two functions can the lathe tailstock perform?

Precision Machining Technology (MindTap Course List)

Solid Waste Engineering

What are main steps in the software acquisition process?

Systems Analysis and Design (Shelly Cashman Series) (MindTap Course List)

What does access time measure? (371)

Enhanced Discovering Computers 2017 (Shelly Cashman Series) (MindTap Course List)

What is the purpose of preheating metal before it is welded?

Welding: Principles and Applications (MindTap Course List)