This chapter discusses effective stress concepts in soil mechanics. It defines total stress, effective stress, and neutral stress and explains how the presence of water affects stress distributions in soils. The chapter aims to explain the differences between stresses in solid materials versus particulate materials like soils. It also discusses capillary phenomena in soils. An exercise problem is provided to calculate total stresses, effective stresses, and pore water pressures at various points in soil profiles and plot how these parameters vary with depth.

1. Chapter VI
Effective stress concept
Specific objectives:
To identify the difference between stresses in a solid material and particulate material.
To identify the effect of presence of water on distribution of stresses in soils.
To understand total stresses, effective and neutral stresses.
To associate capillary phenomenon with soil material.
To be able to work out analytically the implications of these concepts.

2. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
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6. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
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7. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
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8. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
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9. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
Exercise problem
A soil profile is shown in figure. P.5.1. calculate the values of σ,σ' and u at points A, B, C and D. plot the variation
of σ,σ' and u with depth. Use the following data.
Layer no. Thickness in m Unit weight in kN/m3
Profile A
I 1.5 γ d =17.6
II 1.8 γ sat =18.9
III 2.4 γ sat =19.7
Profile B
I 1.5 γ d =15.7
II 3.0 γ d =18.2
III 2.7 γ d =19.2
Ground surface
Layer I Dry sand Ground water table
B
C
Layer II sand
D
Layer III clay
Layer IV Rock
SOIL MECHANICS-I CHAPTER-V EFFECTIVE STRESS CONCEPT 2007-08 MU JAGADEESHA 64

10. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
SOIL MECHANICS-I CHAPTER-V EFFECTIVE STRESS CONCEPT 2007-08 MU JAGADEESHA 65

11. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
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12. HAWASSA UNIVERSITY FACULTY OF TECHNOLOGY CIVIL ENGINEERING DEPARTMENT
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