Etude des surfaces de rupture

1. Your Footer Here
TRAINING AND RESEACH UNIT
ENGINEERING SCIENCES
IBA DER THIAM UNIVERSITY OF THIES
TYPES OF FAILURE
SURFACE AND CAUSES
PRESENTED BY :
Under The Supervision Of:
Dr. Fatou SAMB

2. CONCLUSION
CAUSES OF FAILURE SURFACE
DEFINITION OF FAILLURE SURFACE
TYPES OF FAILLURE SURFACE
INTRODUCTION
PLAN:
I
II
III

3. Your Footer Here
INTRODUCTION
In geotechnical terms, an earth or soil slope is a
surface of soil mass which is inclined. Slopes can
both occur naturally and be manmade. Failure
surfaces refer to the planes along which materials
or structures break or fail. The type of failure
surface and its causes can vary depending on the
material or structure being considered.

4. Your Footer Here 4
A failure surface is a hypothetical or actual
plane or surface within a material or structure
that experiences mechanical failure or
instability. It is a boundary or interface
between a stable and unstable region, which
can occur due to stress, deformation, or other
physical factors.
I. DEFINITION OF FAILLURE SURFACE
The failure surface may describe the
location, shape, and orientation of
cracks or fractures within a material, or
it may refer to the surface or interface
where deformation and displacement
occur within a structure.

5. II. TYPES OF FAILLURE SURFACE
There are several types of failure surfaces
depending on the material and conditions involved.
Here are some of the most common ones:
Date Your Footer Here 5
PLANE
SURFACE CIRCULAR
SURFACE
COMPLEXE
SURFACE

6. Date Your Footer Here 6
 This type of failure can be observed in
slopes of layered materials or natural slope
formations.
The favorable conditions of plane failure
are as follows:
The dip direction of the planar
discontinuity must be within (+ 20°) of the
dip direction of the slope face.
a. PLANE FAILURE
The dip of the planar discontinuity must be less than
the dip of the slope face.
The dip of the planar discontinuity must be greater

7. Date Your Footer Here 7
 In the case of rotational failure, the
failure occurs by rotation along a slip
surface and the shape thus obtained in slip
surface is curved. Failed surface moves
outwards and downwards.
CIRCULAR FAILURE SURFACE
In homogeneous soils, the shape is circular
while in case of non-homogeneous soils it is
non-circular..

8. Date Your Footer Here 8
c. SURFACE OF COMPOND FAILURE
 A Compound failure is a
combination of translational slide
and rotational slide.
In this case, the slip surface is curved at two ends like rotational
slip surface and flat at central portion like in translational failure.
The slip surface becomes flat whenever there is a hard soil layer at
a considerable depth from toe.

9. Date Your Footer Here 9
The causes of failure surfaces can vary depending on the type of
material or structure involved.
However, some common causes of failure surfaces include:
• NATURAL SOIL STRENGHT
• ADITIONAL SOIL CHARGES
• SOIL CHANGES
• SOIL CARACTEISTICS
• HUMAN ACTIVITIES
III. CAUSES OF FAILURE SURFACE

10. Date Your Footer Here 10
Natural soil strength refers to the ability of soil to resist deformation
and failure under various loads and stresses. Soil strength is an
important factor in determining the suitability of a site for
construction and engineering projects.
The strength of soil is influenced by various factors
• soil composition,
• moisture content,
• compaction,
• and temperature
Natural soil strength

11. Date Your Footer Here 11
Soil strength can be measured through various tests:
• the triaxial test,
• unconfined compression test,
• direct shear test
Factors that can affect natural soil strength:
• weathering,
• erosion,
• changes in soil moisture content due to rainfall or irrigation.
In addition, natural soil strength can be enhanced through
techniques such as soil stabilization, which involves adding
materials such as cement, lime, or fly ash to improve the strength
and stability of the soil.
Natural soil strength

12. Date Your Footer Here 12
Additional soil loads refer to extra weight or pressure that may be placed on
the soil at a construction site.
• Heavy equipment
• Underground utilities
• Increased building height or size
• Soil erosion
It is important to consider potential additional soil loads during the project
design and planning phase to ensure that the soil can adequately support the
weight and pressure of the construction project. Proper soil testing, analysis,
and preparation can help to mitigate the risks associated with additional soil
loads.
Additional soil loads

13. Date Your Footer Here 13
Soil changes refer to alterations in the physical, chemical, or biological
properties of the soil. These changes can be natural or human-induced
and can have significant impacts on soil fertility, water retention, and
ecosystem health.
• Soil erosion
• Soil compaction
• Soil pollution
• Soil acidification
• Soil salinization
Soil changes

14. Date Your Footer Here 14
Soil erosion
Soil erosion is the natural
process by which soil is
carried away by water or
wind. However, human
activities such as
deforestation, agriculture,
and construction can
accelerate soil erosion,
leading to soil depletion
and reduced soil quality.

15. Date Your Footer Here 15
Soil compaction
Soil compaction occurs
when the soil is
compressed, reducing pore
space and limiting the
movement of air, water,
and nutrients. This can
result in decreased soil
fertility and decreased
plant growth.

16. Date Your Footer Here 16
Soil pollution
Soil pollution occurs when
contaminants such as
heavy metals, pesticides, or
industrial waste are
introduced to the soil. This
can have adverse effects on
soil quality, plant growth,
and human health.

17. Date Your Footer Here 17
Soil acidification
Soil acidification occurs
when the pH of the soil
decreases, often as a result
of human activities such as
excessive fertilizer use or
acid rain. This can lead to
decreased soil fertility and
plant growth.

18. Date Your Footer Here 18
Soil salinization
Soil salinization occurs
when the concentration of
salts in the soil increases,
often as a result of
irrigation or poor drainage.
This can lead to decreased
soil fertility and decreased
plant growth.

19. Made with by
Thank You !
FOR YOUR ATTENTION