The document discusses triaxial shear testing of soils. It begins by explaining that soils fail primarily in shear and defining shear strength. It then details the process of a triaxial shear test, including sample preparation and testing stages. The key types of triaxial tests - consolidated drained (CD), consolidated undrained (CU), and unconsolidated undrained (UU) - are explained. Specifically, the document focuses on CD testing, showing how volume change is monitored during shearing and how stress-strain behavior varies with soil density. It also demonstrates how shear strength parameters (c, φ) are determined from CD test results and how the parameters relate to effective stresses and long-term soil behavior analysis.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
shear strength
Angle of repose of sand
Coulomb's law of shear strength
Mohr circle of Stress
Determination of shear strength parameters of soils
Direct shear test
Triaxial Shear Test
Consolidated drained (CD) test
Unconfined Compression Test
Vane shear test
Static Cone Penetrometer Test
Standard Penetration Test (SPT)
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
shear strength
Angle of repose of sand
Coulomb's law of shear strength
Mohr circle of Stress
Determination of shear strength parameters of soils
Direct shear test
Triaxial Shear Test
Consolidated drained (CD) test
Unconfined Compression Test
Vane shear test
Static Cone Penetrometer Test
Standard Penetration Test (SPT)
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Geotechnical Engineering-II [Lec #24: Coulomb EP Theory]Muhammad Irfan
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
DETERMINATION OF UNCONFINED COMPRESSIVE STRENGTH OF SOILJaptyesh Singh
DETERMINATION OF UNCONFINED COMPRESSIVE STRENGTH OF SOIL in Foundation Engineering
INTRODUCTION
TERMINOLOGY
APPARATUS
SOIL SPECIMEN & ITS TYPES
THEORY
RELEVANCE OF THE EXPERIMENT
PROCEDURE
VIDEO
OBSERVATION
DISCUSSION
REMARKS
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Geotechnical Engineering-II [Lec #19: General Bearing Capacity Equation]Muhammad Irfan
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
This presentation is all about Shear Strength of Soil and it's importance in Civil Engineering, application of shear strength, direct shear test, mohr's circle, mohr's coulomb, shear strength, triaxial shear test, unconfined compression test, vane shear test
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Triaxial shear test and shear strength properties of soilsatish dulla
experiments to test the soil strength has given with illstrations. mainly concentrates on the most effective test, triaxial shear test along with brief introdction.
FOR MOVIES
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Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Geotechnical Engineering-II [Lec #24: Coulomb EP Theory]Muhammad Irfan
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
DETERMINATION OF UNCONFINED COMPRESSIVE STRENGTH OF SOILJaptyesh Singh
DETERMINATION OF UNCONFINED COMPRESSIVE STRENGTH OF SOIL in Foundation Engineering
INTRODUCTION
TERMINOLOGY
APPARATUS
SOIL SPECIMEN & ITS TYPES
THEORY
RELEVANCE OF THE EXPERIMENT
PROCEDURE
VIDEO
OBSERVATION
DISCUSSION
REMARKS
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Geotechnical Engineering-II [Lec #19: General Bearing Capacity Equation]Muhammad Irfan
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
This presentation is all about Shear Strength of Soil and it's importance in Civil Engineering, application of shear strength, direct shear test, mohr's circle, mohr's coulomb, shear strength, triaxial shear test, unconfined compression test, vane shear test
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Triaxial shear test and shear strength properties of soilsatish dulla
experiments to test the soil strength has given with illstrations. mainly concentrates on the most effective test, triaxial shear test along with brief introdction.
FOR MOVIES
http://movie-rulz.xyz/category/hollywood-movies/2016-english-movies/
http://movie-rulz.xyz/
http://movie-rulz.xyz/category/telugu-movies/2016-telugu-movies/
Shear Strength of soil and behaviour of soil under shear actionsatish dulla
it contains details of property and theory of soil under shear action.Even the experiments to test the soil strength has given with illstrations
FOR MOVIES
http://movie-rulz.xyz/category/hollywood-movies/2016-english-movies/
http://movie-rulz.xyz/
http://movie-rulz.xyz/category/telugu-movies/2016-telugu-movies/
Geotechnical Engineering-II [Lec #3: Direct Shear Test)Muhammad Irfan
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Similar to Mekanika Tanah - Triaxial shear test (20)
Perhitungan Volume Pekerjaan Rumah Tinggal Tipe 193Reski Aprilia
Sebelum menghitung rancana anggaran biaya ( RAB ) perlu dicari terlebih dahulu berapa volume masing-masing pekerjaan. Berikut cara perhitungan volume pekerjaan rumah tinggal.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
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Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERSveerababupersonal22
It consists of cw radar and fmcw radar ,range measurement,if amplifier and fmcw altimeterThe CW radar operates using continuous wave transmission, while the FMCW radar employs frequency-modulated continuous wave technology. Range measurement is a crucial aspect of radar systems, providing information about the distance to a target. The IF amplifier plays a key role in signal processing, amplifying intermediate frequency signals for further analysis. The FMCW altimeter utilizes frequency-modulated continuous wave technology to accurately measure altitude above a reference point.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
3. Shear failure of soils
Soils generally fail in shear
Embankment
Strip footing
Failure surface
Mobilized shear
resistance
At failure, shear stress along the failure surface
(mobilized shear resistance) reaches the shear strength.
4. Shear failure of soils
Soils generally fail in shear
Retaining
wall
5. Shear failure of soils
Soils generally fail in shear
Retaining
wall
Mobilized
shear
resistance
Failure
surface
At failure, shear stress along the failure surface
(mobilized shear resistance) reaches the shear strength.
8. Mohr-Coulomb Failure Criterion
(in terms of total stresses)
τ
τ f = c + σ tan φ
failu
Cohesio
n
re
τf
c
σ
φ
e
elop
env
Friction
angle
σ
τf is the maximum shear stress the soil can take without
failure, under normal stress of σ.
9. Mohr-Coulomb Failure Criterion
(in terms of effective stresses)
τ
τ f = c'+σ ' tan φ '
re
ailu
f
Effective
cohesion
τf
c’
σ’
e
elop
env
σ ' =σ −u
φ’
u = pore water
pressure
Effective
friction angle
σ’
τf is the maximum shear stress the soil can take without
failure, under normal effective stress of σ’.
10. Mohr-Coulomb Failure Criterion
Shear strength consists of two
components: cohesive and frictional.
τ
τ f = c'+σ ' f tan φ '
τf
φ’
c’
σ’f tan φ’
c’
σ’f
iv
hes
co
t
nen
po
com
e
frictional
component
σ'
c and φ are measures of shear strength.
Higher the values, higher the shear strength.
14. Mohr Circles & Failure Envelope
τ
Failure surface
X
Y
τ f = c'+σ ' tan φ '
X
Y
σ’
Soil elements at different locations
Y ~ stable
X ~ failure
15. Mohr Circles & Failure Envelope
The soil element does not fail if
the Mohr circle is contained
within the envelope
GL
∆σ
σc
Y
σc
σc
Initially, Mohr circle is a point
∆σ
σc+∆σ
16. Mohr Circles & Failure Envelope
As loading progresses, Mohr
circle becomes larger…
GL
σc
Y
∆σ
σc
σc
.. and finally failure occurs
when Mohr circle touches the
envelope
18. Mohr circles in terms of total & effective stresses
σv
X
σ v’
σh
=
X
u
σ h’
+
X
u
τ
effective stresses
σh ’
σv’ σh
total stresses
u
σv
σ or σ’
19. Failure envelopes in terms of total & effective
stresses
σv
X
If X is on
failure
σ v’
σh
τ
=
X
u
σ h’
Failure envelope in terms
of effective stresses
φ’
effective stresses
c’ c
σh ’
σv’ σh
+
X
u
Failure envelope in
terms of total stresses
φ
total stresses
u
σv
σ or σ’
22. Determination of shear strength parameters of
soils (c, φ or c’, φ’)
Laboratory
tests
on
specimens
taken
from
representative undisturbed
samples
Most common laboratory tests
to determine the shear strength
parameters are,
1.Direct shear test
2.Triaxial shear test
Other laboratory tests include,
Direct simple shear test, torsional
ring shear test, plane strain triaxial
test, laboratory vane shear test,
laboratory fall cone test
Field tests
1.
2.
3.
4.
5.
6.
7.
Vane shear test
Torvane
Pocket penetrometer
Fall cone
Pressuremeter
Static cone penetrometer
Standard penetration test
23. Laboratory tests
Field conditions
A representative
soil sample
z
σvc
σhc
σhc
σvc
Before construction
σvc + ∆σ
σhc
σhc
σvc + ∆σ
After and during
construction
z
24. σvc + ∆σ
Laboratory tests
Simulating field conditions
in the laboratory
0
σvc
0
0
0
Representative
soil
sample
taken from the
site
st
e
lt
ia
x
ra
T
Di
σhc rect
sh
ea
r
σhc
σvc
σhc
σvc + ∆σ
σvc
te
τ
st
τ
σvc
Step 1
Set the specimen in
the apparatus and
apply the initial
stress condition
σhc
Step 2
Apply
the
corresponding field
stress conditions
25. Triaxial Shear Test
Piston (to apply deviatoric stress)
Failure plane
O-ring
impervious
membrane
Soil
sample
Soil sample
at failure
Perspex
cell
Porous
stone
Water
Cell pressure
Back pressure
Pore pressure or
pedestal
volume change
28. Triaxial Shear Test
Specimen preparation (undisturbed sample)
Edges of the sample
are carefully trimmed
Setting up the sample
in the triaxial cell
29. Triaxial Shear Test
Specimen preparation (undisturbed sample)
Sample is covered
with
a
rubber
membrane and sealed
Cell is completely
filled with water
30. Triaxial Shear Test
Specimen preparation (undisturbed sample)
Proving ring to
measure
the
deviator load
Dial gauge to
measure vertical
displacement
31. Types of Triaxial Tests
σc
Step 2
Step 1
σc
σc
deviatoric stress
(∆σ = q)
σc
σc
σ c+ q
σc
Under all-around cell pressure σ c
Is the drainage valve open?
yes
Consolidated
sample
no
Shearing (loading)
Is the drainage valve open?
yes
no
Unconsolidated
Drained
Undrained
sample
loading
loading
32. Types of Triaxial Tests
Step 2
Step 1
Under all-around cell pressure σ c
Shearing (loading)
Is the drainage valve open?
yes
Consolidated
sample
Is the drainage valve open?
no
yes
Unconsolidated
no
CD test
Undrained
loading
sample
Drained
loading
UU test
CU test
33. Consolidated- drained test (CD Test)
=
Total, σ
Neutral, u
+
Effective, σ’
Step 1: At the end of consolidation
σ VC
Drainage
σ’VC = σ VC
σ hC
0
σ’hC = σ hC
Step 2: During axial stress increase
σ VC + ∆σ
Drainage
σ hC
σ’V = σ VC +
∆σ = σ’1
0
σ’h = σ hC = σ’3
Step 3: At failure
σ VC + ∆σ f
Drainage
σ hC
σ’Vf = σ VC + ∆σ f = σ’1f
0
σ’hf = σ hC = σ’3f
35. Consolidated- drained test (CD Test)
Expansion
Time
Compression
Volume change of the
sample
Volume change of sample during consolidation
36. Consolidated- drained test (CD Test)
Stress-strain relationship during shearing
d
Dense sand
or OC clay
Expansion a
ro i
t
Compression
Volume change
of the sample
ve D
, ssert s σ ∆
(∆σ d)f
(∆σ d)f
Loose sand
or NC Clay
Axial strain
Dense sand
or OC clay
Axial strain
Loose sand
or NC clay
37. CD tests
How to determine strength parameters c and φ
(∆σ d)f
c
σ 3c
Confining stress = σ 3b
Confining stress = σ 3a
r o a ve D
t i
, ssert s σ ∆
d
Confining stress =
(∆σ d)f
b
σ1 = σ3 +
(∆σ d)f
σ3
(∆σ d)f
a
Axial strain
φ
r ae h S
, ssert s
τ
Mohr – Coulomb
failure envelope
σ 3a
σ 3b σ 3c σ 1a
(∆σ d)f
(∆σ d)fb
σ 1b
σ 1c
σ
or
σ ’
38. CD tests
Strength parameters c and φ obtained from CD tests
Since u = 0 in CD
tests, σ = σ’
Therefore, c = c’
and φ = φ’
cd and φ d are used
to denote them
39. CD tests Failure envelopes
For sand and NC Clay, cd = 0
φd
r ae h S
, ssert s
τ
Mohr – Coulomb
failure envelope
σ 3a
σ 1a
(∆σ d)f
a
σ
or
σ ’
Therefore, one CD test would be sufficient to determine φ d
of sand or NC clay
40. CD tests Failure envelopes
For OC Clay, cd ≠ 0
τ
NC
OC
φ
c
σ3
(∆σ d)f
σ1
σc
σ
or
σ ’
41. Some practical applications of CD analysis for
clays
1. Embankment constructed very slowly, in layers over a soft clay
deposit
Soft clay
τ
τ
= in situ drained
shear strength
42. Some practical applications of CD analysis for
clays
2. Earth dam with steady state seepage
τ
Core
τ
= drained shear
strength of clay core
43. Some practical applications of CD analysis for
clays
3. Excavation or natural slope in clay
τ
τ
= In situ drained shear strength
Note: CD test simulates the long term condition in the field.
Thus, cd and φd should be used to evaluate the long
term behavior of soils
44. Consolidated- Undrained test (CU Test)
=
Total, σ
Neutral, u
+
Effective, σ’
Step 1: At the end of consolidation
σ VC
Drainage
σ’VC = σ VC
σ hC
0
Step 2: During axial stress increase
σ VC + ∆σ
No
drainage
σ hC
±∆
u
Step 3: At failure
σ hC
σ’V = σ VC + ∆σ ± ∆u
= σ’1
σ’h = σ hC ± ∆u
= σ’3
σ’Vf = σ VC + ∆σ f ± ∆uf
= σ’1f
σ VC + ∆σ f
No
drainage
σ’hC = σ hC
±∆uf
σ’hf = σ hC ± ∆uf
= σ’3f
45. Consolidated- Undrained test (CU Test)
Expansion
Time
Compression
Volume change of the
sample
Volume change of sample during consolidation
46. Consolidated- Undrained test (CU Test)
Stress-strain relationship during shearing
d
Dense sand
or OC clay
r t i
+ o a ve D
, ssert s σ ∆
(∆σ d)f
(∆σ d)f
Loose sand
or NC Clay
Axial strain
∆u
Loose
sand /NC
Clay
-
Axial strain
Dense sand
or OC clay
47. CU tests
How to determine strength parameters c and φ
(∆σ d)f
Confining stress =
σ 3a
σ3
(∆σ d)f
a
Total stresses at failure
Axial strain
φ cu
Mohr
–
Coulomb
failure envelope in
terms of total stresses
r ae h S
, ssert s
τ
r o a ve D
t i
, ssert s σ ∆
d
σ 3b
Confining stress =
b
σ1 = σ3 +
(∆σ d)f
ccu
σ 3a
σ 3b
(∆σ d)fa
σ 1a
σ 1b
σ
or
σ ’
48. CU tests
How to determine strength parameters c and φ
σ’1 = σ 3 + (∆σ d)f uf
Mohr – Coulomb failure
envelope in terms of
effective stresses
σ’3 = σ 3 - uf
uf
Effective stresses at failure
φ’
φ cu
r ae h S
, ssert s
τ
Mohr
–
Coulomb
failure envelope in
terms of total stresses
C’
ccu
σ’3b
σ’3a σ 3a
ufa
σ 3b
σ’1a
(∆σ d)fa
ufb
σ’1b
σ 1a
σ 1b
σ
or
σ ’
49. CU tests
Strength parameters c and φ obtained from CD tests
Shear
strength
parameters in terms
of total stresses are
ccu and φ cu
Shear
strength
parameters in terms
of effective stresses
are c’ and φ’
c’ = cd and φ’ =
φd
50. CU tests Failure envelopes
For sand and NC Clay, ccu and c’ = 0
Mohr – Coulomb failure
envelope in terms of
effective stresses
φ’
φ cu
r ae h S
, ssert s
τ
Mohr
–
Coulomb
failure envelope in
terms of total stresses
σ 3a σ 3a
σ 1a σ 1a
(∆σ d)f
σ
or
σ ’
a
Therefore, one CU test would be sufficient to determine
φ cu and φ’(= φ d) of sand or NC clay
51. Some practical applications of CU analysis for
clays
1. Embankment constructed rapidly over a soft clay deposit
Soft clay
τ
τ
= in situ
undrained shear
strength
52. Some practical applications of CU analysis for
clays
2. Rapid drawdown behind an earth dam
τ
Core
τ
= Undrained shear
strength of clay core
53. Some practical applications of CU analysis for
clays
3. Rapid construction of an embankment on a natural slope
τ
τ
= In situ undrained shear strength
Note: Total stress parameters from CU test (ccu and φcu) can be used for
stability problems where,
Soil have become fully consolidated and are at equilibrium with
the existing stress state; Then for some reason additional
stresses are applied quickly with no drainage occurring
54. Unconsolidated- Undrained test (UU Test)
Data analysis
Initial specimen condition
No
drainage
Specimen condition
during shearing
σC = σ3
σC = σ3
No
drainage
σ 3 + ∆σ d
Initial volume of the sample = A0 × H0
Volume of the sample during shearing = A × H
Since the test is conducted under undrained condition,
A × H = A0 × H 0
A ×(H0 – ∆H) = A0 × H0
A ×(1 – ∆H/H0) = A0
A0
A=
1− ε z
σ3
55. Unconsolidated- Undrained test (UU Test)
Step 1: Immediately after sampling
0
0
Step 2: After application of hydrostatic cell pressure
σ’3 = σ 3 - ∆uc
σC = σ3
No
drainage
σC = σ3
=
∆uc
+
σ’3 = σ 3 - ∆uc
∆uc = B ∆σ 3
Increase of pwp due to
increase of cell pressure
Increase of cell pressure
Skempton’s pore water
pressure parameter, B
Note: If soil is fully saturated, then B = 1 (hence, ∆uc = ∆σ 3)
56. Unconsolidated- Undrained test (UU Test)
Step 3: During application of axial load
No
drainage
σ’1 = σ 3 + ∆σ d - ∆uc
σ 3 + ∆σ d
σ3
=
σ’3 = σ 3 - ∆uc
+
∆ud
∆ud
∆uc ± ∆ud
∆ud = A∆σ d
Increase of pwp due to
increase of deviator stress
Increase
stress
Skempton’s pore water
pressure parameter, A
of
deviator
57. Unconsolidated- Undrained test (UU Test)
Combining steps 2 and 3,
∆uc = B ∆σ 3
∆ud = A∆σ d
Total pore water pressure increment at any stage, ∆u
∆u = ∆uc + ∆ud
∆u = B ∆σ 3 + A∆σ d
∆u = B ∆σ 3 + A(∆σ 1 – ∆σ 3)
Skempton’s pore
water pressure
equation
58. Unconsolidated- Undrained test (UU Test)
=
Total, σ
Neutral, u
+
σ’V0 = ur
Step 1: Immediately after sampling
0
0
σ’h0 = ur
-ur
Step 2: After application of hydrostatic cell pressure
No
drainage
σC
σC
-ur + ∆uc =
-ur + σ c
(S = 100% ; B = 1)
r
Step 3: During application of axial load
No
drainage
σ C + ∆σ
σC
-ur + σ c ±
∆u
σ C + ∆σ f
σC
σ’VC = σ C + ur - σ C = ur
σ’h = ur
σ’V = σ C + ∆σ + ur - σ c
∆u
σ’h = σ C + ur - σ c
σ’Vf = σ C + ∆σ f + ur - σ c
Step 3: At failure
No
drainage
Effective, σ’
-ur + σ c ± ∆uf
∆u
∆uf = σ’1f
σ’hf = σ C + ur - σ c
= σ’3f
∆u
f
59. Unconsolidated- Undrained test (UU Test)
=
Total, σ
Neutral, u
σ C + ∆σ f
σC
Effective, σ’
σ’Vf = σ C + ∆σ f + ur - σ c
Step 3: At failure
No
drainage
+
∆uf = σ’1f
σ’hf = σ C + ur - σ c
= σ’3f
-ur + σ c ± ∆uf
∆u
Mohr circle in terms of effective stresses do not depend on the cell
pressure.
Therefore, we get only one Mohr circle in terms of effective stress for
different cell pressures
τ
σ’3
∆σ
σ’1
σ’
f
60. Unconsolidated- Undrained test (UU Test)
=
Total, σ
Neutral, u
σ C + ∆σ f
σC
Effective, σ’
σ’Vf = σ C + ∆σ f + ur - σ c
Step 3: At failure
No
drainage
+
∆uf = σ’1f
σ’hf = σ C + ur - σ c
= σ’3f
-ur + σ c ± ∆uf
∆u
Mohr circles in terms of total stresses
Failure envelope, φ u = 0
τ
cu
ub
σ 3a
σ’3
3b
∆σ f
ua
σ 1a
σ’1
1b
σ or
σ’
f
61. Unconsolidated- Undrained test (UU Test)
Effect of degree of saturation on failure envelope
τ
S < 100%
σ 3c σ 3b
S > 100%
σ 1c σ 3a σ 1b
σ 1a σ or
σ’
62. Some practical applications of UU analysis for
clays
1. Embankment constructed rapidly over a soft clay deposit
Soft clay
τ
τ
= in situ
undrained shear
strength
63. Some practical applications of UU analysis for
clays
2. Large earth dam constructed rapidly with
no change in water content of soft clay
τ
Core
τ
= Undrained shear
strength of clay core
64. Some practical applications of UU analysis for
clays
3. Footing placed rapidly on clay deposit
τ
= In situ undrained shear strength
Note: UU test simulates the short term condition in the field.
Thus, cu can be used to analyze the short term
behavior of soils