lecture 1_introduction - phase diagram

7/27/2019 Lecture 1_Introduction - Phase Diagram

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PBWN302

CEM/WEE/STE

Dr.Asmaa

Moddather

SoilMechanicsandFoundations

FacultyofEngineering CairoUniversity


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e ne: oy Naturally occuring particulate material

y orme , rect y or n rect y, rom so roc s .e.weathering)

y Composition of soil particles depends on

y The void space between the particles contain water

an or air

Dr.Asmaa Moddather PBWN302 Fall2012


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pp cat ons

y EngineerusestheSOILtobuild:

. .

y Init:e.g.tunnels

y Withit;e.g.earthdams



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xamp e: r ge oun at ons



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xamp e: unne



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xamp e: art am



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ourse ut ney Introduction

y Phasediagram

y o ass cat on

y

y Stresses

y Consolidation

y ShearStrength



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PBWN302 Soi Mec anics

Fall2012

y Instructor: Dr.AsmaaModdather .

y Lectures: Tuesday10:00am 12:00am,Classroom:20103

y

Tutorials:Thursday03:00pm 06:00pm,Classroom:20507

y Textbook: Das, B.M. (2008), Introduction to GeotechnicalEngineering, Thomson Learning, Toronto, Ontario, Canada.

y Objectives: The purpose of this course is to familiarize.

on describing the nature and behavior of soils.



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Fall2012

y Grading: AttendanceandClassParticipation 10%

Assignments 10%

Quizzes 20%MidtermExam 20%

FinalExam 40%



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Fall2012

y Assignments:

y

ere w e approx mate y seven 7 ass gnments.y Assignments shall be handed out in the tutorial sessions.

y ss gnmen s mus e su m e n person e weefollowing end of class discussion of the topic.

y .

y No excuses shall be given for late submittals without awritten re uest and a roval.

y Quizzes: Therewillbeapproximatelyseven(7)quizzes.

y Exams: Onemidtermwillbegivenduringthesemester.


Afinalexamwillbegiveninthescheduledfinalexamperiod.


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PBWN302 SoilMechanics

Fall2012

Web Site:

www.egypteducation.org

Course:

Soil

Mechanics

Fall2012

Home Courses CairoUniversity FacultyofEngineering

SoilMechanics

Fall

2012

Enrol.Key:

PBWN302



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e n t ons

y Soil: is any accumulation of mineral particles formed by the

weathering of rocks, the void space between the particles containing

.

y Soil Mechanics: is the branch of science dealing with the study of

the physical properties of soil and the behavior of soil masses subjectedto various t es of forces



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o ormat ony Residual soil: the products of rock weathering remain at their

original location.

y

a different location. (gravity, wind, water)



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o ormat ony Weathering bymechanicalor chemicalprocesses

y

Mechanical by contraction and expansion of rock, erosion by wind orwater: resultant soil is bulky, angular, rounded, elongated, f lat.



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o ormat ony Chemical: results in changes in the mineral form of the parent rock

due to the action of water, oxygen, and carbon dioxide.

y Chemical weathering results in the formation of groups of crystalline

.



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o ormat ony Mostclaymineralparticlesareofplatelike

Dispersed Flocculated



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o o umesan e g ts e at ons pParticles(solids)

Air

Water

Solid

Phase

dia ramSoil

sam leVoids Air

(dry

soil)

water(saturatedsoil)


Air/water(wetsoil)


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ase agram

Air

Water

Solid

Wei htsVolumes



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ase agramVs =Volumeofsolids

V

=volumeofvoids

Vw =volumeofwater

a

VT =totalvolume=Vs +Vw+ Va =Vs +Vv

Ws =weightofsolidsAir

Ww =weightofwater

Wa =weightofair=0

Water

W =totalwei ht=W+W

Solid


e g tsVolumes


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ase agramw =Densityofwater=1.0t/m

3=1.0gm/cm3 =10.0kN/m3

w w w

Ww =wVw

s =Densityofsolids=Ws/Vs =2.5 2.8t/m3

s= = s w

Air

s =s s= sw s

Water

ex., s =2.70 m

Gs =2.70/1.0=2.70

o


ex., s =26.5kN/m3

Gs =26.5/10.0=2.65


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ase agramRatios:

e =void

ratio

=

Coulde beequaltozero? No

Coulde be

e ual

to

1.0?

Yes

Air

Coulde begreaterthan1.0? Yesater

S=degree

of

saturation

=

o

CouldS beequaltozero? Yes


Cou

S eequa

to

1.0?

es

CouldS begreaterthan1.0? No


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ase agramRatios:

n=porosity=

Couldn be

equal

to

zero?

No Air

Couldn beequalto1.0? No

Couldn be reaterthan1.0? NoWater

= =Solid

Couldwbeequaltozero? Yes

WeightsVolumes


.

Couldwbegreaterthan1.0?Yes


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ase agramAir

Densities:

Water

d =dry

unit

weight

=

Solid

wet =

wet

(bulk)

unit

weight

=

=

e g so umes

wsWW +

T

sat =saturate unitweig t=T

vws

V

sub =submergedunitweight=sat w



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Howtomeasuresoilwatercontent?

1. Getthetotalwei htofsoilsam le=W

2. Ovendry

the

sample,

then

weigh

=Ws

. Calculate: sTwWWW

w

==

ss

1. Submergingthesampleincontainerfullofmercury.Measureweightofdisplacedmercury(Wmercur ). VT =Wmercur /mercur

2. Coverthesamplewithwax,thensubmergeitincontainerfullofwater.Measureweightofdisplacedwater(Ww). VT +Vwax =Ww/w.Then eelthewax,and etW ,andcalculateV =W / .Thus et


VT.


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. , s, .

AssumeWs =1

1w

s

w

W

W

Ww ==

Air

w/wS

Water ww/ws

s

s

V=

s

s

sV

=

Solid 11/Gswws

=

wssG =

sW

V1

==

WeightsVolumes

w

w

wWV ==

wsws

s

GG

w

w

W=

ww

w

wV

S =w

v

wVV == Cangete,n,d


v w


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. , s, . , , dAssumeVs =1

1v

s

v

V

V

V

e ==Air

e

Water weSeSeSSVV vw ==v

w

V

VS =

Solid Gsw1eSVW

wwww ==

GVW ==

WeightsVolumesCan

get

w,

n,

d


lecture 1_introduction - phase diagram

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