KLASIFIKASI TANAH -...
Transcript of KLASIFIKASI TANAH -...
KLASIFIKASI TANAH
PENGERTIAN TENTANG TANAH
• UKURAN PARTIKEL
BERUKURAN BESAR : quartz , feldspar
BERUKURAN SANGAT LEMBUT : clay minerals
• RONGGA DIANTARA PARTIKEL DIISI UDARA/AIR
Aragonite-rich soil x 2000
Cemented calcareous sand
KLASIFIKASI YANG DIDASARKAN TEKSTUR / UKURAN DAN
PERMUKAAN BUTIRAN
• UKURAN PARTIKEL BIASANYA DIKAITKAN DENGAN KANDUNGAN MINERALNYA, CONTOH DENGAN KANDUNGAN MINERALNYA, CONTOH Ukuran partikel kecil, biasanya mengandungCLAY
BEBERAPA STANDART KLASIFIKASI TANAH
• UNITED STATE DEPARTEMENT of AGRICULTURE(USDA)
• AMERICAN ASOSIATION of STATE HIGWAY and TRANSPORTATION OFFICIAL ( AASHTO )TRANSPORTATION OFFICIAL ( AASHTO )
• UNIFIED SOIL CLASIFICATION SYSTEM (USCS)
PROSEDUR ANALISA UKURAN BUTIR
• Analisa dengan ayakan dipakai untuk ukuran partikel > 75 µm
• Analisa Hydrometer dipakai untuk butiran lembutYakni analisa yang didasarkan Hukum Stoke’s , dimana kecepatan mengendap butiran dianggap proporsional terhadap diameter butiran
KURVA UKURAN BUTIR
2 0
4 0
6 0
8 0
1 0 0%
Fin
er
0 .0 0 0 1 0 .0 0 1 0 .0 1 0 .1 1 1 0 1 0 00
2 0
P ar tic le s ize (mm)
W Well graded
U Uniform
P Poorly graded
C Well graded with some clay
F Well graded with an excess of fines
• CONTOH 1
• TANAH A TERDIRI DARI ;• PASIR ; 30 %• LANAU ; 30 %• LEMPUNG ; 40 % ( BUTIRAN < 0,002 mm )• Plotkan dalam grafik ; Jenis tanah LEMPUNG TANAH LIAT
• CONTOH 2• TANAH A TSB MENGANDUNG KERIKIL 20 % DAN • TANAH A TSB MENGANDUNG KERIKIL 20 % DAN
PASIR 10 %MAKA HARUS DIADAKAN KOREKSI
%5020100
10040;
%5,3720100
10030;
%5,1220100
10010;
=−
=−
=−
xLempung
xLanau
xPasir
GRUP INDEX
• GI = (F-35)[0,2+0,005(LL-40)] • + 0,01(F-15)(PI-10)• F = persentase butir lolos ayakan no 200• LL = batas cair ( Liquid Limit )• PI = index plastisitas
USDA
• PASIR 2 S/D 0,05 mm• LANAU 0,05 S/D 0,002 mm• LEMPUNG < 0,002 mm
CONTOH• USDA HANYA MENGKLASIFIKASI BUTIR LOLOS NO 10• JIKA ADA KANDUNGAN LEBIH BESAR , DIKOREKSI
• Tanah B dengan komposisi sbb :• 20 % kerikil, 10 % pasir, 30 % lanau 40 % lempung••• Pasir = ( 10 x 100 ) / ( 100 – 20 ) = 12,5 %• Lanau = ( 30 x 100 ) / ( 100 – 20 ) = 37,5 %• Lempung = ( 40 x 100 ) / ( 100 – 20 ) = 50,0 %
Atterberg Limits
• Analisa ukuran butir kurang cocok • Analisa ukuran butir kurang cocok untuk partikel lembut
Atterberg Limits
01020304050
Vo
lum
e
Hubungan antara Kadar Air vs Volume
0
0 50 100
Moisture Content (%)
LLSL PL
Atterberg Limits• Analisa saringan tidak bisa diterapkan
pada tanah berbutir lembut
1020304050
Vo
lum
e
Kadar air >< volume saat proses pengeringan SL -Shrinkage Limit
• PL - Plastic Limit• LL - Liquid limit
0
0 50 100
Moisture Content (%)
LLSL PL
Atterberg Limits
SL - Shrinkage LimitPL - Plastic LimitLL - Liquid limit
Moisture contentmassof water
=
Plasticity Index = LL - PL = PI or Ip
Moisture contentmassof water
massof solids=
BEBERAPA CONTOH KLASIFIKASI TANAH
STANDART AAHSO
• 1. Well graded sand or gravel: may include fines
• 2. Sands and Gravels with excess fines• 3. Fine sands• 4. Low compressibility silts• 5. High compressibility silts• 6. Low to medium compressibility clays• 7. High compressibility clays• 8. Peat and organic soils
Unified Soil Classification
• SETIAP JENIS TANAH DIBERI TANDA DUA • SETIAP JENIS TANAH DIBERI TANDA DUA HURUF, CONTOH SW ( PASIR GRADASI BAIK )
Unified Soil Classification• Jenis tanah ditandai dengan dua huruf (contoh. SW). • Prosedurnya sbb :
• Coarse grained (>50% lebih besar 75 µm)
• Huruf S jika > 50% butiran kasar adalah pasir• Huruf G jika > 50% butiran kasar adalah Gravel• Suffix tergantung prosentase kandungan butir halus• Jika % butir halus < 5% suffix nya W atau P• Jika % butir halus > 12% suffix nya M atau C• Jika 5% < % butir halus < 12% Memakai Dua simbol
Unified Soil ClassificationUntuk menentukan jenis W atau P, hitung Cu dan Cc
CD
Du = 60
10
CD
D Dc =×302
60 10( )
X % dari tanah berukuran lebih kecil dari Dx
Contoh ; D10 adalah berapa ukuran terbesar butiran , dimana prosentase terbesar butiran , dimana prosentase yang lolos saringan sebesar 10 %
Cu = Koefisien keseragaman
Cc = Koefisien gradasi
Unified Soil Classification
2 0
4 0
6 0
8 0
1 0 0%
Fin
er
0 .0 0 0 1 0 .0 0 1 0 .0 1 0 .1 1 1 0 1 0 00
2 0
P a r t i c l e s i z e ( m m )
D90 = 3 mm
Unified Soil Classification
CD
Du = 60
10
CD
D Dc =×302
60 10( )
If prefix is G then suffix is W if Cu > 4 and Cc is between 1 and 3 otherwise use P
If prefix is S then suffix is W if Cu > 6 and Cc is between 1 and 3 otherwise use P
60 10
Unified Soil Classification
40
50
60in
dex
CH
"A" lin
e
Comparing soils at equal liquid limit
Toughness and dry strength increase
with increasing plasticity index
Coarse grained soilsTo determine M or C use plasticity chart
0 10 20 30 40 50 60 70 80 90 100Liquid limit
0
10
20
30
Pla
stic
ity
OH
or
MH
CLOL
MLor
CL
ML
Plasticity chartfor laboratory classification of fine grained soilsBelow A-line use suffix M - Silt
Above A-line use suffix C - Clay
Unified Soil Classification– Tanah berbutir halus (> 50% lebih kecil 75 µm)– Kedua huruf ditentukan dari plasticity chart
40
50
60nd
ex
CH
"A" lin
e
Comparing soils at equal liquid limit
Toughness and dry strength increase
with increasing plasticity index
0 10 20 30 40 50 60 70 80 90 100Liquid limit
0
10
20
30
Pla
stic
ityin CH
OH
or
MH
CLOL
MLor
CL
ML
Plasticity chartfor laboratory classification of fine grained soils
Give typical names: indicate ap-proximate percentages of sandand gravel: maximum size:angularity, surface condition,and hardness of the coarsegrains: local or geological nameand other pertinent descriptiveinformation and symbol inparentheses.
For undisturbed soils add infor-mation on stratification, degreeof compactness, cementation,moisture conditions and drain-age characteristics.
Example:
Well graded gravels, gravel-sand mixtures, little or nofinesPoorly graded gravels, gravel-sand mixtures, little or nofinesSilty gravels, poorlygraded gravel-sand-silt mixtures
Clayey gravels, poorly gradedgravel-sand-clay mixtures
Well graded sands, gravellysands, little or no fines
Poorly graded sands, gravellysands, little or no fines
Silty sands, poorly gradedsand-silt mixtures
Clayey sands, poorly gradedsand-clay mixtures
GW
GP
GM
GC
SW
SP
SM
SC
Wide range of grain size and substantialamounts of all intermediate particlesizesPredominantly one size or a range ofsizes with some intermediate sizesmissing
Non-plastic fines (for identificationprocedures see ML below)
Plastic fines (for identification pro-cedures see CL below)
Wide range in grain sizes and sub-stantial amounts of all intermediateparticle sizes
Predominantely one size or a range ofsizes with some intermediate sizes missing
Non-plastic fines (for identification pro-cedures, see ML below)
Plastic fines (for identification pro-cedures, see CL below)
Field identification procedures(Excluding particles larger than 75mm and basing fractionson
estimated weights)
Groupsymbols
1Typical names Information required for
describing soilsLaboratory classification
criteria
C = Greater than 4DD----60
10U
C = Between 1 and 3(D )
D x D----------------------30
10c
2
60
Not meeting all gradation requirements for GW
Atterberg limits below"A" line or PI less than 4
Atterberg limits above "A"line with PI greater than 7
Above "A" line withPI between 4 and 7are borderline casesrequiring use of dualsymbols
Not meeting all gradation requirements for SW
C = Greater than 6DD----60
10U
C = Between 1 and 3(D )
D x D----------------------30
10c
2
60
Atterberg limits below"A" line or PI less than 4
Atterberg limits above"A"
Above "A" line withPI between 4 and 7are borderline casesrequiring useof dualet
erm
ine
perc
enta
ge
sof
grav
elan
dsa
ndfr
omg
rain
size
curv
e
the
frac
tion
sa
sg
ive
nun
der
field
iden
tific
atio
n
epen
ding
onpe
rcen
tage
sof
fine
s(f
ract
ion
smal
ler
than
.075
mm
eve
size
)co
ars
egr
ain
ed
soils
are
clas
sifie
das
follo
ws
ssth
an5%
ore
than
12%
%to
12%
GW
,GP,
SW
,SP
GM
,GC
,SM
,SC
Bor
delin
eca
sere
quir
ing
use
ofd
uals
ymbo
ls
smal
lest
par
ticle
visi
ble
toth
ena
ked
eye
Coa
rse
grai
ned
soils
Mor
eth
anha
lfof
mat
eria
lis
larg
erth
an.0
75m
msi
eve
size
Sand
sM
ore
than
half
ofco
arse
frac
tion
issm
alle
rth
an2.
36m
m
Gra
vels
Mor
eth
anha
lfof
coar
sefr
actio
nis
larg
erth
an2.
36m
m
Sand
sw
ithfin
esap
prec
iabl
eou
ntof
fines
)
Cle
ansa
nds
(lit
tleor
nofin
es)
Gra
vels
wit
hfin
es(a
prec
iabl
eam
ount
offin
es)
Cle
angr
avel
s(l
ittle
orno
fines
)
Unified soil classification (including identification and description)
Silty sand, gravelly; about 20%hard angular gravel particles12.5mm maximum size; roundedand subangular sand grainscoarse to fine, about 15% non-plastic lines with low drystrength; well compacted andmoist in places; alluvial sand;sand-clay mixturescedures, see CL below)
ML
CL,CI
OL
MH
CH
OH
Pt
Dry strengthcrushing
character-istics
None toslight
Medium tohigh
Slight tomedium
Slight tomedium
High to veryhigh
Medium tohigh
Readily identified by colour, odourspongy feel and frequently by fibroustexture
Dilatency(reaction
to shaking)
Quick toslow
None to veryslow
Slow
Slow tonone
None
None to veryhigh
Toughness(consistencynear plastic
limit)
None
Medium
Slight
Slight tomedium
High
Slight tomedium
Inorganic silts and very fine sands,rock flour, silty or clayeyfine sands with slight plasticityInorganic clays of low to mediumplasticity, gravelly clays, sandyclays, silty clays, lean clays
Organic silts and organic silt-clays of low plasticity
inorganic silts, micaceous ordictomaceous fine sandy orsilty soils, elastic silts
Inorganic clays of highplasticity, fat clays
Organic clays of medium tohigh plasticity
Peat and other highly organic soils
Give typical name; indicate degreeand character of plasticity,amount and maximum size ofcoarse grains: colour in wet con-dition, odour if any, local orgeological name, and other pert-inent descriptive information, andsymbol in parentheses
For undisturbed soils add infor-mation on structure, stratif-ication, consistency and undis-turbed and remoulded states,moisture and drainage conditions
ExampleClayey silt, brown: slightly plastic:small percentage of fine sand:numerous vertical root holes: firmand dry in places; loess; (ML)
Atterberg limits above"A"line with PI greater than 7
requiring useof dualsymbolsD
e
Use
gra
insi
zecu
rve
inid
entif
yingt De
sie
Le
Mo
5%
The
.075
mm
siev
esi
zeis
abo
utth
e
Fin
egr
aine
dso
ils
Mor
eth
anha
lfof
mat
eria
lis
smal
ler
than
.075
mm
siev
esi
ze
Silt
san
dcl
ays
liqui
dlim
itgr
eate
rth
an50
Silt
san
dcl
ays
liqui
dlim
itle
ssth
an50
M f S (ap
amo
Identification procedure on fraction smaller than .425mmsieve size
Highly organic soils
moist in places; alluvial sand;(SM)
0 10 20 30 40 50 60 70 80 90 100Liquid limit
0
10
20
30
40
50
60
Pla
stic
ityin
dex
CH
OH
or
MHOL
MLor
CL
"A" lin
e
Comparing soils at equal liquid limit
Toughness and dry strength increase
with increasing plasticity index
Plasticity chartfor laboratory classification of fine grained soils
CI
CL-MLCL-ML
CONTOH
40
60
80
100%
Fin
er
0.0001 0.001 0.01 0.1 1 10 1000
20
Particle size (mm)
CONTOH
40
60
80
100%
Fin
er
0.0001 0.001 0.01 0.1 1 10 1000
20
Particle size (mm)
• %fines (% finer than 75 µm) = 11% - Dual symbols required
CONTOH
40
60
80
100%
Fin
er
0.0001 0.001 0.01 0.1 1 10 1000
20
Particle size (mm)
• %fines (% finer than 75 µm) = 11% - Dual symbols required
• D10 = 0.06 mm, D30 = 0.25 mm, D60 = 0.75 mm
CONTOH
40
60
80
100%
Fin
er
0.0001 0.001 0.01 0.1 1 10 1000
20
Particle size (mm)
Particle size fractions: Gravel 17%
Sand 73%
Silt and Clay 10%
CONTOH
30
40
50
60
stic
ityin
dex
CH
"A" lin
e
Comparing soils at equal liquid limit
Toughness and dry strength increase
with increasing plasticity index
0 10 20 30 40 50 60 70 80 90 100Liquid limit
0
10
20Plas
OH
or
MH
CLOL
MLor
CL
ML
Plasticity chartfor laboratory classification of fine grained soils
Fraksi kasar 80% berupa pasir, pakai huruf S
Cu = 12.5, Cc = 1.38
Suffix1 = W
Dari Atterberg Tests
LL = 32, PL = 26
Ip = 32 - 26 = 6Ip = 32 - 26 = 6
Dari Plasticity Chart titik terletak dibawah garis A
Suffix2 = M
Dipakai simbol ganda SW-SM
Untuk melengkapi, simbol harus diberi diskripsi