![Page 1: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/1.jpg)
![Page 2: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/2.jpg)
GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE
Prof. J. N. Mandal
Department of civil engineering, IIT Bombay, Powai , Mumbai 400076, India. Tel.022-25767328email: [email protected]
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 3: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/3.jpg)
Module - 3LECTURE- 10
Geosynthetic properties and test methods
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 4: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/4.jpg)
Introduction Properties of geosynthetics Physical properties Mechanical properties Hydraulic properties Endurance properties
Geosynthetic clay liners (GCLs) properties and test methods Tensile strength of Nano material Ultimate versus allowable geosynthetics properties
OUTLINE
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 5: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/5.jpg)
Geosynthetic properties and test methods
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 6: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/6.jpg)
When to test geosynthetics?
Firstly for any project the design engineers must check therequired specifications of geosynthetic materials. Withoutknowing proper specifications, it is very difficult to select thecorrect geosynthetic for any specific project.
It is needed to conduct tests on geosynthetics from anindependent laboratory.
Generally, test results are supplied from manufacturer datasheet. These data sheets provide minimum average roll values(MARV) for quality control of geosynthetics.
Considering environmental impact, geosynthetics should becollected from the project site and sent to geosyntheticlaboratory for testing of their different properties.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 7: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/7.jpg)
Main strong reasons for exploring this exciting newengineering construction material in civil engineering areas follows: Excellent stress-strain behavior Good flexibility Excellent filtration characteristics High water permeability Excellent mechanical properties Can be welded together Does not form by-products High resistance to climate condition High resistance to chemical and biological attack Chemically ultraviolet stabilized Time, cost, rapid construction, environment friendly,
sustainability and durabilityProf. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 8: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/8.jpg)
Tests on geosynthetics are conducted in two different ways:
A) Index tests or in-isolation tests: Tests are performed only on geosynthetics itself
B) Performance tests: Tests are performed along with site-specific soil.
Physical Properties
Mechanical Properties
Hydraulic Properties
Endurance Properties
PROPERTIES OF GEOSYNTHETICS
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 9: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/9.jpg)
Mass per unit area (Weight)
Thickness
Specific gravity
Stiffness or flexural rigidity or flexural stiffness
Physical Properties
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 10: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/10.jpg)
Mass per unit area (ASTM D5261) Five test specimens are to be weighed in a weighingmachine (accuracy of 0.01 g) and average value is recorded. Test samples are of size 100 mm 100 mm Unit is expressed as g/m2
The cost of geotextile is directly related to the weight ofgeotextile.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 11: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/11.jpg)
Thickness (ASTM D5199)
Geotextiles exhibit different thickness according todifferent pressures.
The thickness is measured to an accuracy of 0.02 mmunder a specified pressure of 2.0 kPa.
Sample size is 200 mm 200 mm. The thickness isgenerally in the range of 0.25 to 8.5 mm.
The thickness of geogrids and geomembranes aremeasured under a normal stress of 20 kPa.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 12: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/12.jpg)
Thickness measurement of geotextile
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 13: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/13.jpg)
Materials Sp. Gravity
Polypropylene (PP) 0.91
Polyethylene (PE) 0.9 to 0.96
Polyester (PET) 1.22 to 1.38
Polyvinyl chloride (PVC) 1.69
Nylon 1.05 to 1.14
Specific gravity (ASTM D 792 or D1505)
Specific gravity can be defined as ratio of the unit weight ofmaterial to the unit weight of distilled water at 4°C.
Specific gravity of different geosynthetic materials
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 14: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/14.jpg)
The geotextile specimen is a 25 mm wide strip.
The geotextile is placed along the length of a horizontalplane and bends gravitationally under its own weight on ainclined plane making an angle of 41.5 degree with thehorizontal.
Stiffness or flexural rigidity or flexural stiffness (ASTM D1388)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 15: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/15.jpg)
Stiffness of the geotextile = (l/2)3 x W
l = length of overhang geotextile and bending length = l/2(cm), w = mass per unit area (mg/cm2)
The unit of stiffness is mg-cm.
The minimum stiffness of geotextile depends on the variousdegree of required workability (Haliburton et al., 1980)
The property is important in field workability requirementsfor installation of geotextile.
If the soil is very poor or California bearing ratio value isvery less, the stiffness of geotextile required is very high.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 16: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/16.jpg)
Mechanical Properties
Compressibility Tensile strength test of geosynthetics Burst strength test Puncture Resistance Test Penetration resistance test (drop test)/ drop cone
(impact strength)/ tear (impact) resistance Tensile behavior of geogrid Tensile strength of Gabions Direct shear test Pullout or anchorage resistance Tensile strength of geomembrane Tear resistance of Geomembrane
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 17: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/17.jpg)
Compressibility Compressibility indicates the reduction in thickness underapplied pressure. Compressibility of geotextile depends on itsthickness and mass per unit area.
As the pressure increases, thickness of non-woven needle-punched (NW-NP) and resin bonded geotextiles gets reducedsignificantly and accordingly, the transmissivity gets reduced.
Compressibility of woven and non-woven heat bondedgeotextile (NW-HB) is low.
Compressibility of nonwoven needle-punched geotextileplays a very important role as most of the time we use thesetype of geotextiles to pass the liquid along their plane.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 18: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/18.jpg)
Variation in thickness of geosynthetics with change in pressure
It is clearly observed that nonwoven needle punchedgeosynthetics are more compressible.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 19: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/19.jpg)
Tensile strength
Wide width tensile strength
(ASTM D4595 and ISO 10319)
Very wide width tensile strength test
Narrow strip tensile strength (ASTM D4751)
Sewn seam strength of geotextile
(ASTM D4884 and ISO 13426)
Grab tensile strength (ASTM D4632)
Trapezoidal tear strength test
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 20: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/20.jpg)
Wide width tensile strength (ASTM D4595)
Nonwoven geotextiles Woven jute geotextiles
Test result on a thermally bonded nonwoven geotextileProf. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 21: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/21.jpg)
The machine strain rate is 10 ± 3 %.
The reason for the necessity of wide-width specimens isthat geotextiles (particularly non-woven) achieve highpoison’s ratio value from narrow strip test.
Tensile strength of geotextile (Tgeotextile) can be expressedas force per unit width.
Tgeotextile = Fb/ W (kN/m)
Fb = Observed breaking force (kN), and
W = Specimen width (meter)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 22: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/22.jpg)
Very wide width tensile strength test
Size of sample for very wide width test
For design purpose, the very wide width tensile test is notrecommended.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 23: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/23.jpg)
Narrow strip tensile strength (ASTM D 1682)
Strain rate = 300 mm/ min
Tensile strength appearslow compared to wide widthtensile strength test.
Not recommended asdesign value.
Size of test sample with the test assembly
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 24: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/24.jpg)
Tensile modulus:
Different tensile modulus from typical stress-strain curves
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 25: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/25.jpg)
Tensile strength vs. strain curves for different geotextiles
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 26: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/26.jpg)
Case 1:
For Sample - 1, Maximum tensile stress, Tmax = 30 kN/m Maximum strain = εg =45% Initial tangent modulus (E) = Initial slope of the curve
= 12/0.08 = 150 kN/m Toughness, TU = ½ × Tmax × εg = 1/2 × 30 × 0.45 = 6.75 kN/m
Case 2:
For sample - 2, Initial tangent modulus (E) = 8/ 0.50 = 16 kN/m Offset modulus = 20/ (0.31-0.20) = 181.8 kN/m Secant modulus at 40% strain, E40 = 34/ 0.40 = 85 kN/m
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 27: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/27.jpg)
Sewn seam strength of geotextile (ASTM D4884 and ISO 13426)
(After Diaz, 1985)
Size of test sample for sewn seam strength
Strain rate =10 ± 3 %/ min, Unit in kN/mButterfly seam is recommended for sewing
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 28: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/28.jpg)
The seam strength efficiency can be expressed as,
SE = (Tseam / Tg) x100 %
Where,
Tseam = wide width seam strength (ASTM D 4884), and
Tg = wide width geosynthetic strength without seam(ASTM D 4595)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 29: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/29.jpg)
Grab Tensile Test (ASTM D 1682)
The test relies on filament interaction in geotextile. Fornonwoven geotextile, the effects are more than wovengeotextile. The grab tensile test is reported in kN, not in kN/m.
As the sample is partially clamped, stress is not propagatedin entire width of the sample. It is an unusual test and widelymisused.
Grab tensile test specimen Laboratory Grab tensile test
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 30: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/30.jpg)
Analytical analysis of grab tensile strength:
Grab tensile strength is required to design the geotextilesfor separation. When pressure is applied to the upperstone, it spreads the two lower stones laterally. As a result,tension is mobilized in the geotextile. It is analogous to thegrab tensile strength test.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 31: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/31.jpg)
222DDD
22 DD
D = Diameter of stoneli= Initial length of geotextile =
lf = final length of geotextile =
Without any stone breakage or slippage, maximum strain in geotextile can be expressed as,
%3331
23
22222
100
D
DDDDD
lll
i
if
Treqd = Ap (Dv)2 ε (Giroud,1984)
Treqd = required grab strength, Ap = applied pressure,Dv = maximum void diameter = 0.33Da, Da = average stone diameter
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 32: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/32.jpg)
Example:
Tire inflation pressure = 650 kPa. Average stone diameter =50 mm. Assume the geotextile is placed beneath stone basecourse. Calculate required grab tensile strength of thegeotextile. Assume 50 % of total ultimate grab strain willmobilize.
Solution:We know that total ultimate grab strain = 33%.
So, the mobilized grab strain = 0.33 x 0.5 = 0.165
Hence, Treqd = 650 × (0.33 × 0.05)2 × 0.165 = 29.2 Newton
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 33: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/33.jpg)
Trapezoidal tear strength test (ASTM D4533 and ISO 13434)
This test is done to tear the test specimen from the point ofincision.
Tear strength is important when the geosynthetic isdamaged.
Trapezoidal tear strengthis measured in N.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 34: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/34.jpg)
Burst strength test
Different types of burst strength test apparatus
Unit in kN/m2
(a) Mullen burst (ASTM D 3786)
(b) Ball burst (ASTM D 751)
(c) CBR burst (DIN 54307 E)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 35: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/35.jpg)
Analytical analysis of burst strength test:Burst strength is required to design the geotextiles forseparation. The geotextile may burst due to the appliedupward load.
Field model for burst resistance (Geotextile being forced up into voids of stone base due to traffic tire loads)
Laboratory simulation
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 36: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/36.jpg)
gvgreqd DP21T
v
v
v
vg z2
wwz2
41
Theoretically, from the field concept Giroud (1984) developed a formula for required geotextile burst strength (Treqd).
Strain in geotextile (εg) depends on width of void (wv) anddeformation of the void (zv).
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 37: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/37.jpg)
Mullen burst test can be analogous to the field conditions,
Experimental model set up forburst strength in laboratory
Geotextile is pushed upward and it forms hemispherical shapeas well as fails due to radial tension. So, the ultimate strength(Tult) of geotextile can be written as,
gbbult DP21T
Pb = Burst strength, Db = Diameter of burst equipment ≈ 30 mm, εg = Strain in geotextile
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 38: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/38.jpg)
(C.R.F)factor reduction CumulativeTT ult
allowable
vg
bb
reqd
allow
DP.)F.R.C(DP
TT.S.F
If Dv = 0.33 Da, Db = 30 mm, C.R.F. = 1.5
ag
b
ag
b
DPP6.60
)D33.0(P)5.1(30P.S.F
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 39: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/39.jpg)
Design chart for burst analysis of geotextile considering reduction factor = 1.5 and factor of safety = 2.0
The design chart reveals that size of stone aggregatepossess a significant impact on the burst strength of geotextile.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 40: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/40.jpg)
Example :
Let, tire inflation pressure (Pt) = Pg = 650 kPa and maximumsize of stone = 60 mm. Determine the required burststrength of geotextile using C.R.F = 1.5 and F.S. = 2.0.
ag
b
DPP6.60FS
kPa12876.60
6065026.60DPS.F
P agb
Solution:
We know, for C.R.F. = 1.5,
So, the required burst resistance is 1287 kPa.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 41: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/41.jpg)
Please let us hear from you
Any question?
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
![Page 42: GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE...Thickness (ASTM D5199) Geotextiles exhibit different thickness according to different pressures. The thickness is measured to an](https://reader035.vdocument.in/reader035/viewer/2022070213/610b07013e4c45556a417ac8/html5/thumbnails/42.jpg)
Prof. J. N. Mandal
Department of civil engineering, IIT Bombay, Powai , Mumbai 400076, India. Tel.022-25767328email: [email protected]
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay