effect of particle-size gradation on coarse sand-geotextile … · 2020. 9. 3. · test. among the...

Research ArticleEffect of Particle-Size Gradation on Coarse Sand-GeotextileInterface Response in Cyclic and Postcyclic Direct Shear Test

Jun Wang1 Meng-Jie Ying2 Fei-Yu Liu 3 Hong-Tao Fu4 Jun-Feng Ni4 and Jing Shi2

1Architecture and Civil Engineering College Wenzhou University Wenzhou 325025 Zhejiang China2Department of Civil Engineering Shanghai University Shanghai 200444 China3College of Architecture and Civil Engineering East China Jiaotong University Nanchang 330013 China4Department of Civil Engineering and Architecture Saga University Saga 840-8502 Japan

Correspondence should be addressed to Fei-Yu Liu lfyzjushueducn

Received 28 February 2019 Revised 12 June 2019 Accepted 22 May 2020 Published 3 September 2020

Academic Editor Castorina S Vieira

Copyright copy 2020 Jun Wang et al is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In order to investigate the influence of sand particle-size gradation on cyclic and postcyclic shear strength behaviour on sand-geotextile interfaces a series of monotonic direct shear (MDS) cyclic direct shear (CDS) and postcyclic direct shear (PCDS) testswere performed using a large-scale direct shear apparatuse influence of cyclic shear history on the direct shear behaviour of theinterface was studied e results indicated that cyclic shear stress degradation occurred at the sand-geotextile interface Shearvolumetric contraction induced by the cyclic direct shear increased with the increase in cycle numbere lowest final contractionvalue was observed in discontinuously graded sand In the MDS tests there were great differences in interface shear strength dueto the different particle-size gradations whereas the differences between shear volumes were negligible In the PCDS tests theshear stress-displacement curves exhibited postpeak stress hardening behaviour for different particle-size gradations and dif-ferences in shear volumes were detected e well-graded sand-geotextile interface had a higher value of shear stiffness and ahigher damping ratio relative to the other interfaces Postcyclic shear stress degradation was observed for the discontinuouslygraded sand-geotextile interface

1 Introduction

Soil reinforcement techniques were firstly put forward byVidal [1] and have been widely applied in geotechnicalengineering e geotextile-reinforced soil structures in-cluding reinforced retaining wall slope and embankmentplay a vital role in the construction of infrastructure such ashighway railway port and airport Recently differentlaboratory experimental research studies and numericalsimulations have been conducted on these structures [2ndash5]

Wang et al [6 7] revealed that soil-geotextile interactionplays a significant contribution in the stability and bearingcapacity of earth structures e ability of geotextile en-hances the performance of retaining walls and embankmentin terms of reducing the surface deformation Further theinteraction mechanism between soil and geosynthetic needsto have a clear understanding and more accurate

determination So various experimental studies have beenmade to investigate the interface mechanism by direct sheartests pull-out tests inclined plane tests and torsional ringshear tests [8ndash11] Among these testing methods the directshear method is one of the most commonly used methods indetermining the frictional behaviour of geosynthetic-soilinterface

A series of factors may have significant impacts on thestatic shear behaviour of soil-geosynthetic interface Afzali-Nejad et al [12] investigated the influence of particle shapeon shear strength and dilation of sand-woven geotextileinterfaces Infante et al [13] showed that the interface shearstrength was significantly affected by the factors of type ofgeosynthetics and density of soils Ferreira et al [14] ex-amined the influences of soil moisture content and geo-synthetic type on the soil-geosynthetic interface Anubhavand Basudhar [15] concluded that the particle shape was an

HindawiAdvances in Civil EngineeringVolume 2020 Article ID 1323296 11 pageshttpsdoiorg10115520201323296

important parameter to study the interface behaviour It wasfound that the frictional behaviour of reinforced soil in-terface was mainly influenced by the properties of soil andproperties of reinforcement

Cyclic direct shear tests are performed to characterizethe interaction near the base of the slope between twomaterials in reinforced soil structures under traffic seismicand other types of cyclic loading Liu et al and Wang et al[2 16] discussed the effect of soil particle size on the cyclicand postcyclic shear behaviour between sand and geogridinterface Alaie and Chenari [17] conducted the monotoniccyclic and postcyclic tests in EPS-sand-geogrid mixturesUnder cyclic direct shear tests there is also a need to un-derstand the interlocking on sand-geotextile interface eeffect of particle-size gradation on cyclic shear strength hasnot been fully studied Furthermore the comparison be-tween monotonic direct shear tests and postcyclic directshear behaviour under the effect of particle-size gradation oncyclic shear tests requires further discussion andinvestigation

e primary objective of this study is to investigate theeffect of sand particle-size gradation on shear behaviours ofthe sand-geotextile interface via laboratory large-scale directshear test e sand used in the tests was classified based onthe grain diameter Both monotonic direct shear (MDS) andcyclic direct shear (CDS) tests were performed under dif-ferent normal stresses e interface shear properties in-cluding shear stiffness damping ratios and shear strengthenvelope were specifically examined in detail

2 Materials and Methods

21 Testing Apparatus e direct shear testing device usedin this study is the ShearTrac-III Large-Scale Direct ShearApparatus designed and constructed by Geocomp edevice consists of an upper box with dimensions of305mmtimes 305mm in length and width and 100mm inheight and a lower box of 305mmtimes 405mm in length andwidth and 100mm in height e maximum horizontaldisplacement is 100mm e lower box is larger than theupper box which ensures a constant contact areathroughout the shearing process e device can apply staticshear as well as cyclic shear and these effects can be eitherload-controlled or displacement-controlled For this studydisplacement-controlled tests were performed e upperbox is fixed in the horizontal direction whereas the lowerbox moves horizontally driven by high-accuracy electricmotors e maximum shearing rate is 15mmmin eloading system shows good control of the normal stressduring testing and even significant volumetric contractionis recorded by a liner variable differential transformer(LVDT) respectively

22 Test Materials e test materialwasselected as thecoarse silica sand with a specific gravity (Gs) of 265 iscoarse sand was divided into four classes by screening forgrain size e particle sizes (diameter) of the four classeswereS1 (05ndash1 mm) S2 (1ndash2 mm) S3 (2ndash4mm) and S4

(4ndash8 mm) According to the Unified Soil ClassificationSystem (USCS) these four classes of coarse sand weremixed in predetermined proportions and classified aswell-graded coarse sand (C1) poorly graded coarse sand(C2) and discontinuously graded coarse sand (C3) ecoefficient of uniformity (Cu) of three samples were 571323 and 172 and the coefficient of curvature (Cc) were143 081 and 087 e particle-size distribution curvesof the sands are presented in Figure 1 e woven geo-textile was used in this paper e properties of thegeotextile are listed in Table 1

23 Testing Procedures A series of CDS MDS and PCDStests were conducted to evaluate shear behaviours of thecoarse sand-geotextile interfaces According to ASTMD5321 [18] the shearing displacement rate was desig-nated as 1 mmmin of 30 60 and 90 kPa for all tests theshear displacement amplitude for the CDS tests wasdesignated as 3 mm and the number of cycles wasdesignated as 10 e top surface of the sand was kept ashorizontal as possible until the specified elevation wasreached at which time the total mass of sand loaded wasrecorded During each test a rigid block was placed in thelower box e geotextilewas fixed over the lower boxwith bolts and steel blocks to ensure that there was norelative displacement between the material and the lowerbox e shear occurred along the sand-geotextile in-terface e validity of the method of placing rigid blocksin the lower box has been demonstrated in [19] ecyclic shear path is shown in Figure 2(a) e lower shearbox moved from the equilibrium position following theshear path ①-②-③-④ which was defined as oneloading cycle After the CDS test was completed thenormal stress applied to the sample was unloaded andreloaded to the target value of the PCDS test e MDStests without cyclic shearing were performed on thereloaded specimens

01 1 100

10

20

30

40

50

60

70

80

90

100

Perc

ent f

iner

Particle size (mm)

C1C2C3

Figure 1 Particle-size distribution curves for the test sands

2 Advances in Civil Engineering

3 Cyclic Direct Shear Test Results

e shear stress versus shear displacement curves for theresults of the CDS tests with the three interfaces undernormal stress of 90 kPa are shown in Figure 3e peak shearstress in the hysteresis loops decreases with increasingnumber of cycles and the sand-geotextile interfaceshear strength tends to show cyclic shear softening for allthree particle-size gradations is phenomenon is mainlycaused by interface wear and deformation which changesthe mechanical properties of the geotextile under cyclicshearing [20] In each shear cycle the peak shear stress in theinitial direction is higher than that in the opposite directione variation may be related to the anisotropic sand positioncaused by initial shear e stress-displacement hysteresisloops present a tendency toward stabilization at the end oftest Among the sand-geotextile interfaces results the C1-geotextile interface has the greatest shear stress and C3-geotextile interface has the least e maximum peak shearstress of C1-geotextile C2-geotextile and C3-geotextile are3167 3083 and 2833 kPa It shows that fine particle-sizegradation has an important effect on interparticle lockingand shear strengthis observation is consistent withWanget al [21]

e interface vertical displacement versus shear dis-placement curves from the CDS test results for the threeinterfaces are shown in Figure 4 For all three particle-sizegradations vertical contraction is observed over theentire shearing process During the shearing process thechange in vertical displacement is observed as volumechange of the contact surface In this study compression

of volume deformation of the contact surface is negativeand expansion is positive e sand volume decreasesthroughout the entire process of cyclic shear In initialcycle number C2-geotextile interface contraction in-creases more rapidly than other sand-geotextile inter-faces e variation of vertical displacement withincreasing cycle number for the three interfaces is shownin Figure 5 e interface vertical displacement generallyincreases with increasing number of cycles However thevolumetric contraction of sand develops quickly at initialcycle number and the increment gradually decreaseswith the increasing number of cycles for the three kinds ofsand-geotextile interfaces e curves between adjacentstress loops become closer to each other is phenom-enon is also observed by Liu et al and Wang et al [2 16]Of the three particle-size gradations vertical displace-ment is minimum for discontinuously graded coarse C3-geotextile interface e C2-geotextile interface has thelargest vertical displacement owing to the larger voidratio of sand In the case of the well-graded sands thesmaller particles facilitate rolling and sliding of the largerparticles changing the kinematics of the shearingprocess

4 Influence of Cyclic ShearHistory on InterfaceShear Behaviour

Figure 6 shows the shear stress versus shear displacementcurves obtained in the MDS and PCDS tests for the threeinterfaces under normal stress of 90 kPa e tendency ofthe shear stress versus shear displacement curves is

Table 1 Main characteristics of the geotextile

Geotextile Mass per unit area (gm2)

Trapezoidaltearing strength

(kNm)

Elongation atbreak ()

Ultimate tensilestrength (kNm)

TD LD TD LD TD LDWoven geotextile 150 04 04 28 28 20 28TD transverse direction LD longitudinal direction

4Shear displacement

Block

Upper box

405mm

100mm

100mmLower box

305mm

Equilibrium position(shear displacement = 0)

1

23

0

Geotextile

(a)

Time

3T4T4 T2 T0

Shear displacement amplitude (Aw)

(b)

Figure 2 Schematic of the cyclic shear paths (a) e cyclic shear path (b) Waveform of cyclic load

Advances in Civil Engineering 3

similar for the three coarse-grained sand-geotextile in-terfaces No peak values are apparent and all of thesecurves show shear hardening behaviour In addition inboth the MDS tests and PCDS tests the C1-geotextileinterface has the greatest shear strength and the C3-geotextile interface has the least It indicates that well-graded coarse sand has large interlocking of C1-geotextileinterface After the samples undergoing cyclic direct sheartests the increment in interface shear strength is evidentespecially for the C1-geotextile interface

Figure 7 shows the interface vertical displacementversus shear displacement curves obtained from the MDSand PCDS tests for the three interfaces under normalstress of 90 kPa Similar contraction tendency occursduring the entire process of volume development for allthree interfaces Particle-size gradation has greater in-fluence on interface deformation in the PCDS testscompared with the CDS tests e vertical displacementin the MDS tests is larger than that in the PCDS tests Amain factor for this phenomenon is that the interfacedensification is accelerated during the cyclic shearinge influence of coarse-grained sand particle gradation

on the interfacial deformation in the PCDS tests isgreater than that in the MDS tests is observation canbe attributed to the difference of content of particle sizeComparing the vertical displacement of MDS with PCDStests the vertical displacement of C1-geotextile and C2-geotextile interface shows large difference is resultsindicate that discontinuously graded coarse sand hasmore content of smaller particle size which makes itmore easily for rearrangement and crushing of particles[22]

Figure 8 shows the interface shear stress versus sheardisplacement curves obtained from the CDS and PCDStests for the three interfaces under normal stresses of30 kPa and 90 kPa In the PCDS tests the shear strength ofthe C1-geotextile interface and the C2-geotextile interfaceincreases whereas the shear strength of the C3-geotextileinterface decreases is phenomenon is more apparentunder the lower normal stress Under both levels ofnormal stress C1-geotextile interface presents the greatestshear strength whereas C3-geotextile interface presentsthe least shear strength ese results indicate that thewell-graded coarse-grained sand has higher shear strength

C1-geotextile

ndash2 ndash1 0 1 2 3ndash3Shear displacement (mm)

ndash40

ndash20

0

20

40Sh

ear s

tres

s (kP

a)

(a)

C2-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(b)

C3-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(c)

Figure 3 Effect of sand particle-size gradation on the interface shear stress-shear displacement curves in the CDS tests


C1-geotextile

ndash08

ndash06

ndash04

ndash02

00V

ertic

al d

ispla

cem

ent (

mm

)


(a)

C2-geotextile

ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(b)

C3-geotextile

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(c)

Figure 4 Effect of sand particle-size gradation on the interface vertical displacement-shear displacement curves in the CDS tests

ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)

C1-geotextileC2-geotextileC3-geotextile

2 4 6 8 100Cycle number N

Figure 5 Relationships between interface vertical displacement and number of cycles with different sand particle-size gradations


and that sand particle-size gradation affects the shearstrength of interfaces in MDS and PCDS tests

Comparison of the vertical displacement versus shear dis-placement curves from the MDS and PCDS tests for the threeinterfaces under normal stresses of 30kPa and 90kPa is shownin Figure 9e vertical displacement versus shear displacementcurves for the three interfaces present greater differences and thecurve inflections change after the samples undergoning cyclicdirect shear Compared with the MDS tests the PCDS testsresult in more severe dilatation of the interfaces is phe-nomenon can be attributed to the findings that densification ofthe interface is accelerated by cyclic direct shear e rear-rangement behaviour of sand particles consists mainly ofscrolling and climbing which mainly leads to more dilatation[23] Under the normal stress of 30kPa the geotextile-reinforced

sand undergoes vertical contraction during the initial stage andthen exhibit dilatancy whereas vertical contraction is observedthroughout the entire course of shearing under the normal stressof 90kPa From comparison of Figure 8 with Figure 9 it isevident that the reinforced sand interfaces exhibit dilatancyassociated with a corresponding decrease in shear stress underthe normal stress of 30kPa In contrast higher shear strength isobserved for all three interfaces under the normal stress of90kPa

5 Discussion

51 Shear Stiffness andDampingRatios Under cyclic loadingof earthquakes and waves the secant shear modulus anddamping ratio of soil are two indispensable dynamic

0

10

20

30

40

50

60

70Sh

ear s

tres

s (kP

a)


5 10 15 20 25 30 350Shear displacement (mm)

(a)


0

10

20

30

40

50

60

70

Shea

r str

ess (

kPa)


(b)

Figure 6 Effect of sand particle size on the interface shear stress-shear displacement curves in the (a) MDS and (b) PCDS tests


ndash05

ndash04

ndash03

ndash02

ndash01

00

Ver

tical

disp

lace

men

t (m

m)


(a)

ndash020

ndash015

ndash010

ndash005

000

Ver

tical

disp

lace

men

t (m

m)



(b)

Figure 7 Effect of sand particle size on the interface vertical displacement-shear displacement curves in the (a) MDS and (b) PCDS tests


parameters as typically used in equivalent linear groundmotion analysis [24 25] Based on the definitions of shearstiffness and the damping ratio and the asymmetry of thesame hysteresis loop in two shear directions the shearstiffness (K) from a hysteresis loop are calculated according tothe following formula

K τmax + τmin

2Δa (1)

where τmax and τmin are the maximum shear stress and theminimum shear stress for two shearing directions and Δa isthe displacement semiamplitude e damping ratio (D) isdefined as

D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857

KΔWπ τ2max + τ2min( 1113857

(2)

where ΔW is the total area enclosed by the loop Figure 10depicts the parameter definitions of shear stiffness and thedamping ratio from the hysteresis loop

Figure 11 shows the variations of the shear stiffnessand damping ratio with increasing number of cycles forthe three interfaces under normal stress of 90 kPa edevelopment of shear stiffness follows a similar patternfor all three interfaces In the initial stage interface shearstiffness decreases rapidly and then the value of shearstiffness gradually tends to be stable at the end of cycleis indicates that the interface responds to shearsoftening However the values of shear stiffness varybetween the three interfaces for the same cycle numberOverall the shear stiffness values for the C1-geotextile andC2-geotextile interfaces are higher than those for the C3-geotextile interface It shows that well-graded sand in C1-geotextile has stronger resistance to sand deformationDiscontinuously graded coarse sand with weak internalcontact force in C3-geotextile interface leads to lower shearresistance As shown in Figure 11(b) there is a consistentpattern in the development of the damping ratios of all threeinterfaces e damping ratio of each interface decreasesrapidly with increasing number of cycles during the initialstage and then generally increases is trend indicates that

0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile


MDS (30kPa)MDS (90kPa)

PCDS (30kPa)PCDS (90kPa)

(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)

Figure 8 Comparison of the shear stress-shear displacement curves for the MDS and PCDS tests


the number of cycles affects the security and stability of theinterface subjected to cyclic shear In addition the dampingratio of the well-graded sand-geotextile interface is largerthan that of the other interfaces for the same cycle numbere results indicate that energy dissipates more slowly at awell-graded sand-geotextile interface subjected to cyclicshear

52 Shear Strength Envelope Curve Figure 12 shows theresults of linear fitting between the shear strength of thethree coarse sand-geotextile interfaces and the normal stressof these interfaces in the MDS and PCDS tests ese resultsindicate that in the range of vertical stress evaluated in thisstudy there is a strong linear relationship between interfaceshear strength and vertical stress erefore the

C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)

Figure 9 Comparison of the shear displacement-vertical displacement curves for the MDS and PCDS tests

K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W

Figure 10 Calculation of the secant shear stiffness and damping ratio from a hysteresis loop


MohrndashCoulomb criterion can be applied to express interfaceshear strength τ c + σ tanϕ where c is the interface ap-parent adhesion ϕ is the interface friction angle and R2 isthe correlation parameter of the envelope curves In theMDS tests for the C1-geotextile C2-geotextile and C3-geotextile interfaces the apparent adhesion (c) are 835 769and 1814 kPa respectively and the friction angles (ϕ) are301deg 288deg and 216deg respectively It indicates that well-graded sand leads to an increase in the interface apparent

adhesion and friction angle In the PCDS tests for the C1-geotextile interface the apparent adhesion c increases from835 kPa to 135 kPa which is 617 higher than that in theMDS tests and the friction angle ϕ is 291deg For the C2-geotextile interface the apparent adhesion c increases from769 kPa to 1474 kPa which is 917 higher than that in theMDS tests and the friction angle ϕ decreases to 247deg For theC3-geotextile interface the apparent adhesion c is 1679 kPaand the friction angle ϕ is 218deg From the results of PCDS

8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)

0 2 4 6 8 10Cycle number N


(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)

Figure 11 (a) Development of shear stiffness with cycle number and (b) development of damping ratio with cycle number

30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)

Vertical stress (kPa)

τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)

40 50 60 70 80 9030Vertical stress (kPa)


(b)

Figure 12 Shear strength envelopes for the (a) MDS and (b) PCDS tests


test the apparent adhesion of the interface increases but thefriction angle of the interface decreases

6 Conclusionse effect of particle-size gradation on shear strength anddeformation of sand-geotextile interface was studied Shearstrength softening and shear contraction were observed incyclic shearing for all three of the sand-geotextile interfacese interface with well-graded coarse sands had greatershear strength than the others e interface with discon-tinuously graded coarse sands had the smallest value ofcontraction

In the MDS and PCDS tests shear hardening was ob-served at the sand-geotextile interfaces Under lower normalstress the geotextile-reinforced sands underwent verticalcontraction during the initial stage and then exhibited di-latancy whereas vertical contraction was observedthroughout the entire shearing process under higher normalstress

For all three sand particle-size distributions the interfaceshear stiffness decreased with increasing number of cyclese damping ratio decreased with increasing number ofcycles during the initial shear cycles and then generallyincreased Of the three interfaces at the same number ofcycles the one with well-graded coarse sands had thegreatest shear stiffness and damping ratio

e shear strength and apparent adhesion of the in-terfaces with well-graded and poorly graded coarse sandsincreased after cyclic direct shear was applied whereas theinterface with discontinuously graded coarse sands exhibitedopposite tendencies

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors declare that they have no conflicts of interestregarding the publication of this paper

Acknowledgments

is study was supported by the National Key RampD Programof China (grant no 2016YFC0800200) the National NaturalScience Foundation of China (grant nos 5167835251622810 51978534 and 51878402) the Zhejiang ProvinceNatural Foundation Projects of China (grant noLR18E080001) and the Key Research and DevelopmentProgram of Zhejiang Province (grant no 2018C03038)

References

[1] H Vidal4e Principal of Reinforced Earth Highway ResearchRecord Washington DC USA 1969

[2] F-Y Liu P Wang X Geng J Wang and X Lin ldquoCyclic andpost-cyclic behaviour from sand-geogrid interface large-scaledirect shear testsrdquo Geosynthetics International vol 23 no 2pp 129ndash139 2016

[3] G Gao and M A Meguid ldquoEffect of particle shape on theresponse of geogrid-reinforced systems insights from 3Ddiscrete element analysisrdquo Geotextiles and Geomembranesvol 46 no 6 pp 685ndash698 2018

[4] E Guler M Hamderi and M M Demirkan ldquoNumericalanalysis of reinforced soil-retaining wall structures with co-hesive and granular backfillsrdquo Geosynthetics Internationalvol 14 no 6 pp 330ndash345 2007

[5] M Abdesssemed S Kenai and A Bali ldquoExperimental andnumerical analysis of the behavior of an airport pavementreinforced by geogridsrdquo Construction and Building Materialsvol 94 pp 547ndash554 2015

[6] Z Wang F Jacobs and M Ziegler ldquoVisualization of loadtransfer behaviour between geogrid and sand using PFC2DrdquoGeotextiles and Geomembranes vol 42 no 2 pp 83ndash90 2014

[7] Z Wang F Jacobs and M Ziegler ldquoExperimental and DEMinvestigation of geogrid-soil interaction under pullout loadsrdquoGeotextiles and Geomembranes vol 44 no 3 pp 230ndash2462016

[8] R A Jewell and C P Wroth ldquoDirect shear tests on reinforcedsandrdquo Geotechnique vol 37 no 1 pp 53ndash68 1987

[9] S A Tan S H Chew and W K Wong ldquoSand-geotextileinterface shear strength by torsional ring shear testsrdquo Geo-textiles and Geomembranes vol 16 no 3 pp 161ndash174 1998

[10] L Carbone J P Gourc P Carrubba P Pavanello andN Moraci ldquoDry friction behaviour of a geosynthetic interfaceusing inclined plane and shaking table testsrdquo Geotextiles andGeomembranes vol 43 no 4 pp 293ndash306 2015

[11] A Mirzaalimohammadi M Ghazavi M Roustaei andS H Lajevardi ldquoPullout response of strengthened geo-synthetic interacting with fine sandrdquo Geotextiles and Geo-membranes vol 47 no 4 pp 530ndash541 2019

[12] A Afzali-Nejad A Lashkari and P T Shourijeh ldquoInfluenceof particle shape on the shear strength and dilation of sand-woven geotextile interfacesrdquo Geotextiles and Geomembranesvol 45 no 1 pp 54ndash66 2017

[13] D J U Infante G M A Martinez P A Arrua andM Eberhardt ldquoShear strength behavior of different geo-synthetic reinforced sand structure from direct shear testrdquoInternational Journal of Geosynthetics and Ground Engi-neering vol 2 no 2 pp 1ndash16 2016

[14] F B Ferreira C S Vieira and M L Lopes ldquoDirect shearbehaviour of residual soil-geosynthetic interfaces-influence ofsoil moisture content soil density and geosynthetic typerdquoGeosynthetics International vol 22 no 3 pp 257ndash272 2015

[15] Anubhav and P K Basudhar ldquoInterface behavior of wovengeotextile with rounded and angular particle sandrdquo Journal ofMaterials In Civil Engineering vol 25 no 12 pp 1970ndash19742013

[16] JWang F Y Liu PWang and Y Q Cai ldquoParticle size effectson coarse soil-geogrid interface response in cyclic and post-cyclic direct shear testsrdquo Geotextiles and Geomembranesvol 44 no 6 pp 854ndash861 2016

[17] R Alaie and R J Chenari ldquoCyclic and post-cyclic shearbehaviour of interface between geogrid and EPS beads-sandbackfillrdquo KSCE Journal of Civil Engineering vol 22 no 9pp 3340ndash3357 2018

[18] ASTM D5321 Standard Test Method for Determining theCeofficient of Soil and Geosynthetic or Geosynthetic andGeosynthetic Friction by the Direct Shear Method ASTMInternational West Conshohocken PA USA 2002

[19] M L Lopes and R Silvano ldquoSoilgeotextile interface be-haviour in direct shear and pullout movementsrdquo Geotechnicaland Geological Engineering vol 28 no 6 pp 791ndash804 2010


[20] G Zhang and J-M Zhang ldquoExperimental study on behaviorof interface between sand and geotextilerdquo Rock and SandMechanics vol 27 no 1 pp 51ndash55 2006

[21] J-J Wang H-P Zhang S-C Tang and Y Liang ldquoEffects ofparticle size distribution on shear strength of accumulationsoilrdquo Journal of Geotechnical and Geoenvironmental Engi-neering vol 139 no 11 pp 1994ndash1997 2013

[22] Y Xu D J Williams M Serati et al ldquoEffects of scalping ondirect shear strength of crusher run and crusher rungeogridinterfacerdquo Journal of Materials in Civil Engineering vol 30no 9 Article ID 04018206 2018

[23] H-L Wang W-H Zhou Z-Y Yin et al ldquoEffect of grain sizedistribution of sandy soil on shearing behaviors at soilndashstructure interfacerdquo Journal of Materials in Civil Engineeringvol 31 no 10 Article ID 04019238 2019

[24] C J Nye and P J Fox ldquoDynamic shear behavior of a needle-punched geosynthetic clay linerrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 133 no 8 pp 973ndash9832007

[25] C S Vieira M L Lopes and L M Caldeira ldquoSand-geotextileinterface characterisation through monotonic and cyclic di-rect shear testsrdquo Geosynthetics International vol 20 no 1pp 26ndash38 2013


important parameter to study the interface behaviour It wasfound that the frictional behaviour of reinforced soil in-terface was mainly influenced by the properties of soil andproperties of reinforcement

Cyclic direct shear tests are performed to characterizethe interaction near the base of the slope between twomaterials in reinforced soil structures under traffic seismicand other types of cyclic loading Liu et al and Wang et al[2 16] discussed the effect of soil particle size on the cyclicand postcyclic shear behaviour between sand and geogridinterface Alaie and Chenari [17] conducted the monotoniccyclic and postcyclic tests in EPS-sand-geogrid mixturesUnder cyclic direct shear tests there is also a need to un-derstand the interlocking on sand-geotextile interface eeffect of particle-size gradation on cyclic shear strength hasnot been fully studied Furthermore the comparison be-tween monotonic direct shear tests and postcyclic directshear behaviour under the effect of particle-size gradation oncyclic shear tests requires further discussion andinvestigation

e primary objective of this study is to investigate theeffect of sand particle-size gradation on shear behaviours ofthe sand-geotextile interface via laboratory large-scale directshear test e sand used in the tests was classified based onthe grain diameter Both monotonic direct shear (MDS) andcyclic direct shear (CDS) tests were performed under dif-ferent normal stresses e interface shear properties in-cluding shear stiffness damping ratios and shear strengthenvelope were specifically examined in detail

2 Materials and Methods

21 Testing Apparatus e direct shear testing device usedin this study is the ShearTrac-III Large-Scale Direct ShearApparatus designed and constructed by Geocomp edevice consists of an upper box with dimensions of305mmtimes 305mm in length and width and 100mm inheight and a lower box of 305mmtimes 405mm in length andwidth and 100mm in height e maximum horizontaldisplacement is 100mm e lower box is larger than theupper box which ensures a constant contact areathroughout the shearing process e device can apply staticshear as well as cyclic shear and these effects can be eitherload-controlled or displacement-controlled For this studydisplacement-controlled tests were performed e upperbox is fixed in the horizontal direction whereas the lowerbox moves horizontally driven by high-accuracy electricmotors e maximum shearing rate is 15mmmin eloading system shows good control of the normal stressduring testing and even significant volumetric contractionis recorded by a liner variable differential transformer(LVDT) respectively

22 Test Materials e test materialwasselected as thecoarse silica sand with a specific gravity (Gs) of 265 iscoarse sand was divided into four classes by screening forgrain size e particle sizes (diameter) of the four classeswereS1 (05ndash1 mm) S2 (1ndash2 mm) S3 (2ndash4mm) and S4

(4ndash8 mm) According to the Unified Soil ClassificationSystem (USCS) these four classes of coarse sand weremixed in predetermined proportions and classified aswell-graded coarse sand (C1) poorly graded coarse sand(C2) and discontinuously graded coarse sand (C3) ecoefficient of uniformity (Cu) of three samples were 571323 and 172 and the coefficient of curvature (Cc) were143 081 and 087 e particle-size distribution curvesof the sands are presented in Figure 1 e woven geo-textile was used in this paper e properties of thegeotextile are listed in Table 1

23 Testing Procedures A series of CDS MDS and PCDStests were conducted to evaluate shear behaviours of thecoarse sand-geotextile interfaces According to ASTMD5321 [18] the shearing displacement rate was desig-nated as 1 mmmin of 30 60 and 90 kPa for all tests theshear displacement amplitude for the CDS tests wasdesignated as 3 mm and the number of cycles wasdesignated as 10 e top surface of the sand was kept ashorizontal as possible until the specified elevation wasreached at which time the total mass of sand loaded wasrecorded During each test a rigid block was placed in thelower box e geotextilewas fixed over the lower boxwith bolts and steel blocks to ensure that there was norelative displacement between the material and the lowerbox e shear occurred along the sand-geotextile in-terface e validity of the method of placing rigid blocksin the lower box has been demonstrated in [19] ecyclic shear path is shown in Figure 2(a) e lower shearbox moved from the equilibrium position following theshear path ①-②-③-④ which was defined as oneloading cycle After the CDS test was completed thenormal stress applied to the sample was unloaded andreloaded to the target value of the PCDS test e MDStests without cyclic shearing were performed on thereloaded specimens

01 1 100

10

20

30

40

50

60

70

80

90

100

Perc

ent f

iner

Particle size (mm)

C1C2C3

Figure 1 Particle-size distribution curves for the test sands











(kNm)




4Shear displacement

Block

Upper box

405mm

100mm

100mmLower box

305mm


1

23

0

Geotextile

(a)

Time

3T4T4 T2 T0


(b)







C1-geotextile


ndash40

ndash20

0

20

40Sh

ear s

tres

s (kP

a)

(a)

C2-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(b)

C3-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(c)



C1-geotextile

ndash08

ndash06

ndash04

ndash02

00V

ertic

al d

ispla

cem

ent (

mm

)


(a)

C2-geotextile

ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(b)

C3-geotextile

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(c)


ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)








5 Discussion


0

10

20

30

40

50

60

70Sh

ear s

tres

s (kP

a)



(a)


0

10

20

30

40

50

60

70

Shea

r str

ess (

kPa)


(b)



ndash05

ndash04

ndash03

ndash02

ndash01

00

Ver

tical

disp

lace

men

t (m

m)


(a)

ndash020

ndash015

ndash010

ndash005

000

Ver

tical

disp

lace

men

t (m

m)



(b)




K τmax + τmin

2Δa (1)


D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857


(2)



0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile




(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)





C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References





































(kNm)




4Shear displacement

Block

Upper box

405mm

100mm

100mmLower box

305mm


1

23

0

Geotextile

(a)

Time

3T4T4 T2 T0


(b)







C1-geotextile


ndash40

ndash20

0

20

40Sh

ear s

tres

s (kP

a)

(a)

C2-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(b)

C3-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(c)



C1-geotextile

ndash08

ndash06

ndash04

ndash02

00V

ertic

al d

ispla

cem

ent (

mm

)


(a)

C2-geotextile

ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(b)

C3-geotextile

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(c)


ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)








5 Discussion


0

10

20

30

40

50

60

70Sh

ear s

tres

s (kP

a)



(a)


0

10

20

30

40

50

60

70

Shea

r str

ess (

kPa)


(b)



ndash05

ndash04

ndash03

ndash02

ndash01

00

Ver

tical

disp

lace

men

t (m

m)


(a)

ndash020

ndash015

ndash010

ndash005

000

Ver

tical

disp

lace

men

t (m

m)



(b)




K τmax + τmin

2Δa (1)


D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857


(2)



0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile




(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)





C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References
































C1-geotextile


ndash40

ndash20

0

20

40Sh

ear s

tres

s (kP

a)

(a)

C2-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(b)

C3-geotextile


ndash40

ndash20

0

20

40

Shea

r str

ess (

kPa)

(c)



C1-geotextile

ndash08

ndash06

ndash04

ndash02

00V

ertic

al d

ispla

cem

ent (

mm

)


(a)

C2-geotextile

ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(b)

C3-geotextile

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(c)


ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)








5 Discussion


0

10

20

30

40

50

60

70Sh

ear s

tres

s (kP

a)



(a)


0

10

20

30

40

50

60

70

Shea

r str

ess (

kPa)


(b)



ndash05

ndash04

ndash03

ndash02

ndash01

00

Ver

tical

disp

lace

men

t (m

m)


(a)

ndash020

ndash015

ndash010

ndash005

000

Ver

tical

disp

lace

men

t (m

m)



(b)




K τmax + τmin

2Δa (1)


D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857


(2)



0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile




(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)





C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References




























C1-geotextile

ndash08

ndash06

ndash04

ndash02

00V

ertic

al d

ispla

cem

ent (

mm

)


(a)

C2-geotextile

ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(b)

C3-geotextile

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)


(c)


ndash10

ndash08

ndash06

ndash04

ndash02

00

Ver

tical

disp

lace

men

t (m

m)








5 Discussion


0

10

20

30

40

50

60

70Sh

ear s

tres

s (kP

a)



(a)


0

10

20

30

40

50

60

70

Shea

r str

ess (

kPa)


(b)



ndash05

ndash04

ndash03

ndash02

ndash01

00

Ver

tical

disp

lace

men

t (m

m)


(a)

ndash020

ndash015

ndash010

ndash005

000

Ver

tical

disp

lace

men

t (m

m)



(b)




K τmax + τmin

2Δa (1)


D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857


(2)



0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile




(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)





C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References































5 Discussion


0

10

20

30

40

50

60

70Sh

ear s

tres

s (kP

a)



(a)


0

10

20

30

40

50

60

70

Shea

r str

ess (

kPa)


(b)



ndash05

ndash04

ndash03

ndash02

ndash01

00

Ver

tical

disp

lace

men

t (m

m)


(a)

ndash020

ndash015

ndash010

ndash005

000

Ver

tical

disp

lace

men

t (m

m)



(b)




K τmax + τmin

2Δa (1)


D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857


(2)



0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile




(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)





C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References





























K τmax + τmin

2Δa (1)


D ΔW

2π τ2max2K( 1113857 + τ2min2K( 1113857( 1113857


(2)



0

20

40

60Sh

ear s

tres

s (kP

a)

C1-geotextile




(a)

C2-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(b)

C3-geotextile

0

20

40

60

Shea

r str

ess (

kPa)




(c)





C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References






























C1-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(a)

C2-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(b)

C3-geotextile

ndash04

ndash02

00

02

04

Ver

tical

disp

lace

men

t (m

m)




(c)


K

Shear stress (τ)

Displacement (∆)

ndash∆a ∆a

τmax

A2

τmin

1∆W





8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References






























8

9

10

11

12Sh

ear s

tiffne

ss K

(MPa

m)



(a)

044

045

046

047

048

Dam

ping

ratio

D



(b)


30 40 50 60 70 80 9020

25

30

35

40

45

50

55

60

65

τ = 1814 + 0396σR2 = 09682

τ = 769 + 0550σR2 = 09967

Shea

r str

ess (

kPa)


τ = 835 + 0579σR2 = 09998


(a)

τ = 1679 + 0401σR2 = 09961

τ = 1474 + 0460σR2 = 09743

τ = 1350 + 0555σR2 = 09975

25

30

35

40

45

50

55

60

65

Shea

r str

ess (

kPa)



(b)








Data Availability




Acknowledgments


References

































Data Availability




Acknowledgments


References




























effect of particle-size gradation on coarse sand-geotextile … · 2020. 9. 3. · test. among the...

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