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Geotextiles and Geomembranes 26 (2008) 512–518

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Geotextiles and Geomembranes

journal homepage: www.elsevier .com/locate/geotexmem

Mechanical behavior of lightweight soil reinforced with waste fishing net

Y.T. Kim a,*, H.J. Kim a, G.H. Lee b

a Department of Ocean Engineering, Pukyong National University, Busan 608-737, Republic of Koreab Department of Civil Engineering, Kongju National University, Cheonan, Republic of Korea

a r t i c l e i n f o

Article history:Received 13 October 2007Received in revised form 22 March 2008Accepted 4 May 2008Available online xxx

Keywords:Lightweight soilWaste fishing netUnconfined compressive strength

* Corresponding author. Tel.: þ82 51 629 6587; faxE-mail address: yuntkim@pknu.ac.kr (Y.T. Kim).

0266-1144/$ – see front matter Crown Copyright � 2doi:10.1016/j.geotexmem.2008.05.004

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a b s t r a c t

Lightweight soil is cement-treated and consists of dredged clayey soil, cement, and air-foam. Reinforcedlightweight soil (RLS) contains waste fishing net to increase its shear strength. This paper investigates thestrength characteristics and stress–strain behavior of reinforced and unreinforced lightweight soils. Testspecimens were prepared with varying admixtures of cement content (8%, 12%, 16%, and 20% by theweight of untreated soil), initial water content (125%, 156%, 187%, 217%, and 250%), air-foam content (1%,2%, 3%, 4%, and 5%), and waste fishing net (0%, 0.25%, 0.5%, 0.75%, and 1%). Then several series of un-confined compression tests and one-dimensional compression tests were conducted. The experimentswith lightweight soil indicated that the unconfined compressive strength increased with an increase incement content, but decreased with increasing water content and air-foam content. The stress–strainrelationship and the unconfined compressive strength were influenced by the percentage of wastefishing net. In addition, the strength of RLS generally increased after adding waste fishing net due to thebond strength and the friction at the interface between waste fishing net and soil mixtures, but theamount of increase in compressive strength was not directly proportional to the percentage of wastefishing net. The results of testing indicated that the maximum increase in compressive strength wasobtained for a waste fishing net content of about 0.25%. The bulk unit weight of lightweight soil wasstrongly dependent on the air-foam content. The compression characteristics of lightweight soil, in-cluding the yield stress and compression index, did not depend greatly on whether the samples werecured underwater or in air.

Crown Copyright � 2008 Published by Elsevier Ltd. All rights reserved.

1. Introduction

A large amount of soft soil has been dredged from navigationchannels and construction sites of large-scale port and harborprojects such as Busan New Port, Korea. Most of the dredged ma-terial is clayey soil with high water content that is too soft to beused for backfilling material without some type of processing. Fig. 1illustrates the annual generation of dredged soil from 1990 to 2004in Busan, Korea, where the continuous increase is due to largeconstruction projects associated with new industrial complexes.Dredged soil is usually dumped in waste disposal sites at sea. This,however, is becoming increasingly difficult due to environmentalconsiderations and pressure has been increasing to reuse thedredged soil in port and harbor construction projects.

Cement-treated lightweight soil was developed in Japan(Tsuchida, 1995; Tsuchida et al., 1996) as a means of reusingdredged soil for construction material. Lightweight soil consists ofdredged clayey soil, cement, and a lightening material, as shown in

: þ82 51 629 6590.

008 Published by Elsevier Ltd. All

et al., Mechanical behavior omem.2008.05.004

Fig. 2(a). Lightweight soil has low unit weight as well as high shearstrength. The low unit weight, typically 6–15 kN/m3, is a result ofincorporating lightening materials such as air-foam or expandedpolystyrol beads. This makes the lightweight soil useful as a back-filling material to compensate for its high cost and reduces theoverburden stress applied to underlying compressible soils. Light-weight treated soil is relatively homogeneous compared to naturalsoil, and its density can be adjusted by varying the amount of air-foam mixed with soil. The density shows an increasing tendency bydefoaming of the air-foam before hardening and by the waterpressure during underwater curing (Tsuchida and Egashira, 2004).

The shear strength of lightweight soil greatly depends on theamount of cementing agent added. The more cementing agent thatis added to the mixture, the greater its unconfined compressivestrength (qu) (Tsuchida and Egashira, 2004). Lightweight soil hasbeen used in various applications in Japanese coastal constructionprojects to reduce both the overburden stress on undergroundstructures and lateral earth pressure acting on retaining structures(Tsuchida et al., 2000; Otani et al., 2002; Tsuchida and Kang, 2002,2003; Watabe et al., 2004).

Waste fishing net also causes environmental problems in thefishing grounds along coastal areas. Table 1 shows the annual

rights reserved.

f lightweight soil reinforced with waste fishing net, Geotextiles and

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

Volu

me

of d

redg

ed s

oil (

m3 )

1990 1992 1994 1996 1998 2000 2002 2004

Year

Fig. 1. Annual generation of dredged soil.

Y.T. Kim et al. / Geotextiles and Geomembranes 26 (2008) 512–518 513

ARTICLE IN PRESS

amount of waste collected for a 3-year period. According to datareleased by the Ministry of Maritime Affairs and Fisheries in 2001,about 20,000 tons of waste fishing net are collected annually,which is not reused due to inadequate recycling techniques.

The concept of reinforced lightweight soil (RLS) using wastefishing net was developed to address the recycling of both dredgedsoils and waste fishing net. Reinforcing elements such as strips,fabrics, fibers, and grids increase the shear resistance of compositematerials and change their brittle behavior into ductile behavior(Vidal, 1969; Gray and Al-Refeai, 1986; Kaniraj and Havanagi, 2001;Prabakar and Sridhar, 2002; Kaniraj and Gayathri, 2003; Yetimogluand Salbas, 2003; Park and Tan, 2005; Yetimoglu et al., 2005; Zhanget al., 2006, 2008; Long et al., 2007; Sawwaf, 2007; Tang et al.,2007). Yetimoglu and Salbas (2003) investigated the effect of thefiber reinforcement content on the shear strength of sand using thedirect shear test. They reported that the peak shear strength andinitial stiffness of sand reinforced with randomly distributed fiberwere not affected significantly by the fiber reinforcement. However,fiber reinforcement reduced soil brittleness, provided a smaller lossof post-peak strength, and increased the residual shear strengthangle of the sand.

In this study, the mechanical behavior of RLS was investigatedusing laboratory tests such as the unconfined compression test andthe one-dimensional compression test. RLS was made fromdredged clayey soil, cement, air-foam, and waste fishing net. Lab-oratory tests were performed to evaluate the reinforcing effect ofwaste fishing net in RLS by comparing the compressive behavior ofRLS and unreinforced lightweight soil. The main objective of thisinvestigation focused on the strength characteristics of RLS, with

Air-foam

Dredged

Cemen

Wastefishing

unreinforceda

Fig. 2. Schematic diagram of (a) unreinforce

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waste fishing net randomly included in the soil mixture at fivedifferent percentages.

2. Experimental study of RLS

Fig. 2 illustrates the schematic diagram of unreinforced andreinforced lightweight soils. In order to increase the unconfinedcompressive strength of lightweight soil as well as recycle wastefishing net, waste fishing net was added to lightweight soil asshown in Fig. 2(b). RLS consists of dredged clayey soil, cement, air-foam, and waste fishing net.

Table 2 lists the geotechnical properties of the dredged clayeysoil from the construction site of Busan New Port, Korea. The nat-ural water content of the dredged clayey soil is about 125%, and itsliquidity index is about 7.4. The dredged soft clay is classified as lowplasticity clay, CL, according to the Unified Soil Classification System(USCS). Ordinary Portland cement was used in this study asa cementing agent. A protein-type foaming agent that expands 20times in volume, similar to shaving cream, was used as the light-ening material.

As shown in Table 3, several types of specimen were prepared.Various mixing conditions were used to investigate the effects onthe compressive strength of various levels of cement, water, andair-foam content. Cement was uniformly added into the soil mix-ture at four different concentrations (8%, 12%, 16%, and 20% byweight of untreated soil). The water content varied between 125%and 250% and the air-foam content varied from 1% to 5% by weightof untreated soil. To evaluate the reinforcing effect of waste fishingnet on the strength of lightweight soil, the net was randomly in-cluded in the soil mixture at five different percentages (0, 0.25%,0.5%, 0.75%, and 1% by weight of untreated soil).

Table 4 shows the properties of the polyethylene waste fishingnet used in this study. The polyethylene waste fishing net mesh sizewas 2.2 cm� 2.2 cm, with a 0.8 mm diameter and tensile strengthof about 120 kN/m. The waste fishing net was cut into rectanglesabout 5 cm� 4 cm to fit the size of the mold, and was simply addedand carefully mixed by hand with the soil mixture to achievea relatively uniform consistency. Then, the slurry mixture wasplaced into a mold with a diameter of 72 mm and height of148 mm, and cured at a constant temperature of 20� 2 �C.

The effect of the confining stress on the peak shear strength wasnegligible in the cement-treated soil because most of the shearstrength was developed by hardening or cementation (Watabeet al., 2001). Therefore, in this study, unconfined compression testswere conducted at curing times of 7, 14, and 28 days. The soilspecimen is typically sheared in a controlled strain apparatus ata strain rate of 0.5–2% axial strain per minute. In this study, an

soil

t

net

reinforced with waste fishing net b

d and (b) reinforced lightweight soils.

f lightweight soil reinforced with waste fishing net, Geotextiles and

Table 3Mixing conditions

Type Mixing condition (%a)

Cement content (Ci) 8, 12, 16, 20Water content (Wi) 125, 156, 187, 217, 250Air-foam content (Ai) 1, 2, 3, 4, 5Waste fishing net content (Ni) 0, 0.25, 0.5, 0.75, 1

a Percentage by the weight of untreated soil.

Table 4Properties of the waste fishing net used

Material Polyethylene (PE)

Mesh size (cm) 2.2� 2.2Diameter (mm) 0.8Tensile strength (kN/m) 120

Table 1Annual amount of waste collection (Ministry of Maritime Affairs and Fisheries ofKorea, 2001) (unit: tons)

Year Total Waste Styrofoam Fishing net Shell Other

1998 343,845 36,427 1712 19,160 254,783 31,7631999 107,726 24,153 44,124 21,650 3286 14,5132000 87,341 31,591 5027 21,761 11,476 17,486

Table 2Properties of dredged soil

Initial watercontent (%)

Liquidlimit (%)

Plasticlimit (%)

Specificgravity

Percentpassing no.200 sieve (%)

USCS

125 39.2 18.5 2.60 81.2 CL

Y.T. Kim et al. / Geotextiles and Geomembranes 26 (2008) 512–518514

ARTICLE IN PRESS

unconfined compression test on the specimens was conducted ata strain rate of about 1.0% per minute. One-dimensional compres-sion tests were also performed to investigate the compressioncharacteristics of underwater curing and air curing of the light-weight soil specimen.

3. Experimental results and discussion

3.1. Bulk unit weigh

Bulk unit weight is one of the important characteristics oflightweight soil. Fig. 3 shows the bulk unit weight of lightweightsoils as a function of the percentage of admixture materials such ascement, water, and air-foam. The reference specimen had a cementcontent of 12%, a water content of 156%, and an air-foam content of2%. For example, Fig. 3(a) shows the bulk unit weight of lightweight

Un

it w

eig

ht (k

N/m

3)

8

9

10

11

12

13

0 1.5

Air-foam

c

8

9

10

11

12

13

5 10 15 20 25Cement content (%)

Un

it w

eig

ht (k

N/m

3)

a b

Fig. 3. Bulk unit weight as a function of (a) cem

Please cite this article in press as: Kim, Y.T., et al., Mechanical behavior oGeomembranes (2008), doi:10.1016/j.geotexmem.2008.05.004

soils for various cement contents in the range 8–20% with a con-stant water content of 156% and air-foam content of 2%. Fig. 3 showsthat the bulk unit weight increased slightly with an increase incement content, but decreased slightly with an increase in watercontent. However, the value of the bulk unit weight decreased from12.5 kN/m3 for an air-foam content of 1% to 8.5 kN/m3 for an air-foam content of 5%. This indicates that the bulk unit weight oflightweight soil is strongly dependent on the air-foam content ofthe soil mixture.

3.2. Stress–strain behavior

The stress–strain behavior of lightweight soils with variousadmixture conditions such as cement, initial water, and air-foamcontent is shown in Fig. 4. The compressive stress of lightweightsoil increased with an increase in axial strain up to a certain peak.The maximum compressive strength of cement-mixed lightweight

3 4.5 6

content (%)

Un

it w

eig

ht (k

N/m

3)

8

9

10

11

12

13

100 150 200 250 300Water content (%)

ent, (b) water, and (c) air-foam percentages.

f lightweight soil reinforced with waste fishing net, Geotextiles and

0

20

40

60

80

100

0 2 4 6 8 10

Axial strain (%)

0 2 4 6 8 10

Axial strain (%)

0 2 4 6 8 10

Axial strain (%)

Un

co

nfin

ed

co

mp

ressive

stress (kP

a)

Ci-8%Ci-12%Ci-16%Ci-20%

0

10

20

30

40

50

Un

co

nfin

ed

co

mp

res

sive

stress (kP

a)

Wi-125%Wi-156%Wi-187%Wi-218%Wi-250%

0

20

40

60

80

100

Un

co

nfin

ed

co

mp

ressive

stress (kP

a)

Ai-1%Ai-2%Ai-3%Ai-4%Ai-5%

a

b

c

Fig. 4. Stress–strain behavior as a function of (a) cement, (b) water, and (c) air-foampercentages.

Un

co

nfin

ed

c

om

pre

ss

iv

e s

tre

ss

(kP

a)

140

20

1086Axial strain (%)

420

120

100

80

60

40

0

160

180Ni – 0%, Tc – 7days Ni – 0%, Tc – 28daysNi – 0.25%, Tc – 7days Ni – 0.25%, Tc – 28days

Fig. 5. Stress–strain behavior of reinforced and unreinforced lightweight soils asa function of fishing net content (Ni) and curing time (Tc).

Tension

Cement

Wastefishing net

Dredged soil

Traction around RLS body

Air-foam

Fig. 6. Conceptual diagram of mechanical behavior at the interface between the fibersurface and soil mixtures.

Y.T. Kim et al. / Geotextiles and Geomembranes 26 (2008) 512–518 515

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soil occurred at an axial strain range of 2–4%. After reaching thepeak strength, the unconfined compressive stress decreased withincreasing axial strain, and strain softening occurred. As shown inFig. 4, the unconfined compressive strength of lightweight soilsincreased with an increase in cement content, but decreased withincreased water and air-foam content.

The stress–strain relationships of RLS and unreinforced light-weight soil for curing times of 7 and 28 days are presented in Fig. 5.The stress–deformation response was affected by the curing timeand waste fishing net content. The unconfined compressivestrengths of both RLS and unreinforced lightweight soil were pro-portional to the curing time. The strain at the peak strength de-creased from 4% at a curing time of 7 days to about 2.6% at 28 days.For RLS, the reductions from the peak strength to that under a large

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strain were 38 kPa for a curing time of 7 days and 75 kPa fora curing time of 28 days, as shown in Fig. 5. These results indicatethat cement-treated lightweight soil tends to be more brittle withan increase in curing time.

In the case of a waste fishing net content of 0.25%, the un-confined compressive strengths of RLS were about 2–2.5 timesgreater than those of unreinforced lightweight soils due to thereinforcing effect of the net. Fig. 6 presents a conceptual diagramof the mechanical behavior at the interface between the fishingnet and the soil mixtures. External forces cause relative move-ment in the soil mixture, which produces tension in the netrunning through it. As a result, the shear strength of fiber-mixedsoil increases due to the bond strength and the friction at theinterface between the net and the soil mixture, as shown inFig. 6. The interaction between the fishing net and the soilmixture is one of important factors that control the behavior ofthe RLS. Tang et al. (2007) also showed that the bond strengthand friction at the interface is the dominant mechanism con-trolling this reinforcement.

f lightweight soil reinforced with waste fishing net, Geotextiles and

0

40

80

120

160

200

0 5 10 15 20 25 30Curing time (days)

Un

co

nfin

ed

c

om

pre

ss

iv

e s

tre

ng

th

(k

Pa

)

Ni-0%Ni-0.25%Ni-0.5%Ni-0.75%Ni-1%

Fig. 7. Compressive strength as a function of curing time and net content (Ni).

0

30

60

90

120

150

180

0 0.2 0.4 0.6 0.8 1 1.2Waste fishing net content (%)

Un

co

nfin

ed

co

mp

ressive stren

gth

(kP

a)

Tc-7daysTc-14daysTc-28days

Fig. 9. Variation of compressive strength with waste fishing net content and curingtime.

Y.T. Kim et al. / Geotextiles and Geomembranes 26 (2008) 512–518516

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3.3. Unconfined compressive strength

Fig. 7 shows the unconfined compressive strength (qu) asa function of curing time. The value of qu of the cement-treatedmixture rapidly increased at the beginning of the curing time due tothe cementation effect and then increased more gradually after 7days.

The relationship between the unconfined compressivestrengths at 28 days (qu28) and 7 days (qu7) of curing time is shownin Fig. 8. The correlation coefficient obtained from regressionanalysis was about 0.96, indicating a good correlation between qu28

and qu7. Therefore, qu28 could be estimated as

qu28 ¼ 1:72qu7: (1)

Fig. 9 illustrates the unconfined compressive strength asa function of waste fishing net content for three curing times. Theselaboratory testing results indicated that the unconfined compres-sive strength of RLS generally increased when waste fishing net wasadded due to the bond strength and the friction at the interfacebetween the net and soil mixtures; the amount of increase incompressive strength, however, was not directly proportional tothe net content. In this test, the maximum increase in the un-confined compressive strength was obtained for a fishing netcontent of about 0.25%. Similar results were reported by Prabakarand Sridhar (2002). They used triaxial compression tests to in-vestigate the strength behavior of the soil reinforced with ran-domly included sisal fiber at four different content levels (0.25%,

qu28 = 1.7161qu7R = 0.9554

0

30

60

90

120

150

180

0 20 40 60 80 100q

u7 (kPa)

qu

28 (kP

a)

Fig. 8. Relationship of the compressive strength at curing times of 7 and 28 days.

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0.5%, 0.75%, and 1.0% by weight of untreated soil). Their testsshowed a significant improvement in shear strength parameterssuch as cohesion and the internal friction angle of the soil. Thepercentage of fiber content also influenced the shear strength asthe shear stress increased nonlinearly with the increase in fibercontent. However, for a fiber content greater than 0.75%, the shearstress decreased due to the reduction of density in the soil fibermass.

3.4. Compression characteristics

Fig. 10 presents the effective stress–void ratio curves from one-dimensional compression tests carried out on the lightweight soilsample. Two specimens were cured underwater without appliedpressure, and three specimens were cured in air, all for 28 days.While the admixtures of five specimens were the same, the curingconditions were different. Compression pressure from 10 kPa to1280 kPa was applied in eight stages with an incremental loadingratio of 1 as shown in Fig. 10. Loading increments were 10 kPa,20 kPa, 40 kPa, 80 kPa and so on, and each load incrementremained on the soil specimen for 24 h.

The initial void ratios of air-cured specimens were slightly lessthan the ratios of those cured underwater. This may have been dueto shrinkage caused by drying. The void ratio decreased slightlywith an increase in effective stress up to the yield point and thendecreased rapidly as the structure or cemented bond of the mixturestarted to collapse due to the yield stress. However, the yield stress

3.0

3.5

4.0

4.5

5.0

5.5

6.0

1 10 100 1000 10000Effective stress (kPa)

Vo

id

ra

tio

Underwater curing 1Underwater curing 2Air curing 1Air curing 2Air curing 3

Fig. 10. Effective stress–void ratio curve for lightweight soil.

f lightweight soil reinforced with waste fishing net, Geotextiles and

0

4,000

8,000

12,000

16,000

0 40 80 120 160 200

qu (kPa)

E50

(kP

a)

ReinforcedUnreinforced

Tang et al. (1996)E50 = (40~260)qu

E50 =44qu

E50 =53qu

E 50=14

1q u

E 50 =80q u

Fig. 11. Relationship between the secant modulus and unconfined compressivestrength.

Y.T. Kim et al. / Geotextiles and Geomembranes 26 (2008) 512–518 517

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and compression index of lightweight soil samples were almost thesame for both underwater- or air-curing conditions. Horpibulsuket al. (2004) reported similar results in which the compressibility ofa given cement-admixed clay at post-yield was governed mainly bythe cement content, irrespective of water content. The compressionof specimens may result from the compression of air and rear-rangement of particles caused by bond breakage.

3.5. Secant modulus

The relationship between the secant modulus (E50) and theunconfined compression strength (qu) of lightweight soils is shownin Fig. 11. The secant modulus denotes the slope of the line betweenthe origin and the point qu/2 on the stress–strain curve. The E50 ofunreinforced lightweight soil was in the range of 44–80qu and theE50 of RLS was in the range of 53–141qu, as shown in Eq. (2). Theresults indicate that the stiffness of RLS was slightly greater thanthat of unreinforced lightweight soil due to the reinforcing effect ofthe waste fishing net. Tang et al. (1996) reported that E50 was in therange of 40–260 times the value of qu, and tended to decrease as thetotal confining pressure increased:

E50 ¼ aqu; (2a)

a ¼ 44—80ðunreinforcedÞ; (2b)

a ¼ 53—141ðreinforcedÞ: (2c)

4. Conclusions

Several series of laboratory tests were performed to evaluate themechanical behavior of RLS and unreinforced lightweight soils. RLSwas made of dredged clayey soil, cement, air-foam, and wastefishing net. From this experimental study, the following conclu-sions were drawn.

1. The unconfined compressive strengths of lightweight soils in-creased with an increase in cement content, but decreased withincreases in water content and air-foam content. The bulk unitweight was strongly dependent on the air-foam content of thesoil mixture.

2. The unconfined compressive strength of RLS generally in-creased after adding waste fishing net due to the bond strength

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and the friction at the interface between the net and soilmixtures, but the amount of increase in compressive strengthwas not directly proportional to the percentage of net. In thisstudy, the maximum increase in unconfined compressivestrength was obtained for a fishing net content of 0.25%.

3. The compression characteristics of lightweight soil such asyield stress and compression index did not depend greatly onwhether the samples were cured underwater or in air.

4. The secant moduli (E50) of unreinforced lightweight soil andRLS were in the range of 44–80qu and 53–141qu, respectively.

Acknowledgment

This work was partially supported by the Korea ResearchFoundation Grant funded by the Korean Government (MOEHRD)(KRF-2006-311-D00877).

References

Gray, D.H., Al-Refeai, T., 1986. Behaviour of fabric- versus fiber-reinforced sand.Journal of Geotechnical Engineering, ASCE 112 (8), 804–820.

Horpibulsuk, S., Bergado, D.T., Lorenzo, G.A., 2004. Compressibility of cement-admixed clays at high water content. Geotechnique 54 (2), 151–154.

Kaniraj, S.R., Gayathri, V., 2003. Geotechnical behavior of fly ash mixed withrandomly oriented fiber inclusions. Geotextiles and Geomembranes 21 (3),123–149.

Kaniraj, S.R., Havanagi, V.G., 2001. Behavior of cement-stabilized fiber-reinforced flyash–soil mixtures. Journal of Geotechnical and Geoenvironmental Engineering,ASCE 127 (7), 574–584.

Long, P.V., Bergado, D.T., Abuel-Naga, H.M., 2007. Geosynthetics reinforcementapplication for tsunami reconstruction: evaluation of interface parameters withsilty sand and weathered clay. Geotextiles and Geomembranes 25 (4–5),311–323.

Ministry of Maritime Affairs and Fisheries of Korea, 2001. Fact Book of MaritimeAffairs and Fisheries (in Korean).

Otani, J., Mukunoki, T., Kikuchi, Y., 2002. Visualization for engineering property ofin-situ light weight soils with air foams. Soils and Foundations 4 (3), 93–105.

Park, T., Tan, S.A., 2005. Enhanced performance of reinforced soil walls by theinclusion of short fiber. Geotextiles and Geomembranes 23 (4), 348–361.

Prabakar, J., Sridhar, R.S., 2002. Effect of random inclusion of sisal fibre on strengthbehavior of soil. Construction and Building Materials 16, 123–131.

Sawwaf, M.A.E., 2007. Behavior of strip footing on geogrid-reinforced sand overa soft clay slope. Geotextiles and Geomembranes 25 (1), 50–60.

Tang, C., Shi, T., Gao, W., Chen, F., Cai, Y., 2007. Strength and mechanical behavior ofshort polypropylene fiber reinforced and cement stabilized clayed soil.Geotextiles and Geomembranes 25 (3), 194–202.

Tang, Y.X., Tsuchida, T., Shirai, A., Ogata, H., Shiozaki, K., 1996. Triaxial compressioncharacteristics of super geo-material cured underwater. In: Proceedings of the31st Conference on Geotechnical Engineering, pp. 2493–2494.

Tsuchida, T., 1995. Super geo-material project in coastal zone. In: Proceedings of theInternational Symposium on Ocean Space Utilization COSU’95, Yokohama, pp.22–31.

Tsuchida, T., Egashira, K., 2004. The Lightweight Treated Soil MethoddNew Geo-materials for Soft Ground Engineering in Coastal Areas. A.A. Balkema Publisher,London.

Tsuchida, T., Fujisaki, H., Makibuchi, M., Shinsha, H., Nagasaka, Y., Hikosaka, K.,2000. Use of light-weight treated soils made of waste soil in airport extensionproject. Journal of Construction Management and Engineering, JSCE 644(VI-46), 3–23 (in Japanese).

Tsuchida, T., Kang, M.S., 2002. Use of lightweight treated soil method in seaport andairport construction projects. In: Proceedings of the Nakase Memorial Sympo-sium, Soft Ground Engineering in Coastal Areas. A.A. Balkema, Yokosuka, pp.353–365.

Tsuchida, T., Kang, M.S., 2003. Case studies of lightweight treated soil method inseaport and airport construction projects. In: Proceedings of the 12th AsianRegional Conference on Soil Mechanics and Geotechnical Engineering, Singa-pore, pp. 249–252.

Tsuchida, T., Takeuchi, D., Okumura, T., Kishida, T., 1996. Development oflight-weight fill from dredgings. In: Environmental Geotechnics. Balkema, pp.415–420.

Vidal, H., 1969. The Principle of Reinforced Earth. Highway Research Record No. 282.Watabe, Y., Furuno, T., Tsuchida, T., 2001. Mechanical properties of dredged soil

treated with low quantity of cement. Journal of Geotechnical Engineering, JSCE694 (III-57), 331–342 (in Japanese).

Watabe, Y., Itou, Y., Kang, M.S., Tsuchida, T., 2004. One-dimensional compression ofair-foam treated lightweight geo-material in microscopic point of view. Soilsand Foundations 44 (6), 53–67.

f lightweight soil reinforced with waste fishing net, Geotextiles and

Y.T. Kim et al. / Geotextiles and Geomembranes 26 (2008) 512–518518

ARTICLE IN PRESS

Yetimoglu, T., Inanir, M., Inanir, O.E., 2005. A study on bearing capacity of randomlydistributed fiber-reinforced sand fills overlying soft clay. Geotextiles and Geo-membranes 23 (2), 174–183.

Yetimoglu, T., Salbas, O., 2003. A study on shear strength of sands reinforcedwith randomly distributed discrete fibers. Geotextiles and Geomembranes 21,103–110.

Please cite this article in press as: Kim, Y.T., et al., Mechanical behavior oGeomembranes (2008), doi:10.1016/j.geotexmem.2008.05.004

Zhang, M.X., Javadi, A.A., Min, X., 2006. Triaxial tests of sand reinforced with 3Dinclusions. Geotextiles and Geomembranes 24 (4), 201–209.

Zhang, M.X., Zhou, H., Javadi, A.A., Wang, Z.W., 2008. Experimental and theo-retical investigation of strength of soil reinforced with multi-layer horizon-tal–vertical orthogonal elements. Geotextiles and Geomembranes 26 (1),1–13.

f lightweight soil reinforced with waste fishing net, Geotextiles and