J. Biomedical Science and Engineering, 2009, 2, 254-260
doi: 10.4236/jbise.2009.24039 Published Online August 2009 (http://www.SciRP.org/journal/jbise/
Published Online August 2009 in SciRes. http://www.scirp.org/journal/jbise
Research on anti-seepage properties of geosynthetic
clay lines in landfills
Xiao-Bo Xiong1, Guo-Qing Gui1, Shu-Zhi Ma2
1School of Engineering, Jinggangshan University, Ji’an, China; 2School of Engineering, China University of Geosciences, Wuhan, China
Email: thongtao2006@163.com; JHBMSZ@163.com
Received 23 February 2009; revised 20 March 2009; accepted 26 March 2009.
In recent years, geosynthetic Clay liners (GCLs)
are widely used in different kinds of anti-seep-
age projects and the anti-seepage availabilities
of GCLs are regarded as increasingly important
by engineers. Anti-seepage effectiveness of
GCLs involves at least two aspects, such as
Hydraulic conductivity of GCLs under engi-
neering practice conditions, and Absorption
ability of bentonite in GCLs in the course of liq-
uid permeation. In this paper, Hydraulic con-
ductivity tests are performed to obtain seepage
coefficient of GCLs, taking liquids such as dis-
tilled, deioned water and landfill leachate, and
solutions with single-species cation as the hy-
dration and permeation liquid. The results Show
that cation valence, cation concentration and
hydration ionic radius in hydration and permea-
tion liquids have influences on hydraulic con-
ductivity of GCLs.
Keywords: Landfills; GCLs; Lines System; Lmper-
vious Barrier; Experimental Analysis
Along with the rapid economic development and ur-
banization, the generation of municipal solid waste
(MSW) increased drastically in China. Landfill is a pri-
mary method of ultimate disposition of municipal solid
waste in many countries. The impervious barrier of
cover system and lines system is the key to ensure that
the landfills should not be the source of secondary pollu-
tion to the surrounding. Applications of geosynthetics,
such as geotextile, geomembrance, GCLs, geonet (GN),
geocomposite (GC) and geofoam (GF), etc., they are
used to all aspects of landfill as liners and covers. With
regard to GCLs as a new type material of seepage barrier,
the authors present here some information on the com-
position of material, engineering characteristic, and
make suggestion on the future development of this
technology. It was investigated that the leakage preven-
tion structures of 56 landfill sites for domestic wastes in
China, and the results showed that leakage prevention
structures were found designed improperly and leakages
happened incidentally in landfills in China. Overseas
experts have already acquired certain research on prop-
erties of GCLs, but research on this product is rare in our
country. In this paper, we studied the properties of GCLs
by means of testing, then points out that making use of
GCLs is the trend of the applicable liner in future.
The protection liners system of clay layer was widely
used in USA before 1982. The new type of geosynthetics
named GCLs come out in 1987 at a Germany company.
In 1989, GCLs was widely applied in sanitary landfills
in USA. And since 1995, the national code for the new
type liner material was taken to draw up, which was fin-
ished in 1999 completely. Before 2000, only one docu-
ment was found during the literature survey that dis-
cusses the performance of GCLs when installed as a
single in-service liner (Lichtwardt and Comer, 1997).
Horace Moo-Young et al. (2004) reviews the state of
the science and practice on the infiltration rate through
compacted clay liner (CCL) for 149 sites and geosyn-
thetic clay liner (GCL) for 1 site. The field hydraulic
conductivities for natural clay liners range from
1×10-9cm s-1 to 1×10-4cm s-1, with an average of
6.5×10-8cm s-1. There was limited information on GCL.
For composite lined and geomembrane systems, the leak
detection system flow rates were utilized. The average
monthly flow rate for composite liners ranged from 0~32
l/hd for geomembrane and GCL systems. A GCL was
installed on the bottom of a salinity-gradient solar pond
in Texas in 1994. The pond has a surface area of ap-
proximately 1 acre (0.4 ha) and a water depth averaging
3.2 m. The GCL is a modified Gundseal, with a 30 mil
(0.07cm) flexible polypropylene geomembrane backing
with 0.5cm of bentonite clay bonded to one side. The
performance of the GCL is presented as the variation in
G. G. Adams et al. / J. Biomedical Science and Engineering 2 (2009) 254-260 255
SciRes Copyright © 2009 JBiSE
hydraulic conductivity of the GCL over time for a 9-
week period. The hydraulic conductivity remains fairly
constant at 2×106 cm s1. This represents an increase
over the initial conductivity, which was measured at
1×106 cm s1. In general, a GCL is most effective when
placed under an effective overburden pressure where the
minimum permeability can be obtained. This data set
clearly indicates that additional research needs to be
conducted to quantify the field infiltration rate of GCLs
in landfills.
In China, Zhou Z. B. (2002) present the condition,
mechanism and process of ion exchange between the
ions of bentonite in the GCL and ions in leachate and
their effects on GCL's impermeability, and some resolu-
tion methods. Yao Q. (2003) introduced design of im-
pervious system of landfill and use of various impervi-
ous materials. Wang X. Q. (2004) analyzed the foreign
application of geomembrane liner system and it is useful
for landfill construction in China. Li Z. B. (2005) ad-
vanced a series of problems which needed to be deeply
researched based on the research achievements by home
and overseas scholars. Liu H. B. (2006) provided the
background and basis for developing standard “Geosyn-
thetic Clay Liner” and details product classification, test
items and methods and performance index. LU H. Y.
(2007) introduced the advantages of GCL serving as an
anti-seepage system of hazardous waste landfill sites and
demonstrates that the anti-seepage result of GCLs is
better than CCLs. The study shows that all the indexes
and benefits from this technique are much better than
those from the traditional anti-seepage technique (Ta-
A GCL is a factory-manufactured, hydraulic barrier
typically consisting of bentonite clay, supported by geo-
textiles and/or geomembranes held together by needling,
stitching, or chemical adhesives. GCLs are typically
used in areas where clay is not readily available or where
conserving air space is an important factor. GCLs do not
have the level of long-term field performance data that
are available for GMs or CCLs because GCLs were de-
veloped recently (1986) and they are typically used with
a GM in a composite liner system.
In recent years, GCLs is widely used in different kinds
Table 1. Statistics of anti-seepage engineering for man-made
lake with GCLs in China.
ProvinceNumbers Area/m2 Province NumbersArea/m2
Beijing 9 167398 Shanghai 37 95907
Zhejiang28 138385 Jiangsu 22 77213
Tianjing1 7000Anhui 6 18395
Hubei 3 7280Shanxi 1 6000
Guangdong4 13240Yunnan 3 18220
Guangxi1 20000Jiangxi 2 7254
Gansu 1 10000Chongqing 1 15000
Neimenggu1 25000Hebei 1 50000
of anti-seepage projects, and the anti-seepage availabil-
ities of GCLs are regarded as increasingly important by
engineers. The four basic GCLs list as follows (see Fig-
ure 1), that is: two layer of GT/GM with bentonite and
bonding agent(binder), two layer of GT/GM with ben-
tonite and stitch fiber, two layer of GT/GM with bentonite
and mending fiber, one layer of GT/GM(beneath the ben-
tonite) with bentonite, etc.
Anti-seepage effectiveness of GCLs involves at least
three aspects: 1) Hydraulic conductivity of GCLs; 2)
Absorption ability of bentonite in GCLs in the course of
liquid permeation; 3) GCL internal shear strength while
used in anti-seepage system.
The above aspects are so important that they could
directly affect the factor of safety and effectiveness of
anti-seepage project. Section of composite liner system
landfill of MSW sanitary landfill (see Figure 2), Section
of the cap of MSW sanitary landfill (see Figure 3).
In this paper, GCLs for indoors tests was made from
the non-fabricated textile factory in Yixing city in ji-
angsu province, and two layer of GT/GM of bentonite
(made by the CETCO Company, USA) with stitching in
two geotextile fibers layer, it belongs to the type of
Bentomat (see in Figure 1, the second graph). The total
mass is 5.32kg/m2 per unit area, with the lower GT is a
kind of fabricated GT whose mass is 112g/m2 per unit
area, and with the upper GT is a kind of non-fabricated
GT whose mass is 221g/m2 per unit area.
Chemical components of Bentomat are: SiO2 57.23%;
Al2O3 18.45%; Fe2O2.57%; FeO 1.19%; MgO 2.22%;
CaO 1.53%; Na2O 2.55%; K2O 0.61%; H2O+4.30%;
H2O7.9%; Cr2O3 0.0044%; ZnO 0.028%; NiO 0.0037%;
Li2O 0.003 8%; TiO2 0.24%; P2O5 0.034%; Mn0.016%;
Buring0.41%; Total 99.30%.
Figure 1. Sketch of four basic GCLs products.
er GT stitch fibe
er GT men
er GT
lower GT
lower GT lower GT
lower GT
256 X. B. Xiong et al. / J. Biomedical Science and Engineering 2 (2009) 254-260
SciRes Copyright © 2009 JBiSE
Figure 2. Section of composite liner. Figure 3. Section of the cap of landfill.
The swell stresses of a GCL, made by the CETCO
Company, USA, were measured directly using a custom-
made swell stress instrument under water-sorbed satura-
tion conditions. The results show that in the test process,
the variation of the swell stress curve with time can be
divided into three segments. To characterize the minera-
logical nature of the Nabentonite, six samples were
studied by X-ray diffraction and results show a relatively
homogeneous mineralogical composition. It consists of a
complex mixture of different smectites, those of sodium
nature clearly prevailing, with trace amounts of quartz,
calcite and muscovite. This is determined by the fact that
all the heated specimens collapse their main 001 spacing
to 10 A ˚ and expand that same spacing to 16.5~16.8 A˚
upon treatment.
By comparison of the seepage coefficient curve of the
two experimental conditions (see Figure 4), the seepage
coefficient are approximate same when the vertical
stress is less than 250kPa, otherwise, when the vertical
stress is more than 250kPa, the seepage coefficient by
Figure 4. Seepage coefficient test apparatus.
Table 2. The results of hydrated swelling experiments of GCLs
samples by main pressures. (Notes: MGCL is mass per unit
area of GCLs.)
σw/kPa MGCL/kg/m2H0/mm Hσ/mm Hw/mm w/%EB
3 5.39 6.84 6.72 9.67 131.33.38
15 5.37 6.87 6.52 8.61 112.62.91
50 5.48 6.85 6.27 7.70 102.12.44
150 5.33 6.87 5.86 6.52 92.41.98
300 5.45 6.85 5.46 5.85 70.11.72
400 5.44 6.87 5.37 5.69 63.21.65
experiments under conditions of hydrate firstly and
compress secondly (cw1) is lower than the seepage coef-
ficient by experiments under conditions of compress
firstly and hydrate secondly (wc2). That is, when the
vertical stress is more than 250kPa, and the experiments
under conditions of hydrate firstly and compress sec-
ondly, the thickness of GCLs is bigger, so that the seep-
age coefficient increase very slow.
The results of hydrated swelling experiments of GCLs
samples by main stress list in Table 2, through the data
of Table 2, firstly, the swelling deformation of GCLs
increase very fast because of the properties of water ab-
sorption of bentonite, till the thickness of GCLs without
change on the end. Under the series main stress such as
3kPa, 15kPa, 50kPa, 150kPa, 300kPa and 400kPa, the
hydrated time list sequences as 12.8d, 9.8d, 8.3d, 6.0d,
5.0d and 5.0d (see Figure 5). When at a low main
stress, the initial creep velocity is very high, and the
total hydrated thickness is big, with increasing of σw,
the thickness of GCLs decreasing, at the same time,
the water content(w) and porosity ratio decreasing
(show in Table 2).
From Table 3, we can find that the vertical pressure
take much effect on the seepage properties, the seep-
age coefficient increases along with the increasing of
the horizontal strain of GCLs, and when the horizontal
strain is more than 6.0%, the velocity of the seepage
coefficient increasing obviously. That is because,
when the GCLs was taken horizontal tense, not only
G. G. Adams et al. / J. Biomedical Science and Engineering 2 (2009) 254-260 257
SciRes Copyright © 2009 JBiSE
050100 150200250 300 350400 450
Vertical pressure(kPa)
Seepage cofficent
Figure 5. Seepage coefficient of GCLs under several conditions.
Table 3. Seepage coefficients by all grades Vertical pressure
of GCLs under the condition of compress firstly and hydrated
secondly or hydrate firstly and compress secondly.
seepage coefficient
seepage coefficient
(kPa) Compress
(kPa) Compress
25 25.6 37.3 250 0.738 0.840
50 20.6 20.6 300 0.916 0.407
100 18.9 13.1 350 1.40 0.463
200 2.32 3.78 400 1.43 0.581
the upper and the low GT cause horizontal extension,
and the bentonite stitched in the middle could be scat-
tered by horizontal tension, at the same time, the po-
rosity of the bentonite increases after water hydrated,
then the seepage coefficient increases. When the hori-
zontal strain is big (usually more than 6.0%), even
when the horizontal strain attain to 16.0%, the ben-
tonite grains decreasing, the thickness of some parts of
the GCLs is very low, the seepage properties is very
high, and the anti-seepage properties of GCLs vanish
wholly. From the above statement, in practical anti-
seepage engineering projects, the non-uniform settle-
ment of should be calculated before construction, and
the horizontal strain of GCLs is extremely controlled
to 6.0%, thus, the anti-seepage properties of GCLs
could be run ordinary.
In a newly built landfill facility, the lower most
leachate barrier is composed of GCL strips; adjoining
strips are not seamed and, instead, they partially overlap
and are ‘‘sealed’’ by a layer of sodium bentonite powder.
The performance of this Na-bentonite is the main object
of investigation of the present study. In laboratory re-
constructions, the mechanical and geotechnical behavior
of the Na-bentonite placed in between adjoining GCL
strips was evaluated, as it is in this situation that the
Na-bentonite is less constrained physically and thus
more prone to deformation and rupture. X-ray diffrac-
tometry was used to identify the minerals making up the
clay powder; several laboratory tests were performed to
geotechnically characterize the clay; and cakes with dif-
ferent water contents of sodium bentonite were submit-
ted to pure shear deformation using an automated pure
shear rig to evaluate its behavior when subject to load,
and wetting and drying cycles. The results prompted the
search for field evidence of clay rupture around the
landfill facility by means of geophysical and geochemi-
cal investigations, together with a detailed structural
study of the fracture network of the granite. The swelling
behavior of the Na bentonite is highly dependent on the
type of encapsulation between the cover and the carrier
geotextiles and on the chemical composition of the fluids
From the above, a reliable, easily handled and cheap
waterproof roll liner material was designed, in which the
Bentonite, a kind of clay soil with unusual self-sealing
ability, was used as the protective barrier for contain-
ment of hazardous waste in landfills. On the basis of the
materials’ choice, the permeability properties of this
new-style synthetic liner under various conditions were
tested. The permeability coefficient of Na+-Bentonite
was less than that of Ca2+-Bentonite. The suitable adhe-
sives can enhance the waterproof of Na+-Bentonite. Af-
ter Na+-Bentonite and the new liner were pretreated by
water and well maintained, they hardly changed their
permeability when they met such leachates as inorganic
acids/bases and organic solvent . The new liner presents
good “welding” property even if it was damaged. The
experimental results indicate that this kind of bentonite
waterproof roll liner is very suitable for landfill.
When MSWL was taken as the hydrated liquid and
seepage liquid, to analyze the chemical component of
the liquid seeping from GCLs, and attain all kinds of
single-species cation iron and Chemical Content of
BOD5, COD and NH4-N of Leachate from landfills,
from the data of Table 4, we can find that GCLs took
effective absorption with all kinds of single-species
cation iron and Chemical Content of BOD5, COD and
NH4-N. The results show that GCLs has large absorption
ability on the permeation liquids. But the ability is de-
creasing with increase of permeation volume, and the
types of hydration liquids exercise great influence on the
variation of GCLs absorption, and the content some sin-
gle-species cation iron of the permeation liquids has no
change, it shows that the absorption of GCls to cation
iron is very low.
Table 4. Chemical Content of BOD5, COD and NH4-N of
Leachate from landfills.
Flow of Porosity VolumeBOD5/mg/l COD/mg/l NH4-N/mg/l
0.50 800 6200 1059
1.25 900 6800 1538
2.09 1600 15800 1585
Original liquid 2500 16000 3426
258 X. B. Xiong et al. / J. Biomedical Science and Engineering 2 (2009) 254-260
SciRes Copyright © 2009 JBiSE
A series of confined swell tests were conducted on a
needle-punched GCLs with tap water as the hydration
medium. The effects of the static confining stress on the
swelling characteristics of GCLs and the hydration time
under different confining stresses were explored. In-
creasing the static confining stress led to: shorter hydra-
tion time; smaller final GCL height; less final GCL bulk
void ratio; smaller final bentonite moisture content.
4.1. Problem Statement
This calculator computes the rate of leakage through
defects in a composite liner, i.e. GCLs (see Figure 6).
The thickness of a hydrated GCLs depends on the com-
pressive stress applied during hydration. Typical values
are between 5 and 10 mm. Field evaluation, sponsered
by USEPA, of leakage rate for double-lined landfills
indicates that GM/GCL composite liners outperform
GM/ CCL liners (Othman et al., 1998.)
The rate of leakage through a GCL due to GCL per-
meability is negligible compared to the rate of leakage
through defects in the GCL Hence, only leakage through
defects will be considered. If there is a defect in the GCL,
the liquid first passes through the defect, then it flows
laterally some distance between the GCL and the
low-permeability soil, and, finally it infiltrates in the low
permeability soil.
Flow between GCL and low-permeability soil is
called interface flow, and is highly dependent upon the
quality of contact between the two components Contact
conditions are defined as follows:
1) Good contact conditions correspond to a GCL in-
stalled, with as few wrinkles as possible, on top of a
low-permeability soil layer that has been adequately
compacted and has a smooth surface. Contact quality
factor (Cqo) (circular, square, rectangular) is 0.21, Con-
tact quality factor (Cq) (infinite length) is 0.52.
* Space exaggerated to show interface flow
Figure 6. Schematic diagram of GM/GCL calculation section.
Table 5. Representative installation defect densities.
Installation qualityDefect density
(number per acre) Frequency
Excellent Up to 1 10
Good 1 to 4 40
Fair 4 to 10 40
Poor 10 to 20* 10
2) Poor contact conditions correspond to a GCL that
has been installed with a certain number of wrinkles,
and/or placed on a low-permeability soil that has not
been well compacted and does not appear smooth. Con-
tact quality factor (Cqo) (circular, square, rectangular) is
1.15, Contact quality factor (Cq) (infinite length) is
*Higher defect densities have been reported for older
landfills with poor installation operations and materials;
however, these high densities are not characteristic of
modern practice.
The Help model provides guidance for estimating the
defect densities. Some useful information on the Help
model is given in the Technical Note on Using HELP
Model (ver 3.07). There are mainly two types of defects,
manufacturing defects and installation defects. Typical
geomembranes may have about 0.5 to 1 (1 to 2 per hec-
tare) pinholes per acre from manufacturing defects
(Pinholes are defects with a diameter equal or smaller
than the geomembrane thickness. The density of instal-
lation defects is a function of the quality of installation,
testing, materials, surface preparation, equipment, and
QA/QC program. Representative installation defect den-
sities as a function of the quality of installation are given
in Table 5 for landfills being built today with the state of
the art in materials, equipment and QA/QC.
Studies by Giroud and Bonaparte have shown that for
geomembrane liners installed, with strict construction
quality assurance, could have one to two defects per acre
(4000m2) with a typical defect diameter of 2mm (i.e., a
defect area of 3.14×10-6 m
2). Typical for liner perform-
ance evaluation one defect per acre (4000m2) is consid-
ered with a defect area of 0.1 cm2 (equivalent to defect
diameter of 3.5 mm), for a conservative design a defect
area of 1 cm2 (equivalent defect diameter of 11 mm) can
be considered.
4.2. Problem Solution
Different geomembrane defect shapes will be consid-
ered: Circular defect with diameter of d ])/(1.01[976.0 Ssqo khdthCn
Rectangular defect with width of b and length of B:
G. G. Adams et al. / J. Biomedical Science and Engineering 2 (2009) 254-260 259
SciRes Copyright © 2009 JBiSE
Q-Leakage rate through the considered geomembrane
defect (m3/s);
Q*-Leakage rate per unit length of geomembrane de-
fect (m3/s.m);
A-Considered geomembrane area (m2);
N-Number of defects per considered geomembrane
area (A);
Co or Cq -Contact quality factor (see Table 6);
H-Hydraulic head on top of the geomembrane (m);
ts-Thickness of the low-permeability soil component
of the composite liner (m);
D-Diameter of circular defect (m);
b-Width of defect (m);
B-Length of rectangular defect (m).
Limitation of the equations presented:
1) If the effect is circular, the defect diameter should
be no less than 0.5 mm and not greater than 25 mm. In
the case of the defects that are not circular, it is proposed
to use these limitations for the defect width.
2) The liquid head on top of the geomembrane should
be equal to or less than 3 m.
4.3. Input Values
Case 1: Geometry of circular defect
Considered geomembrane area(A) is 4000m2;
Hydraulic head on top of the geomembrane(m) is 0.3m;
Thickness of the low-permeability soil(m) is 2m;
Permeability of the low-permeability soil(m/s) is
Properties of circular defect
Contact (good or poor) Good;Number of de-
fects (n) is 1; Diameter of defect (d) is 0.0002m.
Case 2: Geometry of Rectangular Defect
Properties of Rectangular Defect
Width of defect (b) is 0.002m; Length of defect (B) is
0.01m, the else conditions like Case 1.
In this paper, a series of research work including about
the laboratory tests of GCLs is conducted and several
valuable conclusions are obtained:
Table 6. Comparison between theoretical
number Theoretical
structure Practical anti- seep-
age structure
flow, m3/
One layer GM,
eneath high
seepage layer
GM+ foundation with
high permeability in-
dex or geocomposite
(such as geotextile)
One layer GM,
eneath low
seepage sub-
stituted layer
with low permeability
index (such as GCL)
1) A geosynthetic hydraulic conductivity device is de-
signed to measure seepage coefficients of GCLs under
constant normal stress conditions. Seepage coefficients
of GCLs is measured for different hydrated and perme-
ated liquids using the apparatus. Free swelling tests and
hydration swelling tests of GCLs and bentonnite per-
formed in order to research the swelling characteristics
of GCLs and its influencing factors, including normal
stress, loading-hydration sequence and hydration liquid.
The results show that these factors have influences on
GCLs swelling characteristics. Similar influencing laws
can be obtained in the two tests.
2) Seepage coefficients tests are performed to obtain
hydraulic conductivity of GCLs, taking liquids such as
distilled, deioned water and landfill leachate, and solu-
tions with single-species cation as the hydration and
permeation liquid, the results show that cation valence,
cation concentration and hydration ionic radius in hydra-
tion and permeation liquids have influences on hydraulic
conductivity of GCLs. The influences of stress condi-
tions and loading-hydration sequence on GCLs hydraulic
conductivity are researched, the results Show that nor-
mal stress and horizontal strain, as well as load-
ing-hydration sequence, all have influences on the vari-
ety of hydraulic conductivity.
3) Absorption ability of GCLs in the course of liquid
permeation is studied, and its influencing factors are also
discussed, including hydration liquid and permeation
time. The results show that GCLs has large absorption
ability on the permeation liquids. But the ability is de-
creasing with increase of permeation volume, and the
types of hydration liquids exercise great influence on the
variation of GCLs absorption.
4) Analysis are made to combine the conclusion ob-
tained in this study with practical engineering projects,
and proposals of building method of GCLs are ad-
Some research results described in this paper were de-
veloped by the author in his graduate study between
1997 and 2000 in Nanjing University. The author grate-
fully acknowledges his teacher (Academician of Chinese
Academy of Sciences Prof. Jun SUN) for his helpful
direction and suggestion to the author during his study-
ing in Tongji University. The authors would like to ex-
press their thanks to many teachers and staffs at the uni-
versity of tongji university, nanjing university, and china
university of geosciences, and jinggangshan university
for the help in presenting some related experimental
[1] J. Sun, et al., (2005) Municipal environmental geotech-
nical engineering [M]. Shanghai: Shanghai Scientific and
260 X. B. Xiong et al. / J. Biomedical Science and Engineering 2 (2009) 254-260
SciRes Copyright © 2009 JBiSE
Technical Publishers. (In Chinese).
[2] X. B. Xiong, (2000) Environmental geotechnical re-
search on municipal sanitary landfill, Nanjing: Nanjing
[3] B. Shi, et al., (2003) Environmental geotechnical prob-
lems and their treatment of municipal sanitary landfills in
the southeast of China, Journal of Disaster prevention
and Mitigation Engineering, 23(4), 91-97.
[4] H. Y. Fang, (2000) Environmental geotechnology per-
spective in the 21st century, Chinese Journal of Geotech-
nical Engineering, 22(1), 1-11.
[5] Z. B. Li, (2007) Research on anti-seepage availability of
geosynthetic clay liners and related mechanism analysis,
Shanghai: Tongji University.
[6] J. He, C. H. Xia, and J. S. Hu, (2007) Equivalence analy-
sis of GCL and CCL composite liner, Hydrogeology &
Engineering Geology, 3, 102-106.
[7] X. B. Xiong, B. Shi, et al., (2000) The recent develop-
ment of geotechnical research on municipal waste sani-
tary landfill in foreign countries, Journal of Engineering
Geology, 3, 345-350.
[8] X. B. Xiong, B. Shi, et al. (2000) Current status and
prospects of geotechnical research on the municipal solid
Waste (MSW) disposal in China”, Hydrogeology and
Engineering geology, 3, 25-29.
[9] X. B. Xiong, B. Shi, and W. He, (2000) The current de-
velopment of geotechnical research on municipal sani-
tary landfill in China, Proceedings of the International
Symposium on High Altitude & Sensitive Ecological
Environmental Geotechnology, “Environmental Geo-
technology,” Nanjing University Press, 76-85.
[10] X. B. Xiong, G. Q. Gui, B. Shi, et al., (2008) Evaluation
and discussion of liner system in sanitary landfills, Pro-
ceedings of the 9th International Symposium on Envi-
ronmental Geotechnology and Global Sustainable De-
velopment, Hong Kong University.
[11] M. Y. Horace, et al., (2004) Characterization of infiltration
rates from landfills supporting groundwater modeling ef-
forts, Environmental Monitoring and Assessment, Springer
Netherlands, ISSN 0167-6369 (Print) 1573-2959 (Online),
96(1-3), 283-311.
[12] A. Bouazza, (2002) Review article: Geosynthetic clay
liners, Geotextiles and Geomembranes, 20, 3-17.
[13] G. R. J. Browning, (1998) Geosynthetic clay liners: A
review and evaluation, Trans. Inst. Min. Metall., Sect. B,
107, 120-129.
[14] R. M. Koerner, (1994) Geosynthetic clay liners, Chapter
6, Designing with Geosynthetics, 3rd Edition, Prentice-
Hall, Englewood Cliffs, N. J., 624-657.
[15] G. Heerten, (2002) Geosynthetic clay liner performance
in geotechnical applications, In: Koerner and Gartung
(Eds.), Clay geosynthetic barriers, 3-19.
[16] J. M. Southen and R. K. Rowe, (2005) Modeling of ther-
mally induced desiccation of geosynthetic clay liners,
Geotextiles and Geomembranes, 23, 425-442.