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Production and use of geotextiles in Poland
Geotextiles and Geomembranes 4 (1986) 9-19
Production and Use of Geotextiles in Poland Eugeniusz Dembicki Hydraulic Institute, Gdafisk TechnicalUniversity, Gdafiskul. Majakowskiego 11, Poland and H e n r y k Sieczka Civil Engineering Institute, BiafystokTechnical University, Bia~ystokul. Wiejska 45a, Poland
ABSTRACT Characteristics of" synthetic fibres used for producing geotextiles have been studied and it was found that polypropylene and polyester fibres had the best properties. The different stages of the production process are described together with the different types of Polish products. Tests performed on these geotextiles to measure their identification, chemical, biological and hydraulic basic properties are described and test data Jbr Polish geotextiles are given. In conclusion briefcase histories present uses of geotextiles in road and hydraulic engineering projects.
1. G E O T E X T I L E S P R O D U C E D IN P O L A N D N o n - w o v e n geotextiles are fiat textile products made of a b o n d e d layer of fibres. Synthetic fibres used for producing Polish geotextiles are generally polyester, polypropylene, polyamide, and refuse from production of these fibres. The best properties are obtained from polyester which has been p r o d u c e d in Poland on a commercial scale since 1960 under licence. This polyester, marketed under the trade name Elana, is characterised by good tensile strength in the dry and in the wet (approximately 40 cN/ tex* = 520 MPa for polyester with p = 1300 kg/m3; 67 cN/tex = 600 MPa for polypropylene with p = 900 kg/m3), a good abrasion resistance * The tex is a measure of linear fibre density and is in units of 10-6kg/m. 9 Geotextiles and Geomembranes 0266-1144/86/$03.50 O Elsevier Applied Science Publishers Ltd, England. 1986. Printed in Great Britain
10
Eugeniusz Dembicki, Henryk Sieczka
and a low extensibility (15% approximately), which is an advantage where excessive deformation is to be avoided. Geotextile fibres showing the best resistance to chemical and biological agents and to sunlight are polyester and polypropylene. In spite of their good tensile strength, up to 67 cN/tex, polypropylenes have a fairly low abrasion resistance and do not behave well at high temperatures. Polyamide production started in Gorzow Wielkopolski in the 'fifties. This polymer is also characterised by good tensile strength, up to 85 cN/tex, as well as good torsion and fatigue strengths. A specific feature of polyamide fibres is their high abrasion resistance. However they do have the defect of being very sensitive to sunlight, i.e. UV attack, and have a low resistance to chemical agents. The production process includes two fundamental states which are common in the production of nonwovens. The first is to produce a mat, the second to reinforce, or consolidate, the mat. For geotextiles produced in Poland the fibre mat is either laid mechanically using carding brushes or it is air laid. The loose mat is stabilised mechanically by needle-punching. In production of the mechanically laid mat use is made of carding brushes similar to those used in the production of other textiles. The cards are operated to control the texture of the mat and its mass per unit area. With air-laid mat production there is little contact between successive layers and this can give rise to low tensile strength. The loose mats are consolidated and strengthened by needle-punching. Under the effect of the barbs of the needles, needle-punching displaces the fibres in the direction perpendicular to the plane of the mat and, in this way, makes a link between the successive layers produced in the matforming process. Therefore the strength of the product is improved and its density is increased. The basic parameters in the needle-punching process are the number of needle holes per cm z and the depth of punching. The number of holes determines the density and the properties of the geotextile. It should be noted that the tear resistance increases with the number of needle holes per unit area, up to a limiting value. Beyond this value, a weakening of the product is observed, due to a shortening of connecting fibres. Mat reinforcement may also be obtained by stitching with thread orstaple fibres. Stitching is carried out using sewing machines such as Arachne, Arabeva, Maliwatt, Malirbies or WP-180, equipped with multiple-needle systems. The first geotextile production tests, essentially for road construction, were conducted in 1974 in the Central Textile Products Laboratory in
Production and use of geotextiles in Poland
11
Lodz. Reduced scale production of the first geotextiles WD-EB and WD-2 were undertaken at the Felt Industry Establishment in Lodz. The technology to produce the geotextile WD-3 for hydraulic engineering applications has also been developed, based on the experience of the Danish Company Fibertex. Full-scale production has not yet been started. The geotextile WD-EB for road works (commercial reference I/S,, 5715) comprises 50% refuse fibre, 30% Polish polyester fibre (Bistor '~) and 20% Elana. Production is by carding and needle-punching. The geotextile WD-2 for road works (commercial reference I / S i n - 5106) comprises 50% polypropylene and 50% Elana and is again 16roduced by carding and needle-punching. Geotextile WD-3 comprises 50% polypropylene and 50% polyester and is bonded by needle-punching followed by polymer impregnation. These products have been tested at the Technical Textile Products Research Centre (COBRTWW) in Lodz to assess their durability and resistance to non-organic and organic chemicals attack and at the Organic Industry Institute in Warsaw to assess resistance to microbiological attack by fungi and bacteria. Depending on the results of the research programme on properties, being conducted at the Road Research Institute in Warsaw, the geotextiles may be used in road engineering. Geotextile WD-EB is only recommended for construction of temporary roads with a maximum of three years' design life, whilst WD-2 may be used for construction of permanent roads. The Felt Industry Establishment in Lodz has recently started production of a new needle-punched geotextile for road works (commercial reference I/Sin - 5716) made from 50% 6.7 dtex polypropylene fibres and 50% synthetic refuse. In the Chemical Fibres Establishment Chemitex-Elana in Torun, the refuse from the production of polyester fibres is recycled for producing a geotextile. The mat is made with the mechanical method on a Befama carding machine and reinforced by stitching on Malimo machines.
2. TESTS OF QUALITY AND TECHNICAL PROPERTIES OF GEOTEXTILES In different Polish centres, research has been undertaken to investigate the possibility of using nationally produced geotextiles for various civil
12
Eugeniusz Dembicki, Henryk Sieczka
engineering applications. Tests have been carried out to determine identification characteristics, mechanical, chemical, biological and hydraulic properties, so allowing an assessment of the suitability of the various geotextiles for different types of work. Identification characteristics do not give any direct indication of geotextile suitability for a particular application. However these characteristic values such as mass per unit .area and thickness govern the nature of the geotextile and its mechanical and hydraulic properties. The mass per unit area is obtained by weighing a 1 m 2geotextile sample and is expressed in grams per m-'. Sampling, conditioning of samples, measurement and presentation of results are carried out according to Polish standard PN-75/P-04613. Thickness of a fiat textile product corresponds to the distance between two parallel planes in contact under a given pressure. Thickness variation under the effect of loading has a definite influence on hydraulic properties of geotextiles, particularly on permeability. Accordingly, sample analysis has to be made both dry and wet. Determination of mechanical properties is made for all geotextiles irrespective of their end use. One of the easiest tests to perform, and consequently one of the most frequently used, is the simple uni-axial tensile test, with measurement of extension at failure. This test is carried out in accordance with Polish standard PN-74/P-04626. Resistance to punching is determined as the force necessary to drive a metal sphere of a given diameter through the geotextile. Testing is in accordance with Polish standard PN-72/P-04738. This test allows an assessment of the resistance of the geotextiles to perforation as might be caused by the placing of rip rap or similar rock fill. Chemical and biological resistance of geotextiles is directly related to the behaviour of the polymers used to produce them. C O B R T W W has undertaken the testing of geotextiles with respect to their ability to be dissolved in inorganic acids and alkalis, organic acids and organic solvents. The influence of these chemicals on different polymers is summarised in Tables 1 and 2. Assessment of biological properties of geotextiles includes: (1) tests according to standard PN-63/P-04730, to determine if the product may be a nutrient for top-soil microflora (fungi and bacteria) and so become the location of fungi development. (2) tests according to standard PN-73/P-04731, to determine the tensile strength of the geotextile before and after burial in a top-soil
13
Production and use of geotextiles in Poland TABLE 1
Fibre Solubilityin Acids and Alkalis Sulphuric Hydrochloric acid acid (96%) (36%)
Temperature during testing
Nitric acid (62%)
20
100
20
20
+ + .
+ +
.
P -
Acetic Formic Sodium acid acid hydroxide (100%) (90%) (5%)
100 20 100 20 100 20 100
(of) Fibres: Polyamide Polyester Polypropylene
.
.
+
-
p -
p -
+, Fibre is dissolved - , Fibre does not dissolve. P, Fibre does not dissolve but loses its shape and is plasticised. of given composition and biological activity, for periods of 14 and 28 days. Before selecting a geotextile for a given use, it is important to determine the properties that have been listed above, but it should be also noted that p a r a m e t e r s dealing with hydraulic properties are important if the geotextile is to be used as a filter material. In the case of geotextiles in which pores are hardly visible and difficult to measure, a sieving technique is used to determine the pore size. By filtration of soil particles, dispersed in water, it is possible to measure the d i a m e t e r of soil particles passing through the geotextile and the diameter of particles retained by it. The interval between these two diameters is an approximate m e a s u r e m e n t of the geotextile pore size. Comparing these figures and the properties of the soil gives an evaluation of the ability of the geotextile to protect the soil against erosion. Hydraulic properties of geotextiles are characterised by the water permeability coefficient K, which may be determined with a device such as the ITB-ZWK2, according to the standard PN-55/B-04492. For nationally m a d e geotextiles, the value of K is generally about 10 -4 m / s , for a flow perpendicular to the plane of the fabric. Table 3 gives results for some Polish-made geotextiles, their fundamental technical parameters being taken from the literature. 1-4
20
J
20
Methylene chloride
For explanation of symbols, see Table 1 footnote.
Fibres: Polyamide Polyester Polypropylene
Temperature of solvent d u r i n g t e s t i n g (°C)
Acetone
20
Benzene
--
_
p
p _
-
-
20
--
85
__
p
+
90
Trichloroethylene Phenol C2HCI3
TABLE 2 Fibre Solubility in O r g a n i c S o l v e n t s
-
__
-
--
20
_
p
_
__
100
Xylene
_
--
_
__
20
p
100
Toluene
~
/'4
~
r~
7.
mm
N/m N/m
% length % length
2. Thickness
3. Tensile strength Warp Weft
4o Tear resistance Warp Weft
m/s
g/m 2
1. Mass per unit area
5. Normal permeability coefficient
Units
Parameter
--
120 130
45 171
3
150
Geotextile
128 80
161 443
4
200
Geotextile
6-6 x 10 -3
140 75
186 659
5
300
Geotextile
2 x 10 -5
115 136
275 545
4
500
WD-EB
155 87
307 718
4
400
WD-2
1.5 x 10 -4
Geotextile grade
TABLE 3 Technical Characteristics of Polish GeotextUes
8-4 × 10 -3
150 92
377 757
5
300
WD-3
9-7 x 10 -3
141 93
465 668
5
600
Geotextile
E"
N"
ga.
16
Eugeniusz Dembicki, Henryk Sieczka
3. E X A M P L E S OF USE OF POLISH GEOTEXTILES The polyester fabric trade name 'Geotextile', available in 150,200, 300 and 600 g/m z grades, was used for reinforcing the subgrade of agricultural roads and as part o f the revetment protection to embankments on the River Notec (Fig. 1). 2To allow construction of the agricultural roads, the subgrade was prepared by removal of all roots and vegetation, followed by infilling of any surface depressions using local soil. Two rolls of 2.4 m wide 300 g/m 2geotextile were laid down side-by-side with a central overlay of 0.5 m so covering a 4.3 m wide formation width, Fig. t. The geotextile was then covered with a 350 mm layer of sand and covered with lOMB 5
3
L
4)0m j
IF~. 1. Cross-section of flood embankment and country road. 1: peat, 2: gynla, 3: sand, 4: concrete-plates, 5: geote×tile.
precast concrete slabs which serve as a running surface. Measurement of deflection profiles indicate very little movement and there is no sign of punching of the siabs under traffic load. Adjacent to the agricultural roads dykes were constructed to protect the low-lying agricultural land. Due to the long haul distance involved in importing granular fill the dykes were constructed using locally available peat capped with sand fill. On the upstream side of the dyke, which is some 3 km long, use was made of 150,200 and 300 g/m 2grade geotextile. These were unrolled on the prepared slope, with a 200 mm overlap, and held in position with wooden pegs. The surface of the geotextile was protected with a 100 mm thick layer of f~esh peat which was seeded with a mixture of grasses. This project involved the use of some 38 000 m s of geotextile. Upstream slopes of the Draty balancing reservoir have been protected using open concrete blocks placed on acrylic fabrics and WD-EB, Fig. 2. The total area covered in this manner was 28 000 m z. Downstream slopes
Production and use of geotextiles in Poland
1
2
17
3
Fig. 2. Protection against the embankment erosion. 1: concrete plates, 2: geotextile, 3: sand bed. 2
l_]
0,30m
~]
1
3
g~
E
~ o,zo.J Fig. 3. Main drainage of earth dam. 1: geotextile, 2: sand--gravel mix, 3: sand bed.
of the reservoir have been drained using slotted PVC pipe, 100 mrn in diameter. PVC drain pipes have been covered over their flail length with an acrylic geotextile and placed on a sand fill 0.10 m thick. The total length of the drainage system is 4 km. Geotextiles have also been used for constructing the filter to the drainage system of the storage reservoir at Jeziorsko on the Wanta ~iver (Fig. 3). On this project 'Terratex' was used with one short experimental length being built using the Polish geotextile WD-3. In total some 15 000 m 2 of geotextile were used on this project. Good results have been obtained in using geotextiles in temporary roads and storage areas. 1In temporary road construction, the geotextile is laid directly on the levelled subgrade. It is then covered by a fill material
Eugeniusz DembickL Hen~k Sieczka
18
3
. . . . . .
""
"
"'
"
"
*
'
'1"
b.
~:i
"
"
'i
''
.
.
.
.
''
"
" 1 '
"1'
"
"
"
5
4
L:: i . : . :. :: :: ! : ' : :": :.:: i: ~: .;L: :i~ : :i: : :
Fig. 4. Cross-sections of temporary roads. 1: embankment, 2: geotextile, 3: concreteplates, 4: wearing course, 5: stabilised foundation. '7,60 m
9,60 m
ii
0,35 I~_
m
-7
1
/
Fill. 5. Cross-section of railway subgrade. 1: ballast, 2: geotextile, 3: filter layer. which in turn is covered by precast slabs so forming the road pavement. In s o m e cases the concrete slabs are replaced by a cement or fly-ash stabilised layer (Fig. 4). Geotextiles m a y also be used in the construction of railways (Fig. 5). In this case, they are installed as a protective layer beneath the track ballast and their function is to reduce the stresses on the subgrade soil, to drain w a t e r and to prevent the ballast mixing with the subgrade soil.
4. C O N C L U S I O N S A t the present time, the Polish market offers a road geotextile under the c o m m e r c i a l reference (Sin - 5716) produced by the Felt Industry
Production and use of geotextiles in Poland
19
Establishment in Lodz, and a polyester geotextile 'Geowloknina' produced by the Chemical Fibres Establishment Chemitex-Elana in Torun. The properties of these geotextiles indicate their use as filtration and reinforcement materials. For geotextiles used in earth structures it is useful to complement the study of their basic characteristics by the observation of their in-situ behaviour over a period of several years, to assess their performance under natural conditions.
REFERENCES 1. Jaworski, J., Dzierzawski, K. and Machczynski, W., Report on definition of selection criteria for fill materials in temporary road construction using geotextiles [in Polish], Research Institute of the Road Administration, Warsaw (1978). 2. Sender, K., Reinforcement of agricultural roads and of unsubmersible dikes slopes with a recycled polyester fiber geotextile [in Polish], VI National Conference on Soil Mechanics and Foundation Engineering, Warsaw (1981).
3. Sokolowski, J., Krzywosz, Z. and Jedryka, G., Methods for Quality Control and Technical Characteristics Measurement of Filter Geotextiles [In Polish], SGGW-AR, Warsaw (1980). 4. Szatkowski, Z., Geotextile Technology [in Polish], WNT, Warsaw (1971).
Production and Use of Geotextiles in Poland Eugeniusz Dembicki Hydraulic Institute, Gdafisk TechnicalUniversity, Gdafiskul. Majakowskiego 11, Poland and H e n r y k Sieczka Civil Engineering Institute, BiafystokTechnical University, Bia~ystokul. Wiejska 45a, Poland
ABSTRACT Characteristics of" synthetic fibres used for producing geotextiles have been studied and it was found that polypropylene and polyester fibres had the best properties. The different stages of the production process are described together with the different types of Polish products. Tests performed on these geotextiles to measure their identification, chemical, biological and hydraulic basic properties are described and test data Jbr Polish geotextiles are given. In conclusion briefcase histories present uses of geotextiles in road and hydraulic engineering projects.
1. G E O T E X T I L E S P R O D U C E D IN P O L A N D N o n - w o v e n geotextiles are fiat textile products made of a b o n d e d layer of fibres. Synthetic fibres used for producing Polish geotextiles are generally polyester, polypropylene, polyamide, and refuse from production of these fibres. The best properties are obtained from polyester which has been p r o d u c e d in Poland on a commercial scale since 1960 under licence. This polyester, marketed under the trade name Elana, is characterised by good tensile strength in the dry and in the wet (approximately 40 cN/ tex* = 520 MPa for polyester with p = 1300 kg/m3; 67 cN/tex = 600 MPa for polypropylene with p = 900 kg/m3), a good abrasion resistance * The tex is a measure of linear fibre density and is in units of 10-6kg/m. 9 Geotextiles and Geomembranes 0266-1144/86/$03.50 O Elsevier Applied Science Publishers Ltd, England. 1986. Printed in Great Britain
10
Eugeniusz Dembicki, Henryk Sieczka
and a low extensibility (15% approximately), which is an advantage where excessive deformation is to be avoided. Geotextile fibres showing the best resistance to chemical and biological agents and to sunlight are polyester and polypropylene. In spite of their good tensile strength, up to 67 cN/tex, polypropylenes have a fairly low abrasion resistance and do not behave well at high temperatures. Polyamide production started in Gorzow Wielkopolski in the 'fifties. This polymer is also characterised by good tensile strength, up to 85 cN/tex, as well as good torsion and fatigue strengths. A specific feature of polyamide fibres is their high abrasion resistance. However they do have the defect of being very sensitive to sunlight, i.e. UV attack, and have a low resistance to chemical agents. The production process includes two fundamental states which are common in the production of nonwovens. The first is to produce a mat, the second to reinforce, or consolidate, the mat. For geotextiles produced in Poland the fibre mat is either laid mechanically using carding brushes or it is air laid. The loose mat is stabilised mechanically by needle-punching. In production of the mechanically laid mat use is made of carding brushes similar to those used in the production of other textiles. The cards are operated to control the texture of the mat and its mass per unit area. With air-laid mat production there is little contact between successive layers and this can give rise to low tensile strength. The loose mats are consolidated and strengthened by needle-punching. Under the effect of the barbs of the needles, needle-punching displaces the fibres in the direction perpendicular to the plane of the mat and, in this way, makes a link between the successive layers produced in the matforming process. Therefore the strength of the product is improved and its density is increased. The basic parameters in the needle-punching process are the number of needle holes per cm z and the depth of punching. The number of holes determines the density and the properties of the geotextile. It should be noted that the tear resistance increases with the number of needle holes per unit area, up to a limiting value. Beyond this value, a weakening of the product is observed, due to a shortening of connecting fibres. Mat reinforcement may also be obtained by stitching with thread orstaple fibres. Stitching is carried out using sewing machines such as Arachne, Arabeva, Maliwatt, Malirbies or WP-180, equipped with multiple-needle systems. The first geotextile production tests, essentially for road construction, were conducted in 1974 in the Central Textile Products Laboratory in
Production and use of geotextiles in Poland
11
Lodz. Reduced scale production of the first geotextiles WD-EB and WD-2 were undertaken at the Felt Industry Establishment in Lodz. The technology to produce the geotextile WD-3 for hydraulic engineering applications has also been developed, based on the experience of the Danish Company Fibertex. Full-scale production has not yet been started. The geotextile WD-EB for road works (commercial reference I/S,, 5715) comprises 50% refuse fibre, 30% Polish polyester fibre (Bistor '~) and 20% Elana. Production is by carding and needle-punching. The geotextile WD-2 for road works (commercial reference I / S i n - 5106) comprises 50% polypropylene and 50% Elana and is again 16roduced by carding and needle-punching. Geotextile WD-3 comprises 50% polypropylene and 50% polyester and is bonded by needle-punching followed by polymer impregnation. These products have been tested at the Technical Textile Products Research Centre (COBRTWW) in Lodz to assess their durability and resistance to non-organic and organic chemicals attack and at the Organic Industry Institute in Warsaw to assess resistance to microbiological attack by fungi and bacteria. Depending on the results of the research programme on properties, being conducted at the Road Research Institute in Warsaw, the geotextiles may be used in road engineering. Geotextile WD-EB is only recommended for construction of temporary roads with a maximum of three years' design life, whilst WD-2 may be used for construction of permanent roads. The Felt Industry Establishment in Lodz has recently started production of a new needle-punched geotextile for road works (commercial reference I/Sin - 5716) made from 50% 6.7 dtex polypropylene fibres and 50% synthetic refuse. In the Chemical Fibres Establishment Chemitex-Elana in Torun, the refuse from the production of polyester fibres is recycled for producing a geotextile. The mat is made with the mechanical method on a Befama carding machine and reinforced by stitching on Malimo machines.
2. TESTS OF QUALITY AND TECHNICAL PROPERTIES OF GEOTEXTILES In different Polish centres, research has been undertaken to investigate the possibility of using nationally produced geotextiles for various civil
12
Eugeniusz Dembicki, Henryk Sieczka
engineering applications. Tests have been carried out to determine identification characteristics, mechanical, chemical, biological and hydraulic properties, so allowing an assessment of the suitability of the various geotextiles for different types of work. Identification characteristics do not give any direct indication of geotextile suitability for a particular application. However these characteristic values such as mass per unit .area and thickness govern the nature of the geotextile and its mechanical and hydraulic properties. The mass per unit area is obtained by weighing a 1 m 2geotextile sample and is expressed in grams per m-'. Sampling, conditioning of samples, measurement and presentation of results are carried out according to Polish standard PN-75/P-04613. Thickness of a fiat textile product corresponds to the distance between two parallel planes in contact under a given pressure. Thickness variation under the effect of loading has a definite influence on hydraulic properties of geotextiles, particularly on permeability. Accordingly, sample analysis has to be made both dry and wet. Determination of mechanical properties is made for all geotextiles irrespective of their end use. One of the easiest tests to perform, and consequently one of the most frequently used, is the simple uni-axial tensile test, with measurement of extension at failure. This test is carried out in accordance with Polish standard PN-74/P-04626. Resistance to punching is determined as the force necessary to drive a metal sphere of a given diameter through the geotextile. Testing is in accordance with Polish standard PN-72/P-04738. This test allows an assessment of the resistance of the geotextiles to perforation as might be caused by the placing of rip rap or similar rock fill. Chemical and biological resistance of geotextiles is directly related to the behaviour of the polymers used to produce them. C O B R T W W has undertaken the testing of geotextiles with respect to their ability to be dissolved in inorganic acids and alkalis, organic acids and organic solvents. The influence of these chemicals on different polymers is summarised in Tables 1 and 2. Assessment of biological properties of geotextiles includes: (1) tests according to standard PN-63/P-04730, to determine if the product may be a nutrient for top-soil microflora (fungi and bacteria) and so become the location of fungi development. (2) tests according to standard PN-73/P-04731, to determine the tensile strength of the geotextile before and after burial in a top-soil
13
Production and use of geotextiles in Poland TABLE 1
Fibre Solubilityin Acids and Alkalis Sulphuric Hydrochloric acid acid (96%) (36%)
Temperature during testing
Nitric acid (62%)
20
100
20
20
+ + .
+ +
.
P -
Acetic Formic Sodium acid acid hydroxide (100%) (90%) (5%)
100 20 100 20 100 20 100
(of) Fibres: Polyamide Polyester Polypropylene
.
.
+
-
p -
p -
+, Fibre is dissolved - , Fibre does not dissolve. P, Fibre does not dissolve but loses its shape and is plasticised. of given composition and biological activity, for periods of 14 and 28 days. Before selecting a geotextile for a given use, it is important to determine the properties that have been listed above, but it should be also noted that p a r a m e t e r s dealing with hydraulic properties are important if the geotextile is to be used as a filter material. In the case of geotextiles in which pores are hardly visible and difficult to measure, a sieving technique is used to determine the pore size. By filtration of soil particles, dispersed in water, it is possible to measure the d i a m e t e r of soil particles passing through the geotextile and the diameter of particles retained by it. The interval between these two diameters is an approximate m e a s u r e m e n t of the geotextile pore size. Comparing these figures and the properties of the soil gives an evaluation of the ability of the geotextile to protect the soil against erosion. Hydraulic properties of geotextiles are characterised by the water permeability coefficient K, which may be determined with a device such as the ITB-ZWK2, according to the standard PN-55/B-04492. For nationally m a d e geotextiles, the value of K is generally about 10 -4 m / s , for a flow perpendicular to the plane of the fabric. Table 3 gives results for some Polish-made geotextiles, their fundamental technical parameters being taken from the literature. 1-4
20
J
20
Methylene chloride
For explanation of symbols, see Table 1 footnote.
Fibres: Polyamide Polyester Polypropylene
Temperature of solvent d u r i n g t e s t i n g (°C)
Acetone
20
Benzene
--
_
p
p _
-
-
20
--
85
__
p
+
90
Trichloroethylene Phenol C2HCI3
TABLE 2 Fibre Solubility in O r g a n i c S o l v e n t s
-
__
-
--
20
_
p
_
__
100
Xylene
_
--
_
__
20
p
100
Toluene
~
/'4
~
r~
7.
mm
N/m N/m
% length % length
2. Thickness
3. Tensile strength Warp Weft
4o Tear resistance Warp Weft
m/s
g/m 2
1. Mass per unit area
5. Normal permeability coefficient
Units
Parameter
--
120 130
45 171
3
150
Geotextile
128 80
161 443
4
200
Geotextile
6-6 x 10 -3
140 75
186 659
5
300
Geotextile
2 x 10 -5
115 136
275 545
4
500
WD-EB
155 87
307 718
4
400
WD-2
1.5 x 10 -4
Geotextile grade
TABLE 3 Technical Characteristics of Polish GeotextUes
8-4 × 10 -3
150 92
377 757
5
300
WD-3
9-7 x 10 -3
141 93
465 668
5
600
Geotextile
E"
N"
ga.
16
Eugeniusz Dembicki, Henryk Sieczka
3. E X A M P L E S OF USE OF POLISH GEOTEXTILES The polyester fabric trade name 'Geotextile', available in 150,200, 300 and 600 g/m z grades, was used for reinforcing the subgrade of agricultural roads and as part o f the revetment protection to embankments on the River Notec (Fig. 1). 2To allow construction of the agricultural roads, the subgrade was prepared by removal of all roots and vegetation, followed by infilling of any surface depressions using local soil. Two rolls of 2.4 m wide 300 g/m 2geotextile were laid down side-by-side with a central overlay of 0.5 m so covering a 4.3 m wide formation width, Fig. t. The geotextile was then covered with a 350 mm layer of sand and covered with lOMB 5
3
L
4)0m j
IF~. 1. Cross-section of flood embankment and country road. 1: peat, 2: gynla, 3: sand, 4: concrete-plates, 5: geote×tile.
precast concrete slabs which serve as a running surface. Measurement of deflection profiles indicate very little movement and there is no sign of punching of the siabs under traffic load. Adjacent to the agricultural roads dykes were constructed to protect the low-lying agricultural land. Due to the long haul distance involved in importing granular fill the dykes were constructed using locally available peat capped with sand fill. On the upstream side of the dyke, which is some 3 km long, use was made of 150,200 and 300 g/m 2grade geotextile. These were unrolled on the prepared slope, with a 200 mm overlap, and held in position with wooden pegs. The surface of the geotextile was protected with a 100 mm thick layer of f~esh peat which was seeded with a mixture of grasses. This project involved the use of some 38 000 m s of geotextile. Upstream slopes of the Draty balancing reservoir have been protected using open concrete blocks placed on acrylic fabrics and WD-EB, Fig. 2. The total area covered in this manner was 28 000 m z. Downstream slopes
Production and use of geotextiles in Poland
1
2
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3
Fig. 2. Protection against the embankment erosion. 1: concrete plates, 2: geotextile, 3: sand bed. 2
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1
3
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~ o,zo.J Fig. 3. Main drainage of earth dam. 1: geotextile, 2: sand--gravel mix, 3: sand bed.
of the reservoir have been drained using slotted PVC pipe, 100 mrn in diameter. PVC drain pipes have been covered over their flail length with an acrylic geotextile and placed on a sand fill 0.10 m thick. The total length of the drainage system is 4 km. Geotextiles have also been used for constructing the filter to the drainage system of the storage reservoir at Jeziorsko on the Wanta ~iver (Fig. 3). On this project 'Terratex' was used with one short experimental length being built using the Polish geotextile WD-3. In total some 15 000 m 2 of geotextile were used on this project. Good results have been obtained in using geotextiles in temporary roads and storage areas. 1In temporary road construction, the geotextile is laid directly on the levelled subgrade. It is then covered by a fill material
Eugeniusz DembickL Hen~k Sieczka
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Fig. 4. Cross-sections of temporary roads. 1: embankment, 2: geotextile, 3: concreteplates, 4: wearing course, 5: stabilised foundation. '7,60 m
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Fill. 5. Cross-section of railway subgrade. 1: ballast, 2: geotextile, 3: filter layer. which in turn is covered by precast slabs so forming the road pavement. In s o m e cases the concrete slabs are replaced by a cement or fly-ash stabilised layer (Fig. 4). Geotextiles m a y also be used in the construction of railways (Fig. 5). In this case, they are installed as a protective layer beneath the track ballast and their function is to reduce the stresses on the subgrade soil, to drain w a t e r and to prevent the ballast mixing with the subgrade soil.
4. C O N C L U S I O N S A t the present time, the Polish market offers a road geotextile under the c o m m e r c i a l reference (Sin - 5716) produced by the Felt Industry
Production and use of geotextiles in Poland
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Establishment in Lodz, and a polyester geotextile 'Geowloknina' produced by the Chemical Fibres Establishment Chemitex-Elana in Torun. The properties of these geotextiles indicate their use as filtration and reinforcement materials. For geotextiles used in earth structures it is useful to complement the study of their basic characteristics by the observation of their in-situ behaviour over a period of several years, to assess their performance under natural conditions.
REFERENCES 1. Jaworski, J., Dzierzawski, K. and Machczynski, W., Report on definition of selection criteria for fill materials in temporary road construction using geotextiles [in Polish], Research Institute of the Road Administration, Warsaw (1978). 2. Sender, K., Reinforcement of agricultural roads and of unsubmersible dikes slopes with a recycled polyester fiber geotextile [in Polish], VI National Conference on Soil Mechanics and Foundation Engineering, Warsaw (1981).
3. Sokolowski, J., Krzywosz, Z. and Jedryka, G., Methods for Quality Control and Technical Characteristics Measurement of Filter Geotextiles [In Polish], SGGW-AR, Warsaw (1980). 4. Szatkowski, Z., Geotextile Technology [in Polish], WNT, Warsaw (1971).