A METHOD FOR PRODUCING GEOCELLS AND GEOGRIDS USING ARECA
LEAF SHEATH
FIELD OF INVENTION
[0001] The embodiment herein generally relates to geogrids made of organic material. More specifically, the invention provides a method for producing geocells and geogrids using Areca leaf sheath that can be used for civil engineering applications.
BACKGROUND AND PRIOR ART
[0002] A geogrid is geosynthetic material used to reinforce soils and similar materials. Geogrids are commonly used to reinforce retaining walls, as well as sub-bases or sub-soils below roads or structures where soils pull apart under tension. Compared to soil, geogrids are strong in tension. This fact allows them to transfer forces to a larger area of soil than would otherwise be the case.
[0003] Generally, geogrids are made of polymer materials, such as polyester, polyvinyl alcohol, polyethylene or polypropylene. They may be woven or knitted from yarns, heat-welded from strips of material, or produced by punching a regular pattern of holes in sheets of material, then stretched into a grid. The geogrids are used for embankments, soft soils, erosion control, highway infrastructure, roadway improvements, reinforced steep slopes, retaining walls, landfill construction. [0004] Nowadays, different types of soil reinforcing techniques are being developed in the construction field to improve the strength and stability behavior of the soil. Adopting the soil reinforcement technique in weak soil has become inevitable as the construction industry is developing rapidly in all corners of the world. The use of geo synthetics for reinforcing the soil is presently being followed across the world in widely. Compared with the present techniques of soft ground engineering, if a new method is developed with economic cost and high efficiency, there may be a high demand in the market for that. Geocells is one such soil reinforcement method which was developed after 1975 by U.S. Military Corps. A lot of researches have been carried out to increase the efficiency of the geocells with cheaper rates than the former.

[0005] Geocells which are also known as 3-D geo-synthetic confinement system or cellular confinement system (CCS) have a large number of applications in the construction field such as slope stabilization, channel protection, structural reinforcements etc. The geocells are formed by ultrasonic welding of High Density Polyethylene sheets or Novel Polymeric alloy sheets with giving some perforations to have an interconnection between the soil particles. It is expanded on site to form a 3D Honeycomb or cellular like structure as shown below and the cells are filled with the different infill materials such as gravel, rock, sand, soil and so on. This method of soil reinforcement will increases the shear strength of the soil which results in the increased bearing capacity. Listed below are some of the important fields where the geocells find application: highways, railways, unpaved access, haul & service roads, military, embankments, erosion control - slopes, retaining walls, channels & shorelines, geo membrane protection, retaining walls and so on.
[0006] The honeycomb shape of the interconnected cell walls in the geocells will completely encase the infill material and provide all-round confinement. During vertical loading, hoop stresses within the cell walls and earth resistance in the adjacent cells increases the stiffness and the load-deformation behavior of the soil. Thus the soil-geocell layers acts as a stiff mat and distribute the vertical loads over a much larger area of the subgrade soil.
[0007] However, commercially available polymer based geogrids and geocells are very harmful to the soil. Further, the commercially available geogrids are made of polymer materials such as high density polyethylene, polypropylene, novel polymeric alloy and so on and these polymer based materials may not allow the roots of the saplings to penetrate through the soil mass in case of slope stabilization problems. Hence, there is a need for finding an alternative material for geogrids which is not harmful for the soil.
[0008] Therefore, there is a need to develop a method for producing geocells and geogrids using an organic material that may not induce any harm to the soil. Further,

the organic material has to allow the roots of the saplings to penetrate through the soil mass.
OBJECTS OF THE INVENTION
[0009] Some of the objects of the present disclosure are described herein below:
[00010] A main object of the present invention is to provide a method for producing
geocells and geogrids using Areca leaf sheath for civil engineering applications.
[00011] Another object of the present invention is to provide a method for producing
geocells and geogrids using Areca leaf sheath that is not harmful for the soil.
[00012] Still another object of the present invention is to provide a method for
producing geocells and geogrids using Areca leaf sheath that allows the root of the
saplings to penetrate through the soil.
[00013] Yet another object of the present invention is to provide a method for
producing geocells and geogrids using Areca leaf sheath which is cheaper in
comparison to commercial HDPE geocells and geo grids.
[00014] Another object of the present invention is to provide a method for producing
geocells and geogrids using Areca leaf sheath that has a tensile strength four times
higher than the commercial geo grid.
[00015] The other objects and advantages of the present invention will be apparent
from the following description when read in conjunction with the accompanying
drawings, which are incorporated for illustration of preferred embodiments of the
present invention and are not intended to limit the scope thereof.
SUMMARY OF THE INVENTION
[00016] In view of the foregoing, an embodiment herein provides a method for producing geocells and geogrids using Areca leaf sheath. The method comprising the steps of, soaking the Areca leaf sheath in water for a predetermined time, pressing the soaked Areca leaf sheath under a hot press with a predetermined pressure to obtain flat Areca leaf sheath, drying the flat Areca leaf sheath in air for a predetermined duration, obtaining a plurality of strips by cutting the soaked Areca leaf sheath of predetermined

width, weaving the strips together to form an Areca grid of predetermined size, and tying the Areca grids using threads to form Areca cells as shapes similar to geocells. [00017] According to an embodiment, the predetermined width of the strips is in the range of 1mm to 10 mm. The predetermined time for soaking the Areca leaf in the range of 10 to 30 minutes. The weaving pattern for the Areca strips includes plain weave pattern, satin weave, twill weave, Herring bone pattern, and so on. [00018] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF DRAWINGS
[00019] The detailed description is set forth with reference to the accompanying
figures. In the figures, the left-most digit(s) of a reference number identifies the figure
in which the reference number first appears. The use of the same reference numbers in
different figures indicates similar or identical items.
[00020] Fig. 1 illustrates the method for producing geocells and geogrids using Areca
leaf sheath, according to an embodiment herein;
[00021] Fig. 2 illustrates the geocells made of Areca leaf according to an embodiment
herein;
[00022] Fig. 3 illustrates a tensile stress-strain behavior of reinforcing material,
according to an exemplary embodiment herein;
[00023] Fig. 4a illustrates a 2D schematic view of a plate load test setup, according to
an exemplary embodiment herein;
[00024] Fig. 4b illustrates a laboratory setup view of a plate load test setup, according
to an exemplary embodiment herein;

[00025] Fig. 5a illustrates a bearing pressure vs. settlement for the Areca grid of single
layer with different embedment depths, according to an exemplary embodiment herein;
[00026] Fig. 5b illustrates a bearing capacity-settlement comparison of different type of
geogrids, according to an exemplary embodiment herein;
[00027] Fig. 5c illustrates a bearing pressure - settlement comparison of different
layers of Areca grids, according to an exemplary embodiment herein; and
[00028] Fig. 5d illustrates a bearing pressure - settlement comparison of different soil
reinforcements, according to an exemplary embodiment herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[00029] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. [00030] As mentioned above, there is a need to develop method for producing geocells and geogrids using an organic material that may not induce any harm to the soil. The embodiments herein achieve this by providing a method for producing geocells and geogrids using Areca leaf sheath. Referring now to the drawings, and more particularly to FIGS. 1 through 5d, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments. [00031] Fig. 1 illustrates the method 100 for producing geocells and geogrids using Areca leaf sheath 102, according to an embodiment. Areca leaf sheath 102 is a natural and biodegradable material. Each Areca nut tree 101 sheds 10-15 leaves per year and is available abundantly. At present, major application of this Areca leaf sheath 102 is for the manufacturing of plates, cups etc. Because of the huge availability manufacturing of slippers using this has started recently at small scale.

[00032] According to an embodiment, the leaf sheaths 102 obtained from the farm are highly heterogeneous having variations in structure, shape and thickness. The rear end is thicker and the two edges are thinner. For example, the thickness at the center ranges from 3.0 to 8.5 mm (average 5.0 mm). A comparatively homogenous piece of fairly uniform thickness and size 50-65 x 20-25 cm can be obtained if a piece of about 10 cm length from either sides along the grain direction, 5 cm from the distal and 10-15 cm from the end across the grain direction are trimmed out from the sheath. Further, to get a flat sheath of uniform thickness and to remove the buck lings of folds, the sheath can be flattened under pressure and heat. For this, the sheaths can be soaked in water to about 75 per cent moisture and then can be pressed for 30 min in a hot Plate press at 4 kg/cm2 pressure and 110°C temperature. This process can give flat sheaths of 1.0-1.5 mm thickness with about 12 per cent moisture. To prevent fungal growth on the sheath surface, it can be soaked in 1 per cent copper sulphate solution for 24 hours before pressing. The pressed sheaths can be then air dried for one hour or longer. The Areca grids 103 which were used as the comparison material for geocells were made by maintaining similar dimensions as that of the geogrids. The Areca leaf sheath 102 is soaked in water for 10 to 15min and is cut into strips of width 10mm. These strips were woven together to form Areca grid.
[00033] According to an embodiment, the method for producing geocells and geogrids using Areca leaf sheath 102 comprising the steps of, soaking the Areca leaf sheath 102 in water for a predetermined time, pressing the soaked Areca leaf sheath 102 under a hot press with a predetermined pressure, drying the flat Areca leaf sheath 102 in air for a predetermined duration, obtaining a plurality of strips by cutting the soaked Areca leaf sheath 102 of predetermined width, weaving the strips together to form an Areca grid of predetermined size, and tying the Areca grids 103 using threads to form Areca cells as shapes similar to geocells. The side view 104 and top view 105 of the Areca cell is shown in fig. 1.
[00034] According to an embodiment, For example, the predetermined width of the strips is in the range of 1mm to 10 mm. For example, the predetermined time for

soaking the Areca leaf in the range of 10 to 30 minutes. The weaving pattern for the
Areca strips that may include but not limited to plain weave pattern, satin weave, twill
weave, Herring bone pattern, and so on.
[00035] Fig. 2 illustrates the geocells made of Areca leaf and commercial geo cell 200
according to an embodiment. The Areca cells 202 which were used as the alternative
material for geocells were made by maintaining similar pocket size as that of the
geocells 201. The Areca grids 103 are tied together using thick threads to make it as a
shape similar to geocell 201 and is called as Areca cells 202.
[00036] The properties of the Areca cells and Areca grids 103 are listed below.

Examplary experimental studies and results:
[00037] Fig. 3 illustrates a tensile stress-strain behavior 300 of reinforcing material, according to an exemplary embodiment. According to an exemplary embodiment, the tensile tests (stress 301 - strain test 302) were carried out on the geocell material and Areca leaf sheath 102 conforming to ASTM D6637-01. The tensile test was carried out following the procedure of multi-rib tensile method of geogrids as per ASTM D6637. A sample of 50mm gauge length, 75mm width, and 2mm thickness of woven Areca grid 303, HDPE geocell and polypropylene geo grid 304 is tested for obtaining maximum tensile strength. The total length of the sample including the gauge length will be 150mm i.e. a 50mm extended on both sides as grip length. The specimen is subjected to tensile testing at the rate of 10% per minute of the gauge length i.e. for 50mm specimen, the speed of the machine will be 5mm/min. The speed of the machine is fixed according to the ASTM D6637. The tests showed that the maximum tensile

strength of the Areca leaf sheath 102 is four times than that of the polyethylene geocell material.
[00038] Fig. 4a illustrates a 2D schematic view 400a of a plate load test setup, according to an exemplary embodiment. The model plate load tests were conducted in the tank 410 assembled with the loading or reaction frame 401 and hydraulic jack 402. The tank 410 is made up of thick steel plates and glass on the front side. The foundation bed made of clay 409 was laid in the tank with dimension 500 mm X 400mm sides and 400mm in height. The sand 408 which is used as the foundation bed is made to fall from a constant height. The sand 408 is compacted in 25mm thick layers to achieve the desired height. The same method was carried out in performing all the tests. The square steel footing 405 used in this study is of dimensions 100mm side and 10mm thickness. The load is applied through a manually operated hydraulic jack 402 arrangement. The clayey soil 409 which is used as the foundation bed was mixed with a predetermined amount of water and filled in the tank 410. The soil was filled by uniformly compacting 25 times using metal rammer equally in five layers to achieve the desired height of the foundation bed. The bed was kept undisturbed for three days for uniform distribution of the moisture.
[00039] According to an exemplary embodiment, the sand which is used as the infill material for the reinforcing materials is made to fall from a constant height. The sand 408 was also compacted in 25mm thick layers to fill the cell pockets. The same method was carried out in performing all the tests. The square steel footing 405 used in this study is of dimensions 100mm side and 10mm thickness. The load is applied through a manually operated hydraulic jack 402 arrangement. The sides of the tank 410 walls were coated with a thin layer of polyethylene sheets in order to avoid the side friction. The footing 405 is placed on the sand bed such that the centre of axis of the tank and the footing coincides with each other. A load cell 404 is placed in between the hydraulic jack 402 and the footing 405 to measure the load applied to the soil bed. The settlement of the footing 405 was noted by placing two dial gauges of 50mm capacity.

[00040] Fig. 4b illustrates a laboratory setup view 400b of a plate load test setup, according to an exemplary embodiment. According to an exemplary embodiment, the laboratory setup view of a plate load test setup is shown in fig. 4b. The tests were conducted on the Areca grid 407 reinforced sand beds by placing the grid at various depths to find out the effective depth of placement of the grid. After finding out the effective depth, the performance of the Areca grid 407 is compared with that of the geogrid and coir grid. The tests on the multi layered Areca grids 103 were also carried out to compare the performance. The model plate load tests were carried out until the footing settlement (S/B) reaches 50% as the failure is gradual for soil reinforced with different types of materials. The tests with a single layer of Areca grid 407 were performed for five different embedment depths (z) such as at z = 10cm, 20cm, 33cm, 50cm and 100cm from the bottom of the footing 405.
[00041] Fig. 5a illustrates a bearing pressure vs. settlement for the Areca grid 500a of single layer with different embedment depths, according to an exemplary embodiment. The tests were conducted on the Areca grid 504 reinforced sand beds by placing the grid at various depths to find out the effective depth of placement of the grid. A graph for bearing pressure (bearing capacity) 501 vs. footing settlement 502 plotted for analyzing the results of the model load plate test. The test on unreinforced soil 503 shows a sudden failure after 10% of the footing settlement. But due to the provision of reinforcements, a gradual failure was observed and when the Areca material 504 was used as the soil reinforcement, it yielded a higher bearing capacity as compared to that of the commercially available geo synthetics. The maximum bearing capacity was found at Z/B = 0.33 i.e. at 33cm from the bottom of the footing.
[00042] Fig. 5b illustrates a bearing capacity-settlement comparison of different type of geogrids 500b, according to an exemplary embodiment. The results of the tests carried out to compare the performance of Areca grid 505 with the coir grids 507 and geogrids 506 are as shown in fig. 5b. The Areca grids 505 were proved to give better performance as compared to others.

[00043] Fig. 5c illustrates a bearing pressure - settlement comparison of different layers 500c of Areca grids 103, according to an exemplary embodiment. The tests with one layer 508, two layers 509, three layers 510 and four layers 511 were performed at optimum embedment depth i.e. at Z = 0.33B. The spacing between each layers and the distance from the base of the footing to the first layer is maintained to be constant as 0.33B. The maximum performance was observed while providing the four layers of grids as compared to the others.
[00044] Fig. 5d illustrates a bearing pressure - settlement comparison of different soil reinforcements 500d, according to an exemplary embodiment. The tests were conducted on the unreinforced clay bed 503, Geocell reinforced clay bed 512, Geocell + Geogrid reinforced clay bed 513, Areca cell reinforced clay bed 514, Areca cell + Areca grid reinforced clay bed 515. The model plate load tests were carried out until the footing settlement 502 (S/B) reaches 50% as the failure is gradual for soil reinforced with different types of materials. The bearing pressure 501 - settlement 502 behavior of the unreinforced and different types of soil reinforcements used in this study are represented in the Fig. 5d. The test on unreinforced soil shows a sudden failure after 10% of the footing settlement. But due to the provision of reinforcements, a gradual failure was observed and when the Areca material was used as the soil reinforcement, it yielded a higher bearing capacity as compared to that of the commercially available geocells. As observed from the previous researches, an increase in the bearing capacity was observed due to the provision of two dimensional grids in addition to the three dimensional cells. From the above results, the bearing capacity of the soil reinforced with the combination of Areca cell & Areca grid is found to be higher when compared to all the others. The bearing capacity of the combination -Areca cell 202 & Areca grid is found to be approximately 1.25 times greater than that of the commercial geocell 201 & geogrid combination.
[00045] According to an exemplary embodiment, Areca cells were found to be highly cost effective and environment friendly material that can be used in place of the polymer based commercially available HDPE geocells. The tensile strength of the

Areca woven grid is four times higher than that of the HDPE geocell. However, the strain percentage was found to be less in Areca as compared to the HDPE geocells and hence Areca cells can be recommended to use only in low strain geotechnical applications. The bearing capacity of the geocell reinforced soil is found to be 2.5 times higher than that of the unreinforced soil whereas for the Areca cells it is found to be increased by 2.8 times. When the 2D grids were used in addition with the 3D cells it showed a better confinement than that of using 3D cells alone. The bearing capacity of the geocell & geogrid reinforced soil is found to be three times higher than that of the unreinforced soil whereas for the Areca cells & Areca grids 103, it is found to be increased by 3.8 times. Hence, it is recommended to use the 2D grids along with the 3D cells for better performance.
[00046] According to an embodiment, some of the important fields where the geocells find applications are highways, railways, unpaved access, military, embankments, erosion control in slopes, retaining walls, channel protection. As the Areca cells are having lower strain percentage as compared to that of the geocells, it can be limited to use only in low strain geotechnical engineering applications. Also these Areca cells can be used in slope stabilization. Some vegetation can be grown along the slopes whose roots can hold the soil intact after the life time of geocells. A good example for this is Vetiver which is a perennial bunchgrass of the Poaceae family. It can grow up to 150cm in height and form clumps along its width. The roots of the Vetiver can grow downwards from 2 to 4 metres in depth. The Areca cells allow the roots to penetrate deep into the soil whereas the polymer material won't allow this. After the lifetime of Areca cells or Areca grids 103, this roots of Vetiver acts as a better soil reinforcement material than any other available methods.
[00047] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the

meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

We Claim:
1. A method for producing geocells and geogrids using Areca leaf sheath 102
comprising the steps of,
soaking the Areca leaf sheath 102 in water for a predetermined time;
pressing the soaked Areca leaf sheath 102 under a hot press with a
predetermined pressure to obtain flat Areca leaf sheath 102;
drying the flat Areca leaf sheath 102 in air for a predetermined duration;
obtaining a plurality of strips by cutting the soaked Areca leaf sheath 102 of
predetermined width;
weaving the strips together to form an Areca grid 103 of predetermined size;
and
tying the Areca grids 103 using threads to form Areca cells 104 as shapes
similar to geocells.
2. The method of claim 1, wherein the Areca leaf sheath 102 further soaked in copper sulphate solution to prevent fungal growth.
3. The method of claim 1, wherein the predetermined width of the strips is in the range of 1mm to 10 mm.
4. The method of claim 1, wherein the predetermined time for soaking the Areca leaf in the range of 10 to 30 minutes.
5. The method of claim 1, wherein the weaving pattern for the Areca strips includes plain weave pattern, satin weave, twill weave, Herring bone pattern, and so on.
6. The method of claim 1, wherein the Areca cells formed in a honey comb structure to increase a tensile strength of the geocells.

7. The method of claim 1, wherein the Areca grids 103 utilized in civil engineering application in multiple layers to increase a bearing capacity of the geogrid.