KR20040064667A - Geogrid of high molecular polymer material produced by laser welding and production method thereof - Google Patents

Abstract

PURPOSE: A geogrid of a high molecular polymer material and a production method thereof are provided to improve the durability and the safety of various constructions and structures by reinforcing the tension strength. CONSTITUTION: High molecular polymer bands are layered in a lattice shape. The high molecular polymer bands are welded and stuck together at a short time by irradiating a laser on many contacts to cross the high molecular polymer bands each other. A geogrid(1) is cheap in production cost, has excellent tension strength and excellent combining force with earth and concrete, and secure excellent processing efficiency and the mass-productivity.

Description

Geogrid made of high molecular polymer material produced by laser welding and its manufacturing method.

Recently, geosynthetics is applied to soil-related fields such as soft ground reinforcement, retaining wall protection, drainage, slope stability. Such geotextiles have been widely used because they are simple to use, easy to transport, excellent in functionality and physical properties, and economically advantageous compared to poor construction such as gravel, sand, and giant, which have been conventionally used.

Geosynthetic fiber, a synthetic polymer product that was developed and applied in the early 1960s, has excellent durability, constructability, and economic feasibility, thus preparing new electricity in civil engineering. However, geotextile products, such as woven fabrics and nonwoven fabrics, which have been used as reinforcement materials for various civil structures until the 1970s, have limitations in terms of tensile strength, tensile modulus, creep, and so on, which require high tensile strength and tensile modulus. The application of has been limited. This problem was solved by the emergence of geogrid, a high-strength geotextile product developed in the United Kingdom in 1979. Since then, the geogrid has been rapidly developed as it is used for various purposes in various civil works around the world.

In Korea, the use of geogrids has been sought since the 1990s, and in 1993, geogrids were first applied to the design of reinforced earth retaining walls.In the late 1990s, the use of geogrids has become active as domestically produced soft-bonded geogrids have been coated. (Korea Institute of Construction Technology, 1999).

Geogrid is widely used as a reinforcement material in various civil works such as soft ground reinforcement, fill slope reinforcement, reinforcement soil retaining wall, etc. There is still uncertainty regarding durability. The degree of degradation of the engineering properties (especially tensile strength) of geogrid stiffeners over time may vary depending on the material and shape of the geogrid, the environment around which the geogrid is laid, and external loads.

In addition, the damage of geogrids that may occur while laying and filling the backfill soil on top of the geogrid reinforcement when constructing the reinforcement soil structure may also have a significant impact on the long-term stability of the reinforcement soil structure. Particularly in Korea, granite weathering soil (mountain soil), which is widely used as backfilling soil, contains a lot of stones with large particle size, and it is difficult to supply high quality earth and sand and have to remove large amount of backfilling soil during site construction. As a result, soil containing a large amount of stone with a particle size of more than 19 mm (backfill selection criteria) is used, and there is a great concern for damage to the geogrid reinforcement.

Geotextiles can be broadly classified into extrusion moldings, geotextiles, non-woven fabrics. In the case of nonwoven fabrics, those manufactured by spunbonding are suitable. In particular, geotextiles include geogrids and geomats. These are mainly manufactured by weaving polyester yarns and then polyvinyl chloride (PVC) coating.

Geogrid has a lattice structure and improves the cohesion of soil by mutual affinity with soil in the ground, and prevents the collapse and settlement of the ground, and is used for soft ground reinforcement, retaining wall protection, and slope reinforcement.

This geogrid is a material with a lattice in the direction of warp and weft (primary and secondary ribs), which can vary the composition, cross-connection, or joining method of the strip, and is used as structural reinforcement in the direction of load. . Geogrids are made of plastic (rigid, sheet) geogrids and textile (soft, woven) geogrids.Plastic geogrids are manufactured by drilling holes in sheets of high-density polyethylene or polypropylene obtained through an extruder and then uniaxially or biaxially stretching them. Geogrid is prepared by laminating or weaving synthetic fibers in lattice form to coat resins such as polyvinyl chloride, acrylic, latex, rubber, and bitumen.

In particular, the textile geogrid is known to be relatively advantageous in terms of packaging, transportation, and construction because it is more economical in terms of manufacturing cost and more flexible than the plastic geogrid.

However, despite these advantages, the textile geogrid has some problems in its manufacturing process.

First, the process of knitting, knitting and synthetic resin coating process are separated using synthetic fibers. Therefore, when transferring the knitted fabric to the coating process, the lattice shape of the fabric should be disturbed or limited to a certain amount of volume. In the case of coating work, there is a problem in that the economical efficiency is lowered because the loss (loss) generated at the start and end of each coating lot (lot) leads to a decrease in the production yield, which leads to a cost increase and a hassle of work.

In addition, since the component is a synthetic fiber, the original physical properties, i.e., modulus or elongation, are changed by the high temperature thermal history received in the coating process, and especially in the case of elongation, a significant rise in relation to heat shrinkage is achieved. There are problems such as exceeding the limit elongation (usually less than 15%) or the tensile behavior is changed during the tensile test of the product, the strength is lowered.

Problems that occur in manufacturing a geogrid using conventional yarns are as follows.

When using low shrinkage yarns, the shrinkage stress is low, so the shrinkage stress is low, so there is little problem in the process of PVC coating.However, due to the low strength, the amount of yarn used is needed to express the required strength of the product. This is high, the problem of weaving is difficult due to the increase in the number of yarns used, which is difficult to express a certain level of strength. In addition, low shrinkage yarns have high elongation, making it difficult to express high-modulus (elastic modulus, which represents the ratio of stress and strain) in geogrid products.

If high strength yarns are used, the strength and modulus of the yarns are not a big problem.However, due to the high heat shrinkage force in the PVC coating process, the coating loss due to shrinkage is high, resulting in high manufacturing costs, and a high temperature PVC coating process. Due to the shrinkage force at the tenter pin or the grip may cause a process problem that the coating is impossible due to separation from the grip, the higher the shrinkage rate is more severe this tendency. In addition, even if there is no problem in the process, the physical properties of the yarn is severely changed due to the high shrinkage during the heat treatment, in particular, the elongation is greatly increased, the geogrid product is difficult to express the characteristics of high modulus.

Such products according to the prior art have a disadvantage in that the fabrication method and apparatus are very complicated and the tensile strength of the product is very weak in terms of the characteristics of the product, so that the original functionality of the geogrid serving as a reinforcing core material cannot be sufficiently achieved.

In view of the above-mentioned problems, the present invention can mass produce geogrids at a more economical production cost, and in particular, to strengthen the tensile strength significantly compared to products known to date, and thus, various constructions and constructions for use of geogrids. It is to greatly improve the durability and safety.

1 is a partial perspective view of a soft ground strengthening geogrid of the present invention.

2 is a partial perspective view of the retaining wall strengthening geogrid of the present invention.

3 is a schematic drawing of the drawing step of the present invention.

<Explanation of symbols on the main parts of the drawing>

1: geogrid 2: main rib

3: secondary rib 4: polymer polymer strip

10: extrusion machine 20: cooling unit

30: cooling water tank 40: mendrel

50: blower 60: first stretching machine

70: heater 80: second drawing machine

90: third stretching machine 100: support

110: presser 120: winder

130: first room temperature drying roller 140: second room temperature drying roller

The present invention is a geogrid, a planar geosynthetic product consisting of a lattice network of tensile members made of synthetic polymer materials used in various civil engineering, etc., wherein the polymer polymer bands stretched at an appropriate level are vertically stacked in a grid network at right angles to each other. The present invention relates to a geogrid of a polymer polymer material produced by laser welding, wherein the polymer polymer band is manufactured by melting and bonding a plurality of contacts at a time when the polymer band is intersected with another band.

The present invention is characterized in that the laser welding through the adhesive agent between the upper and lower bands of the polymer polymer laminated with the lattice network.

The present invention is characterized in that the welding agent interposed between the upper and lower bands of the polymer is an aluminum welding agent.

When the geogrid of the present invention is manufactured for soft ground reinforcement, the lattice hole size of the grid is square with 27-36mm of spacing between ribs, the thickness of each rib is 0.5-1.5mm, and the width of each rib is 5-12mm. And the number of main ribs and auxiliary ribs is 50 to 52 polymers per 2m, respectively.

The geogrid of the present invention is a rectangular lattice hole size of 56 to 73 mm between the main ribs and 27 to 36 mm between the secondary ribs, and the thickness of each rib is 0.5 to 2 mm. The width of the ribs is 10-20mm, the width of the auxiliary ribs is 5-12mm, the number of main ribs is 25-27 per 2m, and the number of auxiliary ribs is 50-52 each 2m. It is made of a high molecular polymer material.

The geogrid of the present invention is the main rib of the grid is 5 to 12 tons of tensile strength per unit, the tensile strain is 4 to 8% at the maximum tensile strength, the auxiliary rib is 4 to 11 It is ton, and the tensile strain at the maximum tensile strength is a polymer polymer material produced by laser welding, characterized in that 4 to 8%.

Geogrid of the present invention is the contact strength of the main rib and the auxiliary rib of the grid is 50 to 70kg when the tensile strength is 5 to 6 tons, 90 to 110kg when 7 to 9 tons, 110 to 130 kg when 10 to 12 tons It is characterized by.

The present invention provides an agent for producing a polymer polymer band in which the tensile strength, elongation rate, biochemical durability and supporting resistance of the band are reinforced by extruding the polymer polymer in the form of a band through an extruder, then cooling and stretching it again. Step 1; The stretched polymer polymer strip is woven into a lattice mesh, and the polymer polymer strip which is melted and bonded by irradiating a laser on a straight line or a diagonal direction to a plurality of contacts where the polymer polymer strip intersects the other strip is generally lattice-shaped. It relates to a geogrid manufacturing method comprising the step of combining with.

In the first step of the manufacturing method, the stretching step of forming the polymer polymer into strips is completely dried in order to prevent decomposition of the polymer in the melting process before the polymer polymer chip is introduced into the extruder, and the extrusion molding machine uses the polymer polymer chip. Melted and extruded into a die, the melted polymer is extruded by the pressure extruder extrudes through a circular die with optimized spacing, and is immediately cooled by the water of the cooling section consisting of Mandrel and a cooling bath, In order to go through the stretching process, the polymer polymer extruded from the extruder is connected to the roller of the first drawing machine through the mandrel, and the polymer strip drawn from the first drawing machine is heated through the heater, and then The drawing process is done through three drawers, and the finished polymer band is used to slowly cool the support at room temperature. It is connected to the first room temperature drying roller located in the upper part of the third drawing machine, and passes through the second room temperature drying roller located in the upper part of the first drawing machine, and then the surface is embossed while passing through the compactor. It is connected to a winder and wound on a roll. In the drawing process, the polymer band is continuously connected from the extruder to the winder, and the edge of the first extruded polymer band has a difference in uniformity and physical properties compared to other parts. Since the edge of the polymeric polymer strip is cut off and wound on the winder device, characterized in that it comprises the step of producing a polymeric polymer strip.

In the geogrid, a planar geosynthetic product consisting of a lattice network of tensile members made of synthetic polymer materials used in various civil engineering projects, the polymer polymer bands stretched at an appropriate level are stacked vertically and vertically in a lattice mesh shape. The present invention relates to a geogrid of a polymer polymer material dried by laser welding, characterized in that a plurality of contact points at which a polymer polymer band intersects another band are produced by melting and bonding a laser beam in a short time.

The bonding of the geogrid by the laser welding as described above is superior to the adhesive force by the bonding in the evaluation after the resistance test than the method by the ultrasonic welding, and the breakage or detachment state of the joint after the compacting work is good. In other words, the breakage or detachment state of the bonded part by ultrasonic welding is caused by the melted or detached part of the polymer polymer band and the unbonded part of the bonded part. On the other hand, the bonded part by laser welding maintains the tensile strength and stiffness of the polymer polymer band part at the joint part even when the polymer polymer band is melted and only part of the bonded part is separated or a total detachment occurs. There is an advantage that the phenomenon that the band itself is cut does not occur.

In addition, the bonding state of the bonded portion by ultrasonic welding has a problem in that the melt of the polymer polymer band flows out of the intersection point to generate impurities, but in the bonded state of the bonded portion by laser welding, the melt flows out of the intersection point. Since the bonded state is kept smooth without coming out, the appearance of the product has a very beautiful advantage.

In irradiating a laser to a plurality of contacts where the polymer polymer band intersects another band, a welding agent is interposed between the contact points where the polymer polymer band intersects, which deposits the energy of light irradiated by the laser upon bonding by laser welding. I act as a reactant, absorbing laser energy and starting a chemical reaction to raise the required energy level to the desired temperature to melt the polymer polymer strip.

There are many types of solvents present, but in the present invention, the aluminum solvent is sufficient to absorb the laser energy and to initiate the desired chemical reaction up to the melting temperature of the polymer band.

Embodiments of the method of manufacturing the geogrid of the present invention are as follows.

As a first step for producing the geogrid of the present invention, the tensile strength, elongation, biochemical durability and bearing resistance of the strips are obtained by extruding the polymer polymer in the form of a band through an extruder, then cooling and stretching it again. Drawing step of producing reinforced polymer strips; In the second step, the stretched polymer polymer band is woven into a lattice mesh, and the polymer polymer band is melted and bonded by irradiating a laser in a direct or diagonal direction (a predetermined angle) to a plurality of contacts where the polymer polymer band intersects another band. The polymer polymer strip is combined into a lattice mesh as a whole shape.

In the manufacturing method of the geogrid of the present invention, in the first step, the stretching step of the polymer polymer into a strip shape is completely dried to prevent decomposition of the polymer in the melting process before introducing the polymer polymer chip into the extruder, The extruder melts the polymer polymer chips and extrudes them into a die, and the molten polymer is extruded in the form of a bar by the pressure extruded by the extruder through a circular die with optimized spacing, and immediately after the Mandrel It is cooled by the water of the cooling unit consisting of and a cooling water tank.

Thereafter, the polymer polymer extruded from the extruder for the stretching process is connected to the roller of the first drawing machine via the mandrel and stretched to an appropriate level. The polymer band drawn from the first drawing machine is heated through a heater and then drawn through the second and third drawing machines.

After finishing the stretching process, the polymer band is connected to the first room temperature drying roller located at the upper part of the third drawing machine via a support to gradually cool down at room temperature, and then passes through the second room temperature drying roller located at the upper part of the first drawing machine. As it passes, the surface is embossed and then connected to the capstan and winder and wound on a roll.

The temperature of the polymer polymer melted in the extruder is about 260 ~ 275 ℃, the temperature of the polymer polymer band connected to the first stretching machine through the cooling bath is cooled to about 90 ~ 120 ℃, which is the polymer polymer band in the first stretching machine It is a suitable temperature for stretching.

The polymer polymer strip cooled by the cooling bath is connected to the first stretching machine via a support wrapped with cloth or cloth to remove moisture on the surface. In addition, a blower for air drying is installed between the cooling water tank and the stretching machine in order to completely remove water from the polymer polymer band by blowing air perpendicularly to the direction in which the band proceeds. The degree to which the polymer polymer band is cooled at room temperature may be kept constant in the process of performing stretching in the drawing machine by completely removing the water on the polymer band.

In addition, in the manufacturing method, the polymer polymer strip is heated in three stages in a heater, in which the first stage is heated to 120 to 140 캜, the second system is heated to 100 to 120 캜, and the third stage is heated to 80 to 100 캜.

The polymer polymer strip may be passed through a buffer and a clamper so as to be wound around the roll by a winder.

In the drawing process, the polymer strip is continuously connected from the extruder to the winder, and the edge of the first extruded polymer strip has a difference in uniformity and physical properties compared to other portions. Thus, the edges of the polymer strip are cut out and connected to the winder device.

The water-cooled polymer polymer strip has an amorphous structure and obtains mechanical properties such as tensile strength, elongation rate, and biochemical durability required as a geogrid through the stretching process. In the stretching step, stretching in the vertical and horizontal directions occurs at the same time, and stretching is performed by expanding each of the rollers of the stretching machine by the speed difference at which the rollers rotate.

As the band-shaped expanded water-cooled polymer passes through the stretching roller of the stretching machine, it is stretched to meet the appropriate requirements such as tensile strength, elongation rate, biochemical durability, and the stretching roller of the stretching machine is arranged in two rows of upper and lower sides. The rollers and the rollers on the lower side are arranged diagonally at a constant angle.

The polymer band produced in the stretching step has the following characteristics.

First, in the maximum tensile strength test using one band to determine the quality of geogrid products, the tensile strain is 5 to 13 (t / m) and the tensile strain is 5 to 8%. The test was conducted according to the method specified in GSI-GG1 among the test methods proposed by ISO 10319 and the Geotextile Research Institute of Drexel University.

Second, the bending stiffness of the polymer band is 1 * 10 ⁶ -5 * 10 ⁶ . The result of the flexural stiffness is the result of testing by the cantilever method among the methods standardized in ASTM D1388-96.

Third, the physical properties of the polymer polymer bands are 0.5 to 2 mm in thickness and 5 to 20 mm in width.

In the manufacturing method of the geogrid of the present invention, the second step is a plurality of contact portions in which the stretched polymer polymer strip is divided into warp and weft in a lattice mesh and weaved perpendicularly to each other so that the warp and weft are in contact with each other. This is a step of manufacturing a geogrid in which the overall shape of the polymer polymer band is formed into a lattice network by melting and bonding the same by irradiating a laser to the laser.

Bonding by the laser is an excellent advantage.

First, the light energy per unit area on the focal plane of the laser focused by the lens is very large.

Secondly, there is a directional direction, no matter how far it is, the intensity of light hardly decreases.

Lasers have not yet been found in nature on Earth and can only be obtained by artificial manipulation. The laser is produced through the medium, and different media are used depending on the type of laser device. That is, the medium generating the laser can be in the gas, liquid, or solid state. According to the type of medium, it is classified into four types: gas laser, liquid laser, solid laser and semiconductor laser.

Gas lasers include argon lasers, krypton lasers, helium neon lasers, and carbon dioxide lasers. Liquid lasers include die lasers, and solid lasers include yag lasers, ruby lasers, hallum lasers, and diode lasers.

By controlling the properties of the high brightness and high power of these lasers in the energy dimension it can be used in various fields.

Lasers are very pure compared to normal light and do not spread and go straight ahead. It is light with only one type of wavelength, monochromatic light with a uniform phase, and can be focused at a very small area by concentrating the laser with a lens. The light energy per unit area on the focal plane of the laser focused by the lens is very large. The density is about 1011 W / cm 2. This is enormously large compared to the energy density of the solar surface at 104 W / cm2. In addition, since the laser beam has a narrow line spectrum of butterflies and a sine wave, it is easy to cause interference. There is also a directional direction, no matter how far it is, the intensity of light hardly decreases. The light from fluorescent and incandescent lamps is getting wider as they go forward, but the laser beam is small enough to be used for distance measurement between spaces.

The concentration of energy is also excellent. Collecting sunlight can burn paper or wood, but collecting laser beams not only cuts metal but also fusion.

As described above, the characteristics of the laser beam are excellent in monochromaticity, uniform phase, easy to occur interference, straight ahead without spreading, good light condensation, and high energy density.

Lasers are not only used in many manufacturing industries such as automobile welding, semiconductor DRAM production, but also in various fields such as medical, holography, and optical communication. In laser processing, the technique of drilling holes in hard gemstones or using a large energy density of a laser beam or quickly and accurately drilling holes in watch parts is performed relatively early, and is widely applied to cutting or welding steel plates.

The bonding state of the bonded portion is good by bonding the polymer polymer strip using the laser device as described above, and since the melt bonding is performed in a short time, there is almost no difference in uniformity and physical properties compared to other portions. Since there is almost no difference in tensile strength, elongation, biochemical durability and supporting resistance when buried with other parts, in the present invention, it is preferable to fabricate a rigid geogrid by melting and bonding by bonding a polymer polymer band with a laser beam. It is the summary of the invention.

In general, a laser welder is composed of a laser medium, a gas supply device, a laser cooler, laser resonators (LASER Cavities) and the like. In order to guide the laser beam to the parallel beam, the laser beam oscillated by the oscillator of the laser beam is reflected in the first and second reflection mirrors and the laser beam reflected by the second reflection mirror is focused in the connecting mirror to provide the laser beam guide member. Through it, the joint etc. between the workpieces are welded.

In this way, the laser welding machine nozzles argon gas or nitrogen gas supplied through the shielding gas supply pipe to prevent the laser beam from scattering before the laser beam reaches the joint between the workpieces by the plasma gas generated during the laser welding. Eject from

The laser welding machine includes an automobile fuel tube, an ABS solenoid valve, an injector valve, an automobile fuel tube, an optical packaging, a nuclear fuel rod support grid, an electronic component, a diamond saw laser welder, and the like in terms of use.

Since welding with laser beam does not connect the earth, spark does not occur, and it is easy to weld the corner part and thin core.

The adjustment parameters of the laser welder can be manipulated by computer for temperature, laser power, welding time, focal range, welding pressure, welding speed and the like.

In particular, the plastic laser welding machine is used for welding thermoplastics, elastomers, metals and plastics such as ABS, PE, PET, PP, PC, PMMA, PS, and SAN. The welding principle of the plastic laser welding machine is particularly effective when joining other composite plastic materials because it has light absorption characteristics with respect to the laser wavelength. The laser light passes through the transmission body and is absorbed by the non-transmission body and converted into heat. The plastics melt at the welding surface and are joined by the pressure of the fixture.

In the present invention, the reason why the geogrid is manufactured by joining the regions where the polymer polymer bands cross each other with a lattice network by laser welding is to melt and bond a short time by irradiating a laser to a plurality of contacts where the polymer polymer bands cross. This is because it does not cause problems such as adhesion state, tensile strength and contact strength, safety factor due to shrinkage force in the process of high temperature treatment. In addition, the contact strength of the geogrid should be large enough to support the reinforcement soil in which the geogrid is installed, so that the geogrid buried in the soil does not break the contact due to external load or the shape of the geogrid causes deformation. It must be manufactured.

The method of combining the polymer polymer strips of the present invention in a lattice form to realize the second step of the manufacturing method includes mounting the polymer polymer strips wound in the first step on the main rib feed roller and the auxiliary rib feed roller. And the polymer polymer strip mounted on the main rib feed roller is continuously wound on the take-up roller, and the skew of the polymer polymer strip mounted on the auxiliary rib feed roller is laminated vertically with the main rib polymer band by an automatic jig, When the stacked bands reach the position of the laser exiting part, the laser beams are irradiated with each other by irradiating a laser beam between the bands and the bands, and the auxiliary grids connected to the auxiliary rib feeding rollers are cut to wind up the geogrid of the grid.

Vibration is applied to the main rib and the auxiliary rib fused by the laser irradiation to further enhance the adhesion of the joint portion. The reason for applying the vibration is to remove bubbles generated in the melt during the adhesion of the molten polymer polymer band by laser irradiation, and also to apply the vibration to strengthen the adhesion state.

When the main rib feed roller is a roller in which the polymer polymer band wound in the stretching step is mounted in a roll shape, the roll-shaped polymer polymer band may be 50 to 52 skeins mounted on the main rib supply roller. Although it can be manufactured to mount more tufts on the equipment, the geogrid of the present invention has a total width of 2 m and a suitable number of tufts of 50 to 52 tufts for the lattice spacing or the width of the polymer polymer band.

In the process of stacking the high molecular polymer band mounted on the auxiliary rib feed roller vertically with the main rib polymer band by an automatic jig, an aluminum adhesive should be applied to the band of the auxiliary rib. This means that the aluminum energy of the laser irradiation acts as a reactant, and the chemical reaction starts by absorbing the laser energy during the welding by laser welding, to raise the required energy level to the desired temperature to melt the polymer polymer strip. will be.

Other types of deposition also exist, but in the present invention, the aluminum deposition is sufficient to absorb the laser energy and to produce the desired chemical reaction up to the melting temperature of the polymer polymer strip.

Cutting the auxiliary ribs on the side of the auxiliary rib feed roller after laser welding at the intersection of the main ribs and the auxiliary ribs is to continuously wind the completed geogrid to the winder. This is because if the finished geogrid is wound in the winder without the auxiliary ribs being cut, the auxiliary ribs cannot cross vertically with the main ribs.

The laser emitting unit emits a laser beam for a predetermined time by fusion of the laser beam from the side of the laminated strip under the control of the controller unit, and then reaches the place where the laser exit is located until the next stacked polymer band reaches a predetermined position. Until the laser beam is separated until it is controlled.

The following results were obtained by measuring the geogrid of the present invention prepared as described above.

Tables 1-1 and 1-2 are the results of evaluating the maximum tensile strength and tensile strain which are the basis for calculating the long-term design tensile strength of the geogrid implemented by the present invention. The wide tensile test is a value converted into tensile strength per unit width in consideration of the ratio of the number of ribs per unit width (1 m) to the number of ribs of the 20 cm wide sample used in the test.

Table 2-1 and 2-2 are the results of evaluating the contact strength and the safety factor of the geogrid implemented by the present invention. The contact strength should be large enough so that the geogrid-reinforced reinforcement soils show an integral behavior, so that the geogrid buried in the soil should not be broken or deformed by the external load. In this evaluation, since the method for evaluating the contact strength of the geogrid is not standardized, the method for calculating the minimum contact strength is proposed and used as in Equation 2-1 and Equation 2-2.

Table 3 shows the results of evaluating the stiffness of the geogrid embodied by the present invention. In this test, the protruding length of the sample was measured using the cantilever method and the flexural stiffness was calculated. Equation 3-1 is a formula for calculating the bending stiffness using the measured protrusion length of the sample.

Table 4-1 and 4-2 are the results of evaluating the construction resistance of the geogrid implemented by the present invention. Geogrids installed on the site may be damaged by compacting after the upper piles are laid. The degree of damage varies considerably depending on the type of piles. In this test, four types of soil materials were adjusted by field sifting for granite weathered soil, which is the most widely used soil material in Korea, and used for 25mm crushed stone and rail ballast. 25-60 mm crushed stone was also used.

Tables 4-1 and 4-2 show the results of visual observation of geogrids extracted after the endurance test, and the number of front and back damage points for 2m × 5m sample area of the geogrid used.

In the evaluation of damage in the table, 'weak surface damage' means that the surface of the geogrid is slightly scratched, and 'medium surface damage' means that the degree of scratching is a little bit severe or that the stones are being struck. The severe surface damage refers to a condition where the middle part of the rib is cracked or severely cut, and the 'partial cutting' means a part of the rib section cut into a sharp stone.

As described above, the geogrid manufactured by the laser welding is excellent in engineering properties such as tensile strength, creep property, contact strength, stiffness, durability, friction property, and field application and construction resistance.

In particular, TOTOGRID® shown in the table above is a trademark of a product set for testing, and values such as 4T, 7T, and 10T appearing after TOTOGRID® are the product specifications for tensile strength, and the actual tensile strength according to the test is 11 to 32%. It can be seen that it is designed and manufactured to a great extent, and that an additional safety factor is included as much as that value. In addition, the tensile strain at the maximum tensile strength also shows good tensile strain in the range of 6.68-7.4%.

Geogrid of the present invention in the test results as described above has a preferred configuration considering the tensile strength, creep properties, contact strength, stiffness, durability, friction characteristics and the like.

The geogrid of the present invention, when used for soft ground reinforcement, has a lattice mesh shape, the lattice hole size is 27-36 mm, the interval between each rib is square, the thickness of each rib is 0.5-1.5 mm, and the width of each rib is 5-12 mm. The number of main ribs and auxiliary ribs is characterized in that each 50 to 52 per 2m.

In addition, the geogrid of the present invention used in the retaining wall structure is a lattice mesh, the lattice hole size is a rectangle of 56 ~ 73mm spacing between the main ribs and 27 ~ 36mm spacing between the auxiliary ribs, the thickness of each rib is 0.5 ~ 2mm, The width of the main ribs is 10-20mm, the width of the auxiliary ribs is 5-12mm, the number of main ribs is 25-27 per 2m, and the number of auxiliary ribs is 50-52 each 2m.

The geogrid of the present invention has a tensile strength of 5 to 12 tons per unit of main rib, a tensile strain of 4 to 8% at maximum tensile strength, and a tensile strength of 4 to 11 ton per unit of auxiliary rib, The tensile strain in the tensile strength is characterized by 4 to 8%.

In addition, the contact strength of the molten and bonded portion by irradiating the laser at the intersection of the main and secondary ribs of the geogrid according to the present invention is 50 to 70 kg when the tensile strength is 5 to 6 tons, and 90 to 90 to 7 to 9 tons. It is 110 kg and 110 to 130 kg at 10 to 12 tons.

Polymeric polymers used in the present invention include polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polyethylene (PE) and the like. In particular, the high molecular polymer used is polyethylene terephthalate, which is most suitable because it has the best support, contact, and friction with soil in the behavior of geogrid-embedded soils.

Geogrid of the present invention described above is mainly used as a civil engineering buried material to be used in the same way as the conventional method has the following advantages compared to the existing product.

Geotechnical geogrid should be guaranteed as product characteristics, durability, economics of production cost, ease of construction, etc. The geogrid of the present invention

Firstly, it is a polyester resin extruded product and its cost is relatively low due to mass production.

Secondly, it is uniformly stretched and embossed in order to maintain the elongation of the unit tape uniformly, so the overall tensile strength is very good, and the earth and concrete and the binding force are good.

Third: Since the resin material can be replaced with recycled resin, it has a great effect of environmental preservation by recycling, and can be applied in various ways such as unit tape width, thickness, batch interval, etc. By forming the entire grid, there is an advantage that the processing efficiency and mass productivity are guaranteed without changing the durability.

Claims (9)

In the geogrid (1), which is a planar geosynthetic product composed of a lattice network of tension members made of synthetic polymer materials, which are used in various civil works, etc., the lattice network of the polymer polymer strips (4) drawn at an appropriate level is perpendicular to each other. Of the polymer polymer material produced by laser welding, characterized in that the polymer polymer band 4 is laminated up and down, and the polymer polymer band 4 is melted and bonded in a short time by irradiating a laser to a plurality of contacts intersecting with other bands. Geogrid. The geogrid of a polymer polymer material according to claim 1, wherein the polymer polymer is fabricated by laser welding with a welding agent interposed between upper and lower bands of the polymer polymer laminated with the lattice network. The geogrid of the polymer polymer material of claim 1, wherein the adhesive agent interposed between the upper and lower bands of the polymer polymer is an aluminum welding agent. The lattice hole size of the lattice network is a square of 27-36 mm, the thickness of each rib is 0.5-1.5 mm, the width of each rib is 5-12 mm, and the main rib 2 ) And the number of auxiliary ribs (3) geogrid of the polymer polymer material produced by laser welding, characterized in that 50 to 52 each 2m. The lattice hole size of the lattice network is a rectangular shape wherein the spacing between the main ribs 2 is 56 to 73 mm, and the spacing between the auxiliary ribs 3 is 27 to 36 mm, and the thickness of each rib is 0.5 to 2 mm. The width of the main ribs 2 is 10 to 20 mm, the width of the auxiliary ribs 3 is 5 to 12 mm, the number of the main ribs 2 is 25 to 27 per 2 m, and the number of the auxiliary ribs 3 is 2 m. A geogrid of a polymer polymer material produced by laser welding, characterized in that each is 50 to 52 sugars. The main rib 2 of the grid is 5 to 12 tons of tensile strength per unit, the tensile strain at maximum tensile strength is 4 to 8%, and the auxiliary ribs 3 are 1 meter per unit. A geogrid of a polymer polymer material produced by laser welding, characterized in that the tensile strength is 4 to 11 tons and the tensile strain at the maximum tensile strength is 4 to 8%. The contact strength of the main rib 2 and the auxiliary rib 3 of the grid is 50 to 70 kg when the tensile strength is 5 to 6 tons, 90 to 110 kg when the 7 to 9 tons, and 10 to 10 Geogrid made of a polymer polymer material produced by laser welding, characterized in that 110 to 130kg when 12 tons. In the method of manufacturing a geogrid, a polymer polymer strip in which the tensile strength, elongation rate, biochemical durability, and support resistance at the time of embedding the band is strengthened by extruding the polymer polymer in the form of a band through an extruder, cooling, and stretching it again. 4) manufacturing a first step; The polymer polymer strip is woven by lattice mesh of the stretched polymer polymer (4), and the polymer polymer strip (4) is melted and bonded by irradiating a laser at a direct or diagonal direction to a plurality of contacts intersecting with other bands. Geogrid manufacturing method, characterized in that the overall shape consists of a step of combining the grid. 9. The stretching step of claim 8, wherein the stretching step of stripping the polymer polymer in the first step is completely dried to prevent decomposition of the polymer in the melting process before the polymer polymer chip is introduced into the extruder 10. The molding machine 10 melts and extrudes a polymer polymer chip into a die, and the melted polymer is extruded by the pressure extruded by the extruder 10 through a circular die having an optimized gap, and immediately after the mandrel 40 The water-cooled water is cooled by the water of the cooling unit 20 including the cooling water tank 30, and the polymer polymer extruded from the extruder 10 to undergo the next drawing process is passed through the first mandrel 40. The polymer strip 4, which is connected to the roller of, and is heated in the first stretching machine 60, is heated via the heater 70, and then stretched through the second and third stretching machines 80 and 90. After the stretching process is completed, the polymer strip 4 is kept at room temperature. The second room temperature drying roller 140 connected to the first room temperature drying roller 130 located above the third drawing machine 90 via the support 100 to slowly cool the second room temperature drying roller 140 located above the first drawing machine 60. After passing through), the surface is embossed while passing through the compactor 110, is connected to the capstan and the winder 120 and wound on a roll, in the stretching process, the polymer strip 94 is extruded in the extruder 10. Continuously connected to the winder 120, the edge of the first extruded polymer strip (4) has a difference in uniformity and physical properties compared to the other parts, so the edge of the polymer polymer strip (4) is cut off and the winder ( 120) The method of manufacturing a geogrid, characterized in that it comprises a step of producing a high polymer band (4).