WO2022186720A1

WO2022186720A1 - Polypropylene woven geotextile for constructing drainage systems

Info

Publication number: WO2022186720A1
Application number: PCT/RU2021/000393
Authority: WO
Inventors: Виктория Анатольевна БУНИНА
Original assignee: Виктория Анатольевна БУНИНА
Priority date: 2021-03-01
Filing date: 2021-09-14
Publication date: 2022-09-09

Abstract

The claimed subject matter relates to the field of building and can be used for constructing drainage systems of various types and for creating protective, filtering and reinforcing interlayers in landfills on weak soil and in difficult soil and ground conditions and in road pavements and the like. A filtering woven geotextile is made in the form of a web with plain-woven and twill-woven threads of polypropylene with a melt flow index of 3-5 g/10 min and with the addition of an anti-fibrillation additive of calcium carbonate and a UV stabilizer, wherein threads having a linear density of 700-6000 denier and a width of 4-12 mm with a high degree of fibrillation are used in the weft, and flat threads having a linear density of 1000-4000 denier and a width of 1-4 mm are used in the warp, and the coefficient of permeability of the geotextile is 40 m/day at a pressure of 100-200 kPa. The technical result is a 1.5-2.5-fold increase in the water flow capacity of a drainage system in which the claimed geotextile is used.

Description

POLYPROPYLENE WOVEN GEOTEXTILE FOR DRAINAGE SYSTEMS

Technical field

The invention relates to the field of construction and can be used for the device of various types of drainage systems, the device of protective-filtering and reinforcing layers in embankments on soft soils and in difficult soil and geological conditions and bases of pavements, anti-erosion protection and strengthening of slopes, cones of bridges and overpasses , dams and banks of water bodies, the manufacture of geotubes as containers for dehydration and drying of various types of water-insoluble solids and industrial waste, the manufacture of geotubes for the construction of breakwaters, dams, breakwaters and artificial islands in hydraulic engineering, as protective shells for soil piles.

Prior Art

At present, the use of geotextiles in construction is widely known for its use, in particular, as drainage systems, reinforcing layers, geotubes.

Known reinforcing geocomposite material, including a cloth needle-punched non-woven material (geotextile) bonded to a polymer material, wherein the material contains the main layer of geotextile, on which a woven polymer material is applied by a needle-punched method, and in this form it has a water-permeable ability (see utility model patent RU 127382 U1, 04/27/2013).

A geoplatform is known for reinforcing a road embankment, containing geogrid modules fastened together, the cells of which are filled with filler and on top of which an additional layer of filler is located, the geogrid modules are placed on canvases of woven geotextile, while the geotextile canvases are located in the transverse direction relative to the axis of the roadway, and the edges of the canvases wrapped on each side on the surface of an additional layer of filler (see utility model patent RU 122100 Sh, 11/20/2012).

Known high-strength composite fabric for earthworks, containing the main layer of fabric in the form of woven geotextile, which is the top layer and non-woven material, which is the bottom layer. The described nonwoven web uses a needle punching technique to combine with each other with a woven geotextile, placing a plurality of nonwoven reinforcement materials on the described base fabric layer on the top surface. The lower surface of the fabric is covered with a thin layer of polyethylene films (see utility model patent CN 203331508 U,

A similar solution is known from a patent for a utility model of a composite subgrade, and contains a main layer of fabric in the form of a woven geotextile, which is the top layer and a non-woven material, which is the bottom layer. The described nonwoven web uses a needle punching technique to combine with each other with a woven geotextile, placing a plurality of nonwoven reinforcement materials on the described base fabric layer on the top surface. On the described main fabric layer of the upper surface, gaps are formed to accommodate a plurality of non-woven reinforcing materials, and the lower surface is provided with a thin layer of plastic foil.

A drainage geocomposite is known according to the utility model patent RU 98428 U1, 10/20/2010, containing a geogrid with a two-level structure for placing its elements forming cells, and two layers of geotextile, used as an alternative to traditional drainage systems made of crushed stone. This geocomposite, due to its low strength, does not provide a reinforcing function under conditions of high traffic loads during the construction of embankments on a weak foundation. As a result, construction in conditions of weak and waterlogged soils requires more material-intensive and labor-intensive ways to strengthen the base and ensure the operational reliability of road structures.

Known reinforcing geotextile material according to patent RU 127382 Sh, 04/27/2013, including a cloth of needle-punched non-woven material (geotextile) bonded to a polymer material, characterized in that it contains the main layer of geotextile, on which a woven polymer material is applied by a needle-punched method, and in such form is water permeable. The disadvantage of this technical solution is that the proposed material does not have reinforcing properties in soil structures under high loads for the following reasons: the connection of a woven polymer material is made by a needle-punched method, in which the threads of the woven structure are pierced with needles and its strength characteristics are significantly lost by 40-70%. ; with insufficient strength of the woven material and low resistance to mechanical damage under heavy load from the weight of an earth embankment constructed on a weak foundation, and under the influence of heavy road construction equipment, the material will deform with a loss of strength necessary to create a reinforcing effect. In addition, the woven polyester resin material is short-lived and decomposes under conditions of use in swamps and peat soils, which are characterized by an acidic environment (pH value 3, 0-5.0). To impart waterproofing properties to the reinforcing geocomposite, it is added from the side woven layer polymeric waterproof film with fixation by thermal bonding. In this case, the composite is subjected to heating, which can reduce its strength characteristics. The use of film materials for waterproofing requires the use of special protective technological layers to prevent damage by coarse inclusions along the contact boundary. For these reasons, the material cannot be used as a reinforcing layer for reinforcing road embankments built on weak, unstable, acidic bases subject to high loads, without a protective layer of fine sand.

This patent was chosen as the closest analogue. Known in construction, woven geotextiles and geocomposite materials based on them, when they perform the function of reinforcement, have low filtration and culvert capacity of the woven structure, which limits their scope and reduces the efficiency of geotextiles as part of drainage systems operating under pressure from the weight of road construction structures in ground layers and structural layers. Disclosure of invention

The technical problem to be solved by this solution is to increase the service life and operational reliability of road structures built on weak, waterlogged bases, as well as to reduce construction time and cost by reducing the consumption of building materials and pavement on the subgrade until its stabilization is completed. . The problem is solved due to the fact that the woven filter geotextile, according to the utility model, is made in the form of a fabric with a plain and twill weave of polypropylene threads with a melt flow rate of 3-5 g/10 min with the addition of an anti-fibrillation additive of calcium carbonate and a UV stabilizer, at the same time, threads with a linear density of 700-6000 denier and a width of 4-12 mm with a high degree of fibrillation were used for the weft, and flat threads with a linear density of 1000-4000 denier and a width of 1-4 mm were used for the warp, while the filtration coefficient of the geotextile is 40 m/day at a pressure of 100-200 kPa.

The edge of the geotextile is embedded, cut and melted by thermal or ultrasonic methods.

The geotextile edge is made of Leno type.

The type of threads on the warp is flat double or triple or quadruple. The technical result achieved by the claimed utility model is to increase the culvert capacity of the drainage system by 1.5 - 2.5 times, on which it is installed.

This technical result is provided by:

- improving the filtration of woven geotextiles from the value of the filtration coefficient (water permeability) of 10-20 m/day to the value of 40 m/day due to the type of polypropylene threads of flat double or triple or quadruple in warp and threads fibrillated in a special way in weft;

- increasing the service life of geotextiles by increasing resistance to UV radiation, chemical resistance in acidic and alkaline environments, frost resistance (the service life of geotextiles is at least 50 years with the provision of the required drainage properties in the structures used, taking into account a gradual decrease due to silting of the material with clayey particles).

The best example of the invention

Below will be presented a preferred embodiment of the invention, which, as it is clear to a person skilled in the art, does not limit other possible embodiments arising from the essence of this invention.

Geotextiles are made from polypropylene yarns on circular and flat weaving equipment of plain and twill weaving with different rapport. The threads are made of polypropylene with a melt flow index of 3-5 g/10 min with the addition of an anti-fibrillation additive of calcium carbonate and a UV stabilizer.

The choice of the melt flow index (MFR) is determined by the required viscosity of the thermoplastic. The greater the MFR of a thermoplastic, the lower its viscosity. Thus, this interval was chosen as optimal between high and low viscosity index.

Geotextile woven has a ratio of components u selected as follows: wt.%: p calcium narbonate of special grinding 2-8

UV stabilizer (Tosaf UV6639PP or Lightform 120601SB) 1-2 and As a UV stabilizer, for example, Tosaf is used

15 HV6639PP or Lightform 120601SB. UV stabilizers for

90 rollers are used to protect the surface from damaging light effects. Being under the sun's rays, polyethylene, polypropylene, PVC fade, turn yellow, paint. Cracks appear on the product, in which

20 moisture and dust penetrate. They are added to the original mixture or

95 are applied to the surface of the product. They include: hindered organic compounds, 2Q

35, which have a complex branched structure, slow down during

85 the movement of radicals, as well as antioxidants, which prevent the destruction of the material under the action of released oxygen. The use of light stabilizers allows you to absorb light, dissipating heat, slow down the processes of decomposition and react with already formed products. The service life of a high-quality UV stabilizer is up to 10 seasons. In this application, as examples, only trade names for the use of UV stabilizers are given without specific disclosure of their compositions, which are not the subject of protection, and with which field tests of the claimed coating were carried out. Weft geotextiles use threads with a high degree of fibrillation, for which the threads are passed through a rotating fibrillator with the following technological parameters: fibrillation frequency (number of needles) 7-10 needles/cm s pressing threads to the fibrillator shaft 30-45° r thread temperature 110-140°C o The linear weft density of the threads is 700-6000 denier with a width of 4-12 mm with a high degree of fibrillation. t On the base, flat threads with a linear density of 1000-4000 denier and a width of 1-4 mm were used.

The choice of density and width of the threads is due to the following factors. p Due to the fact that woven geotextiles are used in the structural layers of roads of all technical

S h e n categories, then to ensure its effective operation under load, certain strength requirements are imposed, which affects the density of the threads, namely:

I category of roads - 4000-6000 denier, II category - 3000-4000 denier, III category - 2000-3000 denier, IV-V - category 700-2000 denier.

Depending on this or that density, the width of the thread is selected. Thus, the density of the thread and its width are in direct proportion to each other, in accordance with the specific application of the geotextile.

The choice of weft thread width is based on experiments and is selected empirically, and which directly affects the strength and filtering ability of the geotextile as a whole. In this case, as is known to the specialist, due to the strength of the warp threads are thinner than the weft threads, which are thicker (wider). This explains the type of warp yarns, which is preferably triple twisted. However, in other embodiments, it can be a flat type of threads, as well as with a double or quarter twist of the threads.

The choice of a filtration coefficient of at least 40 m/day is explained by the practical advantages of geotextiles: the pace of construction of earth embankments on peat and waterlogged bases is increasing due to the acceleration of consolidation and stabilization processes, as well as a reduction in deadlines for the performance of works on dehydration and drying of various types of water-insoluble solids and industrial waste by increasing the filtration capacity of geotubes made of geotextiles by 30%. - reducing the deformation of pavement bases from frost heaving due to the prevention of excessive moisture;

- increasing the operational reliability of sections of the road in places where, during operation, it is possible to increase the moisture content of the subgrade or underlying soil with excess water from the waterlogged subgrade;

At the same time, for lower values of the filtration coefficient, these advantages are not provided. The pressure of 100-200 kPa is due to the fact that geotextiles can work in structures under high pressure due to the weight of road construction structures with a height of more than 5 m. At this pressure, various types of geotextiles are significantly compressed and reduce water transmission capacity, this explains a wide range of pressures.

To prove the achievement of the claimed technical result, a comparative analysis of the main indicators of geotextiles of the existing level of technology and according to the claimed solution was carried out, which is presented in Table 1: Table 1.

As follows from the above table, as well as the tests carried out, the claimed filtering geotextile with the above characteristics has, in comparison with the existing prior art, in addition to high reinforcing strength, the claimed increased drainage system culvert capacity by 1.5 - 2.5 times, which confirms the achievement of the claimed technical result

Industrial Applicability

The invention is applicable in the field of construction and can be used for the installation of drainage systems of various types, the installation of protective filtering and reinforcing layers in embankments on soft soils and in difficult soil and geological conditions and pavement bases, erosion protection and strengthening of slopes, cones of bridges and overpasses, dams and banks of reservoirs, production of geotubes as containers for dewatering and drying various types of water-insoluble solids and industrial waste, production of geotubes for the construction of piers, dams, breakwaters and artificial islands in hydraulic engineering construction, as protective shells for soil piles.

Claims

CLAIM

1. Woven filter geotextile, characterized in that it is made in the form of a fabric with plain and twill weave of polypropylene threads with a melt flow rate of 3-5 g / 10 min with the addition of an anti-fibrillation additive of calcium carbonate and a UV stabilizer, while weft threads are used with a linear density of 700-6000 denier and a width of 4-12 mm with a high degree of fibrillation, and flat threads with a linear density of 1000-4000 denier and a width of 1-4 mm are used on the base, while the geotextile filtration coefficient is 40 m / day at pressure 100-200 kPa.

2. Geotextile according to claim 1, characterized in that the edge of the geotextile is embedded, cut and melted by thermal or ultrasonic methods.

3. Geotextile according to claim 1, characterized in that the edge of the geotextile is made of the Leno type.

4. Geotextile according to claim 1, characterized in that the type of threads on the base is flat double or triple or quadruple.