A geogrid for cold regions and a method of using the same

Abstract

The application provides a geogrid for cold regions and a use method thereof, and belongs to the field of geogrids. A plurality of windows are arranged on a main body; a plurality of rib strips are arranged in the windows and intersect with each other; the main body is made of an elastic material and can be elastically deformed; two rib strips divide the window into two first cavities and two second cavities; a shape memory deformation piece is V-shaped and is arranged in the edge of the first cavity surrounded by the two rib strips; the two ends of the shape memory deformation piece extend away from the intersection part of the two rib strips; the shape memory deformation piece is contracted and deformed by cold and the interval between the two ends of the shape memory deformation piece in a preset direction is reduced; the shape memory deformation piece is contracted and deformed in a low-temperature environment, the width of the cavity is also contracted, a trend force of contraction in the preset direction is formed on the geogrid, the width of the window is reduced, the amount of soil protruding from the window and separating from the rock-soil body is reduced, and therefore, when the temperature is higher in the daytime, the reinforcing effect of the geogrid on the rock-soil body is avoided from being weakened.

Description

Technical Field

[0001] This invention relates to the field of geogrid technology, and in particular to a geogrid for use in cold regions and its application method. Background Technology

[0002] Geogrids are two-dimensional or three-dimensional mesh structures made of polymers such as polypropylene, polyvinyl chloride, and polyethylene through thermoplasticizing or molding. They possess unique properties and functions, and are commonly used as reinforcement materials in reinforced soil structures or composite materials. When applied in civil engineering construction, they are referred to as geogrids. Geogrids are typically applied to the construction surface to reinforce the soil and rock mass.

[0003] In cold regions, the moisture within soil and rock masses condenses into a solid state at night when ambient temperatures are low, and melts into a liquid state during the day when temperatures are higher. This causes significant differences in the volume of soil and rock masses due to diurnal temperature variations. Chinese patent CN213142696U discloses a novel cold-resistant steel-plastic geogrid. When soil and rock masses are exposed to higher daytime temperatures, the geogrid effectively reinforces them, tightly and firmly covering the soil and rock mass. However, when the soil and rock masses are exposed to lower nighttime temperatures, the condensation of moisture within them causes the soil and rock mass to increase in volume. The geogrid, on the other hand, shrinks due to the cold, causing the soil and rock to expand the mesh openings on the geogrid. Some soil or rocks may protrude from these enlarged mesh openings and detach from the soil and rock mass. Consequently, when the soil and rock masses are exposed to higher daytime temperatures again, the geogrid struggles to hold the soil and rock firmly, thus weakening its reinforcing effect. Summary of the Invention

[0004] In view of this, the present invention proposes a geogrid for cold regions and its application method, which is used to solve the problem that when the soil and rock are in a low-temperature environment at night, the water in the soil and rock condenses into solids, which increases the volume of the soil and rock. The geogrid will shrink to a certain extent when it is cooled, which causes the soil and rock to expand the mesh windows on the geogrid. Some soil will bulge out of the enlarged mesh windows on the geogrid and detach from the soil and rock.

[0005] The technical solution of this invention is implemented as follows: This invention provides a geogrid for cold regions, comprising a main body with a plurality of windows arranged along a predetermined direction; a plurality of ribs, intersecting in pairs and disposed within the windows; and a shape memory deformable element; wherein, the main body is made of an elastic material and is capable of elastic deformation; two ribs divide the windows into two first cavities and two second cavities, the two first cavities being located on both sides of the predetermined direction, and the two second cavities being arranged along the predetermined direction and located between the two first cavities, the two ribs forming a V-shape around the edge of the first cavity; the shape memory deformable element is V-shaped and passes through the edge of the first cavity surrounded by the two ribs, the two ends of the shape memory deformable element extending away from the intersection of the two ribs, the shape memory deformable element shrinking and deforming when cooled, reducing the distance between its two ends along the predetermined direction.

[0006] Based on the above technical solution, preferably, two ribs are provided with a first flange around the edge of the first cavity. The first flange is V-shaped and protrudes outward along the vertical direction of the main body surface. The shape memory deformation component is inserted in the first flange. The shape memory deformation component is cooled and deformed, which drives the first flange to deform synchronously.

[0007] More preferably, the two ribs are provided with a second flange around the edge of the second cavity, and the second flange is V-shaped; the shape memory deformation component is cooled and deformed, and drives the second flange to deform at the same time, so that the distance between the two ends of the second flange increases.

[0008] More preferably, the width of the rib along its extension direction is 2mm-4mm, the width of the first flange along its extension direction is not greater than 0.5mm, and the thickness of the shape memory deformation part is not greater than 0.3mm.

[0009] The surfaces at the intersection of the two ribs are provided with protrusions that can be cooled and expanded.

[0010] More preferably, the protrusion is hemispherical, and the diameter of the sphere in the expanded state is not less than 1 cm.

[0011] More preferably, the protrusion has a receiving cavity, which is filled with silicone rubber material.

[0012] Even more preferably, the main body is made of high-density polyethylene material through an extrusion punching and integral stretching process.

[0013] Based on the above technical solutions, preferably, the length of the window along the preset direction is 3cm-5cm, and the width of the window along the preset direction is 40cm-50cm.

[0014] Based on the above technical solutions, preferably, the length of the first cavity extending vertically along the preset direction is 18cm-20cm.

[0015] On the other hand, the present invention also provides a method for using geogrid in cold regions. The method using the geogrid for cold regions includes the following steps: Step 1, when the ambient temperature is above zero degrees Celsius, the geogrid is covered on the construction surface; Step 2, when the ambient temperature drops below zero degrees Celsius and reaches a temperature that causes the shape memory deformation element to deform, the shape memory deformation element shrinks and deforms due to the cold, and the distance between the two ends of the V-shape decreases, causing the length of the window to decrease along a preset direction; Step 3, the protrusion expands and deforms due to the cold, increasing the depth of the protrusion embedded in the construction surface.

[0016] The geogrid for cold regions and its application method of the present invention have the following advantages over the prior art:

[0017] (1) The present invention sets a shape memory deformation type on the edge of the V-shaped cavity formed by the intersection of two ribs, so that it shrinks and deforms in a low temperature environment, and the width of the cavity also shrinks accordingly, thereby forming a tendency force of shrinkage in a preset direction on the geogrid, reducing the width of the window, reducing the amount of soil protruding from the window and detaching from the rock and soil, so as to avoid weakening the reinforcement effect of the geogrid on the rock and soil when the daytime temperature returns to a higher temperature.

[0018] (2) The present invention provides a protrusion on the surface of the intersection of the ribs that can expand as the temperature decreases, so that the protrusion can increase the depth of embedding into the rock and soil when the ambient temperature drops, thereby forming a more favorable solidification potential for the rock and soil.

[0019] (3) In this invention, the grid body is first obtained by extrusion punching and overall stretching process, and then the shape memory deformation component is inserted into the flange surrounding the cavity. A receiving cavity is opened in the protrusion to accommodate the material that expands and deforms due to cold. The manufacturing difficulty is not very high, so it is suitable for mass production. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a perspective view of the geogrid of the present invention;

[0022] Figure 2 This is a front view of the geogrid of the present invention;

[0023] Figure 3 This is a perspective view of another embodiment of the geogrid of the present invention;

[0024] Figure 4 This is a front view of another embodiment of the geogrid of the present invention;

[0025] Figure 5 This is a front view of the geogrid of the present invention in its contracted state.

[0026] Figure 6 This is a cross-sectional view of the geogrid of the present invention along line AA;

[0027] Figure 7 For the present invention Figure 6 Enlarged view of point A in the middle.

[0028] In the figure: 1. Main body; 11. Protrusion; 100. Window; 101. First cavity; 102. Second cavity; 2. Rib; 21. First flange; 22. Second flange; 3. Shape memory deformation component. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figure 1 As shown, combined with Figure 3 , Figure 5 and Figure 6 The present invention provides a geogrid for cold regions, comprising a main body 1, ribs 2 and shape memory deformation elements 3.

[0031] The main body 1 has several windows 100 arranged along a predetermined direction. The main body 1 is the main part of the grille, and therefore a mesh structure is formed by several intersecting strips, with the mesh openings being the windows 100. The main body 1 is made of an elastic material and is capable of elastic deformation.

[0032] The geogrid of this invention mainly relates to unidirectional geogrids, which are primarily used in the construction of road slopes or building walls. Therefore, during implementation, they are mainly subjected to unidirectional vertical tensile forces. Consequently, the windows 100 of this type of geogrid are elongated strips, which causes the expansion of the soil and rock mass to enlarge the windows 100, leading to the detachment of stones or soil within them. Currently, two main methods are used to address the problem of the expanded windows 100 of the geogrid: First, the length of the windows 100 along a predetermined direction is reduced to make the windows 100 more densely arranged, but this method does not fundamentally counteract the expanding force on the windows 100; second, multiple transverse reinforcing ribs are set inside the windows 100. However, due to the different soil-to-stone ratios in different soil masses, fewer transverse reinforcing ribs can be set for fill materials with more stones and less soil, while more transverse reinforcing ribs are needed for fill materials with less stones and more soil, significantly increasing production costs.

[0033] Several ribs 2 are intersected in pairs and arranged within the window 100. Compared to horizontal ribs, the intersecting ribs 2 can prevent a larger area of ​​rock and soil from detaching from the window 100. Even if multiple sets of intersecting ribs 2 need to be arranged, the number of ribs 2 required will be less than that required for horizontal ribs. For each window 100, the two ribs 2 divide the window 100 into two first cavities 101 and two second cavities 102, for example... Figure 1 The window 100 is hexagonal in shape, with its top and bottom ends being the two furthest corners of the hexagon. When the mechanism formed by the intersection of the two ribs 2 divides the window 100 into four cavities, the two ribs 2 form a V-shape around the edge of the first cavity 101. The two first cavities 101 are located on both sides of a preset direction, so the shape of the first cavity 101 is similar to a rhombus. The two second cavities 102 are arranged along a preset direction and located between the two first cavities 101. The shape of the second cavity 102 is similar to a triangle.

[0034] The shape memory deformable element 3 is V-shaped and passes through the two ribs 2 around the edge of the first cavity 101. The bottom of the V-shape of the shape memory deformable element 3 is rounded. The two ends of the shape memory deformable element 3 extend away from the intersection of the two ribs 2. Therefore, the shape memory deformable element 3 does not surround the entire edge of the first cavity 101, but is only set on the edge of the first cavity 101 surrounded by the two ribs 2.

[0035] The shape memory deformable part 3 shrinks and deforms upon cooling, reducing the distance between its two ends along a predetermined direction. Modern research has found that some metallic materials, after undergoing significant plastic deformation, will extend back to their original shape upon heating, and then shrink and deform upon cooling. The same material, within a certain temperature range, can exhibit strains up to 10%, and will still return to its original shape upon unloading. These unusual effects are respectively called thermal shape memory and superelasticity (elastic shape memory). Both effects depend on the occurrence of a specific type of phase transformation, called thermoelastic martensitic transformation. The shape memory deformable part 3 of this invention is made of such a metal, generally a nickel-titanium based alloy, such as titanium-nickel alloy, titanium-nickel-niobium alloy, titanium-nickel-palladium alloy, etc., and of course, copper-based alloys or iron-based alloys can also be used. Specifically, its material composition is nickel, titanium, and copper, with the mass percentages of nickel, titanium, and copper being Ni 48.0-51.0%, Ti 43.5-47.5%, and Cu 4.5-5.5%.

[0036] In this invention, the shape memory deformation element 3 is inserted within the edge of the first cavity 101 surrounded by two ribs 2. Therefore, when the ambient temperature drops significantly until it reaches the critical temperature at which the shape memory deformation element 3 deforms, the shape memory deformation element 3 contracts due to the cold: on the one hand, the length of the two sides of the V-shape of the shape memory deformation element 3 shrinks, causing the length of the first cavity 101 in the vertical direction along the preset direction to decrease accordingly; on the other hand, the included angle at the bottom of the V-shape of the shape memory deformation element 3 also decreases, causing the distance between the two ends of the top of the V-shape to decrease accordingly, thereby reducing the length of the first cavity 101 in the preset direction. Through the shrinkage deformation of the shape memory deformation element 3, the length and width of the first cavity 101 shrink, thus reducing the area of ​​the first cavity 101; and since the main body 1 of the geogrid has a mesh structure, it can be regarded as the geogrid undergoing tightening deformation in a low-temperature environment, thereby allowing the geogrid to use the shrinkage trend to offset the expansion trend of the geogrid caused by the increase of the rock and soil mass, thus avoiding the situation where the geogrid and the window 100 on it are expanded by the increased rock and soil mass due to the cold. It should be noted that in actual use, the shrinkage deformation of the shape memory deformation component 3 will provide a shrinkage tendency to the main body 1, thereby offsetting the expansion tendency of the geogrid caused by the increase of the soil mass, rather than actually causing the main body 1 to undergo obvious dimensional changes.

[0037] exist Figure 2In a preferred embodiment shown, the main body 1 is typically made of a non-metallic material with elastic deformation capability, while the shape memory deformable element 3 is made of a shape memory alloy material. Therefore, in order to install the shape memory deformable element 3 inside the main body 1, two ribs 2 are provided with a first flange 21 around the edge of the first cavity 101. The first flange 21 is V-shaped and protrudes outward in the vertical direction along the surface of the main body 1. The first flange 21 has a larger width and thickness than the ribs 2. The shape memory deformable element 3 is inserted into the first flange 21, allowing for the use of a shape memory deformable element 3 with a larger width and thickness. This enables the shape memory deformable element 3 to generate a greater tendency force during deformation, causing the shape memory deformable element 3 to deform under cold and drive the first flange 21 to deform synchronously. Consequently, the area of ​​the window 100 is reduced, preventing the soil and rock mass from expanding the window 100. The first flange 21 can also be embedded in the soil and rock mass to improve the reinforcement effect between the main body 1 and the soil and rock mass.

[0038] exist Figure 7 In a preferred embodiment shown, to further improve the reinforcement effect of the grid on the soil and rock mass, two ribs 2 are provided with a second flange 22 around the edge of the second cavity 102. The second flange 22 is V-shaped. The shape memory deformation element 3 deforms under cold and drives the second flange 22 to deform simultaneously, increasing the distance between the two ends of the second flange 22. The second flange 22 is also embedded into the soil and rock mass. The second flange 22 and the first flange 21 are provided on both sides of the rib 2 along the extension direction of the rib 2. Therefore, the second flange 22 and the first flange 21 are embedded into and clamp the soil mass simultaneously, further improving the reinforcement effect of the grid on the soil and rock mass.

[0039] exist Figure 4In a preferred embodiment shown, the main body 1 is typically 1M*75M or 1M*100M in size. Connecting joints are provided on the upper and lower sides of the main body 1, and adjacent main bodies 1 are connected via these joints to form a complete grid structure. For example, in this invention, the width of the main body 1 (i.e., its length in the vertical direction along a predetermined direction) is 1M, the width of the horizontal ribs is ≥16mm, the width of the vertical ribs is ≥4mm, the width of the ribs 2 along their extension direction is 2mm-4mm, and the thickness of the ribs 2 is 0.5mm. This reduces production costs while ensuring the tensile strength of the ribs 2. The window 100 is elongated along its width direction, with the length of the window 100 along its width direction as its long side and the length of the window 100 along a predetermined direction as its wide side. The wide side of the window 100 is extremely narrow while its long side is very long, compared to common... The window 100 of this invention, formed by a geogrid with similar length and width dimensions, has a more flexible deformation space. This is because when a geogrid window with similar length and width dimensions deforms under an outward expanding force, the deformation of each side is relatively large. However, because the window 100 of this invention has a narrower wide side, its long side is subjected to a greater expanding force and thus has a larger deformation. Compared to the width, it is affected by a smaller expanding force and has a smaller deformation. This ensures that the deformation of the wide side of the window 100 is less severe when it deforms, thus maintaining the reinforcement effect on the soil and rock mass. In addition, the width of the first flange 21 along its extension direction is no more than 0.5 mm, and the thickness of the shape memory deformation member 3 is no more than 0.3 mm. This gives the shape memory deformation member 3 a larger width and thickness, allowing it to generate a larger expanding force to counteract the expanding force of the soil and rock mass that causes the window 100 to expand.

[0040] exist Figure 4 In a preferred embodiment shown, in order to further enhance the reinforcement effect of the grid on the soil and rock, a protrusion 11 is provided on the surface of the intersection of the two ribs 2. The protrusion 11 can be embedded into the soil and rock. At the same time, the protrusion 11 can be cooled and expanded, so that the volume of the protrusion 11 expands in the low temperature environment, thereby increasing the embedding depth of the protrusion 11 into the soil and rock, thereby improving the reinforcement performance of the grid on the soil and rock.

[0041] exist Figure 4 In a preferred embodiment shown, the protrusion 11 is hemispherical, or it can be the shape of half a pulley; specifically, the diameter of the sphere of the protrusion 11 in the expanded state is not less than 1 cm, so as to ensure the reinforcement effect of the protrusion 11 embedded in the rock and soil.

[0042] exist Figure 4In a preferred embodiment shown, during the production of the grid, a receiving cavity is formed within the protrusion 11, and the receiving cavity is filled with silicone rubber material. Silicone rubber is a negative thermal expansion material, which has been researched and applied in various fields in recent years. When the temperature rises, silicone rubber molecules become more active due to thermal motion, resulting in a reduction in the volume of the silicone rubber; when the temperature drops, silicone rubber molecules become less active or even solidify due to reduced thermal motion, resulting in an expansion in the volume of the silicone rubber. Since this invention aims to utilize the property of negative thermal expansion materials expanding upon cooling, rather than studying the formulation and deformation mechanism of negative thermal expansion materials, the specific components and formulation of the silicone rubber material are not described in detail.

[0043] exist Figure 1 In a preferred embodiment shown, the main body 1 is made of high-density polyethylene material through an extrusion, punching, and integral stretching process. High-density polyethylene (HDPE) is used as the raw material in its preparation, with a minimum carbon black content ≥2% and an inorganic impurity content ≤0.5%, and a density ≥0.94 g / cm³. 2 The specific process of preparation using the extrusion punching integral stretching process is as follows: 1) High-density polyethylene raw material is melted and injected into the extrusion mold for extrusion; 2) The structure of the main body 1 of the grid is formed by stretching; 3) The first cavity 101 and the second cavity 102 are formed by punching holes in the main body 1; 4) The first flange 21 and the second flange 22 are formed on the ribs by stamping; 5) A channel for accommodating the shape memory deformation component 3 is opened on the first flange 21, and a receiving cavity is opened at the intersection of the two ribs 2 to inject silicone rubber material.

[0044] exist Figure 1 In a preferred embodiment shown, specifically, the length of the window 100 along the preset direction is 3cm-5cm, and the width of the window 100 along the preset direction is 40cm-50cm; the length of the first cavity 101 extending vertically along the preset direction is 18cm-20cm, thereby making the window 100 form a structure with an extremely narrow wide side and a very long long side, thus giving the window 100 more flexible deformation space.

[0045] like Figure 1 As shown, combined with Figure 5 The present invention provides a method for using geogrids for cold regions, employing geogrids for cold regions according to any of the above embodiments, and includes the following steps.

[0046] Step 1: When the ambient temperature is above zero degrees Celsius, cover the construction surface with geogrid.

[0047] Step 2: When the ambient temperature drops below zero and reaches the temperature that causes the shape memory deformable part 3 to deform, the shape memory deformable part 3 shrinks and deforms due to the cold, and the distance between the two ends of the V-shape decreases, causing the length of the window 100 to decrease along the preset direction.

[0048] Step 3: The protrusion 11 expands and deforms when cooled, increasing the depth at which the protrusion 11 is embedded in the construction surface.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A geogrid for use in cold regions, characterized in that, include: The main body (1) has several windows (100) arranged along a predetermined direction; Several ribs (2) intersect each other in pairs and are arranged within the window (100); Shape memory deformable parts (3); The main body (1) is made of an elastic material and is capable of elastic deformation; The two ribs (2) divide the window (100) into two first cavities (101) and two second cavities (102). The two first cavities (101) are located on both sides of a preset direction, and the two second cavities (102) are arranged along the preset direction and located between the two first cavities (101). The two ribs (2) form a V-shape around the edge of the first cavity (101). The shape memory deformable element (3) is V-shaped and passes through the two ribs (2) around the edge of the first cavity (101). The two ends of the shape memory deformable element (3) extend away from the intersection of the two ribs (2). The shape memory deformable element (3) shrinks and deforms when cooled, and the distance between its two ends decreases along a preset direction.

2. A geogrid for cold regions according to claim 1, characterized in that: Two ribs (2) are provided with a first flange (21) around the edge of the first cavity (101). The first flange (21) is V-shaped and protrudes outward along the vertical direction of the surface of the main body (1). The shape memory deformation element (3) is inserted in the first flange (21). The shape memory deformation element (3) is cooled and deformed, driving the first flange (21) to deform synchronously.

3. A geogrid for cold regions according to claim 2, characterized in that: The two ribs (2) are provided with a second flange (22) around the edge of the second cavity (102), and the second flange (22) is V-shaped; the shape memory deformation member (3) is cooled and deformed, and drives the second flange (22) to deform at the same time, so that the distance between the two ends of the second flange (22) increases.

4. A geogrid for cold regions according to claim 2, characterized in that: The rib (2) has a width of 2mm-4mm along its extension direction, the first flange (21) has a width of no more than 0.5mm along its extension direction, and the shape memory deformable part (3) has a thickness of no more than 0.3mm.

5. A geogrid for cold regions according to claim 1, characterized in that: A protrusion (11) is provided on the surface of the intersection of the two ribs (2), and the protrusion (11) can be cooled and expanded.

6. A geogrid for cold regions according to claim 5, characterized in that: The protrusion (11) is hemispherical, and the diameter of the protrusion (11) in the expanded state is not less than 1 cm.

7. A geogrid for cold regions according to claim 5, characterized in that: The protrusion (11) has a receiving cavity, which is filled with silicone rubber material.

8. A geogrid for cold regions according to claim 7, characterized in that: The main body (1) is made of high-density polyethylene material through an integral stretching process of extrusion punching.

9. A geogrid for cold regions according to claim 1, characterized in that: The length of the window (100) along the preset direction is 3cm-5cm, and the width of the window (100) along the preset direction is 40cm-50cm. The length of the first cavity (101) extending vertically along the preset direction is 18cm-20cm.

10. A method of using geogrids in cold regions, characterized in that: The method of using the geogrid for cold regions according to any one of claims 5 to 8 includes the following steps: Step 1: When the ambient temperature is above zero degrees Celsius, cover the construction surface with the geogrid; Step 2: When the ambient temperature drops below zero and reaches the temperature that will cause the shape memory deformation component (3) to deform, the shape memory deformation component (3) shrinks and deforms due to the cold, and the distance between the two ends of the V-shape is reduced, which drives the window (100) to shrink in length along the preset direction. Step 3: The protrusion (11) expands and deforms when cooled, increasing the depth at which the protrusion (11) is embedded in the construction surface.

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