Geogrid for foundation pit supporting and construction method

Abstract

The invention relates to the technical field of foundation pit supporting, and discloses a geogrid for foundation pit supporting and a construction method.The geogrid comprises a grid body which is provided with a first surface and a second surface which are opposite; the geomembrane is arranged on the first surface of the grille body; the reinforcing parts are arranged on the second surface of the grille body, and continuous wave crests and wave troughs are formed on the end faces, away from the grille body, of the reinforcing parts; a plurality of anchor rods are constructed in a foundation pit, a plurality of geogrids are hung on the plurality of anchor rods, and the plurality of geogrids are sequentially overlapped through wave crests and wave troughs, so that the problems of stress concentration, poor combinability with a soil body, complex construction, insufficient durability and the like in a traditional supporting scheme are solved; therefore, the stability and the deformation resistance of the support are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit support, and particularly to a geogrid for foundation pit support and a construction method thereof. Background Art

[0002] In engineering construction, foundation pit support is a key link to ensure construction safety and project quality. Traditional support structures usually adopt methods such as steel mesh and concrete spraying, but these methods have certain limitations, such as complex construction, high cost, and insufficient environmental adaptability. In addition, when facing complex geological conditions, traditional support structures are prone to problems such as local stress concentration and soil deformation, resulting in settlement and displacement of the foundation pit slope. Summary of the Invention

[0003] The purpose of the present invention is to provide a geogrid for foundation pit support and a construction method thereof, which solve the problems of stress concentration, poor bonding with soil, complex construction, and insufficient durability in traditional support schemes, thereby improving the stability and anti-deformation ability of the support.

[0004] To achieve the above object, the present invention provides the following solution: The present invention provides a geogrid for foundation pit support, including:

[0005] A grid body having opposite first and second surfaces;

[0006] A geomembrane disposed on the first surface of the grid body;

[0007] A plurality of sections of strengthening parts disposed on the second surface of the grid body, and continuous wave peaks and wave valleys are formed on the end surface of the strengthening part away from the grid body.

[0008] Optionally, the strengthening part includes a plurality of corrugated blocks arranged in parallel, and the wave peaks and wave valleys are formed between two adjacent corrugated blocks.

[0009] Optionally, the corrugated block is one of V-shaped, U-shaped, and UV-shaped.

[0010] Optionally, the grid body includes a plurality of grid bars arranged alternately in the horizontal and vertical directions, the grid bars have the first surface and the second surface, and the strengthening part is disposed on the second surface of each grid bar.

[0011] Optionally, a rectangular strip is disposed on the first surface of the grid bar.

[0012] Optionally, the thickness of the rectangular strip is 1-2 mm and the width is 3-5 mm.

[0013] Optionally, the height difference between the wave peak and the wave valley is 3-5 mm.

[0014] Optionally, the geomembrane is made of high-density polyethylene.

[0015] The present invention also provides a construction method for foundation pit support, including:

[0016] Performing a number of anchor rod constructions in the foundation pit;

[0017] Hanging a number of the geogrids on a number of the anchor rods.

[0018] Optionally, the step of hanging a number of the geogrids on a number of the anchor rods includes:

[0019] A number of the geogrids are overlapped in sequence through the wave crests and wave troughs.

[0020] The present invention discloses the following technical effects:

[0021] 1. By arranging a number of reinforcing portions on the grid body and setting the end faces of the reinforcing portions as continuous wave crest and wave trough structures, the compressive strength and anti-deformation ability of the geogrid are effectively improved, so that the grid can better disperse stress when subjected to external forces, reduce local stress concentration, can effectively restrain soil deformation, reduce the settlement and displacement of the foundation pit slope, enhance the support stability, and by arranging the geomembrane, the friction between the geogrid and the soil is increased, further enhancing the support stability, enabling it to adapt to complex geological conditions and construction environments.

[0022] 2. The geogrid of the present invention can replace the steel mesh in the traditional construction of shotcreting with wire mesh on the foundation pit slope, simplify the construction process, and can realize the reuse of materials when used for temporary support structures, reducing the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0024] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 is a schematic diagram of the grid body structure of the present invention;

[0026] Figure 3 is a schematic diagram of the overlap of three geogrids of the present invention;

[0027] Figure 4 is a schematic diagram of the overlap and engagement of the wave crest and wave trough of the present invention.

[0028] In the figure: 1, grid body; 2, geomembrane; 3, reinforcing portion; 4, rectangular strip. Detailed implementation manners

[0029] Traditional foundation pit support structures usually use steel wire cages in combination with concrete pouring. First, according to the design requirements, appropriate high-strength steel bars (such as HRB400 or HRB500 grade) are selected. With the help of an excavator or a crane, the welded steel wire cage is placed into the reserved foundation pit to ensure the correct position. Support struts are used to fix the position of the steel wire cage and strengthen the connection with the concrete pile. Ensure that the steel wire cage fits tightly against the foundation pit wall to avoid voids. Concrete is poured into the steel wire cage until the entire foundation pit is filled, and vibration is carried out to ensure that the concrete completely fills every void. After the concrete reaches the predetermined strength, the support struts are removed, and the steel wire cage can play its supporting and strengthening roles. There are problems such as complex construction, high cost, and insufficient environmental adaptability. In addition, when facing complex geological conditions, problems such as local stress concentration and soil deformation are likely to occur, resulting in settlement and displacement of the foundation pit slope.

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0032] Referring to Figures 1 - 4 , the present invention provides a geogrid for foundation pit support, including:

[0033] A grid body 1 having opposite first and second surfaces;

[0034] A geomembrane 2 disposed on the first surface of the grid body;

[0035] A plurality of sections of reinforcing portions 3 are disposed on the second surface of the grid body 1, and continuous wave peaks and wave valleys are formed on the end surface of the reinforcing portion 3 away from the grid body 1.

[0036] By providing a plurality of sections of reinforcing portions 3 on the grid body 1 and setting the end surface of the reinforcing portion 3 as a continuous wave peak and wave valley structure, the compressive strength and anti-deformation ability of the geogrid are effectively improved, so that the grid can better disperse stress when subjected to external forces, reduce local stress concentration, can effectively restrain soil deformation, reduce the settlement and displacement of the foundation pit slope, and enhance the support stability. And by providing the geomembrane 2, the friction between the geogrid and the soil is increased, further enhancing the support stability, enabling it to adapt to complex geological conditions and construction environments.

[0037] The high tensile strength and low elongation characteristics of the geogrid of the present invention enable it to effectively reduce the generation of cracks in foundation pit support.

[0038] In an embodiment of the present invention, the strengthening portion 3 includes a plurality of corrugated blocks arranged in parallel. A wave crest and a wave trough are formed between adjacent corrugated blocks. The height difference between the wave crest and the wave trough is 3 - 5 mm. The corrugated block is one of V-shaped, U-shaped, and UV-shaped. In this embodiment, the corrugated block is exemplified as V-shaped.

[0039] By setting the corrugated blocks, the flexibility and compressive strength of the geogrid are increased. This design can significantly improve the compressive strength and anti-deformation ability of the geogrid, effectively disperse stress, and reduce local stress concentration.

[0040] U-shaped corrugated block: The U-shaped corrugated block has a relatively large arc radius, has good buffering performance and elasticity, and can return to its original state when the pressure is removed. However, its compressive resistance is weak and the cost is high.

[0041] V-shaped corrugated block: The V-shaped corrugated block has a relatively small arc radius, strong compressive resistance, and low cost.

[0042] UV-shaped corrugated block: The UV-shaped corrugated block is a shape between U-shaped and V-shaped, with an arc radius larger than that of the V-shaped but smaller than that of the U-shaped, and has the advantages of both.

[0043] In an embodiment of the present invention, the grid body 1 includes a plurality of grid bars arranged alternately horizontally and vertically. The grid bars have a first surface and a second surface, and a strengthening portion 3 is provided on the second surface of each grid bar.

[0044] The mesh structure of the grid body formed by a plurality of grid bars arranged alternately horizontally and vertically can form a good interlocking effect with the soil body, enhancing the bearing capacity of the soil body.

[0045] Several corrugated blocks are combined with grid bars to form corrugated grid bars. The several corrugated blocks form a shape similar to a wave shape, which has high compressive strength and flexural stiffness. When this structure is subjected to external forces, it can disperse the forces along the curved surface of the waveform instead of concentrating at a certain point. When the grid bars are subjected to external forces, the stress will be evenly distributed along the undulations of the waveform. This uniform stress distribution can effectively avoid stress concentration phenomena, thereby reducing the risk of local damage. It can better adapt to complex stress environments, especially in foundation pit support, and can effectively disperse the pressure of the soil on the side wall of the foundation pit. The corrugated grid bars have high flexural stiffness and can maintain good shape stability when subjected to external forces. It can not only effectively disperse stress, but also restrain the deformation of the soil to a certain extent, reducing the settlement and displacement of the foundation pit slope. Compared with flat grid bars, the corrugated grid bars have a smaller deformation degree when subjected to the same external force. The corrugated grid bars have a larger contact area with the soil and can provide greater friction. This increased friction helps to further enhance the overall stability.

[0046] Furthermore, both the corrugated blocks and the grid bars are made of high-strength polypropylene materials and are formed by stretching through a special process to ensure their high strength and durability.

[0047] In an embodiment of the present invention, a rectangular strip 4 is provided on the first surface of the grid bar.

[0048] The rectangular strip 4 not only provides an additional protective layer but also enhances the integrity of the geogrid.

[0049] Furthermore, the rectangular strip 4 is made of high-strength polypropylene material and has good weather resistance and anti-aging performance.

[0050] The grid bars and the rectangular strip 4 made of high-strength polypropylene material can ensure the high strength and durability of the geogrid.

[0051] In an embodiment of the present invention, the thickness of the rectangular strip 4 is 1 - 2 mm and the width is 3 - 5 mm, which is adaptively adjusted according to the size and application requirements of the geogrid.

[0052] In an embodiment of the present invention, the geomembrane 2 is made of high-density polyethylene material, which has high strength, strong corrosion resistance, high tensile strength, low elongation rate, and good tear resistance. The high-density polyethylene material is a non-toxic and environmentally friendly material that meets environmental protection requirements. The geomembrane 2 can further enhance its anti-seepage and protection functions, increase the friction between the geogrid and the soil, and at the same time can effectively restrain the deformation of the soil, reducing the settlement and displacement of the foundation pit slope.

[0053] Furthermore, the grille bars, rectangular bars 4, and geomembrane 2 are all bonded together using high-performance adhesives to ensure a tight bond and prevent separation during use, even under complex geological conditions and adverse environmental impacts. The adhesives used are one or more of polyurethane glue, epoxy resin, asphalt, and modified asphalt, which have good bonding strength and durability.

[0054] In the traditional construction of shotcrete with wire mesh on the foundation pit slope, the geogrid of this application can be used instead of the wire mesh. Its high tensile strength and good durability can effectively improve the bearing capacity of the support structure, while reducing the construction difficulty and cost. The product is convenient for construction, and during laying, it is necessary to ensure that it is flat and firmly fixed. Its good durability and anti-aging performance enable it to adapt to complex geological environments and long-term use requirements.

[0055] This application is applicable to the temporary or permanent support of foundation pit projects, can effectively support the side wall of the foundation pit to prevent soil collapse, and can also be used for the reinforcement of the foundation pit slope to prevent slope sliding and soil erosion.

[0056] The present invention also provides a construction method for foundation pit support, including:

[0057] Carefully study the design drawings to understand technical parameters such as the slope gradient, height, thickness, and strength grade of the wire mesh and shotcrete of the slope. According to the design requirements and the actual site conditions, prepare a detailed construction plan, including construction technology, construction progress plan, quality control measures, safety measures, etc. Prepare geogrid materials, anchor bolts, cement, sand, stones, and other materials as well as construction equipment according to the design requirements. Before construction, remove the floating soil, loose stones, sundries, etc. on the slope surface to ensure that the slope surface is flat and clean. According to the slope height and construction needs, set up a scaffolding or construction platform to ensure the safety of construction personnel and the convenience of construction operations.

[0058] Conduct several anchor bolt constructions in the foundation pit. The basic sequence of anchor bolt construction is positioning, hole forming, grouting, and setting the anchor bolt. Drill and install the anchor bolts according to the design requirements. The spacing, length, and angle of the anchor bolts should meet the design requirements;

[0059] Hang several geogrids on several anchor bolts. After the strength of the fixing mortar of the anchor bolts reaches 70% of the design value, hang the geogrids on the anchor bolts and fix them with iron wires to ensure that the direction of the corrugated grille bars is consistent with the stress direction. During laying, it should be kept flat and taut to avoid wrinkles and twists. Cover the grille body with the geomembrane 2 and fix it with an adhesive to prevent separation.

[0060] After the laying is completed, shotcrete or other support constructions can be carried out as needed. During the construction process, damage to the grille body and the geomembrane 2 should be avoided.

[0061] If shotcrete is used, control marks for the thickness of the shotcrete shall be set in advance to ensure the thickness of the shotcrete. The spraying operation shall be carried out in sections, slices and layers, in sequence from bottom to top, and from left to right or from right to left successively according to the terrain conditions and wind direction.

[0062] When starting to spray, the distance between the nozzle and the sprayed surface shall be reduced and the spraying angle shall be adjusted; the water-cement ratio shall be well controlled to keep the concrete surface flat, moist and shiny, without dry patches or sliding and flowing phenomena; during spraying, the nozzle shall be perpendicular to the slope surface, and an appropriate distance and pressure shall be maintained.

[0063] After the concrete begins to set, watering curing shall be carried out at normal temperature, not less than 3 times a day. The curing time is generally 5 - 7d. During the curing process, if any adverse phenomena such as spalling, bulging, cracking, local wetness, uneven color, etc. are found, the reasons shall be analyzed and remedial measures shall be taken.

[0064] The geogrid and the anchor head shall not be exposed, and the connection and sealing treatment between the sprayed layer and the unprotected slope surface shall be well done to prevent water from invading through the gaps; spraying operations shall not be carried out in rainy, snowy, windy weather and when the temperature is below 0°C.

[0065] In an embodiment of the present invention, hanging a plurality of geogrids on a plurality of anchor bolts includes:

[0066] A plurality of geogrids are overlapped in sequence through crests and troughs, as shown in Figure 4 , and a 10 - 20 cm geogrid is overlapped on two geogrids and the three are fixed with U-shaped nails or steel nails to ensure its stability.

[0067] In the construction plan of shotcreting with wire mesh on the traditional foundation pit slope, the present invention can use geogrids instead of wire meshes. Its use in the project can reduce the dependence on traditional high-energy-consuming materials (such as steel bars). It not only simplifies the construction process, reduces the construction difficulty, but also reduces the material cost, with significant economic benefits. The laying of the grid body and the geomembrane 2 is relatively simple, the construction speed is fast, and the requirements for construction equipment are low. This construction method is especially suitable for complex environments such as foundation pits and can effectively shorten the construction period.

[0068] After the project is completed, the geogrids of the present invention can be removed and reprocessed for the production of new geogrids or other plastic products. This recyclability reduces the dependence on natural resources and at the same time reduces the generation of waste. Geogrids have a long service life and high durability. This means that during use, it requires less maintenance and replacement frequency, thus reducing resource waste and environmental impact. During the production process, waste plastics and recycled fibers can be used as raw materials for geogrids. This reuse of resources not only reduces the generation of waste, but also reduces carbon emissions during the production process.

[0069] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0070] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A geogrid for foundation pit support, characterized in that: include: A grille body (1) having a first surface and a second surface opposite to each other; A geomembrane (2) is arranged on the first surface of the grid body; A plurality of reinforcing parts (3) are arranged on the second surface of the grille body (1); the end surface of the reinforcing part (3) away from the grille body (1) is formed with continuous wave crests and wave troughs.

2. A geogrid for foundation pit support according to claim 1, characterized in that: The reinforcing part (3) comprises a plurality of corrugated blocks arranged in parallel, and the wave crests and wave troughs are formed between two adjacent corrugated blocks.

3. A geogrid for foundation pit support according to claim 2, characterized in that: The corrugated block is one of a V-shape, a U-shape and a UV-shape.

4. The geogrid for foundation pit support according to claim 1, characterized in that: The grille body (1) comprises a plurality of grille bars alternately arranged horizontally and vertically, the grille bars having the first surface and the second surface, and the reinforcing portion (3) is arranged on the second surface of each grille bar.

5. The geogrid for foundation pit support according to claim 4, characterized in that: The first surface of the grid bar is provided with a rectangular bar (4).

6. The geogrid for foundation pit support according to claim 5, characterized in that: The rectangular strip (4) has a thickness of 1-2 mm and a width of 3-5 mm.

7. The geogrid for foundation pit support according to claim 1, characterized in that: The height difference between the wave crest and the wave trough is 3-5 mm.

8. The geogrid for foundation pit support according to claim 1, characterized in that: The geomembrane (2) is made of high-density polyethylene.

9. A construction method for foundation pit support, using a geogrid for foundation pit support according to any one of claims 1 to 8, characterized in that: include: Carry out several anchor bolt construction in the foundation pit; A plurality of the geogrids are hung on a plurality of the anchor rods.

10. A construction method for foundation pit support according to claim 9, characterized in that: The method of hanging the plurality of geogrids on the plurality of anchor rods comprises: A plurality of the geogrids are overlapped in sequence through the wave crests and wave troughs.

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