CN101413244B - A Method of Strengthening Highway Subgrade Using Geogrid - Google Patents

Abstract

The invention relates to a geotechnical grid used for highway subgrade reinforcement and its application method. The grid net is made of high-strength and high-modulus polyvinyl chloride polymer vertically and horizontally to enhance the tensile strength of the ribs; the outer layer of the grid is covered with Modified rubber coating, the rubber is mixed with anti-aging agent, antioxidant and light shielding agent and other masterbatches; the surface layer of the grid longitudinal and transverse ribs has circular embossed threads, and the grid mesh is circular to reduce stress concentration , to enhance the extensibility of the ribs; there are double-sided "strengthening columns" at the joints of the grid ribs to prevent the sliding between the soil and the grid, enhance the shear performance of the subgrade, balance the settlement, and prevent the grid from being pulled out of the subgrade. The invention has the advantages of high strength of polymer material, external coating of modified rubber, small creep, high tensile strength and low tensile strain; the circular mesh, tendon thread and "reinforcing column" are fully occluded with the soil, A space composite strengthening structure is formed, which improves the overall shear strength of the subgrade and the performance of balanced settlement.

Description

A Method of Strengthening Highway Subgrade Using Geogrid

technical field

The invention relates to a geotechnical grid capable of increasing the strength of road subgrade and making the subgrade settle in a balanced manner and a using method thereof, belonging to the technical field of civil engineering.

Background technique

In the construction of highway subgrade, slope protection, and dam engineering, the method of adding geosynthetics to the soil is often used, such as geogrid. Through the embedded anchorage of the grid and the soil block and the friction between the grid and the soil, the strength of the soil can be enhanced and the purpose of balanced settlement can be achieved, especially widely used in road subgrades. High-strength polymer geogrids equipped with longitudinal and transverse ribs and hole structures are applied to civil engineering such as highway and railway subgrades, slope anti-seepage and landslides, and river embankment revetment, which increases the life of the project. At present, geogrids can be divided into plastic grids and fabric grids. The plastic geogrid has a relatively simple process and low cost, but it will show serious creep after long-term use, resulting in the degradation of structural stability. Fabric geogrid has good performance and strong creep resistance, but the process is cumbersome and expensive. At present, the main problem of geogrid used in road embankment is: the horizontally arranged grid is easy to move horizontally in the soil, and cannot effectively reinforce the soil. After the road has been in operation for a long time, it is not the grid that is broken. That is, the grille is pulled out of the subgrade, causing secondary damage to the slope protection.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the problems existing in the existing geogrid technology, and provide a high-strength geogrid net, which can prevent the grid from being broken and prevent the grid from being pulled out of the subgrade.

The technical solution of the present invention is characterized in that the grid mesh is made of high-strength and high-modulus polyvinyl chloride polymer vertically and horizontally to enhance the tensile strength of the ribs; the outer layer of the grid is covered with a modified rubber coating, and the rubber is mixed with There are masterbatches such as anti-aging agents, antioxidants and light shielding agents to enhance the creep resistance and corrosion resistance of the ribs; the surface of the vertical and horizontal ribs of the grid has ring-shaped embossed threads to increase the friction with the soil The mesh of the grid is circular to reduce stress concentration and enhance the extensibility of the ribs; there are double-sided "reinforcing columns" at the joints of the grid ribs, with a single side length of about 3 cm, forming a network composite structure with the soil, To prevent the sliding between the soil and the grid, enhance the shear performance of the subgrade, balance the settlement, and prevent the grid from being pulled out of the subgrade.

The method of use of the present invention: (1) Spread the loose soil onto the surface of the embankment, and control the compaction thickness at 30-50cm; (2) After compaction, spread the "reinforcing column" geogrid along the direction perpendicular to the driving direction To the surface of the embankment, a grid with a length of not less than 2m is left on the road shoulder for turning-up. When the grid is laid along the driving direction, the lap length should not be less than 20cm, and the "reinforcing column" is dislocated and lapped in the circular mesh of the grid. (3) Manually tighten the grid vertically and horizontally, and use a rubber hammer to knock the "reinforcing column" into the compacted soil, and then lay the second layer of soil and roll it. The soil is fully occluded; (4) Turn up the grid on both sides of the embankment to the road shoulder, overlap with the newly laid grid, and put the "reinforcement column" in the grid, and use a rubber hammer to knock the "reinforcement column" into the grid. Compact the soil and lay a third layer of soil.

Advantages of the present invention: (1) The high-strength and high-modulus polyvinyl chloride polymer material has high strength, the outer layer is coated with modified rubber, the creep is small, and it has the properties of high tensile strength and low tensile strain; (2) The circular mesh of the grid , reducing stress concentration, the grid ribs have ring-shaped embossed threads, which improve the friction with the soil, and the "reinforcing columns" at the nodes are embedded in the soil, preventing the sliding between the grid and the soil, round The mesh, rib thread and "reinforcing column" are fully engaged with the soil to form a space composite strengthening structure, which improves the overall shear strength of the subgrade and the performance of balanced settlement; (3) "reinforcing column" can be used at the grid overlap "Sleeve into the mesh of the grille, and no longer use iron wire to bind, thus avoiding the situation that the grille is easily bitten by the wire; (4) It has the low price of plastic grille and the high performance of fabric grille, and the construction is simple , strong operability.

The invention is suitable for geotechnical engineering fields such as road embankment, slope engineering, foundation engineering and the like.

Description of drawings

Figure 1 is a plan view of a geogrid used for roadbed reinforcement. In the picture: 1 grid circular mesh, 2 grid reinforcement columns, 3 ring-shaped embossed threads.

Fig. 2 is the A-A sectional view of the grid plan view of the invention. In the picture: 2 grid reinforcement columns.

Fig. 3 is a large sample diagram of 3 ring-shaped embossing threads in the grid plan view of the invention. In the picture: 2 grid reinforcement columns.

Fig. 4 is a schematic diagram of the grid of the invention being used to reinforce road subgrades. In the picture: 4 "reinforcing column" geogrids.

Detailed ways

Embodiment: (1) After laying 30cm thick compacted soil on the original ground, lay the geogrid of this invention on the embankment, and pave the road shoulder by 2-3m, and use it for backpacking; (2) Lay between the grids along the driving direction The connection length is 20-30cm, and the reinforcement column 2 is inserted into the grid mesh 1 to achieve the purpose of mutual embedding; (3) the grid is tightened vertically and horizontally, and the reinforcement column is first knocked into the compacted soil with a rubber hammer Then spread the loose soil on the grid. After rolling, wrap the overlaid part of the first layer of grid back to the shoulder position in reverse, and use a rubber hammer to knock the reinforcement column into the compacted soil to fix it; (4) Lay the second layer of grille on the compacted soil, overlay the road shoulder by 2-3m, and overlap with the shoulder wrapping grille, and then use a rubber hammer to knock the reinforcing column into the compacted soil to fix it; ( 5) Spread the loose soil on the grid, compact the soil according to steps (3) and (4), and lay the grid; (6) The roadbed after reinforcement is shown in Figure 3, and the slopes on both sides can be laid Planting soil, spraying grass seeds with hanging nets, greening slopes, and reinforcing columns on the slopes can play the role of fixing soil and hanging nets.

Claims (1)

1. one kind is adopted GSZ to carry out the method that highway subgrade strengthens; GSZ is worked out by the high-strength and high-modulus polyvinyl chloride polymer in length and breadth, and the GSZ skin is surrounded by the modified rubber coating, is mixed with age resister, antioxidant and photomask agent masterbatch in the rubber; Grid mesh (1) is circular; There is bilateral reinforcing prop (2) at grid muscle band node place, one-sided length 3cm, and there is round embossing screw thread (3) on the vertical horizontal bar band top layer of grid; GSZ is used for the enhancing of highway subgrade, it is characterized in that:

(1), after original ground is laid the thick compacted soil of 30～50cm, GSZ is laid on the embankment, the ultra shop of curb is not less than 2m, is used for back wrapping;

(2), follow that lap length is not less than 20cm between car direction GSZ, reinforcing prop (2) dislocation lap joint is inserted in the GSZ mesh (1), play the purpose of mutual build-in;

(3), the edge is in length and breadth to the tension grid; With rubber hammer reinforcing prop is knocked in the compacted soil earlier and fixed, will loosen the soil is laid on the grid again, after having rolled; The part of the ultra shop of first floor grid oppositely returned wrap the curb position, and knock in the compacted soil reinforcing prop fixing with rubber hammer;

(4), second layer grid is layered on the compacted soil, the ultra shop of curb is not less than 2m, and returns after the bag grid overlaps each other with curb, knocks in the compacted soil reinforcing prop fixing with rubber hammer;

(5), again will loosen the soil is laid on the grid, by the 3rd and the 4th one step process compacting soil body, lays grid;

(6), the roadbed after reinforcing, side slope is laid planting soil in both sides, hangs the net grass-seed of sowing grass seeds by duster, the greening side slope.

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