Geocell, also called cellular restriction system, is a geosynthetic material,
In 1975, in order to quickly build roads on soft soil so that heavy machinery can pass through, the US Army Corps of Engineers and plastics manufacturer Presto jointly developed a cellular restriction system, the geocell. It is made of HDPE sheet and various auxiliary materials through extrusion, punching and welding.
The geocell is mainly used for soil reinforcement, highway slope protection, river liner, retaining wall construction and so on.
The honeycomb cell has high heat aging resistance. After the thermal oxidation test, its tensile yield strength can be reduced by 30% under the condition of 70 ℃, so that its service life can reach more than 50 years. It is suitable for different filling materials. . The specific features are as follows:
(1) Good mechanical properties, high load-bearing capacity and good dynamic performance, strong erosion resistance, under the effect of high lateral restriction, can make the whole structure anti-slip and anti-deformation, thereby effectively improving Subgrade bearing capacity and the ability to disperse loads.
(2) Flexible structure, which can adapt to slight undulations of the terrain, can adapt to a certain uneven settlement, retain the natural shape of the terrain, has good structural safety and few engineering traces;
(3) Energy saving and environmental protection: local materials or low-cost materials can be used as cell fillers, and concrete is rarely used, which can greatly reduce material costs and possible transportation costs, thereby reducing costs;
(4) Ecological and beautiful: filled with suitable fillers, different plants can be planted, with beautiful appearance and good landscape;
(5) Less labor, no need for special mechanical equipment, simple and easy connection during construction, simple construction process, high engineering efficiency, and can be used repeatedly;
(6) Good durability: The material is lighter, has good wear resistance, stable chemical properties, good aging resistance, acid and alkali corrosion resistance, and can ensure its long-term durability.
(7) The height, length, and width of the honeycomb compartment can be adjusted according to the actual needs of the project.
1, working surface
The working surface should be kept as flat as possible, especially the slope surface. However, due to some reasons, when the working surface cannot be leveled, you should concentrate on avoiding cell cracking, otherwise the consequences will be disastrous.
The side slope of the pavement cell should be provided with a main drainage ditch and connected with the road side ditch so that the road surface water can be discharged in time.
The cell should be laid from top to bottom in the main force direction, so that the cell force direction is perpendicular to the roadbed, and must not be laid horizontally. Fully open the cell components, and nail a hook-shaped riveting pile on the top of each cell, then fix the pile and open the cell.
After the cell is opened and riveted, it is filled with soil and slapped firmly.
Geocells have been improved and developed since they entered the engineering field in China. From the original single polyethylene ultrasonic welding, they gradually developed into anchored geocells, plug-in geocells, micropile geocells, and welded geocells. Cells, nano honeycomb geocells, non-woven geocells, etc. The application field is getting larger and larger, and it is widely used in various projects such as roadbed, slope protection, river treatment, foundation reinforcement, etc.
From the conceptual point of view, the geocell is a three-dimensional mesh cell structure formed by reinforced HDPE sheet material through welding.
The geogrid is a two-dimensional grid or a three-dimensional grid with a certain height, which is made of high molecular polymers such as polypropylene and polyvinyl chloride through thermoplastic or molding.
Both are made of polymer composite materials and are widely used in a series of soft soil foundation reinforcement such as road construction, retaining walls and pavement crack resistance projects. Both have high strength, strong bearing capacity, small deformation, corrosion resistance, , The coefficient of friction is large, the life is long, the construction is convenient and fast, the cycle is short, and the cost is low.
1. From the perspective of mechanics, the geocell is three-dimensionally reinforced. The geogrid is flat reinforced.
2. In terms of shape and structure, the geocell is a three-dimensional mesh cell structure. The geogrid is a two-dimensional grid structure.
3. In terms of product characteristics and technical application comparison, lateral limitation and stiffness: geocell is better than geogrid; bearing capacity and dispersing load effect: geocell is better than geogrid; anti-skid and anti-deformation ability: geogrid Room is better than geogrid
4. In terms of economic costs, both are inexpensive and good-quality, and the price of geocell is slightly higher than that of geogrid.
1. It is flexible in expansion and contraction, and can be folded during transportation. It can be stretched into a net during construction, and filled with loose materials such as soil, gravel, concrete, etc., to form a structure with strong lateral restriction and large rigidity.
2. Light material, abrasion resistance, stable chemical performance, photooxidation resistance, acid and alkali resistance, suitable for different soils and deserts and other soil conditions.
3. High lateral restriction and anti-slip, anti-deformation, effectively enhance the bearing capacity of the roadbed and disperse the load.
4. Changing the geometric dimensions of geocell height, welding distance, etc. can meet different engineering needs.
5. Flexible expansion, small transportation volume; convenient connection and fast construction speed.
1. Stabilize the railway subgrade and lay it on the railway subgrade to increase the overall strength of the subgrade, prolong the service life of the subgrade, save daily maintenance costs, and significantly reduce the occurrence of train failures, and escort the trains during the railway construction. , Is widely used.
2. Stabilizing the highway subgrade can significantly reduce the stress split from the subgrade reflection to the pavement. The subgrade will not crack, and the pavement will not crack naturally, especially the northern urban roads with warm winters and cool summers and large temperature differences. As soon as winter comes, the asphalt pavement will be damaged. The cracking is serious, and it is very useful to use geocells to reinforce the roadbed.
3. The dikes and retaining walls that bear the load; the two slopes of the river course and the walls with large inclination angles are all specific projects using geocells, especially the river slopes that have been exposed to rain and snow for a long time in a humid environment. Climate, it is easy to collapse, and the honeycomb structure of the geocell can be used to fix the soil at the oblique point of view.
4. Shallow water channel management, the three-dimensional grid strengthens the power of the filling, prevents soil erosion and increases the load capacity, which can reduce the construction cost of the shallow channel and allow the design of the river crossing to meet the various conditions of traffic and soil quality.
5. Supporting pipelines and sewers can add overall pressure resistance
6. Mixed retaining wall with load-bearing gravity to prevent landslides;
7. Independent walls, wharves, breakwaters, etc., can quickly build independent walls or barrier walls, and can use permeable granular fill dikes or weirs. They are also widely used in wharves or flood dikes and other important coastal applications.
8. Management of deserts, beaches, river channels and riversides.
1. Working surface: The flatness of the slope is related to the result of grass planting protection in the geocell. When the slope is uneven, the laying of the geocell is prone to stress concentration, which will cause the cell's solder joints to crack and cause the cell to straddle and so on. Therefore, the slope must be leveled to the design requirements, and artificial slope repairs must be selected to remove pumice and dangerous rocks on the slope.
2. The main drainage ditch system should be set up on the side slope of the paving cell, and the interval between two adjacent ditches is 4m. The drainage ditch is connected with the road side ditch, so that the road area flows along the side ditch into the drainage channel and enters the road edge. In order to avoid water in the road surface and prevent the cell slope from being washed away.
3. Flatten the slope surface to remove some debris that is not conducive to the laying of the cell, so that the slope surface is flat and firm. You can also sprinkle a layer of high-quality soil first to facilitate the growth of plants.
4. The cell should be laid from top to bottom in the main force direction, so that the cell sheet weight is perpendicular to the roadbed. It must not be laid horizontally.
5. Open the geocell components, and nail a hook-shaped rivet pile at the top of each grid. The length of the rivet pile is required to be twice the height of the cell itself plus 30cm. Piles mainly play the role of opening the cell. The center and bottom of the bamboo and wood piles can also be used to stretch the cell. The top riveting pile mainly plays the role of hanging and riveting the cell. Better materials should be used. , Such as steel rods and so on.
6. After the cell is opened and riveted, fill the cell space from top to bottom with high-quality soil suitable for cultivating turf or grass seeds. The filling should be 1.2 times the height of the cell, and be beaten to be firm and planted in time. On vegetation.
7. When used for the lower slope of the highway, the drainage ditch should be connected with the shoulder retaining ditch to facilitate the drainage of the road area, and the slope protection should not be washed. Make the water-blocking ditch at the height of the upper slope flow into the drainage ditch to prevent the accumulated water from directly scouring the slope protection. The upper slope should try to use a geocell with a higher height.
8. After the construction is completed, re-inspection should be done. If the rivet piles are not fully tensioned and are not strong, they should be reworked in time until the turf or grass seeds are fully alive.
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