Application of 3D Geonet Mats for Grass Slope Protection in Municipal Roads
Abstract: Slope protection engineering is a key point of road engineering. The stability of road slope is related to the stability of the road structure. With the development of science and technology, more and more new technologies have emerged. This paper makes a brief introduction based on the three-dimensional China 2D geonet suppliers net grass planting slope protection technology in a municipal slope protection project in our province, which can provide reference and reference for the selection and construction process design of grass seeds in the future three-dimensional plastic geonet manufacturers net grass planting slope protection project.
Keywords: three-dimensional high quality 3D geonet mat; slope protection engineering; grass planting; greening; bamboo nail; sowing; conservation
Slope protection engineering is a link in modern transportation and water conservancy construction. If it is not handled well, it will cause erosion or damage of slope due to heavy rain, flood, and storm, which will affect the safety and service life of traffic engineering and hydraulic engineering. Therefore, the role of slope protection engineering in the entire road, railway, and river embankment projects can not be ignored.
In recent years, geosynthetics have been increasingly used in transportation construction and water conservancy projects. However, in terms of slope protection engineering, most of the current concrete blocks, masonry or dry stone masonry are still used. Restoring vegetation, destroying the natural landscape, is not conducive to environmental protection requirements, and the construction is complicated, the construction period is long and the cost is high, and the protective effect is not ideal. A three-dimensional China 2D geonet suppliers mat is a special geosynthetic material developed for these problems.
At present, the three-dimensional high quality 3D geonet mat has been widely used in the protection of highways and river embankments, but it is still less applied on urban roads, and the greening of slopes is a must for urban roads.
2. 3D geonet mat
The three-dimensional plastic geonet manufacturers mat is a stable three-dimensional net structure formed by single or multi-layer plastic bumps and high-strength flat nets. The outer layer of the surface layer is uneven and the material is loose and flexible, leaving 90%. The above space can be filled with soil and sand. The underlying planar network has the characteristics of low elongation and high strength and plays a role in preventing the slope from sliding down.
The roots of the plants can pass through the entire geotextile mat in a comfortable and balanced manner, reaching depths of 0.5 to 2 meters deep, so that vegetation, mesh mats and soil form a strong composite mechanical interlocking system. The composite system has good flexibility, and can be settled when the slope is settled, which will not cause overhead, and is a permanent slope protection method.
The solid effect is very obvious. The test proves that when the turf is not formed when the slope angle is 45 degrees, the soil block rate of the three-dimensional China 2D geonet suppliers mat is as high as 97.5%, and when the slope is 60 degrees, the block rate is also high. 84%, the slope rate can still be as high as 60% when the slope angle is vertical. That is to say, on the vertical slope surface that should not or cannot retain the soil, due to the existence of the mesh mat, 60% of the soil can be retained, so the three-dimensional high quality 3D geonet mat has an excellent soil-fixing effect. Better than the flat screen, it is a new generation of the flat screen. Before the lawn grows, the mat can protect the slope from wind and rain. After the grass seeds are sprinkled, the mat can firmly protect the grass species from the wind and rain and distribute them evenly on the slope. After the turf grows, the net mat and the silt form a solid composite mechanical interlocking system, which can prevent heavy rain and gusty winds, and can withstand the impact of high water level and large flow, instead of concrete, masonry, etc. as permanent. Due to the rough surface of the mesh pad, the wind and water flow produces numerous small eddy currents on the surface of the mesh mat, which can play an energy-dissipating effect and promote the deposition of the carrier in the mesh mat. It is made of polymer material PE and anti-purple additive. It has reliable chemical stability and can last for several decades in the underground. Green vegetation can absorb motor vehicle exhaust, reduce noise, guide drivers’ vision, relieve drivers’ visual fatigue, and green roads, beautify the landscape, and protect the environment.
2.3 Effect comparison
Years of practice have proved that the traditional stone masonry method is not ideal, it is easy to lose, collapse or overhead, and the stone masonry method has higher requirements on the original slope surface, high labor intensity, slow construction, and destruction due to the inability to restore vegetation. Natural landscape. Simple grass planting or planting shrubs can not effectively protect the slope, and the three-dimensional plastic geonet manufacturers mat shows its strong vitality with its excellent comprehensive performance.
3. Construction method
3.1 flat slope
Eliminate debris such as weeds and gravel on the slope, and carefully level the slope surface;
3.2 Excavation trenches at the top of the slope and at the foot of the slope
3.3 Laying the net
According to the order from the top of the slope to the foot of the slope, the mat should be kept in the positive direction and close to the slope. It should not be suspended, skewed or wrinkled. The upper and lower grooves should have enough backpressure. The adjacent mesh mats should be overlapped, and the overlap width is greater than 5 cm. When the mesh mat needs to be connected up and down, the upper part of the slope should be pressed against the lower part of the slope by more than 10 cm.
3.4 Fixed mesh mat
The mesh mat is made of bamboo nails or U-shaped nails which are fixed in plum blossom shape. The left and right lap joints of the mesh mats and the bamboo joints at the upper and lower joints need to be encrypted. About 6 bamboo nails are used per square meter, and then the upper and lower grooves are backfilled and compacted.
3.5 sown grass
3.5.1 Artificial sowing
1 Evenly layer a fine layer of soil on the mat, the thickness is about half of the net height.
2 Evenly mix the grass seeds with fertilizer and fine soil at a ratio of 1:10, and evenly spread on the mesh mat. The upper part of the slope should increase the number of grass seeds.
3 After the spread is finished, wipe it with a broom to ensure that all the grass seeds fall into the mat. 4 Then evenly coat a layer of fine soil, the thickness of the soil should be slightly covered with a mesh mat, and it should be slightly photographed. 5 Covering straw, straw curtain or geotextile, etc., the covering layer should be uniform and not too thick, so as to cover the slope.
3.5.2 Mechanical spraying and planting grass
1 Cover the soil evenly on the mat to cover the mat slightly.
2 The grass seeds are uniformly stirred with auxiliary materials such as fertilizer, water-retaining agent, binder, fiber, etc., and sprayed by a special hydraulic spray machine.
3 Cover the geotextile or straw to moisturize.
After the construction is completed, watering, fertilization, etc. should be done.
3.6.1 When spraying water, it should be sprayed in a mist. The time is selected in the morning or evening. It is necessary to avoid strong sunlight.
3.6.2 Fertilizers should be scientifically selected based on the soil and the growth period of the grass.
3.6.3 Fertilization should be appropriate and timely.
4. Project examples
The highway and railway interchange and ancillary projects of a certain city in our province are located in the development zone. For the excavation of the road trough, the city railway and a highway are respectively passed, and the lowest point of the line is about 5.0 meters lower than the ground. The slope adopts 1:1 grading. The original design adopts hexagonal bricks to fully cover the slope. Since the surrounding environment of the ground is the development zone and many residential communities, in order to reduce the project cost and beautify the environment, the three-dimensional China 2D geonet suppliers mat is used for grass greening. Slope protection.
4.1 Choice of grass species
According to the construction time, the design of the Ketchie high-grass grass species imported from the United States has been carefully selected. The grass species has a dual role in the slope protection greening: First, it is forage-type tall fescue, with a very developed root system and root system. Up to 1 meter, part of the root system is distributed within 30cm of the soil, and the root system is developed. The soil is very strong. When the grass is flat, it can withstand heavy rain erosion and erosion, and the slope is protected from damage. Secondly, from the perspective of leaves and color, it has the characteristics of turf-type tall fescue. The leaves are bright and green, and the roots are very strong, covering very well, and it is a cold-season turf, green period. Very long, the effect of landscaping is also very obvious, and the grass has been promoted and applied for a long time in other projects in China.
4.2 Selection of seeding methods
According to the normal small slope and the flat sowing, the normal sowing plan can be used to establish a good seeding plan. However, because the slope of the project is very steep and the construction is difficult, if the normal spreading is used, the seed is difficult to exist on the slope and is affected by the effects of rainwater, wind and normal watering directly affect the quality of Caochengping. Therefore, according to the experience and scheme of the steep slope construction of expressway in our province, the stripping method is adopted. In order to ensure the quality of the project, the non-spinning is added after the whole sowing. The cloth is protected from water by the water, and after germination, the seeds are germinated evenly, the lawn is very good, and the effect is very obvious.
4.3 Construction Precautions
4.3.1 The position of the construction slope is in the wilderness, which makes it easy for weed seeds to spread through the wind and is easily eroded by weeds.
4.3.2 All the turf roots in the soil must be removed to ensure that there are no loose objects in the ping.
4.3.3 The combination of the planting soil and the original soil after the cover is required to be tight. Otherwise, the landslide phenomenon may occur when watering or raining, so that the slope of the entire surface layer is not stable after covering the soil.
4.3.4 During the construction process, in order to better protect the slope, the slope shall be laid with a three-dimensional high quality 3D geonet mat before the planting, and the slope may be protected from wind and rain before the lawn is grown.
Geotechnical net mat grass protection slope has been applied in many projects in China, and its effect is obvious. It not only reflects the role of slope protection itself but also has significant effects on greening and environmental protection. This kind of technology is not only applied on highways and local roads but also should be promoted and developed in urban road construction. According to the application effect in the highway and railway interchange and the auxiliary slope protection in a development zone of a certain city in our province, this kind of process is feasible, and the slope protection and greening effect are very good.