(2) Common types of traditional ecological slope protection and their advantages and disadvantages.

1. Planting grass for slope protection

Artificial grass planting for slope protection is a traditional plant protection measure, and grass seeds are simply planted on the slope by hand. It is widely used in soil cutting and embankment slope protection projects with low slope height and gentle slope, which are suitable for grass growth.

Advantages: simple construction and low cost.

Disadvantages: Due to uneven sowing of grass seeds, it is easy to be washed away by rain, and the survival rate of planting grass is low, which often fails to achieve satisfactory slope protection effect, resulting in gully erosion, topsoil loss and other slope diseases, leading to a large number of slope disease treatment and restoration projects, making this technology less applied in recent years.

2. Hydraulic spray seeding and grass planting for slope protection

Hydraulic spray sowing and planting grass for slope protection is a newly developed slope plant protection measure abroad in recent ten years. Grass seeds, fertilizers, adhesives, paper pulp, soil improvers and pigments are mixed with water in a mixing box according to a certain proportion, and then sprayed on the slope by mechanical pressure to complete the grass planting construction.

Advantages: ① simple construction and high speed; (2) The construction quality is high, and the grass seeds germinate quickly and evenly by spray sowing; ③ Good protection effect. Under normal circumstances, the coverage rate of plants on the slope can reach more than 70% after one month of spray sowing, and the protection and greening functions will be formed after two months; ④ Wide applicability. At present, hydraulic spray seeding and grass planting are widely used in slope protection and greening projects of highways, railways, urban construction and other departments in China.

Disadvantages: ① The ability of soil fixation and water conservation is low, which is easy to form runoff ditch and erosion; (2) Builders tend to cut corners, make fakes, and form superficial phenomena; ③ Due to improper variety selection and insufficient mixture, it is easy to cause soil erosion or gully erosion in the later stage.

3. Exotic plants for slope protection

The revetment of exotic soil vegetation is made of water-retaining agent, adhesive, anti-transpiration agent, granule, plant fiber, peat soil, humus soil, slow-release compound fertilizer and other materials, which are stirred by special machinery and blown to the slope to form exotic soil with a certain thickness. Then, the selected seeds, wood fiber, adhesive, water-retaining agent, compound fertilizer and slow-release nutrient solution are stirred by a spray seeder and sprayed into the soil layer on the slope.

Advantages: ① the matrix and seeds can be formulated according to geological and climatic conditions, with wide adaptability; ② The foreign soil is firmly combined with the slope; ③ The soil layer has good permeability and fertility; ④ Good drought resistance; ⑤ High degree of mechanization, high speed, simple construction and short construction period; ⑥ The vegetation protection effect is good, which can basically maintain the normal growth of plants without maintenance. This method is suitable for rock foundation, weathered rock and hard sand, road slope, mine, reservoir area and slope of wasteland with small slope.

Disadvantages: it is required that the slope is stable, the slope erosion is slight and the slope is large, which is not suitable for long-term submerged areas.

Step 4: Lay tiles.

Paving turf for slope protection is a traditional plant slope protection measure. Natural turf is laid on the slope manually.

Advantages: simple construction, low project cost, short time of turf formation, quick slope protection effect and less restriction by construction season.

It is suitable for slope protection engineering of soft rock with various soil properties, strongly weathered rock layers, poor diagenesis, easy source of turf nearby, high and low slopes and gentle slopes. Laying turf is one of the most widely used traditional slope plant protection measures.

Disadvantages: Due to the difficulty of early maintenance and management, the newly paved turf is easily affected by various natural disasters, which often fails to achieve satisfactory slope protection effect, resulting in slope disasters such as gully erosion, topsoil loss and landslide. As a result, a large number of slope disease treatment and restoration projects have been produced. In recent years, due to the shortage of turf sources, the role of laying turf for slope protection has been gradually limited.

(5) Grid ecological slope protection

Grid ecological slope protection is a grid composed of bricks, stones, concrete blocks, cast-in-place concrete and other materials. Plants are planted in the grid to form a comprehensive slope protection system of grids and plants, which can not only play the role of slope protection, but also restore ecology and protect the environment.

Grille ecological slope protection combines engineering slope protection structure with plant slope protection, and the slope protection effect is very good. Among them, cast-in-place grid ecological slope protection is a new patented slope protection technology, which has the advantages of strong slope protection ability, simple construction technology, reasonable technology, economy and practicality, and is a new generation of ecological slope protection technology with great practical value.