The slope protection technology of ecological bag retaining wall is to fill the ecological bags with foreign soil, and then connect the ecological bags with each other through connecting buckles, steel grids and other components to form a mechanically stable soft slope, which can not only prevent the soil from sliding, but also allow plants to survive and grow. The thickness of rooted soil is above 0.3m m.

(1) ecological bag

The ecological bag is made of geosynthetics such as polypropylene fiber or polyester fiber, which has the characteristics of high strength, corrosion resistance, non-degradation, ultraviolet resistance and good stability. The service life is over 70 years, and the recovery rate is 100%. Ecological bag has the function of filtering water and soil, which can not only prevent the loss of filler (mixture of soil and nutrients), but also realize the normal exchange of water in soil (figure 10-7).

Figure 10-7 Drainage coupling buckle and ecological bag

(2) Drainage coupling buckle

The connecting buckle connects countless ecological filling bags together to form a stable triangular internal friction tight internal lock structure. Its inverted hook claws are closely connected with the ecological bag to the maximum extent, and always keep vertical and close to the bag body, which plays an important role in building a stable slope.

(3) Ligation band

The necking belt is a self-locking black belt, which has the characteristics of ultraviolet resistance and strong tensile strength, and plays an important role in ensuring the safety and stability of the project.

(4) steel grille

When the reinforced grid (geogrid) is used to construct a steep backfill slope, the drainage connecting buckle connects the reinforced grid with the anti-ultraviolet ecological bag, and at the same time, the exposed bag wall is layered upside down, which plays an important role in the firmness and stability of the project (Figure 10-8).

Figure 10-8 Reinforcing Grille

2. Vegetation principles and methods

Try to use local native plant species, choose one or more vegetation methods, and try to use native plants. Spray seeding is suitable for large-scale greening operation, with fast construction speed and relatively low cost, suitable for various slope ratios, but not suitable for water level change and rainstorm weather; Interpolation is suitable for trees, shrubs and flowers, which enriches the plant level and can also construct various patterns.

3. Problems needing attention in the construction of ecological bag retaining wall

1) For the secondary ecological bag retaining wall, it is important to control the filling degree of the filler in the bag and ensure that the compactness of the filler in the bag is greater than or equal to 80%.

2) When filling the soil, it should be placed at the sign of the ecological bag to ensure uniform loading and weight (50 ~ 50~55kg) to avoid large deformation of the bag, and the filled soil mixed with fertilizer in the bag should be filled at a fixed point; When laying the ecological bag, it is forbidden to have joints between the upper and lower layers, and each process of laying the geogrid and setting the filter layer must be connected in place.

3) Fill the bottom four-layer ecological bag in strict accordance with the design requirements and according to the ratio of medium coarse sand to soil of 8: 2; Before laying the geogrid, the backfill soil at the back shall be leveled and compacted, and the flatness error shall be less than or equal to 5 cm; When laying geogrids, it is necessary to carry out reverse packing, and the overlap between the upper and lower geogrids is greater than or equal to 150cm.

4) Control the bottom ecological bag to be placed neatly and compacted, install drainage coupling buttons at the inner edge of the ecological bag joint at 1/2 between the upper and lower superimposed layers according to the design requirements, and lay drainage coupling buttons in full rows when there is a geogrid layer, so that the ecological bags can be integrated into a whole and the anti-tilt ability of the ecological bag wall can be increased.

5) When installing the bag body, it should be equipped with special molding tools, such as flat wooden rammer, iron rammer or log rammer. Plastic tools must have a certain weight to ensure the plastic effect. At the same time, there should be a fixed shaper at each operation point to reshape the slope, top surface and connecting side surface, so that the slope is smooth and the top surface is flat (especially where the ecological bags overlap), and the side ecological bags are tightly meshed to ensure the laying quality and appearance shaping quality of the ecological bags.

6) When placing the drainage coupling buckle, the coupling buckle must be tamped with a small log to ensure that the spikes of the drainage coupling buckle are completely pressed into the lower ecological bag, and then the upper ecological bag is punched by hand to ensure that the spikes of the coupling buckle are completely pressed into the upper and lower ecological bags to ensure that the upper and lower ecological bags are closely connected.

7) During plastic surgery, the ecological bag must be tamped manually first, and then leveled and compacted with a wooden rammer or an iron rammer; When placing the ecological bag, it is necessary to control the slope surface to be smooth, the top surface to be flat, and the thickness of each layer to be uniform. It is forbidden to tilt before the slope surface.

8) When laying the geogrid, first install a layer of ecological bag on it, then spread the geogrid flat, and press the soil in the middle and the back for pre-tightening; When geogrids are laid, the smoothness and compactness of the fill behind the wall must meet the design requirements.

9) The laying of the filter layer must be timely and standardized, the width must reach 40cm, and the joint between the filter layer and backfill soil must also be compacted and compacted.

10) Set drainage pipes and drains according to the design requirements. When backfilling to the top, slope drainage shall be done according to the gradient of 1% to ensure that surface water and seepage can be discharged smoothly in time and the wall bag is stable.

1 1) According to the technical requirements of spray sowing, do a good job of spray sowing on the bag wall, and arrange special personnel to seriously do the key procedures of post-maintenance work such as replanting, watering, fertilization and pest control. To ensure that the overall green coverage rate reaches 90%.

12) Pay attention to the weather forecast. Before the rainstorm, do a good job of earthwork covering and compaction, the apron slope of the covering soil must be well done, and the inverted filter layer must be laid in place. At the same time, the drainage tank must be cleaned in time after the rain, so as to ensure that the foundation tank of the ecological bag is drained smoothly without water accumulation, and the lower layer must not be soaked in water, otherwise the stability of the whole bag body wall will be seriously affected.

13) Due to the flexible structure of the bag wall, settlement and displacement will inevitably occur during the construction and after completion, especially in the summer rainstorm season. If the filling degree and compaction degree of the filler in the bag are insufficient, it will cause great settlement and displacement. Therefore, it is necessary to observe the settlement and displacement of the bag wall during construction. On the one hand, we should strictly control the filling degree of the fill in the bag and the compactness of the backfill behind the wall. On the other hand, after the settlement of the ecological bag wall is stable, the ecological bag can be laid. At the same time, the top package can also be placed at an ultra-high level and reserved for settlement.

14) technical disclosure shall be made to the construction team members entering the site in time to ensure that the main types of work master the construction technical essentials.