It is a composite which is composed of reinforcing steel bars (namely soil nails or anchor rods) arranged in the slope and the surrounding soil, and it is a supporting structure similar to gravity retaining wall formed by the surface layer.
Construction requirements
1, drainage hole construction quality, filter layer structure, wall foundation pit excavation, wall concrete strength, bottom wall formwork, settlement joint (expansion joint) should be sealed in the first chapter.
2. The soil nailing wall shall be constructed according to the principle of "top-down, layered excavation, layered anchorage and layered blowout prevention", and the net shall be sprayed in time to ensure that the weathering instability of the slope is not exposed for a long time.
3. Before construction, grouting process test and soil nail pull-out test should be carried out according to the design requirements to verify the design parameters and determine the construction process parameters.
4, soil nailing drilling, it is forbidden to irrigation. Nail hole grouting method should be adopted at the bottom of the hole to ensure sufficient grouting, and the grouting pressure is 0.2MPa.
5, soil nailing wall construction should be carried out according to the design requirements.
6. When the suspension material is geosynthetics, appropriate sun protection measures should be taken to prevent the geosynthetics from aging. Before hanging the net, loose earth and stone on the slope should be removed.
7. The toe wall foundation pit construction should be completed as soon as possible, and measures should be taken to prevent the foundation pit from being soaked in water.
8. Before spraying concrete, field spraying test should be conducted to determine the construction process parameters.
9, spraying operation should be carried out from bottom to top. When the coating thickness is more than 7 cm, it should be sprayed in two layers. Effective measures should be taken during spraying to ensure that the drainage holes are not blocked.
10, sand, stone, cement, fly ash, mineral admixtures, additives and steel bars shall be used in accordance with Article10.14 of this standard.
1 1. The varieties, specifications and quality of geosynthetics for soil nailing walls should meet the design requirements. On-site acceptance should be carried out when entering the site, and its technical performance should be checked.
12, the arrangement of soil nailing holes and the length of soil nailing should meet the design requirements. During the drilling construction of soil nailing wall, irrigation is strictly prohibited.
13, the strength grade of soil nail hole anchoring mortar should meet the design requirements. Nail hole grouting method should be adopted at the bottom of the hole to ensure sufficient grouting. Grouting pressure should be 0.2MPa.
Extended data:
Soil nailing wall is not only suitable for temporary supporting structure, but also suitable for permanent structure. When applied to permanent structures, the thickness of sprayed concrete surface should be increased and its aesthetics should be properly considered. At present, the application fields of soil nailing wall mainly include:
(1) underpinning foundation;
(2) foundation pit enclosure or shaft;
(3) Slope retaining wall;
(4) Slope stability;
(5) Combined with anchor retaining wall for slope protection.
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