Soil nailing: Difference between revisions

[[File:Soil Nailing Erwalls.pngjpg|thumb|Soil Nailing Technique]]

Four main points to be considered in determining if soil nailing would be an effective retention technique are as follows. First, the existing ground conditions should be examined. Next, the advantages and disadvantages for a soil nail wall should be assessed for the particular application being considered. Then, other systems should be considered for the particular application. Finally, cost of the soil nail wall should be considered.<ref name="FHWA-2003"/>{{rp|13–14}} Soil nail walls can be used for a variety of soil types and conditions. The most favorable conditions for soil nailing are as follows:. The soil should be able to stand unsupported one to two meters high for a minimum of two days when cut vertical or nearly vertical. Also all soil nails within a cross section should be located above the [[groundwater table]]. If the soil nails are not located above the groundwater table, the groundwater should not negatively affect the face of the excavation, the bond between the ground and the soil nail itself.<ref name="FHWA-2003"/>{{rp|14–15}} Based upon these favorable conditions for soil nailing stiff to hard fine-grained soils which include stiff to hard clays, clayey silts, silty clays, sandy clays, and sandy silts are preferred soils. Sand and gravels which are dense to very dense soils with some apparent cohesion also work well for soil nailing. Weathered rock is also acceptable as long as the rock is weathered evenly throughout (meaning no weakness planes). Finally, glacial soils work well for soil nailing.<ref name="FHWA-2003"/> A geotechnical exploration of the subsurface conditions at the site may be appropriate to determine soil strength data, groundwater levels, and soil/bedrock stratifications. Soil/bedrock samples obtained during the exploration can be tested in an approved geotechnical laboratory to determine appropriate design parameters for design of the soil nailing. The exploration would also provide insight, where desired, into the possible causes of instability or failure.