What Is Soil Nailing Wall Construction?

Soil nail wall construction is a technique used to bring soil stability in areas where landslides might be a problem. Soil nail can prevent landslides by inserting steel reinforcement bars into the soil and anchoring them to the soil strata. It is called Soil Nail because it’s like having a nail being hammered into the soil, where the nails, are the steel bars.

Depending on the complexity of the work, soil nailing can be ranging between $80 per square feet up to $200 per SF. Some contractors will use a software called Snail Plus to determine their design and complete preliminary assumptions on the soil nailing.

(This article comes from the balance editor released)

Screw Anchor and Soil Nailing in Georgia

Helical Anchors (also referred to as tiebacks) provide lateral stability to foundation walls and retaining walls with unbalanced earth pressures. Helical anchors can be installed with hand-held equipment, mini-excavators, skid steers, backhoes, trackhoes, or crane-supported rigs so the anchors can be installed in almost any application. This versatility, along with the ability to immediately load and test the anchors, make helicals a convenient and economical solution for a wide variety of projects.

ADVANTAGES

  • Predictable capacity
  • Helix blade configuration selected to achieve design embedment and capacity
  • All-weather installation
  • Can be installed in areas of limited or tight access
  • Installation does not generate spoils
  • Clean installation with no messy grout
  • Load tests can be performed immediately following installation
  • Available with optional hot-dip galvanizing for added corrosion protection

(This article comes from AquaGuard Foundation Solutions edit released)

What is the mechanism of soil nailing?

The shear strength of the soil is lower than the tensile strength of the soil is almost negligible, but the soil has a certain structural integrity. After the soil nails with certain length and density are placed in the soil, the soil nails work together with the soil to make up the deficiency of the soil’s own strength to form the composite soil. Soil nails in the role of composite soil are:

  1. Hoop beam skeleton effect. This is determined by the stiffness of the soil nail itself, its strength, and its spatial distribution in the soil. It has the effect of restraining the deformation of the soil, and make the composite soil to form a whole.
  2. Share the role. In the composite soil, the soil nail and the soil shared the external load and soil self-weight stress, soil nails play a role in sharing. The proportion of soil nails is determined by the relative stiffness ratio of soil nail to soil, the spatial position of soil nail and the stress level of composite soil.
  3. Stress transfer and diffusion. Under the same load, the strain level of the soil nail wall is lower than that of the soil slope, thus delaying the formation and development of the cracking field.

Soil Stabilization

Soil nailing is an economical technique for stabilizing slopes and for constructing retaining walls from the top down. This ground reinforcement process uses steel tendons which are drilled and grouted into the soil to create a composite mass similar to a gravity wall. A shotcrete facing is typically applied, though many architectural options such as precast panels or “green” vegetated cells are available for permanent wall facings.

Soil Nailing Advantages

  • Used to follow irregular curves.
  • Equipment is portable for tight spaces.
  • The technique is flexible, easily modified.
  • Creates less noise and traffic obstructions.
  • Less impact on nearby properties.
  • Requires minimum shoring space.

(This article comes from Rembco Geotechnical Contractors editor released)

What is Soil Nailing? Construction Guidelines and Tips

What Is Soil Nailing

Soil nailing is a technique used to bring soil stability in areas where landslides might be a problem. Soil nail can prevent landslides by inserting steel reinforcement bars into the soil and anchoring them to the soil strata. It is called Soil Nail, because it’s like having a nail being hammered into the soil, where the nails, are the steel bars.

Soil Nail Installation Process

Soil nail provides a resisting force against slope failures. Its construction process is faster than other similar methods. The construction procedure starts, drilling into the soil, where the nail, steel bar, is going to be placed. After the drilling has been completed, exact depth must be provided by the geotechnical engineer, the nail must be inserted into the drilled hole.

Then, it must be grouted into the soil to create a structure similar to a gravity wall. After placing the nail, a shot-Crete layer is usually placed as a facing material, to protect the exposed nail, and then other architectural options are placed over the shot-Crete, creating an aesthetic finish to the project.

Steel tendons typically used for drill-and-grout soil nails usually consist of 0.8 to 2.0 inch bars with a yield strength in the range of 60 to 72 Ksi. Drainage is a critical aspect of soil nail wall construction. Face drainage is virtually always used with permanent walls, and very commonly used with temporary walls.

Face drainage usually consists of synthetic drainage elements placed between the shot-Crete and the retained soil, and may be typically 8 to 12 inches wide synthetic strips or perforated pipes.

The grouted soil nail hole typically has a minimum diameter of 4 inches. Centralizers are placed around the soil nail to maintain an even thickness of grout around the bar. For permanent applications, nails may be epoxy-coated or provided with a protective sheath for corrosion protection.

Soil Nailing is not recommended to use on clayey soils, and or clean sands where the cohesion of the soil is minimum.

(This article comes from construction.about.com editor released)

Construction Procedure of a Soil Nail Wall

Soil nail walls consists of installing passive reinforcement (i.e., no post-tensioning) in existing ground by installing closely spaced steel bars or sections (i.e., nails) and placing a front face support. Soil nails are later grouted if they are installed in drilled holes. Ungrouted soil nails are also possible if nails (or steel sections) are driven into the ground.

Typical soil nail wall arrangement:

soil-nail-wall

Soil nail wall construction proceeds from the top to bottom, and head plates are installed on each nail.  Shotcrete or concrete is typically applied on the excavation face to provide continuity when a soil nail wall is constructed.  For a soil nail wall the general construction procedure involves:

a) Excavate for the first nail (soil must be sufficiently self standing)
b) Install the 1st nail.
c) Construct 1st phase shotcrete on soil face (optional if shotcrete is constructed) with wire mesh or other reinforcement if required.
d) Install soil nail head plate (with or without other attachments)
e) Construct 2nd phase shotcrete (depending on staging specifications).
f) Excavate to next soil nail level, and install next soil nail, shotcrete etc.
g) Repeat steps c) through f) until the final excavation level is reached.
h) Construct additional permanent facing if required.
* Drainage filters and drainage pipes are also commonly installed during construction.

soil-nailing-wall-details

Soil nailing is typically used to stabilize existing slopes or excavations where top-to-bottom construction is advantageous compared to other retaining wall systems. For certain conditions, soil nailing offers a viable alternative from the viewpoint of technical feasibility, construction costs, and construction duration when compared to ground anchor walls, which is another popular top-to bottom retaining system.

(This article comes from Deep Excavation editor released)

Soil Nailing and Its Action Mechanism

In recent years, the construction of the city with a large number of high-rise buildings, deep excavation technology is developing rapidly. Soil nailing is the recent development of a new type of retaining structure for the excavated soil and slope stability. It is composed of dense soil nailing group, reinforced in-situ soil and spraying concrete pavement waterproof and the necessary system. It can form a similar gravity retaining wall, in order to resist the pressures after the wall and other forces, so that the excavation slope stability. Because of its construction convenient, simple equipment, excavation and support operations can be carried out at the same time, short construction period, low cost, low pollution, stable and reliable and many other technical and economic advantages, soil nailing spread rapidly in the country, especially in areas of low groundwater levels.

Mechanism of soil nailing

Soil with low shear strength, tensile strength almost can be ignored, but the soil has a certain structural integrity. When excavation of foundation pit, soil in the critical height of slope is in an upright position, when more than the depth or overload on the ground and under the effect of other factors, the sudden overall damage will occur. Traditional retaining structure are based on passive restriction mechanism. Namely by its own strength and stiffness, bear the following lateral earth pressure, prevents damage to the overall stability of soil. Soil nailing is set in soil body with a certain length and density of soil nailing, work together with the soil and make up for a lack of tensile and shear strength of soil itself. Soil nailing and soil work together to form a composite soil that can greatly increase the strength and stiffness of the undisturbed soil. Experiment shows that the vertical carrying capacity of the soil nailing wall in the top about one times more than a plain wall. More importantly, soil nailing structure is recognized as a good ductile characteristics. Loaded during prime soil slope does not occur as sudden landslide, slope provides for the repair time, and reduce the loss caused by the slope of the slump.