How Does a Self Drilling Soil Nails Stabilize Your Ground?

Soil nailing is a new soil retaining technology for soil excavation and slope stabilization. In foundation excavation, soil nailing has now become the support technology after piles, walls, braces and anchors.

What Is Soil Nailing?

Soil nails are slender rods placed in the in-situ soil at a relatively close interval, such as steel bars, steel pipes or self-drilling anchors, etc., and are usually wrapped with cement mortar or cement grout. The characteristic of the soil nail is that it contacts with the surrounding soil along the entire length, acts as a soil nail group, and forms a entirety body with the surrounding soil. When the soil deforms, through the bonding force or friction on the contact interface with the soil, The soil nails are passively tensioned, and the soil is restrained and reinforced or stabilized mainly through the tension force.

What Is Self Drilling Soil Nails?

Traditionally soil nails are mostly steel bars or steel pipes, etc. When encountering broken and difficult-to-hole geological conditions, casing drilling is usually used, which is low efficient and high cost. Self drilling soil nailing system is mainly composed of a hollow anchor bar, coupler, nut, bearing plate, drill bit and centralizer. Hollow anchor bar can be used as a drill pipe or a grouting pipe to realize simultaneously drilling and grouting. During construction, self drilling soil nails can work without casing, which can greatly improving construction efficiency and saving engineering costs.

self drilling anchor bolts

Self Drilling Soil Nails Application

Self drilling soil nails are used in

l  Embankment stabilization

l  Slope stabilization

l  Reinforcement of existing retaining walls

l  Excavation of retaining structures for high-rise buildings and underground facilities

l  Tunnel portal reinforcement for unstable and steep layered slopes

l  Temporary excavation support

l  Build or renovate abutments, etc.

l  Landslide treatment

l  Slope reinforcement of roads and embankments

self drilling rock bolts

Features and Advantages

l  Hollow core bar, no casing required, allowing simultaneous drilling and grouting

l  Especially suitable for fractured, difficult-to-porous formations such as clay, sand and gravel to uneven fills, boulders, gravel and weathered rock

l  A wide range of anchor rod diameters are available, from 25-51mm, including R and T thread

l  It can be connected and extended with a coupler, suitable for construction in limited spaces and that are difficult to access

l  Can bear tensile and shear stress

l  Can be drilled all directions, including upwards

l  Higher efficiency and stronger corrosion resistance than traditional drilling and grouting nails and driven nails

l  Suitable for temporary or permanent support, anti-corrosion soil nails are available

Self Drilling Soil Nailing Construction Process

1. Preparation:
Check whether the functions of the drilling rig are normal, whether the drill bits and anchor bars are damaged, and whether anchor bars unblocked, etc. After ensuring that there is no problem, connect hollow anchor bar with the drill bit;

2. Drilling and grouting: Connect hollow anchor bar and grouting pipe to the drilling rig through rotary grouting adapter, and perform grouting during the drilling process to achieve simultaneous drilling and grouting;

3. Coupling SDA Bolt: If the length of a single self-drilling anchor bolt does not reach the design drilling depth, couplers can be used to meet the design requirements;

4. Install the bearing plate and nut: After the grouting is completed, install the bearing plate and nuts in sequence on the exposed part of the self-drilling anchor  bolt outside the rock mass close to the construction surface to ensure the anchoring effect.


Self drilling soil nails have higher construction efficiency and stronger anti-corrosion performance than traditional driven soil nails and drilling-grouting soil nails. From a technical and economic point of view, it is especially suitable for formations ranging from clay, sand and gravel to uneven fill, boulders, crushed stone and weathered rock. As a professional anchoring product manufacturer in the industry, Sinorock focuses on the R&D and production of SDA anchor bolts and has rich practical experience. If you have any questions or are interested in self drilling soil nails, welcome to contact us.

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