Advantages of self drilling hollow anchor bolts used as soil nails
by Anchor S. Web DesignerSoil nailing is currently an
important technology for reinforcing slopes such as mountains, dams, and building
foundations. However, the traditional technology is to drill holes first, and
then anchor bars are embedded in the holes and grouted and fixed. The
construction process not only faces problems of high construction difficulty,
low work efficiency, and high cost but also face the problem of poor
connection stability between soil nails and geological structures. In recent
years, self-drilling hollow anchor bolts have
been widely used in soil nail support due to their simple construction
technology and good anchoring effect. Today I will introduce the advantages of hollow soil nails.
What are self-drilling hollow anchor bolts?
Self-drilling hollow anchor bolts are composed of a hollow
anchor bar, nut, plate, coupler, centralizer, and drill bit. It can combine
drilling, grouting, and anchoring functions together. Without using casing pipe,
it can greatly improve the construction efficiency and shorten the construction
cost.
Construction
process
1. Preparation work. Check whether the functions of the drilling rig are normal, whether the drill bit and anchor rod are damaged, and
whether the rod body is unblocked, etc. After making sure that there is no
problem, screw the hollow anchor bar to the drill bit.
2. Drill and grout. Connect anchor rod and grouting pipe to
the drilling rig through a rotary grouting adapter, and simultaneously drilling
and grouting.
3. Coupler anchor rod. If a single anchor rod can’t reach
the designed drilling depth, a coupler can be used to meet the design
requirements.
4. Installation of the plate and nut. After grouting, install a plate and nut close to the construction surface to ensure the anchoring effect.
5. Field test. After the installation is completed, the
self-drilling anchor rod is tested for its pull-out force to check whether it
meets the design requirements.
Advantages
Traditional soil nail is installing solid steel bars into
pre-drilled holes and then grouted and anchored. Compared to traditional soil
nails, What are the advantages of self-drilling hollow soil nails?
1. In loose or easily collapsed geological conditions, no
casing is needed. Therefore, when installing soil nails, most of the drilling
rigs are small and can well cope with slopes and narrow spaces.
2. Simultaneous drilling and grouting process can increase
the grout body diameter and maximize the sheer force of the grout body/soil
interface.
3. Simultaneous drilling and grouting process is less vibrating,
which effectively reduces the interference to the surrounding soil.
4. The installation speed of hollow soil nails is twice
that of solid soil nails thanks to the construction technology.
5. Can replace the concrete retaining wall.
6. High-pressure grouting process can inject the cement grout
into the loose stratum, greatly increasing the grout diameter and its friction
force, and the anchoring quality is better than that of solid soil nails.
Through the introduction, we know that self-drilling hollow
anchor bolts used as soil nail is an efficient and economical ground support
method, which can control and improve the soil's natural stability.
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Created on Nov 9th 2021 20:26. Viewed 262 times.