Advantages of self drilling hollow anchor bolts used as soil nails
by Una S. Website Marketing SpecialistSoil 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 11th 2021 20:48. Viewed 296 times.