5 Key Points When Supporting the Slopes of Deep Foundation with Self Drilling Anchor Boltsby Simone S. sinorockco
anchor bolts support construction does not require casing follow-up and is
economical and efficient. It is often used in foundation pit support, slope
protection, and tunnel advance support projects, and has a good support effect.
What are the precautions for self-drilling hollow anchors when supporting the
slopes of deep foundation pits in soft soil layers? Today, Sinorock will give
you an introduction.
What are self-drilling anchor bolts?
The Self-drilling anchor bolt is the core product of Sinorock,
which includes the R-thread system and T-thread system. Sinorock self-drilling
anchor bolt size range from R25 to R51, T30 to T200.
The Self-drilling anchor bolt system is composed of a hollow
anchor bar, coupler, nut, drill bit, plate, and centralizer. It can combine
drilling, grouting, and anchoring in one process. The self-drilling anchor bolt
system is safe, efficient, and convenient. It is suitable for broken rock,
loose soil, and geological conditions where is difficult to drill holes. It helps
to ensure the anchoring effect in complex ground conditions and achieve the
best construction result.
What should we pay more attention to?
Self-drilling hollow anchor rod construction is mainly composed
of three parts: drilling, drill pipe extension, and grouting. When drilling,
high-pressure air or water is usually used to clean the hole to prevent the
hole from being blocked. There are several points of attention during the
1. The earthwork shall be constructed according to the design in
vertical layers and horizontal jump sections. Before drilling the self-drilling
hollow anchor rod, the slope surface should be sprayed with concrete to reach
the corresponding design strength, and then the drilling support construction
should be carried out. The excavation and support construction of the next
layer is prohibited before the concrete strength and anchoring strength have
not reached the design requirements.
The excavation depth of each layer of soil varies with the
self-stability of the soil and the specific geological conditions. The
excavation height of each layer in sandy soil is 1.0～1.5m,
and it can be increased appropriately in cohesive soil.
2. After the earth excavation, the slope is repaired. According
to the design drawings, the horizontal and vertical distances of the anchor
rods are first determined to determine the hole positions, and then the support
construction is carried out.
3. Generally, DTH drills or anchor drills are used for drilling.
When drilling, the hollow rod body is connected to the drill bit, which is both
a drill rod and an anchor rod. If the length of a single anchor rod does not
meet the design requirements, the second, third, or more should be connected
with a connecting sleeve until the drill reaches the design depth.
4. During the drilling process of the self-drilling hollow
anchor rod, the method of grouting while drilling can be used. On the one hand,
the hole can be cleaned, and on the other hand, the slurry can penetrate the
soil around the hole wall during the drilling process. The fissure and the
anchor body form an anchor with a larger diameter. This kind of construction
method adopts secondary grouting. The water-cement ratio of the first grouting
should be 1:1, the pressure should not be less than 0.6MPa, the second grouting
pressure should not be less than 1.6 MPa, and the strength grade should not be
less than M20.
5. After the grouting is completed and the grout has solidified
to a certain strength, the waist beam can be installed on the exposed end of
the self-drilling hollow anchor rod, and then the backing plate and nuts are
installed to fix the anchor rod so that the anchor rod and the shotcrete panel
form a whole. Force.
The application of self-drilling hollow anchor rods in
foundation pit support can simplify the construction process, shorten the
construction period, and reduce the overall cost of the project. It has become
one of the very economical and efficient methods for foundation pit support.
Created on Jan 7th 2022 03:10. Viewed 198 times.