U.S. patent application number 17/622948 was filed with the patent office on 2022-07-21 for npr anchor rod.
The applicant listed for this patent is Manchao HE, Min XIA. Invention is credited to Hongyan GUO, Manchao HE, Hongchao LI, Min XIA.
Application Number | 20220228487 17/622948 |
Document ID | / |
Family ID | |
Filed Date | 2022-07-21 |
United States Patent
Application |
20220228487 |
Kind Code |
A1 |
HE; Manchao ; et
al. |
July 21, 2022 |
NPR ANCHOR ROD
Abstract
An NPR rock bolt according to the present disclosure comprises a
bolt body (1), a tray (2) and a lock (3). The bolt body (1) is an
NPR spiral steel bar, an outer surface of the NPR spiral steel bar
is provided with a number of convex spiral ribs, and the spiral
ribs have a spiral structure. The tray (2) and the lock (3) are
directly sleeved on a tail of the NPR spiral steel bar. The NPR
bolt according to the present disclosure can effectively solve the
problem in the prior art that conventional rock bolts have a low
elongation and cannot meet the requirement of large deformation of
the surrounding rock.
Inventors: |
HE; Manchao; (Beijing,
CN) ; XIA; Min; (Beijing, CN) ; GUO;
Hongyan; (Beijing, CN) ; LI; Hongchao;
(Cangzhou City, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HE; Manchao
XIA; Min |
Beijing
Beijing |
|
CN
CN |
|
|
Appl. No.: |
17/622948 |
Filed: |
September 27, 2020 |
PCT Filed: |
September 27, 2020 |
PCT NO: |
PCT/CN2020/117971 |
371 Date: |
December 27, 2021 |
International
Class: |
E21D 21/00 20060101
E21D021/00; E21D 21/02 20060101 E21D021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2019 |
CN |
201921859383.2 |
Claims
1. An NPR rock bolt, comprising a bolt body (1), a tray (2) and a
lock (3), wherein the bolt body (1) is an NPR spiral steel bar, an
outer surface of the NPR spiral steel bar is provided with a number
of convex spiral ribs, and the spiral ribs have a spiral structure;
and the tray (2) and the lock (3) are directly sleeved on a tail of
the NPR spiral steel bar.
2. The NPR bolt according to claim 1, wherein the tail of the NPR
spiral steel bar is untreated.
3. The NPR bolt according to claim 1, wherein the NPR spiral steel
bar has a yield strength of 800-950 MPa and a tensile strength of
900-1050 MPa, and a deformation displacement of the NPR spiral
steel bar is 200-350 mm/m.
4. The NPR bolt according to claim 1, wherein a nominal diameter of
the NPR bolt is 14-26 mm.
5. The NPR rock bolt according to claim 1, wherein the tray (2) is
a metal butterfly tray.
6. The NPR rock bolt according to claim 1, wherein the lock (3)
comprises a metal lock piece and a lock sleeve that cooperate with
each other.
7. The NPR rock bolt according to claim 1, wherein the spiral ribs
extend along an axial direction of the NPR spiral steel bar.
8. The NPR bolt according to claim 1, wherein the quantity of the
spiral ribs is 3-6.
9. The NPR rock bolt according to claim 1, wherein a number of the
spiral ribs are evenly disposed along a circumferential direction
of the NPR spiral steel bar.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the technical field of
concrete-related new materials, in particular to an NPR rock
bolt.
BACKGROUND
[0002] In the prior art, in the support of coal mine roadways and
tunnels, rock bolts are the most used support equipment in terms of
both scope and quantity. With the continuous increase of coal
mining depth, the roadway-surrounding rock often shows the
characteristics of large deformation, such as large deformation of
soft rock, large deformation of rock burst, large deformation of
impact, large deformation of gas outburst. In the current
supporting rock bolts, the bolt body has a low elongation and is
not suitable for the nonlinear large-scale deformation and failure
characteristics of surrounding rock in deep roadways. Under the
action of impact loads, the rock bolt may reach its yield strength
instantaneously, then fracture and failure occur, and its bearing
and protection capabilities are lost, which leads to destructive
situations such as repeated repairation of the roadway, distortion
of the steel frame, and cracking of the poured concrete.
SUMMARY
[0003] An embodiment of the present disclosure provides an NPR rock
bolt to solve the problem in the prior art that the conventional
rock bolts have a low elongation and cannot meet the requirement of
large deformation of the surrounding rock.
[0004] In order to achieve the above object, the present disclosure
provides an NPR rock bolt, comprising a bolt body, a tray and a
lock; the bolt body is an NPR spiral steel bar, an outer surface of
the NPR spiral steel bar is provided with a number of convex spiral
ribs, and the spiral ribs have a spiral structure; and the tray and
the lock are directly sleeved on a tail of the NPR spiral steel
bar.
[0005] Further, the tail of the NPR spiral steel bar is
untreated.
[0006] Further, the NPR spiral steel bar has a yield strength of
800-950 MPa and a tensile strength of 900-1050 MPa, and a
deformation displacement of the NPR spiral steel bar is 200-350
mm/m.
[0007] Further, a nominal diameter of the NPR bolt is 14-26 mm.
[0008] Further, the tray is a metal butterfly tray.
[0009] Further, the lock comprises a metal lock piece and a lock
sleeve that cooperate with each other.
[0010] Further, the spiral ribs extend along an axial direction of
the NPR spiral steel bar.
[0011] Further, the quantity of the spiral ribs is 3-6.
[0012] Further, a number of the spiral ribs are evenly disposed
along a circumferential direction of the NPR spiral steel bar.
[0013] The NPR rock bolt according to the present disclosure can
achieve uniform elongation (200-350 mm/m) when the
roadway-surrounding rock deforms greatly, and maintain a
substantially stable working resistance. Therefore, the NPR bolt
according to the present disclosure can absorb the energy of the
surrounding rock by means of transverse resistance and large
deformation, so as to still have a good supporting effect under the
condition of large deformation of the surrounding rock to ensure
the stability of the roadway.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a schematic diagram of the structure of an NPR
rock bolt according to an embodiment of the present disclosure;
and
[0015] FIG. 2 is a schematic diagram of a stress-strain curve of
the NPR rock bolt according to an embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0016] The present disclosure will be described in further detail
below with reference to the drawings and specific embodiments, but
they are not intended to limit the present disclosure.
[0017] Referring to FIG. 1 and FIG. 2, according to an embodiment
of the present disclosure, a NPR rock bolt with constant resistance
and large deformation is provided. The NPR rock bolt comprises a
bolt body 1, a tray 2 and a lock 3. The bolt body 1 is an NPR
spiral steel bar, an outer surface of the NPR spiral steel bar is
provided with a number of convex spiral ribs, and the spiral ribs
have a spiral structure. The tray 2 and the lock 3 are directly
sleeved on a tail of the NPR spiral steel bar.
[0018] The NPR rock bolt according to the present disclosure can
achieve uniform elongation (200-350 mm/m) when the
roadway-surrounding rock deforms greatly, and maintain a
substantially stable working resistance. Therefore, the NPR bolt
according to the present disclosure can absorb the energy of the
surrounding rock by means of transverse resistance and large
deformation, so as to still have a good supporting effect under the
condition of large deformation of the surrounding rock to ensure
the stability of the roadway.
[0019] Preferably, the tail of the NPR spiral steel bar is
untreated. For example, the tail of the NPR spiral steel bar is not
subject to any treatment such as thread rolling. Such structure has
the advantage of avoiding the stress concentration at the tail
thread, thereby avoiding the occurrence of tail thread cracking,
and effectively improving the elongation of the rock bolt.
[0020] Refer to the schematic diagram of stress-strain curve shown
in FIG. 2, in the present embodiment, the NPR spiral steel bar has
a yield strength of 800-950 MPa and a tensile strength of 900-1050
MPa, and the deformation displacement of the NPR spiral steel bar
is 200-350 mm/m. The maximum stress of bolt body is >210 KN, the
elongation is >20%, the anchoring force of bolt body is >200
KN, the anchoring length is >1 m, the bearing capacity of bolt
lock is >210 KN, and the bearing capacity of tray is >210
KN.
[0021] Preferably, the nominal diameter of the NPR bolt is 14-26
mm. As shown in FIG. 1, the tray 2 is a metal butterfly tray. The
lock 3 comprises a metal lock piece and a lock sleeve that
cooperate with each other. A hole is formed at the center part of
the tray 2 for the bolt body 1 to pass through. The metal lock
piece is sleeved on the tail of the bolt body and cooperates with
the lock sleeve to form a lock 3.
[0022] The structure of the bolt body 1 is as follows. The spiral
ribs extend along the axial direction of the NPR spiral steel bar.
The quantity of spiral ribs is 3-6. A number of spiral ribs are
evenly disposed along the circumferential direction of the NPR
spiral steel bar.
[0023] The NPR bolt according to the present disclosure can realize
constant resistance and large deformation, and in the roadway where
the NPR bolt according to the present disclosure is used as a
supporting equipment, when the roadway-surrounding rock is subject
to a certain deformation, the NPR bolt will be evenly stretched and
the deformation energy in the surrounding rock can be released, and
when there is large tensile deformation, the relatively stable
working resistance can be maintained, the stability of the roadway
can be realized, and the hidden safety hazards such as roof fall
and collapse can be eliminated.
[0024] It should be noted that the terminology used herein is only
for describing specific embodiments and is not intended to limit
the exemplary embodiments according to the present disclosure. As
used herein, the singular forms are intended to include the plural
forms as well, unless the context clearly indicates otherwise. It
should also be understood that when the terms "include" and/or
"comprise" are used in this specification, they indicate there are
features, steps, operations, devices, components, and/or
combinations thereof.
[0025] It should be noted that the terms "first" and "second" in
the specification, claims and drawings of the present disclosure
are used to distinguish similar objects, and are not necessarily
used to describe a specific order or sequence. It should be
understood that the terms used in this way are interchangeable
under appropriate circumstances so that the embodiments of the
present application described herein can be implemented in an order
other than those illustrated or described herein.
[0026] Of course, the above are only preferable embodiments of the
present disclosure. It should be noted that those skilled in the
art can make improvements and modifications without departing from
the basic principles of the present disclosure, and these
improvements and modifications shall also fall within the
protection scope of the present disclosure.
* * * * *