CN114134913A

CN114134913A - Construction method of prestress recoverable anti-seismic anchor rod for slope support

Info

Publication number: CN114134913A
Application number: CN202111323731.6A
Authority: CN
Inventors: 高幸; 贾金青; 梅国雄; 包小华; 张丽华
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2021-11-10
Filing date: 2021-11-10
Publication date: 2022-03-04
Anticipated expiration: 2041-11-10
Also published as: CN114134913B

Abstract

The invention discloses a construction method of a prestress restorable anti-seismic anchor rod for slope support. The anchor head comprises a backing plate, an anti-seismic device, a prestress applying device and an anchor. The slope supporting method comprises the following six steps: 1, drilling a hole; 2, installing an anchor; 3 grouting and maintaining; 4, constructing a retaining wall; 5, mounting an anchor head; 6, tensioning and locking. The prestress recovery comprises the following steps: 1, unsealing; 2 applying a pre-stress. The invention effectively solves the problems that the anchor rod is easy to damage under the action of an earthquake, the stress of the anchor rod body is uneven, the prestress loss cannot be recovered and the like in the slope support. The construction method of the anti-seismic anchor rod for the slope support, which is provided by the invention, has the advantages of excellent anti-seismic performance, automatic rod body stress adjustment and lossless recovery of anchor rod prestress, and has wide application prospect and remarkable economic and social benefits.

Description

Construction method of prestress recoverable anti-seismic anchor rod for slope support

Technical Field

The invention belongs to the technical field of slope reinforcement, and relates to a construction method of a prestress recoverable earthquake-resistant anchor rod for slope support, in particular to a slope support method and a prestress recovery method.

Background

A composite supporting system consisting of anchor rods and side slope retaining wall structures (lattice beams, concrete surface layers and the like) is a common side slope reinforcing technology. The anchor rod can provide required anchoring force for a supporting system, can effectively improve the anti-sliding resistance of the side slope, increases the stability and safety factor of the side slope, and ensures the safety and stability of the side slope.

An earthquake is one of main causes of landslide, and a traditional anchor rod does not have any anti-seismic measures, so that a side slope supporting system is usually damaged and fails under the action of the earthquake, so that landslide is caused, and serious consequences are caused. The conventional anchor rod mainly has the following problems: 1. under the action of earthquake, the stress of the anchor rod is increased rapidly, the rod body of the anchor rod is pulled off, the anchor body is pulled out, or the anchor rod shakes along the slope surface to generate shearing damage; 2. the prestress tension of the anchor rod is improper, so that different rod bodies are stressed unevenly, the stress of a certain rod body is suddenly increased under the action of an earthquake, the rod body is broken or is debonded from the anchoring body, and the ultimate bearing capacity of the anchor rod is reduced; 3. influenced by anchor rod creep or earthquake action, anchor rod prestressing force can take place to lose and unable the recovery to reduce side slope stability factor of safety, increase landslide risk.

Disclosure of Invention

Aiming at the technical problems, the invention aims to provide a construction method of an anti-seismic anchor rod for slope support, which has excellent anti-seismic performance, can automatically adjust the rod body stress and can restore the anchor rod prestress in a nondestructive mode.

The technical scheme adopted by the invention is as follows:

a slope supporting method of a prestress recoverable earthquake-proof anchor rod for slope supporting comprises an anchoring section, a free section and an anchor head; the anchor head comprises a backing plate, an anti-seismic device positioned on the backing plate, a prestress applying device and an anchor; the anti-seismic device comprises a self-aligning roller bearing a, arc-shaped limb claws and a spherical base, wherein a plurality of arc-shaped limb claws are uniformly distributed on the outer edge of the self-aligning roller bearing a, the inner sides of the arc-shaped limb claws are fixedly connected with the self-aligning roller bearing a, the spherical base is composed of a plurality of arc-shaped steel plates, and the top of each arc-shaped steel plate is fixedly connected with the outer side of one arc-shaped limb claw; the prestress applying device comprises a self-aligning roller bearing b, a prestress applying bolt, a nut and a cross-shaped elliptical bearing ring, the prestress applying bolt is fixedly connected with the inner edge of the self-aligning roller bearing b, the nut is positioned at the top of the cross-shaped elliptical bearing ring and is fixedly connected with the cross-shaped elliptical bearing ring, and the bottom of the cross-shaped elliptical bearing ring is fixedly connected with the bottom of the spherical base; the anchor is an annular body, the inner edge of the annular body is fixedly connected with the outer edge of the self-aligning roller bearing b, and the outer edge of the annular body is fixedly connected with the inner edge of the self-aligning roller bearing a;

the side slope supporting method of the recoverable anti-seismic anchor rod comprises the following steps:

the method comprises the following steps: drilling a hole in the anchor rod;

step two: placing an anchor rod body;

step three: grouting and maintaining the anchor rod;

step four: constructing a side slope retaining wall structure;

step five: installing an anchor head;

step six: and (4) prestress tension locking.

The working principle of the anti-seismic device is that when an earthquake comes, the axial extrusion deformation of the anti-seismic device (arc limb claw and spherical base) is carried out along the axial direction of the anti-seismic anchor rod, the axial stress of the anchor rod is adjusted, and the stress surge is avoided; along the slope surface direction of the side slope, the damage of the shearing force to the anchor rod body is resisted through the swinging effect of the spherical base, and therefore the anti-seismic effect of the anchor rod is achieved.

The self-aligning roller bearing a and the self-aligning roller bearing b are high-strength center roller bearings capable of bearing axial loads.

The bottom of the spherical base of the anti-seismic device is tangent to the base plate.

A plurality of circular through holes are uniformly arranged in the circumferential direction of the anchorage device, and the number, diameter and distribution of the circular through holes are determined according to the number, diameter and distribution of the anchor rod bodies; the circular through hole is provided with an anchor rod body clamping piece which is matched with the circular through hole; and step six, synchronously tensioning and locking a plurality of rod bodies of the same anchor rod in a grading manner.

The anchor rod body is a prestressed twisted steel or a steel strand.

When a plurality of rod bodies of the same anchor rod are synchronously tensioned in a grading way and locked synchronously, the prestress of each rod body is the same, and the axes of the anti-seismic device, the prestress applying device and the anchorage device are positioned on the same straight line; when synchronous graded tensioning and synchronous locking are carried out, and small difference exists in prestress of each rod body, the number of the rod bodies of the same anchor rod is preferably 2 or not less than 3, so that the anchor rod can realize uniform stress of each rod body. For example, when the rods of the anchor rods are synchronously locked after synchronous graded tensioning, due to the influence of construction process or construction quality, the prestress loss of each rod body is slightly different, so that the stress of each anchor rod body is uneven, and the prestress recoverable earthquake-resistant anchor rods slightly turn over through the anchorage devices, so that the stress balance of each rod body is realized.

The bottoms of the plurality of arc-shaped steel plates are fixedly connected to form the bottom of the spherical base.

The cross elliptical pressure bearing ring is two concentric elliptical rings which are perpendicular to each other.

And fifthly, when the anchor head is installed, the prestress applying bolt in the prestress applying device is rotated to the bottom of the nut.

And the anchor head of the prestress restorable anti-seismic anchor rod further comprises a protective shell, and the protective shell is installed and sealed after prestress tensioning and locking in the sixth step. Meanwhile, mortar or resin can be used for sealing and protecting the anchor, but subsequent unsealing is not hindered.

The invention also provides a prestress recovery method of the prestress recoverable earthquake-resistant anchor rod, for example, the prestress recovery is carried out on the anchor rod after the earthquake disaster, and the method comprises the steps of unsealing the anchor head; a pre-stress is applied. The prestressing is accomplished by rotating the prestressing bolt upwardly. The working principle is that when the anchor rod has prestress loss, the prestress applying bolt is rotated to enable the prestress applying bolt to move upwards relative to the nut, the prestress applying device drives the anchor to move upwards, and therefore the effect of secondary tensioning of the anchor rod body is achieved. Because the prestress applying device is provided with the cross-shaped elliptical bearing ring which also has the performance of extrusion deformation, the secondary application of the prestress applying device on the anchor rod can not influence the anti-seismic effect of the anchor rod.

The prestress recovery method further comprises anchor sealing.

The invention has the beneficial effects that:

1, excellent earthquake resistance. The anti-seismic device of the anchor rod is a mechanical swing type anti-seismic device and has axial and tangential bidirectional anti-seismic effects. Under the action of an earthquake, the anchor rod vibrates along the axial direction, and the anti-seismic device avoids stress surge through extrusion deformation of the base, so that axial anti-seismic is realized. During earthquake, the anchor rod can violently shake along the slope direction, and the anti-seismic device releases tangential stress in a mechanical swinging mode, so that the anchor rod is prevented from being subjected to shear damage, and the purpose of protecting the anchor rod is achieved.

2, the stress of the rod bodies is automatically adjusted, and all the rod bodies are stressed in a balanced manner. The ground tackle in this patent is non-fixed ground tackle, and the adjustment of accessible ground tackle self balances each body of rod stress that receives, realizes that each body of rod atress is balanced. Therefore, the rod body with larger stress can be prevented from being pulled off or pulled out under the action of an earthquake, and other rod bodies of the same anchor rod are prevented from being pulled off or pulled out due to overlarge stress, so that the anchoring failure is caused.

3, the prestress of the anchor rod can be recovered without damage. The anchor rod is influenced by the construction process, the creep characteristic and the earthquake action, the prestress loss can occur, the anti-sliding resistance of the side slope is reduced, and the hidden danger of landslide exists. The anchor rod has the prestress nondestructive recovery performance, and prestress is applied to the anchor rod through the prestress applying bolt and the cross-shaped oval pressure-bearing ring. Meanwhile, the cross elliptical bearing ring has the axial anti-seismic characteristic of extrusion deformation and the tangential anti-seismic function of synchronous swinging along with the anti-seismic device.

Drawings

FIG. 1 is a schematic view of the slope support of the present invention;

FIG. 2 is a schematic view of a prestressed restorable anti-seismic anchor rod according to the present invention;

FIG. 3 is a schematic view of an anchor head according to the present invention;

FIG. 4 is a cross-sectional view of FIG. 3A-A;

FIG. 5 is a schematic view of the anti-seismic state of the anchor head in earthquake;

FIG. 6 is a schematic view of a post-earthquake disaster anchor head prestress recovery state;

FIG. 7 is a schematic view of the anchor head automatically adjusting the rod body stress;

FIG. 8 is a schematic view of a self-aligning roller bearing;

FIG. 9 is a cross-sectional view of FIG. 8B-B;

FIG. 10 is a schematic diagram showing a 90-degree turning state of the self-aligning roller bearing;

wherein, 1, an anchoring section; 2. a free section; 3. an anchor head; 4. a base plate; 5. an anti-seismic device; 51. a self-aligning roller bearing a; 52. an arc-shaped limb claw; 53. a spherical base; 531. arc-shaped steel plate strips; 6. a prestress applying device; 61. a self-aligning roller bearing b; 62. a prestress applying bolt; 63. a nut; 64. a cross-shaped elliptical bearing ring; 7. an anchorage device; 8. a protective shell; 9. a rod body; 10. side slope retaining wall structure.

Detailed Description

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "longitudinal," "transverse," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention.

Example 1

As shown in fig. 1 to 6 and 8 to 10, a construction method of a pre-stress restorable type anti-seismic anchor rod for slope support includes an anchoring section 1, a free section 2 and an anchor head 3. The anchor head 3 comprises a backing plate 4, an anti-seismic device 5 positioned on the backing plate 4, a prestress applying device 6, an anchor 7 and a protective shell 8.

The anti-seismic device 5 comprises a self-aligning roller bearing a51, arc-shaped limb claws 52 and a spherical base 53, wherein a plurality of arc-shaped limb claws 52 are uniformly distributed on the outer edge of the self-aligning roller bearing a51, the inner sides of the arc-shaped limb claws 52 are fixedly connected with the self-aligning roller bearing a51, the spherical base 53 is composed of a plurality of arc-shaped steel plates 531, and the top of each arc-shaped steel plate 531 is fixedly connected with the outer side of one arc-shaped limb claw 52. The self-aligning roller bearing a51 is a high-gravity center roller bearing capable of bearing an axial load. The bottom of the spherical base 53 of the anti-seismic device 5 is tangent to the base plate 4, and the bottoms of the plurality of arc-shaped steel plates 531 are fixedly connected to form the bottom of the spherical base 53. The working principle is that when an earthquake comes, the axial extrusion deformation of the anti-seismic device 5 (the arc limb claws 52 and the spherical base 53) is carried out along the axial direction of the anti-seismic anchor rod, the axial stress of the anchor rod is adjusted, and the stress surge is avoided; along the slope surface direction of the side slope, the damage of the shearing force to the anchor rod body 9 is resisted through the swinging effect of the spherical base 53, and therefore the anti-seismic effect of the anchor rod is achieved.

The prestress applying device 6 comprises a self-aligning roller bearing b61, a prestress applying bolt 62, a nut 63 and a cross-shaped oval pressure-bearing ring 64. The cross elliptical bearing rings 64 are two concentric elliptical rings perpendicular to each other. The prestress applying bolt 62 is fixedly connected with the inner edge of the self-aligning roller bearing b61, the nut 63 is positioned at the top of the cross-shaped elliptical bearing ring 64 and is fixedly connected with the cross-shaped elliptical bearing ring 64, and the bottom of the cross-shaped elliptical bearing ring 64 is fixedly connected with the bottom of the spherical base 53. The self-aligning roller bearing b61 is a high-strength self-aligning roller bearing capable of bearing axial load.

The anchor 7 is an annular body, a plurality of circular through holes are uniformly arranged in the annular direction of the anchor 7, and the number, the diameter and the distribution of the circular through holes are determined according to the number, the diameter and the distribution of the anchor rod bodies 9; the circular through hole is provided with an anchor rod body 9 clamping piece which is matched with the circular through hole for use. The round through holes are uniformly arranged, and the anchor 7 can keep a balanced state after the prestress of the anchor rod body 9 is uniformly applied.

The inner edge of the anchor 7 is fixedly connected with the outer edge of the self-aligning roller bearing b61, and the outer edge of the anchor 7 is fixedly connected with the inner edge of the self-aligning roller bearing a 51.

The anchor rod body 9 is a steel strand.

The side slope supporting method comprises the following steps:

the method comprises the following steps: drilling a hole in the anchor rod;

step two: placing an anchor rod body 9;

step three: grouting and maintaining the anchor rod;

step four: constructing a side slope retaining wall structure 10;

step five: installing an anchor head 3;

step six: pre-stress tension locking;

step seven: and (7) sealing the anchor.

In the fifth step, when the anchor head 3 is installed, the prestress applying bolt 62 in the prestress applying device 6 should be rotated to the bottom of the nut 63.

In the sixth step, a plurality of rod bodies 9 of the same anchor rod are synchronously tensioned in a grading way and locked, the prestress of each rod body 9 is the same, and the axes of the anti-seismic device 5, the prestress applying device 6 and the anchorage device 7 are positioned on the same straight line.

And in the seventh step, mounting a protective shell 8 after the prestress tensioning and locking and sealing the anchor head 3. Meanwhile, mortar or resin can be used for sealing and protecting the anchor, but secondary unsealing is not hindered.

After the earthquake, the prestress loss of the anchor rod is recovered by the following steps:

step eight: unsealing the anchor head 3;

step nine: applying a prestress;

step ten: and (5) secondary anchor sealing.

In the ninth step, the prestressing is performed by rotating the prestressing bolt 62 upward. The working principle is that when the anchor rod has prestress loss, the prestress applying bolt 62 is rotated to enable the prestress applying bolt 62 to move upwards relative to the nut 63, the prestress applying device 6 drives the anchor 7 to move upwards, and the effect of secondary tensioning of the anchor rod body 9 is achieved. Because the prestress applying device 6 is provided with the cross-shaped oval bearing ring 64, and the cross-shaped oval bearing ring 64 also has the extrusion deformation performance, the secondary application of the prestress applying device 6 on the anchor rod does not influence the anti-seismic effect of the anchor rod.

Example 2

The construction method of the prestress recoverable earthquake-resistant anchor rod is the same as that of the embodiment 1, further, the number of the rod bodies 9 is 3, but in the sixth step, when the anchor rod is synchronously tensioned and locked, due to the influence of the construction process or the construction quality, the prestress tension value of each rod body 9 or the prestress loss during locking is slightly different, so that the prestress applied to each rod body 9 is unbalanced, as shown in fig. 7, when the prestress applied to each rod body 9 is unbalanced, the anchor 7 is slightly turned, one end of the rod body 9 with larger prestress sinks, so that partial prestress is released, one end of the rod body 9 with smaller prestress is lifted, so that partial prestress is applied, and when the prestress applied to each rod body 9 is the same, the anchor 7 is not turned over, so that a new mechanical balance state is achieved. Because the inner edge of the anchor 7 is fixedly connected with the outer edge of the self-aligning roller bearing b61, and the outer edge of the anchor 7 is fixedly connected with the inner edge of the self-aligning roller bearing a51, when the anchor 7 is turned over, the anti-seismic device 5 and the prestress applying device 6 are not affected, the original position is still kept, and the original function is realized.

The construction method effectively solves the problems that the traditional anchor rod has no shock resistance, the anchor rod is easy to damage under the action of an earthquake, the stress of the anchor rod body is uneven, the prestress loss cannot be recovered and the like in the slope support, has excellent shock resistance, can automatically adjust the rod body stress, and can recover the prestress of the anchor rod without damage, and has wide application prospect and remarkable economic and social benefits.

Claims

1. A slope supporting method of a prestress restorable anti-seismic anchor rod for slope supporting is characterized in that: the restorable anti-seismic anchor rod comprises an anchoring section (1), a free section (2) and an anchor head (3); the anchor head (3) comprises a backing plate (4), a prestress applying device (6), an anchor (7) and an anti-seismic device (5) positioned on the backing plate (4); the anti-seismic device (5) comprises a self-aligning roller bearing a (51), arc-shaped limb claws (52) and a spherical base (53), wherein a plurality of arc-shaped limb claws (52) are uniformly fixed on the outer edge of the self-aligning roller bearing a (51), the spherical base (53) is composed of a plurality of arc-shaped steel plates (531), and the top of each arc-shaped steel plate (531) is fixedly connected with the outer side of one arc-shaped limb claw (52); the prestress applying device (6) comprises a self-aligning roller bearing b (61), a prestress applying bolt (62), a nut (63) and a cross-shaped oval pressure-bearing ring (64), the prestress applying bolt (62) is fixedly connected with the inner edge of the self-aligning roller bearing b (61), the nut (63) is positioned at the top of the cross-shaped oval pressure-bearing ring (64) and is fixedly connected with the cross-shaped oval pressure-bearing ring (64), and the bottom of the cross-shaped oval pressure-bearing ring (64) is fixedly connected with the bottom of the spherical base (53); the anchor (7) is an annular body, the inner edge of the annular body is fixedly connected with the outer edge of the self-aligning roller bearing b (61), and the outer edge of the annular body is fixedly connected with the inner edge of the self-aligning roller bearing a (51);

s1: drilling a hole in the anchor rod;

s2: placing an anchor rod body (9);

s3: grouting and maintaining the anchor rod;

s4: constructing a side slope retaining wall structure (10);

s5: installing an anchor head (3);

s6: and (4) prestress tension locking.

2. The method of slope supporting using a pre-stress restorable earthquake-proof anchor rod for slope supporting according to claim 1, wherein: the self-aligning roller bearing a (51) and the self-aligning roller bearing b (61) are high-strength self-aligning roller bearings capable of bearing axial loads.

3. The method of slope supporting using a pre-stress restorable earthquake-proof anchor rod for slope supporting according to claim 1, wherein: the bottom of the spherical base (53) is tangent to the backing plate (4).

4. A method of slope supporting using a pre-stressed recoverable earthquake-resistant anchor rod as claimed in claim 1 or claim 2, wherein: a plurality of circular through holes are uniformly arranged in the circumferential direction of the anchorage device (7), and the circular through holes are matched with anchor rod bodies (9) clamping pieces which are used in a matched mode; and S6, synchronously and hierarchically stretching and locking a plurality of rod bodies (9) of the same anchor rod.

5. The method of slope supporting using a pre-stress restorable earthquake-proof anchor rod for slope supporting according to claim 4, wherein: the number of the same anchor rod body (9) is 2 or not less than 3.

6. The method of slope supporting using a pre-stress restorable earthquake-proof anchor rod for slope supporting according to claim 1, wherein: s5, when the anchor head (3) is installed, the prestress applying bolt (62) of the prestress applying device (6) is rotated to the bottom of the nut (63).

7. The method of slope supporting using a pre-stress restorable earthquake-proof anchor rod for slope supporting according to claim 1, wherein: the anchor head (3) of the prestress restorable anti-seismic anchor rod further comprises a protective shell (8), and the protective shell (8) is installed after prestress tensioning and locking in S6 and is used for sealing the anchor head (3).

8. A method of restoring the prestress of a prestressed restorable earthquake-resistant bolt according to the method of claim 1, comprising the steps of:

s1: unsealing the anchor head (3);

s2: applying prestress: this is done by rotating the prestress applying bolt (62) upward.

9. The prestress recovery method of a prestress recoverable earthquake-resistant anchor rod according to claim 8, wherein: also comprises a sealing anchor.