Spiral jujube-pit-shaped static pressure reaming anchor rod (cable) body construction equipment and method and anchor rod (cable) body

Abstract

The invention discloses a spiral date pit-shaped static pressure reaming anchor rod (cable) body construction device and method and an anchor rod (cable) body. The construction equipment comprises a tubular extruding and expanding main body and an internal extruding and expanding part, wherein an extruding and expanding hole with a helix angle of 15-35 degrees is formed in the side wall of the extruding and expanding main body; and the extruding and expanding piece forms a forming corner part which protrudes outwards under the pressure by hinging a movable plate mechanism. The construction method comprises the steps that after an anchor hole is drilled, equipment is lowered to the bottom of the hole; 8-35 MPa axial pressure is applied to enable the formed corner to extrude and expand the hole, static pressure compaction is conducted on the soil body to form a date pit-shaped expanded cavity, and the maximum diameter of the date pit-shaped expanded cavity is 1.8-2.5 times of the diameter of the anchor hole; the equipment is lifted up in a segmented mode according to the interval of 0.8-1.0 time of the diameter of the anchor hole, and continuously and spirally arranged expanded cavities are formed; and grouting and filling to form an integral anchoring body. According to the technology, traditional cutting is replaced by static compaction, and a reinforced compression zone is formed around a hole; the high-pressure grouting realizes the synergistic effect of the soil body, the slurry body and the anchor rod (cable), so that the anchoring performance of the soft stratum is obviously improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anchor rod (cable) body, and particularly relates to a "spiral date kernel-shaped" static pressure hole expansion anchor rod (cable) body construction equipment and a construction method. BACKGROUND

[0002] Anchor rod (cable) is the main engineering measure in rock and soil anchoring engineering. Research shows that in anchor rod (cable) engineering, the increase of the length of the anchoring section to a certain limit value has little effect on the improvement of anchoring force. Therefore, improving the anchoring force of anchor rod (cable) in soft strata such as loess, soil-like or soft rock has important practical significance for engineering safety, cost saving, energy saving and emission reduction, and environmental protection. The principle of the existing hole expansion anchor rod (cable) technology is to increase the hole diameter of the anchoring section by cutting off the soil or soft rock on the hole wall with a cutting blade, so as to improve the anchoring force. However, when the cutting blade cuts the soil or soft rock on the hole wall, the hole wall is not compacted, and the anchoring section hole wall is not compacted. The main reason for the increase of the anchoring force is the increase of the hole diameter, and the unit area side resistance between the grouting body and the hole wall does not increase. Therefore, the increase of the anchoring force by cutting the soil body has a limited range. SUMMARY

[0003] The present application aims to provide a "spiral date kernel-shaped" static pressure hole expansion anchor rod (cable) body construction equipment and a construction method to solve the problem of insufficient anchoring force of the existing anchor rod (cable) body.

[0004] I. Construction equipment A "spiral date kernel-shaped" static pressure hole expansion anchor rod (cable) body construction equipment, comprising: An extrusion and expansion main body, which is a tubular structure extending from bottom to top, has an upper pipe opening and a lower pipe opening, the lower pipe opening is provided with a sealing plate closing the lower pipe opening, and the side wall of the extrusion and expansion main body is provided with a plurality of extrusion and expansion holes opening from bottom to top, the extrusion and expansion holes are arranged in a spiral shape along the height direction of the extrusion and expansion main body, and the spiral angle of the extrusion and expansion holes is 15°-30°.

[0005] An extrusion and expansion piece, which is located in the extrusion and expansion main body, comprises an extrusion and expansion side plate fixed with the sealing plate, and the other end of the extrusion and expansion side plate is fixed with a load top plate, the extrusion and expansion side plate comprises a first fixed plate, a first movable plate, a second movable plate and a second fixed plate which are sequentially and hingedly connected from bottom to top, the first fixed plate is fixedly connected with the sealing plate, and the second fixed plate is fixedly connected with the load top plate; when the load top plate is pressed and moves downward, the first movable plate and the second movable plate are hingedly rotated to form an outwardly protruding shaped corner portion, and the shaped corner portion extends out of the corresponding extrusion and expansion hole.

[0006] The cross section of the extrusion and expansion main body is square or circular.

[0007] The bottom of the extrusion body is provided with a positioning tip.

[0008] II. Construction method A "spiral jujube core" static pressure hole expansion anchor body construction method, comprising the following steps: (a) drilling an anchor hole to the designed depth; (b) lowering the extrusion body to the bottom of the anchor hole, and the positioning tip abuts against the hole bottom; (c) applying a downward pressure of 8-35 MPa to the load top plate of the extrusion part, driving the first movable plate and the second movable plate to rotate to form a shaped corner part, which protrudes from the extrusion hole and extrudes the surrounding soil, and the pressure is maintained for 5-10 minutes to form a spiral distributed jujube core-shaped enlarged cavity; According to experience, the pressure maintaining time needs to be adjusted according to the plasticity of the soil, as shown in the following table 1: Table 1 Relationship between soil type and pressure maintaining time The diameter d of the jujube core-shaped enlarged cavity is 1.8-2.5 times the diameter D of the anchor hole; since the protruding height h (0.3D-0.5D) of the shaped corner part is the initial extrusion depth applied to the soil, and the soil undergoes plastic flow (shear dilatancy effect) after being extruded, resulting in actual radial displacement Δr>h, and finally forming a jujube core-shaped enlarged cavity with d=1.8D-2.5D and a long-short axis ratio of 1.2-1.5; Wherein, the diameter d of the jujube core-shaped enlarged cavity satisfies the following formula: d = D +2Δ r (1) In the formula, D : anchor hole diameter; Δ r : radial displacement of plastic deformation zone of soil; In the above formula (1), Δ r satisfies: Δr =k×h (2) In the formula, k is the shear dilatancy coefficient of the soil, which is calibrated by triaxial shear test and related to the soil type: k=1.8-2.0 for silty clay, k=2.0-2.3 for sand, and k=2.2-2.5 for soft rock; (d) releasing the pressure of the load top plate to make the shaped corner part retract into the inside of the extrusion body; (e) lifting the extrusion body to the next hole expansion depth, and repeating steps (c)-(d) to form a continuous spiral arrangement of jujube core-shaped enlarged cavities; the distance H between adjacent hole expansion depths is consistent with the spiral pitch of the extrusion hole; (f) lifting the extrusion body, lowering the anchor rod to the hole bottom, and fixing the anchor rod to the center of the anchor hole through the positioning support; (g) Inject cement slurry into the anchor hole through the grouting pipe, fill the anchor hole and all the date kernel-shaped expanded cavities at one time, and the grouting pressure is 0.8-2.0 MPa until the slurry returns from the hole.

[0009] III. Anchor rod (cable) body A spiral date kernel-shaped static pressure hole expansion anchor rod (cable) body comprises: An anchor rod body extending along the anchor hole axis; A plurality of date kernel-shaped expansion parts arranged in a spiral along the length direction of the anchor rod body, the diameter of the date kernel-shaped expansion part being 1.8-2.5 times the diameter of the anchor rod body; A cement slurry solidification body covering the anchor rod body and filling the cavities of all the date kernel-shaped expansion parts to form an integral anchoring body; The spiral angle of the date kernel-shaped expansion part is 15°-30°, and the center distance between adjacent expansion parts satisfies 0.8-1.0 times the diameter of the anchor hole.

[0010] Compared with the prior art, the core mechanism of the anchor rod (cable) body of the present application to significantly improve the anchoring force lies in: 1. Static pressure extrusion cavity forming The angle part is driven to extrude radially by the axial load, and the soil around the hole is plastically compacted by continuous extrusion instead of cutting, forming a reinforced compression zone on the hole wall and significantly enhancing the microscopic biting action of the slurry-soil interface; 2. Spiral date kernel arrangement structure The continuously spiral distributed date kernel-shaped cavities construct a spatially cooperative bearing arch network in the soil, so that the anchoring body resistance to uplift changes from discrete point distribution to continuous band distribution, greatly reducing the stress concentration risk of the anchor rod (cable) hole wall under the action of pulling load; 3. Micro-fissure permeation and cementation High-pressure grouting forces the cement slurry to penetrate along the micro-fissures of the extrusion cavity wall, forming a three-dimensional root system-like consolidation network, and realizing the macroscopic integration and cooperative deformation of the soil-slurry-anchor rod. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a cross-sectional view of the extrusion and expansion main body structure of the construction equipment of the "spiral date kernel-shaped" static pressure hole expansion anchor rod (cable) body of the present application.

[0012] Figure 2 It is a cross-sectional view of the extrusion and expansion part structure of the construction equipment of the "spiral date kernel-shaped" static pressure hole expansion anchor rod (cable) body of the present application.

[0013] Figure 3 It is a cross-sectional view of the extrusion and expansion part structure of the construction equipment of the "spiral date kernel-shaped" static pressure hole expansion anchor rod (cable) body of the present application. Figure 2 It is a structural pressure schematic diagram of the middle extrusion and expansion part.

[0014] Figure 4Schematic diagram of the arrangement of ordinary anchor rods, serial jujube-shaped extruded anchor rods and spiral jujube-shaped extruded anchor rods in Example 3 of the present invention.

[0015] Figure 5 Schematic diagram of the simulation calculation model of the helical rise angle of the anchor rod extrusion and expansion body in Example 3 of the present invention.

[0016] Figure 6 This is the Qs curve calculated by simulating the helical rise angle of the bolt extrusion body in Example 3 of the present invention.

[0017] Figure 7 3. The Ps curves of the pull-out test of the ordinary anchor rod, the serial jujube-shaped extruded anchor rod and the spiral jujube-shaped extruded anchor rod in Example 3 of the present invention.

[0018] Figure 8 This is a bar chart of the ultimate pull-out bearing capacity of the ordinary anchor rod, the serial jujube-shaped extruded anchor rod and the spiral jujube-shaped extruded anchor rod in the pull-out test in Example 3 of the present invention.

[0019] In the figure, 1-extruded main body, 11-upper pipe opening, 12-lower pipe opening, 13-sealing plate, 14-extruded hole, 2-extruded part, 21-extruded side plate, 22-load top plate, 211-first fixed plate, 212-first movable plate, 213-second movable plate, 214-second fixed plate, 23-molded corner, 3-positioning tip. DETAILED DESCRIPTION

[0020] The present invention will be further explained below with reference to specific embodiments.

[0021] Example 1 like Figures 1-2 As shown in the figure, the "spiral jujube-shaped" static pressure expansion anchor rod (cable) body construction equipment includes: 1. Assembly of the extrusion body 1 A Q345 seamless steel pipe (circular cross section, outer diameter Φ120mm) with a wall thickness of 12mm was selected, and 12 extruded holes 14 with a hole diameter of Φ40mm were milled from the bottom end upwards; The extruded and expanded holes 14 are arranged in a right-handed spiral line, with a helix angle α = 25° (error ± 1°), and the hole center spacing along the axial direction is 110 mm; A Φ120mm×10mm sealing plate 13 is welded to the bottom end of the steel pipe, and a conical positioning tip 3 (cone angle 60°, height 50mm) is welded at the center of the sealing plate.

[0022] 2. Mechanical strengthening design of extruded part 2 The extruded side plate 21 adopts a four-bar linkage: The first fixing plate 211 is welded and fixed to the sealing plate 13 (plate thickness 15 mm); The first movable plate 212 is hingedly connected to the first fixed plate 211 at one end and to the second movable plate 213 at the other end, and the second movable plate 213 is hingedly connected to the second fixed plate 214 at the other end, and a 10mm thick lug plate is welded at the hinge point; The second fixed plate 214 is welded to the load top plate 22 at the top; Key tolerance control: the outer convex height of the shaped corner 23 after the expansion of the movable plate is 52mm (aligned with the center of the expanded hole, deviation ≤0.5mm).

[0023] Example 2 Step 1: anchor hole forming A Φ130mm anchor hole is drilled at the pile site in the loess layer using a geological drilling machine, the hole depth is 15.0m (0.3m of drill cuttings is drilled beyond), the verticality deviation is ≤1%; After hole forming, high-pressure air is used to clean the hole (pressure 0.4MPa, duration 2min), and the thickness of the hole bottom sediment is ≤30mm.

[0024] Step 2: spiral extrusion cavity forming The extrusion main body 1 is lowered to the bottom of the hole, and the positioning tip 3 abuts against the hole bottom rock surface; The hydraulic station is connected to apply a downward pressure of 28MPa to the load top plate 22 (loading rate 0.5MPa / s), and the pressure is maintained for 300 seconds; Operation points: the pressure gauge pointer is stable in the 28±0.5MPa interval, indicating that the shaped corner 23 has completely extended out of the extruded hole 14; After pressure relief, the equipment is lifted by 110mm (precise control of the winch scale), and the extrusion is repeated; After 73 continuous operations from the bottom of the hole, an anchor segment with a total length of 8m is formed, which has a jujube core-shaped expanded cavity array with a spiral pitch of 110mm and a cavity diameter of Φ240mm.

[0025] Step 3: anchor rod installation and grouting The extrusion main body 1 is lifted, and a Φ32mm ribbed anchor rod is immediately lowered, and a positioning support (support outer diameter Φ100mm) is installed every 2m; Cement slurry with a water-cement ratio of 0.45 is injected through a Φ25mm grouting pipe: initial pressure 0.8MPa: slurry fills the jujube core-shaped cavity; final pressure 2.0MPa: continuous grouting until the slurry returns at the hole mouth, and the pipe is closed after 3min of pressure stabilization.

[0026] Example 3 1. Anchor rod (cable) body influencing factors The spiral angle α of the jujube core-shaped expanded part is an important factor that needs to be considered for the "spiral jujube core-shaped" static pressure expanding anchor rod (cable) body, therefore, numerical calculation models with different spiral angles α are established, and corresponding uplift bearing capacity comparative analysis is carried out.

[0027] The calculation model parameters are set as follows: the total length of the anchor is 16m, the free section is 8m, and the anchor section is 8m; the anchor hole diameter D = 130mm, the expansion body diameter d = 240mm, and the center distance between adjacent expansion bodies is 110mm. Among them, the top expansion body is located at a depth of 8m below the surface, and the expansion body spiral angle α is 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40° and 45° respectively. The calculation model formation parameter values ​​refer to the general weak formation parameters. The calculation model is as follows Figure 5 shown.

[0028] According to the simulation calculation results, the Qs curves under different spiral angles are drawn as follows Figure 6 As shown. Figure 6 It can be seen that the bearing capacity of the spiral extruded anchor is greater when the helix angle α is between 15° and 30°. The bearing capacity of the spiral extruded anchor is the highest and approaches a similar level when the helix angle α is between 15° and 25°. This indicates that when the helix angle α is between 15° and 25°, the synergistic effect between the extruded body and the surrounding rock and soil is optimal, resulting in the highest bearing capacity of the anchor. When the helix angle α is small (α = 5° and α = 10°), the load-bearing areas of the extruded body overlap, causing additional displacement in the soil between the plates and significant stress concentration, which prevents the full bearing effect of the interaction between the extruded body and the soil. As the helix angle increases (α = 15° to 30°), the mutual influence between the extruded bodies decreases, allowing each extruded body to interact with the surrounding rock and soil, fully realizing the synergistic effect between the two. However, a larger helix angle does not necessarily increase the pullout bearing capacity of the anchor. When the helix angle exceeds 30° (α = 35° and α = 40°), the bearing capacity of the anchor body actually decreases. In actual engineering, the helix angle of the spiral jujube-shaped extruded anchor can be controlled within α = 15° to 30° to fully utilize the synergistic performance of the extruded body and the surrounding rock and soil, thereby improving the bearing capacity of the anchor body.

[0029] , Anchor (cable) bearing capacity evaluation In-situ pullout tests were conducted on conventional anchors, tandem jujube-shaped extruded anchors (CN202410824137.2), and spiral jujube-shaped extruded anchors for the Guangdong Province Shanmei Expressway Reconstruction and Expansion Project. The test location was the roadside slope between LK0+154 and LK0+496. The topography and strata of the test site are as follows: (1) Topography This section of the slope is located in a low-mountain, hilly terrain (Zone I2). The terrain is steep and densely covered with vegetation, primarily planted eucalyptus trees. The natural slope gradient is 20-30°. The terrain is highly undulating, with ground elevations ranging from 236 to 265 meters, a relative height difference of approximately 29 meters.

[0030] (2) Stratigraphic lithology The slope stratum is mainly composed of Quaternary silty clay and tuff of Upper Jurassic Daoling Group (J3 a ). According to the revealed depth, from top to bottom, there are Quaternary residual slope (Q el+dl ) layer and tuff of Upper Jurassic Daoling Group (J3 d ), which shows obvious stratification structure and mechanical property difference.

[0031] The test arranges 6 holes of anchor rods in total, specifically 2 common anchor rods, 2 series jujube core extruded anchor rods and 2 spiral jujube core extruded anchor rods. The arrangement is shown in Figure 4 , and the included angle between all anchor rods and horizontal plane is 20°. Among them, 1-1 and 1-2 are common anchor rods, 1-3 and 1-4 are series jujube core extruded anchor rods, and 1-5 and 1-6 are spiral jujube core extruded anchor rods.

[0032] The test results are shown in Figures 7-8 , and it can be seen from Figure 7 that the ultimate bearing capacity of 1-1 common anchor rod is 454 kN, and the ultimate displacement is 41 mm; the ultimate bearing capacity of 1-2 common anchor rod is 414 kN, and the ultimate displacement is 38 mm; the ultimate bearing capacity of 1-3 series jujube core extruded anchor rod is 626 kN, and the ultimate displacement is 52 mm; the ultimate bearing capacity of 1-4 series jujube core extruded anchor rod is 750 kN, and the ultimate displacement is 28.8 mm; the ultimate bearing capacity of 1-5 spiral jujube core extruded anchor rod is 920 kN, and the ultimate displacement is 49.6 mm; the ultimate bearing capacity of 1-6 spiral jujube core extruded anchor rod is 910 kN, and the ultimate displacement is 34 mm.

[0033] It can be seen from Figure 8 that the average ultimate bearing capacity of common anchor rod is 434 kN; the average ultimate bearing capacity of series jujube core extruded anchor rod is 688 kN; and the average ultimate bearing capacity of spiral jujube core extruded anchor rod is 915 kN. The average ultimate bearing capacity of spiral jujube core extruded anchor rod is 2.11 times that of common anchor rod, and 1.33 times that of series jujube core extruded anchor rod; the average ultimate bearing capacity of series jujube core extruded anchor rod is 1.59 times that of common anchor rod. Spiral jujube core extruded anchor rod has greater bearing capacity, which greatly improves the anchoring performance of soft stratum.

Claims

1. A "spiral jujube-shaped" static pressure expansion anchor (cable) body construction equipment, characterized in that: include: An extrusion expansion body (1) is a tubular structure extending from bottom to top, the extrusion expansion body having an upper pipe opening (11) and a lower pipe opening (12), the lower pipe opening (12) being provided with a sealing plate (13) for closing the lower pipe opening (12), a plurality of extrusion expansion holes (14) being provided on the side wall of the extrusion expansion body from bottom to top, the extrusion expansion holes (14) being arranged in a spiral shape along the height direction of the extrusion expansion body, and the spiral rise angle of the extrusion expansion holes (14) being 15° to 30°; An extruded component (2) is located in an extruded main body (1), comprising an extruded side plate (21) fixed to a sealing plate (13), a load top plate (22) being fixed to the other end of the extruded side plate (21), the extruded side plate (21) comprising a first fixed plate (211), a first movable plate (212), a second movable plate (213) and a second fixed plate (214) hingedly connected to each other from bottom to top, the first fixed plate (211) being fixedly connected to the sealing plate (13), and the second fixed plate (214) being fixedly connected to the load top plate (22); when the load top plate (22) is pressed and moved downward, the first movable plate (212) and the second movable plate (213) are hingedly rotated to form a molded corner portion (23) that bulges outward, and extends an extruded hole (14) corresponding thereto.

2. The "spiral jujube-shaped" static pressure expansion anchor rod (cable) body construction equipment according to claim 1, characterized in that: The number of the extruded and expanded holes (14) is 8 to 12, and the center spacing of adjacent extruded and expanded holes along the axial direction is 0.8 to 1.0 times the designed anchor hole diameter.

3. The "spiral jujube-shaped" static pressure expansion anchor rod (cable) body construction equipment according to claim 1, characterized in that: The diameter of the extruded hole (14) is 0.3 to 0.4 times the diameter of the designed anchor hole; and the convex height of the formed corner portion (23) is 0.3 to 0.5 times the diameter of the designed anchor hole.

4. The "spiral jujube-shaped" static pressure hole expansion anchor rod (cable) body construction equipment according to claim 1, characterized in that: The cross section of the extruded body (1) is square or circular.

5. The "spiral jujube-shaped" static pressure hole expansion anchor rod (cable) body construction equipment as claimed in claim 1, characterized in that: A positioning tip (3) is provided at the bottom of the extrusion and expansion body (1).

6. A method for constructing an anchor rod (cable) body using the device according to any one of claims 1 to 5, characterized in that: The following steps are involved: (a) Drill anchor holes to the designed depth; (b) lowering the extrusion and expansion body (1) to the bottom of the anchor hole, with the positioning tip (3) abutting the bottom of the hole; (c) applying a downward pressure of 8 to 35 MPa to the load top plate (22) of the extrusion member (2), driving the first movable plate (212) and the second movable plate (213) to rotate to form a forming corner portion (23), so that the corner portion (23) extends from the extrusion hole (14) and squeezes the surrounding soil, maintaining the pressure for 5 to 10 minutes, and forming a spirally distributed jujube-shaped expansion cavity; (d) releasing the pressure of the load top plate (22) so that the formed corner portion (23) is retracted into the interior of the extruded body (1); (e) lifting the extrusion expansion body (1) to the next expansion depth, and repeating steps (c) to (d) to form a continuous spiral arrangement of jujube-shaped expansion cavities; (f) The extrusion and expansion body (1) is raised, and the anchor rod is lowered to the bottom of the hole, and the anchor rod is fixed to the center of the anchor hole by a positioning bracket; (g) Inject cement slurry into the anchor hole through the grouting pipe, filling the anchor hole and all the jujube-shaped expansion cavities at one time. The grouting pressure is 0.8~2.0MPa until grouting returns to the hole mouth.

7. The anchor (cable) body construction method according to claim 6, characterized in that: The diameter of the jujube-shaped enlarged cavity in step (c) is 1.8 to 2.5 times the diameter of the anchor hole.

8. The anchor rod (cable) construction method according to claim 6, characterized in that: The depth spacing H between adjacent expansion holes in step (e) is consistent with the helical pitch of the extrusion expansion hole (14).

9. A "spiral jujube-shaped" static pressure expansion anchor (cable) body, characterized in that: include: The anchor rod (cable) body extends along the axis of the anchor hole; Multiple jujube-shaped expansion parts are arranged in a spiral shape along the length of the anchor body. The diameter of the jujube-shaped expansion part is 1.8 to 2.5 times the designed anchor hole diameter. The cement slurry consolidation body covers the anchor body and fills all the cavities of the jujube-shaped enlarged parts to form an integral anchor body; The helix angle of the jujube-shaped enlarged portion is 15° to 30°, and the center distance between adjacent enlarged portions meets 0.8 to 1.0 times the designed anchor hole diameter.

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