A self-anchored steel pipe support device and anchoring construction method thereof

Abstract

The present invention discloses a self-anchoring steel pipe support device and an anchoring construction method thereof, which belong to the technical field of foundation pit support. The self-anchoring steel pipe support device of the present invention comprises a steel pipe, a grouting pipe and an anchor bar, wherein the surface of the steel pipe is processed with a perforation for the slurry to pass through, and the anchor bar can be movably installed in the perforation, one end of which is located inside the steel pipe and the other end extends to the outside of the steel pipe. The grouting pipe is sleeved inside the steel pipe and can move freely along the length direction of the steel pipe. The surface of the grouting pipe is provided with serrations spaced apart along its length direction and matched with the anchor bar. The present invention can be widely used in deep foundation pit excavation support construction under geological conditions such as sandy soil layers and flowing soil layers, and plays a very important role in the stability of the foundation pit. Moreover, the entire device can be reused, energy-saving and environmentally friendly, and meets the needs of sustainable development.

Description

Technical Field

[0001] The present invention belongs to the technical field of foundation pit support, and more specifically, relates to a self-anchored steel pipe support device and an anchoring construction method thereof, which is suitable for deep foundation pit excavation and support construction in municipal and building construction. Background Art

[0002] During the construction of modern municipal and housing projects, on-site geological conditions sometimes differ significantly from those observed during initial surveys, hindering the implementation of design plans. Weak surrounding rock is a common rock mass encountered in municipal and housing projects. Because of its poor self-stabilization, it's crucial to control settlement and large deformation during construction to ensure safety.

[0003] Anchor support refers to a reinforcement method used in surface engineering projects such as slopes and deep rock foundation pits, as well as in underground chambers such as tunnels and stopes. Numerous engineering practices have demonstrated that driving anchor pipes into weak surrounding rock and grouting them effectively supports the weak surrounding rock, thereby controlling settlement and large deformation of the surrounding rock to ensure construction safety. Anchor rods not only provide effective support but also require less material, are low-cost, and facilitate mechanized operation. Furthermore, due to their simple construction process, rapid construction speed, and minimal headroom, they meet the requirements for rapid construction in weak surrounding rock projects. Therefore, the use of anchor pipes for supporting weak surrounding rock has become widely used.

[0004] For example, the Chinese patent application No. 2017200579916 discloses an anchor support structure with an anchor sleeve. The anchor support structure of the application includes an anchor rod with an anchor sleeve, and the anchor rod with the anchor sleeve includes an anchor sleeve and an anchor rod body; wherein the anchor rod body is a hollow tubular body, and a plurality of slurry holes are opened on the hollow tubular body, and the anchor sleeve is sleeved on the middle part of the anchor rod body; when in use, the anchor rod body is used to pass through the wall of the foundation pit and is tilted in the slope of the foundation pit, and cement slurry is poured into the anchor rod body, and part of the cement slurry is squeezed out from the slurry holes, so that the cement slurry fills the space between the drill hole and the rock mass, so that the anchor rod with the anchor sleeve is tightly engaged with the rock mass to form an anchor support structure.

[0005] However, in sandy soil and fluidized soil layers, the anchoring force of these traditional anchor rod support structures decreases significantly, resulting in relatively poor anchoring effectiveness. Furthermore, soil flow can lead to a loss of anchoring effectiveness. Furthermore, these traditional anchor rods provide a relatively small support area for foundation pit soil, resulting in relatively poor stability.

[0006] After searching, the Chinese patent application No. 2018107043326 discloses an M-level support anchor pipe, which includes: a steel pipe, M-level support wall groups are sequentially arranged on the steel pipe, at least two support walls in any level of support wall group are rotatably connected to the steel pipe, and M is an integer not less than 2. The wall opening rod is used to move within the steel pipe, pushing at least two support walls relative to the steel pipe from a retracted state embedded in the steel pipe to an expanded state outside the steel pipe; wherein, the N-level support wall group is in an expanded state, and N is a positive integer not greater than M. This application can improve the stability of the anchor pipe in the soft surrounding rock to a certain extent, but it cannot play a strong anchoring role in sandy soil layers or quicksand layers with epidemic properties.

[0007] In order to solve the above problems, the present invention proposes a self-anchored steel pipe, which can be widely used in the excavation and support construction of deep foundation pits in sandy soil layers and flowing soil layers. It plays a very important role in the stability of the foundation pit. The entire device is reusable, energy-saving and environmentally friendly, and meets the requirements of sustainable development. Summary of the Invention

[0008] 1. Problem to be solved

[0009] To address the relatively poor anchoring performance and support stability of existing anchor rod support structures, the present invention provides a self-anchoring steel pipe support device and its anchoring construction method. The self-anchoring steel pipe structure of the present invention effectively improves anchoring performance and provides better support stability for foundation pits, making it widely applicable in excavation and support construction of deep foundation pits in sandy and fluidized soil layers.

[0010] 2. Technical solution

[0011] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0012] The present invention provides a self-anchoring steel pipe support device, comprising a steel pipe, a grouting pipe and anchor bars, wherein the surface of the steel pipe is processed with through holes for slurry to pass through, and the anchor bars can be movably installed in the through holes, one end of which is located inside the steel pipe and the other end extends to the outside of the steel pipe. The grouting pipe is sleeved inside the steel pipe and can move freely along the length direction of the steel pipe. The surface of the grouting pipe is provided with serrations distributed at intervals along its length direction and matched with the anchor bars.

[0013] Furthermore, the anchor bar is composed of an anchoring section, a connecting section and a load-bearing section. In this type of structure, the load-bearing section pushes the anchor bar to move under the thrust of the serrations on the surface of the grouting pipe, thereby anchoring the anchor section to the soft surrounding rock.

[0014] Furthermore, it also includes a sleeve, which is sleeved on the outside of the grouting pipe and can move freely along the length direction of the flower steel pipe.

[0015] Furthermore, the surface of the grouting pipe is provided with a plurality of saw teeth evenly spaced along its circumference, and the spacing between adjacent saw teeth in the same saw tooth is 20-30 cm, and the saw tooth width is 20-30 cm.

[0016] Furthermore, the serrations are cast iron serrations with a width of 20 cm, and the surface of the grouting pipe is provided with three serrations that are evenly and symmetrically distributed.

[0017] Furthermore, the sleeve is a PVC tube with a thickness of 3-5 mm.

[0018] Furthermore, the flower steel pipe is a cylindrical hollow tube structure, and one end thereof is processed into a conical structure with a cone angle of 105°-120°.

[0019] Furthermore, a plugging cap is provided at the other end of the patterned steel pipe opposite to the conical structure. The plugging cap is made of rubber and has a thickness of 3-5 mm.

[0020] The anchoring construction method of the self-anchored steel pipe support device of the present invention comprises the following steps:

[0021] Step 1: Use the anchor bolter to drill holes in the sand layer according to the spacing and angles designed in the drawings, and then drive the self-anchored steel pipe support device into the holes;

[0022] Step 2: Push the grouting pipe. The action between the serrations on the surface of the grouting pipe and the anchor bar bearing section pushes the anchor bar to slide outward along the perforations on the surface of the flower steel pipe, so that the anchor bar anchoring section is anchored into the soil.

[0023] Step 3: When the anchoring section of the anchor bar is anchored in the soil layer and the grouting pipe is basically free of stress, a sleeve is placed on the outside of the grouting pipe to completely separate the anchor bar from the grouting pipe.

[0024] Step 4: Grout the entire device through the central hole of the grouting pipe. After the grouting is completed, install the plug cap and perform pressure compaction after installation;

[0025] Step 5. Finally, pull out the grouting pipe for reuse in the next anchoring construction.

[0026] Furthermore, during grouting, the principle of small pressure first and then pressurization is followed. The small pressure value is 0.01-0.02MPa, and the pressure value after pressurization is 0.04-0.06Mpa. After the installation is completed, constant pressure is used to supplement the pressure, and the pressure is kept controlled at 0.04-0.06MPa for 20-30s.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention provides a self-anchoring steel pipe support device, comprising a steel pipe, a grouting pipe and anchor bars. The serrations on the surface of the grouting pipe push the anchor bars into the soil along the perforations on the surface of the steel pipe, so that the anchor bars are in contact with the soil over the maximum area to increase friction resistance. The slurry is then diffused through the perforations on the steel pipe. After the slurry solidifies, the steel pipe, the anchor bars and the surrounding soil layer form a whole, thereby increasing the integrity and achieving the effect of enhancing anchoring. Compared with the existing steel pipe support device, the structural stability of the support device is effectively improved.

[0030] (2) The self-anchored steel pipe support device of the present invention optimizes the structure and distribution of the anchor bars, thereby further improving the stability of the anchoring of the support device to the surrounding soil. Furthermore, the support device of the present invention can be driven directly into the soil without the need for drilling with external drilling equipment, thereby greatly reducing the construction period and improving construction efficiency.

[0031] (3) The present invention provides a self-anchored steel pipe support device, wherein the grouting pipe has multiple uses. On the one hand, it serves as a force-bearing device to push the anchor bars so that the anchor bars are embedded in the soil layer to the maximum extent, thereby enhancing the anchoring effect and the structural stability of the overall support. On the other hand, as a grouting pipe for the steel pipe, the entire device can be directly grouted and reinforced through the central hole of the grouting pipe. At the same time, after the slurry solidifies, the grouting pipe can be directly pulled out and installed in the next steel pipe for reuse, thereby helping to reduce the cost of the project.

[0032] (4) The present invention provides a self-anchoring steel pipe support device, in which a sleeve is provided on the outside of the grouting pipe. The setting of the sleeve can support and fix the anchor bar, which is beneficial to ensure the structural stability of the support device and prevent the anchor bar from moving and shaking during the grouting process and the subsequent grouting pipe extraction process. On the other hand, it can also protect the grouting pipe and prevent the serrations on the grouting pipe and its surface from being affected by the slurry.

[0033] (5) The anchoring construction method of the self-anchored steel pipe support device of the present invention forms a whole by integrating the steel pipe, slurry, and anchor bars, and optimizes the structure of the steel pipe, thereby effectively improving the anchoring effect and the support stability of the entire support device. The steel pipe support device of the present invention is used for anchoring construction, and the specific anchoring construction process is optimized, especially the grouting process, so as to further ensure the support effect on the weak foundation and improve the stability and firmness of the support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic plan view of the structure of a self-anchored steel pipe support device according to the present invention;

[0035] Figure 2 It is a side view of the self-anchored steel pipe support device of the present invention;

[0036] Figure 3 for Figure 1 Cross-sectional view in the AA direction;

[0037] Figure 4 This is a state diagram (1) of the self-anchored steel pipe support device of the present invention;

[0038] Figure 5 This is a state diagram (2) of the self-anchored steel pipe support device of the present invention;

[0039] Figure 6 This is a schematic diagram of the final state of the self-anchored steel pipe support device of the present invention;

[0040] Figure 7 Schematic diagram of the anchor bar structure.

[0041] In the figure: 1, decorative steel pipe; 101, perforation; 2, grouting pipe; 201, serration; 3, anchor bar; 301, anchoring section; 302, connecting section; 303, load-bearing section; 4, casing; 5, plug cap. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to specific embodiments.

[0043] Example 1

[0044] Combine Figure 1-Figure 3 , a self-anchoring steel pipe support device of this embodiment includes a steel pipe 1, a grouting pipe 2 and an anchor bar 3, wherein the surface of the steel pipe 1 is processed with a through hole 101 for the slurry to pass through, and the anchor bar 3 can be movably installed in the through hole 101, one end of which is located inside the steel pipe 1, and the other end extends to the outside of the steel pipe 1. The grouting pipe 2 is installed inside the steel pipe 1 and can move freely along the length direction of the steel pipe 1. The surface of the grouting pipe 2 is provided with serrations 201 distributed at intervals along its length direction and matched with the anchor bar 3.

[0045] like Figure 7 As shown, the anchor bar 3 is composed of an anchoring section 301, a connecting section 302 and a load-bearing section 303. In this structural design, the load-bearing section 303, under the thrust of the serrations 201 on the surface of the grouting pipe 2, propels the anchor bar 3, thereby anchoring the anchor bar 3 to the weak surrounding rock. Specifically, the grouting pipe 2 is pushed, and the interaction between its surface serrations and the anchor bar load-bearing section 303 causes the anchor bar to move along the perforations on the corrugated steel pipe into the soil. The anchor bar 301 penetrates the soil, maximizing the contact area between the anchor bar 3 and the soil, thereby increasing frictional resistance and improving the anchoring effect and structural stability of the support device. Optimizing the structure of the anchor bar 3 further ensures the stability and firmness of the support device and the surrounding weak foundation support. In this embodiment, the grouting pipe 2 is set up to serve as a force-bearing device on the one hand, to push the anchor bars so that the anchor bars are embedded in the soil layer to the maximum extent; on the other hand, as a grouting pipe for the flower steel pipe 1, the entire device can be directly grouted and reinforced through the central hole of the grouting pipe 2; at the same time, after the slurry solidifies, the grouting pipe 2 can be directly pulled out and installed in the next flower steel pipe 1 for reuse, which is beneficial to reducing the project cost.

[0046] In addition, this embodiment also includes a sleeve 4, which is sleeved on the outside of the grouting pipe 2 and can move freely along the length of the steel pipe 1. The sleeve 4 can support and fix the anchor bar 2, which is conducive to ensuring the structural stability of the support device and facilitating the extraction of the grouting pipe 2, preventing the anchor bar 3 from moving and shaking during the grouting process and the subsequent extraction of the grouting pipe 2. On the other hand, it can also protect the grouting pipe 2 and prevent the grouting pipe 2 and the serrations on its surface from being affected by the slurry.

[0047] Example 2

[0048] This embodiment of a self-anchoring steel pipe support device has a structure similar to that of Example 1, differing primarily in that: In this embodiment, the surface of the grouting pipe 2 is provided with multiple, evenly spaced serrations 201 along its circumference. Multiple anchor bars 3 are provided on the surface of the steel pipe, corresponding to each serration 201. The spacing between adjacent serrations within a single serration 201 is 20-30 cm, and the serration width is 20-30 cm, thereby further ensuring effective support for the surrounding foundation. Specifically, the serrations 201 in this embodiment are cast iron serrations with a width of 20 cm. Three serrations 201 are evenly and symmetrically distributed on the surface of the grouting pipe 2. Once the anchor bars are anchored, the three anchor bars 3 are evenly arranged around a circle, with a central angle of 120° between them. This further enhances the steel pipe's reverse engagement and improves its tensile strength against the surrounding soil. In this embodiment, a plug cap 5 is provided at one end of the steel pipe 1. This plug cap 5 is made of rubber and has a thickness of 3-5 mm.

[0049] The anchoring construction method of the self-anchored steel pipe support device of this embodiment includes the following steps:

[0050] Step 1: Use the anchor machine to drill holes in the sand layer according to the spacing and angle designed in the drawing, and then drive the self-anchored steel pipe support device into the hole. The initial state of the self-anchored steel pipe support device when it is driven into the hole is as follows: Figure 4 shown.

[0051] Step 2: Push the grouting pipe 2, and push the anchor bar 3 to slide outward along the perforation 101 on the surface of the flower steel pipe 1 through the action between the serrations 201 on the surface of the grouting pipe 2 and the anchor bar bearing section 303, so that the anchor bar 3 anchoring section 301 is completely anchored into the soil. Figure 5 As shown;

[0052] Step 3: Figure 6 As shown, when the anchoring section 301 of the anchor bar 3 is anchored in the soil layer and the grouting pipe 2 is basically free of force (because the grouting pipe 2 will be subject to resistance from the sand in the process of pushing the anchor bar 3 upward into the sand layer, after one side of the anchor bar 3, i.e., the anchoring section 301, is parallel to the grouting pipe 2, the grouting pipe 2 will no longer be subject to resistance from the anchor bar 3 when pushing, and it is ensured that the anchor bar 3 has been successfully anchored in the soil layer), the sleeve 4 is sleeved on the outside of the grouting pipe 2, and the anchor bar 3 and the grouting pipe 2 are completely separated under the action of the sleeve 4;

[0053] Step 4: Grout the entire device through the central hole of the grouting pipe 2. After the grouting is completed, install the plug cap 5 and perform pressure compaction after the installation is completed;

[0054] Step 5: Finally, pull out the grouting pipe 2 for reuse in the next anchoring construction.

[0055] When grouting, follow the principle of small pressure first and then pressurization. The small pressure value is 0.01-0.02MPa, and the pressure value after pressurization is 0.04-0.06Mpa. After the installation is completed, constant pressure is used to supplement the pressure, and the pressure is kept at 0.04-0.06MPa for 20-30s.

[0056] Example 3

[0057] The self-anchoring steel pipe support device of this embodiment has a structure that is basically the same as that of embodiment 2, with the main difference being that the sleeve 4 of this embodiment adopts a PVC pipe with a thickness of 3-5mm, the steel pipe 1 is a cylindrical hollow pipe structure, and the other end thereof opposite to the plug cap is processed into a conical structure with a cone angle of 105°-120°. Therefore, the support device of this embodiment can also be directly driven into the soil layer without the need for the drilling construction of other external drilling equipment, which greatly reduces the construction period and improves the construction efficiency (the specific principle is: the soil layer in the forward direction is stirred by the cone angle, and then the anchor hole is expanded again by the anchor bar, so that the entire device can be easily driven into the soil layer). The inner diameter and thickness of the steel pipe 1 are determined according to the design requirements of the drawing. If there is no relevant design description in the drawing, the inner diameter is 3-5cm and the thickness is 5-8mm.

Claims

1. A self-anchored steel pipe support device, characterized by: The invention comprises a steel pipe (1), a grouting pipe (2) and an anchor bar (3), wherein the steel pipe (1) is a cylindrical hollow pipe structure, one end of which is processed into a conical structure; a through hole (101) is processed on the surface of the steel pipe (1) for slurry to pass through; the anchor bar (3) can be movably installed in the through hole (101), one end of which is located inside the steel pipe (1) and the other end of which extends outside the steel pipe (1); the grouting pipe (2) is sleeved inside the steel pipe (1) and can move freely along the length direction of the steel pipe (1); the surface of the grouting pipe (2) is provided with saw teeth (201) distributed at intervals along the length direction thereof and matched with the anchor bar (3); The anchor bar (3) is composed of an anchoring section (301), a connecting section (302) and a load-bearing section (303). "-type structure, the load-bearing section (303) pushes the anchor bar (3) to move under the thrust of the serrations (201) on the surface of the grouting pipe (2), thereby anchoring the anchor section (301) to the weak surrounding rock; The support device further comprises a sleeve (4), which is sleeved on the outside of the grouting pipe (2) and can move freely along the length direction of the decorative steel pipe (1); the sleeve (4) is a PVC pipe.

2. A self-anchored steel pipe support device according to claim 1, characterized in that: The surface of the grouting pipe (2) is provided with a plurality of saw teeth (201) evenly spaced along its circumference, and the spacing between adjacent saw teeth in the same saw tooth (201) is 20-30 cm, and the saw tooth width is 20-30 cm.

3. A self-anchored steel pipe support device according to claim 2, characterized in that: The saw teeth (201) are cast iron saw teeth with a width of 20 cm, and the surface of the grouting pipe (2) is provided with three saw teeth (201) that are evenly and symmetrically distributed.

4. A self-anchored steel pipe support device according to any one of claims 1 to 3, characterized in that: The thickness of the sleeve (4) is 3-5 mm.

5. A self-anchored steel pipe support device according to any one of claims 1 to 3, characterized in that: The cone angle of the conical structure at one end of the flower steel pipe (1) is 105°-120°.

6. The self-anchored steel pipe support device according to claim 5, characterized in that: The other end of the decorative steel pipe (1) opposite to the conical structure is provided with a plug cap (5), and the plug cap (5) is made of rubber and has a thickness of 3-5 mm.

7. An anchoring construction method of a self-anchored steel pipe support device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Use the anchor bolter to drill holes in the sand layer according to the spacing and angles designed in the drawings, and then drive the self-anchored steel pipe support device into the holes; Step 2: Push the grouting pipe (2), and push the anchor bar (3) to slide outward along the perforation (101) on the surface of the flower steel pipe (1) through the action between the serrations (201) on the surface of the grouting pipe (2) and the anchor bar bearing section (303), so that the anchor bar (3) is anchored in the soil; Step 3: When the anchoring section (301) of the anchor bar (3) is anchored into the soil layer and the grouting pipe (2) is substantially free of stress, that is, when the anchoring section (301) is parallel to the grouting pipe (2), the sleeve (4) is sleeved onto the outside of the grouting pipe (2), and the anchor bar (3) and the grouting pipe (2) are completely separated under the action of the sleeve (4); Step 4: Grouting is performed through the central hole of the grouting pipe (2) into the entire device. After the grouting is completed, the plug cap (5) is installed, and after the installation is completed, pressure is added to compact the device. Step 5: Finally, the grouting pipe (2) is pulled out for reuse in the next anchoring construction.

8. The anchoring construction method of the self-anchored steel pipe support device according to claim 7 is characterized in that: When grouting, follow the principle of small pressure first and then pressurization. The small pressure value is 0.01-0.02MPa, and the pressure value after pressurization is 0.04-0.06Mpa. After the installation is completed, constant pressure is used to supplement the pressure, and the pressure is kept at 0.04-0.06MPa for 20-30s.

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