A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation

Abstract

The present invention relates to the technical field of foundation pit enclosure, and discloses a method for pre-embedded embedding of a cylindrical anchor structure for reducing the amount of foundation pit excavation, comprising the following steps: S1: tying a steel cage; S2: installing an inclined support on the steel cage; S3: filling a filler inside the inclined support; S4: placing the steel cage into a pile hole, and pouring a concrete pile body, wherein the inclined support and the steel cage are integrally embedded in the pile body; S5: excavating a foundation pit, finding the pre-embedded inclined support, and removing debris from the inclined support, drilling an anchor hole, placing an anchor cable, and grouting the anchor hole; S6: after the anchor hole grouting body reaches a specified strength, installing the anchor in the inclined support, clamping the anchor cable, tensioning the anchor cable, and sealing the anchor. The technical solution of the present invention can reduce the amount of foundation pit excavation, reduce construction costs, and at the same time, shorten the construction period, and avoid the risk of high-altitude operations caused by fertilizer tank filling operations.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit enclosure, and in particular to a method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation. Background Art

[0002] Foundation pit support is a measure of support, reinforcement and protection for the side walls of the foundation pit and the surrounding environment to ensure the safety of underground structure construction and the surrounding environment of the foundation pit.

[0003] The existing foundation pit support structure is as follows Figure 1 As shown, the pile body 19 includes a pile body 19 and an anchor 15. A steel cage is provided inside the pile body 19. The steel cage serves as the skeleton of the pile body 19 and can improve the bearing capacity of the pile body 19. The pile body 19 is formed by pouring concrete around the steel cage. The anchor 15 is arranged outside the pile body 19. An inclined support 4 is provided between the pile body 19 and the anchor 15. The inclined support 4 is fixed to the left side wall of the pile body 19. A through hole 20 connected to the anchor hole 22 is provided on the inclined support 4. The anchor hole 22 and the anchor cable 21 pass through the pile body 19. The pile body 19 enters the surrounding rock on the right side of the pile body 19, and the anchor 15 is used to clamp the anchor cable 21 and anchor the left end of the anchor cable 21 on the inclined support 4 to prevent the anchor cable 21 from slipping or loosening when subjected to tension. The inclined support 4 is divided into two types: reinforced concrete inclined support and steel inclined support. Among them, the size of the reinforced concrete inclined support is 800 (length) * 800 (width) * 600 (height) mm, and the size of the steel inclined support is 800 (length) * 800 (width) * 400 (height) mm. When supporting the foundation pit, the pressure borne by the anchor 15 can be transmitted to the pile body 19 through the inclined support 4 to ensure the safety of the surrounding structure. However, because the anchor 15 and the inclined support 4 are both arranged on the outside of the pile body 19, after installation, multiple protrusions will be formed on the surface of the pile body 19, causing the side wall of the foundation pit to be uneven. When the outer waterproof layer is pasted on the side wall of the foundation pit, it is usually necessary to lay the protrusions flat by spraying concrete, laying brick walls, etc. These operations form a fertilizer trough filling layer with a width of 450-600mm between the pile body 19 and the outer wall of the underground main structure. This will not only increase the excavation width of the foundation pit on one side by 450-600mm, but also increase the construction cost, and extend the construction period due to the fertilizer trough filling operation, and at the same time, increase the risk of high-altitude operations. Summary of the invention

[0004] The present invention aims to provide a method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation, thereby reducing the amount of foundation pit excavation and lowering construction costs. At the same time, it can also shorten the construction period and avoid the risks of high-altitude operations caused by fertilizer trough filling operations.

[0005] To achieve the above object, the present invention adopts the following technical solution: a method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation, comprising the following steps:

[0006] S1: Tie up the steel cage;

[0007] S2: Install the inclined support on the steel cage;

[0008] S3: Fill the inside of the inclined support with filler;

[0009] S4: Put the steel cage into the pile hole, and pour the concrete pile body, and embed the inclined support and the steel cage into the pile body as a whole;

[0010] S5: excavate the foundation pit, find the pre-buried inclined support, remove the debris in the inclined support, drill the anchor hole, place the anchor cable, and grout the anchor hole;

[0011] S6: After the anchor hole grouting body reaches the specified strength, install the anchor in the inclined support, clamp the anchor cable, tension the anchor cable and seal the anchor.

[0012] The beneficial effects of this solution are as follows: (1) Since the anchor is installed in the inclined support, the inclined support is fixedly connected to the steel cage and is embedded in the interior of the pile body together with the steel cage, the problem of the raised structure formed by the traditional external inclined support and anchor is solved, the increase in foundation pit excavation caused by fertilizer trough filling is avoided, the construction cost is reduced, and at the same time, the construction period is shortened and the risk of high-altitude operations caused by fertilizer trough filling operations is avoided.

[0013] (2) Due to the reduction in the amount of excavation, this technical solution reduces the disturbance to the surrounding soil and reduces the occurrence of ground subsidence and displacement. If the subsidence and displacement are too large, it will cause damage to surrounding buildings, roads, underground pipelines, etc. At the same time, it can also reduce land occupation and cause relatively little damage to the surrounding ecological environment, reduce energy consumption, and reduce carbon emissions, which meets the requirements of sustainable development.

[0014] (3) The post-embedding method is to chisel the concrete on the surface of the pile and inside the steel cage at the location where the inclined support needs to be installed after the pile body is cast, and then cut the steel cage and install the inclined support. Therefore, it has the disadvantage of large construction workload. The present technical solution adopts the pre-embedded embedding method. When casting the pile body, the inclined support and the steel cage are embedded in the pile body together. Therefore, the construction procedure of chiseling the concrete of the pile body for installing the inclined support is saved, and the construction is convenient.

[0015] (4) In the present technical solution, since the interior of the inclined support is filled with fillers, when pouring the pile concrete, the concrete will not flow into the inclined support, thereby making the interior of the inclined support smoother, thereby facilitating the installation of the anchor.

[0016] Further, in S2, the inclined support is installed on the steel cage, including the following steps:

[0017] S2.1: Cut the installation opening for the inclined bracket at the location where the inclined bracket needs to be installed on the steel cage;

[0018] S2.2: Fix the inclined support to the steel cage at the installation opening.

[0019] The beneficial effects of this solution are as follows: this technical solution facilitates the installation of the inclined support by cutting an installation opening on the steel cage, and at the same time, since the inclined support is fixedly connected to the steel cage, the strength of the pile body at the installation position of the inclined support is increased, thereby improving the stability and reliability of the pile body.

[0020] Furthermore, the installation of the inclined support in S2 also includes S2.3, sleeved with annular reinforcing stirrups on the steel cage, and fixing the annular reinforcing stirrups on the inclined support and the steel cage.

[0021] The beneficial effects of this solution are as follows: due to the provision of annular reinforcing stirrups, this technical solution can improve the connection strength between the arc-shaped panel and the steel cage, and prevent the inclined support from being displaced during the concrete construction of the poured pile body.

[0022] Furthermore, the inclined support includes a core tube and a pressure plate, the pressure plate is fixedly connected to the inside of the core tube and coaxially arranged with the core tube, a No. 1 circular hole is provided on the pressure plate, the core tube is fixedly connected to the steel cage, and the core tube can be embedded in the pile body together with the steel cage.

[0023] The beneficial effect of this solution is that when in use, with the help of washers, the washers are set between the anchor and the pressure plate, so that the tension of the post-tensioned anchor cable can be stably transmitted to the pressure plate through the washers, and then transmitted to the core tube, and transmitted to a larger area of ​​the pile surface through the core tube, reducing local stress concentration on the pile body, avoiding excessive deformation or damage of the pile body in local areas, thereby enhancing the overall stability and reliability of the pile body.

[0024] In this technical solution, since the core tube is fixedly connected to the steel cage, the core tube and the steel cage are connected as a whole, thereby increasing the strength of the pile in the core tube area; at the same time, during the pouring of concrete for the pile body, the fluid concrete will generate a large buoyancy and lateral pressure on the inclined support buried in the pile body. By fixing the outer side of the core tube with the steel cage and adding annular reinforcing stirrups, the inclined support can be prevented from being deviated (such as floating up), thereby making the positioning of the inclined support more accurate.

[0025] Due to the provision of the No. 1 circular hole, the technical solution facilitates the drill bit to pass through the No. 1 circular hole to complete the anchor hole drilling during the anchor hole construction.

[0026] In this technical solution, since the core tube can be embedded in the pile body together with the steel cage, after the pile body is cast and formed, the core tube is completely embedded in the pile body, which solves the problem of the raised structure formed by the traditional external inclined support and anchor, avoids the increase in foundation pit excavation caused by fertilizer trough filling, reduces construction costs, shortens the construction period, and avoids the risk of high-altitude operations caused by fertilizer trough filling operations.

[0027] Furthermore, the inclined support also includes an arc-shaped panel, which can fit with the outer side of the steel cage and be fixedly connected to the steel cage. The core tube is fixedly connected to the side of the arc-shaped panel close to the steel cage. The core tube can pass through the steel cage and is located inside the steel cage. The outer side of the core tube is fixedly connected to the steel cage. The arc-shaped panel is provided with a No. 2 circular hole connected to the core tube.

[0028] The beneficial effect of this solution is that due to the setting of the curved panel, the pressure borne by the anchor can be distributed to a larger area on the pile surface, reducing local stress concentration on the pile body, avoiding excessive deformation or damage of the pile body in local areas, thereby enhancing the overall stability and reliability of the pile body.

[0029] Due to the setting of the curved panel, the tension of the post-tensioned anchor cable can be transmitted to the core tube through the pressure plate, and then to the curved panel, and effectively transmitted to the outside of the steel cage through the curved panel, and act on the surface of the pile body. In this way, the force transmission mechanism between the inclined support and the pile body is consistent with that of the traditional external anchor, which can ensure the safety of the enclosure structure.

[0030] Furthermore, the free end of the core tube is arranged to be tilted downward, and the angle between the core tube and the vertical direction is between 15° and 25°.

[0031] The beneficial effects of this solution are as follows: since the free end of the core tube is tilted downward and the angle between the core tube and the vertical direction is between 15° and 25°, the inclined support is close to the center side of the pile body, presenting a layout with a narrow lower part and a wide upper part. During the concrete construction of the cast-in-place pile body, it can effectively avoid the concrete pouring conduit being tightly fitted with the inclined support under the squeezing action of liquid concrete, causing the concrete conduit connecting flange to be stuck by the inclined support and unable to be pulled up, thereby delaying the concrete pouring and preventing the risk of the pile body being scrapped.

[0032] Furthermore, a pressure pad is provided between the anchor and the pressure plate. The side of the pressure pad close to the pressure plate is in contact with the pressure plate, and the side of the pressure pad close to the anchor is in contact with the anchor. The outer diameter of the pressure pad is smaller than the inner diameter of the core tube. A No. 3 circular hole is provided at the center of the pressure pad for the anchor cable to pass through, and the diameter of the No. 3 circular hole is smaller than the outer diameter of the anchor.

[0033] The beneficial effects of this solution are as follows: in order to facilitate the drilling construction of the anchor hole, the diameter of the No. 1 circular hole is usually larger than the outer diameter of the anchor. Therefore, a pressure pad is arranged between the anchor and the pressure plate to facilitate the transfer of the pressure on the anchor to the pressure plate, and then to the core tube, the curved panel and the pile body in turn through the pressure plate, thereby achieving the dispersion of the pressure on the anchor.

[0034] Furthermore, an angle adjustment unit is provided between the anchor and the pressure plate, and the angle adjustment unit can adjust the angle of the anchor.

[0035] The beneficial effect of this solution is that due to the setting of the angle adjustment unit, this technical solution can adjust the installation angle of the anchor, thereby adjusting the construction error and ensuring that the installation angle of the anchor cable is not affected.

[0036] Furthermore, the angle adjustment unit includes an adjusting bottom plate and an adjusting top plate, the outer diameters of the adjusting bottom plate and the adjusting top plate are both smaller than the inner diameter of the core tube, the side of the adjusting bottom plate close to the pressure plate is a plane and fits with the surface of the pressure plate, the side of the adjusting bottom plate close to the adjusting top plate is a convex spherical surface, and the side of the adjusting top plate close to the adjusting bottom plate is a concave spherical surface, the convex spherical surface and the concave spherical surface are in contact with each other, and the adjusting top plate can slide along the convex spherical surface, the side of the adjusting top plate close to the anchor is a plane and fits with the surface of the anchor, and the center position of the adjusting bottom plate and the adjusting top plate are both provided with a No. 4 circular hole for the anchor cable to pass through, the diameter of the No. 4 circular hole is smaller than the diameter of the No. 1 circular hole, and the diameter of the No. 4 circular hole is smaller than the outer diameter of the anchor.

[0037] The beneficial effects of this solution are as follows: during the construction of the pile body concrete, the flowing concrete will form a large buoyancy on the inclined support buried in the pile body. If the inclined support and the steel cage are not firmly fixed, it is very easy to cause the inclined support to be displaced (such as the inclined support floating up). When the inclined support is displaced, the adjusting top plate is rotated to make the adjusting top plate rotate around the convex spherical surface of the adjusting bottom plate. At the same time, the anchor is driven to rotate along the center of the anchor hole, thereby adjusting the construction error and ensuring that the anchor cable angle is not affected.

[0038] Since the diameter of the No. 4 circular hole in this technical solution is smaller than the outer diameter of the anchor, it is convenient for the anchor to fit with the adjustment top plate and can stably transfer the pressure borne by the anchor to the pressure plate.

[0039] After the adjusting bottom plate and the adjusting top plate are adjusted to the appropriate angles, the anchor, the adjusting top plate and the adjusting bottom plate are pressed against the pressure plate by the pressure brought by the anchor cable tension, which automatically fixes the anchor, the adjusting top plate and the adjusting bottom plate, and has the advantage of convenient operation.

[0040] Furthermore, a positioning cylinder is detachably connected to the pressure plate, one end of the positioning cylinder away from the steel cage is inserted into the side wall of the pile hole, and the interior of the positioning cylinder is also filled with fillers.

[0041] The beneficial effects of this solution are as follows: In the actual construction process, the pile hole is usually slightly larger than the designed size, mainly to facilitate the installation of the steel cage. However, this will cause the inclined support to be buried relatively deep in the pile body. When excavating the foundation pit, the position of the inclined support is difficult to find. When it is necessary to break the surface of the pile body to dig out the inclined support, the volume of the pile body to be broken will often increase, thereby increasing the degree of damage to the pile body and ultimately reducing the overall structural stability of the pile body.

[0042] In actual construction, in order to avoid the collapse of the borehole, a layer of mortar is usually applied to the side wall of the borehole to form a protective wall. When installing the positioning tube, one end of the positioning tube is inserted into the No. 1 circular hole, and the other end is inserted into the side wall of the pile hole. When inserting the positioning tube into the side wall of the pile hole, it is necessary to first break the protective wall at the installation position of the positioning tube, and then insert the positioning tube into the side wall of the pile hole. Since the surrounding rock is generally weak when the pile body and anchor cable are used for joint support, the positioning tube can be smoothly inserted into the side wall of the pile hole (that is, the surrounding rock).

[0043] Due to the setting of the annular reinforcing stirrups, this technical solution can ensure the gap between the steel cage and the side wall of the pile hole, thereby ensuring that the inclined support does not deviate in the pile hole, and realizing the secondary positioning of the inclined support. The advantages of doing so are: on the one hand, it can ensure that the position of the inclined support in the pile body is more accurate and stable. After the secondary positioning, the inclined support will not undergo a large displacement during the concrete pouring process, thereby ensuring the integrity and reliability of the pile structure. In the subsequent construction process, such as foundation pit excavation and other links, the position of the inclined support can be found more accurately, reducing unnecessary pile breaking caused by inaccurate positioning, reducing the degree of damage to the pile body, and thus maintaining the overall structural stability of the pile body. On the other hand, the secondary positioning of the annular reinforcing stirrups helps to improve construction efficiency. During the construction process, accurate positioning can reduce the time and labor costs consumed by position adjustment. At the same time, the clear position of the inclined support also facilitates the subsequent processes, making the entire construction process smoother and more efficient.

[0044] After finding the inclined support, part of the annular reinforcing stirrups needs to be cut off to facilitate the installation of the angle adjustment unit, anchor and pressure pad. The filler inside the inclined support is generally made of flexible materials such as foam plastics, and the hardness of the flexible material is usually lower than the material hardness of the positioning tube.

[0045] The two positioning objects of the inclined support are different. The first positioning is to fix the inclined support on the steel cage, and its purpose is to use the steel cage as an anchor to stabilize the relative position of the inclined support and the steel cage; the second positioning is to fix the inclined support on the side wall of the pile hole through the positioning cylinder, and its purpose is to use the side wall of the pile hole as an anchor to determine the relative position of the inclined support and the steel cage, thereby achieving a good effect of double positioning.

[0046] In fact, the second fixing method is relatively less affected by the offset of concrete pouring. Specifically, during the concrete pouring process, the concrete enters the steel cage through the conduit, and the conduit needs to be buried about 5m below the poured concrete surface. At this time, the concrete emerges from the bottom of the conduit upward, and the impact force on the steel cage is relatively strong. Then, after the concrete is buffered by the steel cage, it fills the position between the steel cage and the side wall of the pile hole. Due to the small space at this position, it is not convenient for operators to directly insert a vibrating rod for vibration. Most of the time, the concrete in the steel cage is vibrated to promote the flow of concrete to the outside of the steel cage to make the concrete more compact. Therefore, the second fixing of the inclined support is achieved by inserting the positioning tube into the side wall of the pile hole. Its main fixing position is on the side wall of the pile hole, which is less affected by the concrete pouring, thereby ensuring the position accuracy of the inclined support, and then ensuring that the tensioning direction of the anchor cable is consistent with the design to achieve the best force effect.

[0047] In addition, the annular reinforcement stirrups can ensure that the steel cage maintains a certain distance from the side wall of the borehole, thereby meeting the requirements for the thickness of the protective layer of the steel cage in the specification. This can prevent the steel cage from shaking and approaching the side wall of the borehole during the concrete pouring process, thereby avoiding the situation where the local concrete protective layer is too thin, and ensuring the durability of the steel cage. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the existing foundation pit supporting structure of the present invention;

[0049] Figure 2 It is a flow chart of a method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to the present invention;

[0050] Figure 3 A three-dimensional diagram of a cylindrical anchor structure for reducing the amount of foundation pit excavation in Example 1 of the present invention;

[0051] Figure 4 A three-dimensional diagram of the coordination between the oblique support and the anchor in Example 1 of the present invention;

[0052] Figure 5 It is an exploded view of the cooperation between the oblique support and the anchor in Example 1 of the present invention;

[0053] Figure 6 A three-dimensional diagram of the angle adjustment unit in Embodiment 2 of the present invention;

[0054] Figure 7 Schematic diagram of the angle adjustment unit in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0055] The following is further described in detail through specific implementation methods:

[0056] The figure marks in the drawings of the specification include: steel cage 1, main steel bar 2, annular stirrups 3, oblique support 4, curved panel 5, annular reinforcing stirrups 6, core tube 7, No. 2 circular hole 8, external stiffening rib 9, pressure plate 10, No. 1 circular hole 11, internal stiffening rib 12, pressure pad 13, No. 3 circular hole 14, anchor 15, adjusting bottom plate 16, adjusting top plate 17, No. 4 circular hole 18, pile body 19, through hole 20, anchor cable 21, anchor hole 22.

[0057] Example 1

[0058] The structure of the cylindrical anchor used to reduce the amount of foundation pit excavation is basically as follows Figure 1-5 shown.

[0059] like Figure 3 The cylindrical anchor 15 structure shown for reducing the amount of foundation pit excavation comprises an inclined support 4 and an anchor 15 . The inclined support 4 is welded to the steel cage 1 . In this embodiment, the inclined support 4 is a steel inclined support 4 .

[0060] like Figure 4-5As shown, the inclined support 4 includes an arc panel 5, a core tube 7 and a pressure plate 10. Specifically, the right side of the arc panel 5 is fitted with the outer side of the steel cage 1 and welded to the steel cage 1. The steel cage 1 at the installation position of the inclined support 4 is sleeved with an annular reinforcing hoop 6, and the annular reinforcing hoop 6 is welded to the steel cage 1 and the arc panel 5. The core tube 7 is a cylindrical structure with openings on both the left and right ends. The core tube 7 is welded to the right side of the arc panel 5. The left side of the arc panel 5 is provided with a No. 2 circular hole 8 connected to the core tube 7. The right end of the core tube 7 can pass through the steel cage 1 and is inside the steel cage 1. The outer side of the core tube 7 is welded to the steel cage 1, and then the core tube 7 and the steel cage 1 are connected to form a whole. The right end of the core tube 7 is arranged to be tilted downward, and the angle between the core tube 7 and the vertical direction is between 15°-25°. A plurality of external stiffening ribs 9 are welded circumferentially on the outer side surface of the core tube 7. The external stiffening ribs 9 are triangular in shape, and the left side of the external stiffening ribs 9 is welded on the arc panel 5; the pressure plate 10 is welded inside the core tube 7 and is coaxially arranged with the core tube 7. A No. 1 circular hole 11 is opened at the center position of the pressure plate 10, and the aperture of the No. 1 circular hole 11 is larger than the outer diameter of the anchor 15. A plurality of internal stiffening ribs 12 are welded along the circumference of the inside of the core tube 7. The internal stiffening ribs 12 are also triangular in shape. The internal stiffening ribs 12 are located on the right side of the pressure plate 10, and the left side thereof is welded to the right side of the pressure plate 10. A pressure pad 13 is provided between the anchor 15 and the pressure plate 10. The side of the pressure pad 13 close to the pressure plate 10 is in contact with the pressure plate 10, and the side of the pressure pad 13 close to the anchor 15 is in contact with the anchor 15. The outer diameter of the pressure pad 13 is smaller than the inner diameter of the core tube 7. A No. 3 circular hole 14 for the anchor cable 21 to pass through is provided at the center of the pressure pad 13. The diameter of the No. 3 circular hole 14 is smaller than the outer diameter of the anchor 15. The pressure transmission energy borne by the anchor 15 can be transmitted to the pressure plate 10 through the pressure pad 13. The anchor 15 is arranged on the left side of the pressure plate 10 and is located inside the core tube 7. The anchor 15 is used to clamp the anchor cable 21 or the steel strand to prevent the anchor cable 21 or the steel strand from slipping or loosening when subjected to tension, and to evenly transfer the tension formed by the tensioned anchor cable 21 to the pressure plate 10. In this embodiment, the anchor 15 adopts the existing clip anchor 15, and the appropriate size can be selected according to actual needs. The clip anchor 15 is a prior art and will not be described again here; the angle between the core tube 7 and the vertical direction is 23°.

[0061] A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation, such as Figure 2 As shown, the following steps are included:

[0062] S1: Tie up the steel cage 1 and weld the connection points of the main steel bars 2 and the annular stirrups 3 together; specifically, Figure 3As shown, the steel cage 1 is composed of a plurality of main steel bars 2 and a plurality of annular stirrups 3. The main steel bars 2 are evenly distributed inside the annular stirrups 3 along the circumference thereof and are welded to the annular stirrups 3. The annular stirrups 3 are evenly spaced along the longitudinal direction of the main steel bars 2.

[0063] S2: Install the inclined support 4 on the steel cage 1;

[0064] S2.1: Cut an installation opening for the inclined bracket 4 at a position where the inclined bracket 4 is to be installed on the steel cage 1;

[0065] S2.2: The inclined support 4 is fixedly connected to the steel cage 1 at the installation opening. Specifically, the arc-shaped panel 5 and the core tube 7 are welded to the steel cage 1 .

[0066] S2.3: Annular reinforcing stirrups 6 are sleeved on the steel cage 1 , and the annular reinforcing stirrups 6 are welded to the inclined support 4 and the steel cage 1 .

[0067] S3: Filling the interior of the inclined support 4 with a filler, wherein the filler is a foam plastic;

[0068] S4: Put the steel cage 1 into the pile hole, and pour the concrete pile body 19, the inclined support 4 and the steel cage 1 are integrally embedded in the pile body 19; the hoisting of the steel cage 1 and the pouring of the concrete of the pile body 19 are both prior arts, and will not be described in detail here;

[0069] S5: excavate the foundation pit, find the pre-buried inclined support 4, remove the debris in the inclined support 4, drill the anchor hole 22, place the anchor cable 21, and grout the anchor hole 22;

[0070] S6: After the grouting body of the anchor hole 22 reaches the specified strength, the anchor 15 and the pressure pad 13 are installed in the core tube 7, and the anchor cable 21 is clamped, the anchor cable 21 is tensioned and the anchor is sealed.

[0071] Example 2

[0072] What is different from the first embodiment is that the pressure plate 13 is replaced by an angle adjustment unit, that is, an angle adjustment unit is arranged between the pressure plate 10 and the anchor 15 , and the angle adjustment unit can adjust the angle of the anchor 15 .

[0073] Specifically, Figure 6-7As shown, the angle adjustment unit includes an adjusting bottom plate 16 and an adjusting top plate 17. The outer diameters of the adjusting bottom plate 16 and the adjusting top plate 17 are both smaller than the inner diameter of the core tube 7. The right side surface of the adjusting bottom plate 16 is a plane, which fits tightly with the surface of the pressure plate 10. The left side surface of the adjusting bottom plate 16 is a convex spherical surface, and the right side surface of the adjusting top plate 17 is a concave spherical surface. The convex spherical surface and the concave spherical surface are in contact with each other, and the adjusting top plate 17 can slide along the convex spherical surface. The left side surface of the adjusting top plate 17 is a plane, which fits tightly with the surface of the anchor 15. The center positions of the adjusting bottom plate 16 and the adjusting top plate 17 are both provided with a No. 4 circular hole 18 for the anchor cable 21 or the steel strand to pass through. The diameter of the No. 4 circular hole 18 is smaller than the outer diameter of the anchor 15. Since the diameter of the No. 4 circular hole 18 is smaller than the outer diameter of the anchor 15, it is convenient to make the anchor 15 fit with the adjusting top plate 17, and the pressure borne by the anchor 15 can be stably transmitted to the pressure plate 10.

[0074] During the concrete construction of the pile body 19, the fluid concrete will form a large buoyancy on the inclined support 4 buried in the pile body 19. If the inclined support 4 is not firmly fixed to the steel cage 1, it is very easy to cause the inclined support 4 to be displaced (such as the inclined support 4 floating up). When the inclined support 4 is displaced, the adjusting top plate 17 is rotated to make the adjusting top plate 17 rotate around the convex spherical surface of the adjusting bottom plate 16. At the same time, the anchor 15 is driven to rotate along the center of the anchor hole 22, thereby adjusting the construction error and ensuring that the installation angle of the anchor cable 21 is not affected.

[0075] Example 3

[0076] On the basis of Example 1 or Example 2, a positioning cylinder is inserted on the pressure plate 10, and the end of the positioning cylinder away from the steel cage 1 is inserted into the side wall of the pile hole. The interior of the positioning cylinder is also filled with a filler. The positioning cylinder is made of PVC material, and the filler is a flexible material. In this embodiment, the filler is foam plastic. Due to the setting of the positioning cylinder, it is convenient to locate the installation position of the inclined support 4. At the same time, when the anchor cable 21 is used to support the foundation pit, it is convenient to find the installation position of the inclined support 4, thereby improving the construction efficiency.

[0077] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation, characterized in that: The following steps are involved: S1: Tie up the steel cage; S2: Install the inclined support on the steel cage. The inclined support includes a core tube and a pressure plate. The pressure plate is fixedly connected to the inside of the core tube and is coaxially arranged with the core tube. A No. 1 circular hole is arranged in the pressure plate. The core tube is fixedly connected to the steel cage, and the core tube can be integrally embedded in the pile body with the steel cage. S3: Fill the inside of the inclined support with filler; S4: Put the steel cage into the pile hole, and pour the concrete pile body, and embed the inclined support and the steel cage into the pile body as a whole; S5: excavate the foundation pit, find the pre-buried inclined support, remove the debris in the inclined support, drill the anchor hole, place the anchor cable, and grout the anchor hole; S6: After the anchor hole grouting body reaches the specified strength, install the anchor in the inclined support, clamp the anchor cable, tension the anchor cable and seal the anchor.

2. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 1, characterized in that: In S2, the inclined support is installed on the steel cage, including the following steps: S2.1: Cut the installation opening for the inclined bracket at the location where the inclined bracket needs to be installed on the steel cage; S2.2: Fix the inclined support to the steel cage at the installation opening.

3. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 2, characterized in that: The installation of the inclined support in S2 also includes S2.3, sleeved with annular reinforcing stirrups on the steel cage, and fixing the annular reinforcing stirrups on the inclined support and the steel cage.

4. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 3, characterized in that: The inclined support also includes an arc-shaped panel, which can fit with the outer side of the steel cage and be fixedly connected to the steel cage. The core tube is fixedly connected to the side of the arc-shaped panel close to the steel cage. The core tube can pass through the steel cage and is inside the steel cage. The outer side of the core tube is fixedly connected to the steel cage. The arc-shaped panel is provided with a No. 2 circular hole connected to the core tube.

5. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 4, characterized in that: The free end of the core tube is arranged to be tilted downward, and the angle between the core tube and the vertical direction is between 15° and 25°.

6. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 5, characterized in that: A pressure pad is provided between the anchor and the pressure plate. The side of the pressure pad close to the pressure plate is in contact with the pressure plate, and the side of the pressure pad close to the anchor is in contact with the anchor. The outer diameter of the pressure pad is smaller than the inner diameter of the core tube. A No. 3 circular hole is provided at the center of the pressure pad for the anchor cable to pass through, and the diameter of the No. 3 circular hole is smaller than the outer diameter of the anchor.

7. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 5, characterized in that: An angle adjustment unit is provided between the anchor and the pressure plate, and the angle adjustment unit can adjust the angle of the anchor.

8. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to claim 7, characterized in that: The angle adjustment unit includes an adjusting bottom plate and an adjusting top plate. The outer diameters of the adjusting bottom plate and the adjusting top plate are both smaller than the inner diameter of the core tube. The side of the adjusting bottom plate close to the pressure plate is a plane and fits with the surface of the pressure plate. The side of the adjusting bottom plate close to the adjusting top plate is a convex spherical surface, and the side of the adjusting top plate close to the adjusting bottom plate is a concave spherical surface. The convex spherical surface and the concave spherical surface are in contact with each other, and the adjusting top plate can slide along the convex spherical surface. The side of the adjusting top plate close to the anchor is a plane and fits with the surface of the anchor. The center position of the adjusting bottom plate and the adjusting top plate is provided with a No. 4 circular hole for the anchor cable to pass through. The diameter of the No. 4 circular hole is smaller than the diameter of the No. 1 circular hole, and the diameter of the No. 4 circular hole is smaller than the outer diameter of the anchor.

9. A method for pre-embedding a cylindrical anchor structure for reducing the amount of foundation pit excavation according to any one of claims 6 or 8, characterized in that: A positioning cylinder is detachably connected to the pressure plate, one end of the positioning cylinder away from the steel cage is inserted into the side wall of the pile hole, and the interior of the positioning cylinder is also filled with fillers.

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