Rotary jet grouting type anchor rod structure with bag type expanded head
The cement soil shell and anchor block are formed through the rotary grouting process, which solves the problems of difficult insertion and insufficient friction in the construction of bladder-type enlarged head anchor rods, improves the pull-out bearing capacity and construction efficiency, and expands the scope of application.
Patent Information
- Application Number
- CN202422627580.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2034-10-30
AI Technical Summary
During construction, the bladder-type enlarged head anchor has the problems of difficulty in pushing the bladder into the ground, low friction and adhesion with the underground soil, which affects the pull-out bearing capacity, and difficulty in cleaning the soil in the anchor hole, which makes construction complicated and limits its scope of use.
The anchor hole is formed by the rotary jet grouting process and the supporting force of the cement soil is utilized. The anchor assembly is inserted into the anchor hole through the rotary jet grouting drill rod to form a cement soil shell to increase the friction force. Cement slurry is injected into the bladder to form an anchor block to enhance the connection strength between the bladder and the soil. At the same time, the rotation of the rotary jet grouting drill rod is used to ensure the positioning and advancement of the anchor assembly.
The pull-out bearing capacity of the bladder-type enlarged head anchor is improved, the problems of difficulty in inserting the bladder bag and insufficient friction are solved, the stability and application range of the anchor structure are enhanced, and the construction process is simplified.
Smart Images
Figure CN223410156U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a rotary grouting type anchor rod structure with a sac-type enlarged head. Background Art
[0002] The bladder-type enlarged head anchor rod is a structural form of the enlarged head anchor rod. It is used in many fields because it can squeeze the surrounding soil during construction and the bladder can resist the invasion of external corrosive substances.
[0003] During the construction of the bladder-type enlarged head anchor rod, a drilling machine is first used to adopt dry construction to form the anchor rod hole, and then part of the anchor rod hole is enlarged to form the enlarged head cavity. The anchor rod steel structure is placed into the anchor rod hole, and finally cement slurry is injected into the bladder and the anchor rod hole. After the cement slurry solidifies and reaches the set strength, the anchor rod steel structure is tensioned to generate prestress.
[0004] In actual construction, the soil in the anchor hole cannot be completely cleaned, especially a certain amount of soil will remain in the enlarged head cavity, and in the process of the anchor steel structure entering the anchor hole, due to the contact of the anchor steel structure and the collapse of some anchor holes themselves, there is more soil in the anchor hole, and the bag structure is difficult to push in. When grouting into the bag, the bag cannot be completely opened, which affects the outer diameter of the bag-type enlarged head and reduces the pull-out bearing capacity of the bag-type enlarged head anchor.
[0005] In addition, due to the small friction and adhesion between the bladder and the underground soil, the anchor rod mainly relies on the end face resistance of the bladder-type enlarged head to improve the pull-out bearing capacity, which limits the scope of use of the bladder-type enlarged head anchor rod structure. Utility Model Content
[0006] In order to solve the problems in the prior art of difficulty in inserting the bladder bag into the anchor hole, as well as the low friction and bonding force between the bladder bag and the underground soil, which affect the pull-out bearing capacity of the bladder-type enlarged head anchor structure, the present application proposes a rotary grouting anchor structure with a bladder-type enlarged head, which includes an anchor assembly extending into the anchor hole and cement soil wrapped around the anchor assembly. The anchor hole is formed by a rotary grouting process;
[0007] The anchor assembly comprises an anchor cable group and two anchor plate assemblies, the two anchor plate assemblies are respectively a first anchor plate assembly and a second anchor plate assembly, the anchor cable group has a plurality of anchor cables, the plurality of anchor cable groups are arranged at intervals around a central axis, the two ends of each anchor cable are respectively formed with an anti-pullout end and a tensioning end, the anti-pullout end is located in the enlarged head cavity of the anchor cable hole, and the tensioning end extends outward from the anchor cable hole; the two anchor plate assemblies are arranged at intervals along the extension direction of the anchor cable hole, and the two anchor plate assemblies are both fixed on each anchor cable, wherein the second anchor plate assembly is located on the side of the first anchor plate assembly away from the tensioning end, and the anti-pullout end of each anchor cable is fixed on the two anchor plate assemblies; one end of the bladder is open and formed as a slurry inlet, and the other end of the bladder is closed, and the slurry inlet is sealed and fixed to the first anchor plate assembly; an anchor block formed by cement slurry is provided in the bladder;
[0008] A central hole is provided on the first anchor plate assembly, and the jet grouting drill rod can be passed through the central hole in a sealed manner and then pressed against the second anchor plate assembly to deliver the anchor rod assembly into the anchor rod hole;
[0009] The first anchor plate assembly is provided with a grouting pipe hole and an exhaust pipe hole. The grouting pipe hole is used to insert a grouting pipe, and the exhaust pipe hole is used to insert an exhaust pipe. When one end of the grouting pipe and the exhaust pipe are respectively inserted into the grouting pipe hole and the exhaust pipe hole, the other ends of the grouting pipe and the exhaust pipe each extend outward from the anchor rod hole. When the grouting pipe is inserted into the grouting pipe hole, a first sealing ring is installed between the grouting pipe and the grouting pipe hole. When the exhaust pipe is inserted into the exhaust pipe hole, a second sealing ring is installed between the exhaust pipe and the exhaust pipe hole. When the grouting pipe and the exhaust pipe are respectively inserted into the grouting pipe hole and the exhaust pipe hole, they can communicate with the inner cavity of the bladder bag.
[0010] In the present application, the anchor hole is formed using a rotary jet grouting method. Cement-soil, formed by mixing cement slurry with soil, remains within the anchor hole. The supporting force of the cement-soil prevents the anchor hole from collapsing. Furthermore, during construction of the anchor hole, the cement slurry seeps outward into the soil surrounding the anchor hole, compacting it and increasing its strength, thus effectively preventing the anchor hole from collapsing. When injecting cement slurry into the bladder bag to form the anchor block, this process must be completed before the cement-soil in the anchor hole has initially set, thereby utilizing the fluidity of the cement-soil. The cement-soil in the anchor hole forms a cement-soil shell around the bladder bag, bonding the external soil to the bladder bag. This shell enhances the connection strength between the bladder bag and the underground soil, thereby increasing the friction between the bladder-type enlarged head and the underground soil, and improving the pullout bearing capacity of the anchor structure. This avoids the drawback of the prior art, where the friction between the bladder-type enlarged head and the underground soil is low, and the pullout bearing capacity is primarily increased by relying on the end resistance of the bladder-type enlarged head. The two anchor plate assemblies are used to improve the connection strength between the anchor rod assembly and the anchor block.
[0011] In existing construction, the anchor rod assembly is manually pushed into the anchor rod hole using fine-rolled threaded steel bars, which is a static press-in method. Since the fine-rolled threaded steel bars are slender and have a small pushing force, if there is a lot of crushed soil remaining in the anchor rod hole, it cannot be pushed in. The anchor rod assembly can only be pulled out and the anchor rod hole can be cleaned again. During the construction, the hole collapse phenomenon will occur during the cleaning process, and it is often necessary to clean it repeatedly before the anchor rod assembly can be inserted to the set depth. In this application, the anchor rod assembly is inserted into the anchor rod hole using a rotary jet drill rod, which has a large thrust and can overcome the resistance of the cement soil in the anchor rod hole. In addition, when the rotary jet drill rod pushes the anchor rod assembly forward, it needs to keep rotating, so the anchor rod assembly has better positioning ability.
[0012] Furthermore, one end of the bladder away from the tensioning end is sealingly fixed to the second anchor plate assembly, and the second anchor plate assembly closes the end of the bladder away from the tensioning end; or one end of the bladder away from the tensioning end is sealingly fixed to the second anchor plate assembly, and a guide cap is fixedly installed on the side of the second anchor plate assembly away from the tensioning end, and a slurry hole connecting the guide cap and the bladder is provided on the second anchor plate assembly, and the guide cap and the second anchor plate assembly jointly close the end of the bladder away from the tensioning end.
[0013] In actual construction, the guide cap can be installed or eliminated as needed. In this design, when the guide cap is not installed, the second anchor plate assembly is required to overcome the resistance of the cement soil in the anchor hole during the insertion of the anchor assembly into the anchor hole. The resistance will be slightly greater than when the guide cap is installed, but some structural parts will be reduced.
[0014] Furthermore, the end of the bladder, which is away from the tensioning end, is closed, and the second anchor plate assembly is located within the bladder. In this design, the bladder is an open-ended bag, which is more convenient to install. During construction, a guide cap can be installed on the side of the second anchor plate assembly away from the first anchor plate assembly. When the anchor rod assembly is inserted into the anchor rod hole, the bladder will fit on the guide, reducing the pushing resistance of the anchor rod assembly.
[0015] Specifically, to ensure that each anchor plate assembly remains stably on the anchor cable and to avoid damage to the anchor cable, each anchor plate assembly includes an anchor plate and an extrusion plate. For each anchor cable, a through-hole anchor hole is provided on the anchor plate. The end of the anchor hole facing away from the tensioning end is formed into a conical hole with the smaller end facing the tensioning end. A clip group is arranged in the conical hole. The extrusion plate is located on the side of the anchor plate facing away from the tensioning end. A locking bolt connects the extrusion plate to the anchor plate, and the extrusion plate tightly squeezes the clips in the clip group into the conical hole, securing the anchor cable to the anchor plate. The clip-type anchor is a conventional anchor for anchor cables. This method can avoid the use of welding or other methods that affect the strength of the anchor cable to install the anchor plate assembly.
[0016] Furthermore, corresponding to each anchor cable, an extrusion tube is provided between the anchor plate and the extrusion plate of the same anchor plate assembly. The extrusion tube is sleeved on the corresponding anchor cable, and the two ends of the extrusion tube are respectively pressed against the clamping piece and the extrusion plate.
[0017] In actual construction, the clip may be completely accommodated in the conical hole. In this case, the clamping plate alone cannot press the clip tightly against the conical hole, which can easily lead to insufficient locking force of the clip on the anchor cable. As a result, the anchor cable may fall out of the anchor hole during subsequent prestressing, and prestressing cannot be completed. Using a compression tube can eliminate this problem and ensure that the clip can tightly lock the anchor cable to the lower anchor part.
[0018] Furthermore, a cement-soil expansion head is provided on the side of the bladder facing the tensioning end. The diameter of the cement-soil expansion head is larger than that of the free section and is connected to the bladder. During the formation of the cement-soil expansion head, cement slurry diffuses outward into the surrounding soil, increasing the connection strength between the cement-soil expansion head and the underground soil, thereby improving the stability of the cement-soil expansion head underground. The cement-soil expansion head and the bladder expansion head together form the expansion head section of the anchor structure, enhancing the stability of the bladder expansion head underground and expanding the range of its use.
[0019] Specifically, to ensure the stability of the cement soil enlarged head underground, the outer diameter of the cement soil enlarged head is 0.8-1.2 times the outer diameter of the anchor block.
[0020] The construction method of the rotary grouting anchor structure described in any one of the above items specifically comprises the following steps:
[0021] (1) using a jet grouting drill rod to drill an anchor hole and forming an enlarged head cavity at a set position; when drilling the anchor hole, spraying a first cement slurry outward through the jet grouting drill rod, and the first cement slurry forms cement soil with the soil;
[0022] (2) Using a jet grouting drill pipe, insert the anchor assembly carrying the grouting pipe and the exhaust pipe into the anchor hole, and position the bag in the expanded head cavity;
[0023] (3) injecting the second cement slurry into the bladder through the grouting pipe to form a bladder-type enlarged head, and the air in the bladder is discharged outward through the exhaust pipe; during the process of injecting the second cement slurry into the bladder, the jet grouting drill rod needs to be always inserted in the center hole of the first anchor plate assembly to ensure the grouting pressure in the bladder;
[0024] (4) injecting the third cement slurry into the common anchoring section and the free section;
[0025] (5) When the slurry in the anchor hole solidifies and reaches the set strength, the anchor cable is tensioned and locked.
[0026] The jet grouting drill rod keeps rotating during the process of inserting the rod assembly into the anchor hole.
[0027] In step (1), when drilling the anchor hole, first use a grouting pressure of 10-15MPa to form the hole, and then use a grouting pressure of 25-35MPa to form the enlarged head cavity; the water-cement ratio of the first cement slurry is 1.0-1.5; in step (4), the grouting pressure in the ordinary anchoring section and the free section is 10-15MPa, and the water-cement ratio of the third cement slurry is 1.0-1.5. The third cement slurry is used to form the cement soil enlarged head. When constructing the cement soil enlarged head, the grouting pressure is 25-35MPa; when the rotary jet drill rod forms the cement soil enlarged head, the rotary jet drill rod reciprocates and sprays at least twice. In step (3), when injecting the second cement slurry into the bag, the grouting pressure is 4-8MPa, and the water-cement ratio of the second cement slurry is 0.4-0.6. In this application, the water-cement ratio of each cement slurry is the weight ratio of water to cement. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 It is a structural diagram of an embodiment of the present application.
[0029] Figure 2 yes Figure 1 Enlarged view of part A.
[0030] Figure 3 yes Figure 2 Magnified view of part B.
[0031] Figure 4 yes Figure 2 Magnified view of part C.
[0032] Figure 5 This is the state diagram of the bag before grouting.
[0033] Figure 6 This is a second fixing diagram of the bladder on the first anchor plate assembly.
[0034] Figure 7 This is the second installation diagram of the bladder.
[0035] Figure 8 yes Figure 7 Magnified view of part D. DETAILED DESCRIPTION
[0036] The following describes the structure of a rotary grouting anchor rod with a bladder-type enlarged head.
[0037] Example 1
[0038] See also Figures 1-4Along its length, the jet-jet anchor structure comprises an enlarged head section 201, a conventional anchoring section 202, and a free section 203, which are sequentially connected. The enlarged head section and the conventional anchoring section are collectively referred to as the anchoring section, and the conventional anchoring section and the free section have approximately the same diameter. In this embodiment, the jet-jet anchor structure is inclined. It is understood that in other embodiments, the jet-jet anchor structure can also be vertical or horizontal. In actual construction, there are no special requirements for the extension direction of the jet-jet anchor structure.
[0039] The jet-jet anchor structure includes an anchor assembly 100 inserted into an anchor hole 200 and cement soil wrapped around the anchor assembly 100. The cement soil is not shown in the accompanying drawings. The anchor hole 200 is formed using a jet-jet process. The anchor assembly 100 includes an anchor cable group and a bladder 11. The anchor cable group includes a plurality of anchor cables 10, which are spaced apart around a central axis. Each anchor cable 10 has two ends formed into a pull-out end 101 and a tensioning end 102, respectively. The pull-out end 101 is located within the enlarged head cavity 220 of the anchor hole 200, while the tensioning end 102 extends outward from the anchor hole 200. The bladder 11 is fixed to the pull-out end 101 and located within the enlarged head cavity 220 of the anchor hole 200. An anchor block 210 formed of cement slurry is contained within the bladder 11. The anchor block and the bladder together form a bladder-type enlarged head.
[0040] The outer surface of the bag is provided with a shell adjacent to the cement soil. In the present embodiment, the bag is provided with a cement soil enlarged head 230 toward the side of the tensioning end, and the cement soil enlarged head is connected to the bag. Figure 1 In the figure, in the length direction, the area of the bladder enlarging head is marked as S, and the area of the cement soil enlarging head 230 is marked as M. The bladder enlarging head and the cement soil enlarging head together form an enlarging head section 201.
[0041] In this embodiment, the outer diameter of the cement soil enlarged head is the same as the outer diameter of the anchor block. It is understood that in other embodiments, the outer diameter of the cement soil enlarged head can also be 0.8 times, 8.9 times, 1.1 times, or 1.2 times the outer diameter of the anchor block, or other multiples between 0.8 and 1.2 times.
[0042] In this embodiment, two anchor disc assemblies are fixedly installed on the anchor cable group, namely a first anchor disc assembly 20 and a second anchor disc assembly 30, wherein the second anchor disc assembly 30 is located on the side of the first anchor disc assembly 20 away from the tensioning end, and the end of the bladder 11 facing the tensioning end is fixed to the first anchor disc assembly.
[0043] The two anchor plate assemblies have roughly the same structure. The first anchor plate assembly 20 includes a first anchor plate 21 and a first extrusion plate 23. For each anchor cable 10, the first anchor plate 21 is provided with a through-hole-shaped first anchor hole. The end of the first anchor hole, facing away from the tensioning end, is formed into a first conical hole 25 with the smaller end facing the tensioning end. A first clip group 26 is disposed within this first conical hole 25. The first extrusion plate 23 is located on the side of the first anchor plate facing away from the tensioning end. A first locking bolt 24 connects the first extrusion plate to the first anchor plate. The first extrusion plate tightly squeezes the clips of the first clip group 26 within the first conical hole, securing the anchor cable to the first anchor plate. To ensure the compression of the clips in the first clip group, a first extrusion tube 22 is sleeved on each anchor cable. The first extrusion tube is located between the clips of the first clip group and the first extrusion plate. The first extrusion plate is pressed against the clips of each first clip group through the first extrusion tube.
[0044] The second anchor plate assembly 30 includes a second anchor plate 31 and a second extrusion plate 33. For each anchor cable 10, a through-hole-shaped second anchor hole is provided on the second anchor plate 31. The end of the second anchor hole, facing away from the tensioning end, is formed into a second conical hole 35 with the smaller end facing the tensioning end. A second clip group 36 is disposed within the second conical hole 35. The second extrusion plate 33 is located on the side of the second anchor plate facing away from the tensioning end. A second locking bolt 34 connects the second extrusion plate to the second anchor plate. The second extrusion plate tightly squeezes the clips in the second clip group 36 within the second conical hole, securing the anchor cable to the second anchor plate. To ensure the compression of the clips in the second clip group, a second extrusion tube 32 is sleeved on each anchor cable. The second extrusion tube is located between the clips of the second clip group and the second extrusion plate. The second extrusion plate is pressed against the clips of each second clip group via the second extrusion tube.
[0045] Please continue with reference 3. In this embodiment, the end of the bladder 11 facing the tensioning end is open and forms the slurry inlet. The end of the bladder 11 facing away from the tensioning end is closed. The bladder is mounted on the end of the anchor rod assembly facing away from the tensioning end. A first clamping ring 13 is provided on the side of the first anchor plate 21 facing away from the second anchor plate assembly. The edge of the slurry inlet is tightly clamped between the first anchor plate and the first clamping ring 13. A first clamping bolt 14 passes through the first clamping ring 13 and is screwed onto the first anchor plate, sealingly securing the end of the bladder facing the tensioning end to the first anchor plate assembly. The second anchor plate assembly is accommodated within the bladder.
[0046] When securing the bladder, special seals are generally not required. Since the bladder is primarily made of organic materials such as HDPE, PVC, or PPTA, it has a certain degree of elasticity and inherently provides a strong seal. If the slurry inlet is difficult to install, a special connector can be provided at the inlet to facilitate installation. Of course, a seal can also be installed if necessary.
[0047] It is understood that in another embodiment, a guide member can be provided on the side of the second anchor assembly facing away from the first anchor assembly to reduce the resistance of the anchor assembly when inserted into the anchor hole. After the guide member is provided, the guide member is also wrapped in the sac.
[0048] It is understood that in another embodiment, the bag can be fixed to the first anchor plate assembly by a hoop method, see Figure 5 When the bag is fixed by a hoop method, an upper ring 12 adapted to the outer peripheral surface of the first anchor plate needs to be provided at the slurry inlet of the bag, and the upper hoop 18 tightly and hermetically binds the upper ring to the outer peripheral surface of the first anchor plate.
[0049] The first anchor plate 21 is provided with a grouting pipe hole 212 and an exhaust pipe hole 213. The grouting pipe hole 212 is used to insert a grouting pipe 301, and the exhaust pipe hole 213 is used to insert an exhaust pipe 302. When one end of the grouting pipe and the exhaust pipe are respectively inserted into the grouting pipe hole and the exhaust pipe hole, the other ends of the grouting pipe and the exhaust pipe extend outward from the anchor hole. The grouting pipe and the exhaust pipe are both connected to the inner cavity of the bag.
[0050] In order to improve the sealing performance, in this embodiment, a sealing ring is provided between the grouting pipe and the grouting pipe hole, and between the exhaust pipe and the exhaust pipe hole. In the accompanying drawings, the sealing ring is not shown. In the specific construction, it can be completed according to the installation of pipeline sealing rings in the existing technology, and will not be repeated.
[0051] Cement slurry can be injected into the bag through the grouting pipe to form the anchor block 210. During the process of injecting the cement slurry into the bag, the gas in the bag can be discharged from the anchor hole 200 through the exhaust pipe.
[0052] A first center hole 211 is defined in the center of the first anchor plate 21, and a through-plate hole 231 is defined in the center of the first extrusion plate 23. A second center hole 311 is defined in the center of the second anchor plate 31. The jet grouting drill rod 300 can pass through the first center hole 211 and then press against the second center hole 311, inserting the anchor rod assembly 100 into the anchor rod hole 200. The first center hole 211, through-plate hole 231, and second center hole 311 are all through holes and are coaxially arranged to facilitate the insertion of the jet grouting drill rod.
[0053] In order to avoid the inability to increase the grouting pressure when grouting into the bladder due to the gap between the rotary jet drill rod and the first center hole 211, thereby affecting the grouting effect, in this embodiment, a rubber sealing ring 214 is embedded in the inner wall of the first center hole. When the rotary jet drill rod passes through the first center hole, the rubber sealing ring 214 seals the gap between the rotary jet drill rod and the inner wall of the first center hole, thereby improving the sealing of the bladder.
[0054] Example 2
[0055] This embodiment is basically the same as embodiment 1, and the only difference is that the structure and installation method of the pouch are slightly different.
[0056] See also Figure 7 and Figure 8 In this embodiment, the end of the bladder 11 facing the tensioning end is the same as in Example 1, but the end of the bladder 11 facing away from the tensioning end is also open. For ease of description, the end of the bladder 11 facing away from the tensioning end is referred to as the open end. A second clamping ring 16 is provided on the side of the second anchor plate 31 facing the first anchor plate assembly. The edge of the open end is tightly clamped between the second anchor plate and the second clamping ring 16. A second clamping bolt 17 passes through the second clamping ring 16 and is screwed onto the second anchor plate, sealingly securing the open end of the bladder to the second anchor plate assembly. When installing the bladder, the open end needs to be secured to the second anchor plate first, and then the slurry inlet needs to be secured to the first anchor plate.
[0057] Of course, in another embodiment, the second clamping bolt 17 may be passed through the second anchoring plate and screwed onto the second clamping ring.
[0058] It is understood that in another embodiment, the fixing of the open end to the second anchor plate can also be done by a hoop. For details, please refer to the corresponding content in Example 1 and Figure 5 , no more details.
[0059] A guide cap 50 is welded to the side of the second anchor plate facing away from the first anchor plate assembly. Together, the guide cap and the second anchor plate seal the open end, effectively sealing the end of the bladder facing away from the tensioning end. To facilitate the entry of cement slurry into the inner cavity of the guide cap 50, six slurry through-holes 312 are defined on the second anchor plate, evenly spaced around the second center hole 311. A slurry passage hole 331 is also defined in the center of the second extrusion plate 33 to facilitate the entry of cement slurry into the space between the second extrusion plate 33 and the end of the guide cap. It is understood that the guide cap can also be removably mounted on the second anchor plate, hermetically secured to the second anchor plate using bolts.
[0060] It is understood that in another embodiment, the guide cap can be eliminated, and the second center hole 311 and slurry through hole 312 on the second anchor plate can be eliminated. The second anchor plate can be used to seal the open end, that is, the second anchor plate assembly seals the end of the bladder facing away from the tensioning end. To facilitate positioning of the jet grouting drill rod on the second anchor plate, a blind hole can be provided on the side of the second anchor plate facing the first anchor plate assembly. When the jet grouting drill rod delivers the anchor rod assembly 100 into the anchor rod hole 200, the head of the jet grouting drill rod is inserted into the blind hole.
[0061] The following describes the construction method of the rotary grouting anchor structure in the above-mentioned embodiments 1 and 2. The steps are as follows:
[0062] (1) The anchor hole is drilled by a jet grouting drill rod of a jet grouting drill, and an enlarged head cavity is formed at a set position. When drilling the anchor hole, a first cement slurry is sprayed outward through the jet grouting drill rod, and the first cement slurry forms cement soil with the soil.
[0063] When drilling an anchor hole, a grouting pressure of 10-15 MPa is first used to create the hole, followed by a grouting pressure of 25-35 MPa to form the enlarged head cavity; the water-cement ratio of the first cement slurry is 1.0-1.5. Specifically, in this embodiment, a grouting pressure of 12 MPa is first used to create the hole, followed by a grouting pressure of 30 MPa to form the enlarged head cavity; the water-cement ratio of the first cement slurry is 1.2.
[0064] (2) After the anchor hole is drilled, the jet grouting drill rod is pulled out of the anchor hole. The head of the jet grouting drill rod is passed through the first center hole 211 and the through-plate hole 231, and then pressed against the edge of the second center hole 311. The jet grouting drill rod is used to insert the anchor assembly with the grouting pipe and the exhaust pipe into the anchor hole, and the bag is located in the enlarged head cavity. Figure 6 At this time, under the pressure of the cement soil in the anchor hole, the bag is attached to the components of the anchor assembly. Figure 6 In the embodiment, the bladder is not attached to the components of the anchor assembly.
[0065] (3) A second cement slurry is injected into the bladder through the grouting pipe, and the air in the bladder is discharged outward through the exhaust pipe; after the second cement slurry solidifies, it forms an anchor block 210, and the anchor block and the bladder together form a bladder-type enlarged head.
[0066] During the process of injecting the second cement slurry into the bag, the rotary jet drill rod needs to be always inserted in the first center hole of the first anchor plate, and during the injection of the second cement slurry, the rotary jet drill rod is slowly pulled out, but the end of the rotary jet drill rod must be kept in the first center hole. After the injection of the second cement slurry is completed, the rotary jet drill rod is completely pulled out of the first center hole to carry out the construction of the cement soil expansion head.
[0067] When the second cement slurry is injected into the bag, the grouting pressure is 4-8 MPa, and the water-cement ratio of the second cement slurry is 0.4-0.6. Specifically in this embodiment, when the second cement slurry is injected into the bag, the grouting pressure is 5 MPa, and the water-cement ratio of the second cement slurry is 0.5.
[0068] After grouting into the bag is completed, the jet drill rod is moved outward. When the jet drill rod is separated from the bag, the third cement slurry is sprayed to form a cement soil enlarged head. The cement soil enlarged head and the bladder enlarged head together form the enlarged head section 201.
[0069] When constructing the cement soil enlarged head, the grouting pressure is 25-35 MPa, and the water-cement ratio of the third cement slurry is 1.0-1.5. Specifically in this embodiment, when forming the cement soil enlarged head, the grouting pressure is 30 MPa, and the water-cement ratio of the third cement slurry is 1.2.
[0070] When the jet grouting drill pipe forms the cement soil expansion head, the jet grouting drill pipe reciprocates and sprays at least twice. Grouting into the bag needs to be completed before the cement soil in the anchor hole completes initial setting.
[0071] (4) Inject the third cement slurry into the common anchoring section and the free section. The grouting pressure in the common anchoring section and the free section is 10-15 MPa. In this embodiment, the grouting pressure in the common anchoring section and the free section is 12 MPa.
[0072] (5) When the grout in the anchor hole reaches the set strength, the anchor cable is tensioned and locked. The grout in the anchor hole includes the second cement grout in the bag and the cement soil formed by mixing the first cement grout and the third cement grout with the soil.
[0073] In this embodiment, the water-cement ratio of each cement slurry is the weight ratio of water to cement.
Claims
1. A rotary grouting anchor structure with a bladder-type enlarged head, characterized in that: and a second anchor plate assembly, the second anchor plate assembly comprising a plurality of anchor cables, the two anchor cable assemblies being arranged at intervals around a central axis, the two ends of each anchor cable being respectively formed with a pull-out end and a tensioning end, the pull-out end being located in the enlarged head cavity of the anchor cable hole, and the tensioning end extending outward from the anchor cable hole; the two anchor plate assemblies are arranged at intervals along the extension direction of the anchor cable hole, and the two anchor plate assemblies are both fixed on each anchor cable, wherein the second anchor plate assembly is located on the side of the first anchor plate assembly away from the tensioning end, and the pull-out end of each anchor cable is fixed on the two anchor plate assemblies; one end of the sac is open and formed with a slurry inlet, and the other end of the sac is closed, and the slurry inlet is sealed and fixed to the first anchor plate assembly; an anchor block formed by cement slurry is provided in the sac; A central hole is provided on the first anchor plate assembly, and the jet grouting drill rod can be passed through the central hole in a sealed manner and then pressed against the second anchor plate assembly to deliver the anchor rod assembly into the anchor rod hole; A grouting pipe hole and an exhaust pipe hole are provided on the first anchor plate assembly, wherein the grouting pipe hole is used for inserting the grouting pipe, and the exhaust pipe hole is used for inserting the exhaust pipe. When one end of the grouting pipe and the exhaust pipe are respectively inserted into the grouting pipe hole and the exhaust pipe hole, the other ends of the grouting pipe and the exhaust pipe extend outward from the anchor rod hole; when the grouting pipe is inserted into the grouting pipe hole, a first sealing ring is sleeved between the grouting pipe and the grouting pipe hole; when the exhaust pipe is inserted into the exhaust pipe hole, a second sealing ring is sleeved between the exhaust pipe and the exhaust pipe hole.
2. The rotary grouting anchor structure according to claim 1, characterized in that: One end of the bladder away from the tensioning end is sealingly fixed to the second anchor plate assembly, and the second anchor plate assembly closes the end of the bladder away from the tensioning end; or the end of the bladder away from the tensioning end is sealingly fixed to the second anchor plate assembly, and a guide cap is fixedly installed on the side of the second anchor plate assembly away from the tensioning end, and a slurry hole connecting the guide cap and the bladder is provided on the second anchor plate assembly, and the guide cap and the second anchor plate assembly jointly close the end of the bladder away from the tensioning end.
3. The rotary grouting anchor structure according to claim 1, characterized in that: An end of the bladder away from the tensioning end is a closed end, and the second anchor plate assembly is located in the bladder.
4. The rotary grouting anchor structure according to claim 1, characterized in that: Each anchor plate assembly includes an anchor plate and an extrusion plate. Corresponding to each anchor cable, an anchor hole in the shape of a through hole is provided on the anchor plate. The end of the anchor hole away from the tensioning end is formed into a conical hole with the small end facing the tensioning end. A clip group is arranged in the conical hole. The extrusion plate is located on the side of the anchor plate away from the tensioning end. The locking bolt connects the extrusion plate to the anchor plate, and the extrusion plate tightly squeezes the clips in the clip group into the conical hole to fix the anchor cable on the anchor plate.
5. The rotary grouting anchor structure according to claim 4, characterized in that: Corresponding to each anchor cable, an extrusion tube is provided between the anchor plate and the extrusion plate of the same anchor plate assembly. The extrusion tube is sleeved on the corresponding anchor cable, and the two ends of the extrusion tube are respectively pressed against the clamping piece and the extrusion plate.
6. The rotary grouting anchor structure according to claim 1, characterized in that: A cement soil enlarged head is provided on one side of the bladder bag facing the tensioning end. The diameter of the cement soil enlarged head is larger than the diameter of the free section, and the cement soil enlarged head is connected to the bladder bag.
7. The rotary grouting anchor structure according to claim 6, characterized in that: The outer diameter of the cement soil enlarged head is 0.8-1.2 times the outer diameter of the anchor block.