Variable stiffness permeable anchor rod, reinforcement method and structure suitable for earth structure sites

Abstract

The present invention discloses a variable stiffness permeable anchor, reinforcement method, and structure suitable for raw earth structure ruins, comprising a permeable anchor section and a variable stiffness anchor section arranged in the soil of the ruins; the permeable anchor section is configured with a perforated bamboo tube inserted into the anchor, and the area between the perforated bamboo tube and the soil of the ruins is filled with water-absorbing material to form a water-absorbing section; the variable stiffness anchor section is configured with a bamboo tube with anchor blockers arranged at intervals, and the anchor reinforcement inserted into the bamboo tube is spaced apart with positioners to form a variable stiffness cavity; the tails of the anchor reinforcements in the two sections are connected to a steel wedge, and the fronts extend out of the soil of the ruins for fixation; the bamboo tubes are isolated from each other; and the anchor blockers are rotated along the bamboo tube by tension on the anchor reinforcement, thereby achieving variable stiffness. This structure has both permeable and variable stiffness functions, which can ensure that the anchor system still maintains a high pull-out bearing capacity when the interface slip is large, and can also ensure that the moisture content of the surrounding soil is at a low level through permeable drainage.

Description

Technical Field

[0001] The present invention belongs to the technical field of rammed earth building site reinforcement, and in particular relates to a variable stiffness permeable anchor rod suitable for raw earth structure sites, a reinforcement method and a structure. Background Art

[0002] Earthen building sites are one of the important cultural heritages in human history. There are a large number of earthen building sites in China, which are widely distributed and diverse in types. However, they generally suffer from defects such as cracks, erosion, weathering, and strength deterioration. If "rescue" reinforcement is not carried out in time, it is very easy to cause permanent loss of architectural relics and the historical and cultural information they carry.

[0003] Earthen building sites are generally large and magnificent, but due to defects such as cracks and erosion, their structural integrity is greatly weakened. Under external forces such as earthquakes, they are prone to overturning and collapse. Furthermore, rainfall can penetrate deep into the soil through these cracks, further reducing its strength and causing localized instability and collapse. Therefore, earthquakes and rainfall are the primary drivers of the stability of earthen building sites. The key to enhancing their stability lies in effectively strengthening and securing the site and controlling its moisture content.

[0004] In response to this problem, relevant scholars, based on the reinforcement principle of "safety first, minimal intervention, and no change to the original appearance", mainly use "anchoring" technology to covertly enhance its stability, that is, drilling holes on the surface of the site and implanting anchor rods, and injecting anchoring slurry into the holes to bond the anchor rods to the site body, thereby playing the role of binding the dangerous body and the stable body, and avoiding the instability and destruction of the site. However, the existing anchor rods of earthen sites mainly perform mechanical binding on the soil, while the control of the moisture content of the site is still mainly carried out by setting up protective sheds, covering with water-blocking materials, etc., which is costly and affects the public display of the site's cultural relics. The present invention aims to propose a new anchor rod structure, which can simultaneously achieve the functions of effectively binding the dangerous soil of the site and draining excess water from the soil of the site.

[0005] The advantages and disadvantages of the anchor structure currently used in the reinforcement of traditional earthen building sites are as follows:

[0006] For example, the fiberglass anchor rod and its manufacturing method proposed in publication number CN1644878A is a rod made of fiberglass reinforced plastic that is impregnated with resin and then heat-cured and molded in one step. The fiberglass yarn is arranged axially in the rod body, and the rod body is threaded. This achieves both anchoring and corrosion prevention effects. However, the rod body that provides the anchoring function will significantly reduce its anchoring capacity after slipping, and it is not water-permeable, which cannot solve the problem of high water content in the soil.

[0007] For example, Publication No. CN 114592509 A proposes a slope reinforcement anchor for construction projects. It features a shock-absorbing rod head and a threaded rod tail. While this achieves both anchoring and shock absorption, the anchoring capacity, which relies solely on the mechanical engagement between the rod tail threads and the soil, is significantly reduced after slippage and fails to address the problem of high water content in the soil.

[0008] For example, the bamboo anchor proposed in publication number CN 109235431 A mainly relies on the bonding force between the bamboo body, slurry and soil as the main source of anchoring capacity. However, the stress distribution of the full-length bonded anchor is extremely uneven, with the high stress area mainly concentrated near the hole mouth. The interfacial bonding strength at different anchoring depths cannot be fully exerted, resulting in a short effective anchoring length and low anchoring efficiency. In addition, the bamboo is extremely susceptible to corrosion in water-containing soil.

[0009] For example, the publication number CN 2793196 Y proposes a Nanzhu reinforced composite anchor rod, which is a composite of Nanzhu, adhesive and steel bars. However, the stress distribution of the full-length bonded anchor rod is extremely uneven, and the high stress area is mainly concentrated near the hole mouth. The interface bonding strength at different anchoring depths cannot be fully exerted, resulting in a short effective anchoring length and low anchoring efficiency.

[0010] For example, the drainage anchor bolt anchoring system proposed in publication number CN 109629566 A has a hollow anchor pipe with a threaded front end and is connected to a slurry outlet pipe in the middle and rear parts. A water-permeable hole and a wrapped filter are provided around the slurry outlet pipe. A rubber sleeve valve and a geobag are provided at the mouth of the slurry outlet pipe. A clamp clamps the geobag in the hollow anchor pipe. Grouting causes the geobag to expand in the soil, thereby generating a mechanical bite with the soil to further improve the anchoring capacity of the anchor bolt. A siphon device is then used to suck out the water passing through the water-permeable hole. However, the method of providing anchoring capacity is single, and the mechanical bite between the geobag and the soil will greatly reduce the anchoring capacity of the anchor bolt after the geobag slips. Summary of the Invention

[0011] To address the above-mentioned deficiencies in the prior art, the present invention aims to provide a variable-rigidity, permeable composite anchor suitable for reinforcing rammed earth buildings and sites, such as cave dwellings, rammed earth sites, ancient earthen tombs, and rammed earth city walls. This invention addresses the problems of existing metal anchors, such as poor durability and compatibility, low pull-out bearing capacity, stress concentration at the anchoring interface, and the tendency to cause insufficient anchoring force or localized premature damage to the site. By using a variable-rigidity structure and multi-layer permeable sections separated by water-insulating materials into two working spaces, a bamboo-reinforced composite anchor with both permeability and variable-rigidity functions is formed. This not only ensures that the anchoring system maintains a high pull-out bearing capacity even when the interface slip is large, but also ensures that the moisture content of the surrounding soil remains at a low level through permeable drainage.

[0012] The present invention is achieved through the following technical solutions.

[0013] In one aspect, the present invention provides a variable stiffness permeable anchor rod suitable for use in earthen structure sites. The variable stiffness permeable anchor rod comprises an anchor rod permeable section and an anchor rod variable stiffness section arranged in the soil of the site.

[0014] In the permeable section of the anchor rod, a perforated bamboo pipe is placed inside the ruins soil, and the anchor rod reinforcement is inserted into the bamboo pipe to form a non-bonded cavity; the space between the perforated bamboo pipe and the ruins soil is filled with water-absorbing material to form a water-absorbing section;

[0015] In the anchor rod variable stiffness section, bamboo pipes are arranged in the ruins soil, anchoring barriers are arranged at intervals on the bamboo pipes, the anchor rod reinforcement is inserted into the bamboo pipes, and positioners are arranged at intervals on the anchor rod reinforcement to form a variable stiffness cavity;

[0016] The tail of the anchor rod reinforcement in the permeable section and the anchor rod variable stiffness section is connected to the steel wedge, and the front part is extended to the site soil for fixation; the bamboo pipes in the permeable section and the anchor rod variable stiffness section are separated by flexible waterproof materials and waterproof layers;

[0017] The anchor rod reinforcement is pulled to push the anchor barrier to rotate along the bamboo pipe, thereby achieving variable stiffness of the anchor rod.

[0018] In the embodiment of the present invention, a water-permeable hole is opened on the outer wall of the bamboo pipe in the water-permeable section of the anchor rod, a water-absorbing pipe is sheathed on the outside of the anchor rod reinforcement, the bamboo pipe is sheathed on the water-absorbing pipe, and a water-permeable membrane is pasted between the bamboo pipe and the water-absorbing pipe.

[0019] In the embodiment of the present invention, a water suction pipe is arranged in the unbonded cavity of the bamboo tube inserted into the anchor bar body, and the water suction pipe is led out from the bottom of the permeable section to the outer facade of the ruins soil.

[0020] In an embodiment of the present invention, holes are opened at intervals on the bamboo pipe in the variable stiffness section of the anchor rod to accommodate glass fiber reinforced plastic grooves, and the anchoring blocker is rotatably connected along the glass fiber reinforced plastic grooves to achieve variable stiffness flipping.

[0021] In an embodiment of the present invention, the anchoring barrier includes a short wing plate, a long wing plate, a web plate and a rotatable steel ball; the rotatable steel ball is respectively connected to the short wing plate, the long wing plate and the web plate, the short wing plate and the long wing plate are distributed at an angle, and the tail of the long wing plate is closed to the bamboo pipe by a slurry-blocking membrane; the web plate extends radially along the bamboo pipe toward the anchor rod body and forms a certain angle with the bamboo pipe.

[0022] In an embodiment of the present invention, the locators arranged at intervals on the anchor rod reinforcement body of the anchor rod variable stiffness section include a steel bar protrusion and a support ring. The steel bar protrusion has a wedge-shaped surface, and the angle of inclination of the web along the bamboo pipe corresponds to the wedge-shaped surface of the steel bar protrusion.

[0023] In the embodiment of the present invention, a groove is formed at the tail end of the bamboo pipe and is fixed by a rubber ring.

[0024] In the embodiment of the present invention, modified mud is filled into the ruins soil outside the bamboo pipe.

[0025] Another aspect of the present invention provides a variable stiffness permeable anchor reinforcement method applicable to earthen structure ruins using the device, comprising:

[0026] The support ring and the reinforcement protrusion are connected at intervals in the rear half of the anchor bar body made of glass fiber rod or CFRP rod;

[0027] A fiberglass groove is provided on the rear half of the bamboo pipe; a water-permeable hole is provided on the front half of the bamboo pipe;

[0028] Anchoring barriers are installed in the fiberglass grooves of bamboo pipes in the anchor rod variable stiffness section and sealed with a slurry barrier film;

[0029] The anchor rod reinforcement is centrally inserted into the bamboo tube with the bamboo joints opened, and is inserted into the anchor rod water-permeable section 22 and the anchor rod variable stiffness section; the anchor rod reinforcement is pulled to push the anchor blocker to rotate along the bamboo tube, thereby achieving variable stiffness of the anchor rod reinforcement and reinforcing the ruins soil;

[0030] A flexible waterproof material and a waterproof layer are filled on the bamboo pipe between the anchor rod water permeable section and the anchor rod variable stiffness section; the slotted end of the bamboo pipe is fixed with a rubber ring; and a wedge-shaped expansion body is fixed at the end of the anchor rod reinforcement body;

[0031] The bamboo pipes in the permeable section of the anchor rod are filled with water-absorbing materials, and the bamboo pipes in the variable stiffness section of the anchor rod are filled with modified mud;

[0032] The rubber conduit is inserted into the bamboo pipe of the permeable section of the anchor rod, and the grooved pad and anchor plate are fixed at the end of the permeable section of the anchor rod. The rubber conduit is led out from the hole of the grooved pad to drain the water in the soil of the ruins.

[0033] In another aspect of the present invention, the anchor rods are applied to a reinforcement structure of an earthen structure site, wherein the variable stiffness permeable anchor rods are arranged in a plum blossom pattern on the facade of the site, and the variable stiffness permeable anchor rods are installed inside the site and inserted obliquely downward at an angle to the horizontal plane; adjacent rows of variable stiffness permeable anchor rods are staggered by 1 / 3 to 1 / 2 of the spacing;

[0034] When variable stiffness permeable anchor rods are applied to the facade of raw earth ruins, a siphon device is set on the outside;

[0035] If the variable stiffness permeable anchor rod is installed on the top of the cave, the two working sections of the variable stiffness permeable anchor rod will be lengthened respectively and inserted obliquely into the top of the cave. The drainage will be guided by the dead weight without the need to add a siphon device.

[0036] The present invention adopts the above technical solution, which has the following beneficial effects:

[0037] (1) The bamboo tube’s open-pore structure and multi-layered water-absorbing superimposed structure are used to solve the stability problem of the soil around the anchor caused by rainfall infiltration. Water-absorbing materials are filled between the bamboo tube and the anchor hole to absorb water from the soil around the anchor rod. The bamboo tube is equipped with a semi-permeable membrane. The water inside the bamboo tube and the surrounding water-absorbing materials will form a gradient difference, thereby guiding water into the bamboo tube. The water inside the tube is then removed through an external siphon device and a water-absorbing pipe, thereby reducing the moisture content of the surrounding soil and improving the anchoring capacity of the anchoring system. It can be used to enhance the stability and seismic resistance of earthen ruins structures, while controlling the water content in the soil to avoid structural instability and damage.

[0038] (2) Solve the problem of serious anchoring force loss of traditional uniform cross-section anchor rods when the slippage is large. A variable stiffness mechanism is proposed, which is combined with a multi-stage wedge-shaped anchor body to continuously provide a high anchoring force for the anchor rod / slurry interface under large slippage conditions; the variable stiffness structure of the present invention is mechanically engaged. As the steel bar (glass fiber) is pulled, the protrusion on it pushes the rotatable steel sheet on the bamboo pipe. One end of the steel sheet squeezes the bamboo pipe and the other end forms a certain angle with the pipe and is inserted into the soil to provide greater mechanical engagement, thereby improving the pull-out resistance of the anchor rod. The wedge-shaped expansion body at the end of the anchor rod squeezes the bamboo with the slotted end as the steel bar is pulled, further squeezing the surrounding soil to improve the local interface bonding strength of the anchor rod, thereby improving the performance of the anchor rod system.

[0039] (3) The permeable drainage function and the variable stiffness anchoring function are integrated into a single anchor rod, solving the problem of the single function of traditional anchor rods. The present invention has two independent working areas separated by a waterproof material, combining the permeable and variable stiffness functions to work together. While maintaining the pull-out bearing capacity after the anchor rod slips, the moisture in the soil around the anchor is guided into the bamboo tube and finally discharged, so that the moisture content in the soil of the ruins can be controlled.

[0040] (4) By rationally combining and arranging the new permeable variable-rigidity anchor rods, the problem that traditional anchor rods are difficult to effectively control the moisture content of the soil around the anchor rods can be solved; in areas with high soil moisture content, the permeable section of the anchor rod can be lengthened, and the anchor rod arrangement can be made denser to increase the drainage capacity; in areas with low soil moisture content, the permeable section can be shortened, and the variable-rigidity section and the tail wedge-shaped expansion body can be lengthened. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 It is a structural schematic diagram of the anchor rod in the present invention;

[0043] Figure 2 (a) and (b) are schematic diagrams of the pad at the end of the anchor rod in the present invention;

[0044] Figure 3 2 is a schematic cross-sectional view of the drainage section of the anchor rod in the present invention;

[0045] Figure 4 It is a structural cross-sectional view of the anchor rod in the present invention;

[0046] Figure 5 (a) and (b) are schematic diagrams of the variable stiffness structure in the anchor rod and the bamboo pipe connection component;

[0047] Figure 6 It is the layout drawing of anchor rods applied to the slope facade and the placement drawing of siphon device;

[0048] Figure 7 This is a schematic diagram of the various arrangements of anchor rods in the slope.

[0049] In the figure: 1. Anchor reinforcement (fiberglass rod or CFRP rod), 2. Nanzhu pipe, 3. Short wing plate, 4. Long wing plate, 5. Web plate, 6. Fiberglass groove, 7. Rotatable steel ball, 8. Steel bar protrusion, 9. Support ring, 10. Water-permeable hole, 11. Water-permeable membrane, 12. Slurry-blocking membrane, 13. Water-absorbing pipe, 14. Wedge-shaped expansion body, 15. Water-proof layer, 16. Water-proof material, 17. Grooved pad, 18. Anchor plate, 19. End slot; 20. Water-absorbing material, 21. Modified mud, 22. Anchor permeable section; 23. Anchor variable stiffness section; 24. Rubber ring, 25. Rubber catheter, 26. Site soil. DETAILED DESCRIPTION

[0050] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0051] like Figure 1 As shown, an embodiment of the present invention provides a variable stiffness permeable anchor suitable for earth structure sites, which mainly includes two parts: an anchor rod permeable section 22 and an anchor rod variable stiffness section 23; the anchor rod permeable section is used to realize the permeability function of the anchor rod; the anchor rod variable stiffness section is used to improve the pull-out resistance of the anchor rod and increase the mechanical bite force between the anchor rod itself and the surrounding soil.

[0052] like Figure 1 Combine Figure 3As shown, the anchor rod permeable section 22 includes an anchor rod reinforcement 1, bamboo pipe 2, a water absorption pipe 13 (made of bamboo charcoal, etc.), and a water-permeable membrane 11, located within the ruins soil 26. Within this section, the anchor rod reinforcement 1 and the bamboo pipe 2 form an unbonded cavity. The bamboo pipe has a water-permeable hole 10 on its outer wall, and a water-permeable membrane 11 is adhered to the inner side of the bamboo pipe. The anchor rod reinforcement 1 is a fiberglass rod or CFRP rod located in the middle of the ruins soil 26. The anchor rod reinforcement 1 is sheathed with a water absorption pipe 13, which is sheathed with bamboo pipe 2. The water-permeable membrane 11 is attached between the bamboo pipe 2 and the water absorption pipe 13. The water-permeable membrane 11 is a semi-permeable membrane used to divert water from the soil into the pipe without flowing out. Common semi-permeable membranes such as cellulose acetate membranes can be used. The semi-permeable membrane is adhered to the inner wall of the bamboo pipe with epoxy resin glue. Epoxy resin glue is an epoxy resin adhesive used in the construction industry. It should have excellent bonding strength and weather resistance, a tensile strength of not less than 65MPa, and should not suffer brittle failure. Its normal service life should not be less than the benchmark repair period of the site.

[0053] The anchor rod permeable section 22 is a water-absorbing section, and the space between the perforated bamboo pipe 2 and the ruins soil 26 is filled with water-absorbing material 20 to isolate it from the ruins soil 26 layer.

[0054] The anchor reinforcement body 1 is used to connect the wedge-shaped expansion body 14 and the anchor plate 18, and the bamboo pipe 2 is used to isolate the anchor reinforcement body from the ruins soil 26. A water suction pipe 25 is arranged between the bamboo pipe 2 and the anchor reinforcement body 1. The bamboo pipe 2 is provided with a water permeable hole 10, so that water can flow from the outside through the water permeable hole into the area between the anchor reinforcement body 1 and the bamboo pipe 2, and the water is led out through the water suction pipe 25 extending from the bottom of the permeable section to the outer facade of the ruins soil.

[0055] Among them, the diameter of the bamboo pipe is 10cm-15cm, and the diameter of the water hole is 0.5cm-1cm.

[0056] A grooved pad 17 is provided on the outside of the ruins soil 26 of the anchor rod permeable section 22. The grooved pad 17 has a disc-shaped structure, as shown in Figures 2(a) and (b). There is a reserved groove on the pad 17 used at the end of the anchor rod. The reserved groove is opened from the center of the pad to the edge of the pad. An anchor plate 18 is provided outside the grooved pad 17.

[0057] The length of the anchor rib 1 should be greater than the length of the bamboo pipe 2, and the excess part is mainly located at the front of the anchor rib. The anchor plate 18 is installed at the hole of the anchor rib, and the fiberglass rod or CFRP rod is passed through the anchor plate and fastened with bolts; the excess length of the anchor rib 1 is the sum of the thickness of the grooved pad 17 and the reserved length required for installing the anchor plate 18, bolts, and the tail extending out of the bamboo pipe.

[0058] The plane shape of the anchor plate 18 can be circular or square, and its diameter or side length should be 3-6 times the diameter of the drilled hole. After installation, the anchor plate and the nut are covered to ensure that their appearance is consistent with the original wall.

[0059] A flexible waterproof material 16 is provided on the anchor bar adjacent to the variable stiffness section 23, and a waterproof layer 15 is coated on the outer side of the waterproof material 16. The waterproof layer 15 and waterproof material 16 separate the variable stiffness working area in the rear half of the anchor bar from the permeable area in the front half, so that they do not affect each other's operation.

[0060] The variable stiffness section 23 of the anchor rod includes an anchor rod reinforcement body 1, a bamboo pipe 2 and an anchor barrier located in the ruins soil 26. The anchor rod reinforcement body 1 is located in the middle of the ruins soil 26 and is an integrated structure with the permeable section anchor rod. The bamboo pipe 2 is sleeved on the outside of the anchor rod reinforcement body 1. Correspondingly arranged steel bar protrusions 8 and support rings 9 are spaced apart on the anchor rod reinforcement body 1. Glass fiber reinforced plastic grooves 6 are spaced apart on the bamboo pipe 2, and anchor barriers with rotatable steel balls 7 are embedded. Several spaced-apart anchor barriers are fixed on the bamboo pipe 2 corresponding to the steel bar protrusions 8 and support rings 9.

[0061] Therefore, according to the force transmission mode and working principle of the anchor rod, its entire length can be divided into two working areas: 1) The inner wall of the front half of the bamboo pipe is attached with a water-permeable membrane 11, and there are pre-set water-permeable holes 10 on the bamboo pipe, adopting a multi-layer structure, which is a water-permeable space; 2) The back half of the bamboo pipe is embedded with a rotatable variable stiffness structure, and the anchor rod reinforcement (steel bar or glass fiber) is welded with steel bar protrusions 8 and support rings 9, which interact with each other to play a variable stiffness function, forming a variable stiffness space.

[0062] like Figure 1 and Figure 3 As shown, all the internal bamboo nodes of the bamboo pipe 2 except the last one are opened to allow the anchor bar 1 to be inserted; the anchor bar 1 should be inserted into the bamboo pipe 2 until the last bamboo node. The length of the fiberglass rod or CFRP rod 1 not wrapped by the bamboo pipe 2 should be the same as the thickness of the ruins wall, and 5-15cm should be left to connect and fix it with the pad 17 and bolt 18. A circular hole the size of the anchor bar 1 is left in the last bamboo node of the bamboo pipe 2, and the anchor bar 1 is connected to the steel wedge 14 after it is extended. A certain length is left after the last bamboo node at the tail of the bamboo pipe 2, and a groove 19 is cut at the end of the tail of the bamboo pipe 2 along the length direction, and it is tightened by a rubber ring 24.

[0063] The bamboo pipe is used as an anchor sleeve to separate the soil of the site from the internal structure of the bamboo pipe. Holes are opened along the wall of the bamboo pipe for the placement of anchor barriers. The diameter of the hole is 1 / 2 of the diameter of the selected fiberglass rod or CFRP rod.

[0064] The bamboo pipe 2 should be made of natural bamboo that is straight and has no obvious damage. All bamboo nodes 11 inside the bamboo except the last node are drilled or split and hollowed out. After the bamboo nodes are opened by splitting, they should be restored to their original circular cross-section by pasting and wrapping carbon fiber cloth or tying with steel wire.

[0065] like Figure 4 As shown, the variable stiffness function of the anchor rod of the present invention is mainly provided by the anchor blocker, steel bar protrusion 8 and support ring 9 in the variable stiffness working range. As shown in Figures 5(a) and (b), the anchor blocker includes a short wing plate 3, a long wing plate 4, a web 5 and a rotatable steel ball 7; the short wing plate 3 and the long wing plate 4 are distributed at an angle, and a rotatable steel ball 7 is fixed on the inner side of the connecting end of the short wing plate 3 and the long wing plate 4. The rotatable steel ball 7 is connected to the web 5. The web 5 extends radially toward the anchor rod reinforcement 1 along the bamboo tube 2 and forms a certain angle with the bamboo tube. The end of the long wing plate 4 is separated from the bamboo tube 2 by a slurry barrier 12. The long and short wing plates and the web 5 are welded together on the rotatable steel ball 7 to form an anchor blocker. There are four groups of anchor blocks in the variable stiffness range, and each group of anchor blocks is reserved at a certain distance from the steel bar protrusion 8. The number of anchor blocks increases from the end to the tail of the anchor rod.

[0066] The steel bar protrusion 8 is wedge-shaped, and the angle of the web 5 along the bamboo tube 2 corresponds to the wedge surface of the steel bar protrusion 8. The end of the long wing plate 4 and the bamboo tube 2 are sealed with a slurry barrier 12, and the support ring 9 is located within the closed circle of the slurry barrier 12 and is distributed in a cross shape along the anchor bar body 1.

[0067] The short wing plate 3 is welded to the web 5 and forms an angle of 5°-10° with the bamboo tube 2. The short wing plate 3 is used to increase the mechanical bite force between the anchor bar and the ruins soil. The long wing plate 4 is welded to the web 5 and forms an angle of 15°-25° with the bamboo tube 2. The long wing plate 4 is used to squeeze the bamboo tube wall to provide greater variable stiffness. Among them: a small amount of rubber is pasted on the inside of the long web 4, and its end is connected to the bamboo tube with a slurry barrier 12 to prevent grouting material from entering and affecting the bite between the two. The steel bar protrusion 8 and the support ring 9 are connected to the anchor bar 1. The end of the anchor bar should be reserved with half the length of the bamboo section to form an end slot 19. The last section is not completely opened, and only a circular hole the size of the anchor bar 1 is opened in the bamboo section to facilitate the extension of the anchor bar 1 to the steel bar wedge 14 for connection. The ends of the long wing plates 4 and the bamboo pipe 2 are sealed with a grouting membrane 12 to prevent grouting material from entering the angle and affecting the squeeze between the wing plates and the bamboo pipe. The rotatable steel ball 7 is used to fix the web 5 and provide rotational capability. Its diameter is the same as the opening diameter.

[0068] The steel bar protrusion is used to push the web of the anchor blocker when the fiberglass rod or CFRP rod is under tension. As the steel bar protrusion pushes, the anchor blocker starts to rotate, thereby increasing the pull-out resistance. The steel bar protrusion is connected to the fiberglass rod or CFRP rod. In this embodiment, the distance between the steel bar protrusion and the web of the anchor blocker is 3mm-5mm.

[0069] The support ring is used to protect the bamboo tubing from damage caused by the anchor block. The support ring is slightly smaller in diameter than the bamboo tubing; in this embodiment, the preferred width is 3-5 cm. It is welded to the rebar using four steel bars. The support ring is located behind the protrusion of the rebar, corresponding to the long wing of the anchor block.

[0070] A wedge-shaped expansion body 14 is connected to the anchor plate body at the end of the bamboo pipe 2 in the variable-stiffness section of the anchor rod. Located at the end of the fiberglass or CFRP rod, the wedge-shaped expansion body connects to the fiberglass or CFRP rod extending out of the bamboo pipe. This wedge-shaped expansion body, along with the bamboo pipe slotted along its length and the rubber ring around the end of the bamboo pipe, creates a squeezing effect on the surrounding soil, further improving anchoring performance.

[0071] After drilling holes outside the anchor bolt's variable stiffness section, fill it with modified slurry 21. This forms a load-bearing zone with the anchor plate's variable stiffness section. The modified slurry can be mixed with scattered soil from the site, cement, fly ash, and glutinous rice paste with 5% silica sol. The mass ratio of these components is 60:20:10:10, resulting in a water-cement ratio of 0.31. This can also be adjusted based on the strength of the site's rammed earth.

[0072] In one embodiment, the anchor bar body made of fiberglass rod or CFRP rod has a diameter of 2cm-4cm and a length of 600cm-1600cm. The tail of the anchor bar body should extend 4cm-6cm beyond the bamboo tube for connecting to the wedge-shaped expansion body.

[0073] The embodiment of the present invention further provides a method for reinforcing a variable stiffness permeable anchor rod applicable to a raw earth structure site, comprising the following steps:

[0074] S1, connecting the support ring 9 and the steel bar protrusion 8 at intervals on the anchor bar body 1 in the rear half of the anchor bar with variable stiffness section 23 made of glass fiber rod or CFRP rod;

[0075] All bamboo joints are opened inside the bamboo pipe 2, and a glass fiber reinforced plastic groove 6 is separated on the back half of the bamboo pipe 2; and a water-permeable hole 10 is separated on the front half of the bamboo pipe 2;

[0076] S2: An anchor blocker is installed in the fiberglass groove 6 of the bamboo pipe 2 in the anchor rod variable stiffness section 23, forming a blocking structure through the steel bar protrusion 8 pre-connected to the anchor rod reinforcement 1; and the blocker is sealed with a slurry barrier 12; a bamboo section at the very end of the bamboo pipe is not completely opened, with only a circular hole the size of the anchor rod reinforcement to allow the anchor rod reinforcement to extend out and then weld a wedge-shaped expansion body 14; the very end half of the bamboo pipe is grooved along the length and tightened with a rubber ring 24, and the tail end is deep into the bamboo pipe and welded to the wedge-shaped expansion body 14;

[0077] S3, insert the anchor bar 1 into the bamboo tube 2 with the bamboo joints opened, insert the anchor bar water-permeable section 22 and the anchor bar variable stiffness section 23; the anchor bar is pulled and pushes the anchor blocker to rotate along the bamboo tube, achieving variable stiffness of the anchor bar and reinforcing the ruins soil;

[0078] S4. Cover the bamboo tube 2 between the permeable section 22 and the variable stiffness section 23 with a waterproof material 16 and a waterproof layer 15. Secure the bamboo tube 2 with a rubber ring 24 by inserting a slot 19 at the tail end. Reserve a connection position for the stainless steel wedge-shaped expansion body 14 at the end of the anchor bar 1 in the variable stiffness section 23. Secure the wedge-shaped expansion body 14 at the end of the anchor bar 1.

[0079] S5, pouring water-absorbing material 20 into the outside of the bamboo pipe 2 in the anchor rod water-permeable section 22, and pouring modified mud 21 into the bamboo pipe 2 in the anchor rod variable stiffness section 23;

[0080] S6, the rubber tube 25 is inserted into the bamboo pipe 2 of the anchor rod water-permeable section 22, the grooved pad 17 and the anchor plate 18 are fixed at the end of the anchor rod water-permeable section 22, and the rubber tube 25 is led out from the hole of the grooved pad 17 to discharge the water in the ruins soil.

[0081] The present invention also provides a solution for applying variable stiffness permeable anchor rods to the exterior facade of the slope. Figure 6 As shown in the figure, the spacing between variable stiffness permeable anchors should be 8 to 16 times of their diameter to ensure that the disturbance and compaction of the soil can cover the adjacent variable stiffness permeable anchors, increase the soil pressure around the adjacent variable stiffness permeable anchors and the bond strength of the tensile interface, thereby improving the bearing capacity of the variable stiffness permeable anchors.

[0082] Variable-rigidity permeable anchor rods should be arranged in a plum blossom pattern on the exterior facade of the site. They can be evenly distributed along the wall surface or gradually denser as the wall height increases. Anchor rods are not required within the 1 / 4H range at the bottom of the wall. Adjacent rows of variable-rigidity permeable anchor rods should be staggered by 1 / 3 to 1 / 2 of the distance between each other. The vertical spacing between rows should be 10 times the diameter of the bearing plate, D, or 10D. The horizontal spacing between adjacent vertical columns of anchor rods should be 5 times the diameter of the bearing plate, D, or 5D. Depending on the existing morphology of the site, these anchor rods can be evenly distributed along the exterior facade of the wall or gradually denser as the wall height increases.

[0083] The present invention can also be applied to raw earth ruins or cave tops. Figure 7 As shown in the figure, when installing on the slope facade, the problem that traditional anchor rods are difficult to effectively control the moisture content of the soil around the anchor can be solved by rationally combining and arranging the new permeable variable stiffness anchor rods. The permeable section can be appropriately extended in the upper part with higher moisture content to increase drainage efficiency, and the anchor rod arrangement can be more dense. The permeable section in the area with lower moisture content in the lower part of the slope can be shortened, and the variable stiffness section and the tail wedge-shaped expansion can be made along the length.

[0084] When the variable stiffness permeable anchor rod of the present invention is applied to the exterior facade of a raw earth site, a siphon device can be set up on the outside. Three variable stiffness permeable anchor rods can be used with a set of siphon devices. A rubber conduit is inserted into the interior of the variable stiffness permeable anchor rod through the groove of the anchor plate, and the water inside the anchor rod is sucked out by the working principle of the siphon device.

[0085] If the variable stiffness permeable anchor rod is installed on the top of the cave, the two working sections of the variable stiffness permeable anchor rod can be lengthened respectively, with the end facing downward and the tail facing upward, and inserted obliquely into the top of the cave. The specific number and size of the required variable stiffness permeable anchor rod can be determined according to the conditions of the cave. When the variable stiffness permeable anchor rod is applied to the top of the cave, there is no need to add a siphon device. The front anchor plate of the variable stiffness permeable anchor rod has a prefabricated groove, which can allow water to flow out through gravity.

[0086] In addition, when installing variable stiffness permeable anchor rods in the ruins, they should be inserted obliquely downward at an angle of 10 to 30 degrees to the horizontal plane.

[0087] There are two ways to drain water with variable stiffness permeable anchor rods: (1) When used outside the site, the tail of the variable stiffness permeable anchor rod is downward, the end is upward, and the angle is obliquely upward. A siphon device is used for drainage. The siphon device is connected to a conduit deep inside the variable stiffness permeable anchor rod; (2) When used inside the site (such as the top of a cave), the variable stiffness permeable anchor rod should be installed at an angle of 10 to 30 degrees to the horizontal plane and inserted obliquely downward. The water flows out by its own weight. The port pad is pre-made with a notch to facilitate water outflow, and then a drainage pipe is installed to drain the water.

[0088] The present invention has the following advantages:

[0089] 1) Anchor rod drainage space. The anchor hole is filled with absorbent material to absorb moisture in the soil around the anchor rod. There are absorbent pipes and semi-permeable membranes inside the anchor rod. The moisture inside and outside the anchor rod will form a gradient difference, thereby attracting external water to flow into the absorbent material filled in the anchor hole, and then flow into the anchor rod through the permeable holes on the bamboo pipe and temporarily stored in the drainage space. Then, a siphon device is connected to the outside of the plastic pipe to continuously suck out the temporarily stored water, thereby increasing the density of the soil, increasing the adhesion of the soil, and improving the anchoring performance of the anchor rod during work. The several variable stiffness structures in the variable stiffness space can provide different degrees of pull-out resistance, which greatly improves the pull-out resistance of the anchor rod.

[0090] 2) The variable stiffness structure inside the bamboo tube in the anchor rod consists of long and short wing plates, a web, a steel bar protrusion, and a support ring. The steel bar protrusion pushes the web to drive the long wing plate to rotate, squeezing the bamboo tube from the outside. The internal support ring provides support force. The interaction between the inside and outside makes it more solid and will not be damaged by easy pulling. The long wing plate changes from the axial position of the anchor rod to form a certain angle with the anchor rod, which greatly improves the mechanical bite ability with the soil when the anchor rod is pulled outward, thereby increasing the anchoring capacity.

[0091] 3) The glass fiber rod or CFRP rod extending from the tail of the anchor rod is bonded with multiple wedge-shaped expansion bodies, which interact with the grooved bamboo pipe at the tail. As the wedge-shaped expansion body squeezes the grooved bamboo pipe, the two interact to squeeze the surrounding soil, compacting the surrounding soil and improving the anchoring performance.

[0092] 4) The stress transfer between the glass fiber rods or CFRP rods and the rammed earth body is transitioned through the bamboo pipes, which can gradually transfer the stress of the glass fiber rods or CFRP rods to the rammed earth body through the bamboo and anchoring agent, avoiding the difficulty in coordinating the deformation caused by the large strength difference between the materials, so that the stress can be evenly dissipated in the soil of the ruins, thereby ensuring the safety of the ruins itself.

[0093] 5) The anchor rod can be divided into two areas after drilling. Grouting is carried out along the section where the stiffness of the anchor rod changes. The length of the grouting section is consistent with the section where the stiffness of the anchor rod changes, and the two form a load-bearing area. The front half of the anchor hole is filled with a large amount of water-absorbing material. The length of this section is consistent with the length of the permeable section of the front half of the anchor rod, forming a permeable area.

[0094] In summary, compared with natural bamboo and wood anchor rods and metal anchor rods, the anchor rod of the present invention has significant stress-bearing performance advantages in the reinforcement and protection of earthen ruins.

[0095] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features therein according to the disclosed technical content without creative labor, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. A variable stiffness permeable anchor suitable for earth structure sites, characterized in that: The variable stiffness permeable anchor includes a permeable anchor section and a variable stiffness anchor section arranged in the soil of the site; In the permeable section of the anchor rod, perforated bamboo pipes are placed inside the soil of the site, and the anchor rod reinforcement is inserted into the bamboo pipes to form a non-bonded cavity; Fill the area between the bamboo pipe with holes and the ruins soil with water-absorbing materials to form a water-absorbing section; The moisture inside and outside the bamboo and the surrounding water-absorbing materials guides water into the bamboo pipe, and then the moisture inside the bamboo pipe is discharged; In the anchor rod variable stiffness section, bamboo pipes are arranged in the ruins soil, anchoring barriers are arranged at intervals on the bamboo pipes, the anchor rod reinforcement is inserted into the bamboo pipes, and positioners are arranged at intervals on the anchor rod reinforcement to form a variable stiffness cavity; Holes are opened on the bamboo pipe in the variable stiffness section of the anchor rod to place glass fiber reinforced plastic grooves. The anchor blocker is connected by rotating along the glass fiber reinforced plastic groove to achieve variable stiffness flipping. The locators arranged at intervals on the anchor bar body in the variable stiffness section of the anchor bar include a steel bar protrusion and a support ring. The steel bar protrusion has a wedge-shaped surface, and the angle at which the web is inclined along the bamboo tube corresponds to the wedge-shaped surface of the steel bar protrusion. The anchor rod reinforcement is made of fiberglass rod or CFRP rod. The steel bar protrusion is used to push the web of the anchor blocker when the fiberglass rod or CFRP rod is under tension. The support ring is used to ensure that the bamboo pipe will not be damaged by the squeezing of the anchor blocker. The anchor barrier includes a short wing plate, a long wing plate, a web plate, and a rotatable steel ball; the rotatable steel ball connects the short wing plate, the long wing plate, and the web plate respectively. The short wing plate and the long wing plate are distributed at an angle, and the tail of the long wing plate is sealed with the bamboo pipe by a slurry barrier membrane; the web plate extends radially along the bamboo pipe toward the anchor bar and forms a certain angle with the bamboo pipe; The tail of the anchor rod reinforcement in the permeable section and the anchor rod variable stiffness section is connected to the steel wedge, and the front part is extended to the site soil for fixation; the bamboo pipes in the permeable section and the anchor rod variable stiffness section are separated by flexible waterproof materials and waterproof layers; The anchor rod reinforcement is pulled to push the anchor barrier to rotate along the bamboo pipe, thereby achieving variable stiffness of the anchor rod.

2. The variable stiffness permeable anchor suitable for earth structure ruins according to claim 1, characterized in that: A permeable hole is provided on the wall of the bamboo pipe in the permeable section of the anchor rod, a water-absorbing pipe is sheathed outside the anchor rod reinforcement body, the bamboo pipe is sheathed outside the water-absorbing pipe, and a permeable membrane is pasted between the bamboo pipe and the water-absorbing pipe.

3. The variable stiffness permeable anchor suitable for earth structure ruins according to claim 2, characterized in that: A water suction pipe is arranged in the unbonded cavity of the bamboo tube inserted into the anchor bar body, and the water suction pipe is led out from the bottom of the permeable section to the outer facade of the ruins.

4. The variable stiffness permeable anchor suitable for earth structure ruins according to claim 1, characterized in that: The end of the bamboo pipe is grooved and fixed with a rubber ring.

5. The variable stiffness permeable anchor rod suitable for earth structure ruins according to claim 1, characterized in that: Fill the modified mud into the soil of the ruins outside the bamboo pipe.

6. A method for reinforcing a variable stiffness permeable anchor rod suitable for a raw earth structure site using the anchor rod according to any one of claims 1 to 5, characterized in that: include: The support ring and the reinforcement protrusion are connected at intervals in the rear half of the anchor bar body made of glass fiber rod or CFRP rod; A fiberglass groove is provided on the rear half of the bamboo pipe; a water-permeable hole is provided on the front half of the bamboo pipe; Anchoring barriers are installed in the fiberglass grooves of bamboo pipes in the anchor rod variable stiffness section and sealed with a slurry barrier film; The anchor rod reinforcement is centrally inserted into the bamboo tube with the bamboo joints opened, and then inserted into the anchor rod's permeable section and the anchor rod's variable stiffness section. The anchor rod reinforcement is pulled, pushing the anchor blocker to rotate along the bamboo tube, achieving anchor rod variable stiffness and reinforcing the site soil. A flexible waterproof material and a waterproof layer are filled on the bamboo pipe between the anchor rod water permeable section and the anchor rod variable stiffness section; the slotted end of the bamboo pipe is fixed with a rubber ring; and a wedge-shaped expansion body is fixed at the end of the anchor rod reinforcement body; The bamboo pipes in the permeable section of the anchor rod are filled with water-absorbing materials, and the bamboo pipes in the variable stiffness section of the anchor rod are filled with modified mud; The rubber conduit is inserted into the bamboo pipe of the permeable section of the anchor rod, and the grooved pad and anchor plate are fixed at the end of the permeable section of the anchor rod. The rubber conduit is led out from the hole of the grooved pad to drain the water in the soil of the ruins.

7. An anchor rod according to any one of claims 1 to 5 is used for reinforcing a raw earth structure site, characterized in that: Variable stiffness permeable anchor rods are arranged in a plum blossom pattern on the exterior of the site. Variable stiffness permeable anchor rods are installed inside the site and inserted obliquely downward at an angle to the horizontal plane. Adjacent rows of variable stiffness permeable anchor rods are staggered by 1 / 3 to 1 / 2 of the spacing. When variable stiffness permeable anchor rods are applied to the facade of raw earth ruins, a siphon device is set on the outside; If the variable stiffness permeable anchor rod is installed on the top of the cave, the two working sections of the variable stiffness permeable anchor rod will be lengthened respectively and inserted obliquely into the top of the cave. The drainage will be guided by the dead weight without the need to add a siphon device.

Images