CN111455996A - Prefabricated prestressed anchor rod with guide device and construction method - Google Patents

Abstract

A prefabricated prestressed anchor rod with a guide device comprises a prefabricated prestressed anchor rod body and an anchor rod head guide device which are connected together; the anchor rod head guiding device is a cone. The cone is of a cone tip or frustum structure. The connecting device of the pre-stressed rod piece and the cone is characterized in that: the center of the cone is connected with the finish rolling threaded steel bars of the anchor rod through nuts, the center of the cone is welded with the metal piece of the anchor rod framework through the metal piece, the center of the cone is connected with the prestressed anchor rod and the steel bars in the cone through the nuts, the center of the cone is connected with the prestressed anchor rod and the prestressed anchor rod through flanges or steel bars in a welded mode, the prestressed anchor rod and the steel bars in the center of the cone are fixed to the flanges respectively and are connected with the two flanges through bolts, or the two flanges with the radius larger than that of the anchor rod, the peripheral bolts of the two flanges.

Description

Prefabricated prestressed anchor rod with guide device and construction method

Technical Field

The invention relates to a structure and a construction method of an anchor rod, in particular to a structure which does not utilize an existing hole, but presses the anchor rod into an extruded or rotating mode by using corresponding mechanical equipment and adopting a static pressure method, a vibration method, a tamping method, a spinning-in method and other methods to enable the anchor rod to automatically enter the ground layer, and comprises an anchor rod component and a construction method which form the invention.

Background

The applicant CN2020103929335 is a post-tensioning prestress applying device of a rock bolt, CN2020207414687 is a prestress rock bolt with a connecting structure, and CN 210562163U is a prefabricated prestress rock bolt rod piece; CN2020207248475 a prefabricated assembled anti-floating tensile prestressed anchorage member, CN2020207240914 a prestressed does not have anchor rod reinforcing bar, stock and construction method of bondning, CN2020207240755, a tubular column for prestressed anchorage, stock and construction method basic content: a prestressed anchor rod of a connecting structure at least comprises two prestressed anchor rods which are connected with each other through a connecting device. At least one of the two prestressed anchors is a prefabricated prestressed anchor for prestressed anchorage of the reinforcing steel bars by the concrete coagulation force. The connecting device is characterized in that connecting nuts are used for connecting reinforcing steel bars of two prestressed anchor rods, the reinforcing steel bars of the two prestressed anchor rods are welded and connected, the reinforcing steel bars of the two prestressed anchor rods are respectively fixed on flanges and are connected with the two flanges through bolts, the two flanges with the radius larger than that of the anchor rods are adopted, the peripheries of the two flanges are connected through bolts, or the two flanges are locked through anchor ear bolts. When the connecting nut is connected with the steel bars of the two prestressed anchor rods, the connecting nut is simultaneously the connecting device and the anchor locking nut, and the prestressed anchor rod steel bars are in threaded connection with the anchor locking nut at the moment and are finish-rolled deformed steel bars.

The disclosed CN2017103161244 is a variable-diameter steel reinforcement cage for an anchor rod or a pile foundation and an application thereof, the variable-diameter steel reinforcement cage for the anchor rod or the pile foundation is a main reinforcement of a variable-diameter steel reinforcement cage expansion head for the anchor rod or the pile foundation, and the variable-diameter steel reinforcement cage with various three-dimensional shape characteristics is formed according to the use requirement of specific engineering and a variable-diameter principle, and comprises a cylinder, a polygonal cylinder, a truncated cone, a trapezoidal cylinder, a sphere and a bamboo joint-shaped cylinder; according to the use performance requirement of specific engineering, the diameter-variable steel reinforcement cage of the pile foundation with the super-large diameter is characterized in that a double-layer cage middle sleeve cage is formed.

CN2017208194362 uses a variable-diameter steel reinforcement cage as a framework of an anchor rod or a pile foundation, and comprises a pre-tensioning or post-tensioning (prefabricated) combined assembly type prestressed anchor rod component, wherein the (prefabricated) prestressed connecting anchor rod has a large application range and value in basement anti-floating, foundation pit supporting and the like.

The prestressed anchor rod technology is required to be widely applied to underground engineering, and is more economic and environment-friendly compared with the common traditional process in the aspects of solving the problems of basement anti-floating, foundation pit supporting and the like; meanwhile, the method has great advantages in the aspects of cost, construction period, durability and the like. CN2017103638836, a method for overcoming deformation of an anti-floating fixed diameter anchor head or an enlarged head anchor rod system, is a prior application of the applicant, when a drill hole is drilled to a designed depth, high pressure jet grouting construction or mechanical reaming construction can be carried out, a pull rod of an anchor rod and a fixed diameter anchor head or an enlarged head are put down, after the enlarged head is in place, an enlarging mechanism enlarges the enlarged head to a designed size, and then high pressure grouting or pouring concrete forms a pile in the enlarged body section and the whole free section; the tie rod in the anchor rod adopts a twisted steel bar which can apply prestress; binding the spiral stirrups and the foundation slab steel bars on the substrate, and avoiding collision with prestressed steel bars in the binding process; and finally, the formwork is erected to pour the foundation concrete foundation slab. The prestressed anchor rod with the connecting structure (including the prefabricated prestressed anchor rod) is particularly convenient to use in engineering, and the preparation cost of the prestressed pre-stressed solidification type anchor rod can be low by considering the prefabricated prestressed anchor rod. The anchor rod is more meaningful in application. However, the enlarged head and the prestressed anchor rod still have improvements. There are many kinds of requirements when the stress anchor rod is connected with the enlarged head. The two ends of the existing finish-rolled threaded steel bar nut are in equal diameter, the applicant also provides a reducing connecting nut which can meet the application of a prestressed anchor rod of the existing connecting structure, and particularly has different steel bar main bars when the anchor rod is connected with an expansion head.

However, how the anchor rod enters the ground layer generally adopts a drilled hole or an existing hole to insert or pour the anchor rod, and the structural design and the construction method of the anchor rod which enters the ground layer from the ground layer still deserves to be provided.

Disclosure of Invention

The invention aims to provide an anchor rod capable of automatically entering a stratum under the action of external force and a construction method, in particular to an anchor rod capable of automatically entering the stratum and a construction method, wherein various prestressed anchor rods (including prefabricated prestressed anchor rods) are particularly convenient to use in engineering, the preparation cost of the prefabricated prestressed anchor rod also called a pre-tensioned prestressed solidification type anchor rod is low, the efficiency of the anchor rod capable of automatically entering the stratum and the construction method can be greatly improved, and the structure is simple.

The technical scheme of the invention is that the prefabricated prestressed anchor rod which enters the stratum and is provided with the guiding device comprises an anchor rod body and an anchor rod head which are connected together, wherein the anchor rod head is a cone; the cone is a cone tip or frustum structure; the cross section of the cone tip or the frustum is a circle or a polyhedron; the cone may also be made of concrete or polymer material.

The connection mode of the prefabricated prestressed rod piece and the cone comprises but is not limited to that the center of the cone is provided with a nut connected with the finish rolled threaded steel bar of the anchor rod, or the center of the cone is provided with a metal piece welded with the metal piece of the anchor rod framework; or the connecting device is a connecting nut which connects the prestressed anchor rod and the steel bar of the cone, or the prestressed anchor rod is connected through the flange or the steel bar welding, the prestressed anchor rod and the steel bar of the cone are respectively fixed on the flange and are connected with the two flanges through bolts, the two flanges with the radius larger than that of the anchor rod are adopted, the peripheral bolts of the two flanges are connected, or the two flanges are locked by anchor ear bolts (locking anchor structure), or the direct main steel bar welding is available without using the flanges.

The cone can also be made of concrete, reinforced concrete prefabricated parts, steel, castings or high polymers and other materials.

The anchor rod entering the stratum can be pressed into the stratum in a squeezing or rotating mode by adopting a static pressure method, a vibration method, a tamping method and a spinning method.

The side of the anchor rod body and the anchor rod head can be provided with uniform external threads which can screw in the rod body. The anchor rod can be an enlarged plate structure of a screw, namely a huge model, namely a self-advancing (self-tapping) anchor rod, and the anchor rod body provided with the external thread can be screwed into the ground layer through a screwing machine (torsion applying equipment), and the anchor rod is particularly a pre-tensioning pre-fabricated prestressed set anchor rod body. The construction method for self-feeding (self-tapping) anchor rod to enter stratum comprises the following steps: the self-advancing anchor rod capable of being directly and automatically drilled has two functions of a drill rod and an anchor rod, and a working procedure of withdrawing the drill rod and inserting the anchor rod is not needed.

The invention is applicable to the fields including but not limited to the functional application of anti-floating and tensile strength, and the specific application includes building, road, mining, tunnel and bridge, foundation pit and mountain slope protection, and geological disaster treatment; also used in the fields of pressure-resistant engineering and the like. The prefabricated prestressed anchor rod body can be used as a prefabricated prestressed compression-resistant pile according to the requirements of engineering design purposes.

The application method comprises the following steps: the anchor rod can be pressed into the ground by static pressure, vibration, tamping or spinning, or can be poured into the ground by hole-forming and pouring. And (3) after entering the stratum, installing the top of the anchor rod steel bar: the installation can be seen in the prior patent application of the applicant, and is fixed by embedding a flange nut (a kit) sleeved on a steel bar (a pull rod), or can be connected with a steel bar framework system of a foundation slab through an anchor plate and fixed by a nut, and the flange nut (the kit) is used for fixing the stress when the stress is applied by a post-tensioning method (post-stressing); grouting or pouring concrete into the gap between the steel bar and the hole to complete the prestressed anchor rod piece; and finally, installing a formwork and pouring a concrete foundation slab fixing anchor plate. And when the pre-fabricated prestressed anchor rod component is adopted, post-stressing is not needed. The pre-tensioning method does not require stress application and has been prepared as a pre-stressed unit.

Has the advantages that: the guide device cannot be prefabricated on the anchor rod because the stress of the prefabricated prestressed anchor rod is applied; however, after the structure of the invention is applied, various prestressed anchor rods (including the prefabricated prestressed anchor rod) are particularly convenient to use in engineering, and considering that the prefabricated prestressed anchor rod can also be called a pre-tensioned prestressed solidification type anchor rod, the preparation cost is low, the self-entering stratum anchor rod and the construction method can greatly improve the efficiency, and the structure is simple. The invention adopts static pressure method, vibration method, placing or tamping method, spinning method, etc. to press the anchor rod into the ground layer, especially the structure of the side surface of the anchor rod body provided with uniform external screw thread is added with the anchor rod head of the invention, the anchor rod can be an enlarged version structure of screw, and the anchor rod body provided with external screw thread can be easily screwed into the ground layer through a spinning machine. After entering the stratum, the top installation of the anchor rod reinforcing steel bars is carried out, and the method has a large application range and value in basement anti-floating, foundation pit supporting and the like.

The invention uses the pre-tensioned prestressed anchor rod to make the bearing capacity reach the applied prestress value required by design, and the deformation of the free section of the prestressed anchor rod can be continuously adjusted. The engineering quality and the construction safety are improved.

Drawings

Fig. 1 is a schematic structural view of an anchor rod body and an anchor head guide device of the present invention.

Fig. 2 is a schematic structural view of two anchor rod bodies and an anchor rod head guide device connected according to the present invention.

FIG. 3 is a schematic view of the center of the anchor rod head guide device with a nut hole.

Fig. 4 is a schematic view of the bolt head of the present invention having a nut hole in the center thereof and a flange in the nut hole.

Fig. 5 is a schematic structural view illustrating the connection of the anchor head guide of fig. 3 or 4 with finish rolled steel bars of the anchor.

Fig. 6 is a schematic view of a connection structure of the anchor rod head guide device with the steel reinforcement cage and the finish rolled steel bars of the anchor rod in fig. 5.

Fig. 7 is a schematic view of the anchor rod head guide device and the anchor rod connecting structure (bolt connection) of the invention.

Fig. 8 is a schematic view showing the structure (welded connection) of the head guide device of the anchor rod and the anchor rod connecting structure according to the present invention.

Fig. 9 is a schematic view showing the structure of the anchor rod head guide device and the anchor rod connecting structure (outer ring bolt connection) according to the present invention.

Fig. 10 is a schematic view showing the structure (anchor locking bolt) of the anchor rod head guide device and anchor rod connecting structure according to the present invention.

Fig. 11 is a schematic view of the structure of the anchor rod head guide device and the anchor rod connecting structure (the built-in flange and the nut are connected by steel bars).

Detailed Description

As shown, the parts in the figures are exemplified: the anchor rod capable of directly entering the stratum by means of pressure and the like comprises an anchor rod body and an anchor rod head which are connected together, wherein the anchor rod head is a cone; the cone is of a cone tip or frustum structure, the connecting structure is that the center of the cone is a cone, a nut is connected with the anchor rod finish rolling threaded steel bar, or the center of the cone is a metal piece welded with the metal piece of the anchor rod framework, and the cross section of the cone tip or the frustum is a circle or a polyhedron; the cone may also be made of concrete or polymer material.

The figure is as follows: 1-1 parts of embedded nuts, 2 parts of finish rolling steel bars, 3 parts of framework steel bars, 4 parts of anchor rod columns, 1-2 parts of internal structure screw nuts, 1-3 parts of external ring screw nuts, 1-4 parts of welding, 1-5 parts of anchor locking structures of anchor bolts and anchor bolts, and 1-6 parts of connection of internal flanges or nuts by steel bars.

The side of the anchor rod body can be provided with uniform external threads, and the spiral steel sheet can be poured on the outer wall of the anchor rod body in the concrete pouring process or the concrete pouring process to form the threaded anchor rod body 4.

In fig. 1-2, the structure of the present invention is schematically illustrated as an anchor rod 4 and an anchor rod head 1 connected to the anchor rod 4. In fig. 3-6, the center of the anchor rod head is provided with a structure schematic diagram of an embedded nut 1-1. The anchor rod head is provided with a nut hole in the center, and the nut hole is provided with a flange. Fig. 5 is a schematic structural view illustrating the connection of the head of the anchor rod of fig. 3 or 4 with the finish-rolled steel bars 2 of the anchor rod according to the present invention. Fig. 6 shows an anchor head with a steel skeleton 3; the anchor rod head and anchor rod connecting structures in the figures 7-10 are all connecting structures capable of bearing force, such as inner structure screw nuts 1-2, welding 1-4, outer ring screw nuts 1-3 and anchor structure hoop bolt lock 1-5.

Concrete embodiment of the anchor rod construction method into the ground:

the anchor rod entering the stratum can adopt a static pressure method and can simulate a static pressure method concrete pile ground entering process; the construction method includes, but is not limited to, static pressure, self-advancing (self-tapping) screwing-in, hammering driving-in method, vibration implantation method, vibration and high-pressure water cutting soil body implantation method, drilling hole, grooving implantation method and the like.

The static pressure pile construction process comprises the following steps:

according to the actual situation on site, the construction of the prefabricated anchor rod (especially the stress prefabricated anchor rod) adopts a hydrostatic pile pressing method construction process.

The construction procedure of the static pressure anchor rod is as follows: measuring and positioning, positioning an anchor rod machine, feeding an anchor rod to the front of the anchor rod machine, hanging the anchor rod, aligning an anchor rod body, sinking the anchor rod by static pressure, measuring the height (penetration degree), stopping pressing the anchor rod, testing the quality of the anchor rod, and cutting the locking concrete layer of the anchor rod head and the upper anchor rod.

The static pressure anchor rod construction process includes the steps of positioning, centering and straightening the anchor rod, pressing the anchor rod again, feeding the anchor rod and the like.

1. Paying-off positioning

And (4) setting an axis control point at a place which is not influenced by the operation of the anchor rod on the construction site, then measuring and placing the point location according to a design drawing, and identifying.

2. And (3) rechecking the anchor rod position: before the anchor rod machine is in place, a recorder needs to check whether the anchor rod position is correct according to the size of the figure, and if the deviation of the anchor rod position exceeds the specification requirement, the anchor rod position needs to be measured again.

3. The anchor rod machine takes place, centers and straightens: for walking full hydraulic pressure, the ship walks longitudinally and transversely through the action of the large ship walking oil cylinder and the small ship walking oil cylinder, so that the tip of the anchor rod is aligned with the position of the anchor rod, the anchor rod pressing oil pump is started to press the anchor rod into the soil for 2m, then the anchor rod is stopped to be pressed, and the verticality of the anchor rod in two vertical directions is corrected by using two theodolites.

4. And (3) pressing an anchor rod: the prefabricated anchor rod is clamped by utilizing the floating roof boosting principle of the clamp, and the anchor rod is pressed into the ground by using the pressure of the anchor rod pressing oil pump. The stroke of each anchor rod pressing is 2 m. And (3) loosening the clamp device after the first stroke is finished, lifting the clamp device by using the anchor rod pressing oil cylinder, clamping the anchor rod again after the clamp device is in place, and circulating the steps.

5. Cutting the anchor rod: if the anchor rod is pushed a distance above the ground and the anchor rod pressing force reaches a specified value (timely reporting the conditions with supervision, design and owners), the anchor rod is cut (the non-prestressed anchor rod can be cut) after design agreement according to the actual conditions on site.

6. When the anchor rod is pressed or sent, the original record of the number of the anchor rod, the type and the size of the anchor rod, the date of manufacturing the anchor rod, the ground surface elevation, the top elevation of the anchor rod and the verticality deviation is required to be made according to the relevant standards, and the record is real, accurate and complete.

The tamping method is similar to the above-mentioned method.

The construction method for the self-advancing (self-tapping) anchor rod to enter the stratum comprises the following steps: the large screw bolt type anchor rod can directly and automatically drill into the self-advancing anchor rod with two functions of a drill rod and an anchor rod without a process of withdrawing the drill rod and inserting the anchor rod. The self-advancing anchor rod has the function of integrating drilling, injection and anchoring, is an advanced anchoring system, solves the problem of hole collapse during the construction of a large pipe shed, and can ensure the anchoring effect under the complex geological conditions. The mortar anchor rod is obviously superior to the conventional mortar anchor rod with the same section in the aspects of bending resistance, shearing strength, surface bonding and the like, can be cut, connected, pre-stressed and released by load at will, has no special requirements on required machine tools and materials, is simple in process and has great application value.

The self-advancing anchor rod is a rod body full-thread rod piece and is provided with the anchor rod head (which can be hollow or solid), a connecting sleeve and the like.

The prefabricated prestressed rod body includes, but is not limited to, a prefabricated combined assembly type prestressed anchor rod piece, a prefabricated hollow or solid pipe column prestressed anchor rod piece, a single body or an elongated form thereof. The prefabricated prestressed rod body can be made of concrete, reinforced concrete, steel, castings, engineering plastics, graphene or high polymers and other materials.

The solid geometry of the pre-stressed rod body and the anchor rod head guide device comprises but is not limited to: cube, polyhedron, regular polyhedron, tetrahedron, cuboid, cylinder, round platform, prism, terrace with edges, circular cone, pyramid, bamboo joint, cluster, convex-concave, the shape of plane cross section includes but not limited to: square, rectangle, triangle, quadrilateral, rhombus, trapezoid, polygon, circle, ellipse, ring, sector and bow; the anchor rod member can be solid or hollow in section.

The bolt body has the following structure, also mentioned in the applicant's foregoing: the anchor rod body is especially a pre-stressed prefabricated anchor rod, or two pre-stressed prefabricated anchor rods are connected into a single anchor rod; the reinforcing steel bars of the two prestressed prefabricated anchor rods are connected by nuts or welded, the reinforcing steel bars of the two prestressed prefabricated anchor rods are respectively fixed on the flanges and connected with the two flanges by bolts, the two flanges with the radius larger than that of the anchor rods are adopted, the peripheries of the two flanges are connected by bolts, or the two flanges are locked by anchor ear bolts (a locking anchor structure).

At least one of the two prestressed prefabricated anchor rods is a prefabricated prestressed prefabricated anchor rod for anchoring the reinforcing steel bars in a prestressed manner by the concrete condensation force. When the connecting nut is connected with the steel bars of the two prestressed prefabricated anchor rods, the connecting nut is simultaneously the connecting device and the anchor locking nut, the connecting device and the anchor locking nut are connected with the prestressed prefabricated anchor rod steel bars in a threaded mode, and the prestressed prefabricated anchor rod steel bars are particularly finish-rolled deformed steel bars.

The prefabricated combined assembled anti-floating tensile anchor rod component can be divided into two main reinforcement structures of bonding and non-bonding reinforcing steel bars, a special concrete outer sleeve pipe or an independent outer sleeve pipe component and the like. The pre-fabricated prestressed anchor can pre-stress and anchor the steel bar by the coagulation force of concrete, etc., or can anchor the steel bar by an independent outer casing string component, or can be a post-tensioned prestressed anchor.

The prefabricated anchor rod can adopt an anti-floating tensile steel bar combined anchor rod pipe column (anchor rod body), comprises a concrete prefabricated pipe column provided with a steel bar framework, and is a pipe column for accommodating anchor rod steel bars, and the inner diameter of the pipe column is 3-7 cm, and the outer diameter of the pipe column is 14-30 cm, namely the diameter range of the prestressed anchor rod. The pipe column is provided with a rotary thread body.

A steel reinforcement framework is arranged in the concrete prefabricated pipe column; the concrete prefabricated pipe column can be movably connected or contacted with the pipe column at the lower end. The tubular column is the tubular column shape overcoat of stock reinforcing bar, passes the tubular column with the stock reinforcing bar, arranges the both ends of finished product tubular column in with the foraminiferous loading board that is greater than the tubular column internal diameter of central authorities, fixes the reinforcing bar end at the loading board or with reinforcing bar end welded fastening on the loading board with the nut when the stock that the loading board surface exposes is exerted stress, and the reinforcing bar is single finish rolling stock reinforcing bar, or several finish rolling stock reinforcing bar, and the loading board will have the prestressing force application device of porous and many reinforcing bars during several finish rolling stock reinforcing bar.

The lower end connecting structure of the anti-floating tensile anchor rod of the concrete prefabricated pipe column is grouting body or concrete of an expansion head. When the variable-diameter reinforcement cage is adopted, a concrete foundation with the diameter larger than that of a concrete prefabricated pipe column is poured, the variable-diameter reinforcement cage is wrapped, and the lower end nut of the anchor rod reinforcement is connected with or welded and fixed at the upper end of the main reinforcement of the variable-diameter reinforcement cage.

The non-adhesive anchor rod reinforcing steel bar is adopted, the surface of the non-adhesive anchor rod reinforcing steel bar is provided with an anti-corrosive grease layer, and a plastic film sleeve is arranged outside the anti-corrosive grease layer. The anchor rod reinforcing steel bars of the combined anchor rod are connected into a required length by adopting a nut connector or a welding mode. The steel bar nut connector can be embedded in the anchor rod in advance.

The anchor rod reinforcing steel bars in the anchor rod assembly are connected in parallel by one to 7.

The combined anchor rod is a pre-tensioned prestressed anti-floating tensile reinforcement anchor rod, the tubular column is a tubular column-shaped outer sleeve of the anchor rod reinforcement, the anchor rod reinforcement penetrates through the tubular column, the bearing plate with a hole in the center and larger than the inner diameter of the tubular column is arranged at the two ends of the finished tubular column, when the anchor rod exposed out of the surface of the bearing plate is stressed, the reinforcement end is fixed on the bearing plate or welded and fixed on the bearing plate by a nut, the reinforcement is a single finish rolling anchor rod reinforcement or a plurality of finish rolling anchor rod reinforcements, and the bearing plate is provided with a prestressed applying device with multiple holes and multiple reinforcements when the anchor rod reinforcements. The finished pipe column is prepared by pouring concrete or cement mortar, cement paste or other curable materials, and a steel reinforcement framework can be arranged inside the pipe column.

The main reinforcement of the variable-diameter steel reinforcement cage does not need prestress, so that a concrete foundation with the diameter larger than that of a concrete prefabricated pipe column is formed, and the foundation is grouted through a grouting pipe; has greater tensile and compressive capabilities. ) Therefore, the pipe column is an important element of the pipe column assembly type anti-floating tensile anchor assembly prefabricated by concrete. The lower end of the anchor rod steel bar fixes the upper end of the main bar; especially the mode such as spiro union or welding is fixed.

The extension continuous type anchor rod is a rod piece which can be continuously formed into an extension continuous type anchor rod and finally becomes an assembly. The anchor rod components are assembled to form an engineering part with compression resistance and tensile resistance (mainly tensile resistance and better effect) in practical application.

The main muscle reinforcing bar (including main muscle reinforcing bar or with main muscle reinforcing bar through coupling nut's main muscle reinforcing bar connection structure) is used as the structure of basic load to the main atress spare of stock, and the main muscle reinforcing bar can adopt ordinary reinforcing bar, include finish rolling reinforcing bar or add anticorrosive processing in surface again, and the anchor stock reinforcing bar of unbonded still can have following structure: the surface of the main reinforcement steel bar is provided with an anti-corrosive grease layer, and a plastic film sleeve is arranged outside the anti-corrosive grease layer; coating oil by an oiling device, coating the oil without binding ribs with a polyethylene or polypropylene plastic film by a plastic extruder, and molding a plastic sleeve (pipe) by a cooling cylinder mold; the plastic sleeve is wrapped by concrete or cement mortar, cement paste or other curable materials and is solidified; applying prestress on the main reinforcing steel bars after prestress (applying prestress after fixing is finished) to form a prestress anchor rod assembly; and locking the main reinforcing steel bars by nuts, and applying prestress to the tensioned reinforcing steel bars to form the prestressed anchor rod assembly.

When the plastic film sleeve reinforcing steel bar, especially the post-tensioned prestressing anti-floating tensile reinforcing steel bar anchor rod is applied, the prestressed main reinforcing steel bar actually forms a free section reinforcing steel bar, but does not extend any more, and has the function of applying stress.

The above description is only exemplary of the present invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A prefabricated prestressed anchor rod with a guide device is characterized by comprising a rod body of the prefabricated prestressed anchor rod and an anchor rod head guide device which are connected together; the anchor rod head guiding device is a cone.

2. A rock bolt according to claim 1, wherein the cone is of a conical point or frustum configuration.

3. A rock bolt according to claim 1, wherein the means for connecting the pre-stressed rod member to the cone is as follows: the center of the cone is connected with the finish rolling threaded steel bars of the anchor rod through nuts, the center of the cone is welded with the metal piece of the anchor rod framework through the metal piece, the center of the cone is connected with the prestressed anchor rod and the steel bars in the cone through the nuts, the center of the cone is connected with the prestressed anchor rod and the prestressed anchor rod through flanges or steel bars in a welded mode, the prestressed anchor rod and the steel bars in the center of the cone are fixed to the flanges respectively and are connected with the two flanges through bolts, or the two flanges with the radius larger than that of the anchor rod, the peripheral bolts of the two flanges.

4. A rock bolt according to claim 1 or 2, wherein the cross-section of the apex or frustum is circular or polyhedral.

5. A rock bolt according to claim 1 or 2, wherein the cone is made of concrete, reinforced concrete prefabricated parts, steel, castings or polymer materials.

6. A rock bolt according to claim 2 or 3, wherein the rock bolt shank and rock bolt head guide means, i.e. the side of the conical head of the guide rock bolt, is provided with uniform external screw threads allowing the shank to be screwed in.

7. A rock bolt according to claim 2 or 3, wherein the pre-fabricated prestressed rod body comprises a pre-fabricated assembled pre-stressed anchor rod member, a pre-fabricated hollow or solid tubular pre-stressed anchor rod member, a single pre-fabricated prestressed rod body or a connecting body of more than two pre-fabricated prestressed rods; the prefabricated prestressed rod body is made of concrete, reinforced concrete, steel, castings, engineering plastics, graphene or high polymer materials.

8. A rock bolt according to claim 2 or 3, wherein the solid geometry of the pre-stressed rod body and the rock bolt head guide means includes: cubes, polyhedrons, regular polyhedrons, tetrahedrons, cuboids, cylinders, round tables, prisms, prismatic tables, cones, pyramids, bamboo joints, strings and convexo-concave shapes; the shape of the planar cross-section includes: square, rectangle, triangle, quadrilateral, rhombus, trapezoid, polygon, circle, ellipse, ring, sector and bow; the anchor rod piece is of a solid or hollow structure.

9. A method of installing an anchor rod according to any one of claims 1 to 8 into a ground formation, wherein the anchor rod is driven into the ground formation at the intended location by static pressure, vibration, tamping or spinning.

10. The construction method of claim 6, wherein the anchor rod is a self-advancing anchor rod, the body of the anchor rod having external threads is screwed into the ground by a torque applying device, and the anchor rod is a pre-tensioned pre-stressed anchor rod assembly; the self-advancing anchor rod has two functions of a drill rod and an anchor rod.

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