CN113585249B - Three-layer structure expanded end anchor rod system and construction method - Google Patents

Three-layer structure expanded end anchor rod system and construction method Download PDF

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CN113585249B
CN113585249B CN202110870390.8A CN202110870390A CN113585249B CN 113585249 B CN113585249 B CN 113585249B CN 202110870390 A CN202110870390 A CN 202110870390A CN 113585249 B CN113585249 B CN 113585249B
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anchor rod
anchor
geopolymer
expanded
layer
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CN113585249A (en
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曹海莹
张军钊
李雪倩
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Yanshan University
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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74—Means for anchoring structural elements or bulkheads
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/006—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing mineral polymers, e.g. geopolymers of the Davidovits type
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74—Means for anchoring structural elements or bulkheads
    • E02D5/80—Ground anchors
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/74—Means for anchoring structural elements or bulkheads
    • E02D5/80—Ground anchors
    • E02D5/808—Ground anchors anchored by using exclusively a bonding material
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2300/00—Materials
    • E02D2300/0004—Synthetics
    • E02D2300/0018—Cement used as binder
    • E02D2300/002—Concrete
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2300/00—Materials
    • E02D2300/0045—Composites
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2600/00—Miscellaneous
    • E02D2600/30—Miscellaneous comprising anchoring details
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding

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  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
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  • General Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
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  • General Engineering & Computer Science (AREA)
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Abstract

The invention discloses an anchor rod system with an expanded end of a three-layer structure and a construction method, wherein the anchor rod system comprises an anchor rod body, an anchorage device, an anchor disc, a geopolymer column core manufactured based on solid waste of geopolymer, an expanded concrete wrapping layer and a solidified bonding interface layer; the anchor rod expanding end part is provided with a geopolymer column core, an expanded concrete wrapping layer and a curing bonding interface layer from the anchor rod body to the outside in sequence, so that the anchor rod expanding end with a three-layer structure is formed. The application method comprises the steps of prefabricating and assembling of the geopolymer column core, hole forming of the anchor hole, slurry preparation, spraying of the curing agent, hole entering of the geopolymer column core, slip casting and stretching and fixing of the anchor rod. According to the invention, the anchor rod is designed by the self composition, the material of the expansion end of the anchor rod system and the structural form of the expansion end, so that the bearing capacity and the anti-pulling force of the anchor rod are improved, the construction cost is reduced, and the anchor rod is more energy-saving and environment-friendly in utilization. The invention has simple structure principle, simple pouring process, easy operation and high feasibility.

Description

Three-layer structure expanded end anchor rod system and construction method
Technical Field
The invention belongs to the technical field of building construction, relates to an anchor rod structure, and particularly relates to a three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers and a construction method.
Background
In order to ensure the safety and reliability of construction, the anchor rod anchoring technology is widely applied to the engineering construction fields of foundation pit engineering, railway engineering, hydraulic and hydroelectric engineering, slope engineering, basement engineering, anti-floating engineering, tunnel engineering, mine roadway engineering and the like. However, the existing anchor rod supporting structure generally has the problems of low mechanical efficiency, poor resistance to pulling of the anchor rod, overhigh construction cost, underground space pollution caused by the fact that the used anchor rod body is abandoned in the soil and the like. In order to obviously improve the bearing capacity of the anchor rod, load dispersion type anchor rods, hole expansion type anchor rods and other types of anchor rods are provided, the load transmission mechanism of the anchor rods can be improved, the soil body strength can be fully adjusted, and the bearing capacity of the anchor rods can be greatly improved. The hole-expanding anchor rod can raise bearing capacity obviously in the range of anchoring body with limited length, its expanding head end can produce supporting resistance, and its side surface can produce frictional resistance with soil body, so that it belongs to friction-supporting composite anchor rod.
Based on the three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers and the construction method, the anchor rod bearing capacity and the uplift resistance are improved, the construction cost is reduced, and the anchor rod is more energy-saving and environment-friendly in utilization.
Disclosure of Invention
One of the purposes of the invention is to provide a three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers, so that the bearing capacity and the pulling resistance of the anchor rod are improved, the construction cost is reduced, and the anchor rod utilization is more energy-saving and environment-friendly.
In order to achieve the purpose, the invention provides the following scheme:
the invention provides a three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers, which mainly comprises:
the bottom end of the anchor rod body is used for inserting a soil body;
the geopolymer column core is arranged at the bottom end of the anchor rod body and is made of industrial solid waste;
the expanded concrete wrapping layer forms an expanded end and is tightly attached to and wraps the outer part of the geopolymer column core;
the solidified bonding interface layer is matched with the shape of the expansion end and is fixedly bonded between the outer surface of the expanded concrete wrapping layer and the soil body; the geopolymer column core, the expanded concrete wrapping layer and the solidified bonding interface layer form an anchoring expansion end of an anchor rod system;
the anchor device comprises an anchor device and an anchor disc, wherein the anchor disc is used for being arranged at the bottom end of the anchor rod body, and the anchor device is used for tensioning and locking the top end of the anchor rod body.
Optionally, the anchoring expansion end may be a spherical expansion end, a truncated cone expansion end, or the like. For example, when the anchoring expanded end is a spherical expanded end, the corresponding expanded concrete wrapping layer and the corresponding curing bonding interface layer are both spherical shells.
Optionally, the anchor comprises a nut fixedly connected to the top of the anchor rod body and an anchor plate fixed externally. And the anchorage device is arranged at the top of the anchor rod body and can be tensioned and locked.
Optionally, the anchor rod further comprises an outer sleeve, the outer sleeve is sleeved outside the anchor rod body, and the outer sleeve is located above the anchoring expansion end.
Optionally, the outer sleeve is made of PVC, and may be referred to as "PVC pipe" for short, and the outer sleeve is sleeved outside the anchor rod body, and has an inner diameter of 40 to 60mm.
Optionally, the geopolymer column core is of a cylindrical structure with the diameter of 100-250mm and the height of 200-500cm; it is possible to assemble the geopolymer with the bolt body in advance at the factory.
Optionally, the contact surface between the geopolymer column core and the expansive concrete wrapping layer, that is, the outer surface of the geopolymer column core is provided with one or more combinations of protrusions, depressions (or called as "grooves"), honeycomb surfaces, spurs or barbs, so as to enhance the adhesion and friction between the geopolymer column core and the expansive concrete wrapping layer.
Optionally, the protrusions may be one or a combination of hemispherical protrusions, square protrusions or pyramidal protrusions; the depressions (or referred to as "grooves") may be one or a combination of hemispherical depressions, square depressions, or pyramidal depressions. The bulges can be annular continuous bulges or discontinuous bulges; similarly, the recess (or referred to as "groove") may also be an annular continuous recess or an intermittent recess.
Optionally, the raw materials of the expanded concrete coating layer comprise sulphoaluminate type expanded cement, an expanding agent, a retarder and a water reducing agent. The sulphoaluminate type expansion cement can adopt the sulphoaluminate type expansion cement commonly used in the market, including K type, M type and S type expansion cement, alunite, sulphoaluminate type expansion cement and the like; proper amount of expanding agent, retarder and water reducing agent. After the expanded concrete wrapping layer is poured and formed, the volume expansion shape can be in a bulb shape, extrusion prestress is generated between the expanded concrete wrapping layer and a soil body, and the frictional resistance between the expanded concrete wrapping layer and the soil body is enhanced, so that the pulling resistance of the anchor rod is improved.
Optionally, the outer diameter of the expanded concrete wrapping layer before pouring is 400 to 600mm, and the height of the expanded concrete wrapping layer is 200 to 500cm.
Optionally, the solidified bonding interface layer is formed by spraying a soil solidifying agent between the expanded concrete wrapping layer and the soil body.
Optionally, the cured bonding interface layer is a concrete-concrete cured bonding interface layer, and is formed by the expanded concrete wrapping layer and the soil body together under the action of a soil curing agent sprayed in the construction process, and the cured bonding interface layer can be shaped like a bulb. The curing agent is selected according to soil properties, and if the inorganic soil curing agent can be adopted, the curing agent is suitable for almost all types of soil; organic soil curing agent or ionic soil curing agent is selected under the condition of cohesive soil, or different types of soil curing agents are used in a matching way, and the like. The existence of the soil-concrete curing bonding interface layer improves the mechanical strength of the soil body around the anchor rod, and increases the bonding force or the frictional resistance between the soil body and the surface of the expanded concrete wrapping layer, thereby realizing the improvement of the anchoring force.
Optionally, the anchor disc is a metal disc with a thickness of 6 mm-15 mm and a diameter of 15 cm-30 cm.
Meanwhile, another purpose of the present invention is to provide a construction method of an enlarged end anchor rod system based on the above three-layer structure, which mainly comprises:
prefabricating a geopolymer column core, and assembling the prefabricated geopolymer column core and the bottom end of the anchor rod body together;
performing anchor hole forming construction, and constructing at the bottom end of the anchor hole to form an expanded aperture section;
inserting the anchor rod body assembled with the geopolymer column core into the anchor hole, and spraying a soil curing agent on the enlarged hole diameter section;
injecting the prepared concrete slurry mixed expanding agent into the expanded pore diameter section, and forming an anchoring expanded end of the anchor rod body after the concrete slurry expands and solidifies;
and tensioning and locking according to the design and fixing the anchor on the top end of the anchor rod body.
Optionally, drilling with a high pressure jet drilling machine to form the anchor hole.
Optionally, the geopolymer column core takes industrial solid waste steel slag and mineral powder as raw materials and is prepared by mixing the raw materialsThe alkali activator and the additive are prepared under the combined action; the steel slag is medium-high alkalinity converter steel slag, the mineral powder is S95-grade granulated blast furnace mineral powder, and the specific surface area of the steel slag and the mineral powder is 450m 2 The alkali activator adopts feldspar and sodium carbonate in a mass ratio of Na 2 O：SiO 2 1.2 to 1.5, wherein the additive comprises alkali-resistant glass fiber, graphene oxide and sodium sulfate;
wherein the mass fraction of the steel slag is 30-60%, the mass fraction of the mineral powder is 40-70%, the mass fraction of the alkali-activator is 3-7% of the mass sum of the steel slag and the mineral powder, the water-gel ratio is 0.25-0.45, the mass fraction of the alkali-resistant glass fiber is 0.1-0.3% of the mass sum of the steel slag and the mineral powder, the mass fraction of the graphene oxide is 0.01-0.03% of the mass sum of the steel slag and the mineral powder, and the mass fraction of the sodium sulfate is 1-1.5% of the mass sum of the steel slag and the mineral powder; the alkali-resistant glass fiber inhibits the expansion of the steel slag and the gaps among the graphene oxide filling particles, so that the whole structure is compact while the volume is unchanged, the strength of a geopolymer is ensured, and the holding force of the geopolymer to a reinforcing steel bar, namely an anchor rod body, is improved.
The working principle of the invention is as follows:
1. after the anchor rod is stressed, the anchor rod body diffuses force to the soil body step by step through a three-layer structure, wherein the three-layer structure comprises a geopolymer column core, an expanded concrete wrapping layer and a solidified bonding interface layer;
2. the anchoring and expanding end of the anchor rod system increases the contact area between the anchoring section and the soil layer so as to increase the frictional resistance between the anchoring section and the soil layer, and the local expanding of the anchoring and expanding end of the anchor rod system changes the generation mode of anchoring force, namely the bearing force of the front end surface of the expanding end is generated so as to greatly improve the anchoring force of the anchor rod system;
3. the expansive concrete wrapping layer in the anchoring and expanding end exerts pre-pressure on the soil body after pouring and forming, so that the frictional resistance between the anchoring and expanding end of the three-layer structure and the soil body is enhanced, and the pulling resistance of the anchor rod is improved;
4. before grouting, spraying a soil curing agent on the inner surface of the expanded end section of the anchor hole, combining the expanded concrete wrapping layer and a surrounding soil layer into a spherical shell-shaped soil-concrete curing bonding interface layer after grouting forming, improving the mechanical strength of the surrounding soil body, and increasing the bonding force and the frictional resistance of the surface of the soil body and the expanded concrete wrapping layer, thereby achieving the purpose of improving the anchoring force;
5. the solid waste is used for preparing the geopolymer to replace concrete, so that the anchor rod is more energy-saving and environment-friendly in utilization.
Compared with the prior art, the invention has the following technical effects:
the invention provides a three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers, which is characterized in that comprehensive design is carried out on the anchor rod, materials of an anchoring body and the structural form of the anchor rod, and a three-layer composite anchor rod structure consisting of a geopolymer column core, an expanded concrete wrapping layer and a solidified bonding interface layer is adopted, so that the bearing capacity of the anchor rod and the surrounding soil body is fully exerted, and the bearing capacity and the uplift resistance of the anchor rod system are improved; the solid waste is used for preparing the geopolymer to replace concrete, so that the material is more energy-saving and environment-friendly, and the engineering cost is reduced. The enlarged-end anchor rod system is simple in structural principle, the construction method is easy to operate, high in feasibility and more economical, and materials are easy to obtain. The anchor rod bearing capacity and the uplift resistance can be effectively improved, the engineering cost is reduced, and the anchor rod is more energy-saving and environment-friendly in utilization.
The three-layer structure expanded end anchor rod system based on the solid waste utilization of the geopolymer and the construction method can be widely popularized in the fields of anchor rods and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers, disclosed by an embodiment of the invention;
FIG. 2 is a schematic structural diagram of an enlarged end of a three-layer structure according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view of an enlarged end of a three-layer structure according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an anchor rod body and an anchor disc according to an embodiment of the present invention;
FIG. 5 is a schematic view of an assembly of a geopolymer core and an anchor rod body according to an embodiment of the present invention;
FIG. 6-1 is a schematic illustration of a first outer surface configuration of a geopolymer core disclosed in an embodiment of the present invention;
FIG. 6-2 is a schematic illustration of a second outer surface configuration of a geopolymer core disclosed in an embodiment of the present invention;
FIGS. 6-3 are schematic illustrations of a third outer surface configuration of a geopolymer core disclosed in an embodiment of the present invention;
fig. 7 is a construction flow chart of the anchor rod system disclosed in the embodiment of the present invention.
Wherein the reference numerals are: 1. an anchor rod body; 2. an anchorage device; 3. an outer sleeve; 4. a geopolymer column core; 5. an expanded concrete wrapping layer; 6. expanding the diameter of the end pore-forming hole; 7. an anchor disc; 8. solidifying the bonding interface layer; 9. and (4) soil body.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
One of the purposes of the invention is to provide a three-layer structure expanded end anchor rod system based on solid waste utilization of geopolymers, so as to improve the bearing capacity and the pulling resistance of the anchor rod, reduce the construction cost and enable the anchor rod to be utilized more in an energy-saving and environment-friendly manner.
It is yet another object of the present invention to provide a construction method for an enlarged end bolt system.
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description thereof.
Example one
As shown in fig. 1 to 6, the present embodiment provides an expanded end anchor system based on solid waste utilization of geopolymer, and the expanded end anchor system has a three-layer structure, so that it may be referred to as a "three-layer structure expanded end anchor system". The three-layer structure expanded end anchor rod system comprises an anchor rod body 1, an anchor device 2, an outer sleeve 3, a geopolymer column core 4, an expanded concrete wrapping layer 5, an anchor disc 7 and a curing bonding interface layer 8. The geopolymer column core 4 directly wraps the bottom of the anchor rod body 1, the outer part of the geopolymer column core is connected with the expanded concrete wrapping layer 5, the outermost layer is a solidified bonding interface layer 8 formed by the expanded concrete wrapping layer 5 and a soil body 9 under the combined action of soil curing agents sprayed in the construction process, and the solidified bonding interface layer 8 is a soil-concrete solidified bonding interface layer. This embodiment is through the material and the structural style to stock itself constitution, stock system expansion end carry out the integrated design, has formed the anchor expansion end that possesses geopolymer post core 4, expanded concrete parcel layer 5 and the 8 three layer construction of solidification bonding interface layer to improve stock bearing capacity and withdrawal resistance with this, reduce engineering cost, let the stock utilize energy-concerving and environment-protective more. The anchor rod system of this embodiment structure principle is simple, and it is simple to pour the flow, easily operation, and the feasibility is high.
In this embodiment, as shown in fig. 5, the anchor rod body 1 should be ensured to be coaxial with the central axis of the geopolymer column core 4, the geopolymer column core 4 may be poured in a factory in advance, the raw materials are taken according to a certain ratio, and the geopolymer column core 4 with the standard strength is obtained after the processes of stirring, water adding and stirring, vibrating, mold filling, maintaining and the like, and the geopolymer column core 4 and the anchor rod body 1 are assembled together and then transported to a construction site for later use.
In this embodiment, as shown in fig. 4, the anchor disk 7 is preferably a metal disk having a thickness of 6mm to 15mm and a diameter of 15cm to 30 cm; the preferable selection of the anchor rod body 1 is screw-thread steel, and the preferable selection of the diameter of the reinforcing steel bar is 30 to 60mm.
In the embodiment, the diameter of the geopolymer column core 4 is preferably 100 to 250mm, and the length (or called height) is preferably 200 to 500cm; the prefabricated geopolymer core 4 can be assembled with the bolt body 1 in advance at the factory. The column core takes industrial solid waste steel slag and mineral powder as raw materials, and prepares a geopolymer meeting the strength requirement under the combined action of an alkali activator and an additive. The steel slag is preferably medium-high alkalinity converter steel slag, the mineral powder is preferably S95-grade granulated blast furnace mineral powder, and the specific surface areas of the steel slag and the mineral powder can reach 450m 2 About/kg. The alkali activator is preferably feldspar and soda ash according to the mass ratio Na 2 O：SiO 2 The alkali activator for vitreous body is prepared from 1.2 to 1.5, wherein the additive comprises alkali-resistant glass fiber, graphene oxide and sodium sulfate. The steel slag-mineral powder composite material comprises, by mass, 30-60% of steel slag, 40-70% of mineral powder, 3-7% of alkali activator, 0.25-0.45 of water-gel ratio, 0.1-0.3% of alkali-resistant glass fiber, 0.01-0.03% of graphene oxide and 1-1.5% of sodium sulfate. The alkali activator provides an alkaline condition for the reaction of the steel slag and the mineral powder, the steel slag and the mineral powder activated by sodium sulfate are easier to react, and the alkali-resistant glass fiber inhibits the expansion of the steel slag and the graphene oxide fills gaps among particles, so that the whole structure volume is unchanged and is tighter, the strength of the geopolymer is ensured, and the bond force of the geopolymer to the reinforcing steel bar are improved.
In this embodiment, the outer surface of the geopolymer column core 4 is set to different shapes in the casting process, such as convex (hemispherical, square or pyramidal), concave (hemispherical, square or pyramidal), honeycomb surface, spurs, barbs, etc., so as to enhance the bonding friction force between the geopolymer column core and the expanded concrete wrapping layer 5. As a preferable mode, in this embodiment, it is preferable that the outer surface of the geopolymer column core 4 is provided with a continuous annular protrusion structure, that is, a plurality of protrusions are uniformly distributed on the outer surface of the geopolymer column core 4; as one case, as shown in fig. 6-1, the cross section of the annular protrusion is hemispherical. Alternatively, as shown in fig. 6-2, the cross-section of the annular protrusion may be square. In yet another case, as shown in fig. 6-3, the cross-section of the annular protrusion may be pyramidal.
In this embodiment, before the expanded concrete wrapping layer 5 is poured, it is preferable that: a cylinder with an outer diameter of 400 to 600mm and a height (or length) of 200 to 500cm. The raw materials of the expanded concrete coating layer 5 comprise sulphoaluminate type expanded cement, an expanding agent, a retarder and a water reducing agent. The sulphoaluminate type expansion cement can adopt the sulphoaluminate type expansion cement commonly used in the market, including K type, M type and S type expansion cement, alunite, sulphoaluminate type expansion cement and the like; proper amount of expanding agent, retarder and water reducing agent. After the expanded concrete wrapping layer 5 is cast and formed, the volume expansion shape can be like a spherical shell (or a bulb), and the volume expansion shape generates extrusion prestress with the soil body 9, so that the frictional resistance between the volume expansion shape and the soil body 9 is enhanced, and the pulling resistance of the anchor rod is improved.
In this embodiment, the solidified bonding interface layer 8 is formed by the expanded concrete cladding layer 5 and the soil 9 under the action of the soil solidifying agent sprayed in the construction process, and is matched with the shape of the expanded concrete cladding layer 5, for example, the volume expansion shape of the expanded concrete cladding layer 5 after casting can be a spherical shell shape (or a bulb shape), and the solidified bonding interface layer 8 can also be a spherical shell shape (or a bulb shape). The soil stabilizer is selected according to soil properties, such as an inorganic soil stabilizer, and is suitable for almost all types of soil; organic soil curing agent or ionic soil curing agent is selected under the condition of cohesive soil, or different types of soil curing agents are used in a matching way, and the like. The existence of the soil-concrete curing bonding interface layer improves the mechanical strength of the soil body around the anchor rod, and increases the bonding force or the frictional resistance between the soil body and the surface of the expanded concrete coating layer, thereby realizing the improvement of the anchoring force.
In this embodiment, the anchor device 2 and the anchor disk 7 are conventional components in an anchor rod system, and for the prior art, the specific structure and the working principle thereof are not described herein again.
The invention also provides a construction method based on the three-layer structure expanded-end anchor rod system, as shown in fig. 7, the construction method mainly comprises the following steps:
s1, prefabricating 4 layers of geopolymer column cores: after stirring, water adding and stirring, vibration die filling, maintenance and the like, the geopolymer column core 4 with the strength up to the standard is obtained and assembled with the bottom of the anchor rod body 1, and then the assembly is transported to a construction site for later use.
S2, positioning anchor holes and forming holes: and (2) drilling by using a high-pressure jet grouting drilling machine, mounting a drill bit at the front end part of a drill rod of the high-pressure jet grouting drilling machine, and setting the drilling direction and the drilling position of the drill rod according to the specified anchor rod body 1 position and the anchor rod body 1 pore-forming direction. And (4) after the bottom of the anchor rod body 1 is drilled to the designed depth, withdrawing the drill bit and the drilling machine from the hole.
The drill bit on the drill rod of the high-pressure rotary spraying drilling machine is replaced by a high-pressure rotary spraying nozzle, the high-pressure rotary spraying nozzle is placed at the designed position of the expanded end, the drill rod is gradually pushed, the high-pressure rotary spraying nozzle rotates to spray water flow, and the soil body 9 on the peripheral side is cut in the pushing process. Carrying out reaming operation by controlling the injection pressure of the high-pressure rotary spray nozzle or the advancing speed of the drill rod, and stopping injection cutting after reaching the position of the expanded end pore-forming diameter 6 to form an expanded aperture; the particular location of the enlarged end bore diameter 6 is shown in fig. 1 and 3.
S3, preparing a grouting body: preparing cement grout from the raw materials of the expansive concrete by using an on-site concrete preparing instrument to form mixed grout.
S4, inserting a geopolymer column core 4 and an anchor rod body 1 into a hole: and when the high-pressure rotary spraying nozzle drill rod ascends gradually, the high-pressure rotary spraying nozzle is used for rotatably spraying the soil curing agent to spray the expanded end part, the spraying is stopped after the whole spherical expanded hole section is sprayed, and the drill rod of the high-pressure rotary spraying drilling machine and the high-pressure rotary spraying nozzle are withdrawn from the anchor hole. And (4) inserting the geopolymer column core anchor rod 4 prepared in the step (S1) into the anchor hole, and ensuring that the anchor rod body 1 is coaxial with the anchor hole.
S5, grouting and forming: and (3) placing a high-pressure rotary spraying nozzle of the high-pressure rotary spraying drilling machine at the bottom of the anchor hole, injecting the cement mixed slurry prepared in the step (3) and the expanding agent into the anchor hole by using the high-pressure rotary spraying nozzle when a drill rod of the high-pressure rotary spraying drilling machine rotates around the anchor rod body 1 and gradually rises, and stretching and locking and fixing the anchorage device 2 according to design after the concrete slurry is solidified to form a complete expanded end of the anchor rod body. And the manufacturing of the expansion end anchor rod with the three-layer structure is completed.
The length of the expanded end of the anchor rod system formed in the embodiment is preferably 200 to 500cm, and the diameter of the expanded end of the anchor rod system is preferably 400 to 600mm; the inner diameter of the outer sleeve 3 is 30mm to 60mm. The length of the anchoring section part containing the geopolymer and the expansive concrete is preferably 100 to 300cm, and the length of the free section part consisting of the anchor rod body 1 and the outer sleeve 3 is 500 to 800cm.
In summary, the geopolymer application-based three-layer structure expanded-end anchor rod system and the construction method disclosed in this embodiment include an anchor rod body 1, an anchor 2, an outer sleeve 3, an anchor disc 7, a geopolymer column core 4, an expanded concrete wrapping layer 5 and a soil-concrete curing bonding interface layer; the three-layer structure means that the expansion end part consists of three layers, namely the expansion end part of the anchor rod is sequentially provided with 4 layers of geopolymer column cores, 5 layers of expanded concrete wrapping layers and soil-concrete curing bonding interface layers from the anchor rod body 1 to the outside. The construction process comprises the steps of prefabricating and assembling the geopolymer column core 4, forming holes in the anchor hole, spraying a curing agent, entering the hole in the geopolymer column core, grouting and forming, tensioning and fixing the anchor rod and the like. The working principle of the anchor rod system of the embodiment is as follows: 1. after the anchor rod is stressed, the tension force is transmitted to the geopolymer column core 4 through the anchor rod body 1, the force is diffused to the expanded concrete wrapping layer 5 through the geopolymer column core 4, then is diffused to the soil body through the expanded concrete wrapping layer 5 and the solidified bonding interface layer 8, and is transmitted to the soil body through the three-layer structure step-by-step diffusion; 2. the expanded end of the anchor rod system increases the contact area between the anchoring section and the soil layer so as to increase the frictional resistance between the anchoring section and the soil layer, and the local expansion of the expanded end of the anchor rod system changes the generation mode of the anchoring force, namely the bearing capacity of the front end surface of the expanded end is generated, so that the anchoring force of the anchor rod is greatly improved; 3. after the expanded concrete wrapping layer 5 in the expansion end of the anchor rod is poured and formed, pre-pressure is applied to the soil body, and the frictional resistance between the expansion end and the soil body is enhanced, so that the pulling resistance of the anchor rod is improved; 4. before grouting, a soil curing agent is sprayed at the expanded end, and the expanded concrete wrapping layer 5 and a surrounding soil layer are combined into a spherical shell-shaped cured bonding interface layer 8 after grouting forming, so that the mechanical strength of the surrounding soil body is improved, the bonding force or frictional resistance between the soil body 9 and the surface of the expanded concrete wrapping layer 5 is increased, and the purpose of improving the anchoring force is achieved; 5. the solid waste is used for preparing the geopolymer to replace concrete, so that the anchor rod is more energy-saving and environment-friendly.
Compared with the prior art, the embodiment has the following advantages:
(1) The structure principle is simple, the operation is easy, the feasibility is high, the material is easy to obtain, and the method is more economic.
(2) By adopting a three-layer composite anchor rod structure, the bearing capacity of the anchor rod and the surrounding soil body is fully exerted, and the bearing capacity and the uplift resistance of an anchor rod system are improved.
(3) The solid waste is used for preparing the geopolymer to replace concrete, so that the material is more energy-saving and environment-friendly, and the engineering cost is reduced.
(4) The invention can be widely popularized in the fields of anchor rods and the like.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.
The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the foregoing, the description is not to be taken in a limiting sense.

Claims (8)

1. A three-layer construction enlarged end bolt system comprising:
the bottom end of the anchor rod body (1) is used for being inserted into a soil body (9);
the geopolymer column core (4) is arranged at the bottom end of the anchor rod body (1), the geopolymer column core (4) is prepared by taking industrial solid waste steel slag and mineral powder as raw materials under the combined action of an alkali activator and an additive, the steel slag is medium-high alkalinity converter steel slag, the mineral powder is S95-grade granulated blast furnace mineral powder, and the specific surface area of the steel slag and the mineral powder is 450m 2 The alkali activator adopts feldspar and sodium carbonate in a mass ratio of Na 2 O：SiO 2 1.2 to 1.5, wherein the additive comprises alkali-resistant glass fiber, graphene oxide and sodium sulfate; wherein the mass fraction of the steel slag is 30-60%, the mass fraction of the mineral powder is 40-70%, the mass fraction of the alkali-activator is 3-7% of the mass sum of the steel slag and the mineral powder, the water-gel ratio is 0.25-0.45, the mass fraction of the alkali-resistant glass fiber is 0.1-0.3% of the mass sum of the steel slag and the mineral powder, the mass fraction of the graphene oxide is 0.01-0.03% of the mass sum of the steel slag and the mineral powder, and the mass fraction of the sodium sulfate is 1-1.5% of the mass sum of the steel slag and the mineral powder;
the expanded concrete wrapping layer (5) forms an expanded end and is tightly attached to and wrapped outside the geopolymer column core (4); one or more combinations of bulges, depressions, honeycomb surfaces, spurs or barbs are arranged on the contact surface of the geopolymer column core (4) and the expanded concrete wrapping layer (5);
the solidified bonding interface layer (8) is matched with the shape of the expansion end, and is fixedly bonded between the outer surface of the expanded concrete wrapping layer (5) and the soil body (9); the geopolymer column core (4), the expanded concrete wrapping layer (5) and the solidified bonding interface layer (8) form an anchoring expansion end of an anchor rod system;
ground tackle (2) and anchor disc (7), anchor disc (7) are used for the configuration to be in the bottom of the stock body (1), ground tackle (2) are used for stretch-draw locking the top of the stock body (1).
2. The three-layer enlarged-end bolt system according to claim 1, further comprising an outer sleeve (3), wherein the outer sleeve (3) is sleeved outside the bolt body (1), and the outer sleeve (3) is located above the enlarged anchoring end.
3. The three-layer structure enlarged end anchor system of claim 1, wherein the protrusions are one or more combinations of hemispherical protrusions, square protrusions, or pyramidal protrusions; the depressions are one or a combination of a hemispherical depression, a square depression or a pyramidal depression.
4. A three-layer structure enlarged end anchor rod system according to claim 1 or 2, wherein the raw materials of the expanded concrete cladding (5) comprise sulphoaluminate type expanded cement, an expanding agent, a retarder and a water reducing agent.
5. A three-layer structure enlarged end anchor rod system according to claim 1 or 2, wherein the cured adhesive interface layer (8) is formed by spraying a soil curing agent between the expanded concrete cladding layer (5) and the soil body (9).
6. The three-layer structure expanded end anchor rod system as claimed in claim 1 or 2, wherein the anchor disk (7) is a metal disk with a thickness of 6-15 mm and a diameter of 15-30 cm.
7. A construction method of the three-layer structure enlarged anchor system according to any one of claims 1 to 6, which is characterized by comprising the following steps:
prefabricating a geopolymer column core (4), and assembling the prefabricated geopolymer column core (4) and the bottom end of the anchor rod body (1) together;
performing anchor hole forming construction, and constructing at the bottom end of the anchor hole to form an expanded aperture section;
inserting the anchor rod body (1) assembled with the geopolymer column core (4) into the anchor hole, and spraying a soil curing agent on the enlarged hole diameter section;
injecting a concrete grout mixed expanding agent into the expanded pore diameter section, and forming an anchoring expanded end of the anchor rod body (1) after the concrete grout expands and solidifies;
and (3) installing the anchor (2) on the top of the anchor rod body (1), and tensioning and locking the anchor rod body.
8. The method of constructing a three-layer enlarged end bolt system according to claim 7, wherein the bolt hole is formed by drilling with a high pressure jet drilling machine.
CN202110870390.8A 2021-07-30 2021-07-30 Three-layer structure expanded end anchor rod system and construction method Active CN113585249B (en)

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