阅读说明：本技术 一种偏心弯钩状膨胀式预应力锚固结构及其锚固方法 (Eccentric hook-shaped expansion type pre-stressed anchoring structure and anchoring method thereof ) 是由 刘杰 李政 王天龙 王斌 宋瑞 蔡显灿 莫承林 王昊 郭建祥 陈子悦 汪岩松 于 2021-09-22 设计创作，主要内容包括：本发明提供一种偏心弯钩状膨胀式预应力锚固结构及其锚固方法,该锚固结构包括设置在锚洞内的锚杆,所述锚杆下端设有弯钩,弯钩底部设有圆弧状刚性圆盘,锚洞内沿锚杆自下至上设置N组膨胀水泥砂浆,每组膨胀水泥砂浆上侧均设有硅酸盐水泥砂浆。该锚固结构和方法可以显著提高锚杆的抗拔承载力和抗弯性能,增强锚固段注浆体与地层间的剪切强度和黏结力,提升岩土体的锚固支护效果,且材料简单易得,可操作性强,成本低,推广性强。(The invention provides an eccentric hook-shaped expansion type prestressed anchoring structure and an anchoring method thereof. The anchoring structure and the method can obviously improve the uplift bearing capacity and the bending resistance of the anchor rod, enhance the shearing strength and the cohesive force between the grouting body of the anchoring section and the ground layer, improve the anchoring and supporting effect of the rock-soil body, and have the advantages of simple and easily obtained materials, strong operability, low cost and strong popularization.)

1. The utility model provides an eccentric crotch formula inflation formula prestressed anchorage structure, is including setting up stock (2) in anchor hole (1), its characterized in that, stock (2) lower extreme is equipped with crotch (3), and crotch (3) bottom is equipped with circular-arc rigidity disc (4), and follow stock (2) supreme N group expansion cement mortar (5) that set up from bottom to top in anchor hole (1), every group expansion cement mortar (5) upside all is equipped with silicate cement mortar (6).

2. The prestressed anchoring structure of an eccentric hook-shaped expansion type according to claim 1, wherein a divider plate (7) is provided between said expanded cement mortar (5) and said portland cement mortar (6).

3. The expanding type prestressed anchoring structure of an eccentric hook according to claim 1, wherein said expanded cement mortar (5) has an expanding agent content X_n5% -40%.

4. The prestressed anchoring structure expanded in an eccentric hook shape according to claim 1, wherein basalt fiber is contained in said expanded cement mortar (5) or/and silicate cement mortar (6).

5. The prestressed anchor structure of claim 4, wherein the content of basalt fiber is 1.2kg/m³。

6. The eccentric hook-type expansion-type prestressed anchoring structure according to claim 1, wherein N sets of said expanded cement mortars (5) are filled with an expanding agent content X along the anchor rod (2) from bottom to top_nAnd decreasing sequentially.

7. The eccentric hook-type expansion-type prestressed anchoring structure according to claim 6, wherein when N =2, the expanded cement mortar (5) is poured with the content X of the expanding agent from bottom to top_nDecreasing in turn according to the amount of 10%; when N is present>2, the expanded cement mortar (5) is filled with the content X of the expanding agent from bottom to top_nThe amount of the raw materials is gradually decreased according to the amount of 5 percent.

8. The eccentric hook-type expansion-type prestressed anchoring structure according to claim 1, wherein the height of the expanded cement mortar (5) is 20-30 cm.

9. The prestressed anchoring structure of the eccentric hook-like expansion type according to claim 1, wherein a free end of said hook (3) is inclined to a side away from said anchor rod (2).

10. An anchoring method of an eccentric hook expansion type pre-stressed anchoring structure is characterized by comprising the following steps:

step 1: cleaning a side slope;

step 2: drilling, namely drilling a plurality of anchor holes (1) on the rock slope;

step 3: a hook (3) is manufactured at the lower end of the anchor rod (2), and the arc-shaped rigid disc (4) is connected with the hook (3) through a nut (8) and a spherical stud (9);

step 4: preparing silicate cement mortar and different expanding agent contents X_nN =1,2,3 … N;

step 5: vertically placing the anchor rod (2) into the anchor hole (1), ensuring that the bottom of the anchor rod (2) is positioned in the center of the anchor hole (1), and ensuring that an anchoring body is eccentrically pulled;

step 6: injecting an expanding agent with the mixing amount of X into the anchor hole (1) by grouting equipment₁Until the bottom of the hook (3) to form a first group of expanded cement mortar (5); and after the completion of pouring, arranging a partition plate (7) above the partition plate, pouring silicate cement mortar above the partition plate (7) until the pouring is completed to form a first group of silicate cement mortar (6), and repeatedly pouring the expanded cement mortar (5) and the silicate cement mortar (6) until the pouring of the Nth group of silicate cement mortar (6) is completed.

Technical Field

The invention relates to the technical field of rock and soil anchoring, in particular to an eccentric hook-shaped expansion type pre-stressed anchoring structure and an anchoring method thereof.

Background

In geotechnical engineering, an anchoring technique is an important technique that is widely used. The anchor rod can effectively link the structure with the stratum through the anchor rod buried in the stratum, and the tensile force of the structure is transmitted by means of the shear strength of the anchor rod and the surrounding stratum, so that the stratum is reinforced, the strength of the reinforced rock-soil body is enhanced, the stress state of the rock-soil body is improved, the stability of the structure and the rock-soil body is further maintained, and safety guarantee in a certain degree is provided for engineering construction.

In practical engineering application, the pulling resistance bearing capacity of the anchor rod is an important parameter of engineering design, and the economic efficiency and safety of engineering are directly or indirectly influenced. The anchoring effect of the engineering can be effectively guaranteed by the high uplift bearing capacity of the anchor rod, and the stability and the safety of the engineering can be reduced by the low uplift bearing capacity of the anchor rod. Aiming at the straight-shaped structural metal anchor rods which are frequently used in China at present, the construction method of arranging the anchor rods at the axle center and the ordinary portland cement grouting technology, in some practical engineering applications, the uplift bearing capacity of the anchor rods is lower than the design value due to the limitation of the anchor rods or environmental conditions, so that the anchoring structure is damaged, the anchor rods in rock-soil bodies are invalid, and finally, the local instability and even collapse of the engineering are caused, so that huge loss is caused. Especially aiming at geotechnical slope and chamber anchoring engineering, unstable sliding bodies need higher anchor rod uplift bearing capacity, and at the moment, the anchor rod device and the method which can meet engineering requirements, remarkably improve anchor rod uplift capacity, have high economic feasibility and strong popularization degree are urgently needed by combining the widely applied principle of reinforcing the slope by using prestressed anchor rods.

Disclosure of Invention

The invention aims to solve the technical problem of providing an eccentric hook-shaped expansion type prestressed anchoring structure and an anchoring method thereof, which can obviously improve the pulling-resistant bearing capacity and the bending resistance of an anchor rod, enhance the shearing strength and the adhesive force between an anchoring section grouting body and a ground layer, improve the anchoring and supporting effect of a rock-soil body, and have the advantages of simple and easily obtained materials, strong operability, low cost and strong popularization.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the utility model provides an eccentric crotch formula inflation formula prestressed anchorage structure, is including setting up the stock in the anchor hole, the stock lower extreme is equipped with the crotch, and the crotch bottom is equipped with circular-arc rigidity disc, follows the stock from bottom to top in the anchor hole and sets up N groups of expansion cement mortar, and every group expansion cement mortar upside all is equipped with silicate cement mortar.

In a preferred scheme, a partition plate is arranged between the expanded cement mortar and the silicate cement mortar.

In a preferred embodiment, the content X of the expanding agent in the expanded cement mortar_n5 to 40 percent.

In a preferred embodiment, the expanded cement mortar or/and the portland cement mortar contains basalt fiber.

In a preferable scheme, the content of the basalt fibers is 1.2kg/m³。

Preferred embodimentsIn the process, N groups of the expanded cement mortar are filled with the content X of the expanding agent along the anchor rod from bottom to top_nAnd decreasing sequentially.

In a preferred scheme, when N is 2, the expanded cement mortar is filled with the content X of the expanding agent from bottom to top_nDecreasing in turn according to the amount of 10%; when N is present>2, the content X of the expanding agent is poured into the expanded cement mortar from bottom to top_nThe amount of the raw materials is gradually decreased according to the amount of 5 percent.

In the preferable scheme, the height of the expanded cement mortar is 20-30 cm.

In a preferred embodiment, the free end of the hook is inclined to a side away from the anchor rod.

The invention also provides an anchoring method of the eccentric hook expansion type pre-stressed anchoring structure, which comprises the following steps:

step 1: cleaning a side slope;

step 2: drilling, namely drilling a plurality of anchor holes on the rock slope;

step 3: a hook is manufactured at the lower end of the anchor rod, and the arc-shaped rigid disc is connected with the hook through a nut and a spherical stud;

step 4: preparing silicate cement mortar and different expanding agent contents X_nThe expandable cement mortar of (1), N ═ 1,2,3 … N;

step 5: vertically placing the anchor rod into the anchor hole, ensuring that the bottom of the anchor rod is positioned in the middle of the anchor hole and ensuring that the anchoring body is eccentrically pulled;

step 6: injecting expanded cement mortar with the mixing amount of the expanding agent X1 into the anchor hole through grouting equipment until the bottom of the hook to form a first group of expanded cement mortar; and after the completion of pouring, arranging a partition plate above the partition plate, pouring silicate cement mortar above the partition plate until the completion of pouring to form a first group of silicate cement mortar, and repeatedly pouring the expanded cement mortar and the silicate cement mortar until the completion of pouring of the Nth group of silicate cement mortar.

The invention provides an eccentric hook expansion type pre-stressed anchoring structure and an anchoring method thereof, which effectively solve the problem of insufficient uplift bearing capacity of an anchor rod in engineering application. The prestressed anchor rod is arranged eccentrically innovatively, the hook-shaped or straight hook-shaped structure of the anchor rod is applied to anchoring engineering, a circular-arc rigid disc is used, a traditional tension type anchor rod is converted into a pressure type anchor rod, an expanding agent and basalt fibers are applied to cement mortar, and particularly in a tension area of an anchoring body, so that the toughness, the durability, the impermeability and the freeze-thaw resistance of the anchoring body can be effectively improved while the pulling bearing capacity of the anchor rod is remarkably enhanced. The anchoring structure and the method are simple, economical, high in popularization, simple and easily available in materials, high in operability, low in cost and high in popularization, and can be widely applied to the engineering fields of slope stabilizing engineering, tunnel and underground supporting engineering, deep foundation pit supporting engineering, dam body reinforcing engineering, ground high tower or overhead structure reinforcing, road and bridge foundation reinforcing engineering, roadway and mine supporting engineering, existing structure reinforcing and strengthening and the like.

Drawings

The invention is further illustrated with reference to the accompanying drawings and examples:

FIG. 1 is a diagram of an anchoring structure applied to a soil slope according to a first embodiment of the present invention;

FIG. 2 is an enlarged view taken at A in FIG. 1;

FIG. 3 is a schematic view of the mounting of a circular arc shaped rigid disk;

FIG. 4 is a schematic diagram of the stress analysis of the apparatus of the present invention in a slope;

FIG. 5 is a graph of the force bending moment of the apparatus of the present invention in a side slope;

FIG. 6 is a schematic view of the anchor of the hook in a right angle configuration;

FIG. 7 is a schematic view of a preferred hook of the present invention;

FIG. 8 is a diagram of the application of the anchoring structure in a rocky slope according to a second embodiment of the present invention;

fig. 9 is a diagram of the use of the anchoring structure in chamber anchoring in accordance with example three of the present invention;

in the figure: anchor hole 1, anchor rod 2, hook 3, circular arc rigid disc 4, expanded cement mortar 5, portland cement mortar 6, division plate 7, nut 8, spherical stud 9 and latent slip surface 10.

Detailed Description

Example 1: as shown in fig. 1 to 3, the eccentric hook-shaped expansion type prestressed anchoring structure comprises an anchor rod 2 arranged in an anchor hole 1, wherein a hook 3 is arranged at the lower end of the anchor rod 2, an arc-shaped rigid disc 4 is arranged at the bottom of the hook 3, the arc-shaped rigid disc 4 is bent upwards, N groups of expansion cement mortar 5 are arranged in the anchor hole 1 from bottom to top along the anchor rod 2, and silicate cement mortar 6 is arranged on the upper side of each group of expansion cement mortar 5.

Because the lower extreme of stock 2 is equipped with crotch 3, with the eccentric settling in anchor hole 1 of stock popularization nature, showing the bending resistance who has improved stock 2.

When the anchor rod is used specifically, the hook 3 can be a right-angle hook as shown in fig. 6 or an arc hook as shown in fig. 7, different eccentric distances are set according to different engineering characteristics, and the pulling-resistant bearing capacity and the bending resistance of the anchor rod can be improved in a targeted manner.

The iron disc can be selected for use to circular-arc rigidity disc 4 that sets up in crotch 3 bottom, through setting up circular-arc rigidity disc 4, can increase lifting surface area on the one hand, improves the resistance to plucking bearing capacity of stock, and on the other hand can convert pulling force type stock into pressure type stock, further improves the resistance to plucking bearing capacity and the life cycle of stock.

Through setting up multiunit expansion cement mortar 5, make the multilayer that the anchor structure formed the trapezoidal form expand the head, produce and expand first effect, increase the shear strength and the resistance to plucking bearing capacity of stock with ground body interface frictional resistance.

Meanwhile, the application of the expanded cement mortar greatly improves the water resistance and stability of the anchoring body, enhances the anchoring effect and effectively shortens the construction period.

The alternative use of ordinary portland cement mortar and expanded cement mortar can effectively reduce the use of expanding agent on the one hand, practices thrift the cost, and on the other hand can strengthen the intensity of anchor, guarantees anchor's stability.

Preferably, a partition plate 7 is provided between the expanded cement mortar 5 and the silicate cement mortar 6.

The partition plate 7 is used for separating silicate cement mortar 6 from expanded cement mortar 5, so that the expansion section can fully play a role of expansion, and the ordinary silicate cement mortar 6 plays a role of a cement anchoring section to form a string-shaped anchoring body, thereby improving the pulling resistance. Meanwhile, the partition plates 7 are arranged at intervals, so that the use amount of the expanded cement mortar can be reduced, and the expanded cement mortar is more economical.

Preferably, the content X of the expanding agent in the expanded cement mortar 5_n5% -40%, the expanding agent can be calcium sulphoaluminate or calcium oxide expanding agent, such as: alunite expanding agent (mainly comprising alunite and anhydrous gypsum or dihydrate gypsum) or CSA expanding agent (mainly comprising anhydrous calcium sulphoaluminate).

The expanded cement mortar 5 and/or the silicate cement mortar 6 contain basalt fibers. The basalt fiber with a certain content added into the cement mortar can enhance the toughness of the anchoring body, effectively prevent the expansion of the microcracks of the cement mortar, enhance the anti-permeability and anti-freeze-thaw performance of the anchoring body, improve the durability of the anchoring body, and meanwhile, on the premise of the eccentricity of the anchor rod, more expanding agents and basalt fiber can be added at the tension part of the anchoring body in a targeted manner, so that the tensile strength of the anchoring body is enhanced, and the stability of the anchoring body is ensured. Under the condition of different stresses of the anchoring structure, a region with larger stress of the anchoring structure can be found out by utilizing stress analysis and a stress bending moment diagram, the stress tensile treatment is emphasized, and more basalt fibers, expanding agents and the like are added into the region. The content of the expanding agent in the tension area is 20-40% more than that in the corresponding compression area, especially in the area with large stress bending moment. Wherein, the formula for calculating the bending moment is as follows:

wherein x is the distance from the side slope retaining structure;

q is the side reaction force to which the anchor segment is subjected.

The content of the basalt fiber is selected to be 1.2kg/m³。

N groups of the expanded cement mortar 5 are filled with the content X of the expanding agent along the anchor rod 2 from bottom to top_nAnd decreasing sequentially.

When N is 2, the expanded cement mortar 5 is poured with the content X of the expanding agent from bottom to top_nIn an amount of 10%Sequentially decreasing; when N is present>2, the expanded cement mortar 5 is filled with the content X of the expanding agent from bottom to top_nThe amount of the raw materials is gradually decreased according to the amount of 5 percent. The decreasing is to ensure that the mixing amount of the expanding agent of the injected expanding cement paste is different, so as to form a multi-layer layered expanding head of the anchoring body, form an expanding head effect and greatly improve the pulling resistance of the anchor rod. Meanwhile, the contact probability of the anchor rod with water and air can be greatly reduced, the durability of the anchor rod is improved, and therefore the pulling resistance of the anchor rod is greatly improved, and the service life of the anchor rod is prolonged.

Preferably, the height of the expanded cement mortar 5 is 20-30 cm. The selection is specifically carried out according to engineering test experience.

An anchoring method of an eccentric hook expansion type pre-stressed anchoring structure comprises the following steps: step 1: and (3) cleaning the side slope, carrying out engineering geological investigation and analytical research aiming at the soil side slope, and determining the position, scale, form, size and stable state of the potential sliding surface 10. Determining the engineering property and the stability importance degree of the soil slope, selecting a reasonable failure criterion and a safety factor, and determining the anchor rod layout, the installation angle and the prestress value on the basis.

Step 2: and (3) drilling, namely drilling a plurality of anchor holes 1 on the rock slope, taking the anchor holes 1 with the height of 1.8m and the diameter of 6cm as an example.

Step 3: design stock size is length 2m, and external diameter 22mm adopts the preparation of high strength finish rolling twisted steel, and the crooked preparation crotch 3 of 2 lower extremes of stock is connected circular-arc rigidity disc 4 through nut 8 and ball stud 9 and crotch 3 to the stock stability is calculated by inspection.

Step 4: preparing silicate cement mortar and different expanding agent contents X_nThe expandable cement mortar of (1), 2,3 … 7. Ordinary portland cement with the strength grade of 42.5 is adopted, wherein the sand is standard sand, and the mixing proportion of the mortar is m (cement): m (standard sand): m (water) ═ 450: 1350: 225 and incorporate 1.2kg/m³Basalt fibers; different contents X of expanding agent are prepared in ordinary portland cement_nN-1, 2,3, …,7, the content of expanding agent being 40%, 35%, 30%, 25%, 20%, 15%, 10% in sequence, while ensuring that the expanding agent in the tensioned zone of the anchor containsIn an amount of more than 30% of the corresponding compressed area. Under different stress conditions of the anchoring section, different areas under tension and compression need to be specifically analyzed according to engineering. Under the stress condition as shown in fig. 4 and 5, the upper end of the anchoring section is pulled, and the lower end is compressed.

Step 5: the anchor rod 2 is vertically placed into the anchor hole 1, the bottom of the hook 3 is ensured to be positioned in the center of the anchor hole 1, and the eccentric tension of the anchoring body is ensured.

Step 6: injecting expanded cement mortar with the mixing amount of the expanding agent X1 into the anchor hole 1 through grouting equipment until the bottom of the hook 3 to form a first group of expanded cement mortar 5; after the completion of the pouring, the partition plate 7 is placed above the partition plate 7, silicate cement mortar is poured above the partition plate 7 until the completion of the pouring to form the first set of silicate cement mortar 6, and the pouring of the expanded cement mortar 5 and the silicate cement mortar 6 is repeated until the completion of the pouring of the seventh set of silicate cement mortar 6.

Example 2: unlike embodiment 1, the free end of the hook 3 is inclined to the side away from the anchor rod 2 as shown in fig. 7 and 8. Through setting up the crotch 3 into outside bending, make the stock have extremely strong suitability in hard rock mass, can reach the effect of "borrow hard", cause the stock to receive the counter-force of hard rock mass, further improved the anchor bearing capacity of stock, reinforcing anchor effect can guarantee the anchor effect of anchor engineering for a long time steadily. Especially in hard rock formations.

Specifically, as shown in fig. 7, the curved diameter of the hook 3 is 3.5 times the diameter of the anchor rod 2.

Example 3: different from the embodiments 1 and 2, as shown in fig. 9, taking an anchor hole with a height of 1.8m and a diameter of 6cm as an example, the hook 3 is arranged to be bent outwards, after the anchoring work is finished, under the action of the anchoring force of the anchor rod and the deformation movement of the geological body, the hook 3 of the anchor rod 2 is gradually propped against the hard rock body, so that the anchor rod is subjected to the counter force of the hard rock body, the anchoring bearing capacity of the anchor rod is further improved, and the anchoring effect is enhanced.

The eccentric hook-shaped expansion type prestressed anchoring structure can obviously improve the anti-pulling bearing capacity of the anchor rod and effectively solve the problem that the anti-pulling bearing capacity of the anchor rod is insufficient in engineering application. The prestressed anchor rod is arranged eccentrically innovatively, the hook-shaped or straight hook-shaped structure of the anchor rod is applied to anchoring engineering, a circular-arc rigid disc is used, a traditional tension type anchor rod is converted into a pressure type anchor rod, an expanding agent and basalt fibers are applied to cement mortar, and particularly in a tension area of an anchoring body, so that the toughness, the durability, the impermeability and the freeze-thaw resistance of the anchoring body can be effectively improved while the pulling bearing capacity of the anchor rod is remarkably enhanced. The anchoring structure and the method are simple, economical, high in popularization, simple and easily available in materials, high in operability, low in cost and high in popularization, and can be widely applied to the engineering fields of slope stabilizing engineering, tunnel and underground supporting engineering, deep foundation pit supporting engineering, dam body reinforcing engineering, ground high tower or overhead structure reinforcing, road and bridge foundation reinforcing engineering, roadway and mine supporting engineering, existing structure reinforcing and strengthening and the like.