Secondary grouting hole and design method thereof, and foundation bolt mounting structure and method

Abstract

The invention discloses a secondary grouting hole and a design method thereof, and the design method comprises the following steps: designing the secondary grouting hole into a form with a small upper part and a large lower part, and designing the slope i of the hole wall of the secondary grouting hole according to 1: 20-1: 10. The invention further discloses a foundation bolt installation structure and method, and the installation method comprises the steps that a concrete base of an equipment foundation is manufactured, and the secondary grouting hole is reserved in the concrete base; and the foundation bolts are placed in the secondary grouting holes, and secondary grouting materials are poured into the secondary grouting holes, so that the foundation bolts are fixedly arranged in the secondary grouting holes. According to the method, the situation that the tension bearing capacity of the foundation bolt is reduced due to bonding damage between the secondary grouting material and the hole wall when the foundation bolt is tensioned can be avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of building structure design, and particularly relates to a secondary grouting hole, a design method thereof, an anchor bolt installation structure and a method. Background Art

[0002] To ensure the precise positioning of anchor bolts in equipment foundations, anchor bolt holes are often reserved in the equipment foundation first, and then the anchor bolts are implanted in the form of secondary grouting. For the commonly used straight-wall secondary grouting holes, when the anchor bolts are in tension, the bond force between the secondary grouting material and the hole wall needs to be relied on to resist the tension force of the anchor bolts. Since this bond force is greatly affected by construction factors (such as interface treatment conditions, grouting material properties, and curing measures) and is not easy to determine. Referring to Table 2 of the Design Code for Nuclear Safety-Related Concrete Structures in Pressurized Water Reactor Nuclear Power Plants NB / T 20012-2019, the bond strength between the secondary grouting material and the hole wall can be taken as 0.3 N / mm 2 , multiplying this value by the lateral surface area of the anchor bolt hole can obtain the bond force between the secondary grouting material and the hole wall. Since this value is small, bond failure between the secondary grouting material and the hole wall is likely to occur when the anchor bolts are in tension, thereby reducing the tensile bearing capacity of the anchor bolts. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a secondary grouting hole suitable for tensile anchor bolts in equipment foundations, a design method thereof, an anchor bolt installation structure and a method, which can avoid bond failure between the secondary grouting material and the hole wall when the anchor bolts are in tension and reduce the tensile bearing capacity of the anchor bolts, aiming at the above deficiencies existing in the prior art.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] According to the first aspect of the present invention, a design method for a secondary grouting hole is provided, including: designing the secondary grouting hole in a form with a smaller upper part and a larger lower part, and designing the hole wall slope i of the secondary grouting hole as 1:20 to 1:10.

[0006] Optionally, this method further includes: treating the hole wall of the secondary grouting hole according to the requirements of construction joints, and making the friction coefficient between the hole wall and the secondary grouting material ≥ 0.6.

[0007] Optionally, the upper opening of the secondary grouting hole is a square with a side length ≥ 100 mm or a circle with a diameter ≥ 100 mm.

[0008] According to the second aspect of the present invention, a secondary grouting hole is provided, which is made according to the above-mentioned design method.

[0009] Optionally, the axial section of the secondary grouting hole is trapezoidal.

[0010] According to the third aspect of the present invention, a method for installing anchor bolts is provided, including:

[0011] Fabricate a concrete pedestal for the equipment foundation, and reserve the secondary grouting holes described above in the concrete pedestal;

[0012] Place the anchor bolt in the secondary grouting hole, and pour secondary grouting material into the secondary grouting hole to fix the anchor bolt in the secondary grouting hole.

[0013] Optionally, the tensile force borne by the anchor bolt is borne by the sum of the vertical component of the normal pressure between the secondary grouting material and the wall of the secondary grouting hole and the vertical component of the frictional force between the secondary grouting material and the wall of the secondary grouting hole.

[0014] Optionally, the normal pressure between the secondary grouting material and the wall of the secondary grouting hole is calculated in the following manner:

[0015] N = Sf cc

[0016] In the formula, S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation.

[0017] According to the fourth aspect of the present invention, an anchor bolt installation structure is provided, including a concrete pedestal. The secondary grouting holes described above are provided in the concrete pedestal, and the anchor bolt is fixed in the secondary grouting hole by pouring secondary grouting material.

[0018] Optionally, the sum of the vertical component of the normal pressure between the secondary grouting material and the wall of the secondary grouting hole and the vertical component of the frictional force between the secondary grouting material and the wall of the secondary grouting hole ≥ the tensile force borne by the anchor bolt.

[0019] Optionally, the normal pressure between the secondary grouting material and the wall of the secondary grouting hole is calculated in the following manner:

[0020] N = Sf cc

[0021] In the formula, S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation.

[0022] Advantageous effects:

[0023] The present invention enables the tensile force F on the tensile anchor bolts of the equipment foundation to be borne by the sum of the vertical components of the normal pressure between the secondary grouting material and the hole wall and the vertical components of the frictional force between the secondary grouting material and the hole wall, thereby ignoring the bond force between the secondary grouting material and the hole wall, which is greatly affected by construction factors and difficult to determine. Compared with the traditional design of the secondary grouting hole with a straight hole wall, the present invention is safer and more reliable, and can avoid the occurrence of the reduction of the tensile bearing capacity of the anchor bolt due to the insufficient bond force between the secondary grouting material and the hole wall in the straight hole wall secondary grouting hole. Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the secondary grouting hole according to an embodiment of the present invention;

[0025] Figure 2 is a schematic structural diagram of the square secondary grouting hole according to an embodiment of the present invention;

[0026] Figure 3 is a schematic structural diagram of the circular secondary grouting hole according to an embodiment of the present invention.

[0027] In the figure: 1-hole wall; 2-anchor bolt; 3-secondary grouting material. Detailed Embodiments

[0028] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "upper" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0030] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0031] Aiming at the problems that the bonding force between the secondary grouting material and the hole wall is prone to be insufficient in traditional designs, resulting in a reduction in the tensile bearing capacity of anchor bolts, the present invention discloses a design method for secondary grouting holes, including: designing the secondary grouting holes in a form that is smaller at the top and larger at the bottom; designing the hole wall slope i of the secondary grouting holes according to 1:20 to 1:10.

[0032] Furthermore, the present invention also discloses a secondary grouting hole, which is made according to the above-mentioned design method.

[0033] Furthermore, the present invention also discloses an installation method for anchor bolts, including: making a concrete base for the equipment foundation and reserving the above-mentioned secondary grouting holes in the concrete base; placing the anchor bolts in the secondary grouting holes and pouring secondary grouting material into the secondary grouting holes to fix the anchor bolts in the secondary grouting holes.

[0034] Furthermore, the present invention also discloses an installation structure for anchor bolts, including a concrete base, in which the above-mentioned secondary grouting holes are provided, and the anchor bolts are fixed in the secondary grouting holes by pouring secondary grouting material.

[0035] The present invention enables the tensile force F borne by the tensile anchor bolts of the equipment foundation to be borne by the sum of the vertical component of the normal pressure between the secondary grouting material and the hole wall and the vertical component of the frictional force between the secondary grouting material and the hole wall, thereby ignoring the bonding force between the secondary grouting material and the hole wall, which is greatly affected by construction factors and difficult to determine. Compared with the traditional design of secondary grouting holes with straight hole walls, the present invention is safer and more reliable, and can avoid the occurrence of the situation where the tensile bearing capacity of the anchor bolts is reduced due to insufficient bonding force between the secondary grouting material and the hole wall in the straight hole wall secondary grouting holes.

[0036] Embodiment 1

[0037] As Figure 1 shown, this embodiment discloses a design method for secondary grouting holes for installing tensile anchor bolts 2 of the equipment foundation. The method includes: designing the secondary grouting holes in a form that is smaller at the top and larger at the bottom; designing the hole wall slope i of the secondary grouting holes according to 1:20 to 1:10. For example, the hole wall slope i can be 1:10, or it can be 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, etc., but not limited thereto.

[0038] In some embodiments, the hole depth h of the secondary grouting hole ≥ 10d0 + 100 mm (d0 is the diameter of the anchor bolt).

[0039] In some embodiments, the method further includes: treating the hole wall 1 of the secondary grouting hole according to the requirements of the construction joint, and making the friction coefficient between the hole wall and the secondary grouting material ≥ 0.6, so as to increase the friction force between the secondary grouting material and the hole wall of the secondary grouting hole, improve the tensile bearing capacity of the anchor bolt, and ensure the safety and reliability of the anchor bolt.

[0040] Specifically, the tensile force F on the tensile anchor bolt 2 of the equipment foundation is borne by the sum of the vertical component force N·sin(arctan(i)) of the normal pressure between the secondary grouting material 3 and the hole wall 1 and the vertical component force 0.6N·cos(arctan(i)) of the frictional force between the secondary grouting material and the hole wall, that is, F ≤ N·sin(arctan(i)) + 0.6N·cos(arctan(i)).

[0041] In some embodiments, the normal pressure between the secondary grouting material and the hole wall 1 of the secondary grouting is calculated as follows:

[0042] N = Sf cc

[0043] In the formula, S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation. In this embodiment, it is taken as 0.85 times the design value of the axial compressive strength of the concrete f c multiplied by 0.85.

[0044] In some embodiments, as Figure 2 、 Figure 3 shown, the upper opening of the secondary grouting hole is a square with a side length ≥ 100 mm or a circle with a diameter ≥ 100 mm. The specific shape and size are determined according to the form of the embedded anchor bolt, which will not be elaborated here one by one. In this way, it can not only provide a certain position adjustment space for the anchor bolt, but also ensure the accurate positioning of the anchor bolt and the dense pouring of the secondary grouting material in the anchor bolt hole.

[0045] Example 2

[0046] As Figure 1 shown, this embodiment discloses a secondary grouting hole, which is made according to the above-mentioned design method. The secondary grouting hole is smaller at the top and larger at the bottom, and the hole wall slope i is 1:20 to 1:10.

[0047] In some embodiments, the hole depth h of the secondary grouting hole ≥ 10d0 + 100 mm (d0 is the diameter of the anchor bolt).

[0048] In some embodiments, as Figure 2 、 Figure 3As shown, the upper opening of the secondary grouting hole is a square with a side length ≥ 100 mm or a circle with a diameter ≥ 100 mm. The specific shape and size are determined according to the form of the embedded anchor bolts, which will not be elaborated here one by one.

[0049] In some embodiments, the axial section of the secondary grouting hole is preferably trapezoidal.

[0050] In some embodiments, the friction coefficient between the hole wall 1 of the secondary grouting hole and the secondary grouting material 3 is ≥ 0.6. The tensile force F on the tensile anchor bolt 2 of the equipment foundation is borne by the sum of the vertical component force N·sin(arctan(i)) of the normal pressure between the secondary grouting material and the hole wall and the vertical component force 0.6N·cos(arctan(i)) of the frictional force between the secondary grouting material and the hole wall, and F ≤ N·sin(arctan(i)) + 0.6N·cos(arctan(i)).

[0051] Specifically, the normal pressure between the secondary grouting material and the secondary grouting hole wall is calculated as follows:

[0052] N = Sf cc

[0053] In the formula, S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation. In this embodiment, it is taken as 0.85 times the design value of the axial compressive strength of the concrete f c multiplied by 0.85.

[0054] Embodiment 3

[0055] This embodiment discloses a method for installing anchor bolts, including:

[0056] Fabricate the concrete base of the equipment foundation and reserve the above-mentioned secondary grouting hole in the concrete base, that is, the secondary grouting hole is smaller at the top and larger at the bottom, and the slope i of the hole wall of the secondary grouting hole is 1:20 to 1:10;

[0057] As Figure 1 shown, place the anchor bolt 2 in the secondary grouting hole and pour the secondary grouting material 3 into the secondary grouting hole to fix the anchor bolt 2 in the secondary grouting hole.

[0058] In this embodiment, the tensile force on the anchor bolt 2 is borne by the sum of the vertical component force of the normal pressure between the secondary grouting material 3 and the secondary grouting hole wall 1 and the vertical component force of the frictional force between the secondary grouting material and the secondary grouting hole wall, that is, the sum of the component forces of the normal pressure and the frictional force between the secondary grouting material 3 and the hole wall 1 is used to resist the tensile force on the anchor bolt.

[0059] In some embodiments, the hole depth h of the secondary grouting hole is ≥ 10d0 + 100 mm (d0 is the diameter of the anchor bolt).

[0060] In some embodiments, such as Figure 2 , Figure 3 shown, the upper opening of the secondary grouting hole is a square with a side length ≥ 100 mm or a circle with a diameter ≥ 100 mm. The specific shape and size are determined according to the form of the embedded anchor bolts, which will not be elaborated here one by one.

[0061] In some embodiments, the normal pressure between the secondary grouting material 3 and the wall 1 of the secondary grouting hole is calculated as follows:

[0062] N = Sf cc

[0063] In the formula, S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation. In this embodiment, it is taken as the concrete axial compressive strength design value f c multiplied by 0.85.

[0064] In some embodiments, the friction coefficient between the wall 1 of the secondary grouting hole and the secondary grouting material 3 is ≥ 0.6. The bottom of the hole should be cleaned thoroughly without loose aggregate, floating slurry, debris, accumulated water, etc. Then, position the anchor bolt 2 according to the design requirements, and inject the secondary grouting material 3 into the anchor bolt hole. The secondary grouting material 3 should meet the relevant provisions of the "Technical Specification for Application of Cementitious Grouting Materials" GB / T 50448-2015. The tension F borne by the tensile anchor bolt of the equipment foundation is borne by the sum of the vertical component force N·sin(arctan(i)) of the normal pressure between the secondary grouting material and the hole wall and the vertical component force 0.6N·cos(arctan(i)) of the friction force between the secondary grouting material and the hole wall, that is, F ≤ N·sin(arctan(i)) + 0.6N·cos(arctan(i)).

[0065] Example 4

[0066] Such as Figure 1 shown, this embodiment discloses an anchor bolt installation structure, including a concrete base. The secondary grouting hole described above is provided in the concrete base, that is, the secondary grouting hole is smaller at the top and larger at the bottom, and the slope i of the wall of the secondary grouting hole is 1:20 to 1:10. The anchor bolt 2 is fixedly arranged in the secondary grouting hole by pouring the secondary grouting material 3.

[0067] In this embodiment, the sum of the vertical component force of the normal pressure between the secondary grouting material 3 and the wall 1 of the secondary grouting hole and the vertical component force of the friction force between the secondary grouting material and the wall of the secondary grouting hole is ≥ the tension borne by the anchor bolt.

[0068] In some embodiments, the normal pressure between the secondary grouting material 3 and the wall 1 of the secondary grouting hole is calculated as follows:

[0069] N = Sf cc

[0070] Wherein, S is the side wall area of the secondary grouting hole; f cc is the designed axial compressive strength value of the plain concrete of the equipment foundation. In this embodiment, it is taken as the concrete axial compressive strength design value f c multiplied by 0.85.

[0071] In some embodiments, the friction coefficient between the hole wall 1 of the secondary grouting hole and the secondary grouting material 3 is ≥ 0.6. The tension F received by the tensile anchor bolt of the equipment foundation is borne by the sum of the vertical component force N·sin(arctan(i)) of the normal pressure between the secondary grouting material and the hole wall and the vertical component force 0.6N·cos(arctan(i)) of the friction force between the secondary grouting material and the hole wall, that is, F ≤ N·sin(arctan(i)) + 0.6N·cos(arctan(i)).

[0072] In some embodiments, the hole depth h of the secondary grouting hole is ≥ 10d0 + 100 mm (d0 is the diameter of the anchor bolt).

[0073] In some embodiments, as Figure 2 , Figure 3 shown, the upper opening of the secondary grouting hole is a square with a side length ≥ 100 mm or a circle with a diameter ≥ 100 mm. The specific shape and size are determined according to the form of the embedded anchor bolt, and will not be elaborated here one by one.

[0074] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A design method for secondary grouting holes, characterized in that, Comprising: Design the secondary grouting hole in a form that is smaller at the top and larger at the bottom, and design the hole wall slope i of the secondary grouting hole as 1:20 to 1:

10.

2. The design method of the secondary grouting hole according to claim 1, characterized in that Also comprising: Treat the hole wall of the secondary grouting hole according to the requirements of the construction joint, and make the friction coefficient between the hole wall and the secondary grouting material ≥ 0.

6.

3. The design method of the secondary grouting hole according to claim 1, characterized in that The upper opening of the secondary grouting hole is a square with a side length ≥ 100 mm or a circle with a diameter ≥ 100 mm.

4. A secondary grouting hole, characterized in that, Manufactured according to the design method described in any one of claims 1 to 3.

5. The secondary grouting hole according to claim 4, characterized in that, The axial section of the secondary grouting hole is trapezoidal.

6. A method for installing anchor bolts, characterized in that, Comprising: Manufacture the concrete pedestal of the equipment foundation, and reserve the secondary grouting hole described in claim 4 or 5 in the concrete pedestal; Place the anchor bolt in the secondary grouting hole, and pour the secondary grouting material into the secondary grouting hole to fix the anchor bolt in the secondary grouting hole.

7. The method for installing the anchor bolt according to claim 6, characterized in that, The tensile force borne by the anchor bolt is borne by the sum of the vertical component of the normal pressure between the secondary grouting material and the hole wall of the secondary grouting hole and the vertical component of the frictional force between the secondary grouting material and the hole wall of the secondary grouting hole.

8. The method for installing the anchor bolt according to claim 7, wherein The normal pressure between the secondary grouting material and the hole wall of the secondary grouting hole is calculated in the following manner: N = Sf cc Where S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation.

9. An anchor bolt installation structure, comprising a concrete base, characterized in that, The concrete pedestal is provided with the secondary grouting hole described in claim 4 or 5, and the anchor bolt is fixed in the secondary grouting hole by pouring the secondary grouting material.

10. The anchor bolt installation structure according to claim 9, characterized in that, The sum of the vertical component of the normal pressure between the secondary grouting material and the hole wall of the secondary grouting hole and the vertical component of the frictional force between the secondary grouting material and the hole wall of the secondary grouting hole ≥ the tensile force borne by the anchor bolt.

11. The anchor bolt installation structure according to claim 10, characterized in that, The normal pressure between the secondary grouting material and the hole wall of the secondary grouting hole is calculated in the following manner: N = Sf cc Where S is the side wall area of the secondary grouting hole; f cc is the design value of the axial compressive strength of the plain concrete of the equipment foundation.

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