Rock wall crane beam rock wall overbreakage reinforcing structure and construction method thereof

Abstract

This invention belongs to the field of water conservancy, hydropower, and engineering construction, and provides a rock wall crane beam rock wall over-excavation reinforcement structure and its construction method. The technical solution includes a crane beam and at least one anchor rod set on the rock wall excavation surface. A groove is set at the position of the anchor rod on the rock wall excavation surface, and a rock wall side-embedded plate is set in the groove. The crane beam side-embedded plate is fixed to the rock wall side-embedded plate, and the anchor rod passes through the rock wall side-embedded plate and the crane beam side-embedded plate and is fixed to the crane beam. The invention adopts structural measures to improve the shear resistance of the anchor rod at the contact surface and applies the groove and the embedded plate to the reinforcement mechanism.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy and hydropower and engineering construction, and particularly relates to a rock wall crane beam rock wall over-excavation reinforcement structure and its construction method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In underground powerhouses such as hydroelectric power stations and pumped storage power stations, rock-wall crane beams are often used instead of traditional column-supported crane beams because they eliminate the need for crane support columns, allowing for a smaller span in the underground powerhouse, thus reducing excavation volume, saving costs, and shortening construction time. Rock-wall crane beams, also known as rock-anchored beams, are structures that use anchor bolts to anchor reinforced concrete beams to the rock walls of the underground powerhouse cavern. The principle of rock-wall crane beams is to use grouting anchor bolts to lock the reinforced concrete crane beam at the contact surface between the underground powerhouse rock wall and the crane beam. The anchor bolts and the rock wall contact surface act as a medium to transfer all the forces on the beam to the rock mass near the cavern wall, allowing the crane beam and the surrounding rock to interact and share the load. The stability of the anchor bolts and the contact surface determines the stability, safety, and reliability of the rock-wall crane beam structure.

[0004] During the excavation of underground powerhouse caverns, a vertical platform or a sloping surface with a certain range of rock wall angles is formed at the location of the rock wall crane beam. The concrete crane beam is placed on the platform or sloping surface. Due to the difficulty in forming the platform during excavation, the sloping surface is often used in actual engineering. In the actual excavation process of underground powerhouse caverns, although measures such as smooth blasting, controlling the amount of explosives, and setting isolation layers in layered excavation are taken to ensure that the excavated rock wall angle is within the allowable range, in local areas with poor surrounding rock conditions such as well-developed joints, faults, or fractured sections, there is often a serious lack of rock beam support, and even phenomena such as loosening of the surrounding rock, opening of rock mass fissures, and the appearance of spalling or plate-like cracks may occur, leading to a certain degree of deterioration of the surrounding rock conditions. In this case, it is necessary to reinforce the rock wall at the location of the rock wall crane beam. The commonly used method is to backfill with concrete and add anchor bolts and attached walls (columns) for reinforcement. When designing the reinforcement, finite element analysis software is usually used to perform finite element analysis on the reinforcement scheme. There are also relevant statements in the specifications. Finite element analysis should be performed for large-scale rock wall crane beams or those with complex geological conditions.

[0005] The inventors discovered that current finite element analysis (FEM) analyses of reinforcement schemes often simplify anchor bolts to cable elements, leading to an inability to accurately simulate the shear force borne by the anchor bolts. Furthermore, the shear strength of anchor bolts is not high. Standards specify ranges for the rock face angle β and the beam bottom inclination angle β0, aiming to ensure that the shear force borne by the anchor bolts is not excessive. Therefore, ensuring sufficient shear resistance at the anchor bolt location is crucial when reinforcing rock faces. In rock face areas with adverse geological conditions, the formation of the rock face base is difficult, and the rock face angle after excavation is typically very small. The smaller the rock face angle, the greater the shear force the anchor bolts must withstand. This can lead to shear failure of the anchor bolts, thereby affecting the structural safety of the rock face crane beam. Summary of the Invention

[0006] In order to solve at least one of the technical problems existing in the background art, the first aspect of the present invention provides a construction method for a rock wall crane beam rock wall over-excavation reinforcement structure, which adopts structural measures to improve the shear resistance of the anchor at the rock wall contact surface and applies grooves and embedded plates to the reinforcement mechanism.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a rock wall crane beam rock wall over-excavation reinforcement structure, including a crane beam and at least one anchor rod disposed on the rock wall excavation surface. A groove is provided at the location of the anchor rod on the rock wall excavation surface, and a rock wall side-embedded plate is disposed in the groove. A crane beam side-embedded plate is fixedly connected to the rock wall side-embedded plate. The anchor rod passes through the rock wall side-embedded plate and the crane beam side-embedded plate. An anchor bar is welded to the crane beam side-embedded plate, and the anchor bar is anchored into the backfill concrete between the crane beam and the rock wall excavation surface.

[0009] As one implementation method, grooves are set at the positions of anchor bolts on the rock wall excavation surface, based on the angle of the formed rock wall after over-excavation.

[0010] As one implementation method, if the angle of the formed rock wall after over-excavation is less than 30°, a first anchor bolt is set on the excavated surface of the rock wall, and a groove is set at the first anchor bolt.

[0011] If the angle of the formed rock wall after over-excavation is greater than 30°, a first anchor bolt and a second anchor bolt are installed on the excavated rock wall surface. The first anchor bolt is installed at the upper end of the excavated rock wall surface, and the second anchor bolt is installed at the lower end of the excavated rock wall surface. Both the first and second anchor bolts have grooves. As one embodiment, the second anchor bolt is a reinforcing anchor bolt, and the first anchor bolt is a rock wall crane beam anchor bolt.

[0012] As one implementation method, the arrangement of the grooves depends on the anchor bolt position, including quincunx, straight, or rectangular arrangements.

[0013] In one implementation, the anchor bolt is replaced by an anchor cable or a prestressed anchor bolt.

[0014] To address the aforementioned problems, a second aspect of the present invention provides a method for reinforcing rock wall over-excavation of a rock wall crane beam, which employs structural measures to improve the shear resistance of the anchor bolts at the contact surface with the surrounding rock, and applies grooves and embedded plates to the reinforcement method.

[0015] Includes the following steps:

[0016] Step 1: Clean the rock wall excavation surface and set grooves at the anchor bolt positions on the rock wall excavation surface according to the required rock wall angle after over-excavation;

[0017] Step 2: Place the rock wall side-embedded plate in the groove, pass the anchor rod through the rock wall side-embedded plate, and weld the anchor rod to the rock wall side-embedded plate. Pass the anchor rod through the crane beam side-embedded plate, and weld the rock wall side-embedded plate to the crane beam side-embedded plate.

[0018] Step 3: Finally, backfill concrete and crane beam concrete are poured.

[0019] In one implementation method, step 1 involves setting grooves at the anchor bolt positions on the rock wall excavation surface according to the required angle of the rock wall after over-excavation, specifically including:

[0020] If the required rock wall angle after over-excavation is less than 30°, a first anchor bolt is installed on the rock wall excavation surface, and a groove is provided at the first anchor bolt.

[0021] If the required over-excavation results in a rock wall angle greater than 30°, a second anchor bolt is installed on the rock wall excavation surface. The first anchor bolt is installed at the upper end of the rock wall excavation surface, and the second anchor bolt is installed at the lower end of the rock wall excavation surface. Both the first and second anchor bolts are provided with grooves.

[0022] In one implementation method, in step 3, the required angle of the rock wall after over-excavation is greater than 30°. After backfilling with concrete, the surface of the backfill concrete is roughened, and the concrete crane beam is poured.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This invention employs structural measures to improve the shear resistance of anchor bolts at the contact surface with surrounding rock. By applying grooves and embedded plates to the reinforcement method, the shear resistance at the contact surface with surrounding rock is increased by utilizing the connecting welds between the embedded plates and the elastic resistance at the rock wall, thereby improving the shear resistance of the anchor bolts at the contact surface with surrounding rock.

[0025] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] Figure 1 This is a rock wall crane beam rock wall over-excavation reinforcement structure according to the first embodiment of the present invention;

[0028] Figure 2 This is a rock wall crane beam rock wall over-excavation reinforcement structure according to the second embodiment of the present invention;

[0029] Figure 3 This is a partial structural diagram of the rock wall over-excavation reinforcement structure of the rock wall crane beam according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the embedded plate welding according to an embodiment of the present invention.

[0031] Among them, 1-anchor bolt, 101-first anchor bolt, 102-second anchor bolt, 2-groove, 3-rock wall side embedded plate, 4-crane beam side embedded plate, 5-embedded plate anchor bar, 6-rock wall excavation face, 8-crane beam, 7-backfill concrete. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] In this invention, terms such as "vertical" and "one end" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements of this invention, and do not specifically refer to any component or element in this invention, and should not be construed as limiting this invention.

[0036] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0037] Example 1

[0038] like Figures 1-4 As shown, this embodiment provides a rock wall crane beam rock wall over-excavation reinforcement structure, including a crane beam 8 and at least one anchor rod 1 set on the rock wall excavation surface 6. A groove 2 is set at the position of the anchor rod on the rock wall excavation surface 6. A rock wall side embedded plate 3 is set in the groove 2. A crane beam side embedded plate 4 is fixed to the rock wall side embedded plate 3. The anchor rod passes through the rock wall side embedded plate 3 and the crane beam side embedded plate 4. Anchor bars 5 are welded to the crane beam side embedded plate 4. The anchor bars are anchored into the backfill concrete 7 between the crane beam 8 and the rock wall excavation surface 6.

[0039] Furthermore, the anchor bolt is fixed to the rock wall side embedded plate 3 and the crane beam side embedded plate 4.

[0040] In this embodiment, the anchor rod and the rock wall side embedded plate 3, as well as the anchor rod and the crane beam side embedded plate 4, can be welded together, or a mechanical connection similar to bolts can be used instead. A certain length of thread can be processed at the hole through which the anchor rod passes through the embedded plate. Other connection methods, such as snap-fit ​​and adhesive bonding, are also within the protection scope of this invention.

[0041] As one or more embodiments, grooves are set at the positions of anchor bolts on the rock wall excavation surface 6 according to the required angle of the rock wall formed after over-excavation;

[0042] like Figure 1 As shown, if the required over-excavation rock wall forming rock wall angle β1 is less than or equal to 30°, staged pouring is adopted. That is, in this case, the required over-excavation range is not large and the backfill concrete thickness is small. A second anchor rod 102 is set on the rock wall excavation surface 6, and a groove is set at the second anchor rod 102.

[0043] like Figure 2As shown, if the required over-excavation rock wall angle β1 is greater than 30°, integral casting is adopted. In this case, the required over-excavation range is large and the backfill concrete 7 is thick. A second anchor rod 102 and a second anchor rod 101 are set on the rock wall excavation surface 6. The first anchor rod 101 is set at the upper end of the rock wall excavation surface 6 and the lower end of the rock wall excavation surface 6. Both the second anchor rod 102 and the first anchor rod 101 are provided with grooves.

[0044] The second anchor bolt 102 is a reinforcing anchor bolt, and the first anchor bolt 101 is a rock wall crane beam anchor bolt.

[0045] like Figure 3 As shown, in this embodiment, the embedded plate anchor bar 5 is welded onto the side embedded plate 4 of the crane beam, and the anchor bar is anchored into the concrete to increase the bonding force with the concrete.

[0046] The embedded plate anchor bar 5 can be designed according to relevant concrete structure specifications, such as the Code for Design of Concrete Structures GB50010-2010 and the Code for Design of Hydraulic Concrete Structures DL / T 5057-2009.

[0047] Other arrangements of embedded plate anchor bars are also within the scope of protection of this invention.

[0048] In this embodiment, Figures 1-2 The anchor bolt arrangement and number shown are for illustrative purposes only. Other arrangements and numbers of anchor bolts are also within the scope of protection of this invention.

[0049] It should be noted that, in this embodiment, the arrangement of the grooves can be varied, such as quincunx, straight, or rectangular, depending on the position of the anchor bolt. This embodiment does not impose any specific limitations on the arrangement.

[0050] It should be noted that in this embodiment, the shape of the groove can be rectangular, trapezoidal, or other slotted forms, and this embodiment does not impose any specific limitations.

[0051] It should be noted that the groove surface can be perpendicular to the anchor rod or at a certain angle.

[0052] In this embodiment, the current design code for rock wall crane beams, "Design Code for Rock Wall Crane Beams in Underground Powerhouses" (NB / T35079-2016), specifies that the general range for the rock wall angle β, after comprehensively considering various factors, is 20° to 40°. The general range for the bottom inclination angle β0 of the beam is 30° to 45°.

[0053] Example 2

[0054] This embodiment provides a method for reinforcing over-excavated rock walls using a rock wall crane beam, including the following steps:

[0055] Step 1: Clean the rock wall excavation surface 6, and set the groove 2 on the rock wall excavation surface 6 according to the required rock wall angle β1 after over-excavation and the position of the anchor rod;

[0056] Step 2: Place the rock wall side embedded plate 3 in the groove 2, pass the anchor rod through the rock wall side embedded plate 3, and weld the anchor rod to the rock wall side embedded plate 3. Pass the anchor rod through the crane beam side embedded plate 4; weld the rock wall side embedded plate 3 to the crane beam side embedded plate 4.

[0057] Step 3: Finally, pour the backfill concrete 7 and the crane beam concrete 8.

[0058] The principle is to add a shear barrier through the weld between the embedded plates, thereby improving the shear resistance of the anchor bolt.

[0059] In step 1, grooves are set at the positions of anchor bolts on the excavation surface 6 of the rock wall according to the required rock wall angle β1 after over-excavation, including the following implementation methods:

[0060] If the required over-excavation rock wall angle β1 is less than 30°, that is, the required over-excavation range is not large and the backfill concrete 7 is thin, and the backfill concrete 7 can be poured together with the rock wall crane beam 8 after finite element analysis, it is a reinforced area.

[0061] The second anchor bolt 102 is a reinforcing anchor bolt, and the first anchor bolt 101 is a rock wall crane beam anchor bolt.

[0062] In the reinforcement scheme, the groove 2 can be omitted at the original anchor rod 101, and the groove 2 can be set only at the reinforcement anchor rod 102. The rock wall side embedded plate 3 is placed in the groove 2, the second anchor rod 102 is passed through the rock wall side embedded plate 3, and the reinforcement anchor rod 102 is welded to the rock wall side embedded plate 3. The anchor rod is passed through the crane beam side embedded plate 4; the rock wall side embedded plate 3 is welded to the crane beam side embedded plate 4; finally, the backfill concrete 7 and the crane beam 8 concrete are poured as a whole.

[0063] For areas where the required over-excavation rock wall angle β1 is greater than 30°, i.e., the over-excavation range is large, the backfill concrete 7 is thick, and the reinforcement area is where, according to finite element analysis, the backfill concrete 7 cannot be poured together with the rock wall crane beam 8.

[0064] First, backfill the rock face with concrete. At the locations of the anchor bolts on the excavated rock face, including the first anchor bolt 101 and the second anchor bolt 102, grooves 2 are set. Then, the rock face side-embedded plate 3 is placed in the grooves 2. The first anchor bolt 101 and the second anchor bolt 102 are passed through the rock face side-embedded plate 3 and welded to the rock face side-embedded plate 3. The first anchor bolt 101 or the second anchor bolt 102 is passed through the crane beam side-embedded plate 4. The rock face side-embedded plate 3 is welded to the crane beam side-embedded plate 4. Finally, backfill with concrete 7. After the backfill with concrete 7 is completed, the surface of the backfill with concrete 7 is roughened, and the concrete crane beam 8 is poured.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rock wall crane beam structure for reinforcing over-excavation of rock walls, characterized in that, The system includes a crane beam and at least one anchor rod installed on the rock wall excavation surface. A groove is provided at the location of the anchor rod on the rock wall excavation surface. A rock wall side-embedded plate is installed in the groove. A crane beam side-embedded plate is fixed to the rock wall side-embedded plate. The anchor rod passes through the rock wall side-embedded plate and the crane beam side-embedded plate. An anchor bar is welded to the crane beam side-embedded plate. The anchor bar is anchored into the backfill concrete between the crane beam and the rock wall excavation surface. Based on the required angle of the rock wall after over-excavation, grooves are set at the positions of the anchor bolts on the rock wall excavation surface. If the required rock wall angle after over-excavation is less than 30°, a first anchor bolt is installed on the rock wall excavation surface, and a groove is provided at the first anchor bolt. If the required angle of the rock wall after over-excavation is greater than 30°, a first anchor bolt and a second anchor bolt are installed on the rock wall excavation surface. The first anchor bolt is installed at the upper end of the rock wall excavation surface and the second anchor bolt is installed at the lower end of the rock wall excavation surface. Both the first and second anchor bolts are provided with grooves. The second anchor bolt is a reinforced anchor bolt, and the first anchor bolt is a rock wall crane beam anchor bolt; The anchor rod is welded to the rock wall side-embedded plate and to the crane beam side-embedded plate.

2. The rock wall crane beam rock wall over-excavation reinforcement structure as described in claim 1, characterized in that, The arrangement of the grooves depends on the location of the anchor bolts, including quincunx, straight, or rectangular arrangements.

3. The rock wall crane beam rock wall over-excavation reinforcement structure as described in claim 1, characterized in that, The anchor bolts are replaced by anchor cables or prestressed anchor bolts.

4. A method for reinforcing over-excavation rock face using a rock wall crane beam, employing a rock wall crane beam structure for over-excavation reinforcement as described in any one of claims 1-3, characterized in that... Includes the following steps: Step 1: Clean the rock wall excavation surface and, based on the angle of the rock wall formed after over-excavation, set grooves at the positions of the anchor bolts on the rock wall excavation surface; Step 2: Place the rock wall side-embedded plate in the groove, pass the anchor rod through the rock wall side-embedded plate, and weld the anchor rod to the rock wall side-embedded plate. Pass the anchor rod through the crane beam side-embedded plate, and weld the rock wall side-embedded plate to the crane beam side-embedded plate. Step 3: Finally, backfill concrete and crane beam concrete are poured.

5. The method for reinforcing over-excavation of rock face using a rock wall crane beam as described in claim 4, characterized in that, When the required over-excavation rock wall angle is greater than 30°, after backfilling with concrete, roughen the surface of the backfill concrete and continue pouring concrete crane beams.

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