Overexcavation Reinforcement Structure and Method on the Abutment Side of an Underground Powerhouse

Abstract

The present invention discloses a structure and method for reinforcing overexcavation on the airside of an underground powerhouse, aiming to overcome the problem that overexcavation often occurs to varying degrees in the airside excavation between the low-elevation area and the high-elevation area of the underground powerhouse, which has an adverse impact on the safety and stability of the airside floor slab and the structures thereon. The reinforcement structure includes reinforcing bolts and backfill concrete. A number of rows of reinforcing bolts are arranged along the overexcavated part, and backfill concrete filled to the structural surface is provided in the overexcavated part. The method steps include: arranging a number of rows of reinforcing bolts in the overexcavated part on the airside; pouring backfill concrete in the overexcavated part to the structural surface. By providing support for the overexcavated part through the setting of reinforcing bolts and then adding distribution bars, tie bars and bonded prestressed anchor cables through backfill concrete, the present invention effectively ensures the safety and stability of the airside floor slab and the structures thereon through multiple measures.

Description

Technical Field

[0001] The present invention relates to the technical field of underground powerhouse construction, and particularly relates to a method and a reinforcement structure for reinforcing over-excavation on the airside of an underground powerhouse. Background Art

[0002] Due to layout requirements, an underground powerhouse is often divided into a main powerhouse area, an installation area, and an auxiliary powerhouse area. The excavation elevations of each area are generally different, so there will be an airside between the areas. Under the action of high in-situ stress or unfavorable geological structural planes, over-excavation often occurs to varying degrees in the airside excavation between the low-elevation area and the high-elevation area of the underground powerhouse, which has an adverse impact on the safety and stability of the airside floor and the structures thereon. Summary of the Invention

[0003] The present invention aims to overcome the problem that over-excavation often occurs to varying degrees in the airside excavation between the low-elevation area and the high-elevation area of the underground powerhouse, which has an adverse impact on the safety and stability of the airside floor and the structures thereon. The present invention provides a reinforcement structure and method for reinforcing over-excavation on the airside of an underground powerhouse to ensure the safety and stability of the airside floor and the structures thereon.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a reinforcement structure for reinforcing over-excavation on the airside of an underground powerhouse. The structure is arranged at the over-excavated part on the airside of the lower structure of the underground powerhouse. The reinforcement structure includes reinforcing bolts and backfill concrete. Several rows of reinforcing bolts are arranged along the over-excavated part, and the over-excavated part is filled with backfill concrete up to the structural surface.

[0006] Preferably, the diameter of the reinforcing bolts is the same as that of the original underground powerhouse system support bolts, and they need to be anchored into the bedrock by no less than 4 m. The spacing between rows and columns of the arrangement is the same as that of the original underground powerhouse system bolts, and they are arranged in a rectangular pattern.

[0007] Preferably, the reinforcing bolts need to be exposed to a thickness of one protective layer from the structural surface and bent by 15 times the diameter of the reinforcing bolts; the reinforcing bolts are inserted obliquely downward into the over-excavated part.

[0008] Preferably, distribution bars are arranged in the backfill concrete. The distribution bars are arranged in a grid pattern at the bottom and top layers of the over-excavated part, and tie bars are arranged between the two layers of distribution bars.

[0009] Preferably, a structural floor is laid above the over-excavated part in the high-elevation area. Several structural columns are arranged above the structural floor. A concealed beam is arranged in the structural floor. The cross-sectional width of the concealed beam is the same as that of the structural column, and the cross-sectional height of the concealed beam is the same as the thickness of the structural floor.

[0010] Preferably, two rows of bonded prestressed anchor cables are provided at the overexcavated part. The bonded prestressed anchor cables are arranged on both sides of the structural column and are inserted obliquely downward into the overexcavated part.

[0011] The present invention also provides a method for reinforcing and strengthening the overexcavated part on the airside of an underground powerhouse. The method includes the following steps:

[0012] Step 1, arranging several rows of reinforcing bolts at the overexcavated part on the airside;

[0013] Step 2, after the implementation of the reinforcing bolts, pouring backfill concrete at the overexcavated part to the structural surface.

[0014] Preferably, in Step 2, during the pouring process of the backfill concrete, distribution bars and tie bars are arranged in the backfill concrete.

[0015] Preferably, the method further includes: Step 3, after the pouring of the backfill concrete is completed and reaches the age requirement, arranging two rows of bonded prestressed anchor cables below the position of the structural column and below the height from its upper structural floor elevation.

[0016] Preferably, the method further includes: Step 4, adding a concealed beam at the structural floor at the position of the structural column; the cross-sectional width of the concealed beam is the same as the cross-sectional width of the structural column, and the cross-sectional height of the concealed beam is the same as the thickness of the structural floor.

[0017] Compared with the existing methods, the technical solution of the present invention provides support for the overexcavated part by setting reinforcing bolts, and then through backfill concrete, adding distribution bars, tie bars and bonded prestressed anchor cables to form multiple measures to effectively ensure the safety and stability of the airside floor and the structure above it. Description of the Drawings

[0018] Figure 1 is the plan layout drawing of a structure for reinforcing and strengthening the overexcavated part on the airside of an underground powerhouse according to the present invention.

[0019] Figure 2 is the cross-sectional view of a structure for reinforcing and strengthening the overexcavated part on the airside of an underground powerhouse according to the present invention.

[0020] Figure 3 is the longitudinal sectional view of a structure for reinforcing and strengthening the overexcavated part on the airside of an underground powerhouse according to the present invention.

[0021] In the drawings: 1, reinforcing bolt; 2, backfill concrete; 3, distribution bar; 4, tie bar; 5, bonded prestressed anchor cable; 6, structural column; 7, concealed beam; 8, structural floor; 9, airside; 10, overexcavated part; 11, high elevation area; 12, low elevation area. Detailed Embodiment

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] As Figure 1 , Figure 2 , Figure 3 shown, an overexcavation reinforcement structure on the airside of an underground powerhouse, the structure is arranged at the overexcavated part 10 on the airside 9 of the lower structure of the underground powerhouse. The characteristics are that the reinforcement structure includes reinforcement bolts 1 and backfill concrete 2. The reinforcement bolts 1 are arranged in several rows along the overexcavated part, and the backfill concrete 2 filled to the structural surface is provided in the overexcavated part.

[0024] The diameter of the reinforcement bolts 1 is the same as that of the original support bolts of the underground powerhouse system, and they need to be anchored into the bedrock by no less than 4 m. The spacing between rows and columns is the same as that of the original support bolts of the underground powerhouse system, and they are arranged in a rectangular pattern.

[0025] The reinforcement bolts 1 need to be exposed to a thickness of one protective layer from the structural surface and bent by 15 times the diameter of the reinforcement bolts 1; the reinforcement bolts 1 are inserted obliquely downward into the overexcavated part.

[0026] Distribution bars 3 are arranged in the backfill concrete 2. The distribution bars 3 are arranged in a grid pattern at the bottom and top layers of the overexcavated part. Tie bars 4 are provided between the two layers of distribution bars 3. The recommended spacing between rows and columns of the tie bars is 0.4 m × 0.4 m.

[0027] At the high elevation area, a structural floor slab 8 is laid above the overexcavated part. Several structural columns 6 are arranged above the structural floor slab 8. A concealed beam 7 is provided in the structural floor slab 8. The cross-sectional width of the concealed beam 7 is the same as the cross-sectional width of the structural column 6, and the cross-sectional height of the concealed beam 7 is the same as the thickness of the structural floor slab 8.

[0028] Two rows of bonded prestressed anchor cables 5 are provided in the overexcavated part. The bonded prestressed anchor cables 5 are arranged on both sides of the structural column 6 and are inserted obliquely downward into the overexcavated part.

[0029] This embodiment also provides an overexcavation reinforcement method for the airside of an underground powerhouse based on the above reinforcement structure. The method includes the following steps:

[0030] Step 1, arrange several rows of reinforcement bolts 1 in the overexcavated part on the airside.

[0031] Step 2, after the implementation of the reinforcement bolts 1, pour the backfill concrete 2 in the overexcavated part to the structural surface. In step 2, during the pouring process of the backfill concrete 2, distribution bars 3 and tie bars 4 are arranged in the backfill concrete 2.

[0032] Step 3: After the backfill concrete 2 is poured and reaches the age requirement, two rows of bonded prestressed anchor cables 5 are arranged below the position of the structural column 6 and below the height of the elevation of the upper structural floor slab 8.

[0033] Step 4: A concealed beam 7 is added at the structural floor slab 8 at the position of the structural column 6; the cross-sectional width of the concealed beam 7 is the same as that of the structural column 6, and the cross-sectional height of the concealed beam 7 is the same as the thickness of the structural floor slab 8.

[0034] Compared with the existing methods, the technical solution of the present invention provides support for the over-excavated part by setting up reinforcing anchors, and then through the backfill concrete, multiple measures such as adding distribution bars, tie bars and bonded prestressed anchor cables effectively ensure the safety and stability of the floor slab on the airside and the structure thereon.

Claims

1. An overexcavation reinforcement structure on the airside of an underground powerhouse. The structure is arranged at the overexcavated part on the airside of the lower structure of the underground powerhouse. It is characterized in that The reinforcement structure includes reinforcing bolts (1) and backfill concrete (2). A number of rows of reinforcing bolts (1) are arranged along the overexcavated area, and the backfill concrete (2) filled up to the structural surface is provided in the overexcavated area. The diameter of the reinforcing bolts (1) is the same as that of the support bolts in the original underground powerhouse system, and they need to be anchored into the bedrock by no less than 4 m. The layout spacing of the bolts is the same as that of the bolts in the original underground powerhouse system, and they are arranged in a rectangular pattern. The reinforcing bolts (1) need to be exposed to a thickness of one protective layer from the structural surface and bent by 15 times the diameter of the reinforcing bolts (1). The reinforcing bolts (1) are inserted obliquely downward into the overexcavated area. Distribution bars (3) are arranged in the backfill concrete (2). The distribution bars (3) are arranged in a grid pattern at the bottom and top layers of the overexcavated area, and tie bars (4) are provided between the two layers of the distribution bars (3). In the high-elevation area, a structural floor slab (8) is laid above the overexcavated area. A number of structural columns (6) are provided above the structural floor slab (8). A concealed beam (7) is provided in the structural floor slab (8). The cross-sectional width of the concealed beam (7) is the same as that of the structural column (6), and the cross-sectional height of the concealed beam (7) is the same as the thickness of the structural floor slab (8). Two rows of bonded prestressed anchor cables (5) are provided in the overexcavated area. The bonded prestressed anchor cables (5) are arranged on both sides of the structural column (6), and the bonded prestressed anchor cables (5) are inserted obliquely downward into the overexcavated area.

2. A method for reinforcing over-excavation on the airside of an underground powerhouse based on the structure described in claim 1, characterized in that The method includes the following steps: Step 1, arrange a number of rows of reinforcing bolts (1) in the overexcavated area on the free face side. Step 2, after the implementation of the reinforcing bolts (1) is completed, pour the backfill concrete (2) in the overexcavated area up to the structural surface.

3. The method for overexcavation reinforcement on the free side of the underground powerhouse according to claim 2, characterized in that, In Step 2, during the pouring process of the backfill concrete (2), distribution bars (3) and tie bars (4) are arranged in the backfill concrete (2).

4. The method for reinforcing over-excavation on the air-facing side of an underground powerhouse according to claim 2, wherein The method further includes: Step 3, after the backfill concrete (2) is poured and reaches the age requirement, arrange two rows of bonded prestressed anchor cables (5) below the position of the structural column (6) and below the elevation of its upper structural floor slab (8).

5. The method for overexcavation reinforcement on the airside of an underground powerhouse according to claim 4, characterized in that, The method further includes: Step 4, add a concealed beam (7) at the structural floor slab (8) at the position of the structural column (6). The cross-sectional width of the concealed beam (7) is the same as that of the structural column (6), and the cross-sectional height of the concealed beam (7) is the same as the thickness of the structural floor slab (8).

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