Hydropower engineering dam abutment slope excavation method

Abstract

The invention discloses a hydropower engineering dam abutment side slope excavation method which comprises the following steps: before excavation of a dam abutment side slope, firstly completing construction of a construction branch hole and a main traffic hole, then performing excavation construction from top to bottom in a first-stage excavation area on an original ground line by utilizing the construction branch hole and the main traffic hole, and after excavation of the first-stage excavation area is completed, arranging a protective structure; and when the dam meets the filling condition, excavation of a second-stage excavation area is conducted, a protection structure is arranged in the excavation process, and second-stage excavation materials are directly used for filling construction of the lower dam. By means of the excavation branch holes and the main traffic hole which are arranged in a layered mode, a guarantee can be provided for efficient and rapid construction of the first-stage excavation area and the second-stage excavation area. In the construction process of the second-stage excavation area, the risk that falling rocks fall into the dam filling area is effectively reduced or blocked through protection measures such as the slope ramp pioneer groove, the slag blocking platform, the reserved rock bank, the steel pipe piles and the protection bamboo clamping plates, the construction safety of the lower dam filling area is guaranteed, and the direct dam feeding rate of excavation materials is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of hydropower and water conservancy engineering, and in particular relates to a method for excavating a dam shoulder slope of a hydropower engineering project. Background Art

[0002] At present, most of my country's hydropower and water conservancy projects are concentrated in the mountainous and canyon areas of Tibet. The geological conditions in this area are complex, the construction site is tight, and the construction of river dams is mostly earth-rock dams. The slope of the dam shoulder is high and steep, and the excavation volume is large. The excavated materials are an important source of filling materials for the dam. The excavated materials are directly filled on the dam to minimize the transfer of materials, save construction time, and reduce project investment. However, the dam shoulder slope of the project is located above the dam filling area. When the dam shoulder slope excavation and dam filling are carried out simultaneously, the interference problem between the upper and lower construction is prominent, and there are major safety hazards.

[0003] To ensure construction safety, the commonly used excavation methods for the abutment slopes of hydropower projects are: the abutment slopes are excavated from top to bottom once, and the excavated materials are transported to the transfer site, and the excavated materials are mined from the transfer site during the dam filling period; or the abutment slopes are excavated from top to bottom once, and all the excavated materials are transported to the waste dump, and the dam filling materials are mined separately from the stone field and directly transported to the dam; although the above excavation methods meet the excavation requirements of the building and can ensure the construction safety during the excavation process, there are problems such as large transfer volume of excavated materials, low utilization rate, large amount of waste, high investment, and long total construction period for the project as a whole. Therefore, an excavation method with high safety, small transfer volume, high utilization rate of excavated materials and shortened construction period is needed.

[0004] The patent document with the announcement number CN107254878A discloses a method for controlling dust in the excavation of high and steep slopes of hydropower dam shoulders. It adopts reinforced gabion slag retaining walls, reserved rock sills to block slag, and slag chute shafts to discharge slag, which effectively reduces the rolling of slag along the slope and avoids the generation of a large amount of dust. However, the patent does not set up technical content for phased and zoned excavation, excavation of materials, or direct use of materials on the dam. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for excavating a dam shoulder slope of a hydropower project.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a method for excavating a hydropower project dam shoulder slope, comprising the following steps:

[0008] S1: Before excavating the dam shoulder slope, first complete the construction of the branch tunnel and the main traffic tunnel, and then use the branch tunnel and the main traffic tunnel to excavate the first phase excavation area from top to bottom on the original ground line. After the excavation of the first phase excavation area is completed, set up a protective structure;

[0009] S2: Carry out excavation of the second phase excavation area and set up protective structures during the excavation process.

[0010] Preferably, in step S1, during the excavation of the first-phase excavation area, a slag retaining platform is set up every 60m to 100m in the first-phase excavation area, and a reserved rock sill is set up on the outer edge of the slag retaining platform.

[0011] Preferably, pipe piles and protective clamping plates are arranged on the reserved rock sill, and the pipe piles are connected to the protective clamping plates.

[0012] Preferably, locking anchor piles are provided below the reserved rock sill of the slag retaining platform in the first phase excavation area.

[0013] Preferably, in step S1, during the excavation of the first-phase excavation area, a protective net is set on the slope surface of the first-phase temporary excavation slope formed in the first-phase excavation area.

[0014] Preferably, the slope ratio of the temporary slope in the first-phase excavation area may be 0.2 to 0.4.

[0015] Preferably, in the step S2 of excavating the second phase excavation area, the ramp pioneer groove is first excavated using the construction branch tunnel, and then the first excavation area is excavated toward one side of the ramp pioneer groove, and finally the second excavation area is excavated downward.

[0016] Preferably, the ramp pioneer groove is inclined on the slope surface and arranged in a zigzag shape and is connected to the layered excavation construction branch holes.

[0017] Preferably, the longitudinal slope of the ramp pioneer groove is 10% to 15%, and both ends of the ramp pioneer groove are respectively connected to excavated branch tunnels.

[0018] Preferably, after the first excavation area is completed, the pioneer groove reserved rock sill is constructed on the other side of the ramp pioneer groove, and then the second excavation area is excavated. The ramp pioneer groove and the pioneer groove reserved rock sill are excavated by layered and zoned controlled blasting.

[0019] The beneficial effects of the present invention are:

[0020] The present invention can provide a guarantee for the efficient and rapid construction of the first-phase excavation area and the second-phase excavation area through the layered excavation branch tunnels and the main traffic tunnel. During the construction of the second-phase excavation area, the risk of falling rocks falling into the dam filling area is effectively reduced or blocked through protective measures such as the ramp pioneer trough, the slag blocking platform, the reserved rock sill, the steel pipe piles, and the protective bamboo plywood, thereby ensuring the construction safety of the lower dam filling area. The present invention improves the existing hydropower project dam shoulder slope excavation method and provides a dam shoulder slope efficient excavation method in stages. The excavation method has the advantages of high safety, high utilization rate of excavated materials, small transfer volume, low investment, short total construction period, and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the excavation area of ​​the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of the excavation area of ​​the present invention;

[0023] Figure 3 It is a structural schematic diagram of the second phase excavation area of ​​the present invention;

[0024] Figure 4 It is a schematic diagram of the structure of the pioneer trough in the excavation area of ​​the present invention;

[0025] Figure 5 It is a process flow chart of the present invention;

[0026] In the figure: 1-original ground line, 2-first phase excavation area, 2-1-slag retaining platform, 3-first phase excavation slope, 4-protection net, 5-reserved rock sill, 6-pipe piles, 7-protection splints, 8-locking anchor piles, 9-second phase excavation area, 9-1-pioneer slot in excavation area, 9-2-first excavation area, 9-3-reserved rock sill in the pioneer slot, 9-4-second excavation area, 10-branch tunnel, 11-main traffic tunnel. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0028] Example:

[0029] This example takes the excavation of the right bank abutment slope of the RM project as an example. The right bank abutment slope, spillway inlet slope, and power generation water inlet slope are constructed in an integrated manner. The maximum elevation of the slope above 2907m on the dam top is 3270m. The excavation was carried out to 3070m before the project cutoff. The abutment slope below 3070m (excluding the abutment trough slope below 2907m) was excavated in stages, with an excavation volume of approximately 14.9 million m 3 , which is an important source of materials for dam filling.

[0030] like Figures 1 to 5 As shown, a method for excavating a hydropower project dam shoulder slope comprises the following steps:

[0031] S1: Before excavating the dam shoulder slope, first complete the construction of the branch tunnel 10 and the main traffic tunnel 11, and then use the branch tunnel 10 and the main traffic tunnel 11 to excavate the first-stage excavation area 2 from top to bottom on the original ground line 1. After the excavation of the first-stage excavation area 2 is completed, set up a protective structure.

[0032] S2: Excavation of the second phase excavation area 9 is carried out, and a protective structure is set up during the excavation process.

[0033] In the step S1, during the excavation of the first-phase excavation area 2, slag retaining platforms 2-1 are arranged in layers every 60 to 100 meters in the first-phase excavation area 2, and reserved rock steps 5 are arranged at the outer edge of the slag retaining platforms 2-1.

[0034] Pipe piles 6 and protective splints 7 are arranged on the reserved rock sill 5. The pipe piles 6 are made of steel pipes. The pipe piles 6 are connected with the protective splints 7 to form a rock sill upper blocking protection system, which effectively increases the protection height. The reserved rock sill 5 has a bottom width of 4 to 6 m, a top width of about 2 m, a height of 3 to 5 m, a length of 6 to 9 m, and a row spacing of 1.0 to 1.5 m.

[0035] A locking anchor pile 8 is arranged below the reserved rock sill 5 of the slag retaining platform 2 - 1 in the first-phase excavation area 2 to increase the stability of the reserved rock sill 5 .

[0036] In the step S1, during the excavation of the first-phase excavation area 2, a slag retaining platform 2-1 is layered in the first-phase excavation area 2, the slag retaining platform 2-1 is set with a width of about 30m, a reserved rock sill 5, pipe piles 6 and protective splints 7 are set on the outer side of the slag retaining platform 2-1, and a protective net 4 is set on the first-phase temporary excavation slope 3 formed in the first-phase excavation area 2.

[0037] The slope ratio of the temporary slope in the first-phase excavation area 2 is determined according to the surrounding rock conditions and may be 0.2 to 0.4.

[0038] In the step S2 for excavating the second-phase excavation area 9, the ramp pioneer trough 9-1 is first excavated using the construction branch tunnel 10, and then the first excavation area 9-2 is excavated to one side of the ramp pioneer trough 9-1, and finally the second excavation area 9-4 is excavated downward. The second-phase excavation area 9 uses the ramp pioneer trough 9-1 to turn into the excavation branch tunnel 10 and the main traffic tunnel 11 to transport the discharged materials directly to the dam for filling. The second excavation area 9-4 is constructed in the same excavation method as the upper ramp pioneer trough 9-1 and the first excavation area 9-2, and the excavated materials can be directly transported to the dam for filling.

[0039] The ramp pioneer groove 9-1 is inclined on the slope surface and arranged in a zigzag shape and is connected to the layered excavation construction branch holes 10.

[0040] The longitudinal slope of the ramp pioneer groove 9-1 is 10% to 15%, and both ends of the ramp pioneer groove 9-1 are connected to the excavated branch holes 10 respectively.

[0041] After the completion of the first excavation area 9-2, the pioneer groove reserved rock sill 9-3 is constructed on the other side of the ramp pioneer groove 9-1, and then the second excavation area 9-4 is excavated. The ramp pioneer groove 9-1 and the pioneer groove reserved rock sill 9-3 are excavated by layered and zoned controlled blasting, which can effectively reduce the falling of slag. Through the multiple effects of the excavation of the ramp pioneer groove 9-1 and the lower slag retaining platform 2-1 and the retaining facilities on the reserved rock sill 5, the falling of excavated slag is minimized to ensure the safety of the lower dam filling construction work and the safety and reliability of the protective measures.

Claims

1. A method for excavating a dam shoulder slope of a hydropower project, characterized in that: The following steps are involved: S1: Before excavating the dam shoulder slope, first complete the construction of the construction branch tunnel (10) and the main traffic tunnel (11), excavate the construction branch tunnel (10) to connect with the main traffic tunnel (11), and then use the construction branch tunnel (10) and the main traffic tunnel (11) to carry out the first-stage excavation area (2) from top to bottom on the original ground line (1). After the excavation of the first-stage excavation area (2) is completed, a protective structure is set; S2: Excavation of the second phase excavation area (9) is carried out, and protective structures are set up during the excavation process.

2. A method for excavating a dam shoulder slope of a hydropower project as claimed in claim 1, characterized in that: In the step S1, during the excavation of the first-phase excavation area (2), a slag retaining platform (2-1) is set every 60m to 100m in the first-phase excavation area (2), and a reserved rock sill (5) is set at the outer edge of the slag retaining platform (2-1).

3. A method for excavating a dam shoulder slope of a hydropower project as claimed in claim 2, characterized in that: A pipe pile (6) and a protective clamping plate (7) are arranged on the reserved rock sill (5), and the pipe pile (6) is connected to the protective clamping plate (7).

4. A method for excavating a hydropower project dam shoulder slope as claimed in claim 2, characterized in that: A locking anchor pile (8) is arranged below a reserved rock sill (5) of a slag retaining platform (2-1) in a first-phase excavation area (2).

5. A method for excavating a hydropower project dam shoulder slope as claimed in claim 1, characterized in that: In the step S1, during the excavation of the first-phase excavation area (2), a protective net (4) is set on the first-phase temporary excavation slope surface (3) formed in the first-phase excavation area (2).

6. A method for excavating a hydropower project dam shoulder slope as claimed in claim 1, characterized in that: The temporary slope ratio of the first-phase excavation area (2) may be 0.2 to 0.

4.

7. A method for excavating a hydropower project dam shoulder slope as claimed in claim 1, characterized in that: In the step S2, during the excavation of the second phase excavation area (9), the ramp pioneer groove (9-1) is first excavated using the construction branch tunnel (10), and then the first excavation area (9-2) is excavated toward one side of the ramp pioneer groove (9-1), and finally the second excavation area (9-4) is excavated downward.

8. A method for excavating a hydropower project dam shoulder slope as claimed in claim 7, characterized in that: The ramp pioneer groove (9-1) is inclined on the slope surface and arranged in a zigzag shape and is connected to the excavated branch holes (10) arranged in layers.

9. A method for excavating a hydropower project dam shoulder slope as claimed in claim 8, characterized in that: The longitudinal slope of the ramp pioneer groove (9-1) is 10% to 15%, and both ends of the ramp pioneer groove (9-1) are respectively connected to excavated branch holes (10).

10. A method for excavating a hydropower project dam shoulder slope as claimed in claim 7, characterized in that: After the first excavation area (9-2) is completed, the pioneer groove reserved rock sill (9-3) is constructed on the other side of the ramp pioneer groove (9-1), and then the second excavation area (9-4) is excavated. The ramp pioneer groove (9-1) and the pioneer groove reserved rock sill (9-3) are excavated by controlled blasting.

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