JP2002327427A - Formation method of tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of easily forming a water tunnel for connecting water reservoirs by excavating a tunnel in a state to cover a part as a tunnel opening in advance without emptying the water reservoirs. SOLUTION: A freezing means 4 is provided around a tunnel opening planned section 3 of the reservoirs 1 and 2, an area having the freezing means 4 including the tunnel opening planned section 3 is covered with a pouring water pipe 6 attached heat insulating sheet 7, water is poured in the area covered with the heat insulating sheet 7, the water poured in the area is frozen by the freezing means 4 to form ice 8 for covering the tunnel opening planned section 3, the tunnel 10 is bored from the ground, the tunnel opening planned section 3 is opened in a state covered with the ice 8, and after the tunnel 10 has been made to pass through between both water reservoirs 1 and 2, the ice 8 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a tunnel.

[0002]

In the case of a hydroelectric power plant, when there is sufficient power supply (at night, for example), a lower reservoir (regulating pond) that temporarily receives and stores water discharged from the hydroelectric power plant is used. There is a facility that pumps up the water to the upper reservoir for power generation and drops it into the lower reservoir again to generate pumped-storage power. I have to. In recent years, in hydropower facilities that use multiple power generation reservoirs, two power generation reservoirs with elevation differences are connected by tunnels, and as necessary, the lower power generation reservoirs It is being considered to pump water into a power generation reservoir and drop it again into a lower power generation reservoir so that pumped storage can be performed.

[0003] However, in order to connect the power generation reservoirs to be connected with each other by the tunnels while the hydroelectric power generation facilities are operated without emptying each of the power generation reservoirs, the reservoirs having a large depth are required. It is necessary to provide a tunnel opening near the bottom of the water (at a depth of about 50 m to 200 m) lower than a normal water intake part, and there is a problem that the construction is difficult. Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to make it possible to perform a tunnel excavation operation in a state in which a portion to be a tunnel opening is previously covered without emptying a reservoir. The purpose of the present invention is to make it easy to form a tunnel for water flow connecting the two.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and when forming a tunnel connecting a higher-order reservoir and a lower-order reservoir, a tunnel opening scheduled portion of each of the reservoirs is formed. Around the area provided with the freezing means, including the planned opening portion of the tunnel, is covered with a heat insulating sheet with a water injection pipe, and water is injected into the area covered with the heat insulating sheet, and the water is injected by the freezing means. The frozen water is frozen to form ice covering the planned tunnel opening, the tunnel is dug from the ground, and the tunnel opening is opened while being covered with the ice to penetrate the tunnel between both reservoirs. Then, the above-mentioned problem is solved by providing a method for forming a tunnel, wherein the ice is removed.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the embodiments shown in FIGS. As shown in FIG. 5, reference numerals 1 and 2 in the figure denote reservoirs for power generation having a difference in elevation, which are reservoirs used for hydroelectric power generation facilities. Then, a tunnel connecting the reservoirs 1 and 2 is formed as follows so that pumped storage power generation can be performed using the reservoirs 1 and 2. 1 to 4 show a process on one reservoir 1 side, but the same is performed on the other reservoir 2. First, FIG.
As shown in (1), a freezing means 4 composed of a freezing tube 4a is provided around a tunnel opening scheduled portion 3 in the upper reservoir 1 and the lower reservoir 2. Freezing tube 4 constituting this freezing means 4
a cools the environment around the pipe below freezing by the action of the frozen material to be fed, and is disposed, for example, in a spiral around the planned tunnel opening 3 on the ground 5 around the planned tunnel opening 3. I do. Alternatively, bowling may be performed from the ground surface side, and the freezing tube 4a may be provided in an underground portion around the planned tunnel opening 3.
Further, as will be described later, the tunnel is dug in advance to the vicinity of the planned opening portion 3 of the tunnel, and the freezing tube 4a is embedded from the excavation tip side so that the freezing means 4 is provided around the planned opening portion 3 of the tunnel. You may. And
The above-mentioned freezing means 4 is provided, and a region including the freezing means 4 including the planned tunnel opening 3 is covered from the underwater side with a heat insulating sheet 7 to which a water injection pipe 6 for water injection from the ground surface side is connected. The periphery of the sheet 7 is fixed to the ground 5.

Next, as shown in FIG. 2, water is injected from the water injection pipe 6 and the freezing means 4 is operated to freeze the water injected between the heat insulating sheet 7 and the ground 5.
Since the water injected between the heat insulating sheet 7 and the ground 5 is frozen as described above, ice is formed in a cap shape, and the ice block 8 adheres to the planned tunnel opening 3 and the ground 5 around the planned tunnel opening 3. It will be formed in a state. Then, due to the close contact of the ice blocks 8, the portion corresponding to the tunnel opening scheduled portion 3 and the ground around the portion become extremely stable. When the water is frozen by the freezing means 4, the underground portion on the ground 5 side corresponding to the heat insulating sheet 7 is also frozen, so that the frozen ground 9 is formed. Thus, the portion corresponding to the tunnel opening scheduled portion 3 and the ground around the portion become more stable. As described above, even when the freezing means 4 is bowled and the freezing tube 4a is provided, or when the freezing tube 4a is provided from the excavation tip side of the tunnel prior to the excavation, the freezing tube 4a is formed. An ice block 8 is formed between the ground and the ground 5 so as to closely adhere to the ground 5, and a frozen ground 9 is also formed. Further, in order to increase the strength of the ice block 8, the water to be injected may contain sand or bentonite.

Next, as shown in FIG. 3, a tunnel 10 is dug from between the reservoir 1 and the reservoir 2 to the ice block 8 in each of the reservoir 1 and the reservoir 2, and the position of the tunnel opening scheduled portion 3 is determined. Is opened, and a tunnel 10 is formed to penetrate between the reservoir 1 and the reservoir 2. And
After installing pumped-storage power generation equipment 11 such as a turbine at a required position in the course of the tunnel 10, the tunnel 10
The water from the reservoir 1 is introduced into the water. When introducing water into the tunnel 10, the water injection pipe 6 and the heat insulating sheet 7 may be removed to remove the ice blocks 8.
The removal of the water injection pipe 6, the insulation sheet 7, and the removal of the ice blocks 8 are shown on the reservoir 1 side in the figure.
2 is performed. In the case where the freezing tube 4a is arranged on the surface side of the ground 5 in the freezing means 4, the freezing tube 4a may be removed after, for example, introducing water, and as shown in FIG. Tunnel opening 12 which has been subjected to hole processing by removing the freezing tube 4a
Can be formed. Further, when the freezing pipe 4a is arranged by bowling or is arranged from the excavation tip of the preceding tunnel, the frozen pipe 4a may be left buried. In the figure, 1
Reference numeral 3 denotes a working shaft.

[0008]

According to the present invention described above, in forming a tunnel connecting the upper reservoir and the lower reservoir, a freezing means is provided around the planned tunnel opening portion in each of the reservoirs, The area provided with the freezing means including the planned opening portion of the tunnel is covered with a heat insulating sheet provided with a water injection pipe, water is injected into the area covered with the heat insulating sheet, and the water injected by the freezing means is frozen to freeze the tunnel. Ice is formed to cover the opening to be opened, a tunnel is dug from underground, the tunnel opening is opened in a state of being covered with the ice, the tunnel is penetrated between both reservoirs, and the ice is removed. It is characterized by the following. In this way, the tunnel opening planned portion is covered with ice beforehand, and then the tunnel is dug from underground to reach the tunnel opening planned portion, the tunnel opening planned portion is opened, and then the ice is removed. Therefore, it is possible to penetrate the tunnel even at a deep water position without emptying the reservoir. For example, even in a reservoir such as a hydroelectric power station, it is not necessary to stop power generation. In addition, since the end of the tunnel is not opened toward the water in the reservoir until the final stage of the tunnel formation, the present invention has excellent practical effects, such as a significant reduction in the cost of stopping water.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a freezing means and a heat insulating sheet in an example of a method for forming a pumped storage power generation tunnel according to the present invention.

FIG. 2 is an explanatory diagram showing the formation of ice blocks in an example.

FIG. 3 is an explanatory view showing penetration of a tunnel in one example.

FIG. 4 is an explanatory diagram showing introduction of water into a tunnel in one example.

FIG. 5 is an explanatory diagram showing a hydroelectric power generation facility provided with a reservoir and a pumped-storage power generation function.

[Explanation of symbols]

 1, 2 ... Reservoir 3 ... Tunnel opening planned part 4 ... Freezing means 4a ... Freezing pipe 5 ... Ground 6 ... Water injection pipe 7 ... Insulating sheet 8 ... Ice block 9 ... Freezing ground 10 ... Tunnel 11 ... Pumping power generator 12 ... Tunnel opening

Claims (1)

[Claims] In forming a tunnel connecting an upper reservoir and a lower reservoir, a freezing means is provided around a planned tunnel opening in each of the reservoirs, and the freezing means including the planned tunnel opening is provided. The area provided with the means is covered with a heat insulating sheet with a water injection pipe, water is injected into the area covered with the heat insulating sheet, and the water injected by the freezing means is frozen to form ice covering the planned tunnel opening portion. Digging a tunnel from underground, opening a tunnel opening portion in a state of being covered with the ice, penetrating the tunnel between both reservoirs, and removing the ice, wherein the ice is removed. .