JP4122595B2 - Internal water pressure compatible segment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a segment used for lining a shield tunnel, and more particularly to a segment used for lining a shield tunnel to which internal water pressure is applied.
[0002]
[Prior art]
Conventionally, a general shield tunnel is referred to as a shield machine, and a cylinder that performs excavation by a cutter head provided at the front end of the excavator while obtaining a propulsion reaction force by pressing the spreader provided at the rear part of the excavator against the segment. In order to support the tunnel ground, a block segment (eg steel) is connected along the tunnel ground surface at the rear of the shield machine. Tunnel primary lining was performed, and unshielded concrete was placed on the inner periphery of the primary lining as a secondary lining to form a shield tunnel.
[0003]
Especially in shield tunnels formed for the purpose of water transfer, the tunnel is filled with water and the internal water pressure is loaded, so correspondingly, the height of the primary lining segment is increased. By increasing the rigidity and strengthening the connection structure between the segments, the structural strength of the entire segment responsible for the primary lining can be increased, or reinforced concrete can be placed in the secondary lining instead of unreinforced. In some cases, measures were taken to improve the strength of the next lining.
[0004]
[Problems to be solved by the invention]
However, with respect to the internal water pressure generated in the shield tunnel, the segment unit price increases according to conventional measures such as increasing the digit height of the segments to improve the rigidity or strengthening the connection structure between the segments. As a result, the cost per unit increases and the weight per segment increases, so it becomes necessary to increase the capacity and the number of various devices required for transportation and connection installation. There is a risk that the tunnel will become thicker and the volume inside the tunnel will decrease.
[0005]
Furthermore, if the conventional connection structure between segments is strengthened, there is a risk that the structure will be complicated and the construction efficiency will be reduced.
[0006]
In other words, based on the idea of improving the segment strength against the internal water pressure, it would be unnecessarily repeated to take a so-called rear-end measure such as increasing the thickness of the component according to the water pressure. is there.
[0007]
Therefore, even if any of the above countermeasures is taken, it is likely that a significant decrease in both economic efficiency and workability is observed.
[0008]
Therefore, the present invention has been made paying attention to such a conventional problem, has a simple structure, is easy to transport and install, and can be easily covered regardless of the internal water pressure in the shield tunnel. It is possible to provide an internal water pressure compatible segment that can maintain the structural strength and exhibits good workability and economy.
[0009]
[Means for Solving the Problems]
The present invention has been made in order to achieve the above object, and is an internal water pressure compatible segment responsible for lining a shield tunnel in which water pressure is loaded from the inside of the tunnel, and is outside the segment abutting against the tunnel ground. The surface is provided with a reservoir layer made of a porous material and capable of permeating and aquiring water. The reservoir layer and the inner surface of the segment facing the inner side of the tunnel are passed through and connected to each other. It is characterized in that a water passage hole for performing water is provided.
[0010]
Further, the present invention is characterized in that a check valve for suppressing the inflow of water from the tunnel ground side to the tunnel interior side is provided in the water passage hole of the internal water pressure compatible segment.
[0011]
Furthermore, the outer surface of the reservoir layer is provided with a coating layer that suppresses the inflow of earth and sand from the tunnel ground or the backfill material injected between the tunnel ground and the segment. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
FIG. 1 is an explanatory diagram showing an example in which the internal water pressure compatible segment of the present invention is used in a shield tunnel 10 that extends from an upstream portion of a waterfall F to a power generation facility E downstream of the waterfall F.
[0014]
When constructing the shield tunnel 10 using the internal water pressure-compatible segment 20 of the present invention, for example, if it is for power transmission as in this embodiment, the flowing water level and the groundwater level upstream of the waterfall F are taken into account. Then, the vertical shaft point 12 at which excavation is started is determined, and the shield machine is carried into the vertical shaft following the excavation of the vertical shaft.
[0015]
The shield excavator carried in performs excavation work with a cutter head provided at the front end of the excavator while pressing the spreader provided at the rear of the excavator against the existing segment to obtain a propulsion reaction force.
[0016]
During excavation, in order to support the tunnel ground 11, the inner water pressure corresponding segment 20 of the present invention is connected along the tunnel ground at the rear of the shield excavator to perform primary tunnel lining.
[0017]
FIG. 2 is a schematic view showing the internal water pressure-compatible segment 20. The internal water pressure-compatible segment 20 has a substantially trapezoidal shape on the outer surface of a general segment main body 20 a made of steel, for example. A reservoir 20b made of a quality material (for example, porous concrete) is provided.
[0018]
Further, a water passage hole 20c is provided through the reservoir layer 20b and the inner surface of the segment facing the inner space of the tunnel. (In the present embodiment, an example in which a tubular water pipe is further inserted into the water hole 20c is illustrated.)
As a function of the reservoir layer 20b and the water passage hole 20c, the spring water from the tunnel ground 11 and the pressure water in the shield tunnel 10 can be circulated to each other while being appropriately retained in the porous body in the reservoir layer 20b. Thus, the pressure difference between the ground water pressure and the water pressure in the shield tunnel is canceled out, and the stress acting on the segment other tunnel structure is reduced.
[0019]
FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and shows a state in which the internal water pressure corresponding segment 20 is constructed on the tunnel ground 11.
[0020]
As shown in the figure, between the surface of the tunnel ground 11 where the construction is performed and the segment 20, first, the internal water pressure responsive segment 20 of the present invention is constructed as a primary lining, and then the backfill material 30 is injected. Is done.
[0021]
This backfilling material 30 prevents the collapse of the surface of the tunnel ground 11, reliably connects the internal water pressure compatible segment 20 of the present invention and the tunnel ground 11, and has a slight water permeability. It enables mutual circulation between the spring water from the mountain 11 and the pressure water in the shield tunnel 10.
[0022]
FIG. 4 is a cross-sectional view of the internal water pressure compatible segment 20 in which a check valve 20d is provided inside the water flow hole 20c.
[0023]
The internal water pressure compatible segment 20 shown in FIG. 4 has the same basic structure as the above-mentioned segment, but a semipermeable membrane that limits the water permeation direction to one direction, for example, inside the water passage 20c. The check valve 20d configured by the above is provided, and has a function of suppressing the inflow of water from the tunnel ground 11 side.
[0024]
In addition to the above, a coating layer that suppresses the inflow of the earth and sand from the tunnel ground 11 or the backfill material 30 injected between the tunnel ground 11 and the segment 20 is provided on the outer surface of the reservoir layer 20b. The provided internal water pressure compatible segment can also be adopted.
[0025]
In relation to the above, in order to control the speed at which the pressure water in the shield tunnel 10 diffuses into the tunnel ground 11, and suppress the ground collapse and weakening due to the increase in water content, Based on this, it is necessary to take measures such as appropriately selecting and changing the porous material forming the reservoir layer 20b.
[0026]
In the present embodiment, an example in which one water passage hole is provided for one internal water pressure compatible segment has been shown, but this is not a limitation, and the number of installations may be increased according to the internal water pressure, the amount of water, etc. I can do it.
[0027]
【The invention's effect】
As described above in detail, according to the internal water pressure compatible segment of the present invention, a general tunnel segment surface is provided with a water reservoir layer, and further, the water flow is performed so as to connect the water reservoir layer and the segment inner surface. Comparing to the internal water pressure-compatible segment, it has a relatively simple structure with holes, and counteracts the internal water pressure in the shield tunnel, increasing the digit height and improving the rigidity, or connecting the segments together It is not a segment with measures such as strengthening.
[0028]
Therefore, along with the increase in digit height, the unit price of the segment will rise, leading to an increase in cost, and the weight per segment will need to increase, increasing the capacity and number of devices required for transportation and connection installation. In addition, there is no risk that the winding thickness of the primary lining will be increased and the empty volume in the tunnel will be reduced. The risk of reducing efficiency is also eliminated.
[0029]
In other words, the internal water pressure-compatible segment of the present invention is a departure from the conventional method of improving the segment strength against the internal water pressure, and the inside of the tunnel and the ground through the water holes and the reservoir layer according to the internal water pressure. It is possible to easily balance the mountain with pressure, thereby easily maintaining the strength of the lining structure, and in combination with the above effects, to achieve significant improvements in both economics and workability It is connected.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a construction example of a shield tunnel from an upstream waterfall portion to a downstream power generation facility using an internal water pressure compatible segment of the present invention.
FIG. 2 is a schematic view showing an internal water pressure compatible segment of the present invention.
FIG. 3 is a cross-sectional view taken along line AA of the internal water pressure corresponding segment of FIG. 2 and shows a state in which such a segment is constructed on a tunnel ground.
FIG. 4 is a cross-sectional view of an internal water pressure compatible segment, showing a state in which a check valve is provided inside the water passage hole.
[Explanation of symbols]
11 Tunnel Ground 20 Internal Water Pressure Compatible Segment 20b Reservoir 20c Water Flow Hole

Claims (3)

An internal water pressure compatible segment responsible for lining a shield tunnel where water pressure is applied from the inside of the tunnel, and the outer surface of the segment abutting against the tunnel ground is made of a porous material and allows water to permeate and ablate. The internal water pressure is characterized in that a water reservoir hole is provided to allow water to pass through by connecting the reservoir layer and the inner surface of the segment facing the inner space of the tunnel. Corresponding segment. 2. The internal water pressure-compatible type according to claim 1, wherein a check valve is provided in the water passage hole of the internal water pressure-compatible type segment so as to suppress the inflow of water from the tunnel ground side to the tunnel interior side. segment. The outer surface of the reservoir layer is provided with a coating layer that suppresses inflow of earth and sand from a tunnel ground or a backfill material injected between a tunnel ground and a segment. The internal water pressure compatible segment according to 1 or 2.

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