JP2022110480A - Tunnel backfilling method - Google Patents

Abstract

To use more construction surplus soil to backfill tunnels and pump fluidized soil to casting sites further from a manufacturing plant.SOLUTION: In a tunnel backfilling method, fluidized soil that is pressure-fed to one placing place P1 out of a plurality of placing places is produced by kneading excavated soil, a solidifying material and water in a first composition. The fluidized soil that is pressure-fed to another placement place P2 having a longer pumping distance than one placement place P1 is produced by kneading the excavated soil, the solidification material and water in the second composition, which contains less excavated soil and more water than the first composition.SELECTED DRAWING: Figure 3

Description

The present invention relates to a tunnel backfilling method.

BACKGROUND ART In traffic tunnel construction, a part of a tunnel formed by excavating natural ground is sometimes backfilled with fluidized soil to form a roadbed. Patent Literature 1 discloses that the fluidized soil used for backfilling is produced by adding a solidifying material and water to construction-generated soil generated by excavating the natural ground of a tunnel and kneading the mixture. In the method disclosed in Patent Document 1, a manufacturing plant for kneading construction-generated soil, solidification material and water to produce fluidized soil is provided near the entrance of the tunnel, and the fluidized soil is discharged from the manufacturing plant into the tunnel. It is pumped to the casting site using a pump.

JP 2009-84940 A

In the method disclosed in US Pat. No. 5,400,000, there is a need to use more construction surplus soil for backfilling tunnels and to pump the fluidized soil to a casting site farther from the manufacturing plant. In order to increase the amount of construction-generated soil used, it is effective to reduce the amount of water per unit volume of fluidized soil and increase the amount of construction-generated soil. On the other hand, in order to extend the pumping distance of the fluidized soil, it is effective to reduce the amount of construction-generated soil per unit volume of the fluidized soil, increase the amount of water, and improve fluidity. At present, the amount of construction-generated soil and the amount of water per unit volume of the fluidized soil are determined so that the fluidized soil has fluidity that can be pumped over a predetermined pumping distance. The increase in the amount of construction soil used and the extension of the pumping distance are contradictory problems.

It is an object of the present invention to use more construction surplus soil for backfilling tunnels and to pump the fluidized soil to a casting site farther from the manufacturing plant.

According to the present invention, construction-generated soil, a solidification material, and water are kneaded in a manufacturing plant to produce fluidized soil, and the fluidized soil is pumped from the manufacturing plant to each of a plurality of placement locations in the tunnel. A tunnel backfilling method for backfilling, wherein the fluidized soil that is pressure-fed to one of a plurality of placement sites is produced by kneading construction-generated soil, solidification material, and water in a predetermined composition. Then, the fluidized soil that is pumped to another placement location with a longer pumping distance than the one placement location is constructed with a different mixture that has less soil generated from construction and more water than the predetermined composition. Manufactured by kneading generated soil, solidifying material and water.

According to the present invention, more construction surplus soil can be used to backfill tunnels, and the fluidized soil can be pumped to casting sites further away from the manufacturing plant.

It is a figure for demonstrating the outline of the tunnel backfilling method based on this embodiment of this invention. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG. 1; FIG. 3 is a diagram for explaining the tunnel backfilling method according to the present embodiment of the present invention, where (a) shows a state in which a tunnel has been excavated to a certain point, and (b) is shown in FIG. 3(a). It shows a state in which the tunnel is further excavated from the state. FIG. 5 is a diagram for explaining a tunnel backfilling method according to a modification of the present embodiment of the present invention; b) shows a state in which the tunnel is further backfilled from the state shown in FIG. 4(a).

Hereinafter, a tunnel refilling method according to an embodiment of the present invention will be described with reference to the drawings. Here, a case of backfilling a tunnel constructed by the shield construction method to form a road in the tunnel will be described.

FIG. 1 is a diagram for explaining the outline of the tunnel refilling method according to this embodiment, and FIG. 2 is a cross-sectional view taken along line II-II shown in FIG.

As shown in FIG. 1, the tunnel T is constructed using a shield machine 10 in this embodiment. A shield excavator 10 includes a hollow body 11 capable of supporting the inner wall of natural ground, and a cutter 12 rotatably mounted on the body 11. - 特許庁Inside the fuselage 11, the segment rings 20 are sequentially constructed as the shield machine 10 advances. The segmented ring 20 is constructed by assembling a plurality of preformed segments 21 into an annular shape. The segment 21 before assembly is transported using a carriage 22 arranged behind the shield machine 10 .

A jack (not shown) is fixed to the body 11 . The jack obtains a reaction force from the segment ring 20 to propel the body 11 in the axial direction of the tunnel T, and axially press the cutter 12 against the ground. When the body 11 is propelled and the segment ring 20 comes out of the body 11, a back-filling material (not shown) is filled between the outer peripheral surface of the segment ring 20 and the inner wall of the ground.

The cutter 12 is rotated with respect to the body 11 by being driven by a motor (not shown) provided inside the body 11 . The cutter 12 is provided with a plurality of cutter bits 12a protruding in the axial direction of the tunnel T. As shown in FIG. When the cutter 12 rotates while being pressed against the ground, the ground is excavated in the axial direction by the cutter bit 12a. Excavated soil (construction-generated soil) generated by excavating the ground is discharged from the body 11 using a screw conveyor (not shown) provided inside the body 11, and is further discharged to the ground through the tunnel T and the starting shaft H1 (not shown). It is carried out using a conveying means.

In the segment ring 20, frames 30 that define evacuation passages 31 (see FIG. 2) extending in the axial direction of the tunnel T are sequentially installed as the tunnel T is excavated. The frame 30 is, for example, a precast concrete block. Rails 32 are sequentially laid on the installed frame 30 , and a transport vehicle 33 runs on the rails 32 . The frame 30 and rails 32 before installation are mounted on a transport vehicle 33 and transported. The transport vehicle 33 may transport the unassembled segment 21 from the starting shaft H1 to the truck 22 .

As shown in FIG. 2, soil material, for example, fluidized soil, is placed beside the frame 30 when viewed in the axial direction of the tunnel T to form a roadbed 40 . The tunnel backfilling method according to the present embodiment is used to form a backfilling roadbed 40 with fluidized treated soil in the space beside the frame 30 .

Although not shown in the drawings, after the subgrade 40 is formed, crushed stones are laid evenly on the frame 30 and the subgrade 40 to form a roadbed, and asphalt-concrete is spread on the roadbed to form a road. A surface layer is formed.

As shown in FIG. 1, the fluidized soil is manufactured in a manufacturing plant 50 provided in the vicinity of the starting shaft H1. The manufacturing plant 50 kneads the excavated soil generated by excavating the tunnel T, solidifying material, water, setting retarder, fly ash, and bentonite to manufacture fluidized soil. The solidifying material is a substance that causes a hydration reaction upon contact with water, such as cement. A setting retarder is a substance that delays the hydration reaction between the solidifying material and water, and is, for example, a drug containing oxycarboxylate as a main component.

In FIG. 1, illustration of the detailed structure of the manufacturing plant 50 is omitted. Briefly describing the method of manufacturing the fluidized soil in the manufacturing plant 50, first, the excavated soil carried out from the tunnel T is stored in a pit. The excavated soil stored in the pit is put into a lump crusher, crushed, put into a mixer together with quicklime, mixed and agitated. Quicklime reduces the moisture content in the excavated soil and modifies the excavated soil. The modified excavated soil is pulverized (for example, grain size 20 mm or less) and kept in a raw material yard for a predetermined period (for example, one day or longer). After that, the excavated soil is put into a kneader together with a solidification agent, water, a setting retarder, fly ash and bentonite, and kneaded. As described above, fluidized soil is produced.

A manufacturing plant 50 is provided with a pump 51, and a pumping pipe 52 is laid in the tunnel T from the pump 51 through the starting shaft H1. The fluidized soil manufactured in the manufacturing plant 50 is pressure-fed from the pump 51 through the pressure-feeding pipe 52 to a placement location in the tunnel T and placed.

FIG. 3 is a diagram for explaining the tunnel backfilling method according to this embodiment. FIG. 3(a) shows a state in which the tunnel T has been dug up to a certain point, and FIG. 3(b) shows a state in which the tunnel T has been further dug from the state shown in FIG. 3(a).

As shown in FIG. 3( a ), when backfilling the tunnel T, first, a barrier plate 41 is installed with a gap in the axial direction of the tunnel T from the roadbed 40 (fluidized soil that has been placed). to demarcate the casting place P1. In addition, the pressure-feeding pipe 52 is laid so that the outflow port 52a of the pressure-feeding pipe 52 is positioned above the placing place P1. Next, the fluidized soil manufactured in the manufacturing plant 50 (see FIG. 1) is pumped and poured from the pumping pipe 52 into the placement site P1. As a result, the placing place P1 is backfilled to form a subgrade 40 (see FIG. 3(b)).

The backfilling of the placement site P1 is performed in parallel with the excavation of the tunnel T and the installation of the frame 30 .

After the fluidized soil that has been placed in the placing place P1 is solidified, as shown in FIG. 3(b), the barrier plate 41 is moved toward the shield machine 10 to newly define the placing place P2. do. Further, a new pressure-feeding pipe 52 is added to the pressure-feeding pipe 52 that has already been laid, and the outflow port 52a of the pressure-feeding pipe 52 is arranged above the placing place P2. Next, the fluidized soil manufactured in the manufacturing plant 50 (see FIG. 1) is pumped and poured from the pumping pipe 52 into the placement site P2. As a result, the placing place P2 is backfilled to form the subgrade 40 .

In this way, the fluidized soil is pumped from the manufacturing plant 50 to each of the placement locations P1 and P2 in the tunnel T, and the tunnel T is backfilled. By repeating the determination of the placement location and backfilling in parallel with the excavation of the tunnel T and the installation of the frame 30, the space beside the frame 30 is backfilled over the entire length of the tunnel T, and the roadbed 40 is formed. It is formed.

In FIGS. 3(a) and 3(b), the site for placement is defined by the dam plate 41 and the subgrade 40 (fluidized treated soil that has been placed). may be axially spaced from each other to define the casting locations.

In such backfilling, it is required to use more excavated soil and to pump the fluidized soil to a placement site further away from the manufacturing plant 50 .

In order to increase the amount of excavated soil used, it is effective to reduce the amount of water per unit volume of fluidized soil and increase the amount of excavated soil. On the other hand, when the amount of water per unit volume of the fluidized soil is reduced, the fluidity of the fluidized soil decreases. As a result, it becomes difficult to pump the fluidized soil to casting sites further away from the manufacturing plant 50 .

For example, in the example shown in FIG. 3, in order to maximize the amount of excavated soil used for backfilling the casting site P1, the fluidity must be sufficient to pump the distance from the manufacturing plant 50 to the casting site P1. It is conceivable to reduce the amount of water per unit volume of the fluidized soil as much as possible as the fluidized soil has.

On the other hand, the placing place P2 is farther from the manufacturing plant 50 along the pumping route than the placing place P1, and has a longer pumping distance than the placing place P1 due to the spliced pumping pipe 52. - 特許庁Therefore, when the fluidized soil that is pumped to the placing place P2 is produced with the same composition as the fluidized soil that reduces the amount of water to the maximum so that it can be pumped to the placing place P1, It becomes difficult to pump the fluidized soil to the location P2.

When the fluidized soil having the fluidity that can be pumped to the placing place P2 is pumped to the placing place P1 and backfilled, the amount of water per unit volume of the fluidized soil becomes more than necessary. As a result, the amount of excavated soil used for backfilling the placement site P1 cannot be maximized.

Therefore, in the present embodiment, in the backfilling of the placing places P1 and P2 shown in FIG. are produced in different formulations. Specifically, the fluidized soil to be pumped to the placing place P1 is manufactured with the first composition shown in Table 1, and the fluidized soil to be pumped to the placing place P2 is manufactured with the second composition shown in Table 1. manufacture.

Table 1 shows the amount of excavated soil, solidifying agent, water, setting retarder, fly ash and bentonite in the fluidized soil, in terms of the amount per unit volume of the fluidized soil, that is, the blending amount. The solidification material is mainly a cement-based solidification material, including a lime-based solidification material. A setting retarder has the effect of delaying the setting of a cement-based solidifying material or a lime-based solidifying material. Fly ash and bentonite are used as at least two types of powder, and these powders have a smaller particle size distribution than the excavated soil, and compensate for the fine particles in the particle size distribution of the excavated soil. . By supplementing the fine particles of the excavated soil, the water retention capacity of the fluidized soil is improved and the fluidity is improved. Comparing fly ash, which is the first powder, and bentonite, which is the second powder, of the two types of powder, fly ash also has a solidifying effect. The first powder can be replaced with fly ash and slag fine powder or the like, and the second powder can be replaced with bentonite and clay sand or the like.

In Table 1, the excavated soil volume S2 is less than the excavated soil volume S1, and the water volume W2 is greater than the water volume W1. That is, the second mix contains less excavated soil and more water than the first mix. Therefore, the amount of excavated soil used in the fluidized soil pumped to the placement site P1 is greater than in the case of producing the fluidized soil with the second blending. In addition, the fluidity of the fluidized soil pumped to the placement site P2 is higher than in the case of producing the fluidized soil with the first blending. Therefore, the amount of excavated soil used for backfilling the placement site P1 can be increased, and the fluidized soil can be pumped to the placement site P2 which is further away from the manufacturing plant 50 .

Although illustration and display are omitted, the fluidized soil that is pressure-fed to a placement site closer to the manufacturing plant 50 than the placement site P1 is produced with a formulation containing more excavated soil and less water than the first formulation. . The fluidized soil that is pumped to a placement location farther from the manufacturing plant 50 than the placement location P2 is produced with a formulation containing less excavated soil and more water than the second formulation. As a result, more excavated soil can be used for backfilling the tunnel T, and the fluidized soil can be pumped to a placement site farther from the manufacturing plant 50 .

As previously mentioned, casting location P2 has a longer pumping distance than casting location P1. In other words, the fluidized soil pressure-fed to the placing place P2 flows through the pumping pipe 52 for a longer time than the fluidized soil pressure-fed to the placing place P1. Therefore, there is a risk that the fluidized soil will solidify within the pressure feed pipe 52 .

Therefore, in the present embodiment, as shown in Table 1, the setting retarder amount R2 is made larger than the setting retarder amount R1. That is, the second formulation contains more setting retarder than the first formulation. Therefore, the hydration reaction in the fluidized soil pressure-fed to the placement site P2 is delayed as compared with the fluidized soil pressure-fed to the placement site P1. Therefore, it is possible to prevent the fluidized soil from solidifying inside the pumping pipe 52 before it is pumped to the placement site P2.

Although illustration and display are omitted, the fluidized soil that is pressure-fed to a placement site closer to the manufacturing plant 50 than the placement site P1 is produced with a formulation containing less setting retardant than the first formulation. The fluidized soil that is pumped to a placement location farther from the manufacturing plant 50 than the placement location P2 is produced with a formulation that contains more setting retardant than the second formulation. As a result, even when the fluidized soil is pumped to a placement site farther from the manufacturing plant 50, it is possible to prevent the fluidized soil from solidifying during pumping.

The solidifying material amount C2, the fly ash amount F2, and the bentonite amount B2 may be substantially the same as or different from the solidifying material amount C1, the fly ash amount F1, and the bentonite amount B1, respectively.

The amount of solidified material C2, the amount of fly ash F2, and the amount of bentonite B2 may be changed for each placement location, more specifically, according to the strength of the fluidized soil placed at the placement location P1. good. Specifically, the strength of the fluidized soil placed at the placement location P1 is measured, and when the measured strength is higher than a predetermined threshold value, the soil is placed at the placement location P2. The amount of solidified material C2 or the amount of fly ash (first powder) F2 is reduced so that the strength of the fluidized soil is reduced, and the amount of bentonite (second powder) B2 is increased accordingly. and if the measured strength is lower than a predetermined threshold, the amount of solidified material C2 or fly ash The (first powder) amount F2 may be increased and the bentonite (second powder) amount B2 may be reduced accordingly. In addition, since the solidification material amount C2 has the greatest impact on the strength of the fluidized soil after hardening, if possible, the strength should be finely adjusted by varying the powder amount (fly ash amount F2 and bentonite amount B2). is preferred.

According to the above embodiment, the following operational effects are obtained.

In the tunnel backfilling method according to the present embodiment, the fluidized soil that is pressure-fed to the placement site P1 is produced by kneading the excavated soil, the solidification material, and water in the first mixture, and is pressure-fed to the placement site P2. The fluidized soil is produced by kneading the excavated soil, the solidifying material and water in the second composition, which contains less excavated soil and more water than the first composition. Therefore, the amount of excavated soil used in the fluidized soil pumped to the placement site P1 is greater than in the case of producing the fluidized soil with the second blending. In addition, the fluidity of the fluidized soil pumped to the placement site P2 is higher than in the case of producing the fluidized soil with the first blending. Therefore, the amount of excavated soil used for backfilling the placement site P1 can be increased, and the fluidized soil can be pumped to the placement site P2 which is further away from the manufacturing plant 50 .

This embodiment is more effective when the total length of the tunnel T is long (for example, 4 km or more) or when constructing two tunnels T by reciprocating the shield machine 10 .

The first formulation contains a predetermined amount of setting retarder per unit volume of the fluidized soil, and the second formulation contains more setting retarder than the first formulation. Therefore, the hydration reaction in the fluidized soil pressure-fed to the placement site P2 is delayed as compared with the fluidized soil pressure-fed to the placement site P1. Therefore, it is possible to prevent the fluidized soil from solidifying inside the pumping pipe 52 before it is pumped to the placement site P2.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

In the above embodiment, in parallel with the excavation of the tunnel T, the production of the fluidized treated soil that is pressure-fed to the placement site P1 and the production of the fluidized treated soil that is pressure-fed to the placement site P2 are sequentially performed. However, the present invention is not limited to this form. The tunnel T may be backfilled after the excavation of the tunnel T is completed. In this case, the tunnel T may be backfilled in order from near the manufacturing plant 50, or may be backfilled in order from far from the manufacturing plant 50 as shown in FIG.

FIG. 4 is a diagram for explaining a tunnel backfilling method according to a modification of this embodiment. FIG. 4(a) shows a state in which a roadbed 40 is formed by backfilling the tunnel T from the arrival pit H2 toward the departure pit H1 after the excavation of the tunnel T is completed. FIG. 4(b) shows a state in which the tunnel T is further backfilled from the state shown in FIG. 4(a).

As shown in FIG. 4( a ), a barrier board 41 is installed with a gap in the axial direction of the tunnel T from the roadbed 40 (fluidized treated soil that has been placed) to define the placing place P2. Also, the pressure-feeding pipe 52 is laid so that the outflow port 52a of the pressure-feeding pipe 52 is positioned above the placing place P2. Next, in the manufacturing plant 50, fluidized soil is manufactured with a second blend and pumped. As a result, the placing place P2 is backfilled to form a subgrade 40 (see FIG. 4(b)).

After the fluidized soil placed in the placing place P2 is solidified, as shown in FIG. 4(b), the barrier plate 41 is moved toward the starting shaft H1 to newly define the placing place P1. . Also, a portion of the pressure-feeding pipe 52 that has already been laid is removed, and the outflow port 52a of the pressure-feeding pipe 52 is provided above the placing place P1. Next, in the manufacturing plant 50, fluidized soil is manufactured with the first mixing and pumped. As a result, the placing place P1 is backfilled to form the subgrade 40 .

Also by this procedure, the fluidized soil to be pumped to the placing place P1 is produced with the first mixing ratio, and the fluidized soil to be pumped to the placing place P2 has less excavated soil and water than the first mixing ratio. Since it is manufactured with the second formulation with a large amount of , the amount of excavated soil used for backfilling the placing place P1 can be increased, and the fluidized soil can be transferred to the placing place P2, which is further away from the manufacturing plant 50. can be pumped.

In the example shown in FIG. 4, the manufacturing plant 50 is provided near the departure shaft H1, but the manufacturing plant 50 may be provided near the arrival shaft H2.

As in the above embodiment, in parallel with the excavation of the tunnel T, the production of the fluidized treated soil to be pressure-fed to the placement site P1 and the production of the fluidized treated soil to be pressure-fed to the placement site P2 are sequentially performed. In some cases, the tunnel T is backfilled in parallel with the excavation of the tunnel T. Therefore, the time required for excavating the tunnel T and backfilling the tunnel T can be shortened.

In the above embodiment, the excavated soil generated by excavating the tunnel T is used to manufacture the fluidized soil. It may be used to produce fluidized soil.

As in the above embodiment, when the excavated soil generated by excavating the tunnel T is used to manufacture the fluidized soil, the disposal amount of the excavated soil can be reduced, and the cost required for disposal can be reduced. can be done. Therefore, construction costs for the tunnel T can be reduced. In addition, since the disposal amount of excavated soil is reduced, the environmental load can be reduced.

In the above embodiment, the case of forming the roadbed 40 in the tunnel T has been described, but the present invention is applied to the case of backfilling the tunnel T for a purpose different from the formation of the roadbed 40 (for example, the purpose of blocking the tunnel T). may be used for

In the above embodiment, the case of backfilling the tunnel T constructed by the shield construction method is described, but the present invention is also applicable to backfilling of tunnels constructed by construction methods different from the shield construction method.

In the above embodiment, fly ash and bentonite are kneaded together with excavated soil, solidification material, water and setting retarder to produce fluidized soil, but fly ash and bentonite may be omitted. In the above embodiment, the set retarder is kneaded together with the excavated soil, solidifying material and water to produce the fluidized soil, but the set retarder may be omitted.

50... Manufacturing plant T... Tunnels P1, P2... Place of casting

Claims (4)

In a manufacturing plant, soil generated from construction, a solidification material, and water are kneaded to produce fluidized soil, and the fluidized soil is pumped from the manufacturing plant to each of a plurality of placement locations in a tunnel to complete the tunnel. A tunnel backfilling method for backfilling,
The fluidized soil to be pumped to one of a plurality of placement sites is produced by kneading the construction-generated soil, the solidification material, and the water in a predetermined composition,
The fluidized soil that is pumped to another placement location having a longer pumping distance than the one placement location is different from the one that contains less construction-generated soil and more water than the predetermined mix. Manufactured by kneading the construction-generated soil, the solidifying material and the water in a formulation,
Tunnel backfill method. The predetermined formulation contains a set retardant in a predetermined amount per unit volume of the fluidized soil,
the other formulation has more of the setting retarder than the predetermined formulation;
The tunnel backfilling method according to claim 1. In parallel with the excavation of the tunnel, the production of the fluidized soil to be pumped to the one placing place and the production of the fluidized soil to be pumped to the other placing place are sequentially performed.
The tunnel backfilling method according to claim 1 or 2. The construction-generated soil includes excavated soil generated by excavating the tunnel.
The tunnel backfilling method according to any one of claims 1 to 3.

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