JP5670683B2 - Backfill injection system and method - Google Patents

Description

  The present invention relates to a backfill injection system and method in a shield method.

  A gap called a tail void is formed between the wall of the excavated excavation mine and the lining body behind the shield excavator during excavation. Since this tail void causes loosening and settlement of the ground, it is necessary to fill it as soon as possible after passing through the shield machine. The work of filling the tail void is generally called backfilling. This backfill injection is performed by injecting into the tail void A liquid containing a curing material, an auxiliary material, a stabilizer and the like and B liquid containing a quick setting material. The A liquid is usually prepared in a plant installed on the ground, and the A liquid whose mixing ratio has been adjusted is transported to the inside of the excavation pit by pipe transportation.

  Properties required for the backfill material consisting of A liquid and B liquid include no material separation such as breathing, excellent fluidity, filling and water tightness, no dilution in groundwater, etc. For example, the strength can be obtained early. When conditions such as soil quality and groundwater at the site change along with the excavation, it is necessary to change the composition of solution A so that the backfill material satisfies the above properties. However, even if the composition of the liquid A is changed in the plant installed on the ground, the liquid A before the change remains in the pipe connecting the ground and the excavation mine. For this reason, it takes time until the change in the composition of the liquid A is reflected in the pit, and there is a problem that sufficient response cannot be taken.

  Patent Document 1 describes a processing facility for solving the above problems. This treatment equipment includes a demudging facility that defuses excavated soil and produces muddy water for backfilling, a backfilling facility that produces a backfilling material by mixing muddy water for backfilling and hardeners such as cement, etc. These are provided in the tunnel. Patent Documents 2 to 4 disclose technologies that use excavated earth and sand as part of the backfill material.

JP 2009-1989 JP-A-6-42294 JP 2009-185466 A JP 2008-150810 A

  However, since the processing facility described in Patent Document 1 is provided in the tunnel, it is necessary to transport the powdered or granular hardened material from the outside of the tunnel to the processing facility in the tunnel. Is a big burden.

  The present invention has been made to solve such a problem, and can respond immediately depending on the situation of the site where backfilling is performed, and also has a sufficient burden on the conveyance of the material. It is an object to provide a backfill injection system and method that can be reduced.

The present invention relates to a backfill injection method in a shield method in which a backfill material is injected between an excavation mine and a lining body, and excavates a hardener-containing liquid containing at least a hardener and an auxiliary material from the outside of the excavation mine. Recycled material containing the hardener containing liquid piped into the mine of the mine, piped from outside the mine to the inside of the mine, and excavated soil extracted from the mine or part of the excavated soil generated by excavation. One of the characteristic points is that liquid A is obtained by mixing with muddy water . That is, the present invention provides the following backfill injection method and system .

(1) A backfilling injection method in a shield method in which a backfilling material is injected between an excavation mine and a lining body, and at least a hardening material-containing liquid containing a hardening material and an auxiliary material is removed from the outside of the excavation shaft. The hardened material-containing liquid transport process for transporting pipes into the mine, the hardened material-containing liquid piped from outside the mine into the mine, and the excavated soil that is part of the excavated soil generated by excavation and taken out in the mine Mixing process to obtain liquid A by mixing in the mixing tank installed in the tank, liquid A obtained in the mixing tank in the mine, and liquid B containing the quick setting agent are injected between the excavation mine and the lining body. A backfill injection method comprising: a backfill injection step.

(2) A backfill injection method in a shield method in which a backfill material is injected between an excavation mine and a lining body, and at least a hardening material-containing liquid containing a hardening material and an auxiliary material is removed from the outside of the excavation mine. A hardener-containing liquid transport process that transports pipes into the mine, a recycled mud preparation process that prepares recycled mud that is part of the excavated soil generated by excavation and contains the excavated soil taken out in the mine, and the outside of the mine A mixing process for obtaining liquid A by mixing the hardener-containing liquid transported by pipe into the mine and the recycled mud prepared in the mine in a mixing tank installed in the mine, and the liquid A obtained in the mixing tank in the mine And a backfilling injection method for injecting B liquid containing a quick setting agent between the excavation mine and the lining body.

( 3 ) A backfill injection system in a shield method for injecting a backfill material between an excavation mine and a lining body, which is installed outside the excavation mine and contains at least a hardening material and an auxiliary material. A plant for preparing the hardener-containing liquid, a pipe for transporting the hardener-containing liquid generated in the plant into the mine pipe, and a part of the excavated soil that is installed in the mine and generated by excavation and taken out in the mine and mixing means for obtaining a liquid a are mixed with at least one of recycled mud water, and a curing material containing liquid containing excavated soil and which was, is installed downhole, a tank for accommodating the liquid a, A backfill injection system comprising backfill injection means for injecting a liquid A and a liquid B containing a quick setting agent between an excavation mine and a lining body.

In the present invention, a hardener-containing liquid containing at least a hardener and an auxiliary material is transported by pipe transportation from the outside of the excavation shaft into the well. Therefore, it is not necessary to transport a large amount of the hardened material into the mine in the form of powder or particles, and the burden required for transporting the material can be sufficiently reduced. Also, the hardened material-containing liquid transported by pipe and the excavated soil that is part of excavated soil generated by excavation and taken out in the mine or recycled mud containing the excavated soil are mixed in a mixing tank installed in the mine. In order to obtain A solution, the distance between the preparation site of A solution and the backfill injection site can be sufficiently shortened. Therefore, it is possible to respond immediately according to the situation at the site. In particular, if a hardener-containing liquid containing a hardener at a high concentration is pipe transported into the pit, the hardener content of the A liquid can be set in a sufficiently wide range by adjusting the concentration at the preparation site .

The backfill injection method according to the present invention further includes a mud material-containing liquid transporting step of preparing a mud material-containing liquid containing an auxiliary agent outside the mine and pipe-transporting the liquid into the mine. You may obtain A liquid which further contains a material. The backfilling injection method according to the present invention may further include a water-stop material injection step of injecting a hardening material-containing liquid as a water-stop material between two adjacent lining bodies. Furthermore, it is preferable to perform quality control of the A liquid by adjusting the specific gravity of the A liquid in the mixing step.

  According to the present invention, it is possible to respond immediately depending on the situation of the site where backfilling is performed, and it is possible to sufficiently reduce the burden required for transporting the material.

It is a schematic block diagram which shows a shield machine. It is a schematic block diagram which shows the mode of backfilling injection work. It is a schematic block diagram which shows the backfill injection system which concerns on embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail. Here, the case where a digging mine is constructed using a mud pressure shield machine is illustrated.

(Shield machine)
A shield machine 50 shown in FIG. 1 is a mud pressure shield machine, and a face 51 is provided at the front end. A number of cutter bits 51 </ b> A are formed on the front surface of the face 51. An outer cylinder 52 is provided behind the face 51. In addition, a partition plate 53 is provided at a position separated from the face 51 inside the outer cylinder 52 and behind the face 51. A chamber 54 is formed between the face 51 and the partition plate 53. A motor 55 connected to the face 51 is attached to the center of the partition plate 53. When the motor 55 rotates, the face 51 rotates, and excavation is performed by a cutter bit 51A formed on the front surface of the face 51.

  An agitator 56 is attached to the partition plate 53, and a stirring bar 57 is attached to the front surface of the partition plate 53 and the rear surface of the face 51. During excavation, the excavated soil M accumulates in the chamber 54, and the excavated soil M is agitated by the agitator 56 and the stirring rod 57. A screw conveyor 58 communicating with the chamber 54 is attached to the partition plate 53. The excavated soil M is sent to the recycled muddy water preparation facility 5 through the screw conveyor 58.

  A shield jack 59 is attached to the inner peripheral surface of the outer cylinder 52 behind the partition plate 53. The jack rod of the shield jack 59 faces rearward, and can press the segment (covering body) S1 assembled at the rear portion of the outer cylinder 52. By pressing the segment S1 with the shield jack 59, the shield machine 50 is dug by the reaction force. A tail seal T is attached to the inner peripheral surface of the rear portion of the outer cylinder 52.

  As shown in FIG. 2, a tail void V is formed between the segment S <b> 2 behind the outer cylinder 52 and the wall surface of the excavation pit 200. In the segments S1 to S3, an inlet H for injecting the backfill material into the tail void is formed. Then, the simultaneous injection tube 9 is connected to the injection port H of the segment S2, and the backfill material U made of the A liquid and the B liquid is injected into the tail void V, and the backfill injection process is performed. The tail seal T prevents the backfill material from flowing from the tail void V between the outer cylinder 52 and the segment S1.

(Backfilling injection system)
The backfill injection system 100 shown in FIG. 3 is a system that performs a backfill injection process for filling the tail void V generated by the excavation of the shield machine 50. The backfill injection system 100 includes a backfill ground plant (plant) 1, a mud ground plant 2, a mixing tank (mixing means) 3, a liquid tank (tank) 4, a recycling mud preparation equipment 5, a water tank 6, and adjusted. B liquid tank 7, mud material liquid tank 8, simultaneous injection pipe (back filling injection means) 9 and pipes P1-P3 are provided.

  The back ground plant 1 is for preparing a hardener-containing liquid containing a hardener and an auxiliary material, and a B liquid containing a quick setting agent, and is installed on the ground (outside of the mine). The hardener-containing liquid prepared in the back ground plant 1 is piped into the excavation mine 200 by the pipe P1 and supplied to the mixing tank 3 in the mine. As the curing material, for example, a cement-based curing material, a slag / cement-based curing material, a slag / lime-based curing material, or the like is used. Moreover, bentonite, clay sand, etc. are used as auxiliary materials. Further, the B liquid prepared in the back ground plant 1 is transported by pipe P2 into the excavation mine 200 and supplied to the adjusted B liquid tank 7 in the mine. As the quick setting agent, for example, a water glass quick setting agent, an aluminum salt quick setting agent or the like is used.

  The sludge ground plant 2 is for preparing a sludge material-containing liquid using a sludge material containing auxiliary materials, and is installed on the ground (outside of the mine). The vulcanized material is used to adjust the content of the clay soil particles in the liquid A, and is bentonite, clay sand, or a powder or liquid containing these. The sludge containing liquid prepared in the sludge ground plant 2 is pipe-transported into the mine by the pipe P3 and supplied to the sludge material tank 8 in the mine. The mud material-containing liquid in the mud material liquid tank 8 is supplied to the shield machine 50 and the mixing tank 3 through a pipe.

  The recycle muddy water preparation equipment 5 is for adjusting the composition of muddy water containing excavated soil to prepare recycle muddy water, and is installed in a pit. The excavated soil is transported out of the mine and disposed of as a residual soil. However, the amount of excavated soil transported can be reduced by installing the recycle muddy water preparation facility 5 in the mine and taking out a part of the excavated soil for reuse. The extracted excavated soil is made into muddy water by the recycle muddy water preparation equipment 5 and further adjusted to a concentration to be recycle muddy water. In this embodiment, the mud pressure shield method is targeted. However, even when the mud shield method is targeted, the concentration of mud produced by excavation containing excavated soil is adjusted by the recycled mud preparation equipment 5. Can be prepared into recycled mud water.

  The recycled muddy water prepared by the recycled muddy water preparation facility 5 is supplied to the mixing tank 3 through a pipe. The water tank 6 is for storing water used for material dilution and is installed in a mine. The water in the water supply tank 6 is supplied to the mixing tank 3 and the recycle muddy water preparation equipment 5 through a pipe and used for adjusting the concentration of each liquid.

  You may enable it to supply solid excavation soil and a mud material to the mixing tank 3 in addition to the hardening material containing liquid mentioned above, a mud material containing liquid, a recycled mud water, and water. In this mixing tank 3, liquid A is prepared by mixing at least one of these excavated soil, recycled mud water, mud material, mud material-containing liquid, and water with a hardener-containing liquid. The A liquid obtained in the mixing tank 3 is supplied to the A liquid tank 4 installed in the mine through a pipe. In consideration of the mixing capacity of the mixing tank 3 and the consumption efficiency of the A liquid, the mixing tank 3 and the A liquid tank 4 can be replaced with one tank having the functions of these tanks.

  The A liquid in the A liquid tank 4 and the B liquid in the adjusted B liquid tank 7 are respectively sent to the simultaneous injection pipe 9 through the pipes, and the back filling material composed of the A liquid and the B liquid is formed by the simultaneous injection pipe 9. It is injected into the tail void. The distance between the mixing tank 3 in which the liquid A is mixed and the tail void into which the backfill material is injected depends on the size of the excavation pit 200, but is preferably within 200 m, more preferably within 100 m. preferable.

(Backfill injection method)
The backfill injection method by the backfill injection system 100 will be described with reference to FIG.

First, a hardener-containing liquid containing a hardener at a high concentration is prepared in the back ground plant 1. The mass ratio (C / W) of the curing material and water contained in the curing material-containing liquid is preferably 50 to 100%, more preferably 60 to 90%. If the C / W of the curing material-containing liquid is less than 50%, the response when a higher-concentration curing material-containing liquid is necessary on the site tends to be insufficient, while if it exceeds 100%, the curing material is contained. The fluidity of the liquid tends to be insufficient. Further, the mass of the curing material contained in the curing material-containing liquid 1 m ³ is preferably 350 to 600 kg, and more preferably 400 to 550 kg. If this value is less than 350 kg, the response when a higher concentration hardener-containing liquid is required on the site tends to be insufficient, while if it exceeds 600 kg, the fluidity of the hardener-containing liquid becomes insufficient. Cheap.

  The fluidity of the curing material-containing liquid can be confirmed by measuring the flow value. The flow value of the hardener-containing liquid is preferably 250 mm or more and more preferably 300 mm or more from the viewpoint of ease of pipe transportation. The flow value here means a value measured as follows. That is, first, a cylindrical member (with an inner diameter of 80 mm and a height of 80 mm) is set up vertically on the surface of the acrylic plate, and this cylindrical member is filled with a hardening material-containing liquid. Then, the hardening | curing material containing liquid in a cylindrical member is made to flow down on an acrylic board by pulling up a cylindrical member. After the spreading of the curing material-containing liquid has stopped, the diameters of the curing material-containing liquid spreading on the acrylic plate in two directions at right angles are measured, and the average value is taken as the flow value.

  A hardener-containing liquid containing a hardener at a high concentration is pipe-pipeed into the mine via a pipe P1 and supplied to the mixing tank 3 (hardener-containing liquid transport step). By transporting the hardened material in a liquid state and transporting it by pipe, it is possible to reduce the burden required for transporting the material as compared with the case of transporting the powdered or granular cured material by a belt conveyor or the like.

The curing material-containing liquid may further contain a foaming agent, air, a stabilizer, and / or clay soil particles in addition to the curing material and the auxiliary material. For example, by adding a foaming agent and air to the curing material-containing liquid, the fluidity of the material is increased and the specific gravity is decreased, and the pumpability is improved. When cement is used as the hardener, the cement water ratio represented by the following formula (1) may be used as an indicator of quality. In Formula (1), F represents the mass of clay soil particles (particle size of 74 μm or less) contained in the hardener-containing liquid per unit volume, C and W are cement contained in the hardener-containing liquid per unit volume, and Indicates the mass of water.
Cement water ratio (%) = (C + F) / W × 100 (1)

  The value of (C + F) / W of the curing material-containing liquid is preferably 55 to 105%, more preferably 65 to 95%. In addition, the clay soil particles contained in the hardener-containing liquid may be derived from an auxiliary material (mud material), or the clay earth particles may be separately added to the hardener-containing liquid.

  A mud material-containing liquid is prepared in the mud ground plant 2, and this mud material-containing liquid is pipe-transported into the excavation pit 200 by a pipe P2 and supplied to the mud material liquid tank 8 (mud material-containing liquid). Transport process).

  Furthermore, the recycle muddy water preparation equipment 5 prepares recycle muddy water containing excavated soil generated by excavation of the shield machine 50 (recycle muddy water preparation step).

  Next, at least one of excavated soil, recycled muddy water, vulcanized material, vulcanized material-containing liquid, and water is supplied to the mixing tank 3, and mixed with the curable material-containing liquid supplied through the pipe P1, and then the liquid A Is obtained (mixing step).

  The amount of material to be supplied to the mixing tank 3 may be determined according to the situation at the site of the excavation pit 200. For example, it is usually preferable to mix recycled mud with a hardener-containing liquid in order to effectively utilize surplus mud moisture generated on site. By using the recycled mud as part of the liquid A, it is possible to reduce the amount of excavated soil that is transported to the outside of the mine and should be discarded as industrial waste. Moreover, when raising the early intensity | strength of a backfilling material or improving water stop, it is good to raise the compounding ratio of a hardening | curing material containing liquid rather than usual. Further, when the excavation cross section of the excavation pit 200 contains a lot of gravel and a predetermined mud cannot be obtained, the mud and the mud containing liquid are mixed with the hardened material containing liquid instead of the excavated soil and the recycled mud. Good. In addition, C / W of A liquid is about 30 to 45% normally.

  Next, the A liquid and the B liquid are injected into the tail void by the simultaneous injection tube 9 (backfill injection process). A curing material-containing liquid may be injected as a water-stopping material between two adjacent segments through a pipe (not shown) branched from the pipe P1 as necessary (water-stopping material injection step). By using the curing material-containing liquid containing the curing material at a high concentration (for example, C / W = 50 to 100%) as a water-stopping material as it is, water leakage from the gaps between adjacent segments can be effectively prevented.

  As described above, in the backfilling injection method performed by the backfilling injection system 100 according to the embodiment of the present invention, the hardening material-containing liquid containing at least the hardening material and the auxiliary material is supplied from the backfill ground plant 1 through the pipe P1. Transported into the mine. Therefore, it is not necessary to transport a large amount of the hardened material into the mine in the form of powder or particles, and the burden required for transporting the material can be sufficiently reduced.

  Also, at least one of excavated soil, recycled mud, mud material, mud material-containing liquid, and water and a hardener-containing liquid are mixed in a mixing tank 3 installed in the excavation pit 200 to obtain a liquid A. Therefore, the distance between the mixing tank 3 and the backfilling injection point can be sufficiently shortened. Therefore, it is possible to respond immediately according to the situation at the site. Furthermore, since the distance between the mixing tank 3 and the backfill injection point is short, the adjusted A liquid can be sufficiently prevented from settling and separating in the pipe, and by monitoring only the specific gravity of the A liquid after the mixing process. The quality control of A liquid can be performed. Thereby, the burden which quality control requires can be reduced compared with the past which monitors both specific gravity and viscosity.

  The backfill injection system and method according to the embodiment of the present invention have been described above, but the present invention is not limited to the above embodiment. For example, in the present embodiment, the backfill injection system 100 is applied to a mud pressure type shield method, but can also be applied to a muddy type shield method.

<Preparation and Evaluation of Curing Material-Containing Liquid>
Curing material-containing liquids having the compositions shown in Tables 1 and 2 were respectively prepared, and the fluidity of the curing material-containing liquid containing the curing material at a high concentration was confirmed. Tackment (manufactured by Tac Co., Ltd.), which is a slag / cement hardener as a curing material, TAC-α (manufactured by Tac Co., Ltd.) as an auxiliary material, TAC-2 (manufactured by Tac Co., Ltd.) as a foaming agent, and stabilizer TAC-Re (manufactured by Tac Co., Ltd.) was used. In Tables 1 and 2, C represents the mass of the curing material contained in the curing material-containing liquid per unit volume; W represents the mass of water contained in the curing material-containing liquid per unit volume; A represents the unit. The volume of air contained in the hardener-containing liquid per volume (reference state) is shown: F represents the mass of clay soil particles (particle size of 74 μm or less) contained in the hardener-containing liquid per unit volume.

<Preparation and evaluation of solution A>
Recycled muddy water, a muddy material-containing liquid and water shown in Table 3 were prepared. In addition, the same TAC- (alpha) (made by Tac Co., Ltd.) as an auxiliary material was used as a mud material used for a mud material containing liquid.

(Case 1)
The hardening material containing liquid of the combination example 4 and the said recycling muddy water were mixed by the volume ratio 1: 1, and the A liquid concerning Case 1 was obtained. The clay soil particles contained in this liquid A are derived from recycled muddy water, and occupy about 90% of the total amount of auxiliary materials and clay soil particles, and about 90% of the auxiliary materials to be originally added are recycled muddy water. Can be replaced with clay soil particles obtained from The A solution excavated soil contained (water content 30%, specific gravity 2.60) is calculated to be A solution 1 m ³ per 0.111 m ^3, excavated soil to be treated as industrial waste for the amount of such an extent Can be reduced.
(Case 2)
The hardening material containing liquid of the combination example 4 and the said mud material containing liquid were mixed by the volume ratio 1: 1, and the A liquid concerning Case 2 was obtained.
(Case 3)
The hardening material containing liquid of the combination example 4, the said mud material containing liquid, and water were mixed by volume ratio 2: 1: 1, and the A liquid concerning Case 3 was obtained.

Table 4 shows the physical properties and evaluation results of the liquid A according to the above cases 1 to 3. In addition, the water glass type quick setting agent was used as B liquid, and the mixing ratio of A liquid and B liquid was 1000: 58 (volume ratio).

Table 5 shows the amount of each material used per day when the liquid A according to Case 1 was used as the backfill material. 13.0 (m ³ ) of excavated soil can be recycled per day. Moreover, since the clay soil particles obtained from this excavated soil can be used 19.1 (t) per day, the auxiliary material to be transported from the outside of the excavation mine can be reduced 19.1 (t) per day. Furthermore, since the hardened material contained in the liquid A is pipe-transported as a hardened material-containing liquid, the burden of transporting 26.4 (t) of hardened material from the outside of the excavation mine in a powdery or granular form per day is reduced. Is done.

(Case 4)
The curing material-containing liquid of Formulation Example 1 and the mud material (solid) were mixed at a volume ratio of 0.95: 0.05 to obtain Liquid A according to Case 4.
(Case 5)
The hardening material containing liquid of the mixing example 7 and water were mixed by the volume ratio 1: 1, and the A liquid which concerns on the case 5 was obtained.

Table 6 shows the physical properties of the liquid A according to the cases 4 and 5 described above.

  DESCRIPTION OF SYMBOLS 1 ... Back ground plant (plant), 3 ... Mixing tank (mixing means), 4 ... A liquid tank (tank), 9 ... Simultaneous injection pipe (backing injection means), 100 ... Backfill injection system, 200 ... Excavation Pit, P1 ... pipe, S1-S3 ... segment (lining body).

Claims (6)

A backfill injection method in a shield method in which a backfill material is injected between an excavation mine and a lining body,
A curing material-containing liquid transporting step for pipe transporting a curing material-containing liquid containing at least a curing material and an auxiliary material from the outside of the excavation shaft into the shaft;
The hardener-containing liquid piped from the outside of the mine to the inside of the mine and the excavated earth that is part of the excavated soil generated by excavation and taken out in the mine are mixed in a mixing tank installed in the mine. Mixing step for obtaining liquid A,
A backfill injection step of injecting the A liquid obtained in the mixing tank in the mine and the B liquid containing a quick setting agent between the excavation mine and the lining body;
Backfill injection method. A backfill injection method in a shield method in which a backfill material is injected between an excavation mine and a lining body,
A curing material-containing liquid transporting step for pipe transporting a curing material-containing liquid containing at least a curing material and an auxiliary material from the outside of the excavation shaft into the shaft;
Recycled mud preparation process for preparing a recycled mud containing a portion of excavated soil generated by excavation and containing the excavated soil taken out in the mine,
A mixing step of mixing the cured material-containing liquid piped from the outside of the mine into the mine and the recycled mud prepared in the mine in a mixing tank installed in the mine to obtain liquid A;
A backfill injection step of injecting the A liquid obtained in the mixing tank in the mine and the B liquid containing a quick setting agent between the excavation mine and the lining body;
Backfill injection method. A mud containing material-containing liquid containing an auxiliary agent is prepared outside the mine, further comprising a mud material containing liquid transporting step for transporting the pipe into the mine,
The backfill injection method according to claim 1 or 2, wherein the liquid A further containing the mud material is obtained in the mixing step. The backfill injection method according to any one of claims 1 to 3 , further comprising a water-stopping material injection step of injecting the curing material-containing liquid as a water-stopping material between two adjacent lining bodies. The backfill injection method according to any one of claims 1 to 4 , wherein quality control of the A liquid is performed by adjusting a specific gravity of the A liquid in the mixing step. A backfill injection system in a shield method in which a backfill material is injected between an excavation mine and a lining body,
A plant that is installed outside the excavation pit, and that prepares a hardener-containing liquid containing at least a hardener and an auxiliary material;
A pipe for pipe transporting the hardener-containing liquid generated in the plant into the excavation pit;
Mixing is installed, and at least one of recycled mud water containing excavated soil and which was taken in the a part of the excavated soil generated by drilling downhole, and the cured material containing liquid in the downhole Mixing means for obtaining A liquid,
A tank that is installed in the mine and contains the liquid A;
Backfill injection means for injecting the A liquid and the B liquid containing a quick setting agent between the excavation mine and the lining body;
With backfill injection system.

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