JP6632018B1 - Tunnel waterproofing method, tunnel waterproofing system, and waterproofing material - Google Patents

Abstract

A tunnel water stopping method for easily and reliably shutting off groundwater from the surrounding ground for a shield machine is provided. A tunnel water stopping method for blocking groundwater from the surrounding ground for a shield machine 1A that excavates a ground and constructs a tunnel, wherein the shield machine is stopped while the shield machine 1A stops excavating. A tunnel water stopping construction method including a water stopping material filling step of filling a water stopping material 15 that can be re-excavated by a shield machine 1A even when hardened, in a gap between a body 2 of the machine 1A and a surrounding ground. [Selection diagram] Fig. 1

Description

  The present invention relates to a tunnel water stopping method, a tunnel water stopping system, a water stopping material, and a grout material for cutting off groundwater from the surrounding ground for a shield machine that excavates a ground to construct a tunnel.

  When constructing a tunnel underground, for example, a closed shield machine is used. Typical examples of the shield machine include a muddy shield machine and a mud pressure shield machine. The muddy shield excavator performs excavation while applying mud pressure to the excavated surface (face) in the excavation direction while stabilizing the face. On the other hand, the shield excavator of the mud pressure type excavates excavated earth and sand, and excavates while applying a predetermined pressure (mud pressure) to stabilize the face.

  The shield machine described above includes a cylindrical fuselage, and a cutter head supported on a front portion of the fuselage so as to face the face, and is configured so that the face can be excavated by rotation of the cutter head. ing. In a shield machine, a partition is provided behind the cutter head so as to partition the body forward and backward, and a chamber is defined between the partition and the cutter head. The chamber is capable of containing muddy water or mud and serves to prevent collapse of the face against mud pressure of the face by mud pressure or mud pressure. In addition, inside the fuselage of the shield machine, a shield jack for excavation, a segment elector for assembling an annular segment forming the outer wall of the tunnel, an earth discharging device for discharging the excavated earth and sand, etc. Is incorporated.

  In the shield excavator as described above, the shield jack is pressed against the front end face of the segment already assembled in the previous excavation process, the shield jack is extended, and a tunnel having a length of one stroke of the shield jack is formed. Excavate. Then, using a segment erector, assembling the existing segment to connect the new segment, and repeatedly repeating the operation of pressing the shield jack against the assembled new segment to extend it, the outer wall composed of segments Is constructed.

  When inspecting the inside of the chamber of the shield machine or inspecting the cutter head and the like, it is necessary to open the chamber. When the chamber is opened, groundwater from the ground around the shield machine flows into the shield machine, which may loosen the ground around the shield machine and cause land subsidence or depression. Therefore, in order to perform the inspection safely, groundwater from the surrounding ground for the shield machine must be shut off.

  Conventionally, as a method used to block groundwater, for example, a cement liquid or cement bentonite as an injecting agent, a chemical solution injection method (chemical grouting method) in which the pressure is injected into the ground using a pressure device, from the ground in advance. There is one that performs ground improvement (for example, see Patent Document 1).

JP-A-3-132592

  In the case of blocking the groundwater by the above-mentioned chemical liquid injection method, since the chemical liquid is usually injected from the ground, it may be difficult to inject the chemical liquid from the ground due to restrictions on securing traffic on the ground. Further, when stopping water at a location where the depth of the ground is large, it is difficult to obtain a sufficient water stopping effect.

  The present invention has been made in view of the above problems, and a tunnel water stopping method, a water stopping system, a water stopping material, which can easily and reliably shut off groundwater from the surrounding ground for a shield machine. It is intended to provide grouting material.

The characteristic configuration of the tunnel waterproofing method according to the present invention for solving the above-mentioned problems is as follows:
A tunnel waterproofing method for shielding groundwater from the surrounding ground for a shield machine that excavates the ground and builds a tunnel,
In a state where the excavation of the shield excavator is stopped, the water gap between the fuselage of the shield excavator and the surrounding ground is filled with a waterproof material that allows the shield excavator to re-excavate even if it hardens. It is to include a material filling step.

  In the tunnel water stoppage method of this configuration, for example, when inspecting the inside of the chamber of the shield excavator or inspecting the cutter head, etc., while the excavation of the shield excavator is stopped, the fuselage of the shield excavator and the surrounding ground A water stopping material filling step of filling a water stopping material that can be re-excavated by the shield excavator even if it hardens is performed in the gap between the above. The water-stop material filling process is a process of filling the gap between the shield machine and the surrounding ground with the water-stop material. There is no restriction or the like, and it can be easily implemented. In addition, the filled water-stop material exhibits a sufficient water-stopping effect if it hardens, so that the groundwater from the surrounding ground around the shield excavator, especially the ground around the body of the shield excavator, can be easily and reliably removed. Can be shut off. Further, even if the filled water blocking material hardens, the shield machine can be re-excavated, so that the excavation can be resumed promptly after the inspection work or the like is completed. In this specification, "to block groundwater from the surrounding ground for the shield machine" means that the infiltration of groundwater from the surrounding ground to the shield machine is completely stopped, and the groundwater flowing into the shield machine is This includes, for example, suppressing the inflow of groundwater into the shield machine so that the flow rate is equal to or less than an allowable flow rate at which inspection of the cutter head and the like can be performed safely.

In the tunnel water stopping method according to the present invention,
It is preferable to include a grout material filling step of filling a grout material into a ground crack in front of a face, which is an excavation surface in the excavation direction of the shield machine.

  In the tunnel water stopping method of this configuration, a grout material filling step of filling grout material into a ground crack in front of a face, which is an excavation surface in the excavation direction of the shield machine, is performed. The grout material filling process is a process of filling grout material into the ground crack in front of the face from the shield excavator side, and there is no restriction on securing traffic on the ground compared to the conventional chemical solution injection method that injects chemical solution from the ground. , Can be easily implemented. Therefore, the groundwater from the front face side of the shield machine in the surrounding ground of the shield machine can be easily and reliably shut off.

In the tunnel water stopping method according to the present invention,
It is preferable to include a curing step of curing the water stopping material so that the uniaxial compressive strength is 0.025 to 0.20 N / mm ² .

In the tunnel water stopping method of this configuration, a curing step of curing the water stopping material so that the uniaxial compressive strength is 0.025 to 0.20 N / mm ² is performed. Uniaxial compressive strength of the hardened water stopping material are the order of 0.025~0.20N / mm ^2, surrounding without sticking to the long shield machine excavation stopped can not excavation again shield machine to ground Can support the ground.

Next, the characteristic configuration of the tunnel water stoppage system according to the present invention for solving the above-mentioned problems is as follows.
A tunnel water stopping system for blocking groundwater from the surrounding ground for a shield machine that excavates the ground and builds a tunnel,
In a state where the excavation of the shield excavator is stopped, the water gap between the fuselage of the shield excavator and the surrounding ground is filled with a waterproof material that allows the shield excavator to re-excavate even if it hardens. An object filling device is provided.

  In the tunnel water stop system of this configuration, for example, when inspecting the inside of the chamber of the shield machine or inspecting the cutter head, etc., while the excavation of the shield machine is stopped, the fuselage of the shield machine and the surrounding ground The watertight material filling step of filling the watertight material that can be re-excavated by the shield excavator even if it hardens is performed using the watertight material filling device. The waterproofing material filling process using the waterproofing material filling device is a process of filling the gap between the shield excavator side and the surrounding ground with the waterproofing material, and a conventional chemical liquid injection method of injecting a chemical solution from the ground. In comparison, there is no restriction on securing traffic on the ground, and the present invention can be easily implemented. In addition, the filled water-stop material exhibits a sufficient water-stopping effect if it hardens, so that the groundwater from the surrounding ground around the shield excavator, especially the ground around the body of the shield excavator, can be easily and reliably removed. Can be shut off. Further, even if the filled water blocking material hardens, the shield machine can be re-excavated, so that the excavation can be resumed promptly after the inspection work or the like is completed.

In the tunnel water stopping system according to the present invention,
It is preferable to provide a grout material filling device for filling a grout material into a ground crack in front of a face, which is an excavation surface in the excavation direction of the shield machine.

  In the tunnel water stoppage system having this configuration, a grout material filling step of filling a grout material into a ground crack in front of a face, which is an excavation surface in the excavation direction of the shield machine, is performed using a grout material filling device. The grout material filling process using the grout material filling device is a process of filling grout material into the ground crack in front of the face from the shield excavator side, and compared to the conventional chemical solution injection method of injecting the chemical solution from the ground, There is no restriction on securing traffic, etc., and it can be easily implemented. Therefore, the groundwater from the front face side of the shield machine in the surrounding ground of the shield machine can be easily and reliably shut off.

Next, the characteristic configuration of the water-stopping material according to the present invention for solving the above problems,
In order to cut off groundwater from the surrounding ground for the shield machine that excavates the ground and builds a tunnel, the gap between the fuselage of the shield machine and the surrounding ground is filled, and the shield is hardened even if it hardens. The excavator is a water stoppage material that can be re-excavated,
Contains a curing agent that promotes curing,
The uniaxial compressive strength after curing is to be 0.025 to 0.20 N / mm ² .

According to the water stopping material of the present structure, it includes a curable material to accelerate the curing, the uniaxial compressive strength after curing for a 0.025~0.20N / mm ^2, shield machine excavation stopped again It is possible to support the surrounding ground without fixing the shield machine to the ground so that it cannot excavate. The filled water-stop material exhibits sufficient water-stopping effect when hardened, so it easily and reliably shuts off groundwater from the surrounding ground around the shield machine, especially around the body of the shield machine. can do.

Next, the characteristic configuration of the grout material according to the present invention for solving the above-described problems is as follows:
In order to cut off groundwater from the surrounding ground for the shield machine that excavates the ground and constructs a tunnel, grout material is used to fill the ground crack in front of the face, which is the excavation surface in the excavation direction of the shield machine. So,
A curing agent that promotes curing,
A filling material having an 85% particle size of 10 μm or less according to a particle size accumulation curve measurement,
A fluid expanding agent that increases the volume when the curing proceeds with the curing agent while increasing the fluidity,
Is contained.

  The grout material of this configuration contains a plugging material and a flow expanding agent together with a curing material that promotes curing. The filler has an 85% particle size of 10 μm or less as measured by a particle size accumulation curve measurement. The 85% particle size of the entire grout material measured by a particle size accumulation curve is set to 20 μm or less. Thereby, the plugging material can smoothly pass through the ground crack in front of the face. The fluid expanding agent prevents the agglomeration of the hardening material and the filling material, and increases the volume when the hardening proceeds with the hardening material, so that the hardening material and the filling material can be deeply penetrated into the ground on the face side. At the same time, for example, when the pressure inside the chamber of the shield machine is checked or the pressure is reduced due to the opening of the chamber when inspecting the cutter head, etc., it is necessary to prevent the grout material permeating the ground on the face side from being pulled back to the shield machine. Can be. From the above, according to the grout material of this configuration, even if the chamber of the shield excavator is opened for inspection or the like, the ground crack in front of the face can be reliably closed, and the ground around the shield excavator can be closed. In particular, groundwater from the face side in front of the shield machine can be easily and reliably shut off.

FIG. 1 is a schematic diagram of a muddy shield excavator provided in a tunnel water stoppage method according to a first embodiment of the present invention in a longitudinal sectional direction. FIG. 2 is a flowchart showing a procedure for implementing the tunnel water stopping method according to the first embodiment of the present invention. FIG. 3 is a schematic view of a mud pressure type shield excavator provided in a tunnel water stopping method according to a second embodiment of the present invention in a longitudinal sectional direction. FIG. 4 is a flowchart showing a procedure for implementing a tunnel water stopping method according to the second embodiment of the present invention. FIG. 5 is a graph showing the relationship between the amount of cement (hardening material) and the uniaxial compressive strength. FIG. 6 is a graph showing the measurement results of the grain size accumulation curve of the grout material. FIG. 7 is a graph showing the measurement results of the particle size accumulation curve of the plugging material.

  Hereinafter, the present invention will be described with reference to FIGS. However, the present invention is not intended to be limited to the embodiments described below and the configurations described in the drawings.

(First embodiment)
<Shield excavator>
FIG. 1 is a schematic diagram of a muddy shield excavator provided in a tunnel water stoppage method according to a first embodiment of the present invention in a longitudinal sectional direction. The shield machine 1A shown in FIG. 1 performs excavation while applying mud pressure to the excavated surface (face) in the excavation direction to stabilize the face. The shield machine 1A includes a cylindrical body 2 and a cutter head 3 rotatably supported at a front portion of the body 2, and rotates the cutter head 3 by a rotation driving device (not shown) built in the body 2. By driving, the cutter face can be excavated by the cutter bit 4 or the like mounted on the front side of the cutter head 3. A partition 5 is provided behind the cutter head 3 so as to partition the body 2 back and forth, and a chamber 6 is defined between the partition 5 and the cutter head 3. The chamber 6 is capable of storing muddy water and serves to prevent collapse of the ground due to mud pressure against the soil water pressure of the ground. Inside the fuselage 2, a shield jack for excavation (not shown), a segment elector (not shown) for assembling an annular segment 7 constituting the outer wall of the tunnel, and the like are incorporated. In addition, a gap is generated between the fuselage 2 of the shield machine 1A and the surrounding ground by an amount corresponding to the overcut of the cutter head 3.

  Inside the fuselage 2 of the shield machine 1A, a water-stopping material filling device 11 and a grout material filling device 12 are disposed. When the shield excavator 1A is in the excavation halt state, the water-stopping material filling apparatus 11 allows the shield excavator 1A to re-excavate even in the gap between the fuselage 2 of the shield excavator 1A and the surrounding ground even when it hardens. This is a device for filling a waterproof material 15. On the other hand, the grout material filling device 12 is a device that fills a ground crack in front of a face with grout material 16.

<Water stoppage filling device>
The water-stop material filling device 11 includes a mixing device 21 for mixing the two liquids (the liquid A and the liquid B), and a required water-stop material injection mounted on the outer peripheral wall of the body 2 so as to face the excavated ground. And a nozzle 22. The mixing device 21 has a first port portion 23, a second port portion 24, and a required water-stopping material discharge portion 25 which are arranged in order from the upstream side to the downstream side of the fluid flow. A liquid tank 27 is connected to the first port 23 via a liquid supply pipe 26. A liquid B tank 29 is connected to the second port 24 via a liquid B supply pipe 28. The water shutoff material injection nozzle 22 is connected to the water shutoff material discharge unit 25 via a water shutoff material supply pipe 30.

  In the middle of the A-liquid supply pipe 26, an A-liquid pressure pump 31 for pumping the A-liquid in the A-liquid tank 27 to the mixing device 21 is provided. In the middle of the B-liquid supply pipe 28, a B-liquid pressure pump 32 for feeding the B-liquid in the B-liquid tank 29 to the mixing device 21 is provided. In the middle of each of the A liquid supply pipe 26 and the B liquid supply pipe 28, a pressure switch, a pressure sensor, a flow meter, and the like (not shown) are appropriately provided in addition to the A liquid pressure pump 31 and the B liquid pressure pump 32. It is arranged.

<Grout material filling device>
The grout material filling device 12 is provided with a grout material injection nozzle 41 mounted on the partition wall 5 so that the grout material 16 can be injected into a lower portion of the chamber 6. The grout material injection nozzle 41 is connected to a grout material tank 43 via a grout material supply pipe 42. In the middle of the grout supply pipe 42, a grout feed pump 44 for feeding the grout 16 in the grout tank 43 to the grout injection nozzle 41 is provided. In the middle of the grout supply pipe 42, in addition to the grout feed pump 44, pressure switches, pressure sensors, flow meters, and the like (not shown) are appropriately disposed.

  The water stoppage material 15 and the grout material 16 have different injection times. Therefore, the A liquid tank 27 and the grout material tank 43 are shared by one tank, the A liquid pressure pump 31 and the grout material pressure pump 44 are also shared by one pressure pump, and the A liquid supply pipe 26 and the grout A required opening / closing valve may be provided in the material supply pipe 42 so that the switching of the opening / closing valve switches between the liquid A injection and the grout material injection.

<Water stoppage material>
The A liquid tank 27 stores an A liquid that is an aqueous solution containing a curing agent, an auxiliary material, a stabilizer, and a gelling accelerator. On the other hand, the B liquid tank 29 stores a B liquid as a plasticity adjusting agent (special water glass) for increasing the plastic strength. The water stopping material 15 is formed by mixing the A liquid supplied from the A liquid tank 27 via the A liquid supply pipe 26 and the B liquid supplied from the B liquid tank 29 via the B liquid supply pipe 28 with the mixing device 21. It is prepared by mixing. The water-stopping material 15 gels within 15 to 60 seconds of gel time (time from liquid to plasticity) by mixing the A liquid and the B liquid, secures a viscosity of 200 to 300 dPs, and goes through a curing step. The uniaxial compressive strength after curing becomes 0.025 to 0.20 N / mm ² . The water-stopping material 15 exhibits a sufficient water-stopping effect by hardening, and can support the surrounding ground without fixing the shield excavator 1A to the ground so that the shield excavator 1A in the excavation stopped state cannot excavate again. . Table 1 shows the target properties of the waterproof material 15.

[Curing material]
In the water stopping material 15, a hardening material is used for the purpose of accelerating hardening. The hardening material is a type of hydraulic cement, and is an inorganic material obtained by mixing a calcareous material and a clay material and firing and pulverizing the mixture. The compounding amount of the curing agent is preferably 50 to 110 kg / m ³ , and more preferably 75 to 100 kg / m ³ . In addition, as shown in FIG. 5, when the hardening material is 110 kg / m ^3, it is expected that the uniaxial compressive strength will be about 0.3 N / mm ² . When the uniaxial compressive strength exceeds 0.3 N / mm ² , the shield excavator 1 </ ^b > A in the excavation stopped state may be fixed to the ground so that it cannot excavate again, so the upper limit of the hardened material is about 110 kg / m ^3. . Further, as shown in FIG. 5, when the amount of the hardened material is less than 50 kg / m ³ , the uniaxial compressive strength after hardening is expected to be less than 0.01 N / mm ² . If the uniaxial compressive strength is less than 0.01 N / mm ² , the waterproof material 15 may be drawn into the front side of the shield machine 1 </ ^b > A due to the pressure fluctuation at the time of opening the chamber 6, which may induce the inflow of groundwater. Therefore, the lower limit of the hardening material is about 50 kg / m ³ .

[Aids]
In the water stopping material 15, the auxiliary material is used for the purpose of suppressing breathing and material separation. The auxiliary material is an inorganic material containing sericite (sericite-based clay) and montmorillonite as main components, and is fine and rich in mineral crystals. The amount of the co-material, preferably 150~250kg / ^{m 3,} more preferably from 200~225kg / ^{m 3.}

[Stabilizer]
In the water stopping material 15, the stabilizer is used for the purpose of securing the fluidity of the liquid A and delaying the setting. The stabilizer is a material containing sucrose as a main component. A material that does not hinder the development of strength by instantaneously setting by addition and mixing of a plasticity modifier (Solution B) while delaying the curing by the curing material. It is. The amount of the stabilizer is preferably 3.5 to 10 kg / m ³ , more preferably 4 to 6 kg / m ³ .

[Geling accelerator]
In the water stopping material 15, the gelling promoter is used for the purpose of suppressing water dilution by groundwater. The gelation accelerator is a material containing magnesium chloride and / or calcium chloride as a main component. The amount of the gelling accelerator is preferably 1 to 5 kg / m ³ , more preferably 2 to ³ kg / m ³ .

[Plasticity modifier]
In the water-stopping material 15, the plasticity-regulating agent is a water-glass-based additive having a property in which an additive contained therein acts as a catalyst on the curing mechanism of colloidal silica to adjust the plasticity time and the compressive strength. Material. The compounding amount of the plastic strength adjuster is 20 to 75 L / m ³ , and more preferably 40 to 60 L / m ³ .

<Grout material>
The grout material tank 43 stores the grout material 16 which is an aqueous solution containing a hardening material, a plugging material, and a fluid expanding agent. Table 2 shows the target properties of the grout material 16.

[Curing material]
The hardening material used for the grout material 16 is basically the same as the hardening material used for the water-stopping material 15, and is a kind of hydraulic cements. It is a pulverized inorganic material. The compounding amount of the hardening material is preferably 200 to 270 kg / m ³ , and more preferably 230 to 250 kg / m ³ .

[Clogging material]
In the grout material 16, the filling material is sericite (sericite-based clay) blended as an auxiliary material in the water-stopping material 15, and an inorganic material mainly composed of montmorillonite. In this plugging material, the weight percentage (%) of the amount of soil that passed through a sieve having a certain particle size is plotted on the vertical axis, and the particle size is plotted on the logarithmic scale as the horizontal axis. This material is characterized as a fine particle injecting material having a particle size of 85% by weight and a particle size of 10 μm or less. The amount of weather stripping material is preferably 80~120kg / ^{m 3,} more preferably from 90~110kg / ^{m 3.}

[Flow expanding agent]
In the grout material 16, the flow expanding agent is used for the purpose of increasing the fluidity and increasing the volume when the hardening proceeds with the hardening material. The flow expanding agent is a material containing a lignin sulfonic acid compound (a flow agent), aluminum powder (an expanding agent), and calcium carbonate. The blending amount of the fluid expanding agent is preferably 1 to 3.5 kg / m ³ , and more preferably 2 to ³ kg / m ³ .

<Excavation operation of shield excavator>
In the shield machine 1A, a mud pump (not shown) sends muddy water to the chamber 6 through a mud pipe 51 and applies pressure to counteract the soil water pressure of the ground, thereby stabilizing the face and excavating the excavated earth and sand. Is transported together with the muddy water to a fluid treatment facility (not shown) through a mud pipe 52 by a mud pump (not shown). In the shield excavator 1A, the shield jack is pressed against the front end face of the segment 7 already assembled in the previous excavation process, and the shield jack is extended to form a tunnel having a length of one stroke of the shield jack. Excavate. After that, by using a segment erector, an operation of assembling the new segment 7 with the existing segment 7 is performed, and the operation of pressing the shield jack against the assembled new segment 7 to extend the segment 7 is repeatedly performed. A tunnel having a configured outer wall is constructed. Note that a gap (tail void) is generated between the segment 7 serving as the outer wall of the tunnel and the surrounding ground due to the overcut of the cutter head 3 and the like. In order to prevent land subsidence and adverse effects on existing structures, a backfill material is injected into the tail void by a backfill material injection device (not shown) provided on the tail portion of the fuselage 2 to fix the segment 7.

  In the tunnel construction section, a position for inspecting the inside of the chamber 6 of the shield machine 1A and inspecting the cutter head 3 and the like every predetermined distance (for example, 200 m) (hereinafter, referred to as a “cutter head etc. inspection position”). When the shield excavator 1 </ b> A reaches a check position such as a cutter head, which is determined in advance, it may be necessary to check the cutter head 3 and the like. When inspecting the cutter head 3 and the like, it is necessary to open the chamber 6. When the chamber 6 is opened, groundwater from the ground surrounding the shield machine 1A flows into the shield machine 1A, which may loosen the ground around the shield machine 1A, leading to ground subsidence or depression. Therefore, in order to perform the inspection safely, it is necessary to shut off the groundwater from the surrounding ground to the shield machine 1A by implementing the tunnel waterproofing method described later.

  Groundwater inflow to the shield machine 1A is classified into three types: inflow from behind the shield machine 1A, inflow from around the fuselage 2 of the shield machine 1A, and inflow from the front of the shield machine 1A. . Of these, the inflow of groundwater from behind the shield machine 1A is due to a tail void generated between the segment 7 serving as the outer wall of the tunnel and the surrounding ground, and a backfill material injection device (not shown) By injecting the backfill material into the tail void, it can be reliably prevented. When the backfill material flows out of the tail portion of the shield machine 1A and a predetermined pressure cannot be secured, it is preferable that the backfill material is replenished and injected from the segment 7 after completion of the excavation.

  On the other hand, the inflow of groundwater from around the fuselage 2 of the shield machine 1A and the inflow of groundwater from the front of the shield machine 1A can be prevented by implementing the tunnel waterproofing method described below.

<Tunnel water stopping method>
FIG. 2 is a flowchart showing a procedure for implementing the tunnel water stopping method according to the first embodiment of the present invention. The symbol "S" in FIG. 2 represents a step (the same applies to FIG. 4). The procedure for implementing the tunnel water stopping method will be described below with reference to FIG.

[S1 to S3]
First, when the shield machine 1A reaches the inspection position such as the cutter head ("YES" in S1), the excavation of the shield machine 1A is stopped, and it is determined whether the geology of the ground at the inspection position such as the cutter head is a rock layer. Is determined (S2). In the case of a rock layer ("YES" in S2), inspection and replacement work of the cutter bit 4 cannot be performed in a state where the cutter bit 4 bites into the rock layer, so that inspection work of the cutter head 3 and the like becomes insufficient. For this reason, the shield machine 1A is retracted by a predetermined distance (for example, 50 to 100 mm) so that inspection and replacement work of the cutter bit 4 can be performed (S3). If the geology of the ground at the inspection position such as the cutter head is not a rock layer but a sediment layer ("NO" in S2), the process proceeds to step S4.

[S4: Water-stopping material filling step, curing step]
In step S4, the A liquid in the A liquid tank 27 is pumped to the mixing device 21 by operating the A liquid pressure pump 31 and the B liquid pressure pump 32, and the B liquid in the B liquid tank 29 is operated. To the mixing device 21. Thus, the liquid A and the liquid B are mixed by the mixing device 21 to prepare the water-stopping material 15. The prepared water-stopping material 15 is pressure-fed from the water-stopping material discharge part 25 of the mixing device 21 to the water-stopping material injection nozzle 22 via the water-stopping material supply pipe 30. The pressure-stopped water-stopping material 15 is ejected from the water-stopping material injection nozzle 22 and is filled in a gap between the fuselage 2 of the shield machine 1A and the surrounding ground. The filled water stopping material 15 gels within a gel time of 15 to 60 seconds, a viscosity of 200 to 300 dPs is secured, and after a curing step, a uniaxial compressive strength of 0.025 to 0.20 N / mm ² is developed. You. This makes it possible to support the surrounding ground without fixing the shield excavator 1A to the ground so that the shield excavator 1A in the excavation stopped state cannot excavate again. Groundwater from the surrounding ground around the fuselage 2 of the excavator 1A can be easily and reliably shut off.

[S5 to S8]
Next, the flow rate of the groundwater flowing into the chamber 6 is measured (S5), and it is determined whether or not the measured flow rate exceeds a permissible flow rate set in advance so that the inspection of the cutter head 3 and the like can be performed safely. (S6). If the measured flow rate exceeds the allowable flow rate ("YES" in S6) and the geology of the ground at the inspection position such as the cutter head is a rock layer ("YES" in S7), the muddy water in the chamber 6 is replaced with fresh water. (S8). If the measured flow rate exceeds the allowable flow rate ("YES" in S6) and the ground at the inspection position such as the cutter head is not a rock layer but a sediment layer ("NO" in S7), Proceed to step S9.

[S9: Grout material filling step]
In step S9, the grout material pumping pump 44 is operated to pump the grout material 16 in the grout material tank 43 to the grout material injection nozzle 41. Here, in the case of the bedrock that has undergone the replacement of fresh water in the chamber 6 in step S8, when a grout material 16 of a proper composition is injected into the fresh water into the chamber 6, the ratio of water to hardened material (W / C ) Is a poorly mixed (W / C> 1000%) grout material 16 having a large amount of hardening material. As described above, the cracks on the rock surface are gradually replaced with the grout material 16 having a proper composition from the most easily penetrated Shimizu and completely replaced with the Shimizu (W / C = (883/240) × 100 = 368). %), Grout material 16 is injected until the flow rate is constant. In addition, in the case of the earth and sand that has not been subjected to the fresh water displacement in the chamber 6 in step S8, the grout 16 is not gradually subjected to the fresh water process, and the grout material 16 is gradually mixed with the regular mixture from the mud without undergoing the fresh water process. After the grout material 16 is injected into the chamber 6 and completely replaced with the muddy water, the grout material 16 is injected until the injection flow rate becomes constant, and the grout material 16 is sufficiently penetrated into the ground.

The injection flow rate of the grout material 16 differs depending on the hydraulic conductivity and pressure difference of the target ground. When the crack is large (has a large hydraulic conductivity), it is necessary to inject a large amount of the grout material 16. In the case where the crack is small (the water permeability is small), it is stabilized by injecting a small amount of the grout material 16. As shown in Table 3 below, when the hydraulic conductivity of the target ground is 1 × 10 ⁻⁴ to 1 × 10 ⁻³ m / s, the injection flow rate of the grout material 16 is 466.5 to 4665.3 L / min. When the hydraulic conductivity of the target ground is 1 × 10 ⁻⁷ to 1 × 10 ⁻⁵ m / s, the injection flow rate of the grout material 16 is 0.5 to 46.7 L / min. From the viewpoint of the discharge capacity of the grout material pump 44, the above grout material filling step is effective for the ground having a water permeability of 1 × 10 ⁻⁷ to 1 × 10 ⁻⁵ m / s. In addition, if a crack having a width of about 0.5 to 1 mm in the face can be blocked by the grout material 16, the inflow of groundwater can be considerably reduced.

  If the measured flow rate of the groundwater flowing into the chamber 6 becomes equal to or less than the allowable flow rate which is set in advance so that the inspection of the cutter head 3 and the like can be performed safely by performing the grout material filling step in step S9 (step S6). In step S10), the chamber 6 of the shield machine 1A is opened, and the inside of the chamber 6 and the cutter head 3 are inspected (S10). Even when the chamber 6 is opened, it is possible to prevent the grout material 16 that has permeated the ground on the face side from being pulled back to the shield machine 1A due to the action of the fluid expanding agent contained in the grout material 16. Therefore, even if the chamber 6 of the shield machine 1A is opened for inspection or the like, the ground crack in front of the face can be reliably closed, and among the ground around the shield machine 1A, particularly, the shield machine 1A Groundwater from the front face side can be easily and reliably shut off.

  If the measured flow rate of the groundwater flowing into the chamber 6 becomes equal to or less than the allowable flow rate by performing the water stopping material filling step in step S4, the chamber 6 of the shield machine 1A is removed without performing the grout material filling step. After opening, the inside of the chamber 6 and the cutter head 3 are inspected (S5, S6, S10).

  The shield excavator 1A in the excavation stopped state for inspection of the cutter head 3 and the like is not fixed to the ground by the water-stopping material 15 so that it cannot excavate again, and can be excavated again. Excavation can be resumed promptly.

(Second embodiment)
FIG. 3 is a schematic view of a mud pressure type shield excavator provided in a tunnel water stopping method according to a second embodiment of the present invention in a longitudinal sectional direction. In the second embodiment, the same or similar components as those in the first embodiment will be denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted. In the following, parts unique to the second embodiment will be described. Will be mainly described.

<Shield excavator>
The shield machine 1B shown in FIG. 3 excavates the excavated earth and sand by using an additive material, and applying predetermined pressure to the excavated earth to stabilize the face. In the shield machine 1 </ b> B, the earth speed is maintained by controlling the excavation speed and the earth removal amount, and the screw conveyor is connected to the lower part of the chamber 6 by being inclined upward and rearward so as to communicate with the lower part of the chamber 6. The amount of earth removal is controlled by increasing or decreasing the number of rotations of 60. In some cases, the original particle size distribution of the ground is good and the additive is not used. In this case, the shield machine 1B functions as an earth pressure shield machine.

  The shield machine 1 </ b> B includes a waterproof material injection nozzle 45 mounted on the partition wall 5 so that the waterproof material 15 can be injected into the chamber 6. The water-stop material injection nozzle 45 and the mixing device 21 are connected by a water-stop material supply pipe 46. Thereby, the water-stopping material 15 prepared by the mixing device 21 is pressure-fed from the mixing device 21 to the water-stopping material injection nozzle 45 via the water-stopping material supply pipe 46. The water-stopping material 15 that has been pressure-fed is injected into the chamber 6 from the water-stopping material injection nozzle 45. In the shield machine 1B, a grout material filling device 62 having a configuration different from that of the grout material filling device 12 provided in the shield machine 1A of the first embodiment is provided. The grout material filling device 62 includes a required grout material injection nozzle 63 mounted on the front side of the cutter head 3 so that the grout material 16 can be injected directly into the face. The grout material injection nozzle 63 is connected to a grout material tank 65 via a grout material supply pipe 64 including a required swivel joint (not shown) and extending to the rear of the body 2 through the center of the cutter head 3. Have been. In the middle of the grout supply pipe 64, a grout feed pump 66 for feeding the grout 16 in the grout tank 65 to the grout injection nozzle 63 is provided. In the middle of the grout supply pipe 64, a pressure switch, a pressure sensor, a flow meter, and the like (not shown) are appropriately disposed in addition to the grout feed pump 66.

<Tunnel water stopping method>
FIG. 4 is a flowchart showing a procedure for implementing a tunnel water stopping method according to the second embodiment of the present invention. The procedure from step S1 to step S7 in FIG. 4 is exactly the same as that in FIG. 2, and therefore the description is omitted, and the procedure from step S21 to step S23 will be mainly described.

[S21]
If the measured flow rate in step S5 exceeds the allowable flow rate ("YES" in S6), the interior of the chamber 6 and the like are replaced with an impermeable layer (S21). That is, in the case of the mud pressure shield excavator 1B, when the pressure in the chamber 6 is increased, the pressure may escape from the screw conveyor 60 to the working room side of the body 2. At this time, the water stopping material filling device 11 injects the water stopping material 15 from the mixing device 21 into the chamber 6 through the water stopping material supply pipe 46 and the water stopping material injection nozzle 45, and the injected water stopping material 15 and the chamber The pressure in the chamber 6 is maintained by mixing the earth and sand in the chamber 6 and replacing the chamber 6 and the screw conveyor 60 with an impermeable layer. The mixing ratio of the water stopping material 15 with the earth and sand is preferably 30% or more.

[S22]
If the measured flow rate in step S5 exceeds the allowable flow rate ("YES" in S6) and the geology of the ground at the inspection position such as the cutter head is a rock layer ("YES" in S7), the front surface of the cutter head 3 The space is filled with fresh water (S22). Fresh water is injected and filled instead of the additive from an additive injection nozzle (not shown) for injecting the additive.

[S23: Grout material filling step]
When the fresh water is filled in step S22, the grout material pump 66 in the grout material filling device 62 is operated to pump the grout material 16 in the grout material tank 65 to the grout material injection nozzle 63. As a result, the grout material 16 having a proper composition is gradually injected from the fresh water between the face and the cutter head 3, and after the grout material 16 is completely replaced with the fresh water, until the grout material 16 is injected at a constant flow rate. The grout material 16 is injected so that the grout material 16 sufficiently penetrates into the ground.

  Next, specific examples of the tunnel water stopping method, the tunnel water stopping system, the water stopping material, and the grout material of the present invention will be described.

<Water stoppage material>
A water-stopping material was prepared at a blending amount per 1.05 m ³ shown in Table 4 below. Here, the manufacturing companies and product names of the hardening material, the auxiliary material, the stabilizer, the gelling accelerator, and the plasticity adjusting agent are as follows.
Curing material: Tack Co., Ltd., "Tackment"
Auxiliary material: Tac Co., Ltd., "TAC-βII"
Stabilizer: Tac Corporation, "TAC-Re"
Gelling accelerator: Tac Corporation, "TAC Gel"
Plasticity modifier: Tac Corporation, "TAC-3G"

  In the formulations shown in Table 4, both the case where the amount of the gelation accelerator is changed while the amount of the solution B is kept as it is and the case where the amount of the gelation accelerator is reduced and the gelation accelerator is not added are used. Table 5 shows the properties of the waterproof material.

In addition, Table 6 shows the properties of the mixing ratio of the water-stopping material and the earth and sand of 30% in the case of 50 L and 20 L of the liquid B per 1.05 m ³ .

As is evident from the results shown in Tables 5 and 6, the waterproof material of the present invention maintains the uniaxial compressive strength at about 0.1 N / mm ^2, so that the shield excavator in the excavation stopped state excavates again. It can support the surrounding ground without sticking the shield machine to the ground unnecessarily. The impermeable layer obtained by mixing earth and sand (water permeability: 1.1 × 10 ⁻⁴ m / s) and a water-stopping material has a water permeability of 2.4 × 10 ^{−7 to} 4.9 × 10 ^{−. About 7} has been achieved.

<Grout material>
A grout material was prepared in a blending amount per 1 m ³ shown in Table 7 below. Here, manufacturing companies and product names of the hardening material, the plugging material, and the fluid expanding agent are as follows.
Product name Curing material: Tack Co., Ltd., "Tackment"
Filling material: Tac Corporation, "TAC-βII"
Fluid expander: Tack Co., Ltd., "FTA-S"

  Table 8 shows the properties of the grout materials prepared according to the formulations shown in Table 7.

  The above grout material was subjected to a particle size analysis by a laser diffraction / scattering method (dig site: LA-920). As a result, the 85% particle size of the grout material by the particle size accumulation curve measurement shown in FIG. (A particle diameter corresponding to a weight ratio of 85%) was about 14 μm, and it was confirmed that the powder had a particle diameter close to that of the fine particle injection material. FIG. 7 also shows that the 85% particle size of the plugging material is 10 μm or less (measured value 7.5 μm).

  There is a groutability ratio (GR) as an index for evaluating whether or not the infiltration is possible based on the particle size of the grout material and the particle size of the ground to be injected. If the value of GR = D15 / G85 is 15 to 25 or more, the grout material 16 becomes It is possible to penetrate the ground to be injected. Here, D15 is a 15% particle size determined by measuring the particle size accumulation curve of the ground, and G85 is an 85% particle size determined by measuring the particle size accumulation curve of the grout material.

  When the permeation area of the grout material is calculated in reverse, D15 = GR × G85 = (15 to 25) × 14 μm = 210 to 350 μm, and the 15% particle diameter by the particle diameter accumulation curve measurement of the ground can penetrate to about 210 to 350 μm. It turns out that it is. Since this corresponds to the crack width of the bedrock, the grout material of the present invention can penetrate the crack width to 1 mm or less, and further to about 0.5 mm.

  INDUSTRIAL APPLICABILITY The tunnel waterproofing method, tunnel waterproofing system, waterproofing material, and grout material of the present invention can be used in an application for shielding groundwater from the surrounding ground for a shield excavator that excavates a ground and constructs a tunnel. .

DESCRIPTION OF SYMBOLS 1A, 1B Shield excavator 2 Body 11 Water-stopping material filling device 12 Grout material filling device (first grout material filling device)
15 Water stop material 16 Grout material 62 Second grout material filling device

Claims (6)

A torso, and a cutter head rotatably supported at a front portion of the torso ; groundwater from a surrounding ground for a shield excavator that constructs a tunnel by rotating the cutter head and excavating the ground to construct a tunnel; Tunnel water blocking method to cut off
In a state in which the excavation of the shield excavator is stopped, the gap formed by the overcut of the cutter head between the fuselage of the shield excavator and the surrounding ground can be re-excavated even if it hardens. A tunnel water stopping method including a water stopping material filling step of filling a water stopping material.   2. The tunnel water stopping method according to claim 1, further comprising a grout material filling step of filling a grout material into a ground crack in front of a face, which is an excavation surface in an excavation direction of the shield machine. 3. Tunnel waterproofing method of claim 1 or 2 comprising a curing step of curing the water stopping material as uniaxial compressive strength is 0.025~0.20N / mm ^2. A torso, and a cutter head rotatably supported at a front portion of the torso ; groundwater from a surrounding ground for a shield excavator that constructs a tunnel by rotating the cutter head and excavating the ground to construct a tunnel; A tunnel water stop system for blocking
In a state in which the excavation of the shield excavator is stopped, the gap formed by the overcut of the cutter head between the fuselage of the shield excavator and the surrounding ground can be re-excavated even if it hardens. Tunnel water stoppage system equipped with a water stoppage material filling device that fills various water stoppage materials.   5. The tunnel water stopping system according to claim 4, further comprising a grout material filling device that fills a grout material into a ground crack in front of a face, which is an excavation surface in the excavation direction of the shield machine. A torso, and a cutter head rotatably supported at a front portion of the torso ; groundwater from a surrounding ground for a shield excavator that constructs a tunnel by rotating the cutter head and excavating the ground to construct a tunnel; In order to cut off the water, the gap between the fuselage of the shield machine and the surrounding ground is filled in the space created by the overcut of the cutter head. And
Contains a curing agent that promotes curing,
A water-blocking material having a uniaxial compression strength of 0.025 to 0.20 N / mm ² after curing.

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