JP5826347B2 - Fluid transport method of excavated soil using foam suppressor in bubble shield method - Google Patents

Description

  The present invention relates to a bubble shield method.

A bubble shield method has been proposed as one of the shield methods for excavating natural ground and building tunnels.
In the bubble shield method, air bubbles generated by foaming a liquid containing foaming agent are injected between the face and the cutter or into a chamber for storing excavated soil excavated by the cutter, and the ground is removed by the cutter. Drilling is performed (see Patent Documents 1 and 2).

JP-A-2005-76285 JP 2006-348727 A

Conventionally, in this type of bubble shield method, the excavated soil with a cutter becomes a bubbled soil mixed with bubbles, so an antifoaming agent (foam breaker) for defoaming bubbles in the excavated soil is used in the air. After spraying, it is necessary to discharge with a cart or belt conveyor.
For this reason, labor is required for the excavation soil transfer process, and the transfer equipment becomes complicated, which increases costs and is disadvantageous in saving labor. Furthermore, since the antifoaming agent is sprayed into the air, it is difficult to spread the foamed soil evenly.
The present invention has been made in view of such circumstances, and is intended to improve defoaming reliability, safety, and workability in transferring excavated soil containing bubbles discharged in the bubble shield method. An object of the present invention is to provide a fluid transport method for excavated soil using an antifoaming agent (foam suppressor) in the bubble shield method which is advantageous in the above.

The present invention excavates natural ground with a cutter while injecting bubbles generated by foaming a liquid containing a foaming agent between the face and the cutter or into a chamber for storing excavated soil excavated by the cutter. A first step of mixing the first mud water with the bubbled soil made of excavated soil discharged from the chamber and mixed with the bubbles to form the second mud water, and the second mud water And a first step of injecting a defoamer for defoaming bubbles into the first mud prior to the first step. foams implantation step, or the second foam injection step of injecting the foam inhibitors after the first step to the second mud, or the first foam injection step and the a step of executing both the second foam injection step, the said first step Between 2 steps, the second gravel contained in the mud and a crushing step of crushing by crusher, mud the gravel has removed the gravel fraction and sand fraction from crushed the second mud transported, provided adjustment tank to store as said first mud by diluting the muddy water with fresh water is to monitor the amount of air bubbles contained in the prior SL first mud before Symbol adjusting tank, the monitoring result And the amount of the foam inhibitor injected into the first mud in the first foam inhibitor injection step and the second mud water injected in the second foam inhibitor injection step. in the bubble shield method, wherein that controls the injection amount of foam inhibitor, using foam inhibitor, a fluid transport methods excavated soil.

Prior to the first step, a first defoaming agent injection step of injecting a defoaming agent for defoaming bubbles into the first mud water, or a second defoaming agent after the first step. The second antifoaming agent injection step for injecting into the muddy water, or both the first antifoaming agent injection step and the second antifoaming agent injection step were performed .
Accordingly, since bubbles contained in the second mud water are reduced, the occurrence of cavitation in the mud pump can be suppressed, and the second mud water can be stably and reliably transferred.
For this reason, the excavated soil containing bubbles can be smoothly transferred to the fluid, which is advantageous in improving defoaming reliability, safety, and workability.
In addition, while monitoring the amount of bubbles contained in the first mud in the adjustment tank, the amount of foam inhibitor injected into the first mud and the second mud are injected based on the monitoring result. This will control the amount of the foam inhibitor injected . Therefore, since it is easy to monitor the amount of bubbles contained in the first mud water in the adjustment tank, the injection amount of the foam inhibitor necessary for defoaming the bubbles of the second mud water is appropriately set. And it is advantageous for easy management.

It is explanatory drawing which shows the installation for enforcing the bubble shield construction method in embodiment. It is explanatory drawing which shows the structure of the foaming installation.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram of the bubble shield method of the present embodiment.
The bubble shield construction method in the present embodiment is carried out using the shield machine 10, the foaming equipment 30 (FIG. 2), the fluid transportation equipment 42, and the muddy water treatment equipment 62.
In FIG. 1, reference numeral 1 indicates a starting shaft excavated in a vertical direction with respect to the ground, and reference numeral 2 indicates a tunnel excavated from the starting shaft 1 in a horizontal direction by a shield machine 10. Moreover, the code | symbol G shows the ground.

The shield machine 10 excavates the tunnel 2 by drilling a natural ground and assembles a segment ring by assembling a plurality of segments 4 at the end of the tunnel housing 5 already assembled in the rear part of the shield machine 10. The tunnel housing 5 is extended.
The shield machine 10 includes an excavation part 12 and a tail part 14.

The excavation unit 12 includes a cutter device 16, a partition wall 18, a conveyor device 20, a jack device 22, a steel shell 24, and the like.
The cutter device 16 is configured to excavate the ground by rotating a disc-shaped cutter 1602 disposed at the front end of the excavation unit 12 around an axis parallel to the excavation direction.
The partition wall 18 is provided behind the cutter device 16, and a chamber 28 is formed between the partition wall 18 and the back surface of the cutter device 16 for storing excavated soil discharged by excavating the ground by the cutter device 16.
The conveyor device 20 is configured to convey excavated soil stored in the chamber 28 to a joining pipe 44 described later. For example, a screw conveyor can be used as the conveyor device 20.
The jack device 22 is configured to push the shield machine 10 in the digging direction by pressing the location of the segment 4 that is annularly assembled to the tunnel 2 excavated by the cutter device 16 toward the rear in the digging direction. .
The steel shell exterior wall 24 has a cylindrical shape facing the inner wall of the tunnel 2, and houses the front portion of the conveyor device 20 and the jack device 22 in a cylindrical space formed inside the steel shell exterior wall 24. .

The tail portion 14 has a cylindrical shape and includes a steel shell exterior wall 26.
The steel shell outer wall 26 has a cylindrical shape facing the inner wall of the tunnel 2, is connected to the rear end of the steel shell outer wall 24 of the excavation part 12 in the digging direction, and is formed inside the inner side surface 2604 of the steel shell outer wall 26. The rear part of the conveyor device 20 is accommodated in a cylindrical space.

  The shield machine 10 further includes a control unit for operating the cutter device 16, the conveyor device 20, the jack device 22, a drive source, an oil tank, and the like, which are connected to the rear portion of the tail portion 14. Further, they are distributed in a plurality of equipment vehicles for shield machines (not shown). These equipment vehicles for a plurality of shield machines are provided so as to be movable on rails 6 extending in the longitudinal direction of the tunnel 2.

As shown in FIG. 2, the foaming facility 30 injects bubbles in the form of shaving cream produced by foaming water (liquid) containing a foaming agent between the face and the front surface of the cutter 1602, or a chamber 28 is injected.
The foaming facility 30 includes a foaming agent storage tank 32, a foaming agent injection pump 34, a compressor 36, a bubble control device 38, a foaming device 40, and the like.
Each of these devices is distributed in a plurality of equipment vehicles for foaming equipment (not shown) connected to the rear part of the tail part 14. The equipment vehicles for the plurality of foaming equipment are also provided so as to be movable on the rail 6 in the same manner as the equipment vehicles for the shield machine.

The foaming agent storage tank 32 temporarily stores the foaming agent supplied from the foaming agent supply pipe 3202 drawn into the tunnel 2.
The foaming agent injection pump 34 is for transferring the foaming agent supplied from the foaming agent storage tank 32 to the bubble control device 38.
The compressor 36 supplies compressed air to the bubble control device 38.
The bubble control device 38 supplies the foaming device 40 by controlling the flow rates of the foaming agent and the compressed air, respectively.
The foaming device 40 generates a shaving cream-like bubble from the foaming agent and compressed air supplied from the bubble control device 38.
Bubbles generated by the foaming apparatus 40 are supplied between the face and the front surface of the cutter 1602 via the bubble injection tube 4002 or are supplied to the chamber 28.
Therefore, the excavated soil excavated by the cutter device 16 becomes a cellular soil in which bubbles are mixed.

As shown in FIG. 1, the fluid transportation facility 42 transports excavated soil (bubble soil) excavated and discharged by the shield machine 10 together with mud and transports it from the tunnel 2 to the ground G through the start shaft 1. It is.
The fluid transport equipment 42 includes a foam suppressor injection device 43, a merge pipe 44, a mud pipe 46, a mud pump 48, a mud pipe 50, a crusher 52, a flow divider 54, and a plurality of mud muds. A pump 56, a circulation pipe 58, a circulation pump 60, and a control panel 61 are included.

The junction pipe 44 includes first, second, and third openings 44A, 44B, and 44C that communicate with each other.
The first opening 44 </ b> A is connected to the downstream end of the conveyor device 20.
The second opening 44B is connected to the downstream end of the mud pipe 46 that transfers the first mud water from the adjusting tank 66 (described later) that stores the first mud water to the junction pipe 44.
The third opening 44 </ b> C is connected to the upstream end of the mud pipe 50 which is provided with a plurality of mud pumps 56 and transports the second mud water from the junction pipe 44 to the outside of the tunnel 2.
The merging pipe 44 merges and mixes the cellular soil supplied from the conveyor device 20 to the first opening 44A and the first mud water supplied from the mud pipe 46 to the second opening 44B. The second muddy water mixed with the first muddy water is supplied to the mud discharge pipe 50 from the third opening 44C.

  The mud pump 48 is provided near the adjustment tank 66 of the mud pipe 46, and transfers the first mud water stored in the adjustment tank 66 to the junction pipe 44 through the mud pipe 46.

In a position near the merging pipe 44 of the mud pipe 46, in other words, at the position of the mud feeding pipe 46 located on the upstream side of the second opening 44B of the merging pipe 44, the foam inhibitor injection device 43 is installed. Then, the foam inhibitor is injected from the foam inhibitor injection device 43 into the first mud flowing through the mud pipe 46.
If the antifoaming agent is previously dispersed in the muddy water, it inhibits the stability of the thin film of bubbles in the muddy water and makes it impossible to generate bubbles (defoaming).
As such an antifoaming agent, for example, various conventionally known antifoaming agents such as an emulsion type antifoaming agent can be used.

  A crusher 52, a flow divider 54, and a plurality of drainage pumps 56 are arranged in this order from upstream to downstream in the drainage pipe 50, and the downstream end is connected to a vibration sieve device 64 described later. Has been.

  In the present embodiment, the crusher 52 is provided on a dedicated vehicle 5202, and the dedicated vehicle 5202 can move on the rail 6 in the same manner as the equipment vehicle for the shield machine and the equipment vehicle for the foaming equipment. Is provided.

The crusher 52 crushes and discharges gravel contained in the second mud water into which the foam suppressor supplied from the third opening 44C of the junction pipe 44 is injected.
In addition, when the size of the gravel contained in the excavated soil discharged by excavating the natural ground by the shield machine 10 is small and the second mud containing the gravel can be transported by the mud pump 56 without any trouble, the crusher There is no need to crush gravel by 52. Therefore, in such a case, the crusher 52, the flow divider 54, and the circulation pump 60 can all be omitted.

The flow divider 54 includes a muddy water inlet 54A, a first muddy water outlet 54B, and a second muddy water outlet 54C that communicate with each other.
The flow divider 54 has a path for discharging the second mud injected with the foam suppressor supplied from the muddy water inlet 54A to the first muddy water outlet 54B, and the second muddy water supplied to the muddy water inlet 54A. Are provided with two paths, namely, a bypass path that leads to the second muddy water discharge port 54C.

  The plurality of mud discharge pumps 56 transfer the second mud drained from the gravel discharged from the first mud drain outlet 54B of the flow divider 54 to the vibrating sieve device 64 via the mud pipe 50. is there.

The circulation pipe 58 connects the second mud discharge port 54 </ b> C of the flow divider 54 to the middle part of the mud pipe 46.
The circulation pump 60 is provided in an intermediate part of the circulation pipe 58 and supplies the second mud supplied from the second mud discharge outlet 54C of the flow divider 54 to the intermediate part of the mud pipe 46.

The control panel 61 controls the operations of the foam inhibitor injection device 43, the mud pump 48, the crusher 52, the flow divider 54, the plurality of mud pumps 56, and the circulation pump 60.
The control panel 61 includes operation switches for operating the foam suppressor injection device 43, the mud pump 48, the crusher 52, the flow divider 54, the plurality of mud pumps 56, the circulation pump 60, and the like. Control is performed by operating these operation switches.
In the present embodiment, the circulation pump 60 and the control panel 61 are provided on a dedicated vehicle 6002, and the dedicated vehicle 6002 is dedicated to the above-described shield machine equipment vehicle, foam equipment equipment vehicle, and crusher 52. The vehicle 5202 is provided so as to be movable on the rail 6 like the vehicle 5202 of FIG.

  The muddy water treatment facility 62 is disposed on the ground G, and includes a vibration sieving device 64, an adjustment tank 66, a raw water tank 68, a PAC tank 70, a mud storage tank 72, a driving pump 74, and a filter press device 76. And the filtrate water tank 78 and the fresh water tank 80 are comprised.

The vibration sieving device 64 screens the second mud transferred from the first mud discharge port 54B of the flow divider 54 through the mud pipe 50 by the operation of the mud pump 48 to remove gravel and sand. Is.
The second mud from which gravel and sand have been removed is transferred from the vibrating screen device 64 to the adjustment tank 66 as the first mud containing fine particles of silt, clay, and colloid less than 75 microns.
The gravel and sand a removed by the vibration sieving device 64 are carried out using a hydraulic excavator A and a dump truck B.

The adjustment tank 66 stores the first mud water transferred from the vibrating screen device 64 through the water pipe 65 and is diluted by the fresh water transferred from the fresh water tank 80.
The raw water tank 68 stores the first mud transferred from the adjusting tank 66 through the water pipe 67 as surplus mud.

The mud storage tank 72 stores the excess mud transferred from the raw water tank 68 through the water pipe 69 as waste mud, and the flocculant transferred from the PAC tank 70 through the transfer pipe 71 is input to the waste mud. By mixing and stirring, silt, clay, colloidal fine particles contained in the waste mud are aggregated and precipitated.
The flocculant is a chemical used to remove turbidity and color of water. It works by attaching fine particles suspended in water to create a floc (agglomeration), and separating and removing by sedimentation and filtration. There is. As the flocculant, various conventionally known flocculants such as PAC (polyaluminum chloride) can be used.

The driving pump 74 transfers muddy water containing fine particles that have aggregated and settled in the lower part of the mud storage tank 72 to the filter press device 76 via the water supply pipe 75.
The filter press device 76 obtains the dewatered cake b by dewatering the transferred muddy water. The dewatered cake b is carried out to the treatment plant using the excavator D and the dump truck E.

The filtrate water tank 78 temporarily stores the filtrate (water) removed by the filter press device 76.
The fresh water tank 80 stores the water transferred from the filtrate water tank 78 through the water supply pipe 79 as fresh water.

Next, the operation of the fluid transportation facility 42 which is the gist of the present invention will be described.
Before the excavation of the ground by the shield machine 10 is started, all of the mud pump 48, the foam inhibitor injection device 43, the crusher 52, the plurality of mud pumps 56, and the circulation pump 60 are in a stopped state. .

Before the excavation of the ground by the shield machine 10 is started, by operating the operation switch of the control panel 61, the foam inhibitor injection device 43, the crusher 52, and the plurality of mud pumps 56 are operated.
When the excavation of the ground by the shield machine 10 is started, the cellular soil discharged from the conveyor device 20 joins and is mixed with the first mud containing the foam suppressor in the joining pipe 44 to become the second mud.
In other words, the first step is carried out by mixing the first mud containing foam suppressant with the bubble soil made of excavated soil discharged from the chamber 28 and mixed with the bubbles to obtain the second mud.

  In this way, most of the bubbles contained in the second mud water are defoamed by mixing the cellular soil and the first mud water containing the foam suppressant to form the second mud water.

The second mud water from which most of the bubbles are defoamed is crushed in the crusher 52 and then transferred to the flow divider 54. The plurality of mud pumps 56 pass the mud pump 50 through the mud pipe 50 to the vibrating screen device 64. Be transported.
In other words, a second step of transferring the second mud water to the outside of the tunnel 2 using the mud pump 56 is performed. Moreover, in this Embodiment, the crushing process which crushes the gravel contained in 2nd mud water with the crusher 52 between the said 1st process and the said 2nd process is performed.

According to the present embodiment, most of the bubbles are removed by mixing the foam mud and the first mud containing the foam suppressor, and then the second mud is removed by the plurality of mud pumps 56. It was made to transfer to the muddy water treatment facility 62 through the mud drain pipe 50.
Therefore, since the bubbles contained in the second mud water are reduced, the occurrence of cavitation in the mud pump 56 can be suppressed, and the second mud water can be stably and reliably transferred.
Therefore, the second mud water is smoothly and reliably transferred by the plurality of the mud pumps 56 to smoothly transfer the excavated soil containing bubbles.
Therefore, since the excavated soil containing bubbles discharged from the shield machine 10 can be smoothly transferred in the bubble shield method, the defoaming reliability, safety, and workability can be improved in the excavated soil transfer. It is advantageous in planning.
In particular, the defoaming is more reliable compared to the case where the excavated soil is sprayed and defoamed on the excavated soil containing bubbles, and then the excavated soil is transferred using a cart or a belt conveyor. This is advantageous in improving safety and workability.

When an antifoaming agent (foam breaker) is sprayed on the first mud water instead of the foam suppressor, only bubbles that are in contact with the atmosphere can be removed. In the pump 48, the mud pump 56, and the circulation pump 60, cavitation caused by bubbles in the mud water may occur, and the pumps may not operate normally.
On the other hand, in the present embodiment, by using a foam suppressor, it is possible to inhibit the stability of the thin film of bubbles in the muddy water and make it impossible to generate bubbles. This can be suppressed, and is advantageous for smoothly transferring or circulating muddy water.

Further, in the present embodiment, suds suppressors the first mud bubbles soil discharged from the addition from the conveyor device 20 and the first is obtained by mixing the mud, as shown below, mud treatment facility You may make it mix a foam suppressant in a 1st mud in any place from 62 to a pit.
In other words, you may perform the 1st foam inhibitor injection | pouring process which inject | pours the foam inhibitor which defoams bubbles into a 1st mud prior to a 1st process.
That is, a foam inhibitor may be injected and mixed into the first mud stored in the adjustment tank 66.
Alternatively, the foam suppressant may be injected immediately after the cellular soil and the first mud are mixed, and the foam suppressor may be mixed with the first mud.
In short, if the bubbles contained in the second mud transferred by the mud discharge pipe 50 can be eliminated, the foam suppressor is injected into the second mud, the first mud, or the first It is arbitrary whether it inject | pours into both 1st and 2nd mud water.
That is, prior to the first step, the first antifoaming agent injection step of injecting a defoaming agent for eliminating bubbles into the first mud water, or the second antifoaming agent after the first step. It is optional to perform either the second foam inhibitor injection process for injecting into the muddy water, or both the first foam inhibitor injection process and the second foam inhibitor injection process.

Although most of the bubbles in the second muddy water can be removed by the foam suppressor, the bubbles cannot be completely removed, and some of the bubbles remain.
If the amount of bubbles remaining in the second muddy water is large, there is a concern that the second muddy water may not be smoothly transferred by the plurality of mud pumps 56.
For this reason, the amount of bubbles contained in the second mud is not suppressed while monitoring the amount of bubbles contained in the second mud so that the plurality of mud pumps 56 do not affect the transfer of the second mud. It is preferable to control the amount of foaming agent injected.
However, since the second mud passes through the crusher 52 and the mud pipe 50, it is not easy to monitor the amount of bubbles.
On the other hand, since the first mud stored in the adjustment tank 66 is obtained by removing gravel from the second mud by the vibrating sieve 64, if the amount of bubbles contained in the first mud is monitored, In particular, the amount of bubbles contained in the second mud can be monitored.
Therefore, if the amount of bubbles contained in the first muddy water in the adjustment tank 66 is monitored to control the amount of the foam inhibitor injected into the first muddy water in the adjustment tank 66, the second muddy water is substantially converted into the second muddy water. The amount of foam contained can be controlled by monitoring the amount of bubbles contained.
In this case, since it is easy to monitor the amount of bubbles contained in the first mud water in the adjustment tank 66, it is possible to easily manage the injection amount of the foam suppressant, which is preferable.

  2 ... Tunnel, 1602 ... Cutter, 20 ... Conveyor device, 28 ... Chamber, 43 ... Foam suppressor injection device, 44 ... Merge pipe, 44A ... First opening, 44B ... Second Opening, 44C ... third opening, 46 ... mud pipe, 50 ... mud pipe, 52 ... crusher, 54 ... divider, 56 ... mud pump, 66 ... regulator.

Claims (4)

A bubble shield method that excavates natural ground with a cutter while injecting bubbles generated by foaming a liquid containing a foaming agent between the face and the cutter or into a chamber for storing excavated soil excavated by the cutter. Because
A first step of mixing the first mud water with the bubbled soil made of excavated soil discharged from the chamber and mixed with bubbles to form a second mudwater;
A second step of transferring the second mud water to the outside of the tunnel using a mud pump;
Prior to the first step, a first antifoaming agent injection step of injecting a defoaming agent for defoaming bubbles into the first mud water, or the antifoaming agent after the first step. the second foam injection step of injecting the second mud or a step of performing both said first foam injection step and the second foam injection process,
A crushing step of crushing gravel contained in the second mud water with a crusher between the first step and the second step;
The gravel is gravel fraction and muds to remove the sand fraction is transferred from the second mud is crushed, adjusting tank to store as said first mud by diluting the muddy water with clean water is provided,
Monitoring the amount of air bubbles contained in the prior SL first mud before Symbol adjusting tank, the depression is injected into the first mud in the based on the monitoring results the first foam injection process that controls the injection amount and the injection amount of the foam inhibitors in the second foam injection process is injected into the second mud foams,
A fluid transport method for excavated soil using a foam suppressor in the bubble shield method. The cellular soil is discharged from the chamber by a conveyor device,
A confluence pipe that mixes the cellular soil and the first mud to create the second mud is connected to the conveyor device,
A mud pipe for transferring the second mud water from the merging pipe to the outside of the tunnel by the mud pump is provided,
The method for transporting excavated soil fluid using a foam inhibitor in the bubble shield method according to claim 1 . The junction pipe includes first, second, and third openings that communicate with each other.
The first opening is connected to a downstream end of the conveyor device;
The second opening is connected to a downstream end of a mud pipe that transfers the first mud water from an adjustment tank that stores the first mud water to the junction pipe,
The third opening is connected to an upstream end of a mud pipe that is provided with the mud pump and transfers the second mud water out of the tunnel from the merging pipe,
The cellular soil supplied to the first opening and the first mud supplied to the second opening are merged and mixed in the merge pipe to form the second mud. Mud is supplied to the drainage pipe from the third opening,
The fluid transport method for excavated soil using a foam suppressor in the bubble shield method according to claim 2 . The first mud water is water obtained by diluting muddy water from which the gravel and sand have been removed from the second mud water from which the gravel has been crushed, with fresh water from which fine particles have been removed from the mud from which the gravel and sand have been removed. is there,
The fluid transport method for excavated soil using a foam inhibitor in the bubble shield method according to any one of claims 1 to 3.

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