JP2022121822A - Foreign object protection device and foreign object protection method - Google Patents

Abstract

To solve problems with a conventional technique, in other words, to provide a foreign object protection device capable of suppressing expansion inhibition of an expandable packing due to foreign objects (such as sand and gravel) accompanying excavation at a lower cost than the conventional technique disclosed in patent document 1, and a foreign object protection method using thereof.SOLUTION: A foreign object protection device of the present invention protects an expandable packing installed at a starting wellhead from foreign object generated accompanying excavation by a shield machine, and includes a shield. The shield has a function of allowing water to flow through but preventing foreign object from passing through. The foreign object protection device of the present invention is installed at the starting wellhead, and the shield between a rotary cutter of the shield machine and the expandable packing prevents the passage of foreign objects that may hinder the expanding action of the expandable packing.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technology related to an expandable packing installed in the start portal and the arrival portal of a shield machine. The present invention relates to a device and a foreign matter protection method using the same.

In the shield tunneling method, a shield machine is used to excavate the ground while stabilizing the tunnel face, and lining is performed with segments to create underground railway tunnels, road tunnels, tunnels for water supply and sewerage, utility tunnels, and tunnels for electric power communication. etc.

Tunnels constructed by the shield construction method (hereafter simply referred to as "shield tunnels") are planned at a position deeper than the ground surface. is formed, and on the other hand, an arrival shaft is generally formed on the terminal side of the shield tunnel for pulling up the shield machine to the ground.

When excavating a shield tunnel, of course, it is necessary to install a shield machine at the excavation depth in the starting shaft (hereinafter referred to as "starting tunnel"), and normally divided shield machines are suspended from the ground. are assembled at the launch wellhead. When the shield machine is assembled, it excavates from the starting pit toward the natural ground, but groundwater and earth and sand flow into the starting pit along with this excavation. If groundwater and sediment are allowed to flow into the starting shaft, the starting shaft may be submerged, resulting in human disasters for workers. be.

Therefore, as shown in FIG. 6, a packing may be installed at the starting wellhead. A packing is attached to the inner peripheral side of the ring-shaped wellhead hardware provided at the starting wellhead, and this packing closes the gap between the outer circumference of the shield machine (that is, the skin plate) and the wellhead hardware, thereby preventing groundwater and It prevents the inflow of earth and sand. However, when the rotating part of the cutter of the shield machine passes through the packing, it may interfere with this packing, and in this case, the expandable packing is preferably used.

FIG. 7 is a step diagram schematically showing an example of the operation of the expandable packing, and is an enlarged cross-sectional view of "A section" shown in FIG. As shown in FIG. 7(a), the expansion packing is initially positioned along the wellhead fitting, and a predetermined gap is created between the skin plate and the wellhead fitting. As a result, the shield machine can move forward toward the natural ground without the rotating portion of the cutter interfering with the expansion packing. When the cutter rotating part passes through, the expansion packing expands as shown in FIG. 7(b) to close the gap between the skin plate and the wellhead fitting. As a result, it is possible to prevent groundwater and earth and sand generated during excavation by the shield machine from flowing into the starting portal.

When the cutter rotating part passes through the expansion packing, some excavation is performed, that is, excavated earth and sand may flow into the starting wellhead to some extent. In this case, gravel and the like may be deposited at the starting wellhead, especially around the expansion packing, and if the expansion packing expands from this state, the gap between the skin plate and the wellhead metal fittings will not be sufficiently closed, as shown in Fig. 8. becomes. In this way, if gravel is caught between the skin plate and the expansion packing, groundwater will be allowed to flow in, and the starting shaft may be submerged, so it must be avoided from the safety of workers.

Until now, countermeasures have been shown to deal with the inflow of groundwater into the starting vertical shaft. We are proposing a technology to prevent this.

Utility Model Registration No. 3190336

The technology disclosed in Patent Document 1 aims at preventing the intrusion of groundwater into a cylindrical vertical shaft. It is configured to contact. And, of course, the wire brush packing and the packing sealing tube have a structure capable of stopping water.

By the way, it is usually difficult to think of stopping water only with a wire brush. Therefore, Patent Document 1 also states that "the wire brush packing 200 is filled with the grease material 21 (paragraph number [0019])". However, in order to fill the wire brush packing 200 with the grease material 21 to achieve the water stop function, a considerable amount of the grease material 21 is required and a filling device must be installed. Considerable cost and effort will be required for water. Also, if water is stopped only by wire brushes, it is possible to use a special wire brush, such as a structure that covers the wire brush with a bag-like material, or a structure in which the wires are arranged quite densely. It is considered, and the procurement cost will be pushed up. Furthermore, since the wire brush comes into contact with the outer circumference of the excavation machine in a three-dimensional state, the wire brush must be installed over the entire circumference of the excavation machine.

An object of the present invention is to solve the problems of the prior art, that is, to prevent the expansion of the expansion packing from being hindered by foreign matter (gravel, etc.) accompanying excavation at a lower cost than the prior art disclosed in Patent Document 1. It is an object of the present invention to provide a foreign matter protection device capable of suppressing foreign matter and a foreign matter protection method using the same.

The invention of the present application is intended to prevent the inflow of gravel and the like only for a short period of time until the expansion packing expands. It is an invention made based on an unprecedented idea.

The foreign matter protection device of the present invention protects an expandable packing installed at a starting portal (or an arrival portal) from foreign matter generated during excavation by a shield machine, and includes a shield. This shield has a function of allowing water to flow through but preventing foreign matter from passing through. The foreign object protection device of the present invention is installed at the starting portal (or reaching portal) so as to correspond to a part (or the whole) of the outer periphery of the skin plate of the shield machine on the ground side of the expandable packing. As a result, the shield between the rotating cutter portion of the shield machine and the expandable packing can prevent the passage of foreign matter that would hinder the expanding action of the expandable packing.

The foreign object protection device of the present invention can also use a brush-like shield formed of a plurality of wire rods.

A foreign matter protection method of the present invention is a method of protecting an expandable packing installed at a starting portal (or an arrival portal) from foreign matter generated during excavation by a shield machine using the foreign matter protection device of the present invention, comprising: This method includes a step of installing a foreign object protection device and a step of excavating. Among these steps, in the process of installing the foreign matter protection device, the foreign matter protection device of the present invention is installed at the starting portal (or reaching portal) so as to correspond to a portion (or the entirety) of the outer periphery of the skin plate of the shield machine, which is closer to the natural ground than the expandable packing. ). On the other hand, in the excavation process, excavation is performed by a shield machine from the starting tunnel toward the rock (or from the rock to the arrival tunnel).

The foreign object protecting device and the foreign object protecting method of the present invention have the following effects.
(1) Since the inflow of gravel and the like is prevented at least until the expansion packing expands, it is possible to suppress the expansion inhibition of the expansion packing. As a result, the expansion packing expands sufficiently to close the gap between the skin plate and the wellhead hardware, and during excavation of the shield machine, it is possible to suppress the inflow of groundwater and sediment into the starting shaft. You can avoid the collapse of mountains.
(2) It does not allow sand and gravel to pass through, but allows groundwater to flow through, so there is no need to procure a special wire brush or the like. can be done.

FIG. 3 is a cross-sectional view schematically showing a state in which a shield machine starts from a starting portal in which the foreign object protection device of the present invention is installed; (a) is a cross-sectional view schematically showing a foreign matter protection device attached to the inner periphery of a ring-shaped wellhead metal fitting, and (b) is an enlarged front view schematically showing a part of the foreign matter protection device provided with a shield. , (b) is an enlarged side view schematically showing the shield of the foreign object protection device; FIG. 4 is a cross-sectional view schematically showing a state in which the expansion packing is sufficiently expanded to close the gap between the skin plate and the wellhead fitting due to the effects of the foreign object protection device of the present invention; FIG. 4 is a cross-sectional view schematically showing a state in which a shield machine enters a portal in which the foreign matter protection device of the present invention is installed; FIG. 2 is a flowchart showing main steps of the foreign matter protection method of the present invention; FIG. 2 is a cross-sectional view schematically showing a starting wellhead in which a packing is installed and a shield machine that excavates into the natural ground; (a) is a step diagram schematically showing a state before the expandable packing is expanded, and (b) is a step diagram schematically showing the state after the expandable packing is expanded. FIG. 4 is a cross-sectional view schematically showing a state in which a foreign object is sandwiched between the skin plate and the expansion packing;

An embodiment of the foreign object protecting device and the foreign object protecting method of the present invention will be described with reference to the drawings.

1. Overall overview The present invention is to prevent foreign matter (e.g., gravel, etc.) that hinders the expansion of the expandable packing when the shield machine starts digging from the starting tunnel (that is, starts) or reaches the arrival tunnel. protection. More specifically, the foreign object protection device of the present invention, which is the starting portal (or the reaching portal) and is located closer to the natural ground than the expandable packing, operates until the expansion of the expandable packing starts, as the shield machine starts. This invention was devised for the purpose of blocking excavated earth and sand (for example, gravel, etc.), that is, preventing excavated earth and sand from moving to the expandable packing, thereby enabling normal expansion operation. The foreign matter protection device of the present invention has a shield, and this shield has the function of allowing groundwater to flow through but not excavated earth and sand. As a result, the foreign object protection device of the present invention can prevent the inflow of gravel or the like until the expansion packing expands without requiring excessively high functionality.

2. Foreign Matter Protection Device Next, the foreign matter protection device of the present invention will be described in detail. It should be noted that the foreign matter protection method of the present invention is a method of protecting an expandable packing from foreign matter using the foreign matter protection device of the present invention. Therefore, first, the foreign matter protecting device of the present invention will be described, and then the foreign matter protecting method of the present invention will be described.

FIG. 1 is a cross-sectional view schematically showing a state in which a shield machine MC starts from a starting wellhead in which a foreign object protection device 100 of the present invention is installed. An expandable packing 200 is installed on the inner peripheral side of a ring-shaped wellhead fitting 400 at a starting wellhead (or a reaching wellhead) where the foreign object protection device 100 of the present invention is used. Of course, as shown in this figure, the foreign object protection device 100 of the present invention can also be used in a starting wellhead (or a reaching wellhead) in which a spare packing 300 is installed in addition to the expandable packing 200 .

The foreign object protection device 100 is installed at the starting portal (or reaching portal) and closer to the ground than the expandable packing 200 is. More specifically, as shown in FIG. 2( a ), it is attached to the inner peripheral side of the ring-shaped wellhead metal fitting 400 . In this figure, the foreign object protection device 100 is attached so as to correspond to the entire outer circumference of the skin plate of the shield machine MC, that is, over the entire circumference of the wellhead hardware 400, but it is not limited to this, and is part of the outer circumference of the skin plate. , that is, the foreign object protection device 100 may be attached partially (at one or more locations) of the wellhead hardware 400 .

The foreign object protection device 100 also includes a shield 110 as shown in FIGS. 2(b) and 2(c). FIG. 2(b) is an enlarged front view of a portion of the foreign object protection device 100 having the shield 110, and FIG. 2(c) is an enlarged view of the shield 110 of the foreign object protection device 100 seen from the side. It is a diagram. As described above, the shield 110 has a function of blocking excavated soil such as sand and gravel (hereinafter referred to as "foreign matter" for convenience) generated during excavation by the shield machine MC (to be able to shield), and also has a function of blocking groundwater and the like. It has the function of allowing fluid (liquid, gas, etc.) to flow through. For example, FIG. 2 shows a brush-like object (such as a wire brush) formed of a plurality of wires as the shield 110 . In addition, as the shield 110, a mesh-like one (wire netting, etc.) or a scourer-like one (metal scourer, etc.) can be used. However, it is desirable to use a material that has elasticity and considerable strength so that it can be easily deformed according to the movement of the shield machine MC.

As shown in FIG. 1, the foreign object protection device 100 should be installed so that the shield 110 is substantially perpendicular (including perpendicular) to the axial direction of the shield machine MC. In the prior art including Patent Literature 1, when a wire brush or the like is installed in the starting portal, it is installed so that its posture is in an oblique direction (that is, it is laid down). For example, in the case of Patent Literature 1, as shown in FIG. 10, the tip side of the wire brush packing is installed so as to gently incline forward (in the traveling direction of the shield machine MC). This is because the wire brush packing of Patent Literature 1 is designed so as not to hinder the progress of the shield machine MC, and is intended for waterproofing and adhesion. On the other hand, the foreign matter protection device 100 (particularly, the shield 110) of the present invention is intended to prevent the passage of foreign matter, and allows the flow of groundwater or the like. Not asked. Therefore, it is not necessary to arrange the shield 110 with a gentle slope (that is, lay it down), and it is not necessary to bring it into close contact with the shield machine MC (skin plate). That is, the shield 110 can be arranged so as to be substantially perpendicular to the axial direction of the shield machine MC, and a predetermined gap (however, the expected foreign matter It can also be installed with a gap of less than the size of . When the shield 110 is installed so as to be substantially perpendicular to the axial direction of the shield machine MC in this way, not only does it prevent the passage of foreign matter that flows, but it also sweeps away adhering (sticky) foreign matter with the tip of the brush. You can also expect the effect of taking.

In FIG. 1, when the shield machine MC advances toward the ground, the expansion packing 200 is positioned (that is, folded) along the wellhead hardware 400 so as not to interfere with the cutter rotating part CT. A predetermined gap is generated between the skin plate and the wellhead metal fitting 400 . On the other hand, the rotating cutter part CT has already entered the ground, that is, a certain amount of foreign matter has flowed into the starting pit. However, since the shield 110 has a function of allowing groundwater to flow through but preventing foreign matter from passing through, the shield 110 restricts further movement of the foreign matter (movement to the left in the figure). It prevents foreign matter from reaching the position.

In this way, since the shield 110 of the foreign object protection device 100 blocks foreign objects accompanying excavation, it is possible to avoid the state in which gravel is caught between the skin plate and the expansion packing 200 (FIG. 8). The expansion packing 200 can be expanded sufficiently to close the gap between the skin plate and the wellhead fitting 400, as shown in FIG. As a result, during excavation by the shield machine MC, it is possible to suppress the inflow of groundwater and earth and sand into the starting shaft, thereby avoiding submersion of the starting shaft and collapse of the natural ground.

Although an example in which the shield machine MC starts from the starting portal has been described so far, the foreign object protective device 100 of the present invention can also be used in cases where the shield machine MC reaches the arrival portal. In FIG. 4, the expansion packing 200 is folded so as not to interfere with the cutter rotating part CT when the shield machine MC enters the arrival tunnel from the ground side. has a predetermined gap. On the other hand, the shield machine MC advances through the arrival pit with a part (left side in the drawing) remaining in the ground, that is, a certain amount of foreign matter is drawn into the arrival pit. However, since the shield 110 has a function of allowing groundwater to flow through but preventing foreign matter from passing through, the shield 110 restricts further movement of the foreign matter (movement to the right in the figure), that is, the expansion packing 200 It prevents foreign matter from reaching the position. Thereby, the expansion packing 200 can be expanded sufficiently to close the gap between the skin plate and the wellhead fitting 400 .

3. Foreign Matter Protection Method Next, the foreign matter protection method of the present invention will be described. It should be noted that the method for protecting an expandable packing according to the present invention is a method for protecting an expandable packing from foreign matter using the foreign matter protecting device 100 described above. Therefore, descriptions that overlap with the description of the foreign object protecting device 100 will be avoided, and only specific contents of the foreign object protecting method of the present invention will be described. That is, the contents not described here are the same as those described in "2. Foreign matter protection device".

As described above, the foreign matter protecting device 100 of the present invention can be used in the case where the shield machine MC starts from the starting portal, and can also be used in the case where the shield machine MC reaches the arrival portal. Similarly, the foreign object protection method of the present invention can also be implemented in the case where the shield machine MC starts from the starting portal or the case where the shield machine MC reaches the arrival portal. For the sake of convenience, an example in which the shield machine MC starts from the starting portal will be described here.

FIG. 5 is a flowchart showing the main steps of the foreign matter protection method of the present invention. As shown in this figure, first, a starting shaft is formed (Step 10 in FIG. 5), and a wellhead metal fitting 400 is installed in the starting shaft (Step 20 in FIG. 5). Then, the foreign object protection device 100 of the present invention is attached to the inner peripheral side of the wellhead metal fitting 400 (Step 30 in FIG. 5). At this time, the foreign object protection device 100 can be attached so as to correspond to the entire outer circumference of the skin plate of the shield machine MC (that is, over the entire circumference of the wellhead metal fitting 400), or to correspond to a part of the outer circumference of the skin plate. (that is, partially in the wellhead hardware 400). Also, the expandable packing 200 and the spare packing 300 are installed at predetermined positions on the inner peripheral side of the wellhead metal fitting 400 (Step 40 in FIG. 5). However, at this point, the expandable packing 200 and the spare packing 300 are positioned along the wellhead hardware 400 (that is, folded).

The divided shield machines MC are suspended from the ground in the starting shaft, and the shield machines MC are assembled at the starting shaft (Step 50 in FIG. 5). When the assembly is completed, the shield machine MC is moved to the ground (Step 60 in FIG. 5), and when the rotating cutter CT passes through the expandable packing 200 and the spare packing 300, the expandable packing 200 and the spare packing 300 are expanded. (Step 70 in FIG. 5). As shown in FIG. 1, as the shield machine MC moves, the rotating cutter CT enters into the ground, and a certain amount of foreign matter flows into the starting portal, but the shield 110 allows groundwater and the like to flow through. Since the shield 110 has a function of not allowing foreign matter to pass through, the shield 110 restricts further movement of the foreign matter. As a result, the state (FIG. 8) in which gravel is caught between the skin plate and the expansion packing 200 can be avoided, and as shown in FIG. You can close the gap between

When the gap between the skin plate and the wellhead metal fitting 400 is closed, full-scale excavation by the shield machine MC is carried out while maintaining this state (Step 80 in FIG. 5).

The foreign matter protection device and foreign matter protection method of the present invention can be used in construction of underground road tunnels, railway tunnels, tunnels for water supply and sewerage, utility tunnels, and tunnels for electric power communication. In addition, it can be used for excavation by small to large diameter shield machines, slurry shield construction method and earth pressure shield construction method, and can be used for a wide range of soil types. Considering that it is possible to safely construct a social infrastructure (social infrastructure) such as a tunnel structure according to the invention of the present application, it can be said that the invention can be expected to make a great contribution not only to industrial applications but also to society.

REFERENCE SIGNS LIST 100 foreign matter protection device of the present invention 110 shield (of foreign matter protection device) 200 expandable packing 300 spare packing 400 wellhead metal CT cutter rotating part MC shield machine

Claims (3)

A foreign matter protection device that protects an expandable packing installed at a starting portal or a reaching portal from foreign matter generated during excavation of a shield machine,
a shield that allows water to flow through but prevents said foreign matter from passing;
Installed at the start portal or the arrival portal so as to correspond to part or all of the outer circumference of the skin plate of the shield machine on the ground side from the expandable packing,
The shield between the cutter rotating part of the shield machine and the expandable packing prevents passage of the foreign matter that hinders the expanding action of the expandable packing,
A foreign object protection device characterized by: wherein the shield is brush-shaped and formed of a plurality of wires;
2. A foreign object protecting device according to claim 1, characterized in that: A method for protecting an expandable packing installed at a start portal or an arrival portal from foreign matter generated during excavation of a shield machine by a foreign matter protection device, comprising:
a step of installing a foreign object protection device in the starting portal or the arrival portal so as to correspond to part or all of the outer periphery of the skin plate of the shield machine on the ground side of the expandable packing; ,
an excavation step of excavating with the shield machine from the starting tunnel toward the natural ground or from the natural rock toward the arrival tunnel,
The foreign matter protection device has a shield that allows water to flow through but does not allow the foreign matter to pass through,
In the excavation step, the shield between the rotating cutter of the shield machine and the expandable packing prevents passage of the foreign matter that hinders the expanding action of the expandable packing.
A foreign matter protection method characterized by:

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