Foreign object protection device and foreign object protection method

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

[Technical Field]

[0001] The present invention relates to technology related to expandable gaskets installed inside the departure and arrival tunnel entrances of shield machines, and more specifically to a foreign object protection device that prevents foreign objects that would hinder the expansion of the expandable gasket from moving to the expandable gasket, and a foreign object protection method using the same. [Background technology]

[0002] The shield tunneling method involves digging underground with a shield machine while stabilizing the tunnel face, and then lining the tunnel with segments to build underground railway tunnels, road tunnels, water supply and sewerage tunnels, utility conduits, and tunnels for power and communications.

[0003] Since tunnels constructed using the shield method (hereinafter simply referred to as "shield tunnels") are planned to be located deeper than the ground surface, it is common for a departure shaft to be formed at the start of the shield tunnel for lowering the shield machine to the excavation depth, while a destination shaft to pull the shield machine up to the ground is formed at the end of the shield tunnel.

[0004] When excavating a shield tunnel, it is naturally necessary to install a shield machine at the excavation depth within the departure shaft (hereinafter referred to as the "departure shaft portal"). Typically, the shield machine is divided into sections and lowered from the ground and assembled at the departure shaft portal. Once the shield machine is assembled, it begins to excavate from the departure shaft portal into the natural ground, and as this excavation progresses, groundwater and earth and sand begin to flow into the departure shaft portal. If groundwater and earth and sand are allowed to flow into the departure shaft portal, there is a risk of the departure shaft being submerged, resulting in personal injury to workers, and there is also a risk of the natural ground collapsing, which could have a significant negative impact on the surrounding environment.

[0005] For this reason, packing is sometimes installed at the departure tunnel entrance, as shown in Figure 6. The packing is attached to the inner periphery of the ring-shaped tunnel entrance hardware installed at the departure tunnel entrance, and this packing closes the gap between the outer periphery of the shield machine (i.e., the skin plate) and the tunnel entrance hardware, thereby preventing groundwater and sediment from flowing into the departure tunnel entrance. However, the rotating part of the shield machine's cutter can sometimes interfere with this packing when it passes through it, so in these cases, an expandable packing is preferred.

[0006] Figure 7 is a step diagram that shows a schematic example of the operation of the expansion packing, and is an enlarged cross-sectional view of "Part A" shown in Figure 6. As shown in Figure 7(a), the expansion packing is initially positioned along the wellhead hardware, leaving a specified gap between the skin plate and the wellhead hardware. This allows the shield machine to advance toward the natural ground without the cutter rotating part interfering with the expansion packing. Once the cutter rotating part passes, the expansion packing expands as shown in Figure 7(b), closing the gap between the skin plate and the wellhead hardware. This prevents groundwater and soil generated during the shield machine's excavation from flowing into the starting tunnel.

[0007] When the cutter's rotating part passes the expansion packing, some excavation will occur, which means that a certain amount of excavated soil may flow into the departure shaft. In this case, gravel may be deposited at the departure shaft, especially around the expansion packing, and if the expansion packing expands in this state, the gap between the skin plate and the shaft opening hardware will not be closed sufficiently, as shown in Figure 8. With gravel trapped between the skin plate and the expansion packing in this state, groundwater will be allowed to flow in, and there is a risk that the departure shaft will be submerged, so this must be avoided for the safety of the workers.

[0008] Countermeasures against the problem of groundwater inflow into the departure shaft have been proposed in the past. For example, Patent Document 1 proposes a technology to prevent groundwater inflow by using wire brush packing attached to a ring-shaped steel plate in a cylindrical shaft. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Utility Model Registration No. 3190336 Summary of the Invention [Problem to be solved by the invention]

[0010] The technology disclosed in Patent Document 1 aims to prevent groundwater from entering a cylindrical shaft, and to solve this problem, a wire brush packing (or packing sealing tube) is configured to contact the outer periphery of the tunneling machine in a three-dimensional state. Naturally, the wire brush packing and packing sealing tube are designed to be watertight.

[0011] However, it is generally difficult to achieve watertightness using wire brushes alone. Patent Document 1 therefore states, "The wire brush packing 200 is filled with grease material 21 (paragraph

[0019] )." However, filling the wire brush packing 200 with grease material 21 to achieve watertightness requires a considerable amount of grease material 21 and the installation of a filling device, resulting in considerable cost and effort. Furthermore, if watertightness were to be achieved using wire brushes alone, it would require the use of special wire brushes, such as a structure in which the wire brushes are covered with a bag-like material or a structure in which the wires are arranged quite densely, which would also increase procurement costs. Furthermore, because the wire brushes contact the outer periphery of the tunneling machine in a three-dimensional manner, they would be installed around the entire circumference of the tunneling machine, which also requires considerable cost and effort for watertightness.

[0012] The object of the present invention is to solve the problems associated with the prior art, namely to provide a foreign object protection device that can suppress the obstruction of expansion of an expansion packing caused by foreign objects (such as gravel) that occur during excavation, at a lower cost than the prior art such as that shown in Patent Document 1, and a foreign object protection method using the same. [Means for solving the problem]

[0013] The present invention was made with a focus on the fact that it prevents the inflow of sand and gravel for only a short period of time until the expansion packing expands, and therefore utilizes a shield that allows groundwater to flow through but does not allow sand and gravel to pass through, and is an invention based on an unprecedented idea.

[0014] The foreign object protection device of the present invention is equipped with a shield to protect the expandable packing installed at the departure tunnel entrance (or arrival tunnel entrance) from foreign objects generated during excavation by the shield machine. This shield has the function of allowing water to pass through but not foreign objects. The foreign object protection device of the present invention is installed at the departure tunnel entrance (or arrival tunnel entrance) on the natural ground side of the expandable packing and so as to correspond to part (or all) of the outer periphery of the skin plate of the shield machine. In this way, the shield located between the cutter rotating part of the shield machine and the expandable packing can prevent the passage of foreign objects that would interfere with the expansion action of the expandable packing.

[0015] The foreign object protection device of the present invention may also be one that uses a brush-like shield formed of a plurality of wires.

[0016] The foreign object protection method of the present invention is a method for protecting an expandable packing installed at a starting tunnel entrance (or a destination tunnel entrance) from foreign objects generated during excavation by a shield machine using the foreign object protection device of the present invention, and is a method comprising a foreign object protection device installation step and an excavation step. In the foreign object protection device installation step, the foreign object protection device of the present invention is installed at the starting tunnel entrance (or the destination tunnel entrance) on the natural ground side of the expandable packing and so as to correspond to part (or all) of the outer periphery of the skin plate of the shield machine. On the other hand, in the excavation step, excavation is carried out using the shield machine from the starting tunnel entrance toward the natural ground (or from the natural ground to the destination tunnel entrance). [Effects of the Invention]

[0017] The foreign object protection device and method of the present invention have the following advantages. (1) The expansion packing is prevented from expanding by preventing the inflow of sand and gravel at least until the packing expands, which prevents the packing from being hindered from expanding. As a result, the packing expands sufficiently to close the gap between the skin plate and the tunnel head hardware, preventing groundwater and soil from flowing into the tunnel head during shield machine excavation, and preventing the start shaft from being submerged or the ground from collapsing. (2) Since it does not allow sand and gravel to pass through but allows groundwater to pass through, there is no need to procure special wire brushes, etc., and therefore it can be implemented at a lower cost than conventional technologies such as those shown in Patent Document 1. [Brief explanation of the drawings]

[0018] [Figure 1] A cross-sectional view schematically showing a situation in which a shield machine starts from a starting tunnel entrance where a foreign object protection device of the present invention is installed. [Figure 2] (a) is a cross-sectional view showing a schematic diagram of a foreign object protection device attached to the inner circumference of a ring-shaped wellhead metalwork, (b) is an enlarged front view showing a schematic diagram of a part of the foreign object protection device equipped with a shield, and (b) is an enlarged side view showing a schematic diagram of the shield of the foreign object protection device. [Figure 3]A cross-sectional view schematically showing a situation in which the expansion packing has expanded sufficiently to close the gap between the skin plate and the wellhead hardware due to the effect of the foreign object protection device of the present invention. [Figure 4] A cross-sectional view schematically showing a situation in which a shield machine enters an access tunnel portal where a foreign object protection device of the present invention is installed. [Figure 5] 1 is a flow chart showing the main steps of a foreign object protection method according to the present invention. [Figure 6] A cross-sectional view schematically showing the starting tunnel entrance where a packing is installed and the shield machine excavating into the natural ground. [Figure 7] FIG. 1( a ) is a step diagram schematically showing the state of the expandable packing before expansion, and FIG. 1( b ) is a step diagram schematically showing the state of the expandable packing after expansion. [Figure 8] FIG. 10 is a cross-sectional view schematically showing a state in which a foreign object is caught between the skin plate and the expansion packing. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the foreign object protection device and foreign object protection method of the present invention will be described with reference to the drawings.

[0020] 1.Overview The present invention protects the expandable packing from foreign objects (e.g., gravel) that may impede its expansion when the shield machine starts excavating from the starting tunnel (i.e., starting) or when it reaches the destination tunnel. More specifically, the object protection device of the present invention, located at the starting tunnel (or destination tunnel) closer to the natural ground than the expandable packing, blocks excavated soil (e.g., gravel) generated when the shield machine starts moving, preventing the excavated soil from moving toward the expandable packing until the expandable packing begins to expand, thereby enabling normal expansion. The object protection device of the present invention includes a shield that allows groundwater to pass through but prevents excavated soil from passing through. This prevents the inflow of sand and gravel until the expandable packing expands, without requiring excessively high performance.

[0021] 2.Foreign object protection device Next, the foreign object protection device of the present invention will be described in detail. The foreign object protection method of the present invention is a method for protecting an expandable packing from foreign objects using the foreign object protection device of the present invention. Therefore, the foreign object protection device of the present invention will be described first, and then the foreign object protection method of the present invention will be described.

[0022] 1 is a cross-sectional view showing a schematic diagram of a shield machine MC starting from a departure tunnel entrance where a foreign object protection device 100 of the present invention is installed. At the departure tunnel entrance (or arrival tunnel entrance) where the foreign object protection device 100 of the present invention is used, an expandable packing 200 is installed on the inner periphery of a ring-shaped tunnel entrance hardware 400. Of course, as shown in this figure, the foreign object protection device 100 of the present invention can also be used at a departure tunnel entrance (or arrival tunnel entrance) where a spare packing 300 is installed in addition to the expandable packing 200.

[0023] The foreign object protection device 100 is installed at the departure tunnel entrance (or arrival tunnel entrance) closer to the natural ground than the expandable packing 200. More specifically, as shown in Figure 2(a), it is attached to the inner periphery of a ring-shaped tunnel entrance hardware 400. In this figure, the foreign object protection device 100 is attached so as to correspond to the entire outer periphery of the skin plate of the shield machine MC, that is, around the entire circumference of the tunnel entrance hardware 400, but this is not limiting and the foreign object protection device 100 may also be attached so as to correspond to a portion of the outer periphery of the skin plate, that is, to a portion of the tunnel entrance hardware 400 (at one or more locations).

[0024] 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 including the shield 110, and FIG. 2(c) is an enlarged side view of the shield 110 of the foreign object protection device 100. As described above, the shield 110 has the function of blocking (shielding) excavated soil (hereinafter referred to as "foreign objects"), such as sand and gravel, generated during excavation by the shield machine MC, while allowing fluids (liquids, gases, etc.) such as groundwater to pass through. For example, FIG. 2 shows the shield 110 as a brush-like object (such as a wire brush) made of multiple wires. Alternatively, the shield 110 may be a mesh-like object (such as a wire mesh) or a scrubbing brush-like object (such as a metal scrubbing brush). However, it is desirable that the material be elastic enough to be easily deformed in response to the movement of the shield machine MC, and also be made of a material that has considerable strength.

[0025] As shown in FIG. 1, the foreign object protection device 100 is preferably installed so that the shield 110 is approximately perpendicular (including perpendicular) to the axial direction of the shield machine MC. In prior art, such as Patent Document 1, when wire brushes or the like are installed at the starting tunnel entrance, they are installed at an angle (i.e., lying down). For example, in Patent Document 1, as shown in FIG. 10, the tip of the wire brush packing is installed so as to gently tilt forward (in the direction of travel of the shield machine MC). This is because the wire brush packing in Patent Document 1 is designed not to interfere with the travel of the shield machine MC, and is also intended to provide watertightness and adhesion. In contrast, the foreign object protection device 100 (particularly the shield 110) of the present invention is designed to prevent the passage of foreign objects and allows the flow of groundwater and other debris, so watertightness and adhesion are not required. Therefore, there is no need to install the shield 110 at a gentle incline (i.e., lying down), nor is it necessary to place it in close contact with the shield machine MC (skin plate). That is, the shielding body 110 can be placed so as to be approximately perpendicular to the axial direction of the shield machine MC, and can also be installed with a specified gap (which is smaller than the size of the expected foreign object) between the tip of the shielding body 110 and the skin plate. By installing the shielding body 110 so as to be approximately perpendicular to the axial direction of the shield machine MC in this way, not only can it prevent the passage of flowing foreign objects, but it can also be expected to have the effect of sweeping away any adhering (sticky) foreign objects with the very tip of the brush.

[0026] In Figure 1, as the shield machine MC advances toward the natural ground, the expansion packing 200 is positioned along the wellhead hardware 400 (i.e., folded) so as not to interfere with the cutter rotating part CT, and a specified gap is created between the skin plate of the shield machine MC and the wellhead hardware 400. Meanwhile, the cutter rotating part CT has already advanced into the natural ground, meaning that a certain amount of foreign matter has entered the starting wellhead. However, because the shield 110 has the function of allowing groundwater and the like to pass through but not foreign matter, the shield 110 restricts the foreign matter from moving any further (to the left in the figure), preventing the foreign matter from reaching the position of the expansion packing 200.

[0027] In this way, foreign objects caused by excavation are blocked by the shield 110 of the foreign object protection device 100, so it is possible to avoid a situation where sand and gravel get caught between the skin plate and the expansion packing 200 (Fig. 8), and as shown in Fig. 3, the expansion packing 200 can expand sufficiently to close the gap between the skin plate and the wellhead hardware 400. As a result, it is possible to suppress the inflow of groundwater and earth and sand into the starting wellhead during excavation by the shield machine MC, and it is possible to avoid the submersion of the starting shaft and the collapse of the ground.

[0028] While the above description focuses on an example in which the shield machine MC departs from the departure tunnel, the foreign object protection device 100 of the present invention can also be used when the shield machine MC reaches a destination tunnel. In Figure 4, when the shield machine MC enters the destination tunnel from the natural ground, the expansion packing 200 is folded to prevent interference with the cutter rotating part CT, creating a predetermined gap between the skin plate of the shield machine MC and the tunnel head hardware 400. Meanwhile, the shield machine MC advances through the destination tunnel head with a portion of itself (on the left side in the figure) remaining in the natural ground, meaning that a certain amount of foreign object is drawn into the destination tunnel head. However, because the shield 110 allows groundwater and other impurities to pass through but not foreign objects, the shield 110 restricts further movement of the foreign object (to the right in the figure), preventing it from reaching the location of the expansion packing 200. This allows the expansion packing 200 to expand sufficiently to close the gap between the skin plate and the tunnel head hardware 400.

[0029] 3.Foreign object protection method Next, the foreign object protection method of the present invention will be described. The foreign object protection method of the present invention is a method for protecting an expandable packing from foreign objects using the foreign object protection device 100 described up to this point. Therefore, we will avoid overlapping explanations with those described for the foreign object protection device 100 and will only describe the details unique to the foreign object protection method of the present invention. In other words, the details not described here are the same as those described in "2. Foreign object protection device."

[0030] As described above, the foreign object protection device 100 of the present invention can be used when the shield machine MC starts from a starting tunnel portal, and can also be used when the shield machine MC reaches a destination tunnel portal. Similarly, the foreign object protection method of the present invention can be implemented when the shield machine MC starts from a starting tunnel portal, and when the shield machine MC reaches a destination tunnel portal. For convenience, the following description will be given using an example in which the shield machine MC starts from a starting tunnel portal.

[0031] FIG. 5 is a flow chart showing the main steps of the foreign object protection method of the present invention. As shown in this figure, first, a starting shaft is formed (Step 10 in FIG. 5), and then a wellhead hardware 400 is installed at the starting shaft entrance (Step 20 in FIG. 5). Next, the foreign object protection device 100 of the present invention is attached to the inner periphery of the wellhead hardware 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 periphery of the skin plate of the shield machine MC (i.e., the entire circumference of the wellhead hardware 400), or it can be attached so as to correspond to only a portion of the outer periphery of the skin plate (i.e., a portion of the wellhead hardware 400). In addition, an expandable packing 200 and a spare packing 300 are also installed in predetermined positions on the inner periphery of the wellhead hardware 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 (i.e., folded).

[0032] The shield machine MC, separated from the ground, is lowered into the departure shaft and assembled at the departure shaft entrance (Step 50 in Figure 5). Once assembly is complete, the shield machine MC is moved toward the natural ground (Step 60 in Figure 5). Furthermore, as the cutter rotating part CT passes through the expansion packing 200 and spare packing 300, the expansion packing 200 and spare packing 300 are expanded (Step 70 in Figure 5). As shown in Figure 1, as the shield machine MC moves, the cutter rotating part CT penetrates the natural ground, and a certain amount of foreign matter flows into the departure shaft entrance. However, because the shield 110 has the function of allowing groundwater and other substances to pass through but not foreign matter, the shield 110 restricts the further movement of the foreign matter. This prevents gravel from becoming trapped between the skin plate and the expansion packing 200 (Figure 8). As shown in Figure 3, the expansion packing 200 expands sufficiently to close the gap between the skin plate and the shaft entrance hardware 400.

[0033] Once the gap between the skin plate and the wellhead metal fitting 400 is closed, full-scale excavation is carried out using the shield machine MC while maintaining this state (Step 80 in Figure 5). [Industrial Applicability]

[0034] The foreign object protection device and method of the present invention can be used in the construction of underground road tunnels, as well as railway tunnels, water and sewer tunnels, utility conduits, and tunnels for power and communications. They can also be used for excavation using small- to large-diameter shield machines, or for slurry shield tunneling and earth pressure shield tunneling, and can be used in a wide range of soil types. Considering that the present invention enables the safe construction of social infrastructure such as tunnel structures, it can be said to be an invention that can be used not only industrially but also has the potential to make a significant contribution to society. [Explanation of symbols]

[0035] 100 Foreign object protection device of the present invention 110 (Foreign object protection device) shield 200 Expandable Packing 300 Spare packing 400 Minehead fittings CT cutter rotating part MC shield machine

Claims

1. A foreign object protection device that protects an expandable packing installed at a starting tunnel entrance or an arrival tunnel entrance from foreign objects generated by excavation by a shield machine, a shield that allows water to pass through but does not allow the foreign matter to pass through; It is installed at the departure tunnel entrance or the arrival tunnel entrance on the natural ground side of the expandable packing so as to correspond to part or all of the outer periphery of the skin plate of the shield machine, the shielding body is installed in a position perpendicular or substantially perpendicular to the axial direction of the shield machine, with a predetermined gap being generated between the tip of the shielding body and the skin plate, The shielding body located between the cutter rotating part of the shield machine and the expandable packing prevents the passage of the foreign matter that interferes with the expansion action of the expandable packing. A foreign object protection device characterized by:

2. A method for protecting an expandable packing installed at a starting tunnel entrance or a destination tunnel entrance from foreign objects generated during excavation by a shield machine using a foreign object protection device, a foreign object protection device installation process for installing the foreign object protection device at the departure tunnel entrance or the arrival tunnel entrance on the natural ground side of the expandable packing so as to correspond to a part or all of the outer periphery of the skin plate of the shield machine; An excavation process in which excavation is performed by the shield machine from the starting tunnel entrance toward the natural ground or from the natural ground toward the arrival tunnel entrance, The foreign object protection device has a shield that allows water to pass through but does not allow the foreign object to pass through; the shielding body is installed in a position perpendicular or substantially perpendicular to the axial direction of the shield machine, with a predetermined gap being generated between the tip of the shielding body and the skin plate, In the excavation step, the shielding body located between the cutter rotating part of the shield machine and the expandable packing prevents the passage of the foreign matter that hinders the expansion action of the expandable packing. A method for protecting against foreign objects.

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