Shield excavator

Abstract

To provide a shield excavator that can accurately detect properties and condition of natural ground.SOLUTION: A shield excavator 1 comprises a rotary-type cutter 3, a cylindrical skin plate 2 that is provided at the rear of the cutter 3 and has a chamber 2a where sediment excavated by cutter 3 is retained therein, and a density meter 40 for detecting a sediment density of natural ground G and a moisture meter 50 for detecting a moisture content containing in the sediment of the natural ground G. The density meter 40 and the moisture meter 50 are provided to protrude from apertures 2b, 2c provided at an outer peripheral surface of the skin plate 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a shield tunneling machine. [Background technology]

[0002] Patent document 1 discloses a shield tunneling machine in which a face collapse detection device having a gamma ray source and a scintillation detector is installed in an opening formed on the outer surface of the skin plate in order to detect the properties of the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 5-46435 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the shield machine disclosed in Patent Document 1, the face collapse detection device is installed flush with the outer surface of the skin plate. As a result, the shield machine disclosed in Patent Document 1 detects not only the nature of the ground but also the properties of the soil in the overexcavation area, which may prevent accurate detection of the nature of the ground.

[0005] An object of the present invention is to provide a shield machine that can accurately detect the properties of the natural ground. [Means for solving the problem]

[0006] The present invention is a shield tunneling machine comprising a rotary cutter, a cylindrical skin plate provided behind the cutter and having a chamber inside in which soil excavated by the cutter is retained, and a detector for detecting at least one of the density of the soil in the ground and the moisture contained in the soil in the ground, the detector being arranged to protrude from an opening provided on the outer surface of the skin plate. [Effects of the Invention]

[0007] According to the present invention, the detector is provided so as to protrude from the opening provided on the outer peripheral surface of the skin plate, so that the detector can be brought closer to the natural ground, thereby enabling the properties of the natural ground to be detected accurately. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a shield machine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of a cutter head of a shield tunneling machine according to an embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view of the axial structure of the density meter and moisture meter according to the embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is an enlarged view of a density meter according to an embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view of the axial structure of a density meter and a moisture meter according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a shield machine 1 according to an embodiment of the present invention will be described with reference to the drawings.

[0010] As shown in Figure 1, a shield machine 1 excavates underground (natural ground G) to form a borehole, and then constructs a shield tunnel T (tunnel) by assembling segment rings 9, which will be described later, to cover the inner wall W1 of the borehole. In the following description, the face side, which is the direction in which the shield machine 1 advances, is referred to as the "front," and the tunnel entrance side, which is the opposite direction, is referred to as the "rear."

[0011] First, the overall configuration of a shield machine 1 will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view showing the schematic configuration of the shield machine 1, and Figure 2 is a view of the shield machine 1 as seen from the front of Figure 1, and is a front view of a cutter head 3.

[0012] A shield machine 1 of this embodiment is used, for example, in an air bubble shield method. As shown in Fig. 1, the shield machine 1 comprises a cylindrical skin plate 2 capable of supporting the inner wall W1 of the natural ground G, a rotary cutter head 3 (cutter) attached to the skin plate 2, and a partition wall 4 provided inside the skin plate 2 and dividing the interior of the skin plate 2 in the front-to-rear direction. Inside the skin plate 2, segment rings 9 are constructed one after another as the shield machine 1 advances. Note that the cross-sectional shape of the skin plate 2 is not limited to being circular, and may be elliptical or rectangular.

[0013] The skin plate 2 is provided behind the cutter head 3. A jack 5 is fixed to the rear of the partition wall 4 on the inner wall of the skin plate 2. The jack 5 receives a reaction force from the segment ring 9 and propels the skin plate 2 forward, pressing the cutter head 3 against the ground G. When the skin plate 2 is propelled and the segment ring 9 comes out of the skin plate 2, a backfill material (not shown) is filled between the outer peripheral surface of the segment ring 9 and the inner wall W1 of the ground G.

[0014] The cutter head 3 is a disk-shaped structure having an outer diameter slightly larger than that of the skin plate 2. As shown in Fig. 2, the cutter head 3 has hollow spoke portions 31 extending radially from the rotation axis C1 as the center, an annular ring portion 32 to which the tip ends of the spoke portions 31 are connected, openings 33 formed between adjacent spoke portions 31, and a plurality of cutter bits 34, 35 arranged at predetermined intervals in the circumferential and radial directions on the surfaces of the spoke portions 31 facing the excavation face (cutting face).

[0015] As shown in Figure 1, the cutter head 3 is connected to a motor 6 via a cutter shaft 6a and a reduction mechanism 6b, and is driven to rotate in front of the skin plate 2 by the drive of the motor 6. When the cutter head 3 rotates while pressed against the ground G, the ground G is excavated by the cutter bits 34, 35.

[0016] A chamber 2a is formed between the cutter head 3 and the partition wall 4. Earth and sand generated by excavation by the cutter head 3 (hereinafter referred to as "excavated earth and sand") is introduced into the chamber 2a through an opening 33 (see FIG. 2) provided in the cutter head 3.

[0017] A stirring rod (not shown) protruding into the chamber 2a is provided on each spoke 31 of the cutter head 3. As the cutter head 3 rotates, the stirring rod stirs the soil and sand remaining in the chamber 2a.

[0018] The partition wall 4 is provided with a resistivity meter (not shown) for detecting the resistivity of the excavated soil and sand in the chamber 2a, an earth pressure meter (not shown), and the like.

[0019] In addition, the partition 4 is provided with a screw conveyor 7 for discharging the soil and sand in the chamber 2a to the rear of the partition 4, and a plurality of fixed blades (not shown) that protrude into the chamber 2a to agitate the soil and sand that has accumulated in the chamber 2a.

[0020] In the shield machine 1, by filling the chamber 2a with earth and sand and generating earth pressure (earth pressure) in the chamber 2a, the earth pressure and groundwater pressure at the tunnel face can be suppressed and the tunnel face can be stabilized. The earth pressure in the chamber 2a is adjusted by controlling the amount of earth and sand discharged from the chamber 2a using the screw conveyor 7, or by controlling the excavation speed of the shield machine 1. The earth pressure in the chamber 2a can also be adjusted by injecting, for example, an aqueous solution (liquid) containing a mud-adding agent into the earth and sand in the chamber 2a.

[0021] As shown in Figure 1, the shield machine 1 further includes an air bubble injection pipe 10 that injects air bubbles into the tunnel face in order to increase the fluidity of the excavated soil. One end of the air bubble injection pipe 10 is connected to an air bubble supply device (not shown) such as a pump, and the other end opens to the front of the cutter head 3.

[0022] The shield tunneling machine 1 excavates while injecting shaving cream-like foam, obtained by foaming a foaming agent in an air foam supply device, into the tunnel face. The foam injected into the tunnel face improves the fluidity and water-stopping properties of the excavated soil and prevents the soil from adhering to the chamber 2a. This allows for smooth excavation while maintaining the stability of the tunnel face. For example, an anionic surfactant is used as the foaming agent. Alternatively, the foam may be injected into the chamber 2a.

[0023] The shield machine 1 configured in this way rotates the cutter head 3 to excavate the natural ground G, while extending the jacks 5 to advance through the natural ground G. A borehole is excavated in the natural ground G, and the segment rings 9 are successively assembled along the inner circumferential surface of the borehole to construct the shield tunnel T. By injecting backfill material into the gaps that form between the inner circumferential surface of the borehole and the outer circumferential surfaces of the segment rings 9, the segment rings 9 become firmly bonded to the natural ground G via the backfill material.

[0024] As shown in Figure 1, the shield tunneling machine 1 further includes a density meter 40 (detector) for detecting the density of the soil in the ground G, and a moisture meter 50 (detector) for detecting the moisture contained in the soil in the ground G.

[0025] The density meter 40 and moisture meter 50 are attached to the outer peripheral surface of the skin plate 2 of the shield machine 1 and detect the density and moisture amount (water content) of the ground G. In this embodiment, the density meter 40 and moisture meter 50 are arranged side by side in the front-to-rear direction of the shield machine 1. Specifically, as shown in FIG. 3, openings 2b and 2c are formed in the outer peripheral surface of the skin plate 2, penetrating the skin plate 2 and arranged side by side in the front-to-rear direction of the shield machine 1. In this embodiment, the openings 2b and 2c are provided near the circumferential top of the skin plate 2 (see FIG. 1, etc.). The density meter 40 and moisture meter 50 are fixed to the skin plate 2 so as to protrude from the openings 2b and 2c, respectively.

[0026] In this embodiment, a scattering-type density meter is used as the density meter 40. As shown in Figures 3 to 5, the density meter 40 includes a radiation source unit 40a that irradiates gamma rays toward the natural ground G, radiation detection units 40b and 40c that detect reflected and scattered gamma rays irradiated from the radiation source unit 40a, and a support unit 40e that supports the radiation source unit 40a and the radiation detection units 40b and 40c and is fixed to the skin plate 2.

[0027] The radiation source unit 40a irradiates gamma rays using a sealed RI radiation source such as cesium, cobalt, or barium. The radiation source unit 40a and the radiation detection units 40b and 40c are arranged to be spaced apart in the front-to-back direction of the skin plate 2. The radiation source unit 40a and the radiation detection units 40b and 40c are arranged so that the distance D1 between the radiation source unit 40a and the radiation detection unit 40b and the distance D2 between the radiation source unit 40a and the radiation detection unit 40c are different lengths. This makes it possible to determine whether the attenuation of the gamma rays emitted from the radiation source unit 40a is due to distance or density.

[0028] The density meter 40 detects gamma rays emitted from the radiation source unit 40a toward the ground G and reflected and scattered by the soil and sand in the ground G, and calculates the wet density of the soil and sand in the ground G based on the amount of attenuation in the soil and sand.

[0029] The density data of the excavated soil measured by the density meter 40 is transmitted to the controller 60 (see FIG. 3).

[0030] 3 and 6, the moisture meter 50 includes a radiation source unit 50a that emits fast neutrons from a neutron source toward the natural ground G, a thermal neutron detection unit 50b that detects thermal neutrons that are scattered by the natural ground G and escape from the soil, and a support unit 50e that supports the radiation source unit 50a and the thermal neutron detection unit 50b and is fixed to the skin plate 2.

[0031] Fast neutrons tend to convert into thermal neutrons as the soil and sand contain more water. The number of thermal neutrons is roughly proportional to the amount of hydrogen in the object being measured. Therefore, the amount of water (moisture content) in the natural ground G is calculated by detecting, with the thermal neutron detector 50b, the thermal neutrons converted from the fast neutrons emitted from the radiation source 50a due to the water content in the natural ground G.

[0032] The moisture content data of the natural ground G detected by the moisture meter 50 is transmitted to the controller 60.

[0033] As shown in Figures 3 to 5, the shield tunneling machine 1 further includes an inclined portion 40d extending from the outer peripheral surface of the skin plate 2 toward the end face of the density meter 40, and an inclined portion 50d extending from the outer peripheral surface of the skin plate 2 toward the end face of the moisture meter 50.

[0034] The inclined portions 40d, 50d are provided so as to surround the entire periphery of the end faces of the density meter 40 and the moisture meter 50, respectively. The inclination angle θ of the inclined portions 40d, 50d (the angle between the outer peripheral surface of the skin plate 2 and the inclined surfaces of the inclined portions 40d, 50d) is not particularly determined, but is preferably about 15° to 45°. Note that the inclined portions 40d, 50d only need to be provided at least in front of the density meter 40 and the moisture meter 50.

[0035] As described above, in the shield tunneling machine 1 of this embodiment, the outer diameter of the cutter head 3 is slightly larger than the outer diameter of the skin plate 2. Specifically, in this embodiment, the outer diameter of the cutter head 3 is approximately 20 cm larger than the outer diameter of the skin plate 2. As a result, an overexcavation section B exists between the inner wall W1 of the natural ground G and the outer peripheral surface of the skin plate 2. As described above, in the shield tunneling machine 1 of this embodiment, the density meter 40 and moisture meter 50 are arranged to protrude from the outer peripheral surface of the skin plate 2, and therefore, by providing the inclined sections 40d, 50d, it is possible to prevent the protruding parts of the density meter 40 and moisture meter 50 from directly hitting the earth and sand in the overexcavation section B and being damaged when the shield tunneling machine 1 moves forward.

[0036] Furthermore, for example, as shown in Figure 6, if the density meter 40 and the moisture meter 50 are arranged flush with the outer peripheral surface of the skin plate 2, the gamma rays and neutron rays emitted from the radiation source 40a of the density meter 40 and the radiation source 50a of the moisture meter 50 will pass through the excavated soil in the overexcavation section B. However, the excavated soil in the overexcavation section B may contain components other than the soil in the natural ground G, such as an aerating agent, and the properties of the soil detected by the density meter 40 and the moisture meter 50 may differ from the actual properties of the soil in the natural ground G. For this reason, if the density meter 40 and the moisture meter 50 are arranged flush with the outer peripheral surface of the skin plate 2 as shown in Figure 6, the properties of the soil in the natural ground G may not be accurately detected.

[0037] Therefore, in the shield tunneling machine 1 of this embodiment, the density meter 40 and moisture meter 50 are arranged to protrude from openings 2b, 2c provided in the outer peripheral surface of the skin plate 2. This makes it possible to reduce the influence of overexcavation B. Note that, in this case, it is preferable that the amount of protrusion P (see FIG. 5) of the density meter 40 and moisture meter 50 from the outer peripheral surface of the skin plate 2 is equal to (100%) the radial length of the overexcavation B, but if the amount of protrusion P of the density meter 40 and moisture meter 50 is at least 50% or more of the radial length H of the overexcavation B, it is possible to avoid contact between the density meter 40 and moisture meter 50 and the natural ground G while minimizing the influence of the overexcavation B as much as possible.

[0038] In the shield tunneling machine 1 of this embodiment, the density meter 40 and moisture meter 50 can be brought closer to the ground G in this way, in other words, the over-excavation section B that exists between the density meter 40 and moisture meter 50 and the soil and sand in the ground G can be eliminated, so that the properties of the soil and sand in the ground G can be accurately detected.

[0039] Furthermore, as the shield machine 1 continues excavating, the ground G above the shield machine 1 may become loose. In the shield machine 1 of this embodiment, the density meter 40 and moisture meter 50 are provided near the top of the skin plate 2, and by using the density meter 40 and moisture meter 50 to detect changes in the density and moisture content of the ground G above the skin plate 2, it is possible to more accurately predict the collapse of the ground G and control the excavation operation of the shield machine 1.

[0040] Furthermore, as excavation proceeds using the shield machine 1, it is necessary to manage the weight of the discharged soil. The weight of the discharged soil can be calculated based on the volume of the discharged soil (earth and sand from the excavated natural ground G) calculated based on the distance traveled by the shield machine 1, and the density and moisture content of the natural ground G detected by the density meter 40 and moisture meter 50. Therefore, by directly and accurately grasping the density and moisture content of the natural ground G, as in this embodiment, it is possible to more accurately manage the discharge of soil from the shield machine 1.

[0041] The shield machine 1 of the above embodiment provides the following advantages.

[0042] In the shield tunneling machine 1, the density meter 40 and moisture meter 50 are arranged to protrude from openings 2b, 2c provided on the outer peripheral surface of the skin plate 2, allowing the density meter 40 and moisture meter 50 to be brought closer to the ground G. This reduces the influence of the overexcavation section B, allowing the properties of the ground G to be detected accurately. As a result, it is possible to more accurately predict the collapse tendency of the ground G and control the excavation operation of the shield tunneling machine 1.

[0043] Furthermore, by setting the amount of protrusion P of the density meter 40 and moisture meter 50 from the outer surface of the skin plate 2 to between 50% and 100% of the radial length H of the overexcavation section B, the influence of the overexcavation section B can be reliably reduced while preventing the density meter 40 and moisture meter 50 from coming into contact with the ground G and being damaged.

[0044] In the shield tunneling machine 1, the density meter 40 and the moisture meter 50 are arranged side by side in the front-to-back direction of the shield tunneling machine 1, so that when the shield tunneling machine 1 moves forward, the density meter 40 and the moisture meter 50 pass through the same point in the ground G. This means that the density meter 40 and the moisture meter 50 detect the properties of the soil and sand at the same point in the ground G, improving the reliability of the detection results.

[0045] Additionally, in the shield tunneling machine 1, the outer peripheral surface of the skin plate 2 is provided with inclined portions 40d, 50d that extend from the outer peripheral surface toward the end faces of the density meter 40 and the moisture meter 50, respectively. This prevents the protruding parts of the density meter 40 and the moisture meter 50 from directly hitting the soil and sand in the overexcavation section B and being damaged when the shield tunneling machine 1 moves forward.

[0046] In the above embodiment, an example has been described in which the shield tunneling machine 1 is equipped with both the density meter 40 and the moisture meter 50, but this is not limiting, and the shield tunneling machine 1 may be equipped with only one of the density meter 40 and the moisture meter 50. Also, in the above embodiment, these are arranged side by side in the front-to-rear direction, but they may also be arranged offset in the circumferential direction.

[0047] In the above embodiment, an example was described in which one density meter 40 and one moisture meter 50 are installed near the top, but for example, in cases where the ground is prone to collapse, multiple meter meter 40 and 50 may be installed at intervals around the circumferential direction.

[0048] In the above embodiment, the inclined portions 40d and 50d are provided, but these are not necessarily provided. Also, instead of the inclined portions 40d and 50d, for example, tapered portions formed so that the width narrows in the front-to-rear direction from both side surfaces of the density meter 40 and the moisture meter 50 may be provided.

[0049] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0050] In the above embodiment, the shield machine 1 is used for the air bubble shield tunneling method, but other tunneling methods may also be used.

[0051] Furthermore, in the above embodiment, the density meter 40 and the moisture meter 50 have been described, but in addition to these, an earth pressure meter or the like may be provided so as to protrude from the outer peripheral surface of the skin plate 2 in the same manner as the density meter 40 and the moisture meter 50. [Explanation of symbols]

[0052] 1. Shield tunneling machine 2. Skin plate 2a Chamber 2b...Opening 2c...opening 3. Cutter head 4...Bulkhead 40 Density meter (detector) 40d...Slope part 50... Moisture meter (detector) 50d...Slope part 60... Controller B...Extra excavation part G. Ground P...Protrusion amount T···Shield Tunnel

Claims

1. A rotary cutter and a cylindrical skin plate provided behind the cutter and having a chamber inside in which soil excavated by the cutter accumulates; a detector for detecting at least one of the density of the soil and the moisture contained in the soil, The detector is arranged to protrude from an opening provided on the outer peripheral surface of the skin plate.

2. The shield tunneling machine according to claim 1, A shield tunneling machine, wherein the amount of protrusion of the detector from the outer peripheral surface of the skin plate is between 50% and 100% of the radial length of the overexcavation portion.

3. The shield tunneling machine according to claim 1 or 2, The detector comprises: a density meter for detecting the density of soil and sand in the ground; A moisture meter for detecting moisture contained in the soil and sand of the natural ground. A shield tunneling machine, wherein the density meter and the moisture meter are arranged side by side in the front-to-rear direction of the shield tunneling machine.

4. The shield tunneling machine according to claim 1 or 2, A shield tunneling machine, wherein the outer surface of the skin plate is provided with an inclined portion extending from the outer surface toward the end face of the detector.

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