Subsurface radar equipment

Abstract

To provide an underground radar device that interrupts an electromagnetic wave passing through a protection plate that protects a transmission antenna part and a receiving antenna part in an underground boring machine and an electromagnetic wave passing through a portion that is cut by a cutter, receives a surface propagation wave including appropriate soil property information, and has high discrimination accuracy of a soil property.SOLUTION: An underground radar device has a transmission antenna part 31 for transmitting an electromagnetic wave toward the front of an underground boring machine 1, a receiving antenna part 32 for receiving a surface propagation wave, a transmission antenna protection plate 30a that consists of a material penetrating an electromagnetic wave, is provided at a face plate 2 and protects the transmission antenna part 31, a receiving antenna protection plate 30b for protecting the receiving antenna part 32, a rear side electromagnetic wave cutoff part 33 that is provided at a periphery of the rear side of the transmission antenna part 31, and an electromagnetic wave cutoff part 34 provided along between the transmission antenna protection plate 30a and the receiving antenna protection plate 30b. The electromagnetic wave cutoff part 34 comprises a protruding part 34a that protrudes from the surface of the face plate 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an underground radar device that is installed on an underground tunneling machine and determines the soil type in front of the underground tunneling machine by using surface propagating waves. [Background technology]

[0002] In order to safely construct tunnels and other structures using underground tunneling machines, the excavation conditions must be set appropriately, and for this it is necessary to know the soil properties of the excavation route. A known technology for detecting and determining the soil quality of an excavation route is a radar device, a so-called underground radar device, which has a transmitting antenna and a receiving antenna that transmit and receive electromagnetic waves on a rotating face plate that has a cutter at the front end of the underground tunneling machine.

[0003] This underground radar device transmits electromagnetic waves forward from a transmitting antenna, and receives reflected waves that hit a reflecting object in front and surface propagating waves that propagate through the ground near the surface of the panel with a receiving antenna.The reflected waves can be used to determine the presence and location of obstacles, and the propagation speed and attenuation rate of the surface propagating waves can be used to determine the type of soil near the surface of the panel.

[0004] The transmitting antenna and receiving antenna are installed on the surface of a face plate provided at the front end of the underground tunneling machine, so a protective plate is provided on the face plate over the transmitting antenna and receiving antenna areas to protect them from earth pressure, water pressure, abrasion, etc., and the transmitting antenna and receiving antenna are attached to the back side of the protective plate.

[0005] Since such a protective plate is made of a material that transmits electromagnetic waves, the electromagnetic waves that pass from the transmitting antenna through the protective plate and reach the receiving antenna without passing through the ground are included in the surface propagating waves, which reduces the accuracy of soil type discrimination that should be based on the actual surface propagating waves.

[0006] For this reason, as described in Patent Document 1, an underground radar device has been proposed in which a protective plate that is transparent to electromagnetic waves is integrally attached to a part of the face plate, a transmitting antenna and a receiving antenna are installed on the back side of the protective plate, and an electromagnetic wave shielding section separates the transmitting antenna part from the receiving antenna part of the protective plate, blocking leakage electromagnetic waves that pass through the protective plate from the transmitting antenna to the receiving antenna without passing through the ground. This underground radar device blocks electromagnetic waves that pass from the transmitting antenna through a protective plate and reach the receiving antenna without passing through the ground, thereby improving the accuracy of determining soil type based on surface propagating waves. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Publication number 7-49427 Summary of the Invention [Problem to be solved by the invention]

[0008] Near the surface in front of the face plate, the natural ground is cut by the cutter attached to the face plate of the underground tunneling machine, and the natural ground in this area is cut and disturbed by the cutter. Such disturbed natural ground tends to have muddy water and groundwater infiltrate into the gaps, increasing the moisture content and decreasing the density, which affects the propagation speed of the surface propagation wave that passes through this part. For example, the propagation speed of the electromagnetic wave slows down as the moisture content increases.

[0009] The underground radar device described in the above Patent Document 1 can block electromagnetic waves that do not pass through the ground by passing through a protective plate, but cannot block surface propagating waves that pass through the natural ground disturbed by the cutter, and the soil quality information contained in the received surface propagating waves becomes inappropriate. Specifically, the part disturbed by the cutter is closer to the surface of the face plate than the part not disturbed, so the propagation distance of the electromagnetic wave is shorter, but the propagation speed of the electromagnetic wave is slower due to the increased moisture content, and the electromagnetic wave passing through the part disturbed by the cutter and the electromagnetic wave passing through the part not disturbed are likely to be received simultaneously, resulting in a lower ratio of surface propagating waves containing appropriate soil quality information that is originally desired to be obtained, and a decrease in the accuracy of soil quality discrimination. In other words, receiving more electromagnetic waves that have passed through the natural ground that is not disturbed leads to an improvement in the accuracy of soil quality discrimination. The inventors obtained this knowledge.

[0010] The problem that the present invention aims to solve is to provide an underground radar device in an underground tunneling machine that blocks electromagnetic waves that pass through a protective plate that protects the transmitting antenna unit and the receiving antenna unit, and electromagnetic waves that pass through parts of the ground cut by a cutter, and receives surface propagating waves that contain appropriate soil information, thereby enabling high accuracy in distinguishing the soil type ahead. [Means for solving the problem]

[0011] The invention of claim 1 is an underground radar device for determining the soil type in front, comprising a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine having a rotating face plate having cutters, a receiving antenna unit that receives at least surface propagating waves of the electromagnetic waves that propagate through the ground in front of the underground tunneling machine, a transmitting antenna protective plate made of a material that transmits electromagnetic waves and is attached to the face plate to protect the transmitting antenna unit, and a receiving antenna protective plate made of a material that transmits electromagnetic waves and is attached to the face plate to protect the receiving antenna unit, wherein the underground radar device has a rear electromagnetic wave blocking unit provided around the rear side of the transmitting antenna unit, and an electromagnetic wave blocking unit provided along the space between the transmitting antenna protective plate and the receiving antenna protective plate, the electromagnetic wave blocking unit having a protrusion that protrudes from the surface of the face plate, and characterized in that the underground radar device determines the soil type based on surface propagating waves received beyond the front of the protrusion. The invention according to claim 2 is the underground radar device according to claim 1, characterized in that the amount by which the protrusion protrudes from the surface of the face plate is within a range that can be cut by the cutter. The invention according to claim 3 is the underground radar device according to claim 1 or 2, characterized in that the protrusion is provided in a part of the center in the direction in which the electromagnetic wave blocking portion is provided. The invention of claim 4 is an underground radar device as described in any one of claims 1 to 3, characterized in that the protrusion has chamfered front both sides in a cross section cut along the rotation direction of the face plate. The invention according to claim 5 is the underground radar device according to any one of claims 1 to 4, characterized in that the electromagnetic wave blocking portion has a harder hardness than the face plate. The invention of claim 6 is an underground radar device described in any one of claims 1 to 5, characterized in that the electromagnetic wave blocking portion is movable in the forward / backward direction of the panel, and the amount by which the protrusion protrudes from the surface of the panel is adjustable. The invention of claim 7 is an underground radar device described in any one of claims 1 to 6, characterized in that the electromagnetic wave blocking portion is movable in the forward and backward directions of the panel, and the protrusion portion is movable from a state protruding from the surface of the panel to a state retracted from the surface of the panel. The invention of claim 8 is an underground radar device described in any one of claims 1 to 7, characterized in that the transmitting antenna unit and the receiving antenna unit are arranged side by side in the radial direction of the face plate, and the electromagnetic wave blocking unit is arranged along the rotational direction of the face plate. The invention of claim 9 is an underground radar device as described in any one of claims 1 to 7, characterized in that the transmitting antenna unit and the receiving antenna unit are arranged side by side in the rotational direction of the face plate, and the electromagnetic wave blocking unit is arranged along the radial direction of the face plate. The following may also be considered as another invention. Means 1is an underground radar device for determining the soil type in front, comprising: a transmitting antenna section which transmits electromagnetic waves toward the ground in front of an underground tunneling machine which has a rotating face plate having cutters; a receiving antenna section which receives at least surface propagating waves of the electromagnetic waves which propagate through the ground in front of the underground tunneling machine; a transmitting antenna protective plate which is made of a material that transmits electromagnetic waves and is attached to the face plate to protect the transmitting antenna section; and a receiving antenna protective plate which is made of a material that transmits electromagnetic waves and is attached to the face plate to protect the receiving antenna section. The underground radar device has a rear electromagnetic wave blocking section which is provided around the rear side of the transmitting antenna section, and an electromagnetic wave blocking section which is provided along the space between the transmitting antenna protective plate and the receiving antenna protective plate, and is characterized in that the electromagnetic wave blocking section has a protrusion which protrudes from the surface of the face plate.

[0012] Means 2 The amount by which the protrusion protrudes from the surface of the face plate is within a range that can be cut by the cutter. Means 1 The present invention relates to an underground radar device.

[0013] Means 3 The protrusion is provided in a part of a center portion in a direction in which the electromagnetic wave blocking portion is provided. Means 1 or Means 2 The present invention relates to an underground radar device.

[0014] Means 4 The protrusion has both front side corners chamfered in a cross section cut along the rotation direction of the face plate. Either of means 1 to 3 1 is a ground penetrating radar device according to the present invention.

[0015] Means 5 The electromagnetic wave blocking portion has a higher hardness than the face plate. Any of means 1 to 4 1 is a ground penetrating radar device according to the present invention.

[0016] Means 6The electromagnetic wave blocking portion is movable in the front-rear direction of the base plate, and the amount of protrusion of the protruding portion from the surface of the base plate is adjustable. Any of means 1 to 5 1 is a ground penetrating radar device according to the present invention.

[0017] Means 7 The electromagnetic wave blocking portion is movable in the front-rear direction of the base plate, and the protrusion is movable from a state in which it protrudes from the surface of the base plate to a state in which it is retracted from the surface of the base plate. Any of means 1 to 6 1 is a ground penetrating radar device according to the present invention.

[0018] Means 8 The transmitting antenna section and the receiving antenna section are arranged in a radial direction of the face plate, and the electromagnetic wave blocking section is arranged along a rotation direction of the face plate. Any of means 1 to 7 1 is a ground penetrating radar device according to the present invention.

[0019] Means 9 The transmitting antenna section and the receiving antenna section are arranged side by side in a rotation direction of the face plate, and the electromagnetic wave blocking section is arranged along a radial direction of the face plate. Any of means 1 to 7 1 is a ground penetrating radar device according to the present invention. Effect of the Invention

[0020] According to the present invention, the electromagnetic wave blocking section provided between the transmitting antenna protective plate and the receiving antenna protective plate has a protrusion that protrudes from the surface of the panel, so that electromagnetic waves that propagate from the transmitting antenna section through the transmitting antenna protective plate and the receiving antenna protective plate without passing through the ground, and electromagnetic waves that propagate through parts of the ground that are pushed aside by the cutter, are blocked and not received by the receiving antenna section.This makes it possible to increase the proportion of surface propagating waves that contain appropriate soil type information and are the intended source of information, thereby improving the accuracy of soil type determination.

[0021] In addition, by setting the amount by which the protrusion of the electromagnetic wave blocking section protrudes from the surface of the face plate within the range that can be cut by the cutter, electromagnetic waves propagating in parts of the ground that are not cut off by the cutter are not blocked, and surface propagating waves containing appropriate soil information can be reliably received.

[0022] In addition, the protruding portion of the electromagnetic wave blocking portion is provided in a portion of the center in the direction in which the electromagnetic wave blocking portion is provided. Since electromagnetic waves of surface propagation waves tend to pass mostly through the center between the transmitting antenna portion and the receiving antenna portion, even such a partial protruding portion can sufficiently block electromagnetic waves passing through the protective plate and the portion of the ground that is disturbed by the cutters. Furthermore, the resistance received by the protruding portion is reduced, improving durability and suppressing the rotation torque of the face plate.

[0023] In addition, the protrusion of the electromagnetic wave blocking part has chamfered corners on both front sides in a cross section cut along the rotation direction of the face plate, which reduces the resistance when the face plate rotates and also reduces the resistance applied to the protrusion of the electromagnetic wave blocking part when the face plate rotates while digging, thereby improving the durability of the electromagnetic wave blocking part.

[0024] In addition, since the electromagnetic wave blocking portion has a harder hardness than the face plate, the resistance to wear of the electromagnetic wave blocking portion can be improved.

[0025] In addition, the electromagnetic wave blocking portion can be moved in the front-to-back direction of the face plate, and the amount by which the protrusion protrudes from the surface of the face plate can be adjusted, so that the amount of protrusion can be adjusted according to the excavation state of the underground tunneling machine.

[0026] In addition, since the electromagnetic wave blocking portion is movable in the front-rear direction of the face plate and the protruding portion can move from a state where it protrudes from the surface of the face plate to a state where it is retracted from the surface of the face plate, wear and damage can be prevented by retracting the protruding portion when the underground radar device is not in use. Also, by contrasting the protruding portion, it is possible to receive electromagnetic waves without the electromagnetic wave blocking portion between the protective plates, and it is possible to receive electromagnetic waves that pass through the protective plates and are close to not passing through the ground, which can be used as data when initializing soil type discrimination.

[0027] In addition, if the transmitting antenna section and the receiving antenna section are arranged in the radial direction of the face plate and the electromagnetic wave blocking section is arranged along the rotational direction of the face plate, the side area of ​​the protrusion of the electromagnetic wave blocking section facing the rotational direction of the face plate is reduced, thereby reducing the resistance experienced by the protrusion and requiring less rotational torque for the face plate.Moreover, even if the transmitting antenna section and the receiving antenna section are arranged in the radial direction, there is no hindrance to determining the soil type by transmitting and receiving surface propagating waves.

[0028] In addition, by arranging the transmitting antenna unit and the receiving antenna unit side by side in the rotational direction of the face plate, i.e., in the circumferential direction, and arranging the electromagnetic wave blocking unit along the radial direction of the face plate, it is possible to properly determine the soil type by transmitting and receiving surface propagating waves, and the circumferential arrangement of the transmitting antenna unit and the receiving antenna unit also ensures the ability to detect the presence and location of obstacles by receiving reflected waves. Furthermore, if the protrusion is provided in a part of the radial center, the protrusion of the electromagnetic wave blocking part can be small, thereby reducing the resistance applied to the protrusion and suppressing the rotational torque of the face plate. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a front view of an underground excavator according to a first embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view taken along a radial direction of a ground penetrating radar device according to a first embodiment of the present invention. [Diagram 3]6 is a cross-sectional view taken along the circumferential direction of an electromagnetic wave blocking unit according to a second embodiment of the present invention. FIG. [Figure 4] 11 is a cross-sectional view taken along the circumferential direction of an electromagnetic wave blocking portion according to a third embodiment of the present invention. FIG. [Diagram 5] FIG. 11 is a cross-sectional view of a main part along a radial direction of a ground penetrating radar device showing a fourth embodiment of the present invention. [Figure 6] FIG. 11 is a front view of an underground tunneling machine according to a fifth embodiment of the present invention. [Figure 7] FIG. 13 is a front view of an underground tunneling machine according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, etc. It should be noted that the present invention is not limited to the embodiment.

[0031] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front view of an underground excavator according to a first embodiment, and FIG. 2 is a cross-sectional view of an underground radar device according to the first embodiment. In the following description, the direction in which the underground tunneling machine excavates is referred to as "forward," and the opposite direction is referred to as "backward."

[0032] As shown in Figure 1, the underground tunneling machine 1 is a shield tunneling machine used in the shield tunneling method, and is provided at its front end with a circular face plate 2. A plurality of cutters 20, each having a large number of bits 20a arranged thereon, are attached radially to the surface of the face plate 2, and slits 21 are formed adjacent to the cutters 20. The underground tunneling machine 1 then rotates the face plate 2 to excavate the ground with the cutter 20 and advances while taking in soil through the slits 21.

[0033] An underground radar device 3 is installed on the face plate 2. The underground radar device 3 transmits electromagnetic waves forward from a transmitting antenna, and receives, with a receiving antenna, reflected waves that hit a reflecting object in front and surface propagating waves that propagate through the ground near the surface in front of the face plate. The reflected waves are used to determine the presence and position of obstacles, and the propagation speed and attenuation rate of the surface propagating waves are used to determine the soil type near the surface of the face plate.

[0034] As shown in FIG. 2, the underground radar device 3 includes two protective plates, a transmitting antenna protective plate 30a and a receiving antenna protective plate 30b, a transmitting antenna section 31, a receiving antenna section 32, a rear-side electromagnetic wave blocking section 33, and an electromagnetic wave blocking section 34.

[0035] The face plate 2 is usually made of a strong material such as iron that does not easily transmit electromagnetic waves, so openings 35 are formed at the positions where the transmitting antenna unit 31 and the receiving antenna unit 32 are to be installed. The openings 35 are formed to avoid the areas where the cutter 20 and the slits 21 are provided.

[0036] The transmitting antenna protective plate 30a and the receiving antenna protective plate 30b are made of a strong material such as FRP that is transparent to electromagnetic waves, and are arranged radially of the face plate 2 and fitted into the opening 35 so as to be adjacent to each other with a gap 300 between them, thereby becoming part of the face plate 2. In this embodiment, the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b are provided so as to be flush with the surface of the face plate 2, but this is not limiting and, for example, they may be provided slightly set back as a measure against wear.

[0037] The transmitting antenna section 31 transmits electromagnetic waves for underground detection, and is attached in close contact with the rear surface of the transmitting antenna protective plate 30a, and is protected from earth pressure, water pressure, and earth and sand. The receiving antenna section 32 receives the electromagnetic waves transmitted by the transmitting antenna section 31, and is attached in close contact with the rear surface side of the receiving antenna protective plate 30b, and is protected from earth pressure, water pressure, and earth and sand.

[0038] The transmitting antenna unit 31 transmits electromagnetic waves as appropriate while the face plate 2 is rotating or stopped, and the receiving antenna unit 32 receives the electromagnetic waves. For example, if an electromagnetic wave is transmitted every time the face plate 2 rotates one degree, transmission and reception are performed 360 times while the face plate 2 rotates one degree.

[0039] The rear-side electromagnetic wave blocking section 33 is made of a material such as iron that is difficult for electromagnetic waves to transmit, has an open front, and is provided on the rear surface of the face plate 2 so as to cover the opening 35 of the face plate 2 from the rear side. The rear-side electromagnetic wave blocking section 33 also functions as a housing for accommodating the transmitting antenna section 31 and the receiving antenna section 32 therein, is formed in a box shape, and is provided with a partition wall 330 that separates the transmitting antenna section 31 from the receiving antenna section 32. Therefore, the rear-side electromagnetic wave blocking section 33 is provided surrounding the periphery on the rear side of the transmitting antenna section 31, and prevents leakage of electromagnetic waves on the rear side of the face plate 2 of the transmitting antenna section 31.

[0040] In addition, the rear-side electromagnetic wave blocking section 33 may be configured so that the space in which the box-shaped transmitting antenna section 31 and receiving antenna section 32 are housed is further filled with a material with a high relative dielectric constant to prevent diffuse reflection of electromagnetic waves.

[0041] The partition wall 330 of the rear-side electromagnetic wave blocking section 33 is provided on the rear side of the face plate 2 at a position coinciding with the gap 300 between the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b. Furthermore, the bulkhead 330 is formed with a through hole 331 for passing a cable connecting the transmitting antenna unit 31 and the receiving antenna unit 32, and after the cable connection is completed, the through hole 331 is blocked with a material that blocks electromagnetic waves to prevent leakage of electromagnetic waves from the through hole 331. Note that the through hole 331 does not have to be provided in the bulkhead 330, and may be provided in another wall portion to connect cables to the transmitting antenna unit 31 and the receiving antenna unit 32, respectively.

[0042] The electromagnetic wave blocking section 34 is made of a material such as iron that is difficult for electromagnetic waves to transmit and that is harder than the face plate 2, and is provided on the front end surface of the partition wall 330 and positioned in the gap 300 between the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b.

[0043] The electromagnetic wave blocking section 34 separates the transmitting antenna protective plate 30a and the receiving antenna protective plate 30b, and blocks the electromagnetic waves transmitted from the transmitting antenna section 31 from propagating from the transmitting antenna protective plate 30a through the receiving antenna protective plate 30b to the receiving antenna section 32. The electromagnetic wave blocking portion 34 may be integrally formed with the partition wall 330, or may be a separate electromagnetic wave blocking portion 34 fixed to the partition wall 330 by welding or the like.

[0044] The electromagnetic wave blocking portion 34 has a protruding portion 34 a that protrudes from the surface of the face plate 2 .

[0045] The transmitting antenna unit 31 transmits electromagnetic waves through the transmitting antenna protective plate 30a into the ground in front. The electromagnetic waves transmitted from the transmitting antenna unit 31 are received by the receiving antenna unit 32. The electromagnetic waves received by the receiving antenna unit 32 include surface propagating waves that propagate near the surface in front of the face plate 2. By evaluating the voltage value, arrival time, etc. of the surface propagating waves, it is possible to determine the soil type of the ground through which the waves have passed.

[0046] The part A of the natural ground near the surface of the face plate 2 is cut and disturbed by the cutter 20, and the moisture content increases and the density decreases. Therefore, this part A cannot be said to be the natural state of the natural ground. In other words, the surface propagating wave passing through this part A contains inappropriate soil information. The electromagnetic wave blocking portion 34 has a protruding portion 34a that protrudes from the surface of the face plate 2, so that it is possible to block electromagnetic waves that pass through the portion A of the natural ground that is disturbed by the cutter 20.

[0047] If the protruding portion 34a protrudes beyond the portion A of the natural ground that is cut and disturbed by the cutter 20, the surface propagating waves that are intended to be acquired will be blocked, and therefore it is preferable that the protruding portion 34a of the electromagnetic wave blocking portion 34 remain in this portion A in the ground. In other words, it is preferable that the amount by which the protruding portion 34a protrudes from the surface of the face plate 2 is within the range cut by the cutter 20. Furthermore, if the protruding portion 34a is within the range of the portion A of the natural ground that is cut and disturbed by the cutter 20, wear and damage to the protruding portion 34a can be reduced.

[0048] In order to reliably increase the proportion of surface propagating waves that are originally desired to be acquired, the protruding portion 34a of the natural ground may be provided beyond the portion A of the natural ground that is cut and pushed aside by the cutter 20. Furthermore, if the protrusion 34a is present in part A of the natural ground that is cut and disturbed by the cutter 20, the proportion of surface propagating waves that are originally acquired, including above the appropriate soil, can be increased accordingly, and it is not necessary for the protrusion 34a to be present over the entirety of the cut and disturbed part A.

[0049] As an example of setting the protrusion amount d of the protrusion 34a from the surface of the face plate 2, Let hv be the height of the cutter 20 from the surface of the face plate 2 (height of the bit 20a), L be the advancement amount of the antenna installation part until a new bit is cut, v be the tunneling speed of the underground tunneling machine 1, R be the number of rotations of the face plate 2 per unit time, n be the number of passes of the same row of bit 20a during one rotation of the face plate 2 (the so-called number of passes), and S be the margin (usually about 10 to 30 mm). (Equation 1) d = hv-LS = hv-v / (R × n)-S It becomes. For example, if hv=80mm, v=50mm / min, R=1 rotation / min, n=2, and S=20mm, d=80mm-50 / (1×2)-20=20mm.

[0050] The transmitting antenna section 31 and the receiving antenna section 32 are installed adjacent to each other in the radial direction of the face plate 2, and since the gap 300 between the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b is relatively narrow, the radial dimension of the face plate 2 of the electromagnetic wave blocking section 34 that separates the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b is shorter than its circumferential dimension, and as a result, the resistance experienced by the protrusion 34a of the electromagnetic wave blocking section 34 when the face plate 2 rotates is small.

[0051] In addition, by arranging the transmitting antenna section 31 and the receiving antenna section 32 side by side in the radial direction of the base plate 2, the accuracy of determining the position and distance of a reflecting object by transmitting and receiving reflected waves from the front is relatively lower than when the transmitting antenna section 31 and the receiving antenna section 32 are arranged in the circumferential direction, which is the rotation direction of the base plate 2, but there is no problem with transmitting and receiving surface propagating waves. That is, in this embodiment, the arrangement is such that the obstacle detection performance is reduced in exchange for improving soil type discrimination performance.

[0052] Second Embodiment A second embodiment of the present invention will be described below with reference to Fig. 3. Note that a description of the same parts as in the first embodiment will be omitted, and differences will be mainly described.

[0053] The second embodiment differs from the first embodiment in the shape of the protrusion 34a. In the second embodiment, the protrusion 34a protruding from the surface of the face plate 2 of the electromagnetic wave blocking unit 34 has both front side corners chamfered in a cross section cut along the rotation direction of the face plate 2. Specifically, the chamfered corners are curved in an arc shape. This reduces the resistance when the face plate 2 rotates, and also reduces the resistance applied to the protrusion 34a of the electromagnetic wave blocking portion 34 when the face plate 2 rotates while digging, thereby improving the durability of the electromagnetic wave blocking portion 34.

[0054] Third embodiment Hereinafter, a third embodiment of the present invention will be described with reference to Fig. 4. Note that a description of the same parts as in the first and second embodiments will be omitted, and the following mainly describes the different parts.

[0055] The third embodiment differs from the second embodiment in the protrusion 34a. In the third embodiment, the protrusion 34a is provided in a part of the center in the direction in which the electromagnetic wave blocking portion 34 is provided.

[0056] Most of the surface propagating waves that pass through the part A of the ground cut and disturbed by the cutter 20 pass through the central part of the opposing sides of the transmitting antenna unit 31 and the receiving antenna unit 32. Therefore, by providing a protrusion 34a at this central part to block it, the proportion of these surface propagating waves can be reduced and the surface propagating waves that should be obtained, which contain a lot of appropriate ground information, can be obtained. The dimension of the protrusion 34a provided in a portion of the radial center of the face plate 2 is set to, for example, about 3 / 4 to 1 / 2 of the radial side length of the transmitting antenna section 31.

[0057] Since the protrusion 34a of the electromagnetic wave blocking portion 34 is provided only in the central portion between the transmitting antenna portion 31 and the receiving antenna portion 32, the resistance to rotation of the face plate 2 can be made relatively small, and the resistance applied to the protrusion 34a of the electromagnetic wave blocking portion 34 is also small, improving durability.

[0058] [Fourth embodiment] Hereinafter, a fourth embodiment of the present invention will be described with reference to Fig. 5. Note that a description of the same parts as in the first to third embodiments will be omitted, and the following mainly describes the different parts.

[0059] The fourth embodiment differs from the previous embodiments in that the electromagnetic wave blocking portion 34 is movable in the front-rear direction relative to the face plate 2. In the fourth embodiment, the partition wall 330 is formed as two partition walls 330a, 330b, and a jack 36 is disposed between them. The electromagnetic wave blocking portion 34 is provided at the front end of the jack 36. The jack 36 expands and contracts in the front-rear direction (the up-down direction on the paper in FIG. 5) and can move the electromagnetic wave blocking portion 34 in the front-rear direction of the face plate.

[0060] The extension range of the jack 36 is from a state in which the protrusion 34a of the electromagnetic wave blocking part 34 protrudes from the surface of the face plate 2 to a state in which it is retracted (backed away) from the surface of the face plate 2. Fig. 4 shows a state in which the protrusion 34a is in the most retracted state, flush with the rear surfaces of the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b.

[0061] When electromagnetic waves are transmitted and received in this retracted state, transmission and reception can be performed without the electromagnetic wave blocking section 34 separating the transmitting antenna protective plate 30a and the receiving antenna protective plate 30b, and therefore, for example, this can be used to perform settings such as initialization of the underground radar device 3. In particular, when the gap 300 is narrow and the electromagnetic waves can sufficiently propagate between the transmitting antenna protective plate 30a and the receiving antenna protective plate 30b, the space between the transmitting antenna protective plate 30a and the receiving antenna protective plate 30b can be approximately placed in an unblocked state, and this can be used to perform settings such as initialization.

[0062] In addition, by extending and retracting the jack 36 in the ground, soil and sand adhering to the electromagnetic wave blocking portion 34 can be removed.

[0063] By controlling the extension / retraction amount of the jack 36, it is also possible to adjust the amount by which the protrusion 34a of the electromagnetic wave blocking part 34 protrudes from the surface of the face plate 2. Therefore, the amount of protrusion can be appropriately set according to the excavation conditions, such as the rotation speed R of the face plate 2 of the underground tunneling machine 1 and the excavation speed v.

[0064] Fifth embodiment Hereinafter, a fifth embodiment of the present invention will be described with reference to Fig. 6. Note that a description of the same parts as in the first to fourth embodiments will be omitted, and differences will be mainly described.

[0065] The fifth embodiment differs from the first embodiment in the arrangement of the transmitting antenna section 31 and the receiving antenna section 32 on the face plate 2. In the fifth embodiment, the transmitting antenna section 31 and the receiving antenna section 32 are arranged side by side in the circumferential direction, which is the rotation direction of the face plate 2. The gap 300 between the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b is arranged along the radial direction of the face plate 2, and the electromagnetic wave blocking portion 34 and the protrusion 34a that separate the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b are also arranged along the radial direction of the face plate 2.

[0066] Since the transmitting antenna section 31 and the receiving antenna section 32 are arranged side by side in the rotational direction of the panel 2, the accuracy of determining the position and distance of a reflecting object by transmitting and receiving reflected waves as well as transmitting and receiving surface propagating waves is improved, and obstacle detection performance can also be ensured.

[0067] Sixth embodiment Hereinafter, the sixth embodiment of the present invention will be described with reference to Fig. 7. Note that a description of the same parts as the first to fifth embodiments will be omitted, and differences will be mainly described.

[0068] The sixth embodiment differs from the third embodiment in the arrangement of the transmitting antenna section 31 and the receiving antenna section 32 on the face plate 2. In the sixth embodiment, the transmitting antenna section 31 and the receiving antenna section 32 are arranged side by side in the circumferential direction, which is the rotation direction of the face plate 2.

[0069] The gap 300 between the transmitting antenna protective plate 30a and the receiving antenna protective plate 30b is arranged along the radial direction of the face plate 2, and the electromagnetic wave blocking section 34 separating the transmitting antenna protective plate 30a and the receiving antenna protective plate 30b is also arranged along the radial direction of the face plate 2, but the protrusion 34a is provided only in a portion of the radial center of the face plate 2, between the transmitting antenna section 31 and the receiving antenna section 32.

[0070] Specifically, the electromagnetic wave blocking section 34, which separates the protrusion 34a and the receiving antenna protection plate 30a and the receiving antenna protection plate 30b behind it, is formed from a material different from the face plate 2 (e.g., a material harder than the face plate 2), and in the other parts of the gap 300 on both radial sides (the top and bottom of the paper in Figure 7) of the electromagnetic wave blocking section 34 behind the protrusion 34a, parts of the face plate 2 are extended to close the gap 300 between the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b, thereby forming the electromagnetic wave blocking section 34.

[0071] Alternatively, instead of extending the face plate 2, as in the third embodiment, the electromagnetic wave blocking portion 34 separating the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b may be formed entirely along the gap 300 using a material different from the face plate 2, and the protrusion 34a may be provided in a portion of the radial center of the face plate 2.

[0072] As the face plate 2 rotates, the transmitting antenna section 31 and the receiving antenna section 32 move continuously in the circumferential direction. However, since the protrusion 34a of the electromagnetic wave blocking section 34 is provided only in the central section between the transmitting antenna section 31 and the receiving antenna section 32, the resistance to the rotation of the face plate 2 can be made relatively small, and the resistance applied to the protrusion 34a of the electromagnetic wave blocking section 34 is also small, improving durability. Furthermore, since the transmitting antenna section 31 and the receiving antenna section 32 are arranged side by side in the rotational direction of the panel 2, it is suitable not only for transmitting and receiving surface propagating waves, but also for determining the position and distance of a reflecting object by transmitting and receiving reflected waves, and obstacle detection performance can also be ensured.

[0073] [Other Modifications] The present invention is not limited to the above-mentioned embodiment, and may also include the following, for example.

[0074] In this embodiment, a through hole 331 is formed in the partition 330 of the rear-side electromagnetic wave blocking section 33 to pass a cable connecting the transmitting antenna section 31 and the receiving antenna section 32, and after the cable connection is completed, the through hole 331 is blocked with a material that blocks electromagnetic waves. However, it is also possible not to form the through hole 331 in the partition, but to take electromagnetic wave blocking measures and embed the cable connection terminal in the partition 330 in advance.

[0075] In the second embodiment, the transmitting antenna section 31 and the receiving antenna section 32 are arranged side by side in the radial direction of the face plate 2, the electromagnetic wave blocking section 34 is long in the rotation direction of the face plate 2, and the protruding section 34a of the electromagnetic wave blocking section 34 has both front side corners chamfered in a cross section cut along the rotation direction of the face plate 2. When the transmitting antenna section 31 and the receiving antenna section 32 are arranged side by side in the circumferential direction of the face plate 2 and the electromagnetic wave blocking section 34 is arranged along the radial direction of the face plate 2 as in the fifth and sixth embodiments, if the protruding section 34a of the electromagnetic wave blocking section 34 has both front side corners chamfered in a cross section cut perpendicular to the radial direction of the face plate 2, the resistance when the face plate 2 rotates is reduced, and the resistance applied to the protruding section 34a of the electromagnetic wave blocking section 34 when the face plate 2 is excavated while rotating is reduced, and the durability of the electromagnetic wave blocking section 34 can also be improved.

[0076] In this embodiment, the underground tunneling machine is a shield tunneling machine used in the shield construction method, but this is not limited to this, and any underground tunneling machine equipped with a rotating face plate having a cutter may be used in the jacking construction method or the TBM construction method.

[0077] In this embodiment, the surface of the face plate 2 is flush with the surfaces of the transmitting antenna protection plate 30a and the receiving antenna protection plate 30b, but this is not limited to the above. For example, the surfaces of the transmitting antenna protection plate and the receiving antenna protection plate may be recessed from the surface of the face plate as a measure against wear. Even in such a configuration, the protruding portion protrudes from the surface of the face plate.

[0078] Each technical matter in any embodiment may be applied to another embodiment to serve as an example. [Explanation of symbols]

[0079] 1 Underground digging machine 2 face plates 20 Cutter 20a bit 21 Slit 3. Subsurface radar equipment 30a Transmitting antenna protection plate 30b Receiving antenna protection plate 300 gap 31 Transmitting antenna section 32 Receiving antenna section 33 Rear electromagnetic wave shielding section 330 Bulkhead 331 Through hole 34 Electromagnetic wave blocking section 34a Protrusion 35 Opening 36 Jack

Claims

1. An underground radar device for determining soil type ahead, comprising: a transmitting antenna section which transmits electromagnetic waves towards the ground ahead of an underground tunneling machine having a rotating face plate having cutters; a receiving antenna section which receives at least surface propagating waves of the electromagnetic waves which propagate through the ground ahead of the underground tunneling machine; a transmitting antenna protective plate which is made of a material which transmits electromagnetic waves and is attached to the face plate and protects the transmitting antenna section; and a receiving antenna protective plate which is made of a material which transmits electromagnetic waves and is attached to the face plate and protects the receiving antenna section, a rear-side electromagnetic wave blocking section provided around a rear side of the transmitting antenna section; an electromagnetic wave blocking section provided along a space between the transmitting antenna protection plate and the receiving antenna protection plate, the electromagnetic wave blocking portion includes a protrusion protruding from a surface of the face plate, The soil type is determined based on the surface propagation waves received beyond the front of the protrusion.

1. A ground penetrating radar device comprising:

2. 2. The underground radar device according to claim 1, wherein an amount by which the protrusion protrudes from the surface of the face plate is within a range that can be cut by the cutter.

3. 3. The underground radar device according to claim 1, wherein the protrusion is provided in a part of a center portion in a direction in which the electromagnetic wave blocking portion is provided.

4. 4. The underground radar device according to claim 1, wherein the protrusion has both front side corners chamfered in a cross section cut along the rotation direction of the face plate.

5. 5. The underground radar device according to claim 1, wherein the electromagnetic wave blocking portion has a harder hardness than the face plate.

6. 6. The underground radar device according to claim 1, wherein the electromagnetic wave blocking portion is movable in the front-to-rear direction of the face plate, and the amount by which the protrusion protrudes from the surface of the face plate is adjustable.

7. 7. The underground radar device according to claim 1, wherein the electromagnetic wave blocking portion is movable in the front-to-rear direction of the face plate, and the protrusion is movable from a state in which it protrudes from the surface of the face plate to a state in which it is retracted from the surface of the face plate.

8. 8. An underground radar device according to claim 1, wherein the transmitting antenna section and the receiving antenna section are arranged in a radial direction of the face plate, and the electromagnetic wave blocking section is arranged along the rotational direction of the face plate.

9. 8. The underground radar device according to claim 1, wherein the transmitting antenna section and the receiving antenna section are arranged side by side in the rotational direction of the face plate, and the electromagnetic wave blocking section is arranged along the radial direction of the face plate.

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