Ground-penetrating radar device

Abstract

To provide a ground penetrating radar device which allows for determining not only water content of a soil layer but also the presence or absence of underground cavities at a tunnel face and determining excessive extraction of excavated soil.SOLUTION: A ground penetrating radar device is provided, comprising a transmission antenna unit 31 for transmitting an electromagnetic wave into ground in front of an underground excavator 1, a reception antenna unit 32 for receiving at least a surface propagation wave of the electromagnetic wave, and a determination unit 33. The determination unit 33 is configured to compare propagation time from transmission to reception of the surface propagation wave and reference propagation time from transmission to reception of a surface propagation wave propagating along a normal soil layer, and determines the presence of a risk of excessive extraction when the propagation time is longer or shorter than the reference propagation time.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 whether or not excessive excavated soil and sand are being taken in by using surface propagation 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 understand the soil quality to be excavated. As a technology for detecting and determining the soil quality of an excavation route, for example, Patent Documents 1 and 2 disclose a radar device, a so-called underground radar device, in which a transmitting antenna and a receiving antenna are installed on a rotating face plate that has a cutter at the front end of an underground tunneling machine and transmits and receives electromagnetic waves.

[0003] Such underground radar devices transmit electromagnetic waves forward from a transmitting antenna, and receive reflected waves that hit a reflecting object in front of the device and surface propagating waves that propagate through the ground near the surface of the faceplate with a receiving antenna. The presence and location of obstacles can be determined by the reflected waves, and the propagation speed and attenuation rate of the surface propagation waves can be used to determine the soil quality near the surface of the face plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 4-131792 [Patent Document 2] Special Publication No. 6-16116 Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, there have been a number of cases of above-ground cave-ins caused by excessive intake of excavated soil during construction work using underground tunneling machines, which have had a major impact on the surrounding environment and have become a social problem. If too much excavated soil is taken in, the ground near the front of the face plate may be disturbed, resulting in areas with few soil particles and mostly consisting of muddy water or groundwater, or the soil may collapse, creating cavities in the ground, or if air bubbles are added, they may accumulate in some areas.

[0006] In this way, when the moisture content of the soil layer increases or cavities appear, it affects the propagation speed of the surface propagation wave that passes through this part.For example, the propagation speed of the electromagnetic wave decreases when the moisture content increases, and increases when there are many air bubbles or cavities.The inventors discovered this and came to use an underground radar device for determining soil quality to determine whether excessive excavated soil has been taken in.

[0007] An object of the present invention is to provide an underground radar device that can determine not only the moisture content of the soil layer but also the presence or absence of air bubbles or cavities at the working face, and can determine whether or not excessive excavated soil or sand has been taken in. [Means for solving the problem]

[0008] The invention of claim 1 is an underground radar device comprising a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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 judgment unit, and an alarm unit, wherein the judgment unit compares the propagation time taken from the time of transmission to the time of reception of the received surface propagating wave with a reference propagation time taken from the time of transmission to the time of reception of a surface propagating wave when propagating through a normal soil layer that is stored as not being at risk of over-intake, and judges whether the propagation time is longer or shorter than the reference propagation time, and if the propagation time is longer or shorter than the reference propagation time, it sends out a signal that the received surface propagating wave is an abnormal wave and there is a risk of over-intake, and the alarm unit receives the signal and issues an alarm that there is a risk of over-intake. The invention of claim 2 is an underground radar device comprising a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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 judgment unit, and an alarm unit, wherein the judgment unit compares the wavelength of the received surface propagating wave with a reference wavelength of a surface propagating wave when propagating through a normal soil layer that is stored as not being at risk of over-intake, and judges whether the wavelength is longer or shorter than the reference wavelength, and if the wavelength is longer or shorter than the reference wavelength, sends out a signal that the received surface propagating wave is an abnormal wave and there is a risk of over-intake, and the alarm unit receives the signal and issues an alarm that there is a risk of over-intake. The invention of claim 3 is an underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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; and a judgment unit, wherein the judgment unit compares the propagation time taken from the time of transmission of the received surface propagating wave to the time of reception with a reference propagation time taken for a surface propagating wave to propagate through a normal soil layer from the time of transmission to the time of reception, and judges whether the propagation time is longer or shorter than the reference propagation time, and if the propagation time is longer or shorter than the reference propagation time, calculates the difference between the propagation time and the reference propagation time, and sends out a signal indicating the level of risk of over-intake based on an index set in accordance with the difference. The invention of claim 4 is an underground radar device comprising a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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, and a judgment unit, wherein the judgment unit compares the wavelength of the received surface propagating waves with a reference wavelength of surface propagating waves when they propagate through a normal soil layer to judge whether the wavelength is longer or shorter than the reference wavelength, and if the wavelength is longer or shorter than the reference wavelength, calculates the difference between the wavelength and the reference wavelength and sends out a signal indicating the level of risk of over-intake based on an index set according to the difference. The invention of claim 5 is an underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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; and a judgment unit, wherein the judgment unit compares the propagation time taken from the time of transmission to the time of reception of the received surface propagating wave for each predetermined rotation angle of the face plate with a reference propagation time taken from the time of transmission to the time of reception of a surface propagating wave when propagating through a normal soil layer, and judges whether the propagation time is longer or shorter than the reference propagation time, and if the propagation time is longer or shorter than the reference propagation time, determines that the received surface propagating wave is an abnormal wave, specifies the frequency of the abnormal wave during the predetermined rotations of the face plate, and sends out a signal indicating the level of risk of over-intake based on an index set according to the frequency. The invention of claim 6 is an underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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; and a judgment unit, wherein the judgment unit compares the wavelength of the received surface propagating wave for each predetermined rotation angle of the face plate with a reference wavelength of a surface propagating wave when propagating through a normal soil layer, and judges whether the wavelength is longer or shorter than the reference wavelength, and if the wavelength is longer or shorter than the reference wavelength, determines that the received surface propagating wave is an abnormal wave, specifies the frequency of the abnormal wave during the predetermined rotation of the face plate, and sends out a signal indicating the level of risk of over-intake based on an index set according to the frequency. The invention of claim 7 is the underground radar device according to claim 5 or claim 6, characterized in that the judgment unit calculates the degree of discretization of the rotational position of the face plate that has caused the abnormal wave during a predetermined rotation of the face plate, corrects the frequency of the abnormal wave by a correction coefficient set according to the degree of discretization, and sends out a signal indicating the level of risk of over-intake based on an index set according to the frequency. The invention of claim 8 is an underground radar device according to any one of claims 5 to 7, characterized in that the judgment unit identifies a weighting coefficient of abnormality set according to the position of the face where the received surface propagating wave is determined to be an abnormal wave, and sends out a signal indicating the level of risk of over-intake based on the index set also based on the weighting coefficient. The invention of claim 9 is the underground radar device according to claim 8, characterized in that the weighting coefficients are set so that those above the face are weighted more heavily than those below the face. The following may also be considered as a separate invention. Means 1is an underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with a rotating face plate having cutters; a receiving antenna unit that receives at least the surface propagating waves of the electromagnetic waves that propagate through the ground in front of the underground tunneling machine; and a judgment unit, wherein the judgment unit compares the propagation time taken from the time of transmission to the time of reception of the received surface propagating wave with a reference propagation time taken from the time of transmission to the time of reception of a surface propagating wave when it normally propagates through a soil layer, and judges that there is a risk of over-intake if the propagation time is longer or shorter than the reference propagation time.

[0009] Means 2 is an underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that is equipped with 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; and a judgment unit, wherein the judgment unit compares the wavelength of the received surface propagating waves with a reference wavelength of surface propagating waves when they normally propagate through soil layers, and judges that there is a risk of over-intake if the wavelength is longer or shorter than the reference wavelength.

[0010] Means 3 The determining unit determines the level of risk of over-intake depending on the degree of difference between the propagation time and the reference propagation time. Means 1 2. The underground radar device according to claim 1,

[0011] Means 4 The determining unit determines the level of risk of excessive intake depending on the degree of difference between the wavelength and the reference wavelength. Means 2 2. The underground radar device according to claim 1,

[0012] Means 5The determination unit compares the propagation time with the reference propagation time for each predetermined rotation angle of the face plate, and determines that the level of risk of over-uptake is high depending on the frequency with which the risk of over-uptake is determined to exist when the propagation time is longer or shorter than the reference propagation time during one rotation of the face plate. Means 1 or Means 3 2. The underground radar device according to claim 1,

[0013] Means 6 the determining unit compares the wavelength with the reference wavelength for each predetermined rotation angle of the face plate, and determines that the level of risk of over-uptake is high depending on the frequency at which it is determined that there is a risk of over-uptake when the wavelength is longer or shorter than the reference wavelength during one rotation of the face plate. Means 2 or Means 4 2. The underground radar device according to claim 1,

[0014] Means 7 The determining unit determines that the level of risk of over-intake is high depending on the degree of discretization of the rotational position of the face plate at which it is determined that there is a risk of over-intake. Means 5 or 6 2. The underground radar device according to claim 1,

[0015] Means 8 The determination unit performs a weighting determination depending on the position of the face of the received surface propagation wave. Any of means 1 to 7 1 is a ground penetrating radar device according to the present invention.

[0016] Means 9 The determination unit is characterized in that it weights the received surface propagation waves obtained at the upper part of the face more than those obtained at the lower part of the face. Means 8 2. The underground radar device according to claim 1, [Effects of the Invention]

[0017] According to the present invention, by comparing the propagation time or wavelength of the received surface propagation wave with the reference propagation time or reference wavelength of a surface propagation wave that normally propagates through a soil layer, it is possible to detect the moisture content and the presence or absence of voids in the ground near the front of the face plate, and to determine the intake status of excavated soil at the face.

[0018] In addition, by determining the level of risk of excessive intake depending on the degree of difference between the propagation time or wavelength of the surface propagation wave that becomes an abnormal wave and the reference propagation time or reference wavelength, it is possible to distinguish between high and low risk levels, thereby increasing the safety of excavation work.

[0019] In addition, the propagation time or wavelength of the surface propagating wave at each specified rotation angle of the face plate is compared with the reference propagation time or reference wavelength, and it is determined that the higher the frequency of occurrence of surface propagating waves that become abnormal waves during one rotation of the face plate, the higher the level of risk of excessive intake.This makes it easy to determine whether there are many locations where abnormalities occur in front of the face plate and whether there is a high risk of excessive intake of excavated soil.

[0020] In addition, by weighting the received surface propagation waves obtained above the face more heavily than those below the face, the risk of over-intake can be grasped with greater accuracy. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a front view of an underground excavator according to a first embodiment of the present invention. FIG. [Figure 2] 1 is a block diagram of an underground radar device showing a first embodiment of the present invention. [Figure 3] FIG. 2 is an explanatory diagram of a received wave according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the relationship between the propagation time of a surface propagation wave according to the first embodiment of the present invention. [Figure 5] FIG. 11 is a diagram showing the relationship between the degree of abnormality and the ratio between the propagation time of a surface propagating wave and the propagation time of a surface propagating wave propagating through air according to the third embodiment of the present invention. [Figure 6]FIG. 10 is a diagram showing the relationship between the degree of anomaly and the ratio between the propagation time of a surface propagating wave according to the fourth embodiment of the present invention and the propagation time of a surface propagating wave that propagates through a normal soil layer. [Figure 7] FIG. 13 is a diagram showing the relationship between the rate at which abnormal waves are received and the score according to the fifth embodiment of the present invention. [Figure 8] FIG. 13 is a diagram showing a correction coefficient based on the discreteness of abnormal waves according to the sixth embodiment of the present invention. [Figure 9] FIG. 13 is a diagram showing criteria for determining a degree of risk according to the seventh embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing coefficients based on measurement positions of surface propagating waves according to the eighth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments 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 embodiments.

[0023] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS.

[0024] FIG. 1 is a front view of an underground tunneling machine according to the first embodiment, FIG. 2 is a block diagram of an underground radar device according to the first embodiment, FIG. 3 is an explanatory diagram of received waves according to the first embodiment, and FIG. 4 is a diagram showing the relationship between the propagation times of surface propagating waves. In the following description, the direction of excavation of the underground tunneling machine is referred to as the front, and the opposite direction as the rear.

[0025] 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 with an array of many bits 20a, 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 moves forward while taking in soil through the slits 21.

[0026] An underground radar device 3 is installed on the face plate 2. The underground radar device 3 emits pulsed 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 2 (their paths are shown by arrow H in Figure 2). 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 condition of the soil layer near the surface of the face plate 2. In this embodiment, this underground radar device is used to determine the intake status of excavated soil at the face.

[0027] As shown in FIG. 2, the underground radar device 3 includes a transmitting antenna unit 31, a receiving antenna unit 32, a determining unit 33, and a display unit .

[0028] The transmitting antenna unit 31 and the receiving antenna unit 32 are installed at positions on the front surface of the face plate 2 that avoid the areas where the cutter 20 and the slit 21 are provided. In this embodiment, the transmitting antenna unit 31 and the receiving antenna unit 32 are arranged side by side with a small gap between them in the circumferential direction of the face plate 2, as shown in FIG.

[0029] The transmitting antenna unit 31 is controlled by the transmission control unit 310 to transmit electromagnetic waves of a predetermined frequency. The receiving antenna unit 32 receives the electromagnetic waves transmitted by the transmitting antenna unit 31. As shown in Fig. 3, the electromagnetic waves received by the receiving antenna unit 32 include surface propagating waves and reflected waves that are received later, but the surface propagating waves are used to determine the state of the soil layer near the front surface of the face plate 2.

[0030] The transmitting antenna section 31 transmits electromagnetic waves as appropriate while the face plate 2 is rotating or stopped, and the receiving antenna section 32 receives the electromagnetic waves.

[0031] The determination unit 33 includes a calculation unit 330 , a comparison unit 331 , and a data storage unit 332 . The calculation unit 330 is connected to the transmission control unit 310, the receiving antenna unit 32, and the comparison unit 331, and the comparison unit 331 is connected to the data storage unit 332 and the display unit .

[0032] The judgment unit 33 compares a value based on the propagation time taken from the time of transmission of the received surface propagating wave to the time of reception with a value based on the reference propagation time taken from the time of transmission of the surface propagating wave to the time of reception when propagating through a normal soil layer, and judges that there is a risk of over-intake if the value based on the propagation time is larger than the value based on the reference propagation time or if it is an abnormal wave that is smaller. Specifically, the judgment is made as follows:

[0033] The judgment unit 33 receives a rotation angle signal from a rotation angle detection means (not shown) of the face plate 2 provided on the underground tunneling machine 1, and the surface propagating waves transmitted and received are linked to the corresponding rotation angle of the face plate 2, so that the comparison unit 331 can make a judgment about the surface propagating waves at every predetermined rotation angle of the face plate 2 (every 1 degree in this embodiment). Therefore, when the face plate 2 rotates once from the 0 o'clock direction (0 degrees) to the 12 o'clock direction (360 degrees), the comparison unit 331 can make judgments for 360 degrees (360 times in this embodiment).

[0034] The calculation unit 330 calculates the propagation time taken from the transmission time of the electromagnetic wave obtained from the transmission control unit 310 to the reception time of the surface propagating wave obtained from the receiving antenna unit 32.

[0035] The propagation time t of the surface propagation wave is t=L / v, where L is the distance between the transmitting antenna section 31 and the receiving antenna section 32 and v is the speed of the electromagnetic wave. The velocity v of an electromagnetic wave depends on the relative dielectric constant of the medium through which the electromagnetic wave propagates. The speed of light is C(3.0×10 5 km / sec), then v=C / √ε. Therefore, the propagation time t = √ε × (L / C).

[0036] The relative dielectric constant ε is 16 to 36 for normal soil layers such as sand, loam, and clay, 81 for water, and 1 for air. Therefore, the propagation times of a surface propagating wave through a normal soil layer, water, and air are as follows, respectively:

[0037] Propagation time of normal soil layer ts = (4~6) × (L / C) Propagation time in water tw=9×(L / C) Propagation time in air ta=(L / C)

[0038] Compared to the propagation time ta of a surface propagating wave propagating through the air, the propagation time ts of a surface propagating wave propagating through soil layers is usually 4 to 6 times longer, and the propagation time tw of a surface propagating wave propagating through water is 9 times longer. This relationship is shown in Figure 4. The propagation time is the propagation time of the peak of the received surface propagation wave.

[0039] The data storage unit 332 stores the propagation time ts of a surface propagation wave that normally propagates through a soil layer as a reference propagation time. The calculation unit 330 sends the calculated propagation time of the surface propagation wave to the comparison unit 331 .

[0040] The comparison unit 331 reads out the reference propagation time from the data storage unit 332 and compares this reference propagation time with the propagation time of the surface propagation wave obtained from the calculation unit 330 .

[0041] If the propagation time of the received surface propagation wave is longer than the reference propagation time, it means that the soil layer near the front face (face) of the face plate 2 has more moisture than normal soil layers, and if the propagation time of the received surface propagation wave is shorter than the reference propagation time, it means that there are many voids in the soil layer near the front face (face) of the face plate 2.

[0042] Therefore, in either case, the comparison unit 331 determines that the received surface propagation wave is an abnormal wave and that there is a high risk of excessive intake of excavated earth and sand, and sends the comparison result to the display unit 34 as a danger signal. The comparison unit 331 may make the determination based on a threshold value set in consideration of a predetermined ratio from the reference propagation time.

[0043] The display unit 34 receives the danger signal from the comparison unit 331 and displays that there is a high risk of taking in too much excavated earth and sand. The indication may be a mark indicating which part of the front surface of the base plate 2 is at risk, or a graphic indicating the presence of a cavity or high moisture content.

[0044] Furthermore, the magnification with respect to the reference propagation time, the reference propagation time, the received propagation time, etc. may be displayed. In addition, even during normal times when there is no risk of excessive intake of excavated earth and sand, the display unit 34 may display that the situation is normal.

[0045] The underground radar device 3 determines the intake state of the excavated earth and sand as follows. When the underground tunneling machine 1 starts digging and the face plate 2 rotates, the transmission control unit 310 sends a transmission signal to the transmission antenna unit 31, and the transmission antenna unit 31 receives the transmission signal and emits electromagnetic waves in front of the face plate 2. The transmission control unit 310 sends a transmission signal to the transmitting antenna unit 31 and, at the same time, sends a transmission time to the calculation unit 330 .

[0046] When the receiving antenna section 32 receives a surface propagating wave that has propagated near the front surface of the face plate 2 out of the electromagnetic waves transmitted by the transmitting antenna section 31 , the receiving antenna section 32 sends the reception time to the calculation section 330 . The calculation unit 330 calculates the propagation time of the surface propagating wave based on the transmission time of the electromagnetic wave sent from the transmission control unit 310 and the reception time of the surface propagating wave sent from the receiving antenna unit 32, and sends the calculated propagation time to the comparison unit 331.

[0047] The comparison unit 331 compares the reference propagation time read from the data storage unit 332 with the propagation time of the surface propagation wave sent from the calculation unit 330, and sends a signal to the display unit 34 if the propagation time of the received surface propagation wave is longer or shorter than the reference propagation time. The display unit 34 receives the signal from the comparison unit 331 and displays that there is a high risk of excessive intake of excavated earth and sand.

[0048] The judgment by the comparison unit 331 may be made by displaying all of the values ​​for each predetermined rotation angle of the face plate 2, or by making a judgment and displaying the results after performing statistical processing such as averaging. Also, the judgment may be made when the rotation of the face plate 2 is stopped, i.e., when excavation is stopped.

[0049] In this embodiment, the propagation time ts of the surface propagation wave propagating through a normal soil layer, which is used as the reference propagation time, is set to 4 to 6. However, this is not limited to this, and it may be set based on the soil layer obtained from a preliminary survey or on-site samples. It may also be set for a surface propagation wave in a location that is considered to be a normal soil layer, such as one where excavation was performed without any problems using the previous ring. It is also possible to directly calculate the propagation time of the received surface propagation wave and the reference propagation time by substituting the values ​​of L and C, and then make a judgment.

[0050] Second Embodiment A second embodiment of the present invention will be described below, with the following explanation focusing mainly on the differences and omitting the explanation of the same parts as in the first embodiment.

[0051] The second embodiment differs from the first embodiment in that the state of intake of excavated earth and sand is determined based on the wavelength of the surface propagation wave.

[0052] Since the frequency of the electromagnetic wave transmitted from the transmitting antenna unit 31 is constant and known, if the propagation speed of the surface propagating wave is fast and the propagation time is short, the wavelength will be short, and if the propagation speed of the surface propagating wave is slow and the propagation time is long, the wavelength will be long. Therefore, if the wavelength of a surface propagating wave that normally propagates through soil layers is λs, then the wavelength of a surface propagating wave that propagates through air is λa = 1 / (4~6)λs, and the wavelength of a surface propagating wave that propagates through water is λw = 9 / (4~6)λs. Figure 4 shows an image of these.

[0053] In the second embodiment, the calculation unit 330 calculates the wavelength of the surface propagation wave based on the propagation time required from the time of transmission of the surface propagation wave to the time of reception, and sends the calculated wavelength to the comparison unit 331. The data storage unit 332 stores, as a reference wavelength, a wavelength calculated from the propagation time of a surface propagation wave that normally propagates through a soil layer.

[0054] The comparison unit 331 compares the wavelength of the surface propagating wave calculated by the calculation unit 330 with the reference wavelength read out from the data memory unit 332, and if the wavelength of the surface propagating wave is longer or shorter than the reference wavelength, it determines that the received surface propagating wave is an abnormal wave and there is a risk of excessive intake of excavated soil and sends a danger signal to the display unit 34.

[0055] Third Embodiment The third embodiment of the present invention will be described below, with the same parts as the first and second embodiments being omitted and differences being mainly described.

[0056] The third embodiment differs from the first embodiment in that the risk of excessive uptake is determined in stages depending on the degree of difference between the propagation time of the surface propagation wave and the reference propagation time.

[0057] The propagation time of a surface propagating wave propagating through the air is expressed as L / C, where L is the distance between the antennas, C is the speed of light, and the relative dielectric constant is 1. Then, the propagation time t of the received surface propagating wave can be expressed as t = α × (L / C).

[0058] The calculation unit 330 calculates α from the propagation time of the received surface propagation wave. In the data storage unit 332, a value greater than 4 and equal to or less than 6 is stored as α, which is a value based on the reference propagation time when propagating through a normal soil layer (because the relative dielectric constant of a normal soil layer is set to 16 to 36).

[0059] As shown in FIG. 5, if α calculated by the calculation unit 330 is a value based on the reference propagation time, that is, 4<α≦6, the comparison unit 331 determines that there is no risk of excessive intake of excavated earth and sand. If α is 4 or less, there are voids in the ground, and if it is greater than 6, there is a high moisture content, and in either case there is a risk of excessive absorption of excavated soil and sand.

[0060] If 3<α≦4 or 6<α≦7, the comparison unit 331 determines that the difference from the value based on the reference propagation time is relatively small and the degree of abnormality is low, so the risk of excessive intake of excavated soil is low.

[0061] If 2<α≦3 or 7<α≦8, the difference from the value based on the reference propagation time is medium and the degree of abnormality is medium, so the risk of excessive intake of excavated soil is judged to be at a medium level.

[0062] If α≦2 or 8<α, the difference from the value based on the reference propagation time is large and the degree of abnormality is high, so it is determined that there is a high risk of excessive intake of excavated soil.

[0063] The comparison unit 331 sends a signal to the display unit 34 indicating a score of 1 if the determined risk is low, a score of 2 if it is medium, or a score of 3 if it is high.

[0064] The display unit 34 displays a score indicating whether the risk level is low, medium, or high. Note that the display may not only display the score, but also the degree of abnormality as high, medium, or low, or may display both the score and the degree of abnormality.

[0065] In the case of this embodiment, it is possible to make an absolute evaluation of the propagation time of a surface propagation wave in air.

[0066] In this embodiment, the risk of excessive intake of excavated soil is judged in stages based on the ratio α between the propagation time of the received surface propagation wave and the reference propagation time. However, the level of risk of excessive intake may also be judged by evaluating the degree of difference based on the difference between the propagation time of the received surface propagation wave and the reference propagation time.

[0067] [Fourth embodiment] The fourth embodiment of the present invention will be described below, with the explanation of the same parts as the first to third embodiments being omitted and the differences being mainly described.

[0068] The fourth embodiment differs from the third embodiment in that the risk of excessive intake of excavated soil is determined in stages based on the ratio β between the propagation time of the received surface propagation wave and the propagation time of the surface propagation wave that normally propagates through the soil layer.

[0069] If the propagation time of a surface propagating wave when propagating through a normal soil layer is ts, the propagation time of the received surface propagating wave, t, can be expressed as t = β × ts.

[0070] The calculation unit 330 calculates β based on the propagation time of the received surface propagation wave. The data storage unit 332 stores a value of β that is greater than 0.9 and equal to or less than 1.1 as a value based on the reference propagation time when propagating through a normal soil layer.

[0071] As shown in FIG. 6, if β calculated by the calculation unit 330 is a value based on the reference propagation time, that is, 0.9<β≦1.1, the comparison unit 331 determines that there is no risk of excessive intake of excavated earth and sand. If β is 0.9 or less, there are voids in the ground, and if it is greater than 1.1, there is a high moisture content, and in either case there is a risk of excessive absorption of excavated soil and sand.

[0072] If 0.7<β≦0.9 or 1.1<β≦1.3, the comparison unit 331 determines that the degree of difference from the value based on the reference propagation time is relatively small and the degree of abnormality is low, so the risk of excessive intake of excavated soil and sand is low.

[0073] If 0.5<β≦0.7 or 1.3<β≦1.5, the difference from the value based on the reference propagation time is medium, and the degree of abnormality is medium, so the risk of excessive intake of excavated soil is judged to be at a medium level.

[0074] If β≦0.5 or 1.5<β, the difference from the value based on the reference propagation time is large, and the degree of abnormality is large, so it is determined that there is a high level of risk of excessive intake of excavated soil and sand.

[0075] The comparison unit 331 sends a signal to the display unit 34 indicating a score of 1 if the determined risk is low, a score of 2 if it is medium, or a score of 3 if it is high.

[0076] The display unit 34 displays a score indicating whether the risk level is low, medium, or high. Note that the display may not only display the score, but also the degree of abnormality as high, medium, or low, or may display both the score and the degree of abnormality.

[0077] In this embodiment, it is possible to make a relative evaluation with respect to the propagation time of the surface propagation wave in a normal soil layer.

[0078] In this embodiment, the risk of excessive intake of excavated soil and sand is judged in stages based on the ratio β between the propagation time of the received surface propagating wave and the propagation time of the surface propagating wave that normally propagates through the soil layer. However, the level of risk of excessive intake may also be judged by evaluating the degree of difference based on the difference between the propagation time of the received surface propagating wave and the propagation time of the surface propagating wave that normally propagates through the soil layer.

[0079] Fifth Embodiment The fifth embodiment of the present invention will be described below, with the following explanation focusing mainly on the differences and omitting the explanation of the same parts as the first to fourth embodiments.

[0080] The fifth embodiment differs from the first embodiment in the process of comprehensively determining the propagation times of the surface propagation waves obtained while the face plate 2 makes one rotation.

[0081] While the face plate 2 makes one rotation, transmission and reception are performed by the transmitting antenna section 31 and the receiving antenna section 32, and the comparison section 331 determines whether or not the wave is abnormal, for example, 360 times per degree. The comparison unit 331 determines that the received surface propagation wave is an abnormal wave when the propagation time of the surface propagation wave is longer or shorter than the reference propagation time.

[0082] The ratio γ of the number of times n that an abnormal wave is determined during one rotation of the face plate 2 can be expressed as γ=n / 360.

[0083] As shown in FIG. 7, if γ≦2%, the comparison unit 331 determines that the proportion is extremely low and the score indicating the risk level is 1. If 2%<γ≦5%, the comparison unit 331 determines that the proportion is low and the score is 2. If 5%<γ≦10%, the comparison unit 331 determines that the proportion is medium and the score is 4.

[0084] If 10%<γ≦15%, the comparison unit 331 determines that the proportion is high and gives a score of 8. If 15%<γ, the comparison unit 331 determines that the proportion is extremely high and gives a score of 16.

[0085] The comparison unit 331 sends the evaluated score to the display unit 34, and the display unit 34 displays the risk level of excessive intake of excavated earth and sand using the score sent from the comparison unit 331. Note that the display may not only show the score, but also show the percentage from very low to very high, or may show both the score and the percentage.

[0086] Sixth Embodiment The sixth embodiment of the present invention will be described below, with explanations of parts that are the same as those in the first to fifth embodiments being omitted.

[0087] In the sixth embodiment, the percentage γ of the number of times n that an abnormal wave is determined to be present during one rotation of the face plate 2 in the fifth embodiment is further considered to be discrete, which is the variation in the rotational positions of the face plate at which abnormal waves are detected, and the determination is made by correcting the percentage γ according to this discrete. In other words, even if the percentage γ is the same, if the rotational positions of the face plate at which abnormal waves are detected are closer together, it can be determined to be more dangerous, so the percentage γ is multiplied by a correction coefficient η accordingly to make the determination.

[0088] The judgment unit 33 can judge whether or not a wave is abnormal for each predetermined rotation angle (every degree in this embodiment), and therefore calculates the discretization B of the rotation position of each piece of data judged to be an abnormal wave during one rotation of the panel 2 based on the difference in rotation angle between each abnormal wave.

[0089] As a specific example, it can be determined as follows. B=D / (n*(n-1) / 2) D: Sum of the rotation angle difference between each abnormal wave (*The maximum rotation angle difference is 180 degrees) n: Number of times abnormal waves were detected

[0090] For example, when abnormal waves are detected four times at rotation angles of 10 degrees, 11 degrees, 12 degrees, and 13 degrees, the degree of discretization B is ((11-10) + (12-10) + (13-10) + (12-11) + (13-11) + (13-12)) / (4 × (4-1) / 2) ≒ 2.

[0091] For example, when abnormal waves are detected four times at rotation angles of 10 degrees, 11 degrees, 40 degrees, and 50 degrees, the degree of discretization B is ((11-10) + (40-10) + (50-10) + (40-11) + (50-11) + (50-40)) / (4 × (4-1) / 2) ≈ 25.

[0092] For example, when abnormal waves are detected four times at rotation angles of 10 degrees, 20 degrees, 60 degrees, and 200 degrees, the degree of discretization B is ((20-10) + (60-10) + (360-(200-10)) + (60-20) + (200-20) + (200-40)) / (4 × (4-1) / 2) ≈ 118. In this way, it can be evaluated that the smaller the degree of discreteness B, the more densely abnormal waves are concentrated.

[0093] For the determined discreteness B, thresholds B1, B2, and B3 (B1>B2>B3) are set, for example, and a correction coefficient η is set as shown in Fig. 8. For example, when the determined discreteness B is larger than B1, the correction coefficient η is set to 1; when it is equal to or smaller than B1 and smaller than B2, the correction coefficient η is set to 1.1; when it is equal to or smaller than B2 and smaller than B3, the correction coefficient η is set to 1.3; and when it is equal to or smaller than B3, the correction coefficient η is set to 1.8.

[0094] Then, the determination unit 33 performs a determination on the proportion γ multiplied by the correction coefficient η based on FIG. 7, in the same manner as in the fifth embodiment.

[0095] Seventh Embodiment The seventh embodiment of the present invention will be described below, with explanations of parts that are the same as those of the first to sixth embodiments being omitted.

[0096] In the seventh embodiment, the comparison unit 331 determines the level of risk of excessive intake of excavated soil by the sum of the products of a score (for example, set as shown in Figure 6) that is set in stages according to the ratio β of the propagation time of the received surface propagating wave to the propagation time of a surface propagating wave that normally propagates through a soil layer, and a score (for example, set as shown in Figure 7) that is set in stages according to the proportion γ' that indicates whether the range of the ratio β related to the score appears during one rotation of the face plate 2.

[0097] The risk level can be expressed as C = Σ (β score × γ' score). For example, if during one rotation of the face plate 2, the percentage γ of the state β≦0.5 is 12%, the percentage γ of the state 0.5<β≦0.7 is 7%, and the percentage γ of the state 0.7<β≦0.9 is 4%, then C=3×8+2×4+1×2=34.

[0098] As shown in FIG. 9, if C ≤ 2, the risk level of excessive intake of excavated soil and sand is extremely low; if 2 < C ≤ 6, the risk level is low; if 6 < C ≤ 12, the risk level is moderate; if 12 < C ≤ 24, the risk level is high; if 24 < C, the risk level is extremely high. The comparison unit 331 makes such a judgment and sends the judged risk level to the display unit 34. The display unit 34 displays the risk level sent from the comparison unit 331.

[0099] 〔Eighth Embodiment〕 Hereinafter, the eighth embodiment of the present invention will be described. Descriptions of the same parts as those in the first to seventh embodiments will be omitted.

[0100] In the eighth embodiment, the comparison unit 331 determines the risk level of excessive intake of excavated soil and sand according to the position of the part at the face of the transmission antenna unit 31 and the reception antenna unit 32 where the received surface-propagating wave becomes an abnormal wave during one rotation of the face plate 2. For example, when a cavity is generated in the ground due to excessive intake of excavated soil and sand, the soil and sand will collapse from top to bottom, so it is conceivable that voids or the like will occur above the face. Then, when the surface-propagating wave received when the transmission antenna unit 31 and the reception antenna unit 32 are located at the upper part of the face is abnormal, it can be said that the risk of excessive intake of excavated soil and sand is high.

[0101] FIG. 10 shows the coefficient φ corresponding to the position δ (for example, the midpoint between the transmission antenna unit and the reception antenna unit) of the transmission antenna unit 31 and the reception antenna unit 32 attached to the face plate 2 when the surface-propagating wave is received. When the position δ is located from the 3 o'clock direction to the 9 o'clock direction, the coefficient φ is set to 1; when it is located from the 9 o'clock direction to the 10 o'clock direction and from the 2 o'clock direction to the 3 o'clock direction, the coefficient φ is set to 1.1; when it is located from the 10 o'clock direction to the 2 o'clock direction, the coefficient φ is set to 1.2.

[0102] Then, the degree of abnormality is determined by multiplying (for example, when α is greater than the reference propagation time 6) or dividing (for example, when α is less than the reference propagation time 4) the α and β calculated as in other embodiments by the coefficient φ, and the result is displayed in the same manner. In this way, the determination unit weights and judges abnormalities in the surface propagating waves obtained above the face. In other words, the determination unit weights and judges the received surface propagating waves according to the position of the face.

[0103] [Other Modifications] The present invention is not limited to the above-described embodiment, and may also include the following, for example.

[0104] In this embodiment, the risk of taking in too much excavated earth and sand is displayed on the display unit, but the risk or the level of the risk may be notified by an audio alarm or the like.

[0105] In this embodiment, the underground tunneling machine is a shield tunneling machine used in shield construction, 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 jacking construction or TBM construction.

[0106] In the third to eighth embodiments, the determination is made by comparing the propagation time of the surface propagation wave with the reference propagation time, but the determination may also be made by comparing the wavelength of the surface propagation wave with the reference wavelength.

[0107] In the seventh embodiment, the risk level of excessive intake of excavated soil is determined by the sum of the products of the score of the ratio β of the propagation time of the received surface propagating wave to the propagation time of the surface propagating wave propagating through a normal soil layer and the score of the percentage γ of the number of times abnormal waves are received to the number of times electromagnetic waves are transmitted and received.However, the risk level may also be determined by the sum of the products of the score of the ratio α of the propagation time of the received surface propagating wave to the propagation time of the surface propagating wave propagating through the air and the score of the percentage γ of the number of times abnormal waves are received to the number of times electromagnetic waves are transmitted and received.

[0108] In this embodiment, excessive intake is judged every time the face plate rotates a predetermined angle or every time the face plate rotates once, but this is not limited to this and it may be judged every excavation cycle (for example, every ring in the case of shield construction, and since the face plate rotates multiple times for one ring, the data obtained during that time is subjected to statistical processing such as averaging) and displayed on the display unit.

[0109] In the eighth embodiment, the judgment is made by weighting the upper part of the working face, but the present invention is not limited to this, and weighting may be made to other parts such as the lower part of the working face.

[0110] In this embodiment, the propagation times ta, ts, and tw of the surface propagating waves are set based on the position of the first maximum (peak) of each surface propagating wave ( FIG. 4 ). However, they may also be set based on the position of the minimum. They may also be set based on the midpoint between the maximum and minimum. They may also be set based on the position of the second or subsequent maximum or minimum of each surface propagating wave. They may also be set based on the midpoint between the nth maximum or minimum (including the first) and the n+1th maximum or minimum. They may also be set based on the midpoint between the nth maximum and minimum (including the first).

[0111] Each technical matter in any of the embodiments may be applied to other embodiments to form examples. [Explanation of symbols]

[0112] 1 Underground digging machine 2 face plates 20 Cutter 20a bit 21 Slit 3. Ground-penetrating radar equipment 31 Transmitting antenna section 310 Transmission control section 32 Receiving antenna section 33 Judgment Department 330 Arithmetic section 331 Comparison Section 332 Data storage unit 34 Display section

Claims

1. An underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that has a rotating face plate having a cutter; a receiving antenna unit that receives, of the electromagnetic waves, at least surface propagating waves that propagate through the ground in front of the underground tunneling machine; a determining unit; and a notifying unit, The determination unit compares the propagation time taken from the time of transmission to the time of reception of the received surface propagating wave with a reference propagation time taken from the time of transmission to the time of reception of the surface propagating wave when propagating through a normal soil layer stored as having no risk of over-intake, and determines whether the propagation time is longer or shorter than the reference propagation time; if the propagation time is longer or shorter than the reference propagation time, the determination unit sends out a signal indicating that the received surface propagating wave is an abnormal wave and there is a risk of over-intake; The underground radar device is characterized in that the notification unit receives the signal and issues a notification that there is a risk of over-intake.

2. An underground radar device comprising: a transmitting antenna unit that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that has a rotating face plate having a cutter; a receiving antenna unit that receives, of the electromagnetic waves, at least surface propagating waves that propagate through the ground in front of the underground tunneling machine; a determining unit; and a notifying unit, The determination unit compares the wavelength of the received surface propagating wave with a reference wavelength of the surface propagating wave when propagating through a normal soil layer that has been stored as having no risk of excessive uptake, and determines whether the wavelength is longer or shorter than the reference wavelength. If the wavelength is longer or shorter than the reference wavelength, the determination unit determines that the received surface propagating wave is an abnormal wave and sends out a signal indicating that there is a risk of excessive uptake. The underground radar device is characterized in that the notification unit receives the signal and issues a notification that there is a risk of over-intake.

3. An underground radar device comprising: a transmitting antenna section that transmits electromagnetic waves toward the ground in front of an underground tunneling machine having a rotating face plate with cutters; a receiving antenna section that receives at least surface propagating waves of the electromagnetic waves that propagate through the ground in front of the underground tunneling machine; and a judgment section, The judgment unit compares the propagation time taken from the time of transmission of the received surface propagating wave to the time of reception with a reference propagation time taken from the time of transmission of the surface propagating wave to the time of reception when it normally propagates through a soil layer, and judges whether the propagation time is longer or shorter than the reference propagation time.If the propagation time is longer or shorter than the reference propagation time, the judgment unit calculates the difference between the propagation time and the reference propagation time, and sends out a signal indicating the level of risk of over-intake based on an index set according to the difference.

4. An underground radar device comprising: a transmitting antenna section that transmits electromagnetic waves toward the ground in front of an underground tunneling machine that has a rotating face plate having a cutter; a receiving antenna section that receives at least surface propagating waves of the electromagnetic waves that propagate through the ground in front of the underground tunneling machine; and a judgment section, The judgment unit compares the wavelength of the received surface propagating wave with a reference wavelength of the surface propagating wave when it normally propagates through a soil layer, and judges whether the wavelength is longer or shorter than the reference wavelength. If the wavelength is longer or shorter than the reference wavelength, the judgment unit calculates the difference between the wavelength and the reference wavelength, and sends out a signal indicating the level of risk of over-intake based on an index set according to the difference.

5. An underground radar device comprising: a transmitting antenna section that transmits electromagnetic waves toward the ground in front of an underground tunneling machine having a rotating face plate with cutters; a receiving antenna section that receives at least surface propagating waves of the electromagnetic waves that propagate through the ground in front of the underground tunneling machine; and a judgment section, The judgment unit compares the propagation time taken from the time of transmission to the time of reception of the received surface propagating wave for each predetermined rotation angle of the face plate with a reference propagation time taken from the time of transmission to the time of reception of the surface propagating wave when it propagates through a normal soil layer, and judges whether the propagation time is longer or shorter than the reference propagation time.If the propagation time is longer or shorter than the reference propagation time, the received surface propagating wave is determined to be an abnormal wave, the frequency of the abnormal waves during the predetermined rotation of the face plate is identified, and a signal indicating the level of risk of over-intake is sent out based on an index set according to the frequency.

6. An underground radar device comprising: a transmitting antenna section that transmits electromagnetic waves toward the ground in front of an underground tunneling machine having a rotating face plate with cutters; a receiving antenna section that receives at least surface propagating waves of the electromagnetic waves that propagate through the ground in front of the underground tunneling machine; and a judgment section, The judgment unit compares the wavelength of the received surface propagating wave at each predetermined rotation angle of the face plate with a reference wavelength of the surface propagating wave when it propagates through a normal soil layer, and judges whether the wavelength is longer or shorter than the reference wavelength.If the wavelength is longer or shorter than the reference wavelength, the received surface propagating wave is determined to be an abnormal wave, identifies the frequency of the abnormal wave during the predetermined rotation of the face plate, and sends out a signal indicating the level of risk of over-intake based on an index set according to the frequency.

7. 7. The underground radar device according to claim 5, wherein the determination unit determines a degree of discretization of the rotational position of the face plate that causes the abnormal wave during a predetermined rotation of the face plate, corrects the frequency of the abnormal wave by a correction coefficient set in accordance with the degree of discretization, and sends out a signal indicating a level of risk of over-intake based on an index set in accordance with the frequency.

8. 8. The underground radar device according to claim 5, wherein the judgment unit specifies a weighting coefficient of abnormality set according to the position of the face at which the received surface propagating wave is determined to be an abnormal wave, and sends out a signal indicating the level of risk of over-intake based on the index set also based on the weighting coefficient.

9. An underground radar device as described in Claim 8, characterized in that the weighting coefficients are set so that those at the upper part of the face are weighted more heavily than those at the lower part of the face.

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