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 radio wave intensity V of the received surface propagation wave and reference radio wave intensity Vs0 of a surface propagation wave propagating along a normal soil layer, and determines the presence of a risk of excessive extraction when the radio wave intensity V is greater or smaller than the reference radio wave intensity Vs0.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 occur, it affects the radio wave intensity of the surface propagating waves that pass through this part. For example, when the moisture content increases, the surface propagating waves are attenuated more as they propagate than in a normal soil layer, and the radio wave intensity of the electromagnetic waves received by the receiving antenna is weaker than in a normal soil layer. The inventors discovered that when there are a large number of air bubbles or cavities, the attenuation of the surface propagating waves is reduced as they propagate compared to a normal soil layer, and the radio wave intensity of the electromagnetic waves received by the receiving antenna is stronger than in a normal soil layer. Based on this knowledge, the inventors have come to use an underground radar device for determining soil quality to determine whether or not 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 the 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 an evaluation value related to the radio wave strength of the received surface propagating waves with an evaluation reference value related to the reference radio wave strength of surface propagating waves when they propagate through a normal soil layer that has been stored as not being at risk of over-intake, and judges whether the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength, and if the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength, it sends out a signal indicating that the received surface propagating waves are abnormal waves and there is a risk of over-intake, and the alarm unit receives the signal and issues an alarm indicating 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 has 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 an evaluation value related to the radio wave strength of the received surface propagating waves with an evaluation reference value related to a reference radio wave strength of surface propagating waves when propagating through a normal soil layer, and judges whether the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength, and if the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength, calculates the difference between the evaluation value related to the radio wave strength and the evaluation reference value related to the reference radio wave strength, 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 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, for each predetermined rotation angle of the face plate, an evaluation value related to the radio wave strength of the received surface propagating waves with an evaluation reference value related to the reference radio wave strength of surface propagating waves when propagating through a normal soil layer, and judges whether the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength, and if the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength, it determines that the received surface propagating waves are abnormal waves, specifies the frequency of the abnormal waves 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 4 is the underground radar device according to claim 3, characterized in that the judgment unit determines 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 5 is an underground radar device according to claim 3 or claim 4, characterized in that the judgment unit identifies 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. The invention of claim 6 is an underground radar device as described in claim 5, 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 another 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 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 an evaluation value related to the radio wave strength of the received surface propagating waves with an evaluation reference value related to the reference radio wave strength of surface propagating waves when they propagate through a normal soil layer, and determines that there is a risk of over-intake if the evaluation value related to the radio wave strength is greater than or less than the evaluation reference value related to the reference radio wave strength.

[0009] Means 2 The determination unit determines the level of risk of overloading depending on the degree of difference between the evaluation value related to the radio wave strength and the evaluation reference value related to the reference radio wave strength. Means 1 2. The underground radar device according to claim 1,

[0010] Means 3 the determination unit compares the evaluation value of the radio wave strength with the evaluation reference value of the reference radio wave strength for each predetermined rotation angle of the face plate, and when the evaluation value of the radio wave strength is greater than or smaller than the evaluation reference value of the reference radio wave strength during one rotation of the face plate, determines that the level of the risk of over-intake is high depending on the frequency at which it has been determined that there is a risk of over-intake. Means 1 or Means 2 2. The underground radar device according to claim 1,

[0011] Means 4 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 3 2. The underground radar device according to claim 1,

[0012] Means 5The determination unit performs a weighting determination depending on the position of the face of the received surface propagation wave. Any of means 1 to 4 1 is a ground penetrating radar device according to the present invention.

[0013] Means 6 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 5 2. The underground radar device according to claim 1, [Effects of the Invention]

[0014] According to the present invention, by comparing the evaluation value relating to the radio wave intensity of the received surface propagating wave with the evaluation reference value relating to the reference radio wave intensity of the surface propagating wave that normally propagates through the 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 the excavated soil at the face.

[0015] In addition, by determining the level of risk of excessive intake depending on the degree of difference between the evaluation value for the radio wave strength of surface propagating waves that become abnormal waves and the evaluation reference value for the reference radio wave strength, it is possible to distinguish between high and low risk levels, thereby increasing the safety of excavation work.

[0016] In addition, the evaluation value relating to the radio wave intensity of the surface propagating wave for each specified rotation angle of the face plate is compared with the evaluation standard value relating to the reference radio wave intensity, 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.

[0017] 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]

[0018] [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. 3 is a diagram showing the relationship between the radio wave intensity of a surface propagating wave according to the first embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing the relationship between the degree of anomaly and the score based on the difference between the propagation strength of a surface propagation wave and the standard radio wave strength according to the second embodiment of the present invention. [Figure 6] FIG. 11 is a diagram showing the relationship between the degree of abnormality and the score based on the ratio between the evaluation value based on the propagation strength of the surface propagation wave and the evaluation reference value based on the standard radio wave intensity according to the fourth embodiment of the present invention. [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

[0019] 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.

[0020] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS.

[0021] 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 radio wave intensity 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.

[0022] 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.

[0023] 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 strength of the surface propagating waves is 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.

[0024] 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 .

[0025] 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.

[0026] The transmitting antenna unit 31 is controlled by the transmission control unit 310 to transmit electromagnetic waves of a predetermined frequency and a predetermined voltage. 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.

[0027] 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.

[0028] 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 .

[0029] The judgment unit 33 compares the radio wave strength (amplitude) of the received surface propagating wave with a reference radio wave strength (amplitude), which is the radio wave strength (amplitude) of a surface propagating wave when it propagates through a normal soil layer, and judges that there is a risk of over-intake if the radio wave strength is greater than the reference radio wave strength or is an abnormal wave that is smaller than the reference radio wave strength. The radio wave intensity of the received surface propagating wave corresponds to the evaluation value for radio wave intensity in the present invention, and the reference radio wave intensity, which is the radio wave intensity of the surface propagating wave when propagating through a normal soil layer, corresponds to the evaluation reference value for radio wave intensity in the present invention. Specifically, the judgment is made as follows:

[0030] 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).

[0031] The calculation unit 330 calculates the radio wave intensity of the surface propagation wave received from the receiving antenna unit 32 .

[0032] The radio wave intensity V of the surface propagation wave obtained from the receiving antenna unit 32 is expressed as V=V0×e, where L is the distance between the transmitting antenna unit 31 and the receiving antenna unit 32, V0 is the transmitted radio wave intensity of the transmitted electromagnetic wave, ε is the relative permittivity of the medium through which the electromagnetic wave propagates, and σ is the conductivity of the medium. (-αL) This becomes: Here, α=60π×√ε×σ.

[0033] The relative dielectric constant ε is found to be approximately εs = 16 to 36 for normal soil layers such as sand, loam, and clay, εw = 81 for water, and εa = 1 for air. In addition, the conductivity σ of air is σa = (3~8) × 10 -15 S / m, and σw=10 for soil water -2 ~10 -1 S / m is recognized, and σs=10 for wet sandy and clayey soils. -2 ~10 -1 S / m.

[0034] If the radio wave intensity of the surface propagation wave in a normal soil layer is Vs, Vs=V0×e (-αSL) αs=60π×√εs×σs If the radio wave intensity of the surface propagation wave in the over-entrainment state a (underwater) is Vw, Vw=V0×e (-αwL) αw=60π×√εw×σw If the radio wave intensity of the surface propagating wave in the overload state b (in air) is Va, Va=V0×e (-αaL) It can be expressed as αa=60π×√εa×σa.

[0035] Then, assuming that the distance between the transmitting antenna unit 31 and the receiving antenna unit 32 is constant at L and the transmitted electromagnetic wave intensity at V0, and substituting the relative permittivities εs, εw, εa and the conductivities σs, σw, σa of the normal soil layer, water, and air, respectively, V0×e (-αwL) <V0×e (-αSL) <V0×e (-αaL) And Vw <Vs<Vaとなる。 That is, the radio wave intensity Vs of a surface propagating wave propagating through a normal soil layer is stronger than the radio wave intensity Vw of a surface propagating wave propagating through water, but weaker than the radio wave intensity Va of a surface propagating wave propagating through air. This relationship is shown in Figure 4. Note that the radio wave intensity (amplitude) is the peak radio wave intensity of the received surface propagation wave.

[0036] The radio wave strength Vs of surface propagating waves that propagate through soil layers is normally expected to have a range, but this Vs is used as the reference radio wave strength Vs0 (evaluation standard value for radio wave strength), which serves as the judgment standard.When the radio wave strength V (evaluation value for radio wave strength) of the received surface propagating waves is smaller than the evaluation standard value Vs0 for radio wave strength, it means that there is a tendency for cavities to be generated in the water due to excessive absorption, and when the radio wave strength V (evaluation value for radio wave strength) of the received surface propagating waves is greater than the evaluation standard value Vs0 for radio wave strength, it means that there is a tendency for cavities to be generated in the air due to excessive absorption.

[0037] The reference radio wave strength Vs0 is stored in the data storage unit 332. The reference radio wave strength Vs0 may be set in advance, or may be calculated by the calculation unit 330 based on the transmitted radio wave strength. The calculation unit 330 sends the calculated radio wave intensity of the received surface propagation wave to the comparison unit 331.

[0038] The comparison unit 331 reads out the reference radio wave intensity Vs0 from the data storage unit 332, and compares this value with the radio wave intensity of the received surface propagation wave obtained from the calculation unit 330.

[0039] If the radio wave intensity of the received surface propagating wave is smaller than the reference radio wave intensity Vs0, the comparison unit 331 determines that the soil layer near the front face (face) of the face plate 2 has more moisture than normal soil layers and that there is a tendency for underwater cavities to occur, and if the radio wave intensity of the received surface propagating wave is larger than the reference radio wave intensity Vs0, it determines that the soil layer near the front face (face) of the face plate 2 has more voids and that there is a tendency for cavities to occur in the air.

[0040] 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 a judgment based on a threshold value set in consideration of a predetermined ratio from the reference radio wave intensity.

[0041] 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.

[0042] Also, a magnification factor for the reference radio wave intensity 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.

[0043] 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 transmission antenna unit 31 , and the transmission antenna unit 31 transmits an electromagnetic wave to the front of the face plate 2 .

[0044] The receiving antenna section 32 receives, of the electromagnetic waves transmitted by the transmitting antenna section 31, surface propagating waves that have propagated near the front surface of the face plate 2. The calculation unit 330 calculates the radio wave intensity of the received surface propagation wave and sends it to the comparison unit 331.

[0045] The comparison unit 331 compares the reference radio wave intensity read from the data storage unit 332 with the radio wave intensity of the surface propagating wave sent from the calculation unit 330, and if the radio wave intensity of the received surface propagating wave is greater than or less than the reference radio wave intensity, it sends a signal indicating an abnormality to the display unit 34. 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.

[0046] 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.

[0047] Since the relative permittivity and conductivity of the excavated soil layer vary depending on the type of soil and groundwater, it is desirable to measure them using samples obtained in a preliminary survey or on-site and reflect these values.In addition, the radio wave strength of the surface propagation wave at 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, may be set as the reference radio wave strength.

[0048] 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.

[0049] In the second embodiment, the level of risk of excessive intake is determined according to the degree of difference between the radio wave intensity of the received surface propagating wave and the reference radio wave intensity. Specifically, the determination is made based on FIG.

[0050] FIG. 5 shows the magnitude of the difference between the received radio wave intensity V of the surface-propagating wave and the reference radio wave intensity Vs0, the degree of abnormality, and the score thereof. The reference radio wave intensity Vs0 has a range from Vs0min to Vs0max, and A is used to divide the level of the radio wave intensity V -2 A -1 A +1 A +2 The values of are Vw ≦ A -2 < A -1 < Vs0min < Vs0max < A +1 < A +2 ≦ Va and are set and stored in the data storage unit 332.

[0051] If the radio wave intensity V of the received surface-propagating wave is Vs0min ≦ V ≦ Vs0max, the comparison unit 331 determines that there is no risk of excessive intake of excavated earth and sand. If V is smaller than Vs0min, a large amount of moisture is present and cavities are generated in water. If V is larger than Vs0max, cavities are generated in air. In either case, the comparison unit 331 determines that there is a risk of excessive intake of excavated earth and sand.

[0052] When V is -1 < V < Vs0min or, when Vs0max < V < +1 the difference from the reference radio wave intensity Vs0 is relatively small and the degree of abnormality is low. Therefore, the comparison unit 331 determines that the risk of excessive intake of excavated earth and sand is at a low level.

[0053] When A -2 < V ≦ A -1 or, when A +1 ≦ V < A +2 the difference from the reference radio wave intensity Vs0 is moderate and the degree of abnormality is moderate. Therefore, the comparison unit 331 determines that the risk of excessive intake of excavated earth and sand is at a medium level.

[0054] When V ≦ A -2 or, when A +2 ≦ V, the difference from the reference radio wave intensity Vs0 is large and the degree of abnormality is large. Therefore, the comparison unit 331 determines that the risk of excessive intake of excavated earth and sand is at a high level.

[0055] 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.

[0056] The display unit 34 displays whether the level of risk is low, medium, or high using a score. 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.

[0057] In this embodiment, the level of risk of excessive uptake is determined according to the magnitude of the difference between the radio wave intensity V of the received surface propagating wave and the reference radio wave intensity Vs0. However, the level of risk of excessive uptake may also be determined by evaluating the degree of difference based on the ratio between the radio wave intensity V of the received surface propagating wave and the reference radio wave intensity Vs0.

[0058] Third Embodiment The third embodiment of the present invention will be described below, with the explanation of the same parts as the first and second embodiments being omitted and the differences being mainly described.

[0059] In the third embodiment, the radio wave intensity of the received surface propagating wave is not directly compared with the reference radio wave intensity (amplitude) of the surface propagating wave when it propagates through a normal soil layer, but is evaluated using an evaluation value based on the radio wave intensity of the received surface propagating wave, which can be expressed in terms of the relative dielectric constant and the conductivity, and an evaluation reference value based on the reference radio wave intensity of the surface propagating wave when it propagates through a normal soil layer. The evaluation value based on the radio wave intensity of the received surface propagating wave corresponds to the evaluation value related to the radio wave intensity in this invention, and the evaluation standard value based on the reference radio wave intensity, which is the radio wave intensity of the surface propagating wave when it normally propagates through a soil layer, corresponds to the evaluation standard value related to the radio wave intensity in this invention.

[0060] The judgment unit 33 compares the evaluation value based on the radio wave intensity (amplitude) of the received surface propagating wave with an evaluation standard value based on the reference radio wave intensity (amplitude) of the surface propagating wave when it propagates through a normal soil layer, and judges that there is a risk of over-intake if the evaluation value based on the radio wave intensity is greater than the evaluation standard value based on the reference radio wave intensity or if it is an abnormal wave that is smaller than the evaluation standard value based on the reference radio wave intensity. Specifically, the judgment is made as follows:

[0061] The radio wave intensity V of the surface propagation wave obtained from the receiving antenna unit 32 is expressed as V=V0×e, where L is the distance between the transmitting antenna unit 31 and the receiving antenna unit 32, V0 is the transmitted radio wave intensity of the transmitted electromagnetic wave, ε is the relative permittivity of the medium through which the electromagnetic wave propagates, and σ is the conductivity of the medium. (-αL) , α=60π×√ε×σ.

[0062] V=V0×e (-αL) Dividing by the transmitted signal strength V0 and taking the logarithm, ln(V / V0)=(-αL) Since α=60π×√ε×σ, ln(V / V0)=-(60π×√ε×σ×L) Transformed ln(V / V0) / (-60πL)=√ε×σ(=F (evaluation value based on radio wave strength)) The following relationship holds: Since the transmitted radio wave intensity V0 and the distance L between the transmitting antenna unit 31 and the receiving antenna unit 32 are known, the value of the relationship between the relative permittivity and conductivity, which represents the state of the front surface of the faceplate through which the surface propagating wave passes, can be found from the value represented by the received radio wave intensity V (which will be referred to as the evaluation value F based on the radio wave intensity).

[0063] Regarding the evaluation value F based on radio wave intensity, if the evaluation value based on the radio wave intensity Vs of the surface propagation wave in a normal soil layer is Fs, then: Fs=ln(Vs / V0) / (-60πL)=√εs×σs If the evaluation value based on the radio wave intensity Vw of the surface propagation wave in the over-entrainment state a (underwater) is Fw, then Fw=ln(Vw / V0) / (-60πL)=√εw×σw If the evaluation value based on the radio wave intensity Va of the surface propagation wave in the over-entrainment state b (in the air) is Fa, then It can be expressed as Fa=ln(Va / V0) / (-60πL)=√εa×σa.

[0064] The relative permittivity of the normal soil layer, water, and air is εs = 16 to 36, εw = 81, εa = 1, and the conductivity is σs = 10 -2 ~10 -1 ≒0.1, σw=10 -2 ~10 -1 ≒0.1, σa=(3~8)×10 -15 If we substitute ≒0, Fs = (4 to 6) x 0.1 = 0.4 to 0.6 Fw=9×0.1=0.9 Since Fa=1×0=0, Fa <Fs<Fwとなる。 In other words, the evaluation value Fs based on the radio wave intensity Vs of a surface propagating wave that propagates through a normal soil layer is greater than the evaluation value Fa based on the radio wave intensity Va of a surface propagating wave that propagates through the air, and is smaller than the evaluation value Fw based on the radio wave intensity Vw of a surface propagating wave that propagates through water.

[0065] The evaluation value Fs based on the radio wave strength Vs of surface propagating waves that propagate through soil layers is normally expected to have a range, but this Fs is used as the evaluation standard value Fs0 (evaluation standard value related to radio wave strength) based on the reference radio wave strength, which is the judgment standard.When the evaluation value F (evaluation value related to radio wave strength) based on the radio wave strength of the received surface propagating waves is smaller than the evaluation standard value Fs0 related to radio wave strength, it means that there is a tendency for cavities to be generated in the air due to excessive absorption, and when the evaluation value F (evaluation value related to radio wave strength) based on the radio wave strength of the received surface propagating waves is larger than the evaluation standard value Fs0 related to radio wave strength, it means that there is a tendency for cavities to be generated in the water due to excessive absorption.

[0066] An evaluation reference value Fs0 based on radio wave strength is stored in the data storage unit 332. The evaluation reference value Fs0 based on radio wave strength may be set in advance or may be calculated by the calculation unit 330.

[0067] As in the first embodiment, the relative permittivity and conductivity of the excavated soil layer vary depending on the type of soil and groundwater, so it is desirable to measure them using samples obtained in a preliminary survey or on-site and reflect the values.Fs0 may also be set as the evaluation reference value based on the radio wave intensity based on the radio wave intensity of the surface propagating waves in a location that is considered to be a normal soil layer, such as one where excavation was performed without any problems using the front ring.

[0068] The calculation unit 330 calculates an evaluation value F based on the radio wave strength from the transmitted radio wave strength V0, the distance L between the transmitting antenna unit 31 and the receiving antenna unit 32, and the radio wave strength of the received surface propagating wave, and sends it to the comparison unit 331.

[0069] The comparison unit 331 reads out the evaluation reference value Fs0 based on the radio wave intensity from the data storage unit 332, and compares this value with the evaluation value F based on the radio wave intensity of the received surface propagation wave obtained from the calculation unit 330.

[0070] If the comparison unit 331 determines that the evaluation value F based on the radio wave intensity of the received surface propagating wave is smaller than the evaluation reference value Fs0, it determines that there are many voids in the soil layer near the front face (face) of the face plate 2 and that cavities in the air tend to be occurring, and if the evaluation value F based on the radio wave intensity of the received surface propagating wave is larger than the evaluation reference value Fs0, it determines that the soil layer near the front face (face) of the face plate 2 has more moisture than normal soil layers and that there is a tendency for cavities in the water to be occurring.

[0071] The subsequent processing is the same as in the first embodiment, and the modified example can be modified in the same way as in the first embodiment. Furthermore, in this embodiment, as in the second embodiment, the level of risk of excessive intake may be determined depending on the degree of difference between the evaluation value F based on the radio wave intensity of the received surface propagating wave and the evaluation reference value Fs0.

[0072] [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.

[0073] The fourth embodiment differs from the third embodiment in that the risk of excessive intake of excavated soil is judged in stages based on the ratio β of the evaluation value F based on the radio wave intensity V of the received surface propagating wave to the evaluation reference value Fs0 based on the reference radio wave intensity Vs0.

[0074] The evaluation value F based on the radio wave intensity V of the received surface propagating wave can be expressed as F=β×Fs0, using an evaluation reference value Fs0 based on the reference radio wave intensity Vs0. The calculation unit 330 calculates β=F / Fs0 based on the radio wave intensity of the received surface propagating wave. As mentioned above, Fs = (4 to 6) x 0.1 = 0.4 to 0.6 Fw=9×0.1=0.9 Since Fa=1×0=0, Based on the range of β stored in the data storage unit 332, such as that shown in FIG.

[0075] If β calculated by the calculation unit 330 is 0.8<β≦1.2, the comparison unit 331 determines that there is no risk of excessive intake of excavated earth and sand. If β is 0.8 or less, there are voids in the ground, and if it is greater than 1.2, there is a high moisture content, and in either case there is a risk of excessive absorption of excavated soil and sand.

[0076] If 0.7<β≦0.8 or 1.2<β≦1.3, the comparison unit 331 determines that the risk of excessive intake of excavated soil is low because the difference from the evaluation reference value based on the reference radio wave intensity is relatively small and the degree of abnormality is low.

[0077] If 0.5<β≦0.7 or 1.3<β≦1.5, the difference from the evaluation standard value based on the reference radio wave intensity 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.

[0078] If β≦0.5 or 1.5<β, the difference from the evaluation reference value based on the reference radio wave intensity 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 and sand.

[0079] 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.

[0080] The display unit 34 displays whether the level of risk is low, medium, or high using a score. 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.

[0081] In this embodiment, the risk of excessive intake of excavated soil is judged in stages based on the ratio β of the evaluation value F based on the radio wave intensity V of the received surface propagating wave and the evaluation standard value Fs0 based on the reference radio wave intensity Vs0. However, the level of risk of excessive intake may also be judged by evaluating the degree of difference based on the difference between the evaluation value F based on the radio wave intensity V of the received surface propagating wave and the evaluation standard value Fs0 based on the reference radio wave intensity Vs0.

[0082] 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.

[0083] The fifth embodiment differs from the previous embodiments in the process of comprehensively determining the evaluation values ​​relating to the radio wave intensity of each surface propagation wave obtained while the face plate 2 makes one rotation.

[0084] 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 propagating wave is an abnormal wave when the evaluation value (V or F) related to the radio wave strength of the surface propagating wave is greater than or smaller than the evaluation reference value (Vs0 or Fs0) related to the reference radio wave strength.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] In the sixth embodiment, the percentage γ of the number of times n that abnormal waves are 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 2 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 2 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.

[0091] 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.

[0092] 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

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] In the seventh embodiment, the comparison unit 331 determines the level of risk of excessive intake of excavated soil and sand by the sum of the products of the score (for example, set as shown in Figure 6) which is set in stages according to the ratio β of the evaluation value related to the radio wave intensity of the received surface propagating wave to the evaluation reference value related to the reference radio wave intensity for each rotation of the face plate 2, and the score (for example, set as shown in Figure 7) which is set in stages according to the rate γ' at which abnormal waves related to the score appear during one rotation of the face plate 2.

[0100] 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≦0.8 is 4%, then C=3×8+2×4+1×2=34.

[0101] As shown in FIG. 9, if C≦2, the risk level of excessive intake of excavated earth 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 determination and sends the determined risk level to the display unit 34. The display unit 34 displays the risk level sent from the comparison unit 331.

[0102] 〔Eighth Embodiment〕 Hereinafter, the eighth embodiment according to the present invention will be described. Descriptions of parts similar to those in the first to seventh embodiments will be omitted.

[0103] In the eighth embodiment, the comparison unit 331 determines the risk level of excessive intake of excavated earth and sand according to the position of the parts at the face of the transmitting antenna unit 31 and the receiving antenna unit 32 where the received surface wave becomes an abnormal wave during one rotation of the face plate 2. For example, when a cavity is formed in the ground due to excessive intake of excavated earth and sand, the earth and sand collapses from top to bottom, so it is conceivable that voids or the like will occur above the face. Then, when the surface wave received when the transmitting antenna unit 31 and the receiving 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 earth and sand is high.

[0104] FIG. 10 shows the coefficient φ corresponding to the position δ (for example, the midpoint between the transmitting antenna unit and the receiving antenna unit) of the transmitting antenna unit 31 and the receiving antenna unit 32 attached to the face plate 2 when the surface 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.

[0105] Then, the β calculated as in the other embodiments is multiplied by a coefficient φ (for example, when the radio wave strength is greater than the reference radio wave strength) or divided by it (for example, when the radio wave strength is less than the reference radio wave strength) to determine the degree of abnormality and display it in the same way. In this way, the determination unit weights and judges abnormalities in the surface propagation waves obtained above the face. In other words, the determination unit weights and judges the received surface propagation waves according to the position of the face.

[0106] [Other Modifications] The present invention is not limited to the above-described embodiment, and may also include the following, for example.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] In this embodiment, the radio wave intensities Va, Vs, and Vw 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).

[0112] Each technical matter in any of the embodiments may be applied to other embodiments to form examples. [Explanation of symbols]

[0113] 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 an evaluation value relating to the radio wave intensity of the received surface propagating wave with an evaluation reference value relating to the reference radio wave intensity of the surface propagating wave when propagating through a normal soil layer that has been stored as having no risk of over-intake, and determines whether the evaluation value relating to the radio wave intensity is greater than or smaller than the evaluation reference value relating to the reference radio wave intensity. If the evaluation value relating to the radio wave intensity is greater than or smaller than the evaluation reference value relating to the reference radio wave intensity, 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 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 an evaluation value relating to the radio wave strength of the received surface propagating wave with an evaluation reference value relating to the reference radio wave strength of the surface propagating wave when it propagates through a normal soil layer, and judges whether the evaluation value relating to the radio wave strength is greater than or less than the evaluation reference value relating to the reference radio wave strength. If the evaluation value relating to the radio wave strength is greater than or less than the evaluation reference value relating to the reference radio wave strength, the judgment unit calculates the difference between the evaluation value relating to the radio wave strength and the evaluation reference value relating to the reference radio wave strength, and sends out a signal indicating the level of risk of over-intake based on an index set according to the difference.

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 an evaluation value relating to the radio wave strength of the received surface propagating wave for each predetermined rotation angle of the face plate with an evaluation reference value relating to the reference radio wave strength of the surface propagating wave when propagating through a normal soil layer, and judges whether the evaluation value relating to the radio wave strength is greater than or less than the evaluation reference value relating to the reference radio wave strength.If the evaluation value relating to the radio wave strength is greater than or less than the evaluation reference value relating to the reference radio wave strength, the received surface propagating wave is determined to be an abnormal wave, the frequency of the abnormal wave 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.

4. 4. The underground radar device according to claim 3, wherein the determination unit determines the degree of discretization of the rotational position of the face plate that caused the abnormal wave during a predetermined rotation of the face plate, corrects the frequency of the abnormal wave using a correction coefficient set in accordance with the degree of discretization, and sends out a signal indicating the level of risk of over-intake based on an index set in accordance with the frequency.

5. 5. The underground radar device according to claim 3, wherein the determination 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.

6. An underground radar device as described in Claim 5, 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.

Images