JPH0754254B2 - Horizontal displacement measuring device for underground excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to the promotion of an underground excavator for tunnel excavation to bury a water pipe, a gas pipe, etc., according to a construction plan line. The present invention relates to a measuring device for an underground excavator that measures horizontal displacement of the intermediate excavator in the ground.

[Conventional technology]

Conventionally, in underground excavators with a relatively small diameter for the purpose of burying such water pipes and gas pipes, the excavation position is small because the excavation space is small and curved excavation is often performed. In order to measure and confirm, optical survey using laser transit etc. cannot be applied,
In particular, it was impossible to accurately measure the horizontal displacement. On the other hand, recently, a magnetism generating element was installed inside the underground excavator, and by utilizing the characteristics of the alternating magnetic field generated from this magnetometer on the surface of the earth, the ground point directly above or above the underground excavator was used. The method of measuring the displacement from the ground surface point is Japanese Patent Publication Sho 58-1103.
0 Several proposals have been made based on the title of the invention, "Horizontal position detection method for shield machine".

[Problems to be solved by the invention]

According to such a method, it is possible to measure the horizontal position of the underground excavator with certainty, but in this practical use, a probe equipped with the above magnetic detection element in a predetermined posture is used as a target point on the surface of the earth. Since it has to be transported to, installed and explored,
New problems such as taking time will occur. In addition, such a measuring method is almost impossible on a road with a large amount of traffic, and the frequent advantages of the method of burying a pipe using an underground excavator lose the original advantage when it comes to frequent traffic interruptions.

[Means and Actions for Solving Problems]

In the present invention, the magnetic field generating cable is laid on the ground surface so that the forward route and the return route are located at equal intervals from each other according to the construction plan line of the underground excavator, and on the side of the underground excavator. An appropriate magnetic field detecting element is provided so that the magnetic field generated by the cable can be detected. In such a case, these magnetic fields have, for example, different level ratios in the right half direction and the left half direction with the vertical plane of the above-mentioned construction planning line (center line of the reciprocating path cable) as a boundary. Is determined based on the output of the magnetic field detecting element, whether the underground excavator is on the right side or the left side of the vertical plane of the cable, the horizontal displacement mode is effectively and in real time. It is possible to continuously identify and measure.

〔The invention's effect〕

Thus, according to the present invention, by simply laying a magnetic field generating cable in advance on the ground surface according to the construction planning line, accurate data on the horizontal displacement mode of the underground excavator from the construction planning line can be obtained. Can be continuously obtained in real time. Therefore, as long as the above cables are protected against the passage of vehicles, there is no need to interrupt the traffic at all, and the continuous excavation of the above-mentioned data will enable continuous control of the underground excavator. If this is done, the construction accuracy will be greatly improved.

〔Example〕

First, the principle of the present invention will be described with reference to FIGS. 5 and 6.

Now, as shown in FIG. 5, if a magnetic field generating cable 10 composed of a forward route 10a and a backward route 10b, which are separated from each other by a predetermined distance, is laid on the ground surface EP, and an appropriate electric current is applied to the cable, the cable is generated. Magnetic fields Ha and Hb are generated concentrically around the 10 round-trip lines 10a and 10b in the manner shown in FIG. In the present invention, the magnetic fields Ha and Hb thus generated are separated by two magnetic field detecting elements as shown in FIG.
Simultaneously detect S1 and S2. Here, for simplification, it is assumed that the two magnetic field detection elements S1 and S2 have their magnetic field detection directions orthogonal to each other and are maintained at an angle of 45 degrees with respect to the vertical plane of the cable 10.
Under such conditions, each parameter is set as shown in FIG.
That is, L: distance between the round trip lines of the magnetic field generation cable 10 D: depth of the magnetic field detection elements S1 and S2 r ₁ , r ₂ : from the magnetic field generation cable 10 to the magnetic field detection elements S1 and S2
Distance X: Horizontal displacement of the magnetic field detection elements S1 and S2 from the center of the round trip cable (construction planning line PL) X ₁ : Horizontal displacement of the magnetic field detection elements S1 and S2 from the cable return line 10b X ₂ : Magnetic field detection horizontal displacement theta ₁ from the cable forward line 10a of the elements S1 and S2: the vertical plane around a cable recovery line 10b and the magnetic field detecting elements S1 and S2 angle between theta _2: its vertical plane around the cable forward path 10a If it is set like the angle formed by the magnetic field detecting elements S1 and S2,
The level ratio of the magnetic field detected by S2 is represented by the following equation, where R is R.

R = (V ₁₁ + V ₂₁ ) / (V ₁₂ + V ₂₂ ) ... (1) where V ₁₁ , V ₂₁ , V ₁₂ and V ₂₂ are the reciprocating routes 10a and 10b of the magnetic field generating cable 10 and the two magnetic fields described above. It is a value calculated by the combination with the detection elements S1 and S2. For example, assuming that the right displacement direction is the positive direction of x, the above parameters are And these parameters are used to calculate this V ₁₁ , V ₂₁ , V
₁₂ and V ₂₂ are expressed as follows.

By substituting the values of V ₁₁ , V ₂₁ , V ₁₂ , and V ₂₂ in these equations (3) to (6) into the above equation (1), the horizontal displacement amount x [m] and the corresponding level ratio R can be calculated. FIG. 6 is a graph showing the relationship. In the graph of FIG. 6, three types of underground depth such as D = 1 m, 2 m, and 3 m are assumed, and the level ratio R of the magnetic field detected by the magnetic field detecting elements S1 and S2 and the same magnetic field for each of these underground depths. Detector element S1
Center of round-trip cable of S and S2 (construction planning line PL) Vertical plane
It shows the relationship with the horizontal displacement from VP.

Now, according to the graph of FIG. 6, the two magnetic field detecting elements S1 and S2 under the above-mentioned conditions are located at the position of the vertical plane VP, that is, the horizontal displacement "0" with respect to the center of the reciprocating cable. For example, it can be seen that whatever the value of the depth D of the ground, the level ratio of each detected magnetic field is "1". Moreover, when the magnetic field detecting elements S1 and S2 are displaced in the right half direction from the position of the horizontal displacement amount "0", the same level ratio R becomes R> 1, and conversely, when they are displaced in the left half direction, Same level ratio R
R <1 and this exception does not occur. In addition, according to such a horizontal displacement measuring method, it is difficult to be influenced by the depth D in the ground.

In summary, the two magnetic field detection elements S1 and S2 are maintained at an angle of 45 degrees with respect to the vertical plane of the magnetic field generation cable 10 in which the magnetic field detection directions are orthogonal to each other and each of which reciprocates. When the level ratio of these detected magnetic fields is R = 1 when detecting the generated magnetic field, the magnetic field detection elements S1 and S2 are at the position of horizontal displacement "0" with respect to the center of the reciprocating path cable. If the level ratio R is R> 1, then the same magnetic field detection elements S1 and S2 are located at positions displaced in the right half direction with respect to the center of the reciprocating cable, and if the level ratio R is R <1, the same magnetic field is detected. It can be concluded that the detecting elements S1 and S2 are displaced in the left half direction with respect to the center of the round-trip cable. Further, the respective displacement amounts can also be obtained according to the value of the same level ratio R. These displacement amounts correspond to the same level ratio R, which is substantially independent of the depth D of the magnetic field detecting elements S1 and S2 themselves.

Here, the arrangement angle of the two magnetic field detection elements S1 and S2 with respect to the cable vertical plane is limited as described above, but basically, the magnetic field detection directions of the magnetic field detection elements S1 and S2 are the same as the cable vertical plane. As long as they are maintained at such angles that they are symmetric with respect to each other, it is possible to perform measurement in the horizontal displacement mode based on the same principle as described above.

FIGS. 1 to 4 show an embodiment of a horizontal displacement measuring device for an underground excavator according to the present invention, which is constructed based on such a principle. Refer to FIGS. 1 to 4 below. The configuration and operation of this embodiment will be described in detail.

FIG. 1 is a schematic cross-sectional view of a rough structure of the apparatus of this embodiment including an underground excavator that is in a working state, and FIG. 2 is a plan view of the apparatus of the same embodiment. FIG. 3 is a schematic diagram showing the cross-sectional structure of the main part of the apparatus of this embodiment viewed from the traveling direction of the underground excavator. In these figures, EP Is the ground surface, SH is the starting shaft, EH is the reaching shaft, 10 is the outward route 10a and the return route 10b along the construction planning line PL on the ground surface EP so that they are parallel to each other at equal intervals. A laid magnetic field generating cable, 20 is an underground excavator, 21 is a head of the excavator 20, 22 is a support arm that supports the head 21, 23 is a propulsion jack that propels the support arm 22, and S1 and S2 are For example, the above-mentioned magnetic field detection element composed of a coil, 24 is the magnetic field of these magnetic field detection elements S1 and S2. A posture support frame that supports the inside of the support arm 22 of the underground excavator 20 such that the outgoing direction always has the relationship shown in FIG. 5, 25 transmits the detection signals of the magnetic field detection elements S1 and S2. A traffic signal, 30 is provided on the ground as shown in the figure, supplies electric power to the cable 10 and, based on the detection signals of the magnetic field detection elements S1 and S2 transmitted through the signal line 25, the horizontal level of the underground excavator 20. The operation panels that collectively perform signal processing for displacement measurement are shown. The configuration of this operation panel 30 is the fourth
Details are shown in the figure.

That is, as shown in FIG. 4, the operation panel 30 also includes a display device 40 in which LEDs are arrayed in an array corresponding to the scale position indicating the horizontal displacement amount of the underground excavator 20 described above. And an oscillator 31 that oscillates an AC signal having an appropriate repetition frequency, and a power amplifier that power-amplifies the oscillated AC signal and supplies it to the magnetic field generation cable 10.
32, signal amplifiers 33a and 33b for amplifying the magnetic field detection signals of the magnetic field detection elements S1 and S2 transmitted through the signal line 25 with exceptionally the same gain, and removing noise components from these amplified signals. Bandpass filters (BPF) 34a and 34b that selectively filter only the effective signal component, shaping circuits 35a and 35b that shape the required waveform by rectifying or smoothing these filtered signals, and these waveform shaping 2
The magnetic field detection element described above by performing division using two signals
A divider 36 that outputs a value corresponding to the level ratio R of the magnetic field detected by S1 and S2, a reference level setter 37 that sets a desired comparison reference level in advance for the possible values of the level ratio R, and these set values. Comparison reference level and the above divider 36
Level comparator 38 that compares the output level of the above and outputs the result regarding its magnitude in correspondence with each set comparison reference level, and the LED of the display 40 based on the comparison output.
LED drive circuit that turns on and drives the corresponding LED in the array
Signal processing for measuring the horizontal displacement of the underground excavator 20 is executed in the following manner based on the above principle.

Now, assuming that an alternating current is supplied to the magnetic field generation cable 10 through the oscillator 31 and the power amplifier 32, for example, as shown in FIG. 5, the center of the forward route 10a and the backward route 10b of the cable 10, respectively. Generated concentric magnetic fields Ha and Hb. The magnetic field detecting elements S1 and S2 mounted in the underground excavator 20 in the manner shown in FIG. 5 are located in the right half direction or the left half direction with respect to the center of the round trip cable, that is, the vertical plane VP of the construction planned line PL. As described above, the level ratio R of the magnetic field detected by these elements S1 and S2 with respect to the generated magnetic field rises and falls with "1" as a boundary, depending on the existence of the magnetic field. This operation panel 30
Through the level comparator 38, the relationship between the level ratio R of the magnetic fields detected by the two magnetic field detecting elements S1 and S2 is R> 1 but R <1 and the horizontal displacement amount according to the degree. Along with the determination, the result is visually displayed on the display 40. As described in detail with reference to FIG. 6 above, in this case, for example, the reference level setting device 37
A voltage value corresponding to "1" and about "0.8" of the level ratio R of the detected magnetic field is preset, and the actual value of the level ratio R is between "0.8 and less than 1". At this time, the level comparator 38 determines that the measured level ratio R is within the preset reference level range based on the above-mentioned comparison of these values, and the corresponding L of the display 40 is passed through the LED drive circuit 39.
ED, that is, the LED indicating "0 to 20 cm to the left" is turned on. Thereby, the operator can know that the horizontal displacement amount of the underground excavator 20 is in the range of “0 to 20 cm to the left” with respect to the construction planning line PL. Similarly, the reference level setter 37 sets the level ratio R of the detection magnetic field to "1".
And the voltage value corresponding to about "1.3" is preset,
When the actual value of the same level ratio R is between "1 and less than 1.3", the same level comparator 38 determines that the same measurement level ratio R is the preset standard based on the same comparison of these values. It is determined that the level is within the level range, and the corresponding LED of the display 40, that is, the LED indicating "0 to 30 cm to the right" is turned on through the LED drive circuit 39. This allows the operator to know that the horizontal displacement amount of the underground excavator 20 is in the range of “0 to 30 cm to the right” with respect to the construction planning line PL. Generally, if it is desired to know the same horizontal displacement amount with n steps of resolution, the reference level setter 37 (n-1)
It suffices to prepare a reference level for comparison of species.

Thus, along with the excavation work by the underground excavator 20, the horizontal displacement mode (from the construction planning line PL) from the center of the reciprocating path cable of the excavator 20 and the displacement amount thereof are continuously measured, and the indicator is displayed. Through 40, the measurement contents are sequentially monitored in real time. Further, in this embodiment, since the horizontal displacement amount is obtained by the value of the level ratio of the magnetic fields detected by the two magnetic field detecting elements S1 and S2 as described above, the yawing and pitching of the underground excavator 20 can be performed. Accurate measurement that is not affected is realized.

In the above embodiment, the alternating current is supplied to the magnetic field generating cable 10, but the supplied current may be a direct current.

Further, the magnetic field generation cable 10 itself does not have to be a single wire, and may be a plurality of cables or a bundle of these plurality of cables.

Further, in the embodiment, the magnetic field detection directions (angles) of the two magnetic field detection elements are set according to the principle described based on FIGS. 5 and 6 above, but it is supplemented in the description of the principle. Basically, it suffices that the magnetic field detection directions of these elements are maintained at angles that are symmetrical to each other with respect to the vertical plane of the cable. So in these cases,
The value of the level ratio (R) of the detected magnetic field by these magnetic field detection elements for discriminating the left and right displacement modes described above may be changed according to the set angle.

Further, in this embodiment, an LED array as shown in FIG. 4 is used as the display 40, and the horizontal displacement amount of the underground excavator 20 with respect to the construction planned line PL is displayed in this lighting mode. However, such a display method is arbitrary, and in addition, for example, an analog level meter is used, and the horizontal direction of the underground excavator 20 is determined by the swing direction of the meter pointer around the level ratio R = 1 and the degree thereof. The displacement amount may be displayed, or only the displacement directions such as “right displacement” and “left displacement” may be displayed in binary.

Furthermore, in the same embodiment, the magnetic field detecting elements S1 and S2 are
The output of the above is directly transmitted to the signal amplifiers 33a and 33b in the operation panel 30, but in addition, an appropriate preamplifier is provided in the underground excavator 20, and these magnetic field detecting elements S1 up to a voltage level that is easy to transmit. The outputs of S2 and S2 may be pre-amplified. According to this, it becomes possible to achieve more stable operation of the measuring device.

Further, the circuit relating to the above-mentioned signal processing of the operation panel 30 may be replaced with a microcomputer and the same horizontal displacement amount may be obtained by the calculation at any time.

By the way, in the above description, it is premised that the horizontal displacement of the underground excavator is obtained based on the level ratio of the respective magnetic fields detected by the two magnetic field detection elements S1 and S2. Based on the comparison, necessary and sufficient information regarding the horizontal displacement mode can be obtained, and other methods such as taking a difference between the detected magnetic field levels can be sufficiently adopted.

In addition, it is possible to measure the displacement in the depth direction of the underground excavator with sufficient accuracy by using a well-known inclinometer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing the outline of the configuration of an embodiment of a horizontal displacement measuring device for an underground excavator according to the present invention, and FIG. 2 is a schematic plan view of the device of the same embodiment. FIG. 3 is a plan view showing a partial cross-sectional view of the apparatus of the same embodiment seen from the front side, FIG. 4 is a block diagram showing the configuration of an operation panel of the apparatus of the same embodiment, and FIG. 6 is a graph showing the relationship between the level ratio of the magnetic field detected by the two magnetic field detecting elements shown in FIG. 5 and the horizontal displacement amount from the center of the magnetic field. 10 …… magnetic field generation cable, 20 …… underground excavator, 21 …… head, 22 …… support arm, 23 …… propulsion jack, 24 ……
Posture support frame, 25 …… signal line, 30 …… control panel, 31 …… oscillator, 32 …… power amplifier, 33a, 33b …… signal amplifier, 34a, 3
4b …… Band pass filter, 35a, 35b …… Wave shaping circuit, 3
6 …… divider, 37 …… reference level setter, 38 …… level comparator, 39 …… LED drive circuit, 40 …… display, S1, S2 ……
Magnetic field detection element.

Claims (3)

[Claims] Claim: What is claimed is: 1. A magnetic field generation cable laid on the surface of the earth at a constant distance between the forward route and the backward route, a current supply means for supplying an appropriate current to the cable, and a magnetic field generation cable for the underground excavator. A first magnetic field detection element that is provided and fixedly supported so as to detect a magnetic field generated from the cable, the magnetic field detection direction being fixed and supported so as to be a direction inclined by a predetermined angle from the vertical direction when viewed from the front of the traveling direction of the excavator; The magnetic field detection direction is arranged in the underground excavator, and the magnetic field detection direction is a direction intersecting with the magnetic field detection direction of the first magnetic field detection element at an angle of line symmetry with respect to the vertical axis when viewed from the front of the traveling direction of the excavator. A second magnetic field detection element that is fixedly supported and detects a magnetic field generated from the cable, and the forward movement of the underground excavator based on a comparison of the detected magnetic field levels by the first and second magnetic field detection elements. A horizontal displacement measuring device for an underground excavator, comprising a determining means for measuring the horizontal displacement to the right and left of the center of the return path cable. 2. The underground excavator according to claim 1, wherein the predetermined angle formed by the first and second magnetic field detecting elements and the vertical direction when viewed from the front of the traveling direction of the excavator is 45 degrees. Horizontal displacement measuring device. 3. The method according to claim 2, wherein the determining means determines the horizontal displacement of the underground excavator based on the level ratio of the magnetic field levels detected by the first and second magnetic field detecting elements. A horizontal displacement measuring device for an underground excavator according to the paragraph.