JP2551805B2 - Horizontal displacement measuring device for underground excavator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a horizontal displacement measuring device for an underground excavator for burying a water pipe, a gas pipe or the like in the ground by a propulsion method.

(Prior Art) Conventionally, a propulsion method has been used as a method for accurately burying a small-diameter pipe such as a water pipe or a gas pipe in the ground along a planned line.

The above-mentioned propulsion method first propels the front conduit from the starting vertical shaft toward the reaching vertical shaft to propel the front conduit, and then guides this front conduit to dig a small-diameter pipe into the ground,
The small-diameter pipe is designed to be buried accurately along the planned line, and the burying accuracy of the small-diameter pipe is determined by the burying accuracy of the leading pipe.

For this reason, various measuring methods have already been proposed in order to bury the leading conduit with high accuracy in the ground.

The present applicant has previously filed Japanese Patent Application No. 61-10700 (Japanese Patent Laid-Open No. 62-169).
No. 012) was proposed.

This is a magnetic field cable is laid on the ground surface so that the forward line and the double line are located at equal intervals along the planned line where the underground excavator (leading device) is promoted, and the magnetic field is detected on the underground excavator side. The horizontal displacement of the underground excavator is continuously measured in real time by installing a device and detecting the magnetic field generated by the magnetic field generation cable with this magnetic field detector. There is an effect that it can be installed without blocking the traffic even when it is buried in the.

Further, JP-A-62-25202 proposed by the present applicant (JP-A-6-25202)
(2-169012) also measures the underground position of an underground excavator by laying a reciprocating line of a magnetic field generation cable on the surface of the ground to generate a magnetic field and receiving the magnetic field with a magnetic field detection element in the underground excavator. In doing so, the construction plan line of the underground excavator on the surface of the ground is sandwiched, and the reciprocating line of the magnetic field generating cable is laid on both sides of the construction plan line with a distance according to the construction plan depth of the underground excavator. Is.

(Problems to be solved by the invention) However, in the above-mentioned conventional horizontal displacement measuring device, as shown in FIG. 11, the value of the indicator for displaying the displacement amount with respect to the actual displacement amount depending on the burial depth of the small diameter pipe. Variation occurs, and the sensitivity of the display decreases as the burial depth deepens, and the measurement accuracy is affected by the burial depth.
There was a problem that the deeper the burial depth, the more difficult the burial could be.

The present invention has been made for the purpose of improving the above-mentioned inconvenience, and by adding a depth calibration circuit newly, a horizontal displacement measuring device for an underground excavator that eliminates the displacement of the display due to the depth even if the buried depth changes. It is the one we are trying to provide.

(Means and Actions for Solving the Problem) In order to achieve the above-mentioned object, a magnetic field generated from a magnetic field cable laid in advance on the surface of the earth along the construction planning line,
It is detected by a pair of magnetic field detection elements installed in the underground excavator that propels the ground, and the horizontal displacement of the underground excavator is calculated from the magnetic field level detected by the magnetic field detection element and displayed on the display. In the horizontal displacement measuring device of the underground excavator, the magnetic field cable is laid at a constant round-trip line interval regardless of the depth of the underground excavation, and the horizontal displacement is calculated from the magnetic field level detected by the magnetic field detection element. In the circuit, the variable resistor of the depth calibrator is rotated according to the depth, and the depth calibration means for setting the desired depth is provided, so that the value displayed on the display varies depending on the depth of the small diameter pipe to be buried. A horizontal displacement measuring device for an underground excavator is provided that prevents small diameter pipes such as water pipes and gas pipes from being buried accurately along the construction plan line without being affected by the burial depth. It is Utosuru thing.

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

Now, as shown in FIG. 5, assuming that a magnetic field generating cable 10 composed of a forward route 10a and a multiple route 10b, which are separated from each other by a predetermined distance, is laid on the ground surface EP, and a proper current is applied to this, Magnetic fields Ha and Hb are generated concentrically around the round trip lines 10a and 10b of the cable 10 in the manner shown in FIG.

In the present invention, the magnetic fields Ha and Hb thus generated are simultaneously detected by the two magnetic field detection elements S1 and S2 as shown in FIG.

For the sake of simplicity, it is assumed here that the two magnetic field detecting elements S1 and S2 have their magnetic field detecting directions orthogonal to each other, and each of them is maintained at an angle of 45 degrees with respect to the vertical plane of the cable 10.

Under these conditions, each parameter is set as shown in FIG. 5, that is, L: distance between 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. Magnetic field prefectural element S1 and S2
Distance to: 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 of the elements S1 and S2 from the cable outward route 10b θ ₁ : Vertical angle about the cable double route 10b and the angle between the magnetic field detecting elements S1 and S2 θ ₂ : Vertical plane around the cable double route 10a And the magnetic field detecting elements S1 and S2 make an angle, the above two magnetic field detecting elements S1 and S2
The level ratio of the magnetic field detected by is expressed by the following equation where R is this.

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 above two magnetic fields. Sensing elements S1 and S2
It is a value calculated by the combination with.

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.

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 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 depths. The relationship between the center of the round trip cable of the detection elements S1 and S2 (construction planning line PL) and the horizontal displacement from the vertical plane VP is shown.

According to the graph of FIG. 6, the two magnetic field detecting elements S1 and S2 placed under the above-mentioned conditions are located at the position of the vertical plane VP, that is, the horizontal displacement amount "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 from the position of the horizontal displacement amount “0” in the right half direction, the same level ratio R becomes R> 1, and conversely, when they are displaced in the left half direction, the same level ratio R is obtained. Level ratio R
R becomes less than 1 and this exception does not occur. Also, according to such horizontal displacement measurement method,
It is also unlikely to be affected by the above-mentioned depth D.

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 R of these detected magnetic fields is 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 cable, and the level ratio R Is R> 1, the magnetic field detecting elements S1 and S2 are located at positions displaced in the right half direction with respect to the center of the reciprocating cable, and when the level ratio R is R <1, the magnetic field detecting element S1 is And S2 is concluded to be displaced in the left half direction with respect to the center of the round-trip cable.

Further, it is possible to also obtain the respective variation amounts 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 angles such that they are symmetrical with respect to each other, the measurement regarding the horizontal displacement mode can be performed 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. Hereinafter, FIGS. 1 to 4 will be described below.
The configuration and operation of the embodiment will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a rough structure of the embodying apparatus including an underground excavator in a working state, and FIG. 2 is a schematic plan view of the embodying apparatus of the same embodiment. FIG. 3 is a schematic cross-sectional view of the main part of the apparatus of this embodiment as seen from the traveling direction of the underground excavator. In these figures, EP is a ground surface map. , SH
Is a starting shaft, EH is a reaching shaft, and 10 is a magnetic field generating cable laid along the construction planning line PL on the ground surface EP so that the outgoing lines 10a and a plurality of lines 10b are parallel to each other at equal intervals. , 20 is an underground excavator, 21 is a head of the excavator 20, 22
Is a support arm that supports the head 21, and 23 is the support arm
Propulsion jacks for propelling 22, S1 and S2 are the above-mentioned magnetic field detecting elements composed of, for example, a coil, and 24 is such that the magnetic field detecting directions of these magnetic field detecting elements S1 and S2 are always in the relationship shown in FIG. Attitude support frame supported in the support arm 22 of the underground excavator 20, 25 is a child signal device for transmitting the detection signals of the magnetic field detection elements S1 and S2, and 30 is provided on the ground as shown to provide the magnetic field generation cable 10 To the magnetic field detection element S1 transmitted through the signal line 25 while supplying power to
And an operation panel that collectively executes signal processing for horizontal displacement measurement of the underground excavator 20 based on the detection signals of S2.

 The structure of the operation panel 30 is shown in detail in FIG.

That is, as shown in FIG. 4, the operation panel 30 also includes a display unit 40 in which LEDs are arranged in an array correspondingly to the scale position indicating the horizontal displacement amount of the underground excavator 20 described above. An oscillator 31 that oscillates an alternating current signal having a proper repetition frequency and a power amplifier that amplifies the oscillated alternating current signal and supplies it to the magnetic field generation cable 10.
32 has a transmitter A, the output of which is the seventh
As shown in the figure, a transmission cable 45 supplies the magnetic field generating cable 10 laid on the surface of the earth.

In addition, the magnetic field detection element S1 provided in the underground excavator 20 and
The magnetic field detection signal of S2 is the underground excavator 20 as shown in FIG.
Is transmitted to the arithmetic processing circuit B provided in the operation panel 30 via the signal line 25 connecting the control panel 30 and the operation panel 30, and the arithmetic processing circuit B amplifies the magnetic field detection signal with the same gain. Signal amplifiers 33a and 33b, bandpass filters (BPF) 34a and 34b that remove noise components from these amplified signals and selectively filter only effective signal components, and rectify and smooth these filtered signals. The shaping circuits 35a and 35b for shaping the waveform as required by, for example, performing the division using the two waveform-shaped signals to perform the above-mentioned magnetic field detection element S1.
And a divider 36 that outputs a value corresponding to the level ratio R of the magnetic field detected by S2, a depth calibrator 46 that calibrates a slight variation in detection caused by the burial depth, and a desired visual reference for the possible value of the level ratio R. The reference level setter 37 for setting the level, compares the set comparison reference level with the output level of the divider 36, and the result regarding the magnitude is compared with the set comparison reference level. Output to the level comparator 38, and drives the corresponding LED in the LED array of the display 40 based on the comparison output.
Each has an LED drive circuit 39, and these specific circuits are shown in FIG.

The depth calibrator 46 newly added in the above circuit is equipped with a variable resistor VR10 that is variable according to the buried depth. The horizontal displacement amount calculated by the arithmetic processing circuit B is calibrated by the depth D to obtain the depth. The horizontal displacement can be measured without being affected by the depth even if is changed.

Next, measurement of horizontal displacement of the underground excavator 20 will be described.

Now, assuming that an alternating current is supplied to the magnetic field generating cable 10 through the oscillator 31 and the power amplifier 32, for example, the forward route 10a and the backward route 10b of the cable 10 as shown in FIG. Concentric magnetic field Ha and
Hb is generated.

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 the elements S1 and S2 with respect to the generated magnetic field rises and falls at the boundary of "1", depending on the existence of the magnetic field.

The operation panel 30 includes two magnetic field detecting elements S1 and
Whether the level ratio R of the magnetic field detected by S2 is R> 1 or R <1
The level comparator 38 determines the horizontal displacement amount according to the relationship and the degree, and the result is visually displayed on the display 40.

As will be described in detail with reference to FIG. 6 above, at this time, for example, the reference level setter 37 is preset with a voltage value corresponding to “1” and about “0.8” of the level ratio R of the detected magnetic field. When the actual value of the same level ratio R is between "0.8 and less than 1", the level comparator 38 determines that the measured level ratio R is equal to or less than the above based on the above-mentioned comparison of these values. It is judged that it is within the set reference level range, and the corresponding LED of the display 40, that is, "0 to 20c to the left, is displayed through the LED drive circuit 39.
Turn on the LED indicating "m".

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 is preset with voltage values corresponding to "1" and about "1.3" of the level ratio R of the same detection magnetic field, and the actual value of the same level ratio R is " 1-1.
If it is between "less than 3", the same level comparator 38
Based on the same comparison of these values as above, the same measurement level ratio R
Is determined to be within the preset reference level range, and the corresponding LED of the display 40, that is, the LED indicating "0 to 30c to the right" is turned on through the LED drive circuit 39.

Thereby, the operator can know that the horizontal displacement amount of the underground excavator 20 is in the range of “3 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, it is sufficient to prepare (n-1) kinds of comparison reference levels in the reference level setter 37.

Thus, along with the excavation work by the underground excavator 20, the horizontal displacement mode (from the construction planning line PL) and the displacement amount thereof from the center of the reciprocating path cable of the excavator 20 are continuously measured, and the display 40 Through this, the measurement contents are sequentially monitored in real time.

The above is the case where the burial depth of the small diameter is as deep as 1.5 m, but when the burial depth becomes deep, the magnetic field reaching the magnetic field detection elements S1 and S2 becomes weak and the detection accuracy deteriorates.

When the burial depth changes, the variable resistor VP10 of the depth calibrator 46 is rotated according to the depth D to set the desired depth.

Thus, the theoretical formula for obtaining the horizontal displacement amount x is as follows.

If l ² + D ² >> x ² and the x ² term is ignored, Solving for the x term If l ² << D ² Note that R: reception level of the magnetic field detection element V ₁ : output of the magnetic field detection element S1 V ₂ : output of the magnetic field detection element S2 D: depth l: cable installation planning line distance The arithmetic processing circuit B is based on the above theoretical formula. Since the result of the arithmetic processing is output to the display 40, the value displayed on the display 40 does not vary in characteristics even if the burial depth changes as shown in FIG. It becomes possible to correct the direction of the underground excavator 20 without being affected.

In the above embodiment, the alternating current is supplied to the magnetic field generating cable 10, but the supplied current may be 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 this embodiment, the magnetic field detection directions (angles) of the two magnetic field detection elements were determined according to the principle described with reference to FIGS. 5 and 6 above. 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.

That is, in such a case, the value of the level ratio (R) of the magnetic field detected by these magnetic field detecting 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 twisting direction of the meter pointer around the level ratio R = 1 and its degree. 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 outputs of the magnetic field detecting elements S1 and S2 are directly transmitted to the signal amplifiers 33a and 33b in the operation panel 30, but the magnetic field detecting elements S1 and S2 of the magnetic field detecting elements S1 and S2 can be easily transmitted. The output 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 assumed that the horizontal displacement of the underground excavator is obtained based on the level ratio of the detected magnetic fields by the two magnetic field detection elements S1 and S2. On the basis of such comparison, necessary and sufficient information regarding the horizontal displacement mode can be obtained, and other methods such as taking the difference between the detected magnetic field levels can also 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.

(Effect of the Invention) As described in detail above, according to the present invention, the arithmetic processing circuit is provided with the depth calibrator, and the arithmetic value is calibrated according to the buried depth. Since there is no variation depending on the burial depth as in the past, there is no risk of incorrect direction correction.

This makes it possible to bury a small-diameter pipe with high accuracy along the construction plan line, without increasing the error even if the burial depth becomes deep, and burying in a narrow urban area. By providing it, the distance between the reciprocating lines of the magnetic field generating cable is constant, and the horizontal displacement can be accurately measured.

Further, in the measurement of the position of the magnetic field generation cable laid on both sides of the construction planning line, the distance between the round trip lines of the magnetic field generation cable is not related to the burial depth, so the number of measurement points can be small and the magnetic field generation cable can be laid efficiently.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing the outline of the calibration of an embodiment of a horizontal displacement measuring apparatus for an underground excavator according to the present invention, and FIG. 2 is a plan view of the apparatus 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. FIG. 6 is a graph showing the relationship between the magnetic field level ratio detected by the two magnetic field detecting elements shown in FIG. 5 and the horizontal displacement amount from the magnetic field center, and FIG. 7 is a circuit of the transmission system. Fig. 8 is a circuit diagram of a receiving system, Fig. 9 is a circuit diagram of an arithmetic processing circuit, Fig. 10 is a diagram showing a display after calibration with respect to an actual horizontal displacement amount, and Fig. 11 is an actual circuit by a conventional device. It is a diagram showing the relationship between the horizontal displacement amount and the display value. 10 …… Magnetic field generating cable, 20 …… Underground excavator 40 …… Display, 46 …… Depth calibration circuit B …… Computation processing circuit, S1 …… Magnetic field detecting element S2 …… Magnetic field detecting element

Claims (1)

(57) [Claims] 1. A pair of magnetic field detection elements installed in an underground excavator (20) for propelling the magnetic field generated by a magnetic field cable (10) laid on the ground surface along a planned construction line in advance. The horizontal displacement of the underground excavator (20) is calculated by the magnetic field levels detected by the magnetic field detecting elements (S1) and (S2) while being detected by (S1) and (S1), and then displayed on the display (40). In the horizontal displacement measuring device of the underground excavator configured to display, the magnetic field cable is laid at a constant reciprocating route interval regardless of the depth of the underground excavator, and the magnetic field detecting element (S1),
The variable resistor (VR10) of the depth calibrator (46) is rotated according to the depth (D) of the arithmetic processing circuit (B) that calculates the horizontal displacement from the magnetic field level detected by (S2), and the desired depth is set. A horizontal displacement measuring device for an underground excavator, characterized by being provided with a depth calibrating means.