JPH074179A - Pipe line survey method - Google Patents

Abstract

PURPOSE:To determine the two-dimensional and three-dimensional positions of a pipe line and the spatial position of an excavator for making a survey work efficient by connecting the outer casing of the excavator to one output end of an AC generator through an insulation coated cable, and then observing and measuring alternating field generated from the cable on the ground surface. CONSTITUTION:One conductive end of an insulation coated cable is electrically connected to the metallic outer casing of an excavator laid at the leading end of a pipe line, and then an AC generator covering a low audio frequency is installed near a shaft where the pipe line starts. One output end of the generator is connected to the conductive section of the cable and the other end is grounded at a position sufficiently away from the shaft, in order not to influence magnetic field near the pipe line and the excavator. Then, power is supplied to a circuit ranging from one output end of the generator to the other end via the casing of the excavator, thereby causing alternate current to flow in the cable in the pipe line. Thereafter, alternating field generated from the cable is observed and measured on the ground using a probe device, thereby first determining the position of the cable and the spatial position of the excavator. Then, a relative position between the cable and the pipe line is measured and the absolute position of the pipe line is determined on the basis of the cable as a reference position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an electromagnetic induction phenomenon to measure the three-dimensional position of an excavator and the spatial position of the entire pipeline from the ground when performing propulsion work or shield work. Regarding the method of surveying.

[0002]

2. Description of the Related Art Conventionally, in propulsion work or shield work, surveying of the entire pipeline and surveying the three-dimensional position of the leading excavator is generally done by optical surveying from inside the starting shaft using a transit or level. It was the target method. However, in optical surveying, depending on the performance of the surveying instrument, when surveying over 100 meters, it is often difficult to perform surveying due to the influence of water vapor, fog, and the like. Therefore, a method of irradiating a laser beam in a certain direction from the inside of the starting shaft to hit the target at the head position and knowing the head position from the target position irradiated with the laser spot is adopted. However, even with this method, there is a limit in distance, and there is a drawback that the spatial position of the head cannot be determined by one survey, especially when the road is invisible on a curved road.
In addition, since the survey is performed in the excavation work space, it is common to suspend the excavation work during the survey.

Therefore, recently, a method of attaching a low-frequency AC oscillator to the leading excavator, applying an alternating current to a minute coil, and observing and measuring the electromagnetic field generated from the coil on the ground surface to know the leading position is known. The method of utilizing the world has been adopted by some. However, the method using the electromagnetic field up to now measures the electromagnetic field generated from the minute coil considered as a dipole when viewed from the ground surface, so the strength of the electromagnetic field to be observed is not so large and it can be observed. A high-sensitivity measuring instrument is required for the measurement, and only by knowing the position of the leading excavator at all times, the survey of the entire pipeline must be performed by another method as needed.

[0004]

However, it has been difficult and difficult to obtain a strong magnetic field on the ground surface by the conventional magnetic field generating method using a minute coil, and only intermittent measurement of the head position has been possible. In view of these problems, it is an object of the present invention to provide a position surveying method for a leading machine of a pipeline or a segment tunnel and a surveying method capable of observing and measuring the entire location of the pipeline or the tunnel as needed from the ground surface.

[0005]

[Means for solving the problem] In order to solve such a problem, first, by observing an electromagnetic field generated when an insulating coated electric line which is installed in a propulsion pipe or a segment pipe is energized, the position of the entire pipeline is first confirmed in the electric line. Know by replacing it, then connect the tip of the electric line to the excavator outer cylinder, and observe this by utilizing the fact that the magnetic field changes rapidly at the outer cylinder position by grounding the outer cylinder to the ground. Therefore, the method of knowing the spatial position of the excavator was adopted.

[0006]

[Function] A sufficient electromagnetic field for observation and measurement can be easily obtained only by increasing the output of the generator or the oscillator.
Also, by observing from the ground surface, the work can be carried out independently of the excavation work. Since the electric line that generates the alternating electromagnetic field extends over the entire length of the pipeline, it can be used for surveying the entire pipeline. The alternating magnetic field generated from this electric line can be considered as an electromagnetic field due to a finite current, and the magnitude of the magnetic field in this case is shown as follows according to FIG.

[Equation 1]

The alternating magnetic field H generated by the electric current (alternating current) I flowing through the electric line AB is a magnetic field directed toward a concentric circle centered on the center of the cross section of the electric line, and its strength is expressed by the equation (1). , It decreases in inverse proportion to the distance from the electric line. Also, this magnetic field has no component in the direction of the electric line through which the current flows. From this fact, the alternating magnetic field has the following qualitative properties on the ground surface parallel to the electric line and the electric line. There is no vertical component just above the vertical line. It has no component in the direction of the electric line everywhere. Actually, the electric line is not always a perfect straight line, and the ground surface is not completely parallel to the electric line, but the error is generally negligible, so the position measurement of the electric line is
The horizontal position can be determined by using the above-mentioned qualitative property. Further, the depth at each point can be known from the ratio of the vertical component and the horizontal component of the alternating magnetic field at the two points deviating just above the electric line.

That is, from FIG. Then, the depth D is

[Formula 2] D × α = l ₁ (2)

Equation 3 Since the _{D × β = -l 2 ···················· (} 3), the addition of (2) and (3) l ₁ + l ₂ = D (α-β) = 1

[Equation 4] Here, α and β are respectively obtained as the ratio of the vertical component and the horizontal component of the magnetic field at that point, and l is obtained by the actual measurement between two points, so the depth D is determined. However, all of these must be handled on a plane perpendicular to the electric line.

Next, a general pipeline sectional view is shown in FIG. If the point B of the finite electric line AB is considered to be the grounding point of the excavator outer cylinder in the formula 4, β ₁ at this time becomes 0, and the formula 4 is

[Equation 5] Is written

[Equation 6] Becomes

Here, the ratio of the depth D of the excavator to the distance 1 of the electric line is

[Equation 7] Is between 0 and 1, but if we put it as X, x = 5 ... X = 0.986 x = 6 ... X = 0.9863 x = 8 ... X = 0.9923, which is 98 at x = 5, that is, at a distance of 5 times the depth.
% Similarity, x = 8, ie 99% similarity at 5 times the depth, can be considered as X = 1.
At that time,

[Equation 8] Becomes On the other hand, assuming that the distances to the points A and B at the point P _M that is approximately ½ of the pipeline extension are l ₃ and l ₄ , respectively, and if both are 5 times the depth or more, the equation (8) is

[Equation 9] Becomes That is, if the extension proceeds more than 10 times the depth, the strength of the magnetic field at the midpoint becomes twice the magnetic field at the position of the tip excavator.
Therefore, select P _M point under these conditions, to look for that intensity of the magnetic field is half of the PM point proceeds to the top direction that position is the position of the excavator.

[0011]

[Embodiment] One end of a current-carrying part of an insulated coated electric wire is electrically connected to a metallic outer cylinder of a machine for excavating a pipe, which is used for propulsion work or shield work. Place a sinusoidal alternating current of low frequency or higher frequency in the vicinity of the starting shaft of the pipeline, or an alternating current generator or oscillator containing high-order high-acoustic waves. The other end is grounded via a grounding plate or rod at a place sufficiently far from the starting shaft so as not to affect the magnetic field near the pipeline and the excavator. After that, from the output side end of the generator or oscillator, the insulated coating electric wire, the excavator outer cylinder, the ground, the ground plate or ground rod, through the wire to energize the circuit leading to the output side of the generator or oscillator, An alternating current is applied to the insulated wire in the pipe. First, the position of the insulating coated electric wire and the spatial position of the excavator are determined by observing and measuring the alternating magnetic field generated from the insulating coated electric wire thus installed from the ground by the exploration device. Next, the relative position of the insulated coated electric wire and the pipeline or segment is measured, and the absolute position of the pipeline or segment is determined based on the insulated coated electrical wire.

Next, a method of measuring the magnetic field will be described. Although the nature of the magnetic field generated from the pipe has been described in detail above, various implementation methods are actually possible in consideration of this nature. Therefore, an embodiment of the surveying method that is the easiest to understand will be described. First, as shown in FIG. 5, a method using probe coils assembled at right angles to each other will be described. The three coils are assembled so that their coil surfaces are perpendicular to each other. And each of them is x
Coils, y coils, and z coils. The coil may be circular or rectangular, but it is desirable that the area and the number of turns of the coil are the same. That is, if there is a difference in the area or the number of turns of the coil, it is necessary to correct the electromotive force of the same magnitude in the magnetic field of the same strength.

By applying an alternating current to the insulating coated electric line, the z coil of the three-element coil is always used horizontally on the ground surface. Measurement of horizontal position of electric line This three-element coil is placed on a substantially pipeline and moved left and right at a substantially right angle to the pipeline direction. If a point where the electromotive force of the Z coil is zero is obtained, it is placed vertically below that point. There is an electric line. In order to obtain the zero point of this electromotive force, a receiver may be connected to the Z coil and a silent point may be obtained by directly listening to an alternating current sound, or the electromotive force may be measured by a meter and displayed as a zero point. A method can be considered. In this way, zero points are successively obtained at points that are considered to be on the pipeline, and if these zero points are connected, it becomes the horizontal position of the electric line.

Next, at the Z coil zero point position, the X coil and the Y coil are rotated around the central vertical line of the Z coil while keeping the Z coil horizontal. Then, when the zero point of the Y coil is obtained, the direction of the frame of the Y coil at that time indicates the direction of the electric line at that point. Therefore, although the X coil may be located at any of the left and right positions, the ratio of the electromotive force between the X coil and the Z coil can be determined at any point moved in the direction of the frame of the X coil (that is, the direction perpendicular to the pipeline). Then, the ratio of the electromotive forces of the X coil and the Z coil is obtained at an arbitrary point on the opposite side. The method is most conveniently determined by the balance of the bridge circuit as shown in FIG. 6, and the balanced zero point detection at this time may be a method using a receiver sound or a meter. Next, if possible, move in the opposite direction and perform the same operation, and by obtaining α and β described above, the depth D can be obtained from the measured value l (distance between two points) and the fourth equation.

Next, a three-element coil is placed at approximately the center of the already-extended conduit extension and is installed so that the electromotive forces of the Y coil and the Z coil become zero. The other three-element coil is moved in the direction of the frame of the X coil while keeping the electromotive forces of the Y coil and the Z coil to be zero, and the electromotive force of the X coil is the X of the three-element coil previously installed. When the position of the magnetic field at which 50% of the electromotive force of the coil is obtained, that position becomes the horizontal position of the excavator. To determine this 50% position, and X coil using a sixth FIG bridge established the L _2,
It suffices to adjust r ₂ so that L ₁ is 50% of L _{2 in} calculation and then move the coil of L ₁ to obtain the equilibrium point.

[0016]

INDUSTRIAL APPLICABILITY The present invention can efficiently and accurately measure pipe line position measurement for shield construction, propulsion construction, and the like, and has the following advantages. The construction period can be shortened because the survey can be performed without interrupting the construction. Since surveying can be performed regardless of straight or curved roads, the surveying time can be shortened. It is possible to know the position of the excavator and the position of the pipeline at the same time. Survey equipment can be made at low cost.

[0017]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a magnetic field H received from a finite electric line AB at an arbitrary point.

FIG. 2 is an explanatory diagram showing how the alternating magnetic field spreads.

FIG. 3 is an explanatory view showing how to obtain the depth D of the electric line by two-point measurement.

[Fig. 4] Outline of pipe laying work (longitudinal section) and station position diagram

[Fig. 5] Bridge circuit diagram

FIG. 6 is a conceptual diagram showing how to combine the coils of the probe.

[Explanation of symbols]

I: Alternating current value r ₀ : Length of the perpendicular line drawn from the measurement point to the line segment AB ₁ : Angle at which the point B is seen from the measurement point β ₂ : Angle at which the point A is seen from the measurement point H: Magnetic field at the measurement point D: Depth from the ground surface to the electric line l: Distance between _two measuring points l ₁ · l ₂ : Distance from directly above the electric line to the measuring point Hv 1 · Hv 2: Vertical component of magnetic field Hh 1 · Hh 2: Horizontal component of magnetic field l _3: distance from the middle measuring point to shafts (oscillator output) l _4: intermediate distance from measuring point to the excavator (excavator contact) P: excavator (excavator contact) point directly above P _M: intermediate stations L ₁ : X-coil of a probe installed at an intermediate measuring point L ₂ : X-coil of a mobile probe R ₁ : resistance R ₂ : variable resistance, which is 1/2 of R ₁ .

Claims (1)

[Claims] 1. A metallic outer cylinder of a machine to be used for propulsion work or shield work and one end of an output of an alternating current oscillator or a generator are electrically connected by an insulation coated electric wire, and the output is provided. The other end of the cable is grounded at a place far enough from the influence of the magnetic field near the excavator, and the alternating magnetic field generated from the insulated wire is observed and measured on the ground surface by passing an electric current through the outer casing of the excavator. However, the pipe surveying method is characterized in that the three-dimensional position of the pipe or the shield segment and the spatial position of the leading machine are determined.