JP3224004B2 - Drilling tube tip location method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip position of a digging pipe when digging a straight line or a curve under an obstacle such as a river or a road and burying the pipe by a non-digging underground excavation method. It is about the method of exploring.

[0002]

2. Description of the Related Art Conventionally, in the case of digging underground and buried piping by a non-digging underground excavation method such as a small-diameter propulsion method, a method of simultaneously exploring the horizontal and vertical deviation of the tip position of the excavation pipe is known. And JP-A-62-266484.

In this method, as shown in FIGS. 9 and 10, a magnetic sensor 3 is moved down to a plurality of vertical boring holes a, b, c excavated on a line crossing a target excavation orbit 1 to detect magnetism. This is a method of exploring the horizontal position and the vertical position of the tip of the excavation pipe by excavating the plurality of boring holes a, b, and c before the propulsion work, and inserting the non-magnetic pipe 5 into the boring holes. After the propulsion work, it is necessary to remove the non-magnetic pipe 5 from the boring hole and backfill the boring hole, which requires labor and time. In addition, since it is not easy to increase the number of search holes, there is a problem that it is difficult to provide a search point at an arbitrary position during propulsion.

[0004] In addition, Japanese Unexamined Patent Publication No. Sho 63 (1988) discloses a method in which a magnetic field is generated from the surface of the ground to the ground without providing such a boring hole, and the magnetic strength is detected at the tip of the excavator to locate the position. No. 307301.

Japanese Unexamined Patent Publication (Kokai) No. 63-307301 describes that, as shown in FIGS. 11 (a) and 11 (b), a pair of conductors 7 arranged in parallel along a target orbit line 1 An electric current is supplied to generate an alternating magnetic field in the ground, and the two magnetic field detectors 20 are provided on the left and right of the outer peripheral wall of the underground excavation pipe 6.
The horizontal position deviation δ is calculated by a predetermined arithmetic processing.

Further, as an exploration method capable of grasping a vertical displacement, there is a method disclosed in Japanese Patent Publication No. 7-35970. This is one in which the magnetic field detectors 20 are arranged above and below the outer peripheral wall of the tunnel 6 in the same magnetic field detection method as described above.

[0007]

The exploration of the excavation pipe tip position by the magnetic field detecting means cannot detect the horizontal displacement and the depth detection at the same time. In addition, there is a problem that if a magnetic object exists in the ground or around the surface of the ground to be excavated, the magnetic field is affected and the search accuracy is reduced. SUMMARY OF THE INVENTION It is an object of the present invention to provide a means for simultaneously and accurately exploring the horizontal displacement and depth of the tip of an underground tunnel using a magnetic sensor.

[0008]

In order to simultaneously detect the horizontal displacement and the depth of the tip of an underground excavation pipe,
For example, it is conceivable to solve the above problem by providing the magnetic field detectors of the above-mentioned prior arts of JP-A-63-307301 and JP-B-7-35970 at the right and left and up and down of the excavation pipe, that is, at four places to detect the magnetic field strength. However, the present invention uses a different means.

That is, in the prior art, a magnetic field detector ignoring the detection directionality is disposed at predetermined positions on the left, right, upper and lower sides of the outer periphery of a digging tube, and the position is calculated by detecting the distribution of the magnetic field intensity. In the case of the present invention, the magnetic sensors having the detection directionality are made orthogonal at the same position, and the magnetic field components in three axial directions of front and rear (X), left and right (Y), and vertical (Z) are measured and separately obtained. The horizontal position and the depth of the tip of the excavation tube are simultaneously searched from the relationship with the posture of the excavation tube (inclination θi, azimuth θd, and rotation angle θt).

As a means for performing an accurate search, a magnetic field intensity due to the earth's magnetic field at a search point is measured in advance, and this is subtracted from the magnetic field strength at the time of the search, thereby obtaining a magnetically-occurring object existing in the vicinity. High accuracy is achieved by eliminating the effect of the generated magnetic field.

[0011] The method of searching for the tip position of a drilling pipe according to the present invention is suitable for propelling a drilling pipe by an underground excavation method.
Then , a loop-shaped magnetic field generating coil is arranged at an arbitrary exploration point on the target excavation trajectory between the starting section and the arrival section, and the three-axis magnetic fields orthogonal to each other are arranged in the nonmagnetic collar at the tip of the underground excavation pipe. A sensor is provided, and an attitude measuring sensor for detecting the inclination, rotation angle and direction of the excavation pipe is provided in the vicinity of the magnetic sensor. First, without energizing the coil, the magnetic field intensity (Hax, Hay, HaZ) is detected,
Next, the magnetic field in the ground is changed while direct current or rectangular alternating current is applied to the coil, and the magnetic field intensity (Hix, Hiy, HiZ) in three axial directions is detected by the magnetic sensor. The azimuth θd and the rotation angle θt are measured by a posture measurement sensor, and the three-axis magnetic field strength obtained by subtracting the corresponding axial magnetic field strength in a non-energized state from the three-axis magnetic field strength in a state where the coil is energized. A predetermined calculation is performed from the values of the inclination θi, the azimuth θd, and the rotation angle θt of the excavation pipe, and the horizontal position and the depth of the tip of the excavation pipe are simultaneously obtained.

[0012]

Next, the present invention will be described in detail with reference to the illustrated examples. When the present invention is carried out and the position of the tip of the excavation pipe is searched in the underground excavation method, as shown in FIG. 1, the starting portion of the excavation pipe propelled by the excavation pipe propulsion device 4 fixed on the ground and reaches Target propulsion trajectory 1
A rectangular magnetic field generating coil 7 is installed at an arbitrary search point on the ground surface 2 above, and a power supply 8a for supplying a current to the coil 7 is further provided. Keep it. A current detector 8b is provided between the coil 7 and the power supply 8a. The shape of the magnetic field generating coil 7 can be set three-dimensionally as long as its shape can be grasped, and may be installed not only on the ground surface 2 but also in the ground or in the air.

At the starting side, the number of propulsion of the excavation tube 6 is counted and the excavation propulsion is performed while grasping the propulsion distance, and the magnetic detection sensor disposed in the non-magnetic collar 10 at the rear end of the excavation tube at the tip is used. A measuring device 11 capable of detecting the inclination, rotation angle and direction is included immediately below a predetermined magnetic field generating coil 7.
Alternatively, when the vehicle reaches the vicinity, the propulsion work is temporarily stopped there.

At this time, the coil is not energized, and the magnetic field is first detected by the magnetic detection sensor by the magnetic field in the three-axis (X, Y, Z-axis) directions 14 including the direction of the excavation axis as shown in FIG. component H _ax, H _ay, detecting the H _aZ. At the same time, the inclination angle θi15 of the magnetic detection sensor unit in the central axis direction as shown in FIGS. 3 to 5, the azimuth angle θd16 with respect to the target propulsion trajectory 1, and the rotation angle θt17 from the initial state about the excavation axis. Is detected by the measuring device 11 arranged on the non-magnetic collar 10. At this time, each detected value is displayed on the ground attitude display system 13 (see FIG. 1).

Subsequently, with the excavation tube 6 stopped at the same position, a constant current I is supplied to the magnetic field generating coil 7 by the power supply 8a to change the magnetic field near the excavation tube tip. The components H of the magnetic field strength in three axial directions including the direction of the excavation axis by the magnetic detection sensor and orthogonal to each other
_ix, H _iy, to detect the H _iZ. The above is the operation procedure for obtaining the data required for obtaining the excavation pipe tip position in the present invention.

The procedure and method for obtaining the excavation pipe tip position using the above data will be described below.

First, by subtracting each component of the magnetic field strength due to the terrestrial magnetic field from each component of the magnetic field strength when the current I is supplied to the coil 7, that is, from the following equation (1), the artificially generated magnetic field is obtained. The intensity components H1, H2, H3 are calculated. _{H1 = H ix - H ax H2} = H iy - H ay (1) H3 = H iZ - H aZ

Subsequently, the above detected values θi15, θd1
6, and based on a specific conversion equation using θt17,
(1) each coordinate axis as shown in FIG. 2 the components H1, H2, H3 of the magnetic field strength determined by formula (X ', Y', Z ' axis) components H _X of the magnetic field intensity with respect to the direction 18', H _Y ', _HZ '
Convert to Here, the reference embodiment is based on the coordinate axes (X ′,
(Y ', Z' axes), the X 'axis is parallel to the azimuth of the target propulsion trajectory 1, and the X', Y 'axes are parallel to the horizontal plane, but the position of the reference point O does not matter.

On the other hand, the components H _Xt, H _{Yt, and} H _Zt of the theoretical value of the magnetic field intensity in each coordinate axis (X ′, Y ′, Z ′ axis) direction at an arbitrary position with respect to the reference point O are represented by coils 7. Can be calculated in advance from the shape, scale, and supply current value I of. For example, the position of the magnetic detection sensor is determined by (X _o , Y _o ,
Z _o) Assuming that H _Xt, H _Yt, H _Zt in accordance with the law of Biot-Savart is the basis principles of the relationship between magnetic field formed current and its surroundings, as described below X _o,
It is shown as a function of Y _o , Z _o , and current I. H _Xt = f ₁ (X _o , Y _o , Z _o , I) H _Yt = f ₂ (X _o , Y _o , Z _o , I) H _Zt = f ₃ (X _o , Y _o , Z _o , I )

Since the position where these calculated magnetic field strengths are equal to the above-described detected magnetic field strength components H _X ′, H _Y ′, H _Z ′ is the position of the magnetic detection sensor, the following simultaneous equation (2)
And solve the coordinates ( _Xo , _Yo ,
The position can be known by determining Z _o ). _{H X '= H Xt = f} 1 (X o, Y o, Z o, I) H Y' = H Yt = f 2 (X o, Y o, Z o, I) (2) H Z '= H _{Zt = f 3 (X o,} Y o, Z o, I)

As one of the general methods for solving the above equation (2), there is a method in which an approximate value of the solution is set first, and convergence calculation is performed by the Newton-Raphson method to calculate the solution. Therefore, when the present calculation method is applied on site, the calculation can be performed using a computer in which software in which the above-described numerical calculation method is programmed in advance is installed in order to obtain an analysis result instantaneously.

As the supply current I, a DC current may be supplied. However, a rectangular alternating current as shown in FIG. 6 is used. By increasing the number of times, it is also possible to efficiently suppress errors during measurement.

In addition, if the installation range of the coil is increased,
The measurable depth can be increased by increasing the supply current value I. As means for increasing the supply current value I, it is effective not only to increase the supply voltage, but also to use the coils 7 stacked in several stages as shown in FIGS. In the embodiment of the present invention, a direct current of about 8 amperes is supplied to a rectangular coil having a side length of 20 m × 17 m and a 60-turn cable, and a dug tube having a depth of about 20 m from the ground surface is provided. The position of the tip was detected. At that time, the respective measurement results regarding the magnetic field strength and the attitude of the tip were as follows. _{H1 = H ix - H ax =} -0.05 H2 = H iy - H ay = 0.00 H3 = H iZ - H aZ = -0.24 ( units gauss)

Θi = + 13 degrees (the tip is upward +) θd = + 2 degrees (the right direction is + toward the excavation direction) θt = −22 degrees (the clockwise direction is ++ toward the excavation direction) The result of calculating the excavation pipe tip position using various data is shown below. Here, X ', Y', and Z 'represent coordinates with respect to the origin O shown in the figure. X ′ = − 3.64 m (position with respect to the excavation direction axis) Y ′ = + 0.68 m (horizontal displacement) Z ′ = + 21.16 m (vertical downward depth)

[0025]

As described above, by applying the present invention to a straight excavation method or a non-cutting propulsion construction method in which a vertical curve is excavated, the horizontal position and the depth of the excavation pipe tip can be accurately and quickly determined. This makes it possible to grasp the deviation of the laid pipe position from the planned route by a simple method.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment in which the present invention is applied to uncutting excavation work.

FIG. 2 is an explanatory perspective view showing a positional relationship between a coordinate system used for calculation of the present invention and a measuring instrument.

FIG. 3 is an explanatory diagram showing detection values of a measuring instrument used in the present invention.

FIG. 4 is an enlarged view as viewed from an arrow A in FIG. 3;

FIG. 5 is a view taken in the direction of arrows BB in FIG. 3;

FIG. 6 is a diagram showing a rectangular alternating current used as a means of the present invention.

FIG. 7 is a diagram of an embodiment of the present invention in which detection is performed by superposing magnetic field generating coils.

8 is a view as viewed in the direction of the arrow C in FIG. 7;

FIG. 9 is a perspective view of a first conventional example.

FIG. 10 is an enlarged explanatory view of a portion D in FIG. 9;

FIG. 11 is an explanatory view of two cross sections at different angles in the second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Target propulsion track 2 Ground surface 4 Drilling tube propulsion device 7 Magnetic field generating coil 8a Power supply device 8b Current detector 9 Connection cable 10 Non-magnetic color 11 Measuring device 12 Transmission cable 13 Attitude display system 15 Angle of inclination of magnetic detection sensor 16 Magnet Azimuth angle of detection sensor 17 Rotation angle of magnetic detection sensor

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-260284 (JP, A) JP-A-4-293895 (JP, A) JP-A-56-145304 (JP, A) JP-A-62 106313 (JP, A) JP-B-63-41491 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 9/06 301 E21D 9/06 311 G01B 7/00 G01C 15 / 00 104

Claims (1)

(57) [Claims] (1) Drilling pipe is propelled by non-drilling underground excavation method
At this time, a loop-shaped magnetic field generating coil is arranged at an arbitrary search point on the target excavation trajectory between the starting part and the arrival part, and the three-axis directions orthogonal to each other are arranged in the nonmagnetic collar at the tip of the underground excavation pipe. A magnetic sensor is provided, and a posture measuring sensor for detecting the inclination, rotation angle, and direction of the excavation pipe is provided in the vicinity of the magnetic sensor. First, without energizing the coil, the magnetic sensor measures the magnetic field strength in three axial directions (Hax, Hay). , HaZ), then change the underground magnetic field in a state where a DC or rectangular alternating current is applied to the coil.
The magnetic field strength in the axial direction (Hix, Hiy, HiZ) is detected, and the inclination θi, the azimuth θd, and the rotation angle θt of the excavated pipe are separately measured by a posture measuring sensor, and the magnetic field in the three axial directions in a state where the coil is energized. Magnetic field strength in three axial directions obtained by subtracting the magnetic field strength in the corresponding axial direction in a state where no current is supplied from the strength,
A method for searching for a position of a tip of a digging pipe, wherein a predetermined calculation is performed from values of the inclination θi, the azimuth θd, and the rotation angle θt of the digging pipe, and a horizontal position and a depth of the tip of the digging pipe are simultaneously obtained.