JPS6218690B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an underground excavation device suitable for use in excavating underground continuous walls, site pouring, open caisson excavation, ground modification, and the like.

(b) Technology background Recently, the shape of a borehole drilled by an underground drilling rig can be displayed instantly on a display by online processing of ultrasonic waves reflected from the excavation wall, allowing for accurate construction in a short time. There have been proposals to do so.

However, with these methods, the problem is how to accurately calculate and measure the distance from the reflected ultrasonic waves, and there has been a desire to develop underground drilling equipment that can process such data.

(c) Purpose of the Invention In view of the above circumstances, an object of the present invention is to provide an underground excavation device that can easily and accurately perform calculation and measurement of accurate distance using ultrasonic waves.

(d) Structure of the Invention That is, the present invention provides one or more corrective ultrasonic wave transmitting/receiving means on the rod near the excavation part, and furthermore, at least two reflecting members are provided so as to be able to protrude and retreat from the rod. , and are arranged such that the distances from the correcting ultrasonic wave transmitting/receiving means are different from each other.

(e) Embodiments of the invention Hereinafter, embodiments of the invention will be described based on the drawings.

FIG. 1 is a front view showing an embodiment of the underground excavation apparatus according to the present invention, FIG. 2 is a partial sectional view of the vicinity of the excavation part of the underground excavation apparatus shown in FIG. 1, and FIG. 3 is a front view of the underground excavation apparatus shown in FIG. FIG. 4 is a plan view showing the method of distance measurement of an excavated hole using ultrasonic waves, and FIGS. 5 and 6 are time charts showing the method of correction using ultrasonic waves for correction.

As shown in FIG. 1, the underground excavation equipment 1 has a pedestal 2, and a disc-shaped rotary table 3 is rotatably supported on the pedestal 2. A bevel gear 3a is formed on the upper side of the rotary table 3, and a bevel gear 5a provided at the tip of a shaft 5 rotatably supported by the pedestal 2 meshes with the bevel gear 3a. A spur gear 5 is attached to the other end of the shaft 5.
b and a rotation angle meter 6 are provided, and a spur gear 5
b is a spur gear 7a attached to the output shaft of the motor 7;
are meshing. A hole 3b with a square cross section is formed through the center of the rotary table 3, and a hollow rod 9 with a square cross section is rotatably suspended from the upper end (not shown) by a crane or the like in the hole 3b. They are fitted and engaged so as to be movable in the A and B directions. A magnetic scale 9a is provided on the rod 9 parallel to the axis of the rod 9, and a magnetic sensor 10 for reading the scale 9a is provided on the rotary table 3 facing the magnetic scale 9a. In the vicinity of the excavation part 9b of the rod 9 in the lower part of the figure, there are provided an ultrasonic sensor 11, which is a means for transmitting and receiving ultrasonic waves for distance measurement, consisting of an ultrasonic oscillator and a receiver, and an injection nozzle 9c that injects high-pressure water. Furthermore, an ultrasonic sensor 12 is provided, which is a means for transmitting and receiving correction ultrasonic waves, and includes a correction ultrasonic oscillator and a receiver. Reflective materials 13,
15 is attached to the tip of the plunger magnets 16, 17, and the reflective materials 13, 1
5 can be selectively projected in the directions of arrows C and D by selectively driving plunger magnets 16 and 17. Note that a bit 9d is attached to the lower end of the excavation portion 9b.

On the other hand, as shown in FIG. 3, the rotation angle meter 6, the magnetic sensor 10, and the ultrasonic sensors 11 and 12 are connected to a rotation angle calculation section 19, an excavation depth calculation section 20, and an excavation diameter calculation section 21. and each calculation unit 19, 2
0 and 21 are connected to the main control section 22. The main control unit 22 includes a display 23 and a keyboard 25.
is connected.

Since the underground excavation equipment 1 has the above configuration, when excavating the excavation hole 26 etc. by ground modification etc., the motor 7 is rotationally driven and the spur gears 7a,
5b, shaft 5, and bevel gears 5a and 3a, the rotary table 3 is rotated in the direction of arrow E in FIG. Then, the rod 9 also rotates together with the table 3, and the bit 9d at the lower end of the excavated portion 9b also rotates, and by the weight of the rod 9, the excavated hole 26 is gradually excavated downward in the figure. The earth and sand generated during excavation is turned into muddy water slurry together with the water 27 injected into the excavation hole 26, and the hollow part 9 of the rod 9 is
It is discharged to the outside through e.

When the excavation reaches a predetermined depth, high-pressure water 30 is injected from the injection nozzle 9c, and the impact force of the high-pressure water is used to blow the ground 2 around the excavation part 9b.
Drill 9. At this time, the rotation of the rotary table 3 and therefore the rod 9 continues, so that the ground is moved by the high pressure water 30 as shown in FIG.
An excavated hole 31 is excavated in a circular planar shape and has a larger diameter than the excavated hole 26.

Once the drilled hole 31 is formed, the drilled holes 26, 31
Consolidation material is injected into the ground to form a cylindrical artificial ground in the ground 29. At this time, the depth DP of the drilled holes 26 and 31 from the ground surface 29a and the excavation shape of the drilled hole 31 are accurately determined. This is an essential condition for reliable ground modification.

That is, as the progress of excavation of the boreholes 26 and 31 is determined, the rod 9 descends in the direction B, and the amount of descent corresponds to the depth DP of the boreholes 26 and 31 at that point. Therefore, the rod 9 is detected by the magnetic sensor 10.
The excavation depth DP can be easily determined by reading the upper magnetic scale 9a and calculating the corresponding depth using the excavation depth calculation section 20.

The shape of the drilling holes 26 and 31 is similar to that of the ultrasonic sensor 11.
It is determined from the reflected wave 32a of the ultrasonic wave 32 emitted from the ultrasonic wave 32 and the emission angle of the ultrasonic wave 32. That is, the emission angle α of the ultrasonic wave 32 is equal to the rotation angle α of the rod 9, and the rotation angle α is transmitted through the rotary table 3, which rotates in synchronization with the rod 9, and the rotation angle meter 6 and the rotation The angle calculation unit 19 calculates and determines the angle. Further, the ultrasonic waves 32 emitted from the ultrasonic sensor 11 are transmitted to the walls 26 of the boreholes 26 and 31.
a, 31a, and is incident and captured by the sensor 11 again. Therefore, by measuring the time from when the ultrasonic wave 32 is emitted until it is incident, the sensor 1
The distance LW1 from 1 to the wall surfaces 26a, 31a, therefore from the hole center 26b, 31b to the wall surfaces 26a, 31
(The rod 9 is installed with its axis aligned with the hole centers 26b and 31b, and the sensor 11 is fixed at a constant distance from the rod axis. The figure shows wall surface 3
Only the distance to 1a is shown. ).

By the way, from the sensor 11 to the excavation radius calculation unit 21
The reflected wave signal SG output to the
In order to remove such noise 33, the calculation unit 21
sets a certain threshold value SHL, measures the time T3 from the emission of the ultrasonic wave 32 to the rising point P1 of the signal exceeding the threshold value SHL, and calculates the distance. However, originally, when determining the distance from an object by capturing the reflected waves of ultrasonic waves, the reflected waves 32a
Since the accurate distance cannot be determined unless it is determined by the time T1 from the original rising point P2 of , it is necessary to determine the time T2 (or the corresponding distance LX) from point P2 to point P1.

Therefore, prior to measurement, first, the main control section 22 is commanded to execute a correction operation via the keyboard 25. Then, the main control section 22 drives the plunger magnet 16 to cause the reflective material 13 set at a predetermined distance LC from the correction ultrasonic sensor 12 to protrude in the D direction. Next, an ultrasonic wave 32 is emitted from the sensor 12, and its reflected wave 32a is captured. At this time, the reflected wave signal SG of the sensor 12 becomes as shown in FIG. 5, the reflected wave 32a rises at point P2, exceeds the threshold value SHL at point P1, is captured by the calculation unit 21 as time T3, Therefore, the distance LC from the sensor 12 to the reflective material 13 is apparently the distance
Measured as LCA.

LCA=LC+LX...(1) (T3=T1+T2)...(1a) Next, the plunger magnet 17 is driven instead of the plunger magnet 16 to move the reflective material 13 back in the C direction, and the reflective material 15 to protrude in the D direction. The distance LD between the reflective material 15 and the sensor 12 is
Since the distance between the reflective material 13 and the sensor 12 is set to twice the distance LC, the reflected wave signal SG becomes as shown in FIG. In this case, the distance LD is apparently measured as the distance LDA.

LDA=2LC+LX ...(2) (T4=2T1+T2) (2a) Therefore, from equation (1), substitute LC=LCA−LX into (2), LDA=2(LCA−LX)+LX =2LCA− LX ∴LX=2LCA−LDA ...(3) That is, T2=2T3−T4 ...(4) By measuring the time T3 and T4 to each point P1 on the reflective materials 13 and 15, the time T2 is required immediately.

The calculation unit 21 corrects the actual measurement result by the sensor 11 using the time T2 obtained in this way or the distance LX corresponding to it, and calculates the accurate distance LW.
1. Find LW2. Obtained distance LW1, LW
2 is output to the main control section 22 along with the emission angle α of the ultrasound at that time calculated and determined by the rotation angle calculation section 19, and the main control section 22 displays on the display 23,
As shown in Fig. 4, a point XP is placed at a position corresponding to distance LW2 rotated by an angle α from the reference position
Display.

In this way, when the angle α and the distance LW2 are continuously determined and displayed on the display 23, the planar shapes of the excavated holes 26 and 31 are accurately displayed on the display 23 as a collection of points XP. Note that the excavation depth DP is displayed as a numerical value on the display 23.

Further, in the above embodiment, two reflective materials 13, 1
5, a case has been described in which a transmitting/receiving means such as one correction ultrasonic sensor 12 is provided, but it goes without saying that the transmitting/receiving means may be provided along each of the reflecting materials 13 and 15, respectively. Furthermore, reflective material 1
3 and 15 do not need to be used exclusively for reflecting ultrasonic waves, and it is also possible to use parts on the rod 9 for other purposes as the reflecting materials 13 and 15.

Further, the distances LC and LD from the reflective materials 13 and 15 to the ultrasonic sensor 12 do not necessarily have to be 2LC=LD, and may be set to any distance as long as they have a certain length ratio. That is, now, if N.
When LC=LD, equations (3) and (4) become LXLDA-N・LCA/1-N...(3)'T2=T4-N・T3/1-N...(4)' Become.

(f) Effect of the Invention As explained above, according to the present invention, one or more correction ultrasonic wave transmitting/receiving means such as the ultrasonic sensor 12 is provided on the rod 9 near the excavation part 9b, and at least two Since the reflective materials 13 and 15 are installed so as to be able to protrude and retract freely relative to the rod 9 and have different distances LC and LD from the correction ultrasonic wave transmitting/receiving means, it is possible to excavate using ultrasonic waves. Distance LW1, LW2 such as radius of holes 26, 31
Corrections for measurements such as the above can be easily performed without preparing correction equipment outside the excavation rig 1. Furthermore, since both the correction ultrasonic wave transmitting/receiving means and the ranging ultrasonic wave transmitting/receiving means are installed near the excavation part 9b, when drilling the boreholes 26 and 31, both of them are in the same medium such as muddy water slurry. , the surrounding conditions are approximate, and therefore accurate correction values such as time T2 or distance LX can be obtained, and accurate calculation and measurement of distances LW1, LW2, etc. can be performed. In addition, since the reflective materials 13 and 15 are provided so as to be able to protrude and retract from the rod 9, the reflective materials 13 and 15 can be kept retracted from the rod 9 except when performing a correction operation. Therefore, it is possible to reduce the risk of the reflective material being damaged by the earth and sand in the muddy water slurry, and it is possible to perform appropriate correction operations over a long period of time. Furthermore, since the reflecting materials 13 and 15 and the correction ultrasonic wave transmitting/receiving means are provided on the rod 9, the farthest position from the wall surface 31a excavated by the excavation water,
In other words, the reflective material 13, 1 can be located at a position where the density of sediment floating in muddy water is the lowest.
5 and the correction ultrasonic wave transmitting/receiving means from being damaged by excavated soil, it is possible to provide a highly reliable underground excavation apparatus 1.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the underground excavation apparatus according to the present invention, FIG. 2 is a partial sectional view of the vicinity of the excavation part of the underground excavation apparatus shown in FIG. 1, and FIG. 3 is a front view of the underground excavation apparatus shown in FIG. FIG. 4 is a plan view showing the method of distance measurement of an excavated hole using ultrasonic waves, and FIGS. 5 and 6 are time charts showing the method of correction using ultrasonic waves for correction. DESCRIPTION OF SYMBOLS 1... Underground excavation equipment, 9b... Excavation part, 9d... Bit, 11... Ultrasonic transmission/reception means for ranging (ultrasonic sensor), 12... Transmission/reception means for correction ultrasonic waves (ultrasonic sensor), 32... Ultrasonic waves , 13, 15...Reflector, LC, LD...Distance, 9...Rod, 9c...Drilling water jetting means (injection nozzle), 29...Ground, 30...Drilling water (high pressure water).

Claims (1)

[Claims] 1. It has a rod that can be freely rotated and is provided with an excavation part with a bit attached to the tip of the rod, and an excavation water spouting means for spouting excavation water toward the surrounding ground, and furthermore, the excavation A distance measuring ultrasonic wave transmitting/receiving means is provided near the area, and the distance measuring ultrasonic wave transmitting/receiving means can measure the shape of the surrounding ground excavated by the excavation water spouted from the excavation water spouting means. In the underground excavation equipment, one or more correction ultrasonic transmitting/receiving means are provided on the rod near the excavation part, and furthermore, at least two reflecting members are provided so as to be able to protrude and retreat freely with respect to the rod, and Underground excavation equipment configured to be installed at different distances from the ultrasonic transmitting/receiving means.