JPH0543811B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an excavation method for constructing an underground continuous wall.

[Conventional technology]

As is well known, an underground continuous wall is constructed by inserting a reinforcing bar cage into a horizontally long circular hole and pouring concrete to form a single element panel, which is then continued in the length direction. .

There are various methods of excavating a horizontally long circular hole for constructing an underground continuous wall, but one example is shown in Fig. 4. Guide holes 1 are formed in advance at intervals using an earth auger, etc. A gap between the guide holes 1 is excavated with a hydraulic clam shell bucket 3 whose tip trajectory of a shell blade 2 opens and closes horizontally.

In the case shown, a reverse circulation drill method is used. A hydraulic clam shell bucket 3 is attached to the tip of a reverse drill pipe 4, and its opening/closing action scrapes the ground, picks up excavated soil, and discharges it. It is continuously discharged to the ground together with a stabilizing liquid by a drill pipe 4 and a suction pump 5 without soiling. 6 in the figure is a crane that suspends the drill pipe 4 and clam shell bucket 3.
The guide hole 1 is excavated with a drilling bit of a reverse circulation drill, and then the drilling bit is replaced with a clam shell bucket belt 3 and trench excavation is performed.

[Problem to be solved by the invention]

In the conventional excavation method in which such a guide hole 1 is previously excavated and a trench is excavated between them using a clamshell bucket 3, two types of excavators must be converted to one for guide holes and one for trench excavation. , it is troublesome, the process is complicated, and the construction period is long.

In addition, it is difficult to excavate in hard ground such as bedrock, where there are boulders and boulders, and in addition, when digging a deep hole, it is easy to bend when excavating a guide hole or trench hole, so it is difficult to create a straight hole. It's difficult.

The purpose of the present invention is to eliminate the disadvantages of the conventional example,
The reverse circulation drill system speeds up soil removal and improves work efficiency, while also providing high excavation performance that can reliably excavate any ground, from soft ground to hard ground such as cobblestone, boulder, and rock layers. To provide an excavation method capable of greatly shortening the construction period by enabling continuous excavation of horizontally oblong circular holes in one step while maintaining excavation precision that enables straight excavation even at great depths.

[Means to solve the problem]

In order to achieve the above object, the present invention comprises a rotary casing having a cutting blade at its tip, and a ring-shaped digging bit protruding from the tip of the rotating casing and having a shaft connected to the inside near the tip of the rotating casing. The first drilling rigs are connected by a spacing holder that holds the outer periphery of the casing and arranged side by side, and the first drilling rigs are arranged with the same width and horizontally long drilling diameter so as to straddle the upper part of the ring-shaped drilling bit. A second drilling device with a horizontal spiral bit having a drive section supported by the spacing holder is provided, and either one of the injection rod and the reverse rod is connected to the first drilling device through a swivel. The other rod connects to the shaft of the drilling bit between the devices and opens at the tip of the shaft, and the other rod opens at the top of the helical bit of the second drilling device, and connects to the left and right circular guide holes in the first drilling device. A second drilling device is used to drill between these circular guide holes to expand them into horizontally oblong circular holes, and the excavated waste is collected from the reverse rod by stirring the stabilizing liquid from the injection rod. This is a summary.

[Effect]

According to the present invention, in the first drilling device, since the shaft portion of the drilling bit is connected to the inner side near the tip of the rotating casing, the rotation of the casing is transmitted and the drilling bit protruding from the tip of the casing also rotates. A drilling bit is used to excavate the hole in a circular manner, and the outer periphery is further excavated by the excavating blade at the tip of the casing to form circular guide holes on the left and right sides.

Then, the spiral bit of the second drilling device, which is driven by the drive unit provided in the spacing holder that holds the first drilling devices, excavates between these circular guide holes, forming horizontally oblong circular holes at once. .

At the same time, a stabilizing liquid such as bentonite is poured into the hole from the injection rod, and the excavated soil mixed with this stabilizing liquid is mixed and discharged upward by the reversing rod.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 1 is a front view showing one example of the excavation rig used in the construction method of the present invention.First, to explain the first excavation rig, 15 in the figure is a casing made of steel pipe, which can be extended in the length direction as necessary. A plurality of them are connected, and a digging blade 16 is provided at the tip.

In the figure, reference numeral 17 denotes a ring-shaped drilling bit with two or three wings whose drilling diameter with the drilling blade 18 is the same as that of the casing 15.
A stirring blade/guide blade 20 having a vertical blade 20b formed on the outer edge of a screw blade 20a is protrudingly provided in the middle of the screw blade 9.

Furthermore, the upper part of the stirring blade/guide blade 20 was fixed to the inner side of the casing 15 near the tip via a connecting member 21 in the middle of the shaft portion 19 .

In addition, a shaft portion 19 protruding from this connecting member 21
The upper end of the rotary casing 1 is connected to the rotating casing 1 via a swivel 22.
The shaft portion 19 is hollow and has a discharge port 24 communicating with the injection rod 23 at its lower end.

In this first excavation device, the outer periphery of the casing 15 is connected by a spacer 31 which is rotatably held by a stabilizer 30, and arranged side by side.

A housing 33 with an open bottom was provided at the center of the connecting arm 32 of the spacing holder 31, and a submersible motor 34 as a second driving part of the excavation device was installed inside the housing 33.

A holder 3 extending downward from the housing 33
Horizontal screw drum type spiral bits 36 are arranged side by side on the left and right, with a drive shaft 36a being pivotally supported by the screw drum 5, and the spiral bits 36 are hollow and their ends are connected to the upper part of the ring-shaped drilling bit 17 between the first drilling equipment. It extends so that it straddles the upper part of the ring-shaped drilling bit 17 as a whole. The spiral bit 36 has the same width as the ring-shaped drilling bit 17 and a laterally elongated drilling diameter, and in this case, the stirring blade/guide blade 2
0 is positioned so that it partially enters into the spiral bit 36.

Further, the rotation shaft 37 of the underwater motor 34 passes through the holder 35 and is connected to the drive shaft 36a of the spiral bit 36 via a gear 38.

The housing 33 has a reverse rod 25.
The rod 25 communicates with the lower opening of the housing 33, and the stabilizer injection rod 23
is connected to the stabilizing liquid injection plant 26 as shown in the figure, and the reverse rod 25 is connected to this injection plant 26 via a mud screen 27.
to form a circulation path.

Although not shown, in another embodiment, the stabilizing liquid injection rod is placed in the position of the reverse rod 25, the reverse rod is placed in the position of the injection rod 23, and the lower end of the shaft portion 19 is sucked into the reverse rod. It is also possible to use it as a mouth.

Next, the construction method of the present invention using the above device will be explained.

First, the casing installation device will be explained. In FIG. by leader mast 1
3, it is supported so that it can be raised and lowered freely.

Note that this casing erection machine 7 is not a base machine type having a moving mechanism, but may be a stationary type, and may be of a stationary type, and the lifting jack 12 is used as a leg.

The casing 15 is set on this casing erection machine 7, but the shaft part 19 of the ring-shaped drilling bit 17 is fixed to the inside near the tip by the connecting member 21, and the rotary casing 15 and the drilling bit 17 are integrated. , and the drilling bit 17 projects from the tip of the casing 15 via this shaft portion 19.

Casing drive unit 11 of casing erection machine 7
When the motor 8 is started, the chuck mechanism 10 rotates via the reducer 9, and the casing 15 held by the chuck mechanism 10 slowly rotates in one direction.

When the casing 15 is rotated in this manner, the ring-shaped drilling bit 17 protruding from the tip of the casing 15 also rotates, and the ring-shaped drilling bit 17 is rotated first.
The underground is excavated in a circular manner, and the excavation blade 16 at the tip of the casing 15 is further excavated to form circular guide holes A on the left and right sides as shown in FIG.

On the other hand, in the second excavation device, the rotation of the rotating shaft 37 rotated by the underwater motor 34 is transmitted to the drive shaft 36a of the spiral bit 36 via the gear 38, and the spiral bit 36 rotates. Then, a spiral bit 36 is used to drill a rectangular hole between the circular guide holes A, as shown in FIG. 2B, so that horizontally oblong circular holes C can be formed all at once.

At the same time, a stable liquid such as bentonite liquid is pumped from the stable liquid injection plant 26 to the stable liquid injection rod 23, and is poured out from the discharge port 24 at the lower end of the shaft portion 19 of the ring-shaped drilling bit 17. This stabilizing liquid fills the excavation section, and the excavated soil and the stabilizing liquid are mixed by the stirring blade/guide blade 20, collected by the reverse rod 25, and discharged, and then further removed by the mud screen 27.
The earth and sand are removed and the stabilizing liquid is recovered to the stabilizing liquid injection plant 26.

Excavated earth and sand are discharged while circulating the stabilizing liquid.

〔Effect of the invention〕

As described above, by adopting the reverse circulation drilling method, the excavation method of the present invention increases the speed of soil removal and improves work efficiency, and also allows the first excavation device and the second excavation device to be connected to each other. By combining these, it is possible to continuously excavate oblong circular holes for underground continuous walls in one process, thereby significantly shortening the construction period.

Furthermore, the first drilling device transmits the rotation of the casing to the drilling bit, and excavates in two stages: drilling with the drilling bit and excavating with the casing.
It exhibits high excavation performance that can reliably excavate any type of ground, including hard ground such as boulder layers and bedrock layers. In particular, there is no need for a driving device for the drilling bit in addition to the driving device for the casing, making it an inexpensive device, and the accuracy of erecting the casing directly affects the drilling accuracy of the drilling bit, so even at great depths, the overall drilling accuracy can be straightened. High excavation accuracy can be obtained.

[Brief explanation of the drawing]

Figure 1 is a front view showing an example of the excavation equipment used in the construction method of the present invention, Figure 2 is an explanatory diagram showing the trajectory of excavation, Figure 3 is a side view of the casing erecting machine, and Figure 4 is a side view of the casing erecting machine.
The figure is a side view showing a conventional example. 1...Guide hole, 2...Ciel blade, 3...
Hydraulic clam shell bucket, 4... Drill pipe, 5... Sanction pump, 6... Crane, 7... Casing construction machine, 8... Motor,
9...Reduction gear, 10...Chuck mechanism, 11...
Casing drive unit, 12... Lifting jack, 13
...Leader mast, 15...Casing, 16...
...Drilling blade, 17...Ring-shaped drilling bit, 18...
...Drilling blade, 19...Shaft portion, 20...Stirring blade/guide blade, 20a...Screw blade, 20b...Vertical blade, 21...Connecting member, 22...Swivel, 2
3...Rod for stabilizing liquid injection, 24...Discharge port, 2
5... Reverse rod, 26... Injection plant, 27... Matsudo screen, 30... Stabilizer, 31... Spacing holder, 32... Connection arm, 33... Housing, 34... Submersible motor, 35 ... Holding body, 36 ... Spiral bit, 36
a... Drive shaft, 37... Rotation shaft, 38... Gear.

Claims (1)

[Claims] 1. A first drilling device consisting of a rotating casing having a cutting blade at the tip and a ring-shaped drilling bit having a shaft connected to the inner side near the tip of the rotating casing and protruding from the tip of the rotating casing is installed around the outer periphery of the casing. A second drilling device is connected by a spacing holder and arranged side by side, and a second drilling device is formed by a horizontal spiral bit having the same width and a horizontally long drilling diameter so as to straddle the upper part of the ring-shaped drilling bit between the first drilling device. A drilling rig is provided with its driving part supported by the spacing holder, and either one of the injection rod and the reverse rod is connected to the shaft of the drilling bit between the first drilling rig via a swivel. The two rods are connected to each other and open at the tip of the shaft, and the other rod opens at the top of the spiral bit of the second drilling rig, forming left and right circular guide holes in the first drilling rig, and forming the left and right circular guide holes in the second drilling rig. This excavation method is characterized by excavating between these circular guide holes and expanding them into horizontally oblong circular holes, and collecting the excavated waste from the reversing rod by stirring the stabilizing liquid from the injection rod.