JPH1037652A - Excavation method of vertical hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly efficiently and accurately excavate a vertical hole of a large diameter and big depth by providing a strut gripper. SOLUTION: A guide pipe 4 is inserted in a preceding excavation hole 1 formed in a deposited layer B, a jack 5 provided on the outer wall is extended and operated to fix the guide pipe 4, an excavator 3 is inserted in the guide pipe 4 to extend the gripper 11, and fixed in the guide pipe 4. Next, after muddy water is supplied in the preceding excavation hole 1, a rock mass layer A is excavated in a slightly wider range than the outside diameter of the guide pipe 4 while the rotation cutter 14 of the excavator 3 is turned and linearly moved and reaction force is taken from the guide pipe 4. At this time, excavated soil and sand are mixed with muddy water to be air-lifted through a mud discharge pipe 20 to the ground, thereafter the jack 5 is shortened to lower the guide pipe 4 on the bottom of an excavation hole 8, and at the position the jack 5 is extended to fix the guide pipe 4. Excavation is performed by the excavator 3 again, and the cycle is repeated down to prescribed depth.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for excavating a pit, and more particularly to an excavation method suitable for excavating a pit having a large diameter and a large depth.

[0002]

2. Description of the Related Art For example, when attempting to use a pit to construct an underground energy storage tank, underground water tank, underground parking lot, or the like, a diameter of several meters to several tens of meters and a depth of several tens to hundreds of tens of meters are used. Excavation of meters of rock is required, and drilling with a general-purpose work machine will not be possible at all.

[0003] Recently, various studies have been made on the use of excavators used in the steel pipe pile driving method described in Japanese Patent Publication Nos. 7-3049 and 8-16433. This excavator has a gripper for striking and a rotary cutter capable of turning and moving linearly. In the method for setting a steel pipe pile described in the above-mentioned publication, the excavator is configured to project the gripper against the inner wall of the steel pipe pile. After the position is fixed, the rotary cutter is turned and linearly moved to excavate a range slightly larger than the outer diameter of the steel pipe pile to a predetermined depth as a reaction force receiver on the inner wall of the pipe, and push the steel pipe pile into the drilled hole. The steel pipe pile is gradually penetrated into the rock. Therefore, if, for example, a large-diameter guide pipe is used instead of the steel pipe pile, a large-diameter hole can be excavated at a time by using the inner wall of the guide pipe as a reaction force receiver. Excavation can be performed efficiently.

[0004]

However, the idea of the conventional excavation method using the above-mentioned excavator is to add and extend a guide pipe in accordance with the excavation depth.
As the excavation depth becomes deeper, it becomes more difficult to fix the position of the guide tube, the function of receiving the reaction force becomes inadequate, and the accuracy (roundness, inclination, etc.) of the formed product deteriorates. However, there is a problem that excavation becomes difficult when the object is used. In addition, as a countermeasure, there is a concept of press-fitting the guide pipe by digging the inside of the guide pipe with an excavator, but in this case, separate press-fitting equipment is required,
A new problem occurs in that the construction cost increases.

The present invention has been made in view of the above technical background, and has as its object to provide an excavation method capable of excavating a large-diameter, deep-drained pit with high efficiency and high accuracy.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides an excavator having a gripper for tensioning and a rotary cutter capable of turning and moving linearly in a guide pipe provided with a plurality of jacks on an outer wall. After the excavator is fixed in position by projecting the gripper against the inner wall of the guide tube, the rotary cutter is turned and linearly moved to a predetermined depth slightly larger than the outer diameter of the guide tube. Digging over, and then shortening the jack to sink the guide tube into the hole drilled by the excavator, and extending the jack at this sinking position to extend the guide tube to the inner wall of the hole. After the fixation, the excavator performs excavation again.

In the pit excavation method constructed as described above, the guide pipe can be reliably fixed at any excavation depth by extending the jack, and the excavator can use the excavator while taking a reaction force from the guide pipe. Excavation can be performed stably.

According to the present invention, muddy water can be supplied into a guide pipe, excavated earth and sand by an excavator can be mixed with the muddy water, and can be discharged to the ground through a drainage pipe having a suction opening near a rotary cutter. In this case, it is desirable to supply compressed air to the tip of the mud pipe and discharge excavated earth and sand mixed with muddy water to the ground by an air lift.

[0009]

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

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an initial stage of pit excavation. In FIG. 1, reference numeral 1 denotes a pre-drilled hole formed by pre-drilling a sedimentary layer B on a bedrock A, and its inner wall is protected by a casing 2. This pre-drilling hole 1
Inside, a guide pipe 4 in which an excavator 3 described below is installed is provided. The guide pipe 4 has an outer diameter slightly smaller than the diameter of the preceding excavation hole 1 (in this case, the inner diameter of the casing 2), and extends the plurality of jacks 5 provided on the outer wall thereof to extend the inner wall of the casing 2. The position is fixed.

As shown in FIGS. 2 and 3, the jack 5 comprises a jack body 6 embedded in the wall of the guide tube 4 and a ground plate 7 attached to the tip of an output shaft 6a of the jack body 6. ing. The grounding plate 7 has a curved shape that follows the curved shape of the inner wall of the casing 2 or the inner wall of a rock excavation hole 8 described later, and the front surface of the grounding plate 7 has a front surface corresponding to the extension of the output shaft 6 a of the jack body 6. Or the inner wall of the excavation hole 8. In this case, four jacks 5 are equally arranged in the circumferential direction, and three jacks 5 are equally arranged in the vertical direction. The guide pipe 4 is configured such that all the jacks 5 extend. Accordingly, the position is firmly fixed to the inner wall of the preceding excavation hole 1 or the rock excavation hole 8 in the normal posture. A concave portion 9 is formed on the outer peripheral surface of the guide tube 4 to allow the ground plate 7 to be fitted therein.
When the jack 5 is not operated, the ground plate 7 is housed in the recess 9 so that no step is formed on the outer peripheral surface of the guide tube 4.

The excavator 3 is fixed in position with respect to the guide tube 4 by projecting a plurality of grippers 11 provided on its body 10 against the inner wall of the guide tube 4. The excavator 3 has the same basic structure as that described in Japanese Patent Publication No. 7-3049 or Japanese Patent Publication No. 8-164433, and is rotatable and axially movable on the main body 10. One or two rotary cutters 14 are attached to a drive shaft 12 mounted therein via a tilting arm 13. The drive shaft 12 is rotated and axially moved by independent drive means, and the rotary cutter 14 is driven to rotate by a motor (not shown) provided in the tilt arm 13, and the tilt arm 13 is moved by a tilt cylinder 15. It can be tilted. Tilt cylinder 1
By rotating the drive shaft 12 in a state where the tilt arm 13 is tilted to a predetermined angle by 5, the rotary cutter 14 turns around the axis of the drive shaft 12, and accordingly, the tilt angle of the tilt arm 13 is appropriately changed. Excavation of a wider area than the outer diameter of the guide tube 4 is possible. In addition, by exposing the drive shaft 12 in the axial direction (linear movement) while rotating the rotary cutter 14, excavation at a depth corresponding to the movement range (stroke range) of the drive shaft 12 becomes possible.

On the other hand, on the ground, a gantry 16 is installed above the preceding excavation hole 1. A first support device 19 for suspending and supporting the guide tube 4 via a support tube (steel tube) 18 extending from a lid 17 attached to the upper end of the guide tube 4, and an excavator A second support device 21 for suspending and supporting the exhaust pipe 20 via an exhaust pipe 20 extending from 3 is mounted. The sludge pipe 20 is provided in the support cylinder 1.
8 is extended, and the front end (lower end) is extended to the vicinity of the rotary cutter 14 through the main body 10 of the excavator 3. The tip of the sludge pipe 20 is fixed to the tilting arm 13 that supports the rotary cutter 14 so as to follow the movement of the rotary cutter 14. Are always positioned so as to face around the rotary cutter 14. Note that compressed air is supplied to the distal end of the exhaust pipe 20 through an air pipe (not shown) extending through the support cylinder 18.

When excavating a pit, a pre-drilled hole 1 is excavated in the sedimentary layer B by a general-purpose excavation method such as an open cut, and a casing 2 is fitted into the pre-drilled hole 1 as shown in FIG. Then, the gantry 16 is installed on the ground. The gantry 16 has a sufficient space at its lower part to allow the guide tube 4 to enter and exit, and a pair of rails 21 are laid on the ground in this space so as to extend on both sides of the preceding excavation hole 1. I have.

Next, as shown in FIG. 4, the guide tube 4 is carried into a space below the gantry 16 on a carriage 22 running on a rail 21. Subsequently, the guide tube 4 is lifted by operating a suspension device (not shown) provided on the gantry 16,
After the carriage 22 is retracted, the guide pipe 4 is lowered into the preceding excavation hole 1 by the suspension device. Then, as shown in FIG. 4, the jack 5 is extended at an appropriate sinking position,
The guide tube 4 is fixed to the casing 2.

Next, as shown in FIG. 4, a casing 23 for accommodating the excavator 3 is provided, a gripper 11 is extended in the casing 23, and a bogie 24 on which the excavator 3 is fixed in advance is moved on the rail 21. The excavator 3 is carried into the lower space of the gantry 16. Subsequently, by operating the suspension device provided on the gantry 16, the excavator 3 with the gripper 11 contracted is lifted, and the excavator 3 is lowered into the guide pipe 4 through the carriage 24. At first, as shown in FIG. 5, the excavator 3 is positioned on the upper side in the guide tube 4 and its gripper 1
The excavator 3 is fixed in position by projecting the extruder 1 against the inner wall of the guide tube 4. After the fixing of the position of the excavator 3 is completed, the bogie 24 retreats after the lifting of the suspension device.

Thereafter, as shown in FIG.
A cover 17 is placed on the excavator 4 while extending the support tube 18 upward from the cover 17 and passing through the support tube 18.
, The sludge pipe 20 and an air pipe (not shown) are extended upward. The support tube 18 is supported by the first support device 19 on the gantry 16, while the sludge pipe 20 and the air pipe are supported by the second support device 21 on the gantry 16.
The end of the sludge pipe 20 is connected to a sludge hose extending from a sludge pond, and the end of an air pipe is connected to an air hose extending from an air compressor.

After the completion of the preparation, muddy water is supplied into the pre-drilled hole 1 (guide pipe 4), and excavation of the bedrock A is started. In this excavation, as described above, the rotary cutter 14 of the excavator 3 is swiveled and linearly moved to excavate a range slightly larger than the diameter of the guide pipe 4, and the excavated earth and sand are mixed with the muddy water and passed through the drainage pipe 20. Discharge to mud pond by air lift. When excavation at a depth corresponding to the moving range (stroke range) of the drive shaft 12 is completed, the drive shaft 12 of the excavator 3 is moved upward to position the rotary cutter 14 at the rising end, and the gripper 11 is moved. The excavator 3 is retracted to release the fixation, and the excavator 3 is lowered to the lower side of the guide tube 4 by the operation of the second support device 21 as shown in FIG. next,
At that position, the gripper 11 is extended to fix the excavator 3 with respect to the guide tube 4, and the rotary cutter 14 is again turned and linearly moved to perform excavation.

When the excavator 3 finishes excavating to a predetermined depth with the guide tube 4 fixed in position in this way, the jack 5 is contracted to release the fixation of the guide tube 4, and the first support device 19 is released. The guide tube 4 is drilled by the operation of the hole 8 (FIG. 1).
Settle to the bottom. Then, the jack 5 is extended again at the sunk position to fix the position of the guide tube 4 to the inner wall of the excavation hole 8, and then, the excavator 3 is first placed on the upper side of the sunk guide tube 4. Is positioned and fixed (the same state as in FIG. 5). Thereafter, excavation is performed in the same procedure as described above, the guide pipe 4 is settled in the newly excavated hole 8, and this cycle is repeated continuously. This allows
As shown in FIG. 5, a large-diameter, large-depth excavation hole 8 is formed in the bedrock A. When excavation to a predetermined depth is completed, excavation work is stopped, and the guide pipe 4 and the excavator 3 are moved to the ground. Pull up.

According to this method, the jack 5 is extended to fix the position of the guide tube 4 just above the excavation area.
Regardless of the excavation depth, the guide pipe 4 functions sufficiently as a reaction force receiving excavation by the excavator 3, and can excavate smoothly even in the hard rock layer A, and also satisfies the shape of the excavation hole 8. Becomes Note that, depending on the depth of the excavation hole 8, the support cylinder 1
Needless to say, the 8 and the exhaust pipe 20 are added.
The muddy water supplied into the excavation hole 8 is managed so as to be always constant.

In the above embodiment, the guide pipe 4 and the excavator 3 are separately carried into the excavation area. However, the excavator 3 is fixed in the guide pipe 4 in advance, and the two are integrated into the excavation area. It may be carried in. Further, in the present invention, the preceding excavation hole 1 may be excavated using the guide tube 4 and the excavator 3, and in this case, the guide tube 4 is placed on the ground using appropriate fixing means. The position is fixed, and excavation by the excavator 3 is performed using this as a reaction force receiver. In the present invention, the guide tube 4 may be formed to be extendable and contractable. In this case, the cutting range of one cycle is extended, and the cutting efficiency is further improved.

[0022]

As described above in detail, according to the pit excavation method of the present invention, a pit having a large diameter and a large depth can be excavated with high efficiency and high accuracy, and the underground storage of energy can be performed. It can be applied not only to construction of tanks, underground water tanks, underground parking lots, etc., but also to construction of starting bases for shields, foundations of piers, etc., and exerts a great effect.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an initial stage of a pit excavation method according to the present invention.

FIG. 2 is a sectional view showing the structure of a guide tube used in the present invention.

FIG. 3 is an enlarged sectional view of a portion X in FIG. 2;

FIG. 4 is a schematic view showing a construction procedure of the present invention.

FIG. 5 is a schematic view showing a construction procedure of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Excavator 4 Guide pipe 5 Jack 8 Drilling hole 11 Gripper 12 Drive shaft 13 Tilt arm 14 Rotary cutter 17 Lid 18 Support tube 20 Drainage pipe A Bedrock layer B Deposit layer

Claims (3)

[Claims] 1. An excavator having a gripper for tensioning and a rotary cutter capable of turning and moving linearly is inserted into a guide pipe provided with a plurality of jacks on an outer wall, and the gripper projects from the inner wall of the guide pipe. After stretching and fixing the position of the excavator, the rotary cutter is turned and linearly moved to excavate a range slightly larger than the outer diameter of the guide tube over a predetermined depth, and then the jack is shortened. The guide pipe is sunk in the digging hole of the excavator, and the jack is extended at the sunk position to fix the guide pipe to the inner wall of the digging hole, and then the digging by the excavator is performed again. Pit excavation method. 2. A muddy water is supplied into a guide pipe, and excavated earth and sand by an excavator is mixed with the muddy water and discharged to the ground through a mudpipe having a suction port near a rotary cutter. Item 6. The pit excavation method according to Item 1. 3. The method for excavating a pit according to claim 2, wherein compressed air is supplied to the tip of the drainage pipe, and excavated earth and sand mixed with muddy water is discharged to the ground by an air lift.