JPH11141257A - Digging construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To press in a casing vertically, necessitate no large-sized device, and facilitate the construction even when digging down to a large depth is done and the digging casing is pressed in on a sharp slope. SOLUTION: In this digging construction method, a digging casing 3 is rotated, is pushed forward, and is inserted into the ground by chucking outer periphery by a chuck device provided in a rotary casing pressing in machine 1. In this case, a down-the-hole hammer 9 is inserted into the casing erected vertically, and a guide stabilizer 12 attached to a drill rod 11 of the down-the-hole hammer 9 is brought in contact with an inner peripheral face of the casing 3 to dig the ground previously by the down-the-hole hammer 9 using the casing 3 as a guide through the guide stabilizer 12. After the ground is digged down to a predetermined depth, the casing 3 is rotated and is pushed forward using the drill rod 11 of the down-the-hole hammer 9 as a guide, and the down-the hole hammer 9 is removed after that, and the casing 3 is further rotated and is pushed forward to dig the ground.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling method using a drilling casing.

[0002]

2. Description of the Related Art One type of cast-in-place pile method is an all-casing method. This method uses a large-diameter casing and enables drilling of large-diameter holes even on hard rock or rocky rock. A rotary casing press-fitting machine comprising a chuck device 2 for tightening the outer periphery of the device, a drive device such as a motor and a reduction gear for rotating the chuck device 2 and a hydraulic cylinder for vertically moving the chuck device 2 and the drive device. Use 1.

FIG. 8 to FIG. 12 show a general work process in cast-in-place pile construction. First, as shown in FIG. 8, after setting the ground, the rotary casing press-fitting machine 1 is set on the pile core, and the outrigger jack 1a is set. Use vertical and vertical.

Next, as shown in FIG. 9, the outer periphery of the first casing 3 is fastened and fixed by a chuck device 2 provided in the rotary casing press-fitting machine 1, and the chuck device 2 is rotated by a driving device, and at the same time, a lifting cylinder is moved. And press-fit the casing 3 into the ground. The chuck device 2 is a device for fastening the outer periphery of the casing 3 in a ratchet shape. For example, as shown in FIG.

[0005] The casing 3 is continuously rotated to drill holes and press in, and a hammer grab 4 suspended by a crawler crane or the like is inserted into the casing 3 from above as excavating means to excavate and discharge the earth. Such excavation and earth removal can be performed by the hammer grab 4 even on a hard ground such as a bedrock because the inside of the casing 3 is a portion cut from the ground in a core shape.

When the casing 3 is excavated to a predetermined depth while adding the casing 3, a reinforcing cage 5 is inserted as shown in FIG. 10 and concrete is poured with a tremy tube 6, and then the casing 3 is fixed as shown in FIG. The drawing is repeated one stroke at a time while rotating in the reverse direction (swinging), and the process is completed when the entire casing 3 is pulled out from the ground as shown in FIG.

[0007]

The casing 3 has to be press-fitted vertically along the axis of the shaft.

Also, when the casing is pressed into a rock layer on a steep slope, it is difficult to obtain verticality because only a part of the lower end of the casing is pressed into contact with the rock layer. Conventionally, as a method to cope with this, the casing is adjusted by rotating and pressing the casing by a delicate operation of the operator to obtain verticality, blasting a part of a steep slope or grabbing
Excavating with a breaker or the like in advance and finishing it flat,
Guide materials (guide materials) are installed on steep slopes to prevent slippage, and reference holes are formed and used as guides.

[0009] However, in the method by the operator, the inclination angle that can be dealt with by an artificial operation technique is small, and it is difficult to deal with a steeply inclined surface. In addition, in the case of the sea, it is difficult to grasp the state of the underwater, and there is no other way but to rely on the intuition of the operator, and the accuracy is not good.

In the method of installing the guide material (guide material), it is necessary to install the guide material as close as possible to the ground surface or the sea bottom, but it is difficult in a steep mountain or a seabed with a large water depth.

[0011] Also, the installation of the reference hole is difficult to construct.
In the case of a single pile in which the distance between the piles is large, the guide hardware becomes large and installation is often difficult.

An object of the present invention is to eliminate the disadvantages of the prior art, and even when excavation is performed at a large depth or when a drilling casing is pressed into a steep slope, the casing can be vertically press-fitted. And to provide a drilling method which can be easily constructed.

[0013]

According to the present invention, in order to achieve the above object, first, a drilling casing provided with a drilling blade at a tip thereof is chucked on an outer periphery thereof by a chuck device provided in a rotary casing press-fitting machine. In the drilling method of rotating and inserting into the ground, a down-the-hole hammer is inserted into a vertically built casing, and a guide stabilizer attached to a drill rod of the down-the-hole hammer is brought into contact with the inner peripheral surface of the casing to form the guide. Preliminary excavation of the ground with the down-the-hole hammer using the casing as a guide via a stabilizer, and after drilling to a predetermined depth, rotationally propelling the casing using the drill rod of the down-the-hole hammer as a guide via the guide stabilizer, and then removing the down-the-hole hammer, Excavating the ground by further rotating the casing It is an gist and.

Second, the guide stabilizer has a diameter slightly smaller than the inner diameter of the casing, is mounted on the drill rod at appropriate intervals, and a plurality of guide stabilizers are provided so that the down-the-hole hammer is positioned at the core of the casing. .

Third, the lowermost one of the plurality of guide stabilizers to be disposed is attached so that the down-the-hole hammer is positioned at the lowermost end in the casing when the hammer reaches the excavation depth. It is.

Fourth, the gist of the drill rod is to have strength as a guide pole.

According to the first aspect of the present invention, there is provided a rotary casing press-fitting machine which is powerful and is suitable for large-diameter rock excavation but has a large resistance during excavation, and a large-diameter as large as the rotary casing press-fitting machine. No, but the resistance during excavation is relatively small,
Combining a down-the-hole hammer that excels in maintaining accuracy at the start of excavation, when excavating at a large depth or on a steep slope, down-the-hole using the casing and guide stabilizer already pressed or landed by the rotary casing press machine as a guide. Drill with a hammer and drill a guide hole.

At this time, the excavation by the down-the-hole hammer is easy to adjust to the rock at the start,
It is suitable for excavating guide holes because it is less likely to cause misalignment and runout.

After drilling the guide hole, if the drill casing is rotated and press-fitted using the drill rod of the down-the-hole hammer in the casing and the guide stabilizer as a guide, the casing can be vertically built even at a large depth or a steeply inclined surface. it can.

According to the second aspect of the present invention, in addition to the above operation, the guide stabilizer attached to the drill rod of the down-the-hole hammer abuts on the inner wall of the casing, so that the drill rod is securely positioned on the core of the casing. I do. Therefore, with the guide stabilizer as a guide, both the down-the-hole hammer and the casing descend vertically.

According to the third aspect of the present invention, in addition to the above-described operation, the lowermost one of the plurality of guide stabilizers provided is arranged so that when the down-the-hole hammer reaches the excavation depth, the lowermost one in the casing is provided. Since it is located at the lower end, the distance between the front end of the casing and the guide stabilizer at the lowermost end can be minimized, and misalignment due to slippage and runout at the start of excavation of the casing can be minimized.

According to the fourth aspect of the present invention, in addition to the above operation, the drill rod is given strength as a guide pole, so that a dedicated guide pole is separately inserted into the guide hole drilled by the down-the-hole hammer. It is not necessary to perform the operation, and a difficult insertion operation can be omitted.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 7 are explanatory views of each step showing an embodiment of the excavation method of the present invention.

The rotary casing press-fitting machine 1 used in the excavation method of the present invention is provided with a chuck device 2 and the like as in the prior art. First, as shown in FIG. 1, and two guides 8 for supporting the casing 3 are provided at opposing positions. The guide 8 has a plurality of rollers in the circumferential direction of the casing 3.

Then, the casing 3 is set on the rotary casing press-fitting machine 1 and fastened by the chuck device 2, and the rotary casing press-fitting machine 1 is centered, and the casing 3 is built.

In this case, since the casing 3 is built along the guide 8, the verticality is maintained.
The swing of the casing after being erected is restrained by the two guides 8 arranged at the opposing positions, and is maintained at a predetermined position.

When the casing 3 is pressed into a large depth,
In order to press-fit into a steep slope, for example, as shown in FIG. 2, the casing 3 is lightly contacted with the rock surface so as not to promote slipping or tilting. When the casing 3 slides due to a large inclination of the rock surface, the contact does not have to be made.

As shown in FIG. 3, a rotary table 10 for rotating the down-the-hole hammer 9 is set on the head of the casing 3, and the down-the-hole hammer 9 is an air-driven hitting machine.
Is hung from a crawler crane or the like and built into the casing 3. In the drawing, reference numeral 11 denotes a drill rod which also serves as a guide pole of the down-the-hole hammer 9.

As is well known, the drill rod 11 has a diameter smaller than the inner diameter of the casing 3, has sufficient strength to be used as a guide pole, and has a plurality of guide stabilizers abutting on the inner wall of the casing 3.
Attach 12 at appropriate intervals. Guide stabilizer 12
The guide stabilizer 12 has a diameter slightly smaller than the inner diameter of the casing 3 and is attached to the drill rod 11 at appropriate intervals.
The spoke-shaped member protruding from 11 supports a ring slightly smaller in diameter than the casing 3.

In this case, the lowermost one of the plurality of guide stabilizers 12 is disposed on the casing 3 when the down-the-hole hammer 9 reaches the excavation depth as described later.
Attach it so that it is located at the lowermost end.

By driving the down-the-hole hammer 9 inserted in the casing 3 in this way, as shown in FIG. 4, the deep rock or the steeply sloped rock is excavated by the down-the-hole hammer 9 using the casing 3 as a guide via the guide stabilizer 12. And excavate the guide hole. Since the excavation with the down-the-hole hammer 9 is of a rotary percussion type, it is easy to adjust the contact with the rock surface at the start of excavation, and it is unlikely to cause misalignment or runout.

Further, since the down-the-hole hammer 9 is an excavator that does not easily generate an unbalanced load, the casing 3 can function as a guide even in a cantilever state where the casing 3 is not deposited on the rock surface.

Further, since the guide stabilizer 12 is attached to the drill rod 11 of the down-the-hole hammer 9, the guide stabilizer 12 guides the down-the-hole hammer 9 to the center position of the casing 3, and smoothly moves the casing 3 without eccentricity. Rotate with.

In this manner, as shown in FIG. 5, the guide hole is excavated by, for example, about 3 to 4 m by the down-the-hole hammer 9 until the lowermost guide stabilizer 12 is located at the lowermost end in the casing 3. As described above, the excavation is performed by using the guide stabilizer 12 in the casing 3 as a guide.
When the down-the-hole hammer 9 initially excavates the rock surface, slippage and resistance to the rigidity of the drill rod 11 can be minimized.

After excavation of the guide hole is completed, a drill rod
11 functions as a guide pole and supports the down-the-hole hammer 9 at the excavation completion position.

Next, the casing 3 is rotated and pushed into the ground as shown in FIG. At this time, the drill rod 11 and the guide stabilizer 12 serve as guides to
Is pushed and rotated, and the casing 3 is pushed vertically.

Particularly, since the guide stabilizer 12 at the distal end is located in the casing 3 near the rock surface, it is closest to the support point of the drill rod 11, and the fluctuation of the rotational propulsion of the casing 3 can be effectively suppressed. .

During the rotation of the casing 3 in this step, excavation in the casing 3 is not performed. In this step,
When the excavation in the casing 3 is performed, the casing 3 slides,
This is because there is a possibility that run-out may occur. The pushing without performing the internal excavation of the casing 3 is performed until, for example, 2/1 or more of the diameter of the casing 3 bites into the rock.

As described above, if the casing 3 has cut into the bedrock by a predetermined amount and the subsequent rotary excavation of the casing 3 can be performed in a stable state, as shown in FIG. Is removed, and the casing 3 is rotationally propelled and pushed in.
A digging means such as a hammer grab or chisel is hung by a crawler crane or the like and inserted into the inside of the cradle to excavate the inside.

[0040]

As described above, the excavating method of the present invention
First, a rotary casing press-fitting machine that is powerful and suitable for large-diameter rock excavation, but has a high resistance during excavation, and a rotary casing press-fitting machine that does not have such a large diameter as the rotary casing press-fitting but has relatively low resistance during excavation. By combining a down-the-hole hammer that excels in maintaining accuracy at the start of excavation, when excavating at a large depth or on a steep slope, excavation is performed with a down-the-hole hammer using a casing that has been already press-fitted by a rotary casing press as a guide. Therefore, a guide hole can be easily excavated vertically without requiring large-scale equipment.

Drilling after excavation of the guide hole can be performed by rotating the drill casing using the drill rod of the down-the-hole hammer in the casing as a guide. But the casing can be easily erected vertically.

Further, since the guide stabilizer attached to the drill rod of the down-the-hole hammer abuts against the inner wall of the casing, the drill rod is securely positioned at the core of the casing, and the down-the-hole hammer and the casing are vertically positioned using the guide stabilizer as a guide. Surely descends.

Further, the lowermost one of the plurality of guide stabilizers disposed is located at the lowermost end in the casing when the down-the-hole hammer reaches the excavation depth. Can be minimized, and misalignment due to slippage and runout at the start of casing excavation can be minimized.

Since the drill rod is given the strength as a guide pole, it is not necessary to separately insert a dedicated guide pole into the guide hole drilled by the down-the-hole hammer, and it is possible to omit a difficult insertion work. .

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first step showing an embodiment of an excavation method of the present invention.

FIG. 2 is an explanatory view of a second step showing the embodiment of the excavation method of the present invention.

FIG. 3 is an explanatory view of a third step showing the embodiment of the excavation method of the present invention.

FIG. 4 is an explanatory view of a fourth step showing the embodiment of the excavation method of the present invention.

FIG. 5 is an explanatory view of a fifth step showing the embodiment of the excavation method of the present invention.

FIG. 6 is an explanatory view of a sixth step showing the embodiment of the excavation method of the present invention.

FIG. 7 is an explanatory view of a seventh step showing the embodiment of the excavation method of the present invention.

FIG. 8 is a vertical sectional front view showing a first step of excavation by the all casing method.

FIG. 9 is a longitudinal sectional front view showing a second step of excavation by the all casing method.

FIG. 10 is a vertical sectional front view showing a third step of excavation by the all casing method.

FIG. 11 is a vertical sectional front view showing a fourth step of excavation by the all-casing method.

FIG. 12 is a vertical sectional front view showing a fourth step of excavation by the all casing method.

FIG. 13 is a perspective view showing a chuck device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotary casing press-fitting machine 1a ... Outrigger jack 2 ... Chuck device 3 ... Casing 4 ... Hammer grab 5 ... Rebar cage 6 ... Tremey tube 7 ... Temporary gantry 8 ... Guide guide 9 ... Down the hole hammer 10 ... Rotary table 11 ... Drill rod 12… Guide stabilizer

Claims (4)

[Claims] An excavating method in which a drilling casing provided with a drilling blade at a tip is rotatably propelled while chucking the outer periphery by a chuck device provided in a rotary casing press-fitting machine and is inserted into the ground, and is vertically built. A down-the-hole hammer is inserted into the inside, a guide stabilizer attached to a drill rod of the down-the-hole hammer is brought into contact with the inner peripheral surface of the casing, and the ground is pre-drilled with the down-the-hole hammer using the casing as a guide through the guide stabilizer. A drilling method characterized in that after drilling at a predetermined depth, the casing is rotationally propelled using a drill rod of a down-the-hole hammer as a guide via a guide stabilizer, and then the down-the-hole hammer is removed, and the casing is further rotationally propelled to excavate the ground. 2. The drilling method according to claim 1, wherein the guide stabilizer has a diameter slightly smaller than the inner diameter of the casing and is attached to the drill rod at appropriate intervals to position the down-the-hole hammer at the core of the casing. 3. The excavation method according to claim 2, wherein the lowermost one of the plurality of guide stabilizers is mounted so as to be positioned at the lowermost end in the casing when the down-the-hole hammer reaches the excavation depth. 4. The drilling method according to claim 1, wherein the drill rod has a strength as a guide pole.