JP2023061669A - Ground excavation method - Google Patents

Abstract

To provide a ground excavation method capable of reducing the work period for excavating the bedrock layer.SOLUTION: The ground excavation method includes the steps of: press-inserting a casing 2 while being rotated with a circumference rotating device 1 and excavating the ground G inside the casing 2 with a hammer grab 3 (Fig. 1(a)); excavating the ground G with the hammer grab 3 and when having reached a bedrock layer Gb that the ground G includes, pulling out the hammer grab 3 from inside the casing 2; placing a table machine 4 on the top of the casing 2 (Fig. 1(b)), and inserting a down-the-hole hammer 7 into the casing 2, and rotating the down-the-hole hammer 7 with the table machine 4 to excavate the bedrock layer Gb to a predetermined depth with the down-the-hole hammer 7 (Fig. 1(c)); and after excavating the bedrock layer Gb to the specified depth, inserting the hammer grab 3 into the casing 2, and collecting rock crushing generated during excavation of the bedrock layer Gb.SELECTED DRAWING: Figure 1

Description

The present invention relates to a ground excavation method.

Conventionally, the all-casing construction method is known as a construction method for excavating the ground. In this all-casing construction method, a steel pipe called a casing (or casing tube) with a diameter of about 1 to 3 m is rotated by an excavator and pushed vertically into the ground to dig down the ground. In this method, the ground inside the casing is excavated and discharged with a hammer grab (see, for example, Patent Document 1).

JP-A-08-326018

However, when the ground is excavated using the all-casing construction method as described above, when the rock layer of the ground is reached, the frictional resistance due to tightening of the bedrock layer increases, so it is necessary to push the casing into the bedrock layer. The load for digging down becomes large. Therefore, the all-casing construction method as described above has a problem that the work period for excavating the bedrock layer becomes very long.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a ground excavation method capable of shortening the work period for excavating a rock layer.

The above objects of the present invention are achieved by the following means. In addition, although the inside of parenthesis is attached with the reference code|symbol of embodiment mentioned later, this invention is not limited to this.

According to the first aspect of the invention, the step ( See FIG. 1(a)) and
The ground (G) is excavated by the hammer grab (3), and when the rock layer (Gb) included in the ground (G) is reached, the hammer grab (3) is pulled out from the casing (2), and the casing is A step of installing a table machine (4) on top of (2) (see FIG. 1(b));
By inserting a down-the-hole hammer (7) into the casing (2) and rotating the down-the-hole hammer (7) by the table machine (4), the rock layer (Gb) is removed by the down-the-hole hammer (7). A step of excavating to a predetermined depth (see FIG. 1(c));
After excavating the rock layer (Gb) to the predetermined depth, the down-the-hole hammer (7) is pulled out from within the casing (2), and the table machine (4) installed on top of the casing (2) is removed. Removing and inserting the hammer grab (3) into the casing (2) to recover rock crushing generated when excavating the rock layer (Gb) using the hammer grab (3) ( (see FIGS. 2(a) and 2(b)).

According to the second aspect of the invention, the step of press-fitting the casing (2) while rotating it by the full-circumference rotating device (1) and excavating the ground (G) in the casing (2) with the hammer grab (3) ( See FIG. 1(a)) and
The ground (G) is excavated by the hammer grab (3), and when the rock layer (Gb) included in the ground (G) is reached, the hammer grab (3) is pulled out from the casing (2), and the casing is A step of installing a table machine (4) on top of (2) (see FIG. 1(b));
By inserting a down-the-hole hammer (7A) into the casing (2) and rotating the down-the-hole hammer (7A) by the table machine (4), the rock layer (Gb) is removed by the down-the-hole hammer (7A). a step of excavating to a predetermined depth to form a rock hole (GbAa) (see FIG. 3(a));
After forming the rock hole (GbAa), the down-the-hole hammer (7A) is pulled out from the casing (2), the table machine (4) installed on the upper part of the casing (2) is removed, and the casing is removed. A step of inserting a chisel hammer (9) into (2) to crush the peripheral wall portion (GbAa1) of the rock hole (GbAa) using the chisel hammer (9) (Fig. 3 (b) to (c) ) and
A step of inserting the hammer grab (3) into the casing (2) to recover rock crushing existing in the rock hole (GbAa) using the hammer grab (3) (Fig. 4(a) ), and is characterized by comprising:

Next, the effects of the present invention will be described with reference to the drawings. In addition, although the inside of parenthesis is attached with the reference code|symbol of embodiment mentioned later, this invention is not limited to this.

According to the first aspect of the invention, the casing (2) is press-fitted while being rotated by the all-round rotating device (1), the ground (G) in the casing (2) is excavated by the hammer grab (3), Upon reaching the bedrock layer (Gb) of the ground (G), the hammer grab (3) is pulled out from the casing (2), and the table machine (4) is installed on top of the casing (2). Then, a down-the-hole hammer (7) is inserted into the casing (2), and the down-the-hole hammer (7) is rotated by the table machine (4), so that the bedrock layer (Gb) is moved to a predetermined level by the down-the-hole hammer (7). Drill to depth. After that, the down-the-hole hammer (7) is pulled out from the casing (2), the table machine (4) installed on the upper part of the casing (2) is removed, and the hammer grab (3) is inserted into the casing (2). The hammer grab (3) is used to recover rock crushing generated when excavating the bedrock layer (Gb). As a result, it becomes possible to excavate the ground (G) including the bedrock layer (Gb) by the all-casing construction method using the down-the-hole hammer (7).

Therefore, according to the present invention, compared to the conventional all-casing construction method using only the hammer grab (3), the down-the-hole hammer (7) can be used in combination, shortening the work period for excavating the rock layer (Gb). can do.

According to the second aspect of the invention, the casing (2) is press-fitted while being rotated by the full-circumference rotating device (1), the ground (G) in the casing (2) is excavated by the hammer grab (3), Upon reaching the bedrock layer (Gb) of the ground (G), the hammer grab (3) is pulled out from the casing (2), and the table machine (4) is installed on top of the casing (2). Then, a down-the-hole hammer (7A) is inserted into the casing (2), and the down-the-hole hammer (7A) is rotated by the table machine (4), whereby the bedrock layer (Gb) is moved to a predetermined level by the down-the-hole hammer (7A). Drill to depth to form a rock hole (GbAa). After that, the down-the-hole hammer (7A) is pulled out from the casing (2), the table machine (4) installed on the upper part of the casing (2) is removed, and the chisel hammer (9) is inserted into the casing (2). , the peripheral wall portion (GbAa1) of the rock hole (GbAa) is crushed using the chisel hammer (9). After that, by inserting a hammer grab (3) into the casing (2), the crushed rock in the rock hole (GbAa) is recovered using the hammer grab (3). As a result, it becomes possible to excavate the ground (G) including the bedrock layer (Gb) by the all-casing construction method using both the down-the-hole hammer (7A) and the chisel hammer (9).

Therefore, in the present invention, compared to the conventional all-casing construction method using only the hammer grab (3), the down-the-hole hammer (7A) and the chisel hammer (9) can be used together, so the rock layer (Gb) can be excavated. Work period can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view sequentially showing the ground excavation method according to the first embodiment of the present invention, where (a) shows a state in which a hammer grab is used to excavate to a bedrock layer, and (b) shows the casing. It is a figure which shows the state which is going to install a table machine in the upper part, and (c) shows the state which excavates a bedrock using a down-the-hole hammer. It is a schematic vertical cross-sectional view sequentially showing the ground excavation method according to the embodiment, (a) shows a state in which the down-the-hole hammer is pulled out, and (b) shows a state in which crushed rock is recovered using a hammer grab. , (c) shows a state in which a reinforcing bar basket is inserted into the casing, and (d) shows a state in which pile construction is completed. FIG. 2 is a schematic longitudinal sectional view sequentially showing a ground excavation method according to a second embodiment of the present invention, where (a) shows a state in which rock is being excavated using a down-the-hole hammer, and (b) shows the down-the-hole hammer. (c) shows a state in which the peripheral wall of the rock hole is crushed using a chisel hammer, and (d) is a plan view of the lower surface side of the casing shown in (c). be. FIG. 4 is a schematic vertical cross-sectional view sequentially showing the ground excavation method according to the same embodiment, (a) showing a state in which rock crushing is being recovered using a hammer grab, and (b) showing a reinforcing bar cage in the casing. It shows the inserted state, and (c) shows the state where pile construction is completed.

<Description of the first embodiment>
A first embodiment of the ground excavation method according to the present invention will be specifically described below with reference to FIGS. 1 and 2. FIG. In the following description, when the directions of up, down, left, and right are indicated, they refer to up, down, left, and right when viewed from the front of the drawing.

As shown in FIG. 1, when excavating a ground G comprising a shallow layer Ga consisting of a sand layer, a mud layer, a boulder layer, a gravel layer, etc. and a bedrock layer Gb on the deep side, first, as shown in FIG. As shown in FIG. 2, a full-circumference rotating device 1 having a conventionally known structure is installed on the ground G. As shown in FIG. Then, the outer peripheral surface of a substantially cylindrical casing 2 elongated in the axial direction (vertical longitudinal direction) shown in FIG. is pressed into the ground G as shown in FIG. 1(a). At this time, as shown in FIG. 1(a), a hammer glove 3 is inserted into the casing 2 to excavate the ground G (shallow layer Ga) within the casing 2. As shown in FIG. The hammer grab 3 is suspended by a crawler crane M having a boom B shown in FIG. More specifically, as shown in FIG. 1(a), the crawler crane M has a hoisting rope R hung around a sheave S provided at the tip of a boom B, and a hook F connected to the tip of the hoisting rope R. By doing so, it is considered as a working posture. A suspension wire W connected to a hook F of the crawler crane M holds the crown K at a predetermined height. , is suspended.

Thus, the ground G (shallow layer Ga) inside the casing 2 is excavated by the hammer grab 3 until it reaches the bedrock layer Gb, as shown in FIG. 1(a).

Next, when the bedrock layer Gb is reached, the hammer glove 3 is pulled out from the casing 2, and the table machine 4 is attached and fixed to the upper part of the casing 2 as shown in FIG. 1(b). More specifically, as shown in FIG. 1(b), a hollow cylindrical female joint portion 2a is provided in the upper portion of the casing 2, and a hollow cylindrical female joint portion 2a corresponds to the female joint portion 2a. A male joint 4a is provided at the bottom of the table machine 4. As shown in FIG. As a result, the table machine 4 can be attached and fixed to the upper portion of the casing 2 by fitting the male joint portion 4a into the female joint portion 2a. In addition, the male type joint part 4a also plays a role of a reaction force mount for the table machine 4. As shown in FIG.

Next, as shown in FIG. 1(c), a rod 5 elongated in the axial direction (vertical longitudinal direction) is inserted into an annular driving member (not shown) of the table machine 4. As shown in FIG. As a result, the protruded streak portion 5a provided on the outer peripheral surface of the rod 5 is engaged with the recessed streak portion (not shown) of the driving annular member (not shown). 1(c), a swivel mechanism 6 is connected to the upper portion 5b of the rod 5 using a connecting pin or the like (not shown). It is suspended by a support wire W. Further, a down-the-hole hammer 7 with a large diameter (for example, 1000 mm, 1200 mm, 1500 mm) is provided on the lower portion 5c of the rod 5. As shown in FIG.

Thus, as shown in FIG. 1(c), the down-the-hole hammer 7 is inserted into the casing 2, the rod 5 is inserted into the driving annular member (not shown) of the table machine 4, and the upper portion of the down-the-hole hammer 7 is inserted. If the lower part 5c of the rod 5 is attached to 7a, the state shown in FIG. 1(c) is obtained. In this state, the down-the-hole hammer 7 is vertically moved by the pressure air of the swivel mechanism 6 to apply a striking force to the rock layer Gb. 5 will also rotate, and thus the down-the-hole hammer 7 will also rotate. Thus, by the striking force and rotational force of the down-the-hole hammer 7, the rock layer Gb can be excavated to a predetermined depth as shown in FIG. 1(c).

Next, after excavating the bedrock layer Gb to a predetermined depth using the down-the-hole hammer 7, the down-the-hole hammer 7 and the rod 5 are pulled out from the casing 2 as shown in FIG. 2(a). In addition, as shown in FIG. 2A, a rock hole Gba is formed in the rock layer Gb by excavating to a predetermined depth using the down-the-hole hammer 7 .

Next, as shown in FIG. 2(b), the table machine 4 attached and fixed to the upper part of the casing 2 is removed, and the casing 2 is pressed into the rock hole Gba while being rotated all around by the all-around rotating device 1. . At this time, a hammer glove 3 is inserted into the casing 2 and used to recover rock crushing generated when the rock layer Gb is excavated. As shown in FIG. 2(b), the hammer grab 3 is suspended by the same method as that shown in FIG. ing.

Next, as shown in FIG. 2(c), a reinforcing bar cage 8 is inserted into the casing 2, and concrete CO (see FIG. 2(d)) is cast. Then, after concrete CO (see FIG. 2(d)) is placed, the casing 2 is pulled out from the ground G, and the all-round rotating device 1 is removed from the ground G. As a result, pile construction is completed as shown in FIG. 2(d).

Thus, in this way, the ground G can be excavated and piles can be constructed.

Thus, according to the present embodiment described above, the casing 2 is press-fitted while being rotated by the all-around rotating device 1, the ground G in the casing 2 is excavated by the hammer grab 3, and the bedrock layer of the ground G is excavated. When reaching Gb, the hammer glove 3 is pulled out from inside the casing 2, and the table machine 4 is installed on the upper part of the casing 2. - 特許庁A down-the-hole hammer 7 is inserted into the casing 2 and rotated by the table machine 4 to excavate the bedrock layer Gb to a predetermined depth. After that, the down-the-hole hammer 7 is pulled out from the casing 2, the table machine 4 installed on the upper part of the casing 2 is removed, and the hammer grab 3 is inserted into the casing 2 to remove the rock generated when excavating the rock layer Gb. Cracks are collected using a hammer grab 3. This makes it possible to excavate the ground G including the rock layer Gb by the all-casing construction method using the down-the-hole hammer 7 together.

Thus, according to the present embodiment, the down-the-hole hammer 7 can be used in combination as compared with the conventional all-casing construction method using only the hammer grab 3, so the work period for excavating the rock layer Gb can be shortened.

<Description of Second Embodiment>
Next, a second embodiment of the ground excavation method according to the present invention will be specifically described with reference to FIGS. 3 and 4. FIG. The same reference numerals are given to the same members as in the first embodiment, and detailed description thereof will be omitted.

Since the ground excavation method according to the second embodiment is the same up to FIGS.

Next, as shown in FIG. 3(a), a rod 5A elongated in the axial direction (vertical longitudinal direction) is inserted into the drive ring member (not shown) of the table machine 4. As shown in FIG. As a result, the protruding portion 5Aa provided on the outer peripheral surface of the rod 5A is engaged with the recessed portion (not shown) of the driving annular member (not shown). 3(a), a swivel mechanism 6 is connected to the upper portion 5Ab of the rod 5A using a connecting pin or the like (not shown). It is suspended by a support wire W. Further, a down-the-hole hammer 7A having substantially the same diameter as the inner diameter of the rod 5A is provided on the lower portion 5Ac of the rod 5A.

Thus, by inserting the rod 5A provided with the down-the-hole hammer 7A into the drive annular member (not shown) of the table machine 4 and into the casing 2, as shown in FIG. state. In this state, the down-the-hole hammer 7A is moved up and down by the pressure air of the swivel mechanism 6 to apply a striking force to the rock layer Gb. 5A will also rotate, and therefore the down-the-hole hammer 7A will also rotate. Thus, by the striking force and rotational force of the down-the-hole hammer 7A, the rock layer Gb can be excavated to a predetermined depth as shown in FIG. 3(a).

Next, after excavating the rock layer Gb to a predetermined depth using the down-the-hole hammer 7A, the down-the-hole hammer 7A and the rod 5A are pulled out of the casing 2 as shown in FIG. 3(b). In addition, as shown in FIG. 3B, a rock hole GbAa is formed in the rock layer Gb by excavating to a predetermined depth using the down-the-hole hammer 7A.

By the way, the rock hole GbAa has a diameter smaller than that of the casing 2, as shown in FIGS. 3(b) and 3(d). Therefore, it is difficult to press-fit the casing 2 into the rock hole GbAa.

Therefore, in this embodiment, as shown in FIG. 3(c), the table machine 4 attached and fixed to the upper part of the casing 2 is removed, the chisel hammer 9 is inserted into the casing 2, and is aimed at the rock hole GbAa. let it drop. As a result, the peripheral wall portion GbAa1 of the rock hole GbAa is crushed. That is, as shown in FIG. 3(d), a circular rock hole GbAa is bored in the center of the rock layer Gb located on the lower surface of the casing 2 to form a free surface. As shown in FIG. 3(c), when 9 falls toward the rock hole GbAa, the peripheral wall portion GbAa1 of the rock hole GbAa is easily crushed.

Next, after crushing the peripheral wall portion GbAa1 of the rock hole GbAa, the chisel hammer 9 is pulled out from the casing 2, and as shown in FIG. It is press-fitted into the rock hole GbAa. At this time, a hammer glove 3 is inserted into the casing 2 to collect rock crushed when the rock layer Gb is excavated and the peripheral wall GbAa1 of the rock hole GbAa is crushed. The hammer grab 3 is suspended by the same method as shown in FIG. 2(b).

Next, as shown in FIG. 4(b), a reinforcing bar cage 8 is inserted into the casing 2, and concrete CO (see FIG. 4(c)) is cast. After the concrete CO (see FIG. 4(c)) is placed, the casing 2 is pulled out from the ground G, and the all-round rotating device 1 is removed from the ground G. As a result, pile construction is completed as shown in FIG. 4(c).

Thus, even if the down-the-hole hammer 7A does not have a large diameter like the down-the-hole hammer 7 shown in the first embodiment, it can excavate the ground G and form piles.

Thus, according to the present embodiment described above, the casing 2 is press-fitted while being rotated by the all-around rotating device 1, the ground G in the casing 2 is excavated by the hammer grab 3, and the bedrock layer of the ground G is excavated. When reaching Gb, the hammer glove 3 is pulled out from inside the casing 2, and the table machine 4 is installed on the upper part of the casing 2. - 特許庁By inserting the down-the-hole hammer 7A into the casing 2 and rotating the down-the-hole hammer 7A by the table machine 4, the rock layer Gb is excavated to a predetermined depth by the down-the-hole hammer 7A to form a rock hole GbAa. After that, the down-the-hole hammer 7A is pulled out from inside the casing 2, the table machine 4 installed on the upper part of the casing 2 is removed, and the chisel hammer 9 is inserted into the casing 2, whereby the peripheral wall portion GbAa1 of the rock hole GbAa is cut by the chisel hammer 9. Crush using After that, by inserting the hammer grab 3 into the casing 2 , the crushed rock in the rock hole GbAa is recovered using the hammer grab 3 . As a result, it becomes possible to excavate the ground G including the rock layer Gb by the all-casing construction method that uses the down-the-hole hammer 7A and the chisel hammer 9 together.

Therefore, in the present embodiment as well, compared to the conventional all-casing construction method using only the hammer grab 3, the down-the-hole hammer 7A and the chisel hammer 9 can be used together, so the work period for excavating the rock layer Gb can be shortened. can.

The ground excavation method shown in this embodiment is merely an example, and various modifications and changes are possible within the scope of the present invention described in the claims. For example, in the first embodiment, after the rock hole Gba is formed, the casing 2 is pressed into the rock hole Gba. , the casing 2 may be press-fitted.

In the second embodiment, the casing 2 is press-fitted after the peripheral wall portion GbAa1 of the rock hole GbAa is crushed. may be press-fitted.

1 Circumference Rotating Device 2 Casing 3 Hammer Grab 4 Table Machines 7, 7A Down-the-hole Hammer 9 Chisel Hammer G Ground Gb Rock Layer GbAa Rock Hole GbAa1 Surrounding Wall

According to the first aspect of the invention, the step ( See FIG. 1(a)) and
When the ground (G) is excavated by the hammer grab (3) and the bedrock layer (Gb) included in the ground (G) is reached, the casing (2 ), the hammer grab (3) is pulled out from inside the casing (2), and is provided at the bottom of the table machine (4) corresponding to the first joint (female joint 2a) provided at the top of the casing (2). A step of installing the table machine (4) on the top of the casing (2) by fitting the second joint portion (male joint portion 4a) to the first joint portion (female joint portion 2a) (Fig. 1(b)) and
By inserting a down-the-hole hammer (7) into the casing (2) and rotating the down-the-hole hammer (7) by the table machine (4 ) instead of the rotating device (1) , the rock layer ( Gb) to a predetermined depth with the down-the-hole hammer (7) (see FIG. 1(c));
After excavating the rock layer (Gb) to the predetermined depth, the down-the-hole hammer (7) is pulled out from within the casing (2), and the table machine (4) installed on top of the casing (2) is removed. Removing and inserting the hammer grab (3) into the casing (2) to recover rock crushing generated when excavating the rock layer (Gb) using the hammer grab (3) ( (see FIGS. 2(a) and 2(b)).

According to the second aspect of the invention, the step of press-fitting the casing (2) while rotating it by the full-circumference rotating device (1) and excavating the ground (G) in the casing (2) with the hammer grab (3) ( See FIG. 1(a)) and
When the ground (G) is excavated by the hammer grab (3) and the bedrock layer (Gb) included in the ground (G) is reached, the casing (2 ), the hammer grab (3) is pulled out from inside the casing (2), and is provided at the bottom of the table machine (4) corresponding to the first joint (female joint 2a) provided at the top of the casing (2). A step of installing the table machine (4) on the top of the casing (2) by fitting the second joint portion (male joint portion 4a) to the first joint portion (female joint portion 2a) (Fig. 1(b)) and
By inserting a down-the-hole hammer (7A) into the casing (2) and rotating the down-the-hole hammer (7A) by the table machine ( 4) instead of the rotating device (1) , the rock layer ( Gb) to a predetermined depth with the down-the-hole hammer (7A) to form a rock hole (GbAa) (see FIG. 3(a));
After forming the rock hole (GbAa), the down-the-hole hammer (7A) is pulled out from the casing (2), the table machine (4) installed on the upper part of the casing (2) is removed, and the casing is removed. A step of inserting a chisel hammer (9) into (2) to crush the peripheral wall portion (GbAa1) of the rock hole (GbAa) using the chisel hammer (9) (Fig. 3 (b) to (c) ) and
A step of inserting the hammer grab (3) into the casing (2) to recover rock crushing existing in the rock hole (GbAa) using the hammer grab (3) (Fig. 4(a) ), and is characterized by comprising:

According to the first aspect of the invention, the casing (2) is press-fitted while being rotated by the all-round rotating device (1), the ground (G) in the casing (2) is excavated by the hammer grab (3), When the rock layer (Gb) provided by the ground (G) is reached , the hammer grab (3) is pulled out from inside the casing (2) while the installation of the all-around rotating device (1) is left as it is, and it is placed on the upper part of the casing (2). The second joint portion (male joint portion 4a) provided at the bottom of the table machine (4) corresponding to the provided first joint portion (female joint portion 2a) is connected to the first joint portion (female joint portion A table machine (4) is installed on top of the casing (2) by fitting it into the part 2a) . Then, by inserting a down-the-hole hammer (7) into the casing (2) and rotating the down-the-hole hammer (7) by the table machine (4 ) instead of the rotating device (1) , the bedrock layer (Gb) is removed. is excavated to a predetermined depth by the down-the-hole hammer (7). After that, the down-the-hole hammer (7) is pulled out from the casing (2), the table machine (4) installed on the upper part of the casing (2) is removed, and the hammer grab (3) is inserted into the casing (2). The hammer grab (3) is used to recover rock crushing generated when excavating the bedrock layer (Gb). As a result, it becomes possible to excavate the ground (G) including the bedrock layer (Gb) by the all-casing construction method using the down-the-hole hammer (7).

According to the second aspect of the invention, the casing (2) is press-fitted while being rotated by the full-circumference rotating device (1), the ground (G) in the casing (2) is excavated by the hammer grab (3), When the rock layer (Gb) provided by the ground (G) is reached , the hammer grab (3) is pulled out from inside the casing (2) while the installation of the all-around rotating device (1) is left as it is, and it is placed on the upper part of the casing (2). The second joint portion (male joint portion 4a) provided at the bottom of the table machine (4) corresponding to the provided first joint portion (female joint portion 2a) is connected to the first joint portion (female joint portion A table machine (4) is installed on top of the casing (2) by fitting it into the part 2a) . Then, by inserting a down-the-hole hammer (7A) into the casing (2) and rotating the down-the-hole hammer (7A) by the table machine (4 ) instead of the rotating device (1) , the bedrock layer (Gb) is removed. is excavated to a predetermined depth by the down-the-hole hammer (7A) to form a rock hole (GbAa). After that, the down-the-hole hammer (7A) is pulled out from the casing (2), the table machine (4) installed on the upper part of the casing (2) is removed, and the chisel hammer (9) is inserted into the casing (2). , the peripheral wall portion (GbAa1) of the rock hole (GbAa) is crushed using the chisel hammer (9). After that, by inserting a hammer grab (3) into the casing (2), the crushed rock in the rock hole (GbAa) is recovered using the hammer grab (3). As a result, it becomes possible to excavate the ground (G) including the bedrock layer (Gb) by the all-casing construction method using both the down-the-hole hammer (7A) and the chisel hammer (9).

Claims (2)

a step of press-fitting the casing while rotating it with a full-circumference rotating device, and excavating the ground in the casing with a hammer grab;
a step of excavating the ground with the hammer grab and, when reaching a bedrock layer included in the ground, withdrawing the hammer grab from within the casing and installing a table machine on top of the casing;
a step of inserting a down-the-hole hammer into the casing and rotating the down-the-hole hammer by the table machine to excavate the bedrock layer to a predetermined depth with the down-the-hole hammer;
After excavating the rock layer to the predetermined depth, the down-the-hole hammer is pulled out from within the casing, the table machine installed at the top of the casing is removed, and the hammer grab is inserted into the casing, A ground excavation method comprising the step of recovering rock crushing generated when excavating the rock layer using the hammer grab. a step of press-fitting the casing while rotating it with a full-circumference rotating device, and excavating the ground in the casing with a hammer grab;
a step of excavating the ground with the hammer grab and, when reaching a bedrock layer included in the ground, withdrawing the hammer grab from within the casing and installing a table machine on top of the casing;
a step of inserting a down-the-hole hammer into the casing and rotating the down-the-hole hammer by the table machine to excavate the bedrock layer to a predetermined depth with the down-the-hole hammer to form a bedrock hole;
After forming the rock hole, the down-the-hole hammer is pulled out from the casing, the table machine installed on the upper part of the casing is removed, and a chisel hammer is inserted into the casing to form the peripheral wall portion of the rock hole. A step of crushing using the chisel hammer;
a ground excavation method comprising a step of inserting the hammer grab into the casing to recover rock crushed material existing in the rock hole using the hammer grab.

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