JP2003328386A - Boring device and underground borehole drilling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boring device and its method enabling the drilling of a borehole in an underground in an economical and highly direction-stable manner. <P>SOLUTION: The borehole is formed by the rotating drive and simultaneous sinking operation of at least three collocated boring strings 7a, 7b, 7c. The boring strings contains cutting devices 10a, 10b, 10c for underground cutting operation. The end of the central boring string 7c on its ground side is offset from the outside boring string. The boring strings are connected to one another with a yoke 20 and mounted to be rotatable in the yoke. The yoke 20 has an angle displacement part 22 angled to the offset direction, near the offset central boring string. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a boring device,
And a method for excavating a boring hole.

[0002]

It is known in underground engineering to construct a shroud or foundation element in the ground by excavating parallel bores into the ground to form a slot-like boring chamber. This chamber is typically filled with a fully hardenable or solidifiable suspending material at the same time the borehole is drilled down. The suspension material is mixed with at least a portion of the ground soil material, which in the hardened state forms an enclosure wall or foundation element in the ground.

German Patent No. 693 31 552 T2
U.S. Pat. No. 4,909,675 discloses a conventional boring device. The device comprises at least three juxtaposed rotatable boring strings,
At least one yoke, each boring string including a cutting device at a ground-side end. The ground-side end of the central boring string is offset with respect to the outer boring string.
The boring strings are rotatably mounted in the yoke and connected to each other. In such a boring device, the juxtaposed boring strings can be rotationally driven and simultaneously drilled, which makes it possible to construct the bore wall particularly economically.

Building a continuous bore wall typically requires overlapping the boring radii of adjacent boring strings. The cutting devices of each boring string must be axially offset from each other to avoid collision of the individual cutting devices of the boring string. Especially when the boring depth is deep, it is necessary to connect and fix the lower parts of the individual boring strings. It is usually implemented by so-called yokes, which are beam-shaped members. In the yoke, the boring strings are rotatably mounted and connected to each other.
It is further envisaged that the yoke may also have the function of shearing the ridges of soil material remaining between adjacent boring holes, thereby cooperating in the grinding of soil material.

The area of the boring string between the bit and the yoke is used for soil pretreatment, ie for grinding the soil material and supplying the suspension material. In the grinding of soil material, not only the cutting device itself provided at the tip of the boring string for soil breaking and shearing, but also the feed spiral adjacent to it plays an important role. The feed spiral exerts a considerable shearing force on the soil material and thus a grinding action. In addition, a curable suspension material is provided in the area below the yoke.

A stirring member is provided in a region above the yoke. The stirring member thoroughly stirs and homogenizes the solidifiable suspension material and the ground soil material.

In order to build a high quality bore wall, it is critically important that the soil material be ground very uniformly by the pretreatment area of the boring unit. In the pretreatment areas of all three boring strings, sufficient space between the axially offset individual bits and the yoke must be provided to ensure a very uniform grinding of the soil material. is there. However, for good rigidity and the resulting improved drilling, it is advantageous to have the fixed yoke as close to the bit as possible.

Another device and method for boring hole construction is known from DE 42 19150 C1. In this known method, an auger is screwed into the soil in a spiral. By stopping the progress of the auger at a predetermined depth and continuing the rotation drive, the soil is sheared and ground. The ground soil material is moved along the auger to the upper region within the borehole. At the same time, by supplying the coagulable suspension material, the coagulable suspension material and the ground soil material are stirred together. By this stirring action, a cylindrical jacket-shaped filter cake is formed around the wall of the borehole. This provides a cylindrical support jacket, which improves the strength and carrying capacity characteristics of the formed base stanchions.

[0009]

[Patent Document 1] German Patent No. 69331552T2

[Patent Document 2] US Pat. No. 4,909,675

[Patent Document 3] German Patent Invention No. 4219150

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a boring device and method which makes it possible to dig a boring hole in the ground particularly economically and with high directional stability.

[0011]

SUMMARY OF THE INVENTION The above objects are achieved by a device having the features of claim 1 and a method having the features of claim 7.

The boring device according to the invention is characterized in that the yoke has an angular displacement in the vicinity of the offset central boring string, which is angled towards its offset direction. Therefore, the yoke is configured to have an angular displacement that corresponds to the offset of the central boring string rather than as a straight beam. This allows the yoke to be placed relatively close to the bit,
The boring strings can be fixed well in common near the cutting device where maximum torque acts on the individual boring strings. At the same time, despite the axial offset of the boring strings relative to each other, sufficient space is provided in the offset areas of the boring strings as a pretreatment area necessary for optimum uniform grinding of the soil material. Compared to the conventional straight beam yoke, the angular displacement according to the present embodiment completely or at least partially corrects the difference in length of the boring string in the pretreatment area. In this way, in spite of the axial offset of the individual boring strings, the distance from the bit to the yoke can be equal or at least approximately equal.

A more uniform operating length of the boring string in the pretreatment area below the yoke results in a uniform torque load and tool wear of the individual boring strings, which has a positive effect on maintenance costs.

The arrangement according to the invention can also be used in boring devices having four, five or more boring strings. In that case, the central boring string or strings may be offset axially longer or shorter than the outer boring string.

According to the present invention, it is also preferable that the boring radii of the cutting devices of the adjacent boring strings overlap. The spacing of the central axes of the individual boring strings is smaller than the boring hole diameter of the cutting device. The greater the degree of overlap, the flatter the wall thickness pattern of the borehole. However, even if the boring radii do not overlap at all or only slightly, it is possible to ensure a very constant bore wall width by providing the tool bit or cutting plate on the yoke.

In order to construct the bore wall or the base element particularly economically, according to the invention, the supply of a completely hardenable or solidifiable suspension material can be carried out through at least one boring string. It is suitable. The supply of suspension material is preferably carried out through a central boring string which is installed particularly backwards compared to other boring strings. The supply is carried out by a pumping mechanism using a tubular boring string whose outlet is located at or near the bit.

According to the present invention, it is more preferable to provide a stirring member above the yoke along the boring string to form a stirring region. The agitating member may be an agitating or feed paddle that projects substantially radially from the boring string. These components mix the introduced suspension material with a portion of the ground soil material and substantially homogenize it.

According to the invention, for good grinding of the soil material, a feed spiral leading to the cutting device is provided on the boring string, forming a pretreatment area below the yoke. The worm-like feed spiral moves the ground soil material away from the cutting device while at the same time further grinding the cut material. At the same time, by supplying the suspension material, initial mixing, that is, pretreatment for mixing the soil material and the suspension material is performed.

The feed spiral can be of random length and can include segments having different pitches and diameters. According to the present invention, the feed spiral has a pitch of 1 pitch or less, whereby a particularly compact structure is obtained.
A feed spiral of 0.5 to 1 pitch provides a reliable transfer of soil material and a favorable additional grinding effect.

The method according to the invention is characterized in that the pretreatment areas below the yokes in the individual boring strings are at least partially compensated for each other by the angular displacements of the yokes along the offset direction of the central boring string. . Thereby, a particularly uniform grinding of the soil material can be carried out, which is of decisive advantage in the construction of the bore wall. At the same time, the yoke can be placed very close to the bit, so that a good fixation is obtained and a high directional stability can be achieved in drilling a boring hole.

According to the invention, the borehole formed by the boring string can be provided with an overlap in order to construct a bore wall of very uniform width.

Further, according to the present invention, the soil material is crushed in the pretreatment region below the yoke and the stirring region above the yoke, and the crushed soil material is stirred with the supplied suspension material by using the stirring member. it can. The yoke divides the lower pretreatment zone, which plays a crucial role in the grinding of the soil material, and the stirring zone, in which the material mixture is produced and homogenized.

In order to correct the torque behavior of the boring device, it is possible according to the invention to drive the two outer boring strings in opposite rotational directions. In the present invention, in order to construct a very homogeneous bore wall mass,
It is preferred to feed the suspension through the central boring string.

According to the present invention, sand or other material is blown into the boring hole as the boring string is pulled up. The material can be a particulate material or other material that increases strut strength, which is not desirable to feed during the stirring process and during the formation of the special lining of the borehole wall. Blowing can be carried out through one of the boring strings, in particular the boring string used to supply the suspension material.

In the method according to the invention, drilling with a boring string can be carried out at a constant speed. In order to improve the consistency of the solidifiable suspending material forming the base element, according to the invention, it is possible to raise the boring string at predetermined time intervals and then lower it again for the purpose of stirring. It is suitable. However, during the digging, since the ground soil material is already agitated by the particular configuration of the boring device according to the invention, the digging can be carried out constantly and continuously.

[0026]

The invention and the advantages achieved thereby are explained in more detail below in connection with preferred embodiments and the accompanying schematic drawings.

1 and 2 show a boring implement 1 for constructing mortar columns. In addition, FIG.
It is a figure which shows the state which looked at the ball string and the member relevant to this from the right side. The upright derrick 2 which can be swung in two planes including the vertical axis is provided with a boring device 3
Is attached. On the slide 4 movable along the derrick 2, the three rotary drives 5 (5a, 5b, 5)
c) is arranged, and each driving machine has a driving mechanism 6 (6a, 6a).
b, 6c). Three rotary drive machines 5a, 5b, 5
c is fixed to a common slide 4 and can move along the derrick 2 only as a unit.

Each driving mechanism 6a, 6b, 6c is provided with a boring string 7 (7a, 7b, 7c). Each boring string 7a, 7b, 7c is a substantially tubular member, and has a bit 9 (9a, 9b, 9c) at the lower end facing the borehole 8 and a cutting device 10 (10a, 10a, 10b, 10c). The cutting devices 10a, 10b, 10c have feed spirals 11 (11a, 11a,
11b, 11c) are connected. Feed spiral 11a, 1 of two boring strings 7a, 7b
1b almost completely overlaps the central boring string 7c in the tip region. The two outer boring strings 7a, 7b have a spiral with a small outer diameter in a position horizontal to the feed spiral 11c of the central boring string 7c, whereby the cutting device 10 is provided.
The material obtained by boring is moved from the cutting areas a and 10b. Two outer bowling strings 7
Since a and 7b rotate in opposite directions, the feed spirals 11a and 11b also have opposite rotation directions.

A guide 13 common to the three boring strings 7 is provided above the feed spirals 11a, 11b, 11c of the three boring strings 7. Above the common guide 13, paddles or stirring members 14 are attached to the boring strings 7a, 7b, 7c to thoroughly stir the material obtained by boring. Each of these stirring members 14
The protrusions are provided at different heights so that the operation areas overlap. In addition, the paddle or stirring member 14 is arranged at a predetermined angle with respect to the horizontal plane in order to expand the operation area. This allows the walls to be formed by overlapping mortar struts.

Since the length of the stirring area of the boring strings 7a, 7b, 7c occupies a small proportion to the total length of the boring string, sufficient torque can be applied for thorough stirring of the soil. Above the paddle structure is another common guide 15 for the three boring strings. The guide 15 is movable, and the boring strings 7a, 7b, 7c.
Attached to and can move along the remaining range of the three strings. The displaceable guide 15 has a funnel-shaped projection 16 which engages the boring string in the funnel-shaped accommodating portion 17 when performing boring and is firmly fixed to the lower end of the derrick 2. Therefore, during the boring process, the three boring strings are guided and do not deviate from the intended boring direction.

The suspension material is the central boring string 7c.
Or all three bowling strings 7a, 7
b, 7c. Bits 9a, 9b, 9c
Suspension material is supplied to the material obtained by boring in the vicinity. The suspension material delivery port is located in the lower region of the central boring string 7c. All outlets
It is protected from being blocked by the material obtained by the boring during the boring operation and is located in an area where it can be avoided.

In the enlarged detail view of FIG. 3, the central boring string 7c is replaced by two outer boring strings 7a, 7a.
The configuration in which it is displaced with respect to b is shown in more detail.
All three boring strings 7 have a cutting device 10 of identical construction and a feed spiral 11 of approximately 1 pitch connected to it, at the ground-side end. In order to overlap the boring radii, the central boring string 7c is arranged backward by about one pitch of the feed spiral 11. At the same height as the feed spiral 11c of the central boring string 7c, the smaller diameter feed spiral 18 (18) is provided on the two outer boring strings 7a, 7b.
a, 18b) are provided so that the individual boring strings 7 can be rotationally driven without collision.

In order to fix the arrangement of the three boring strings 7, a high-rigidity beam-shaped yoke 20 is provided near the end of the boring string on the side exposed to the cutting force. The yoke has a bearing area 26 for each of the three boring strings 7. At the bearing area 26, each boring string is rotatably and fixedly supported along its axis. Central bowling string 7c
Despite the rearward arrangement, the present embodiment ensures a sufficient space for the feed spiral 11c. In the present embodiment, the angular displacement portion 22 is provided in the central area of the yoke 20. The angular displacement portion 22 is composed of two ridge portions arranged at an angle, and has two outer bearing regions 26.
And the central bearing region 26. Thereby, the working area of the boring string 7 below the yoke 20, which constitutes a so-called pretreatment area, is at least partially supplemented. The pretreatment zone plays a very important role in the cutting and grinding of the soil and in the initial thorough stirring of the ground soil material and the suspension material. As a result of the provision of the angular displacement portion 22 of the present embodiment on the yoke 20, the pretreatment of the ground soil in the pretreatment area can be performed substantially uniformly on all three boring strings 7. A uniform pretreatment is advantageous in forming a uniform, high quality foundation post or wall. The present invention also produces more uniform torque loading and tool wear in all three boring strings.

The angular displacement portion 22 of the yoke 20 has four points with respect to the boring string axis in accordance with the angular displacement.
An edge 24 forming a 5 ° angle is formed. This angled edge configuration is useful for shearing ridges of soil material that remain between juxtaposed boring holes. The angled edges 24 facilitate shearing of the remaining soil material ridges, thereby facilitating drilling of the boring device.

Above the yoke 20, a stirring region, only a part of which is shown, is connected. The stirring area has a paddle-shaped stirring member provided on the boring string 7. In order to compensate for the angular displacement 22 of the yoke 20, the two outer boring strings 7a, 7b are respectively provided with
Adjacent to the yoke 20, additional feed spirals 19a, 19b of about 1 pitch are provided. It is also possible to construct the lower part of the boring device, including the yoke 20 and the lower ends of the individual boring strings 7, as separate parts. The separate parts in that case are axially engaged on the boring string 7 and connected for rotation therewith via a shaft-hub connection 28 shown schematically.

The present invention is directed to, for example, mortar stanchions.
The present invention relates to a method of constructing a pile wall by overlapping boring. First, a trench to be excavated is formed in advance. Boring to a predetermined depth with the device according to the invention. Bowling
The feed spirals 11a, 11b, 11c and the boring strings 7a, 7b provided with the stirring member 14,
Oriented roughly along the longitudinal direction with the 7c portion. Boring is carried out without soil transportation. At the same time or after that, the suspension material is supplied to the tips of the three boring strings, or only to the tips of the central boring string 7c, and the strings 7a, 7
The boring device 3 is pulled up while rotating b and 7c. Then, the boring is performed again to the predetermined depth. The suspension material is a self-coagulating water-binder mixture. By repeating the above steps several times, the soil is surely liquefied by the suspension material. The suspension material is added in an amount just to accommodate the pore volume of the soil. Until suspension material flows in the pre-drill (until suspension passes
out), continue the stirring process. The above steps are repeated in the next depth region until the desired final depth is reached. Thereby, a continuous boring and stirring process is carried out. When pulling up the boring tool, it is also possible to blow sand or other material to improve the specific strength of the foundation columns.

[Brief description of drawings]

FIG. 1 is a schematic partial front view showing a boring device according to the present invention.

FIG. 2 is a side view showing the boring device according to the present invention including a related carrying device.

FIG. 3 is an enlarged detail view of a boring apparatus including an angle-displaced yoke according to the present invention.

[Explanation of symbols]

7 boring string, 7a, 7b outer boring string, 7c central boring string, 9 bit, 10 cutting device, 11 feed spiral, 14 stirring member, 20 yoke, 22 angular displacement part.

Claims (13)

[Claims] 1. At least three side-by-side rotationally drivable boring strings (7), wherein a cutting device (1) is provided at the ground-side end of each boring string (7).
0) and the ground side end of the central boring string (7c) is offset with respect to the outer boring string (7a, 7b) and the boring string (7) is rotatable. At least one yoke (2
0), and the yoke (20) has an angular displacement portion (22) angled toward the offset direction in the vicinity of the offset central boring string (7c). Boring equipment characterized by. 2. Boring device according to claim 1, characterized in that the boring radii of the cutting devices (10) of adjacent boring strings (7) overlap. 3. Boring device according to claim 1, characterized in that the solidifiable suspending material is fed to at least one boring string (7). 4. Boring device according to claim 1, characterized in that the stirring member (14) constituting the stirring region is arranged above the yoke (20) along the boring string (7). And a boring device. 5. Boring device according to claim 1, wherein a feed spiral (11) leading to the cutting device (10) is provided on the boring string (7), so that it is below the yoke (20). A boring machine, characterized in that a pretreatment area is formed. 6. Boring device according to claim 5, characterized in that the feed spiral (11) has a pitch of less than or equal to 1 pitch. 7. A method of constructing a boring hole in the ground by rotationally driving and simultaneously excavating at least three juxtaposed boring strings (7), each boring string (7) being cut at a ground-side end. Device (1
0), the ground side end of the central boring string (7c) is offset from the outer boring string (7a, 7b), and the boring strings (7) are connected to each other by at least one yoke (20). , The bowling string (7) is the yoke (2
In the method, which is mounted rotatably in 0), the pretreatment area provided below the yoke (20) along the individual boring string (7) is oriented in the offset direction of the central boring string (7c). Characterized in that they are at least partially complementary to each other by a deformed portion (22) of the yoke (20) angled with
Method. 8. A method according to claim 7, characterized in that the boring holes produced by the boring string (7) overlap. 9. The method according to claim 7, wherein the soil material is ground in a pretreatment area below the yoke (20) and the ground material is fed in a stirring area above the yoke (20). The suspension material is stirred with a stirring member (14). 10. Method according to claim 7, characterized in that the two outer boring strings (7a, 7b) are driven in opposite rotational directions. 11. A method according to claim 7, characterized in that the suspension material is fed through a central boring string (7c). 12. A method according to claim 7, characterized in that, for the purpose of stirring, the boring string (7) is raised at predetermined time intervals and then lowered again. 13. A method according to claim 7, characterized in that sand or other material is blown into the boring hole when pulling up the boring string (7).