JPH0423991Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to the improvement of boring equipment, and more specifically, the invention is concerned with the improvement of boring equipment. By completely blocking the hole, the purpose is to prevent various failures such as collapse of the hole bottom and hole wall, and to improve work efficiency.

(Prior Art) Various boring devices for digging underground have been developed so far. It basically consists of a core tube with a built-in boring rod for drilling, and a metal crown with the core tube attached to the tip.Drilling is done by rotating the core tube while pumping boring water through the boring rod. It's starting to work.

(Problems to be solved by the invention) However, when performing excavation work using the above-mentioned conventional boring equipment, not only does the excavation debris left in the hole become an obstacle to the work, but also When the boring rod was removed at the section, due to the difference in specific gravity between the fresh water (muddy water) inside the boring rod and the wastewater (clean water or muddy water mixed with slime), fresh water (muddy water) was released from the cut part of the rod.
flows backwards and blows up. This backflow not only worsens the working environment and causes various negative effects, but also increases the flow rate of fresh water (muddy water) at the bottom of the hole and its side walls, causing collapse of the bottom or wall of the hole, resulting in a reduction in boiling. It will provoke.

(Means for Solving the Problems) The present invention solves the problems in the prior art described above, stops the pumping of boring water, and completely eliminates the blow-up caused by backflow when the boring rod is removed from the ground. By blocking the hole, it is possible to prevent various obstacles such as collapse of the hole bottom and hole wall, and to improve work efficiency. A core tube having a coarse-end slime collection section having a shape of 1.0 mm, a cylindrical narrow-end slime collection section connected to the coarse slime collection section via a coupling ring, and a boring rod whose tip is inserted into the core tube. In the coarse slime collection section, a plurality of rod-shaped elastic bodies with one end fixed to the cylindrical circumferential surface are provided at a position near the metal crown and protrude radially in the axial direction of the cylindrical body, and boring This invention relates to a boring device characterized in that it is equipped with a backflow preventer in the middle of the rod.

The specific contents of the present invention will be explained below based on the illustrated embodiments. 1 is an upper core tube, 3 is a lower core tube, 4 is a metal crown, 7 is a lower boring rod, 8 is a backflow preventer, 12 indicates the upper boring rod.

The upper core tube 1 and the lower core tube 3 are integrally connected to each other via a coupling ring 2, and the upper end of the metal crown 4 is opened at the lower end of the lower core tube 3 with an internal thread formed on the inner peripheral surface of the opening. They are integrally connected to each other by screwing in the external threads provided on the outer peripheral surfaces of the parts.

Furthermore, the metal crown 4 is provided with metal tips 5 at its tip, and one end is fixed to the peripheral wall surface within the tube body at approximately equal intervals on the inner peripheral side of the tube body (cylindrical body), and the other end is fixed to the circumferential wall surface of the tube body (cylindrical body) at approximately equal intervals. In this case, as shown in FIG. 2, rod-shaped elastic bodies 6 projecting radially in the axial direction of the metal crown 4 and the lower core tube 3 are provided in two stages in the vertical direction.
Inside the cylinder formed by the rod-shaped elastic body 6
The space between the coupling ring 2 and the coupling ring 2 is defined as a coarse slime collecting section 13.

The rod-shaped elastic body 6 described above is preferably a wire made of twisted metal wire.

Further, a lower boring rod 7 is inserted into the upper core tube 1 along its axis, and the lower end of the lower boring rod is fixedly supported by the above-mentioned coupling ring 2, thereby forming a lower boring rod 7. The space between the inner circumferential wall surface of the upper core tube 1 and the outer circumferential surface of the lower boring rod 7 is defined as a fine slime collecting section 14.

The backflow preventer 8 is connected to the upper end of the lower boring rod 7 using a suitable coupling means such as a coupling, and above it is connected to the upper boring rod 1.
The two ends are also joined using couplings or other suitable joining means.

A hollow chamber 9 is formed in the center of the backflow preventer 8 and communicates with the above-described lower boring rod 7 and upper boring rod 12. , 12, a hollow spherical valve body 11 having a diameter larger than that of each of the openings 7a and 12a is loosely fitted, and a valve body support plate 10 is disposed at the bottom of the hollow chamber.

As shown in FIG. 5, this valve body support plate 10 has a through hole 10b in the center which is large enough that the spherical valve body 11 cannot pass through.
A plurality of other through holes 10a are bored around the through hole 10b.

The above-mentioned spherical valve body 11 may be made of a material such as rubber or plastic, and preferably may be relatively elastic and ball-shaped and have buoyancy. Furthermore, although a spherical valve body is used in this case, it is not necessarily limited to this; for example, a disc or hemispherical valve body is constantly connected to the upper boring rod 12 via a coiled spring that is somewhat weaker than the water supply pressure from the ground. The structure may be such that it is biased in the connection direction.

(Function) In the configuration of the above-described embodiment, the work is carried out according to the normal excavation procedure up to the groundwater level.

The depth of the borehole reaches the groundwater level and the GL
- If the depth is 1.85 m or deeper, a backflow preventer 8 is attached to the upper end of the lower boring rod 7, and the upper boring rod 12 is connected to the core tube 1 and 7 while water is being supplied through these boring rods 12 and 7. Rotate 3 and continue digging work. Excavation is carried out by being gradually scraped away by a metal chip 5 protruding from the tip of a rotating metal crown 4, and the chips such as cobbles, gravel, other fine particles, and sand that are generated at this time are first removed by cobbles, gravel, and other fine particles. The coarse slime R such as sand and gravel is sequentially stored in the coarse slime collecting section 13 in the lower core tube 3 while pushing aside the rod-shaped elastic body 6 which is provided protruding in the axial direction from the inner peripheral surface of the metal crown 4.
In addition, the fine slime S such as fine particles and sand threads between the bored hole wall and the core tubes 1 and 2 and reaches the upper end opening of the upper core tube 1.
As the flow rate gradually decreases, the slime enters the fine slime collecting section provided inside the upper core tube 1 and precipitates, and is sequentially accumulated and stored from the inner bottom thereof.

When the excavation work to a predetermined depth is completed or the coarse or fine slime collecting section is full, water supply from the ground is stopped and the backflow preventer 8
Remove the upper boring rod 12. At this time, due to the difference in specific gravity between the fresh water (muddy water) in the lower boring rod 7 and the wastewater (fresh water or muddy water mixed with slime), the fresh water (muddy water) in the lower boring rod 12 flows back upwards and blows up, but backflow is prevented. The spherical valve body 11 in the vessel 8 is immediately pressed against the opening end of the upper boring rod by its buoyant action to prevent the above-mentioned blown-up water from being blown up. After raising the proposed boring device to the ground in this state, the backflow preventer is removed from the upper end of the lower boring rod 7, and the fine slime S collected in the fine slime collection section 14 of the upper core tube 1 and the lower core tube are collected. The coarse slime R collected in the coarse slime collection section 13 of No. 3 is removed, and when boring is to be continued, these are assembled in the reverse order as described above and the operation is repeated again.

(Effects of the invention) As described above, the present invention includes a cylindrical coarse slime collecting section having a metal crown at the tip, and a cylindrical fine slime collecting section connected to the coarse slime collecting section via a coupling ring. The coarse slime collecting section includes a plurality of boring rods having one end fixed to the cylindrical circumferential surface at a position near the metal crown of the coarse slime collecting section. This rod-shaped elastic body is installed radially in the direction of the axis of the cylindrical body, making it possible to collect not only fine-grained slime such as sand and mud, but also coarse-grained slime such as cobblestones and gravel during excavation work. This eliminates the problem of boring due to coarse slime as in the conventional method.

In addition, since the boring rod is equipped with a backflow prevention device in the middle, when the boring rod is removed from above ground due to the interruption or completion of boring work, fresh water (muddy water) inside the boring rod may be removed. It is possible to prevent the blowing up of fresh water (muddy water) caused by the difference in specific gravity between the water and wastewater (clean water or muddy water mixed with slime), thereby preventing deterioration of the working environment and reducing boring due to collapse of the hole bottom or side wall. It is possible to prevent the induction of

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of the main parts of a boring machine that is an embodiment of the present invention, Figure 2 is an enlarged vertical cross-sectional view of the metal crown, Figure 3 is an enlarged bottom view of the metal crown, and Figure 4 is backflow prevention. FIG. 5 is an enlarged vertical cross-sectional view of the vessel, and is a cross-sectional view taken along the line A--A in FIG. 4. 1... Upper core tube, 2... Coupling, 3... Lower core tube, 4... Metal crown, 6... Rod-shaped elastic body, 7... Lower boring rod, 8... Backflow preventer, 9... Hollow chamber , 10
... Valve body support plate, 11... Spherical valve body, 12
...Upper boring rod, 13...Coarse slime collection section, 14...Fine slime collection section.

Claims (1)

[Scope of utility model registration request] A core tube including a cylindrical coarse slime collection section having a metal crown at the tip, and a cylindrical fine slime collection section connected to the coarse slime recovery section via a coupling ring; The coarse slime collection section has a plurality of rod-shaped elastic bodies with one end fixed to the cylindrical circumferential surface at a position near the metal crown at the tip of the coarse slime collecting section, and oriented toward the axis of the cylindrical body. A boring device characterized in that the boring rod is provided in a radial manner and is provided with a backflow preventer in the middle of the boring rod.