JP3298574B2 - Blistering prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vertical shaft formed by excavating the ground, and the bottom ground of the shaft is subjected to pressurized water pressure (also referred to as lifting pressure).
The present invention relates to a swelling prevention device and a swelling prevention method for preventing swelling due to aging caused by the above.

[0002]

2. Description of the Related Art Conventionally, in civil engineering and construction work,
As shown in FIG. 6, when excavating the ground 1 of the clay layer to form the shaft 2, the earth retaining wall 3 is formed so as to surround a place where the shaft 2 is to be formed, and the earth retaining wall 3 is formed. The excavation of the part surrounded by the squares is performed to form the shaft 2.

If there is a layer of sand and gravel 4 such as sand and gravel under the ground 1, the bottom ground 5 of the shaft 2 is shown by a two-dot chain line due to a temporal change caused by the pressure P of the groundwater. A swelling phenomenon occurs. The bulging of the bottom ground 5 is large at the central portion because the bending moment about the retaining walls 3 and 3 as a fulcrum acts dynamically due to the pressure P to be applied. When such swelling of the bottom ground 5 occurs,
The possibility that the shaft 2 collapses increases.

Therefore, conventionally, as shown in FIG.
Boring the ground 1 before forming
A casing pipe 10 is attached to a boring machine 9 of a high-pressure injection device 8 at a location 7 corresponding to the bottom ground where the bottom ground 5 of the shaft 2 is to be formed.
The hardened material 11 is jet-injected through the casing pipe 10 while rotating to form a solidified body 12 at a portion 7 corresponding to the bottom ground, and the bottom ground 5 is improved.

[0005]

However, in this conventional apparatus for preventing swelling, if the thickness of the consolidated body 12 is small, the bottom ground 5 will not be able to withstand the pressurized water pressure P and will swell due to aging. However, there is a problem that the certainty of preventing the bulging of the bottom ground 5 is poor.

In order to prevent this, it is conceivable to increase the thickness of the consolidated body 12, but in order to increase the thickness of the consolidated body 12, a considerable amount of Since the hardening material 11 must be injected, a new problem arises in that the cost required for measures to prevent the bottom ground 5 from bulging becomes too high.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the cost required for the measures to prevent the bulging of the slab while reliably preventing the bulging of the ground at the bottom of the shaft. It is an object of the present invention to provide an apparatus and a method for preventing swelling.

[0008]

According to a first aspect of the present invention, there is provided an apparatus for preventing swelling of a ground, wherein a bottom ground of a shaft formed by excavating the ground is swollen due to a pressure of water to be confined. In order to prevent the ground from rising, a hardening material is filled in a portion corresponding to the bottom ground where the bottom ground is to be formed, and a consolidated body is formed. An anchor member is provided on the consolidated body, and the hardening material is filled by a high-pressure jet stirring device.
The high-pressure injection device guides the hardening material from the tip.
A casing pipe for jetting the hardening material and the casing;
A boring hole is formed while rotating a single pipe.
And the anchor member is
Pressed into the compact using a boring machine
It is characterized by being.

According to the first aspect of the present invention, the bottom ground is improved by filling the hardened material into a portion corresponding to the bottom ground to form a consolidated body, and is provided below the consolidated body. The ground to be bonded and the consolidated body are joined by the anchor member, so that the bottom ground can be prevented from bulging without increasing the thickness of the consolidated body, and as a result, the cost required to prevent Reduction can be achieved. In addition, jet injection by high pressure
Since the hardening material is filled into the area corresponding to the ground,
The filling work is easy. In addition, boring of high pressure injectors
Press the anchor member into the consolidated body using a machine.
And can use existing equipment,
Installation work of the anchor member can be easily performed .

[0010]

[0011]

According to a second aspect of the present invention, there is provided the apparatus for preventing swelling according to the first aspect , wherein the anchor member has a resistance protrusion which resists a force in a pulling-out direction. Features.

[0013] According to the second aspect of the present invention, since the resistance protrusions are formed on the anchor member so as to resist the force in the pulling-out direction, the anchor member is difficult to come off and the bottom ground is surely swollen. Can be prevented.

[0014]

[0015]

According to a third aspect of the present invention, in the apparatus for preventing swelling according to the first aspect , the anchor member comprises a steel pipe, and screw blades are formed at both ends of the steel pipe. The steel pipe is rotated using the boring machine, guided by screw blades and pushed into the consolidated body, and the screw blades are also used as resistance protrusions that resist a force in a drawing direction. Is what you do.

According to the third aspect of the present invention, since the steel pipe as the anchor member can be smoothly screwed into the consolidated body by the screw blade, the installation work of the anchor member is further facilitated and the screw is removed. Since the wing blades act as resistance projections that resist the force in the pulling-out direction, the steel pipe itself does not easily come off, and the bottom ground can be reliably prevented from bulging. Furthermore, since the existing facilities can be used, the work of pushing the steel pipe can be performed quickly.

The invention described in claim 4 is the same as the claim 2.
Wherein the steel pipe is pressed into the consolidated body in a semi-solid state of the consolidated body.

According to the fourth aspect of the present invention, since the steel pipe is pushed before the consolidated body is completely solidified, the installation time of the steel pipe can be reduced.

The invention described in claim 5 is the third invention.
In the swelling prevention device described in the above, if the ground existing immediately below the consolidated body is a gravel layer, the tip of the steel pipe pipe reaches the hard ground layer existing under the gravel layer It is characterized by having.

According to the fifth aspect of the present invention, since the tip of the steel pipe is cut into the hard stratum, the steel pipe itself is more difficult to come off, and therefore the swelling of the bottom ground can be further prevented. .

Further, in the method for preventing swelling according to claim 6 , before forming a shaft formed by excavating the ground, the ground is drilled to form a bottom ground of the shaft from a borehole. A hardened material is filled in a portion corresponding to the bottom ground to be formed to form a consolidated body, and in a semi-solidified state of the consolidated body, an anchor member is pushed into the consolidated body through the boring hole, and a lower portion of the consolidated body is formed. The present invention is characterized in that the bottom ground is prevented from bulging due to the pressure of the confined water by connecting the existing ground and the solidified body.

According to the invention of claim 6 , it is possible to prevent the bottom ground from bulging without increasing the thickness of the consolidated body,
As a result, it is possible to reduce the cost required for the measures for preventing board bulging. Further, the anchor member can be installed on the bottom ground using the existing boring holes and existing facilities.

[0024]

1 is a sectional view taken along the line XX shown in FIG. 3, FIG. 2 is a sectional view taken along the line YY shown in FIG. 3, and FIG. 3 is a shaft structure according to the present invention. FIG. 4 is a plan view of the bottom ground portion of the body, and FIG. 4 shows that a hardened material is filled in a portion corresponding to the bottom ground to form the bottom ground of the ground surrounded by the retaining wall before forming the shaft, thereby forming a consolidated body. Work process and Fig. 1
And FIG. 5 is a side view showing an example of the anchor member shown in FIG. 1.

1 to 3, reference numeral 20 denotes a clay ground, reference numeral 21 denotes a gravel layer existing below the ground 20, and reference numeral 22 denotes a hard geological layer such as rock existing below the gravel layer 21. It is.

An earth retaining wall 24 is driven into the ground 20 so as to surround the ground 20 where the shaft 23 is to be formed. A reinforcing support 25 is spanned between the retaining walls 24, 24 to form a shaft structure.

Before excavating the shaft 23, the ground 20 is drilled by a boring machine 27 and a casing pipe 28 of a high-pressure injection device 26 shown in FIG. The casing pipe 28 is attached to the boring machine 27 and rotated, thereby forming a boring hole 29. This boring is performed until the boring hole 29 reaches a location 30 corresponding to the bottom ground where the bottom ground of the shaft 23 is to be formed.

At the end of the casing pipe 28, a jet injection nozzle 31 is provided. The casing pipe 28 jets a hardening material (for example, a mixture of cement, water, and air) 32 from the jet injection nozzle 31 toward the bottom ground equivalent portion 30 while guiding the hardening material 32. The soil and sand existing in the bottom ground equivalent portion 30 are blown up to the ground through the boring hole 29 by jetting of the hardening material 32. The casing pipe 28 is pulled up while rotating, and as a result, as shown in FIG. 4B, the bottom ground equivalent portion 30 is replaced with a ground mixed with a hardening material 32, and the hardening material 32 is solidified to form a columnar shape. Is formed.

As shown in FIG. 3, the ground improvement work for the bottom ground equivalent portion 30 is performed on the entire region surrounded by the retaining wall 24 so that the peripheral portions of the consolidated body 33 overlap with each other.

Next, an anchor member 34 is set on the boring machine 27 of the high-pressure injection device 26 as shown in FIG. The anchor member 34 is constituted by a cylindrical steel pipe shown enlarged in FIG. Screw blades 35 and 36 are formed at both ends of the anchor member 34. At the upper end of the anchor member 34, for example, a screw (not shown) is formed.

The anchor member 34 is provided with the boring hole 2
While being rotated through 9, it is pushed toward the bottom ground equivalent part 30. When the anchor member 34 is pushed into the boring hole 30 by a predetermined amount, a casing pipe 37 as an auxiliary tool is set on the boring machine 27 as shown in FIG. This casing pipe 3
At the lower end of 7, a screw (not shown) that is screwed with the screw formed at the upper end of the anchor member 34 is formed.
The casing pipe 37 and the anchor member 34 are connected by this screw.

The anchor member 34 is screwed into the fixed body 33 by rotating the casing pipe 37 in one direction. The operation of screwing the anchor member 34 into the consolidated body 33 is performed while the consolidated body 33 is in a semi-solid state.
This is desirable from the viewpoint of quickly screwing the anchor member 34.

As shown in FIG. 4D, the anchor member 34 is moved until the screw blade 35 passes through the gravel layer 21 to reach the hard ground layer 22 and the screw blade 36 is connected to the solidified body 33. It is desirable to screw it into the consolidated body 33 until it is buried. The screw blades 35, 36
Acts as a resistance protrusion that resists the force in the pull-out direction when screwed into the consolidated body 33,
It becomes difficult for the anchor member 34 to come off.

When the operation of pushing the anchor member 34 is completed, the casing pipe 37 is rotated in the direction opposite to the pushing direction, the connection between the casing pipe 37 and the anchor member 34 is released, and the casing pipe 37 is pulled up. Thereafter, formation work of the shaft 23 is performed,
A shaft structure is constructed.

As shown in FIGS. 1 to 3, the anchor members 34 are arranged at appropriate intervals, and the arrangement intervals and the number of the anchor members 34 are added to the size of the shaft 23 and the solidified body 33. It is appropriately determined according to the groundwater pressure and the like. 1 to 3 show a state in which the anchor members 34 are arranged at equal intervals. When the anchor member 34 is provided in this manner, the distance (span S) from the retaining wall 24 that mechanically acts as a fulcrum of the bending moment to the retaining wall 24 is:
Also divided mechanically by an anchor member 34 which acts mechanically as a fulcrum of the bending moment, the span S 'between the fulcrum
(FIG. 1), the bending moment due to the pressurized water pressure P can be reduced, thus increasing the resistance of the improved bottom ground to the bending moment,
Swelling of the bottom ground can be reliably prevented.

[0036]

According to the present invention, the bottom ground is filled with a hardening material to form a consolidated body, thereby improving the bottom ground and consolidating with the ground existing below the consolidated body. Since the body and the body are joined by an anchor member, it is possible to reliably prevent bulging of the bottom ground without increasing the thickness of the consolidated body, and to reduce the cost required for measures to prevent bulging of the board. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along the line XX shown in FIG.

FIG. 2 is a sectional view taken along the line YY shown in FIG.

FIG. 3 is a plan view of a bottom ground portion of the shaft structure according to the present invention.

FIG. 4 is a diagram showing an operation process and a process of forming a consolidated body by filling a hardening material into a portion corresponding to the bottom ground where the bottom ground of the ground surrounded by the retaining wall before forming the shaft shown in FIG. 1 is to be formed. 1
FIGS. 7A and 7B are schematic diagrams schematically illustrating a process of pushing an anchor member into a consolidated body shown in FIG. 7A, and FIG. 9A is a schematic diagram illustrating an operation of improving a bottom ground in order to prevent the bottom ground of a shaft from being swollen; , (B) is a schematic view showing a state where an anchor member is set on a boring machine, (c) is a schematic view showing a state where the anchor member is pushed halfway into the improved bottom ground, and (d) is an improved state It is a schematic diagram which shows the state in which the anchor member was buried in the bottom ground.

FIG. 5 is a side view showing an example of the anchor member shown in FIG.

FIG. 6 is a view for explaining the bulging of the ground at the bottom of the shaft.

FIG. 7 is a schematic view showing an operation of improving the bottom ground in order to prevent the bottom ground of the shaft from bulging.

[Explanation of symbols]

 20, 22 Ground 23 Vertical shaft 30 Bottom ground equivalent part 32 Hardened material 33 Solidified body 34 Anchor member

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-25828 (JP, A) JP-A-9-317373 (JP, A) JP-A-3-228995 (JP, A) JP-A-63-1988 300106 (JP, A) JP-A-52-126003 (JP, A) JP-A-51-55111 (JP, A) JP-A-48-57409 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) E02D 31/10 E02D 3/12 102 E02D 5/54 E02D 5/80 E21D 1/10

Claims (6)

(57) [Claims] 1. The bottom of a shaft formed by excavating the ground
To prevent the board from bulging due to the water pressure
Then, the bottom ground is hardened at a place corresponding to the bottom ground where the bottom ground is to be formed.
The material is filled to form a compact, and the compact
An anchor for connecting the ground existing below and the solidified body
A member is provided on the consolidated body.And The filling of the curing material is performed by a high-pressure injection device,
The high-pressure injection device guides the hardened material while guiding the hardened material from the tip.
Pipe for jetting chemical material and casing
Boring that forms a boring hole while rotating the pipe
Ng Machine The anchor member is moved forward using the boring machine.
Being pressed into the compact Board characterized by
Blistering prevention device. Wherein Oite to claim 1, wherein the anchor member, board blisters prevention device, characterized in that it has a resistance projection to resist withdrawal force. 3. The steel pipe according to claim 1 , wherein the anchor member comprises a steel pipe, and screw blades are formed at both ends of the steel pipe. The steel pipe is rotated using the boring machine and guided by the screw blade. Wherein the screw blade is also used as a resistance protrusion which resists a force in a pulling-out direction. 4. The apparatus according to claim 3 , wherein the steel pipe is pushed into the consolidated body in a semi-solid state of the consolidated body. 5. The method according to claim 3 , wherein when the ground immediately below the consolidated body is a gravel layer, the tip of the steel pipe extends to a hard ground layer below the gravel layer. A swelling prevention device, characterized in that: 6. Before forming a shaft formed by excavating the ground, the ground is bored, and a hardening material is filled into a portion corresponding to the bottom ground where the bottom ground of the shaft is to be formed from a borehole, and then solidified. Forming a consolidated body, pressing the anchor member into the consolidated body through the boring hole in a semi-solidified state of the consolidated body, and joining the ground existing under the consolidated body to the consolidated body. And preventing the bottom ground from bulging due to the water pressure.