JP2001073354A - Injection pipe and ground injection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide an injection method capable of ground improvement in a short time by providing a plurality of injection holes in an injection pipe, providing a bag body so as to cover partial injection holes, and filling them with an injection material in slots to form a packer. SOLUTION: Slots 2 are drilled so that a plurality of their rows are formed in a ground 1, and the injection pipe 3 is inserted to fill the injection material. A number of injection holes 4 are vertically opened in the injection pipe 3 in the longitudinal direction, and bag bodies 5 are attached at several parts. The bag body 5 is,made of cloth, rubber or the like, is size for filling a space between the slot 2 and the injection pipe 3, and when swollen, it is a shape in which the packer is in the form of a donut. The injection material is cement, water glass, solution or the like. When injection is started, at first, the bag body 5 is filled to be swollen, the packer is formed, and a plurality of spaces are formed in the slot 2. Next, it fills the space between the packers from the injection hole 4, and is uniformly filled into the ground 1. Thereby injection working can be performed continuously and easily and ground improvement can be performed uniformly in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection method for consolidating and stabilizing a soft ground or a leaked ground by using an injection material to cut off water leakage or spring water.

[0002]

2. Description of the Related Art Conventionally, as a ground injection method, an injection method of injecting an injection material into the ground has been used for the purpose of consolidating and stabilizing a foundation for building a building or soft ground. I was

[0003] As a method of pouring into a foundation or soft ground when constructing a building, a rod (a single pipe rod or a double pipe rod is selected depending on the chemical solution used) is specified in the foundation or soft ground prior to construction. After the injection material is pressed into the ground, the rod is pulled up by 20 to 100 cm, a rod-type injection method of repeating injection, or a double packer is inserted into the outer pipe of the injection, and the injection material is pressed from an arbitrary injection hole. Thereafter, a double pipe double packer method in which the double packer is moved to the next injection hole and injection is repeated again is exemplified.

There is also a method of improving the ground by simultaneously injecting the injected material into the ground from a plurality of injection spaces. According to this method, an outer pipe having a discharge port opened on a pipe wall covered with a rubber sleeve is installed in a hole provided in the ground, and then the outer pipe has an injection port which is shifted from the discharge port. After inserting the inner tube, placing the packer in the gap between the inner tube and the outer tube, forming a plurality of injection spaces surrounded by the inner and outer tubes and the packer, introducing the injection material into the inner tube, and injecting the injection material into the injection port This is a method in which the rubber grout is injected into the respective spaces through a discharge port, and further expanded by pushing the rubber sleeve through the discharge port, so that the sleeve grout injected between the outer pipe and the ground is broken and penetrated into the ground (Patent No. 27
No. 72637).

[0005] The injection materials used in these injection methods include solution-type injection materials, cement-type injection materials, and water-glass-type injection materials. Edited by the committee, published by Industrial Technology Service Center Co., Ltd., p. 156).

[0006]

However, these methods have the following problems.

The rod type injection method is a method in which an injection material is discharged from the rod tip by a discharge pressure, and is the simplest method. However, since the injection material is easily discharged intensively to a fragile portion in the ground. , It is difficult to improve the ground uniformly,
Since the packing effect around the rod cannot be expected, the injection material frequently leaks from the vicinity of the rod.

[0008] In the double pipe double packer method, since the movement of the double packer position and the injection work are repeatedly performed,
Complicated work and time are required to complete one injection, and since the double packer moves, the filling operation of the injection material must be performed after the movement of the double packer is completed, which is not efficient. There is a problem that it is difficult to say that it is an injection method.

The method of simultaneously injecting the injection material into a plurality of injection spaces has a problem that when the injection tube is withdrawn at the end of the injection operation, the injection tube cannot be pulled out, especially when a quick-hardening cement injection material is used. In addition, when the injection pipe is removed, voids are formed in the long holes, so that it is necessary to fill the voids. Therefore, the injection operation is complicated, and there is a problem that it is difficult to say an efficient injection method.

Further, in the method of simultaneously injecting an injection material from a plurality of injection spaces, it is necessary to form a packer in advance in order to form injection spaces independent of each other. And there is a problem that the inner tube may not be easily inserted.

[0011]

The inventors of the present invention have conducted intensive studies and have found that in the rod type injection method, the injection material leaks from the vicinity of the rod, the double packer method and the method of simultaneously injecting the injection material into a plurality of injection spaces. It is superior to the rod-type injection method and has the same improvement effect as the double-packer method and the method of simultaneously injecting the injection material from multiple injection spaces. In addition, the present inventors have found a ground injection method capable of obtaining an effect of solidifying and stabilizing the ground, and have reached the present invention.

[0012]

That is, the present invention relates to an injection tube having a plurality of injection holes and a plurality of bags arranged so as to cover a part of the injection holes. . And
A ground injection method comprising inserting the injection pipe into the ground and then injecting an injection material from the injection pipe, wherein after inserting the injection pipe into the ground, the fluid is injected into the bag from the injection pipe. And a bag is formed by inflating the bag body to form a packer, and after fixing an injection pipe to the ground, an injection material is injected into the ground.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in accordance with the order of the injection method (see FIG. 1).

The present invention relates to an injection pipe and a ground injection method for consolidating and stabilizing a foundation or soft ground in building a building.

In the present invention, although the injection form changes depending on the target ground, the present invention can be applied to the ground made of any soil such as gravel soil, sandy soil, and cohesive soil.

In the present invention, first, a long hole 2 is formed in the ground 1. Particularly in the case of building a building in the ground injection method, it is necessary to uniformly solidify and stabilize the entire ground injection point so that the building does not tilt or sink. Therefore, it is preferable that the long holes 2 are perforated so as to form a plurality of rows.

Next, the injection tube 3 of the present invention is inserted into the long hole 2.

The injection pipe 3 has a large number of injection holes 4 perpendicular to the longitudinal direction, and a bag 5 is attached so as to cover several places of the injection holes 4.

As the material of the injection pipe 3, any material such as PVC or steel can be used. However, it is easy to re-excavate, the workability of the injection hole 4, the insertability into the long hole 2, and handling such as transportation. From the viewpoint of easiness, a product made of PVC is preferable.

The size and size of the injection tube 3 vary depending on the length of the injection tube 3 and the diameter of the long hole 2.
There is no particular limitation.

As the material of the bag 5, most materials such as cloth, rubber, polyethylene, nylon, and vinyl bags can be used, but when the injection tube 3 is inserted into the long hole 2, the bag is damaged due to scratches or the like. Cloths are preferred because they are less dangerous. Among the cloths, those having a waterproof inner surface made of rubber latex or the like, and those having a vinyl sheet set inside the cloth are preferable from the viewpoint of improving waterproofness.

The size of the bag 5 may be sufficient to fill the space between the long hole 2 and the injection tube 3.

The shape of the bag 5 is preferably a donut when the bag 5 is inflated because the packer is easy to process and easily forms a packer.

The bag 5 is attached to the injection pipe 3 and both ends of the bag 5 are tied with a string or fixed with an adhesive or a hose band so that the injected material does not leak from both ends. To In these, attachment to the injection tube 3 is easy,
A method in which both ends are fixed with a hose band is preferable from the viewpoint of improving waterproofness. In order to form a donut-shaped packer when the bag body 5 is inflated, an annular sheet obtained by bonding the ends of a cylindrical sheet with an adhesive or the like is used as the injection pipe 3.
And inflate the bag 5.

The distance between the bags 5 is not particularly limited, but is preferably 1 m or less, because the ground can be improved by reducing the space between the partitions of the bags 5.

If the distance between the bag bodies 5 is increased, there is a possibility that the ground cannot be uniformly improved when the ground is formed of alternating layers having different grain sizes and water permeability.

A bag 5 may be attached to the tip of the injection pipe 3, but the ground at the tip of the injection pipe 3 can be improved, and the bag 5 is not attached to the tip of the injection pipe 3. Preferably, a cap 6 is attached. When the bag 5 is attached to the tip of the injection tube 3, the injection material may be blocked by the swelled bag 5 and may not be easily injected into the tip of the long hole 2.

After the injection tube 3 thus manufactured is inserted into the long hole 2, an injection material is injected and the injection operation is started.

As the injection material, any type such as a cement type, a water glass type and a solution type can be used. When a building is built around the ground injection point, it can be injected even at a low discharge pressure so that the injection material is not injected to the lower part of the surrounding building, the permeability is large, the strength of the injection material itself It is necessary to use an injection material having a low homogel strength. If the homogel strength is high, the ground may be raised, and uniform ground improvement may not be possible. If there are wells or rivers around the ground injection point, the injection material is rapidly hardened by using a highly safe cement-type injection material and a cement-type rapid hardening material, and the injection material is lost to the well or river. It is preferable to prevent flowing.

The water-to-cement ratio (W / C) of the injection material, particularly the cement injection material system, is to prevent the injection material from flowing into wells and rivers,
In view of workability at low pressure and strength balance with the ground, 100 to 1000% is preferable, and 250 to 600%.
% Is more preferred. However, when a cement-based rapid-hardening material is used in combination with the cement-based quick-injecting material, the W / C cement includes the solid content of the cement-based quick-hardening material.

For an injection material having an extremely short curing time,
It can be used by increasing the diameter of the injection hole 4 opened in the injection tube 3. The two-pack injection material can be used by arranging two injection tubes 3 in parallel.

By injecting the injection material from the injection pipe 3, the bag 5 is first filled and swells like a balloon to form a packer, thereby forming a plurality of spaces inside the long hole 2. By continuing the injection, a large number of injection holes 4 opened in the injection tube 3 are formed.
More filling material fills the space between the packers and then the ground 1
Inject evenly. In order for the bag body 5 to form a packer first, the hole diameter of the injection hole 4 covered with the bag body 5 may be larger than that of the injection hole 4 for injecting the injection material into the ground 1. The number of the injection holes 4 covered by the material may be larger than the number of the injection holes 4 for injecting the injection material into the ground 1.

As another embodiment, first, a non-hardening fluid such as water may be injected to inflate the bag 5 and then an injection material may be injected.

In the case of fragile ground in which the long hole 2 is likely to collapse due to the ground, construction can be carried out without problems by using the outer pipe together or by using a seal grout material. However, the outer pipe is not used because the work is easy. Is preferred.

[0035]

FIG. 1 shows an injection pipe 3 and an injection method.

(Preparation of Injection Tube 3) Length 6m, Name 25
A cap 6 on one end of the injection pipe 3 made of a PVC pipe
Was attached. Four 1 mm diameter injection holes 4 of 2 mm diameter are formed at equal intervals in the longitudinal direction of the PVC pipe on the outer peripheral surface of the PVC pipe (the injection holes 4 on the opposite side of the pipe are not shown). Opened. Five cylindrical-shaped cloths waterproofed by applying rubber latex were attached so as to cover the injection hole 4, and both ends were firmly fixed with a hose band to form a bag body 5 (in FIG. 1, a bag body). 5 only two). Further, two injection holes 4 each having a diameter of 1.5 mm were opened in the middle of the space formed by the bag body 5 (the injection holes 4 on the opposite side of the pipe are not shown). Thus, the injection tube 3 was produced.

Example 1 A long hole 2 having a diameter of about 100 mm and a length of 6 m was drilled in the ground 1 using a boring machine. After inserting the injection tube 3 into the long hole 2,
The injection material was pumped and injection was performed. As the injection material, a mixture of a cement-based injection material and a cement-based rapid hardening material was used. The concentration of the injection material was adjusted so that W / C = 300%. The injection conditions were as follows:
The discharge pressure was set to 0.2 MPa, and 600 liters of the injection material were injected into the injection pipe 3. During the injection, no injection material leaked from the gap between the long hole 2 and the injection pipe 3 to the ground surface. It was clearly determined that the ground 1 and the packer were integrated. After the injection, the area around the injection pipe 3 was excavated to observe the state of improvement of the ground. As a result, the injection material was firmly and uniformly fixed around the injection pipe 3 regardless of the position of the injection pipe 3, and the surrounding soil was involved. Had solidified.

(Example 2) First, water is pressure-fed to form a bag 5
After inflating and forming a packer, pumping the injection material,
Except having injected, it implemented similarly to Example 1. As a result, no leakage of the injected material from the gap between the long hole 2 and the injection pipe 3 to the ground surface occurs at all as in the first embodiment, and the excavation observation result shows that the injected material is firmly and uniformly fixed around the injection pipe 3. Then, the surrounding earth and sand were involved and solidified.

(Embodiment 3) φ100 m in the vertical direction using a boring machine with respect to the ground on which a building is to be built.
A plurality of long holes 2 having a length of about m and a length of 6 m were formed in the ground 1 so as to form a plurality of rows. The injection pipes 3 were inserted one by one into the plurality of long holes 2, and the injection material was fed under pressure to perform injection. As the injection material, a mixture of the cement injection material used in Example 1 and the cement-based rapid hardening material was used. The injection conditions were a discharge rate of 30 l / min and a discharge pressure of 0.2 MPa, and 600 l of the injection material was injected into the injection pipe 3 per injection pipe. One hour after injection,
The target ground was excavated. As a result, excavation work on the ground to be injected was easy. Also, because the excavation surface did not collapse,
It was confirmed that the target ground was entirely solidified. Furthermore, since the hardened material was used after excavation around the ground to be injected, the injected material was not injected into the surrounding area outside the target ground and did not solidify. Also, the injected material did not escape to nearby wells and rivers.

(Comparative Example 1) The procedure was performed in the same manner as in Example 1 except that the bag 5 was not attached to the injection tube 3. During the injection, a large amount of injected material leaked from the gap between the long hole 2 and the injection pipe 3 to the ground surface. After the injection, the area around the injection pipe 3 was excavated and the condition of the ground improvement was observed. As a result, a very small amount of the injection material was solidified around the injection pipe 3, but the surrounding soil was not solidified at all. Due to the large amount of leakage of the injected material, the injected material was hardly pressed into the ground 1.

[0041]

By using the injection pipe of the present invention, the injection operation can be performed continuously and easily, so that the ground can be uniformly improved in a short time. Furthermore, the injection pipe of the present invention is intended for ground improvement such as stabilization excavation, and does not fix the injection pipe so strongly as to have an anchor effect. This has the advantage that the injection pipe fixed inside can be broken and easily excavated without extracting the injection pipe. Further, the injection tube has a simple structure and is easy to produce, and its industrial applicability is extremely large. Further, even if the ground is formed by alternately forming layers having different grain sizes and water permeability, the ground can be uniformly improved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an injection tube inserted into a long hole to form a packer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground 2 Long hole 3 Injection pipe 4 Injection hole 5 Bag body 6 Cap

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Toshio Kawauchi 1-4-1 Yurakucho, Chiyoda-ku, Tokyo F-term (reference) 2D040 AA04 AC02 AC03 AC04 AC05 BB03 CA01 CA02 CB03 DA12 DC02

Claims (3)

[Claims] 1. An injection tube having a plurality of injection holes and a plurality of bags arranged so as to cover a part of the injection holes. 2. A ground injection method comprising: inserting the injection pipe according to claim 1 into the ground; and injecting an injection material from the injection pipe. 3. After the injection pipe according to claim 1 is inserted into the ground, a packer is formed by injecting a fluid into the bag from the injection pipe to inflate the bag, and the injection material is inserted into the ground. Ground injection method characterized by injection.