JP4448407B2 - Ground improvement material injection device - Google Patents

Description

  The present invention provides a natural ground improvement material injected into the natural ground in order to improve or reinforce the natural ground (general ground, ground, slope, underground etc. are collectively referred to as “natural ground” in the present invention). The present invention relates to a ground improvement material injection device for injection.

Conventionally, when excavating tunnels and underground cavities, etc., a natural ground improvement method that improves or reinforces natural ground to stabilize and facilitate excavation work (long tip receiving method, natural mountain tip receiving reinforcement method, etc.) The “general improvement method” is collectively referred to.
In other words, a pilot hole of a predetermined depth is drilled in a natural ground (for example, in front of a tunnel face) and a steel pipe is inserted into the pilot hole, or a steel pipe having a drilling means installed at the tip thereof is set to a predetermined depth. In this way, a liquid ground improvement material is press-fitted into the steel pipe from the front by a pump or the like, and the steel pipe is embedded in the drilled hole, and the through-hole drilled in the outer periphery of the steel pipe is inserted. It is injected from the hole into the pilot hole or drilling hole and penetrates into the natural ground.

At this time, when the prepared hole or drilling hole (hereinafter collectively referred to as “prepared hole”) is inclined and the front side is low, the injected natural ground improvement material is the bottom portion of the prepared hole (the gap between the prepared hole and the steel pipe). From the front of the excavation), the ground improvement material having expansibility and foaming property overflows at the mouth, or the predetermined pressure is not maintained in the pilot hole, Since the mountain improving material does not penetrate into the natural ground, a means for closing the mouth portion is used.
For example, a cloth (waste) is inserted into the mouth part, a partition wall is formed by caulking seal with cloth (waste) and resin or cement at the mouth part, or a resin or cement is inserted into the bag body (packer) inserted into the mouth part. And partition walls are formed by the expanded bag body (see, for example, Patent Document 1).

JP 2000-310094 A (page 5-6, FIG. 4)

However, the invention disclosed in Patent Document 1 is a bag body in which a material for consolidation (supplied as liquid A) is enclosed near one end of a steel pipe for injecting a natural ground improvement material ( Packer) is installed, the steel pipe is inserted into the pilot hole, and the bag body is filled with the consolidated injection material (supplied as B liquid) in a state where the bag body is located at the mouth portion. There is.
(A) Receiving means for filling the bag body with the solid injection material (liquid B), for filling the bag body with the solid injection material (liquid B) (for example, a filling tube and a one-touch coupler having a predetermined length) Etc.), the structure of the bag body becomes complicated, and the manufacturing cost of the bag body itself and the natural ground improvement material injection device increases.

(B) Moreover, since the following operation | work is needed in order to fill a bag body with a consolidated injection material (B liquid), a series of construction for ground improvement is overdue, and it becomes a cause of a construction period delay.
For example, arrangement of a pump for pumping the consolidated injection material (liquid B), start-up of the pump, connection between a filling tube installed in the pump and a filling tube installed in the bag, a valve for filling It is necessary to clean the operation of the filling head and one-touch coupler installed in the pump after filling.
(C) Also, prior to the injection of the natural ground improvement material into the natural ground, as the work separate from the injection of the natural ground improvement material, the material for consolidation (liquid A) is sealed in the bag body in advance, so the work is complicated. As a result, a series of construction work for improving the natural ground is delayed, which contributes to the delay of the construction period.

(D) Furthermore, when the pilot hole is deep (for example, 12 m or more), the ground improvement material is not uniformly injected over the entire length of the pilot hole. Further, even when injected, since the predetermined pressure is not applied to the natural ground improvement material over the entire length of the pilot hole, the penetration into the natural ground may be uneven and insufficient.
For example, if an injection hole for ground improvement material is provided at the tip of the steel pipe and the ground improvement material is injected from the back of the pilot hole (same as the tip of the steel pipe), the fluidity of the ground improvement material deteriorates during the injection. Then (starting solidification), the ground improvement material does not reach the mouth part, or the injection pressure is depleted on the way and almost disappears at the mouth part.
On the other hand, when a ground improvement material injection hole is provided over the entire length of the steel pipe, and a natural ground improvement material is to be injected over the entire length of the lower hole, a large amount of ground improvement material is injected from the previous injection hole. Thus, the injection amount from the injection hole near the tip of the steel pipe is reduced. In particular, when the lower hole is inclined and the front is low, or when the diameter of the steel pipe is small, the injection volume depends on the head pressure (static pressure) of the ground improvement material and the flow resistance of the inner wall of the steel pipe, which increase as the injection hole becomes closer to the front The non-uniformity becomes remarkable.

  The present invention has been made to solve such a problem, and the bag body has a simple structure, enables simple construction, and further improves the natural ground over the entire length of the pilot hole. It aims at providing the natural ground improvement material injection | pouring apparatus which can inject | pour uniformly.

(1) A natural ground improvement material injection apparatus according to the present invention, a natural ground improvement having a substantially liquid-tight bag body having flexibility and a steel pipe penetrating the bag body substantially liquid-tightly. For injecting material,
A receiving means for receiving a ground improvement material at one end of the steel pipe; a filling hole for filling the ground body with the ground improvement material at a position of the bag body of the steel pipe; An injection hole for injecting a natural ground improving material into the natural ground is provided near the other end than the bag body,
When the ground improvement material is supplied to the steel pipe via the receiving means, first, the ground body improvement material is filled into the bag body via the filling hole, and then, via the injection hole. A natural ground improvement material is injected into the natural ground.

(1) A groundstone improving material injection device according to the present invention includes a plurality of substantially liquid-tight bag bodies having flexibility, and a steel pipe penetrating the plurality of bag bodies substantially liquid-tightly. A ground improvement material injection device for injecting natural ground improvement material into a mountain,
Receiving means for receiving the ground improvement material at one end of the steel pipe; and a plurality of ground strength improvement materials for filling each of the plurality of bag bodies at the positions of the plurality of bag bodies of the steel pipe. A plurality of injection holes for injecting a natural ground improving material into a natural ground are provided between the filling hole and the plurality of bag bodies of the steel pipe,
When the ground improvement material is supplied to the steel pipe via the receiving means, first, the plurality of bags are filled with the ground improvement material via the plurality of filling holes, and then The natural ground improvement material is injected into the natural ground via the injection hole ,
A constant pressure on-off valve for injection that opens when reaching an injection pressure that is a predetermined pressure in each of the plurality of injection holes and closes at a pressure lower than the injection pressure is installed,
Of the constant pressure on-off valve for injection, the injection pressure increases as the constant pressure on-off valve for injection installed at a position near one end of the steel pipe .

  (2) In addition, a constant pressure on-off valve for injection that is opened when reaching an injection pressure that is a predetermined pressure and closes at a pressure lower than the injection pressure is installed in the plurality of injection holes. .

  (3) Further, each of the plurality of filling holes is opened when reaching a filling pressure that is lower than an injection pressure of an injection constant pressure on-off valve installed at a position closest to the other end of the steel pipe. A filling constant pressure on-off valve that is closed at a pressure lower than the filling pressure is provided.

  (4) Moreover, the check valve for filling which passes a natural ground improving material only toward the said bag body is installed in each of these said several holes for filling.

  (5) A plurality of groups of a pair of annular bodies having elasticity are installed on the outer surface of the steel pipe, and the plurality of groups are respectively surrounded by a plurality of groups of steel pipe penetration portions through which the steel pipes of the plurality of bags penetrate. It is characterized by being bound to the steel pipe through a pair of annular bodies.

  Hereinafter, embodiments will be described with reference to the drawings. In the following drawings, the same portions or portions having similar functions are denoted by the same reference numerals, and a part of the description is omitted.

[Embodiment 1]
FIG. 1 is a side view in cross section of the upper half for explaining a ground improvement material injecting apparatus according to Embodiment 1 of the present invention. In FIG. 1, a ground improvement material injecting device 1 (hereinafter referred to as “injecting device 1”) has a substantially liquid-tight bag body 10 having flexibility and a bag body 10 penetrating substantially in a liquid-tight manner. And a steel pipe 20.
The steel pipe 20 has a receiving means 30 for receiving the natural ground improving material at one end (right end in the figure) and a sand pipe to prevent intrusion of earth and sand at the other end (left end in the figure). The tip closing means 40 (hereinafter referred to as “cone cap 40”) is installed.
The receiving means 30 is formed of a different diameter socket 31 screwed to the steel pipe 20 and a joint means 32 (for example, a one-touch coupler) screwed to the different diameter socket 31, and the joint means 32 supplies a natural ground for supplying a natural ground improving material. It is connected to an improvement material supply pipe (connected to a pressure pump for supplying a natural ground improvement material (not shown)). The cone cap 40 is screwed or fitted to the steel pipe 20.

And in the steel pipe 20, the hole 21 for filling the bag body 10 with the natural ground improvement material in the position of the bag body 10, and the other edge part (left end part in the figure) near the bag body 10 are located. The injection hole 22 for injecting the natural ground improvement material into the natural ground is formed at the position of.
Then, the filling hole 21 and the injection hole 22 are opened when the filling pressure (P1) and the injection pressure (P2), which are predetermined pressures, respectively, are opened, and from the filling pressure (P1) and the injection pressure (P2). A constant pressure on-off valve 50 for filling and a constant pressure on-off valve 60 for injection (hereinafter may be collectively referred to as “constant pressure on-off valve”) are installed, which close at low pressure.

  FIG. 2 is a cross-sectional view illustrating an on-off valve in the injection apparatus 1 shown in FIG. In FIG. 2, the filling constant pressure on-off valve 50 and the filling constant pressure on-off valve 50 are of the same type, and each has a cylindrical body 52, 62 having an inner flange 51, 61 at one end, and an inner flange. O-rings (O-rings) 53 and 63 that come into contact with 51 and 61, valve bodies 54 and 64 (hereinafter referred to as “valves 54 and 64”) that move in the bodies 52 and 62, and valves 54 and 64 are O-rings. The compression springs 55, 65 that are pressed against 53, 63, and the compression springs 55, 65 are accommodated in the bodies 52, 62 while applying a predetermined compression force (hereinafter referred to as “preload”) to the compression springs 55, 65. Caps 56 and 66 are provided. And the outer flanges 57 and 67 of the bodies 52 and 62 are installed on the outer surface of the steel pipe 20.

The manner in which the filling constant pressure on-off valve 50 and the injection constant pressure on-off valve 60 are installed in the steel pipe 20 is not limited. For example, the bodies 52 and 62 are fitted or screwed into the filling hole 21 or the injection hole 22. May be combined.
That is, the preloads of the compression spring 55 of the filling constant pressure on / off valve 50 and the compression spring 65 of the injection constant pressure on / off valve 60 are set to the filling pressure (P1) and the injection pressure (P2), respectively, and the filling pressure (P1). Is lower than the injection pressure (P2) (P1 <P2).
Accordingly, when the natural ground improving material is supplied to the steel pipe 20 to increase the internal pressure and the internal pressure reaches the filling pressure (P1), the compression spring 55 contracts first, and the filling constant pressure on-off valve 50 is opened. When the internal pressure further increases and reaches the injection pressure (P2), the compression spring 65 contracts and the injection constant pressure on-off valve 60 is opened.

FIG. 3 is a partial side view in cross section of the upper half for explaining the installation state of the bag body in the injection apparatus 1 shown in FIG. In FIG. 3, the steel pipe 20 is provided with annular bodies 81 and 82 (not shown) having elasticity at predetermined intervals, and the circumferences of the openings 11 and 12 of the bag body 10 overlap the annular bodies 81 and 82. The outer periphery of the overlapped portion is fastened by binding rings 83 and 84. Therefore, even when the sheets (cloth, leather, resin sheet, etc.) forming the bag body 10 are overlapped around the openings 11 and 12 of the bag body 10, the elastic deformation of the annular bodies 81 and 82 is helped. Therefore, the liquid tightness between the bag body 10 and the steel pipe 20 is guaranteed. The annular bodies 81 and 82 may be formed by winding a belt-like body having elasticity.
In addition, as long as the bag body 10 expand | swells by filling with a natural ground improvement material and obstruct | occludes the mouth part 9, a shape, a material, etc. are not limited. In the present invention, “substantially liquid-tight” refers to a material that allows leakage of the natural ground improvement material to such an extent that expansion can be maintained by supplying the natural ground improvement material.

FIG. 4 is a schematic diagram for explaining the operation of the on-off valve in the injection apparatus 1 shown in FIG.
4 (a), the injection device 1 is inserted into the pilot hole 8 formed in the natural ground 7, and the natural ground improvement material supply pipe (illustrated) for supplying the natural ground improvement material to the receiving means 30 of the injection device 1 is shown. Not connected). At this time, since the bag body 10 is folded and hugs the periphery of the steel pipe 20, the outer periphery of the bag body 10 is not pressed against the lower hole, and the injection device 1 is easily inserted into the lower hole 8. Moreover, since the cone cap 40 is installed at the tip of the steel pipe 20, earth and sand do not enter the steel pipe 20.

  In FIG. 4B, when a natural ground improving material (shown as satin in the drawing) is supplied to the steel pipe 20 and the pressure in the pipe reaches the filling pressure (P1), first, the filling constant pressure on-off valve 50 is used. Therefore, the natural ground improving material is discharged into the bag body 10 through the filling hole 21 (indicated by an arrow in the figure), and is filled while the bag body 10 is inflated. Therefore, the mouth 9 of the lower hole 8 is closed (sealed) by the swelled bag body 10.

  In (c) of FIG. 4, the natural ground improving material is continuously supplied to the steel pipe 20, the natural ground improving material is filled in the bag body 10, and the pressure in the bag body 10 (the pressure in the steel pipe 20 is increased). When the injection pressure (P2) reaches the injection pressure (P2), the injection constant pressure on-off valve 60 is opened, so that the natural ground improving material is discharged into the lower hole 8 through the injection hole 22 and then into the lower hole 8. Fills and infiltrates the natural ground 7.

Therefore, the structure of the bag body 10 is simplified, and only the supply of the ground improvement material to the steel pipe 20, that is, the special operation for closing the mouth portion 9 (for example, insertion of cloth (waist), partition wall by caulking seal) The formation of the bag body 10 and the filling of the bag 10 with resin or cement, etc. are not required, so that the mouth 9 can be closed and the ground improvement material can be injected into the natural ground.
The position, size, and quantity of the filling hole 21 and the injection hole 22 are not limited, and the types of the filling constant pressure on-off valve 50 and the injection constant pressure on-off valve 60 are not limited. The steel pipe 20 is not limited to a steel pipe (carbon steel) but includes a stainless pipe (alloy steel), a resin pipe, and the like.

Furthermore, although the above has installed the constant pressure on-off valve in each of the filling hole 21 and the injection hole 22, the present invention is not limited to this.
(Ii) A check valve that discharges the ground improvement material only from the steel pipe 20 toward the bag body 10 is installed in the filling hole 21, and a constant pressure on-off valve is installed in the injection hole 22,
(Iii) Even if the filling hole 21 is only a through hole (the constant pressure on / off valve or check valve is removed) and the constant pressure on / off valve is installed in the injection hole 22, the same operation can be obtained.
(E) Furthermore, when the injection pressure reaches the injection hole 22, it is opened, and once it is opened, a constant pressure release valve that continues to open is installed, and a constant pressure on-off valve or check valve is installed in the filling hole 21. May be.

[Embodiment 2]
FIG. 5: is the side view which made the cross section partially explaining the natural ground improvement material injection | pouring apparatus which concerns on Embodiment 2 of this invention. In FIG. 5, the ground improvement material injection device 2 (hereinafter referred to as “injection device 2”) removes the injection constant pressure on-off valve 60 installed in the injection hole 22 of the injection device 1 in the first embodiment described above. The inside of the steel pipe 20 is opened between the filling hole 21 and the injection hole 22a, and when it reaches an injection pressure (P2) which is a predetermined pressure, the pipe is opened and closed at a pressure lower than the injection pressure (P2). A constant pressure on / off valve 70 (same as the injection constant pressure on / off valve 60) is installed.

  That is, the constant pressure on-off valve 70 for injection includes a cylindrical body 72 having an inner flange 71 at one end, an O-ring (O-ring) 73 that contacts the inner flange 71, and a valve that moves within the body 72. Body 74 (hereinafter referred to as “valve 74”), compression spring 75 that presses the valve 74 against the O-ring 73, and compression while applying a predetermined compression force (hereinafter referred to as “preload”) to the compression spring 75. A cap 76 that houses the spring 75 in the body 72 is provided.

And the outer flange 77 of the body 72 is clamped by a pair of cross-section C-shaped pipes 78 and 79 fitted inside the steel pipe 20. That is, the cross-section C-shaped pipes 78 and 79 are obtained by cutting a steel pipe having an outer diameter larger than the inner diameter of the steel pipe 20 into a predetermined length and slitting it in the circumferential direction. After being inserted into a predetermined position, the diameter is restored by elastic recovery, or is pressed into a predetermined position while sliding on the inner surface of the steel pipe 20, and a pressure of at least about injection pressure (P2) is injected. Even if it is applied to the constant pressure on-off valve 70, it does not move.
Therefore, only by installing one injection constant pressure on-off valve 70, the same operation and effect as the injection device 1 in the first embodiment can be obtained. Therefore, even if the number of injection holes 22a, 22b, and 22c (three places in FIG. 5) is increased, the number of parts does not increase and the part cost does not increase.

In addition, the type of the constant pressure on-off valve 70 for injection and the installation procedure to the steel pipe 20 are not limited. Further, a sealing means may be installed between the injection constant pressure on-off valve 70 and the steel pipe 20.
Further, the outer flange 77 is removed (the outer periphery of the constant pressure on-off valve 70 for injection is cylindrical), and the body 72 is held from both the upstream side and the downstream side, or the body 72 is held only on the downstream side. It may be supported by.

[Embodiment 3]
FIG. 6 is a schematic diagram for explaining a ground improvement material injecting apparatus according to Embodiment 3 of the present invention. In FIG. 6, the natural ground improving material injection device 3 (hereinafter referred to as “injection device 3”) has a plurality of bags.
That is, the steel pipe 20 is provided with a receiving means 30 at one end and a cone cap 40 at the other end, and is provided with a predetermined interval to form bags 10a, 10b, 10c, 10d (hereinafter collectively). May be referred to as “bag 10”).
And the hole 21a, 21b, 21c, 21d for filling is drilled in the position surrounded by the bag bodies 10a, 10b, 10c, 10d of the steel pipe 20, respectively, and the constant pressure on-off valve 50a, 50b for filling there. 50c, 50d are installed.

  Further, an injection hole 22a is formed between the bag body 10a and the bag body 10b, and an injection constant pressure on-off valve 60a is provided there, and the injection hole 22b is provided between the bag body 10b and the bag body 10c. An injection constant pressure on-off valve 60b is provided there, an injection hole 22c is provided between the bag body 10c and the bag body 10d, and an injection constant pressure on-off valve 60c is provided there, and the bag body An injection hole 22d is formed between 10d and the cone cap 40 (same at the other end), and an injection constant pressure on-off valve 60d is provided there.

The constant pressure on-off valves 60a, 60b for injection so that the ground improvement material is discharged from all of the injection holes 22a, 22b, 22c, 22d (hereinafter collectively referred to as “injection holes 22”) substantially simultaneously. The injection pressures (preloads) Pa, Pb, Pc, and Pd at which 60c and 60d (hereinafter may be collectively referred to as "injection constant pressure on-off valve 60") are opened are for injection on the front side (right side in the figure). The higher the constant pressure on / off valve 60, the higher the value.
That is, when the injection device 3 is inserted into a natural ground and the front side is in a low position, the injection holes 22a, 22b, 22c, and 22d (hereinafter referred to as “injection holes”) are caused by the dead weight of the natural ground improvement material supplied into the steel pipe 20. Different values of head pressure (static pressure) ΔPa, ΔPb, ΔPc, ΔPd act on the “injection hole 22” in some cases.

At this time, since there is a relationship of ΔPa>ΔPb>ΔPc> ΔPd, the injection constant pressure on-off valve 60 on the near side is easily opened with the help of the head pressure. Therefore, the injection pressure (preload) is adjusted in order to make it difficult to open the head by the amount corresponding to each head pressure.
That is, the injection pressures of the respective injection constant pressure on-off valves 60 are generally set to Pa = P2 + ΔPa, Pb = P2 + ΔPb, Pc = P2 + ΔPc, and Pd = P2> P1.

Therefore, when the natural ground improving material is supplied to the steel pipe 20 and the internal pressure rises and the internal pressure reaches the filling pressure (P1), first, the filling constant pressure on-off valves 50a, 50b, 50c and 50d are sequentially opened from the front side. The bag bodies 10a, 10b, 10c, and 10d are sequentially expanded from the front side, and the gap between the prepared hole and the steel pipe 20 is separated into a zone, b zone, c zone, and d zone by the plurality of bag bodies 10. Is done.
Then, when the internal pressure further rises and the pressure of the natural ground improving material in the constant pressure on-off valve 60d for injection reaches the injection pressure (P2), it is almost simultaneously in each of the a zone, b zone, c zone and d zone. Natural ground improvement material will be injected.

For this reason, even if it is a long pilot hole (deep hole deep in the back), the natural ground improvement material is uniformly filled over its entire length. Improves.
In addition, although the head pressure is applied to the filling constant pressure on / off valve 50 in the same manner as described above, it is not necessary to expand all the bag bodies 10 at the same time. There is no need to adjust (preload).

  In addition, the above considers only the head pressure (static pressure) when the steel pipe 20 is installed at an inclination, but the pressure transmitted due to the viscosity of the natural ground improvement material, the friction with the inner wall of the steel pipe, etc., drops. In this case, the head pressure (static pressure) is reduced because the injection constant pressure on / off valve 60 on the back side becomes difficult to open (the injection constant pressure on / off valve 60 on the near side becomes easier to open). Similarly, the injection pressure (preload) of each injection constant pressure on-off valve 60 may be adjusted in consideration of the pressure drop.

In addition, the installation quantity of the bag body 10 is not limited to 4 units | sets, It can change suitably according to construction conditions. Moreover, the space | interval of the bag bodies 10 is not limited to an equal thing. Further, the filling holes 21a, 21b, 21c, and 21d are not limited to one for each of the bags 10a, 10b, 10c, and 10d, or the injection holes 22a, 22b, 22c, and 22d are not limited to one for each zone. Each quantity, position, and shape can be appropriately selected.
Further, the types of the filling constant pressure on-off valve 50 and the injection constant pressure on-off valve 60 are not limited, and a check valve, a constant pressure release valve, or the like may be used according to the first embodiment.

[Other Embodiments]
In the first embodiment (see FIGS. 1 to 4), the second embodiment (see FIG. 5), and the third embodiment (see FIG. 6) described above, the filling constant pressure on-off valve 50 or the check valve is provided in the filling hole 21, respectively. Although a valve (not shown) is installed, the present invention is not limited to this, and the filling hole 21 is a through hole (the filling constant pressure on-off valve 50 or the check valve is not installed). Thus, the injection constant pressure on / off valve 60 may be installed in the injection hole 22, or the injection constant pressure on / off valve 70 may be installed downstream of the filling hole 21.

  That is, a means (such as a check valve) for preventing fluctuation of the pressure of the natural ground improving material supplied into the steel pipe 20 is installed upstream of the receiving means 30 or the receiving means 30 (on the natural ground improving material pressure feeding means side). In this case, the ground improvement material once filled in the bag body 10 does not flow backward, and the closing of the mouth portion 9 of the lower hole 8 or the isolation of each zone is maintained.

  Further, in the third embodiment, the pilot hole 8 is isolated into each zone, and the ground improvement material is injected into each zone substantially simultaneously, but the present invention is not limited to this, and the pilot hole 8 may be isolated in each zone, and the ground improvement material may be injected into a predetermined zone ahead of other zones. That is, the injection pressure of the constant pressure on-off valve for injection installed in the zone where the natural ground improvement material is to be injected in advance should be set lower than the injection pressure of the constant pressure on-off valve for injection installed in other zones. . Therefore, if the injection pressure of the constant pressure on-off valve for injection is appropriately set for each zone, the natural ground improving material can be injected into each zone in a desired order.

  The present invention can be widely used as a ground improvement material injecting device for injecting a natural ground improvement material into a natural ground, which is used in a natural ground improvement construction method such as a long edge receiving method and a natural ground tip receiving reinforcement. it can.

The side view which made the upper half the cross section explaining the natural ground improvement material injection | pouring apparatus which concerns on Embodiment 1 of this invention. Sectional drawing explaining the on-off valve in the injection apparatus. The partial side view which made the upper half the cross section explaining the installation condition of the bag body in the injection device 1. The schematic diagram explaining operation | movement of the on-off valve in the injection apparatus. The side view which made the cross section into a part explaining the natural ground improvement material injection | pouring apparatus which concerns on Embodiment 2 of this invention. The schematic diagram explaining the natural ground improvement material injection | pouring apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

1 Ground improvement material injection device 1
2 Ground improvement material injection device 2
3 Ground improvement material injection device 3
DESCRIPTION OF SYMBOLS 7 Ground mountain 8 Lower hole 9 Mouth part 10 Bag body 11 Opening part 12 Opening part 20 Steel pipe 21 Filling hole 22 Injection hole 30 Receiving means 31 Different diameter socket 32 Joint means 40 Cone cap 50 Filling constant pressure on-off valve 51 Inner flange 52 body 53 ring 54 valve 55 compression spring 56 cap 57 outer flange 60 constant pressure on-off valve 61 for injection 61 inner flange 62 body 63 ring 64 valve 65 compression spring 66 cap 67 outer flange 70 constant pressure on-off valve 71 for filling 71 inner flange 72 body 73 ring 74 Valve 74 Body 74 Valve body 75 Compression spring 76 Cap 77 Outer flange 78 Cross section C-shaped pipe 81 Annular body 82 Annular body 83 Binding ring 84 Binding ring Pa Injection pressure Pb Injection pressure Pc Injection pressure Pd Injection pressure ΔPa Head pressure ΔPb head ΔPc head pressure ΔPd head pressure

Claims (5)

A ground improvement material for injecting a ground improvement material into a natural ground having a plurality of substantially liquid-tight bag bodies having flexibility and a steel pipe penetrating the plurality of bag bodies substantially liquid-tightly An injection device,
Receiving means for receiving the ground improvement material at one end of the steel pipe; and a plurality of ground strength improvement materials for filling each of the plurality of bag bodies at the positions of the plurality of bag bodies of the steel pipe. A plurality of injection holes for injecting a natural ground improving material into a natural ground are provided between the filling hole and the plurality of bag bodies of the steel pipe,
When the ground improvement material is supplied to the steel pipe via the receiving means, first, the plurality of bags are filled with the ground improvement material via the plurality of filling holes, and then The natural ground improvement material is injected into the natural ground via the injection hole,
A constant pressure on-off valve for injection that opens when reaching an injection pressure that is a predetermined pressure in each of the plurality of injection holes and closes at a pressure lower than the injection pressure is installed,
The ground improvement material injecting apparatus according to claim 1, wherein the injection pressure increases as the injection constant pressure on / off valve is located closer to one end of the steel pipe among the injection constant pressure on / off valves.   The constant pressure on-off valve for injection which is opened when reaching an injection pressure which is a predetermined pressure and closes at a pressure lower than the injection pressure is installed in the plurality of injection holes. Ground improvement material injection device.   When each of the plurality of filling holes reaches a filling pressure that is lower than an injection pressure of a constant pressure on-off valve for injection installed at a position closest to the other end of the steel pipe, the filling pressure is opened. 3. The ground improvement material injecting apparatus according to claim 1, wherein a constant pressure on-off valve for filling which is closed at a lower pressure is installed.   The ground check material for filling according to claim 1 or 2, wherein a check valve for filling is provided in each of the plurality of filling holes so that the ground check material passes only toward the bag body. Injection device.   A plurality of groups of a pair of annular bodies having elasticity are installed on the outer surface of the steel pipe, and the plurality of groups of a pair of annular bodies around the pair of steel pipe penetration portions through which the steel pipes of the plurality of bags penetrate. 5. The ground improvement material injecting device according to claim 1, wherein the ground material improving material injecting device is bound to the steel pipe via a pipe.

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