KR101546497B1 - Ground reinforcement method - Google Patents

Abstract

The present invention relates to a ground reinforcement method for reinforcing the ground by forming underground bulbs in the soft ground and, more specifically, to a ground reinforcement method for improving reinforcement strength by forming ground bulbs not in an irregular shape but in a vertical shape in a grouting step and simultaneously injecting grout materials and pulling out an insertion steel pipe to prevent the insertion steel pipe from being blocked by the grout materials in the grouting step. To achieve the purpose, the ground reinforcement method according to the present invention comprises: A) a step of excavating and preparing a burial hole on the soft ground; B) a step of inserting and installing, into the burial hole, an insertion steel pipe including a fore-end device having multiple inlets arranged in multiple rows; and C) a grouting step of forming vertical ground bulbs by pulling out the insertion steel pipe gradually from the burial hole while simultaneously inserting grout materials into the burial hole using the insertion steel pipe.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground reinforcement method for simultaneously injecting grout materials and drawing drawn steel pipes.

The present invention relates to a ground reinforcement method for reinforcing a ground by forming an underground bulb in a soft ground, and more particularly, to a method for reinforcing a ground by forming an underground bulb in a vertical shape instead of a concave- The present invention relates to a ground reinforcement method for simultaneously injecting a grout material and drawing an injection steel pipe so as to prevent an injection steel pipe from being obstructed by a grout material.

Generally, the ground reinforcement method is completed by excavating a buried hole having a predetermined depth in a soft ground to be reinforced, injecting a grooved material into the buried hole, and curing the buried hole.

In such a ground reinforcement method, the grout material is injected and injected through the side and lower injection holes formed at the end of the injected steel pipe to fill the buried hole. In this case, when the grout material is injected and hardened, the injected steel pipe can not be taken out of the buried hole , After a predetermined amount of grout material is injected, the injected steel pipe is pulled out at a predetermined height and pulled out, and then the grout material is injected again to fix it repeatedly.

As a conventional technique related to the ground reinforcement method of the above-mentioned method, Korean Patent Laid-Open No. 10-2012-0075444 (2012.07.06.) "Method of forming an underground bulb by high-pressure grouting" However,

In the prior art, after a buried hole is drilled in a ground, an injection steel pipe is inserted to a lower portion of the buried hole, the upper opening of the buried hole is closed,

A step of grouting by injecting a grout material; a step of drawing the injection steel pipe at a predetermined height (one step; approximately 30 cm to 50 cm) by grouting; and a step of grouting by injecting the grout material again after the drawing, do.

In the prior art, the injection of the grout material is stopped when the injected steel pipe is pulled out, and then the injection of the grout material is repeatedly performed when the drawing is completed, thereby reinforcing the soft ground.

According to the conventional technique, an underground bulb corresponding to one step height is formed each time a series of operations (grout reinjection-grout reinjection stop) is performed. Whenever a step-by-step underground bulb is formed, The injection is temporarily stopped, so that the injection port of the injected steel pipe is often clogged with the grout material,

In particular, since the outer circumferential surface of the underground bulb formed along the buried hole is formed in a shape similar to the concavo-convex shape (the shape in which the underground bulges S1 in the shape of tube are continuously laminated, see Fig. 1) There is a problem that the strength reinforcement of the soft ground is not sufficient due to the difference in the thickness of the underground bulb.

That is, the conventional art has a problem that the strength of the underground bulb is not constant, the strength is weak, there is no reinforcement, resistance to tensile and bending is weak, the consumption of the grout material is large, and the construction time is very long.

Accordingly, the present invention has been made to solve the above-mentioned problems,

And a grouting step of simultaneously injecting the grout material and drawing the injected steel pipe so as to shorten the construction time and reduce the consumption amount of the grout material by uniformly forming the thickness of the underground bulb, And to provide a reinforcement method.

In addition, the present invention is characterized in that, when an underground bulb is formed, the outer circumferential surface of the underground bulb is not cured in a concavo-convex shape, and the injection holes are increased in diameter and number from the upper side to the lower side along the longitudinal direction so that a vertical underground bulb can be formed And an object of the present invention is to provide a ground reinforcement method using one end device.

In addition, the present invention provides a method of reducing the time required for constructing a plurality of underground bulbs while preventing the problem of clogging of the injected steel pipe by continuously injecting the grout material, And a grout material injecting device for injecting the grout material to the other immediately injected steel pipe immediately after the first injection of the grout material is completed to the injected steel pipe of the second molten steel pipe.

It is another object of the present invention to provide a ground reinforcement method using an injection distributor in which an individual regulator is provided on a mounting portion to which feed pipes of injected steel pipes are connected so as to facilitate the injection and distribution of the grout material through the grout re-injection device.

In order to accomplish the above object, a ground reinforcement method according to the present invention comprises:

A) excavating and preparing a buried hole in a soft ground;

B) inserting and installing an injected steel pipe having a plurality of injection ports arranged in a row in the inserting hole; And

C) a grouting step of injecting the grout material into the buried hole using the injected steel pipe and gradually drawing the injected steel pipe from the buried hole to form a vertical underground bulb; .

In the ground reinforcement method according to the present invention,

The end-

And the injection ports of the lower row are formed so as to have a larger diameter and a larger number than the injection ports of the adjacent upper row.

In the ground reinforcement method according to the present invention,

A plurality of buried holes are drilled in the soft ground through the step A)

In step B), an injection steel pipe is installed only in a part of the buried holes of the plurality of buried holes, and the step (C) is performed on the injected steel pipe of some of the installed injection steel pipes. ,

The installed injection steel pipes are all connected through a single grout reinjector,

The grout re-injection apparatus is characterized in that after the first injection of the grout material to a part of the injection steel pipes is completed, the grout material is injected into the remaining injection pipes continuously in the standby state.

Further, in the ground reinforcement method according to the present invention

Wherein the grout reinjection apparatus comprises an injection distributor for causing secondary injection of the grout material to be carried out successively after the first injection of the grout material,

The injection dispenser is characterized in that each of the mounting portions to which the supply pipes of the injection steel pipes are connected is provided with an individual regulator.

 Since the ground reinforcement method according to the present invention simultaneously injects the grout material and draws the injected steel pipe, the construction time can be shortened. In particular, since the vertical ground electrode having uniform thickness in the longitudinal direction is formed, It is possible to reduce the consumption amount of the grout material and to prevent the injection steel pipe from being closed due to the injection stop of the grout material during the installation.

Also, the ground reinforcement method of the present invention uses a pointing device having injection ports whose number and diameter increase from the upper side to the lower side along the longitudinal direction, thereby preventing the grout material from being pushed in a specific direction during the grout reinjection, It is very advantageous to construct a vertical underground bulb which is uniformly injected with grout ash.

In the ground reinforcement method according to the present invention, the grout material is firstly injected into some of the injected steel pipes installed in the plurality of buried holes, and then the grout material is injected into the other remaining injected steel pipes Since the grouting step can be continuously carried out by introducing the grout re-injection device, it is possible to reduce the grouting preparation time and to prevent the injection steel pipe from becoming blocked.

Furthermore, since the grout reinforcement method according to the present invention controls the injection and distribution of the grout material through the injection / dispenser equipped with the individual regulator, the grouting step can be continuously and smoothly performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view schematically showing an underground bulb formed by a conventional ground reinforcement method;
2 is a flow chart for explaining a ground reinforcement method according to the present invention.
FIGS. 3 to 5 are views schematically showing steps of the ground reinforcement method according to the present invention.
6 is a view schematically showing an underground bulb formed by the fat-strengthening method according to the present invention;
FIG. 7 is an exemplary view for explaining a process in which a grout material is injected into a plurality of buried holes in the ground reinforcement method according to the present invention; FIG.
8 and 9 are enlarged cross-sectional views for explaining a coupling structure of an injection steel pipe and a distal end device according to the present invention.

While the present invention has been described in connection with certain embodiments, it is obvious that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the drawings, the same reference numerals are used for the same reference numerals, and in particular, the numerals of the tens and the digits of the digits, the digits of the tens, the digits of the digits and the alphabets are the same, Members referred to by reference numerals can be identified as members corresponding to these standards.

In the drawings, the components are expressed by exaggeratingly larger (or thicker) or smaller (or thinner) in size or thickness in consideration of the convenience of understanding, etc. However, It should not be.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

 In the present application, the term " comprising " or " consisting of ", or the like, refers to the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

It is to be understood that the first to second aspects described in the present specification are merely referred to in order to distinguish between different components and are not limited to the order in which they are manufactured, It may not match.

In describing the ground reinforcement method according to the present invention, when an unambiguous approximate direction reference is referred to for convenience, referring to FIG. 3, the direction in which the gravitational force is applied is determined as the downward direction, Unless otherwise specified in the description and claims of the relevant invention, directions are specified in accordance with this standard.

Hereinafter, a ground reinforcement method for simultaneously injecting a grout material and drawing an injection steel pipe according to the present invention will be described with reference to the accompanying drawings.

2 to 6, the ground reinforcement method according to the present invention includes:

A) excavating and preparing a burial hole (H) in a soft ground (S100);

B) a step S200 of inserting and installing an injected steel pipe 10 provided with a tip device 11 in which a plurality of injection ports 12 are arranged in the buried hole H; And

C) The grout material C is injected into the buried hole H by using the injected steel pipe 10 and the injected steel pipe 10 is gradually pulled out from the buried hole H, A grouting step (S300) of forming a groove (S); .

In the step A), the embedding hole H is excavated up to a predetermined depth in the vertical direction of the soft ground G by using a punching device (not shown).

The boring device may be a drill bit such as a ring bit. Although not shown in the drawings, the first buried hole having a large diameter, which can be filled with mortar or stonewrite, is first drilled according to the drilling depth, The second buried hole having a small diameter for injecting the first buried hole can be excavated subsequently to the first buried hole.

In this case, a casing (not shown) may be further provided in the first buried hole, and a gap between the casing and the first buried hole is sealed with a cement mixture or the like.

A) When the excavation of the buried hole H is completed in step S100, B) In step S200, the inserted steel pipe 10 is inserted into the buried hole H and installed.

This injection steel pipe 10 is a pipe type having a hollow portion penetrating along the longitudinal direction. The injection pipe 10 has a plurality of injection holes 12 arranged on the outer side thereof and a distal end device 11 having a lower end opened. As shown in Fig.

Although not shown in the drawing, a packer for sealing the buried hole H may be further provided at a connection portion between the distal end device 11 and the injected steel pipe 10.

At this time, the injection ports 12 of the tip unit 11 are arranged such that the grouting material C is injected in such a form as to be widened from the upper part to the lower part of the embedding hole H, The diameter is increased.

That is, as shown in FIG. 4, the injection ports of the lower row are relatively increased in diameter and number than the injection ports of the adjacent upper row.

The reason for introducing the injection ports 12 whose numbers and diameters increase toward the lower side is that the grout material C is injected so that when the injected steel pipe 10 is drawn at the same time, , The grout material (C) is prevented from being tilted in a specific direction and is uniformly filled, so that the underground bulb is formed into a straight type vertical underground bulb (S).

In addition, the step (B) S200 may further include the step of installing a reinforcing material such as a reinforcing steel along the periphery of the injection steel pipe 10 installed in the buried hole H in accordance with the ground reinforcement purpose.

The withdrawal jack 20 is installed in the injected steel pipe 10 exposed above the buried hole H after the injection and the fixing of the injected steel pipe 10 are completed in the step B) And the supply pipe 32 is connected to the upper opening of the grout re-injection device 30.

When the connection with the grout reinjection apparatus 30 is completed, the grout reinjection apparatus 30 is operated to inject the grout material C at step S300.

The grout material (C) used in the present invention is a grout material (C) containing blast furnace slag cement.

The reason for using the grout material (C) containing the blast furnace slag cement is that when the ground is reinforced to install a harbor facility on the beach, the calcium aluminate (C ₃ A, ₃ CaO 2 O 2 O ₃ ) and calcium hydroxide (Ca (OH) ₂ ), a hydration product of cement, react with sulfate and the like in seawater to generate ettringite, which is an expansive crystal, to prevent cement hydrate from being destroyed.

Also, the grout material (C) can prevent the grout material (C) from being lost by the underground water or the like of the ground by mixing the flameproof admixture.

In this case, as in the case of the conventional ground reinforcement method, step-by-step injection for stopping the injection after the injection of the grout material (C), drawing the injected steel pipe 10 by a predetermined height and injecting the grout material not,

The grout material C is injected into the embedding hole H and the injected steel pipe 10 is pulled out adheringly in the embedding hole H by using the drawing jack 20. [

That is, when the grout material C is started to be injected, the grout material C is continuously injected while slowly drawing the injected steel pipe 10 at a predetermined speed from the buried hole H without stopping the injection.

Accordingly, since the injected steel pipe 10 is lifted at a constant speed and is continuously injected from the drawn space while being filled with the grout material C, the vertical ground electrode S can be formed.

The present invention can prevent clogging of the grout material (C) because the grout material (C) is continuously injected in step (S300) without stopping,

When the vertical underground bulb S is formed in this manner, the outer circumferential surface of the underground bulb is formed into a uniform cylindrical shape, so that waste and loss of the grout material C are eliminated, and the underground bulb is formed more firmly.

It is preferable that the grout re-injecting apparatus 30 has a high-pressure injection capability of 100 bar or more in the step C), and the injection pressure and the drawing speed are changed according to the diameter of the buried hole H and the softening degree of the ground G So that it is properly adjusted.

On the other hand, when reinforcing the soft ground G, it is common to excavate a plurality of buried holes H over the entire area to be filled and sequentially inject the grout material C into all the buried holes H, The ground reinforcement method may be carried out by performing the above B) and C) step S200 (S300) on one or a plurality (usually three) of the buried holes H, And then the grout material C is injected repeatedly.

Therefore, the interval for reinstalling the injected steel pipe 10 or the like from one point to another point is prolonged, and the flow of the grout material C is interrupted, so that the preparation time is long and the clogging of the grout material C frequently occurs There is a problem that occurs.

Accordingly, in the present invention, a plurality of buried holes H are excavated in the soft ground G through step A100,

The injected steel pipe 10 is installed only in a part of the buried holes H of the plurality of buried holes H in step B 200 and then the injected steel pipe 10 is inserted into a part of the injected steel pipe 10 (C) step (S300) is performed for the remaining injected steel pipe (10B) in the standby state,

The installed injected steel pipes 10 are all connected through a single grout reinjecting device 30,

The grout reinjection apparatus 30 completes the first injection of the grout material C to a portion of the injected steel pipe 10A and then continuously injects the grout material C into the remaining injected steel pipe 10B in the standby state And the second injection is performed.

More specifically, as shown in Fig. 7, the injection of the grout material C into the three buried holes H will be described as an example.

First, a plurality of buried holes H are excavated in the soft ground G to be reinforced in step S100. Here, the excavation of a plurality of buried holes H means that the buried holes are not entirely excavated all over the entire area of the soft ground G. At the same time, the number of buried holes to be filled with the grout material C Means that additional burial holes are concurrently operated simultaneously during B) step S200 and C) step S300 after drilling the buried hole first.

Accordingly, as shown in the drawing, a total of six buried holes H are first drilled, all the filled steel pipes 10 are installed in each of the buried holes H, and then the filled steel pipes 10 are filled with one grout material To the device (30).

(C) In the step (S300), the grout material C is primarily injected only into the injected steel pipe 10A installed in the three buried holes H1, and the grout material C is injected into the other three buried holes H2 (C) Step S300 is not performed for the inserted injection pipe 10B.

When C) step S300 is completed with respect to the first three buried holes H1, C) step S300 is performed secondarily with respect to the remaining three buried holes H2 immediately after that, and in the meantime, The grouting material is injected and the injected steel pipe 10A drawn out from the buried hole is installed in the other buried holes to prepare the next step C300.

Therefore, if C) step S300 is repeatedly carried out for every buried holes H by utilizing the grout reinjection apparatus 30 as described above, the preparation of A) and B) step S100 (S200) It is possible to shorten the time and to prevent the grout material (C) from being injected into the grout re-injecting device (30) to prevent clogging of the grout material (C).

The grout material injecting device 30 is connected to the grout material C so that the injection of the grout material C can be continuously and distributively injected into the plurality of injected steel pipes 10 through the grout re- And an injection dispenser (31) for causing secondary injection of the grout material (C) successively after the first injection of the grout material (C)

The injector-dispenser 31 is provided with an individual regulator 33 on each of the mounting portions to which the supply pipes 32 of the injected steel pipes 10 are connected.

The individual regulator 33 individually opens and closes the connecting portions of the injection distributor 31 and the supply pipes 32 so that the grout material C can be selectively supplied to only a part of the supply pipes 32, The individual regulator 33 is provided inside the injection dispenser 31 as shown in FIG.

That is, as shown in the figure, when the two supply pipes 32A and 32B are connected to the distributor 31,

The second individual regulator 33B closes the second supply pipe 32B in a state where the first individual regulator 33A is opened and the grout material C is injected through the first supply pipe 32A,

When the primary injection is completed, the first individual regulator 33A is closed and the second individual regulator 33B is opened, so that the direction of injection of the grout material C is changed.

At this time, when the individual regulator is provided outside the injection dispenser, that is, in the direction of the supply pipe, there is a great risk that the grout material C remaining on the protruded portion becomes stagnant and clogged.

In the present invention, however, since the individual regulators 33 are provided inside the injection distributor 31, when the individual regulator 33A is closed after the first injection of the grout material is completed, all of the grout material C in the injection distributor 31 And is flow-fed in the direction of the other individual regulator 33B which is open, thus preventing the above-described occlusion.

8 and 9, the injected steel pipe 10 and the distal end device 11 are provided with flanges 13 and 14 for mutual coupling, respectively, and the coupling holes 13a The inserted steel pipe 10 and the distal end device 11 are coupled to each other in such a manner that a bolt is inserted into the threaded portion 14a and the nut is fastened to the threaded portion.

However, if the grout material C is cured by putting the grout material (C) on the nut (or bolt) during the step S300, if the tip apparatus 11 needs to be replaced for reinforcement of another ground, the cured grout material C The bolt can not be easily loosened, so that the replacement operation of the tip apparatus 11 becomes very difficult.

If the bolts are simply screwed together without using a nut in order to prevent the above-described problems, there is a risk that the bolts are loosened by vibration or the like to separate the inserted steel pipe 10 and the distal end device 11 from each other.

Accordingly, the present invention solves the above-mentioned problem by introducing the coupling means 40 in which the threaded portion of the bolt is not exposed to the outside and the fixing method similar to the nut is used.

The coupling means (40) of the present invention

A first engaging hole 13a formed so as to be closed at an upper side of the upper flange 13 of the distal end device 11,

A second fitting hole 14a formed vertically through the lower flange 14 of the injected steel pipe 10,

A screw portion 41A penetrating through the second fitting hole 14a to be screwed to the first fitting hole 13a and a tightening portion 41B connected to an upper end portion of the threaded portion 41A, A tip end portion 41C whose thickness is narrowed at the end of the coupling member 41A, a coupling member 41 in which a coupling groove 41a is formed,

An elastic member 42 which is fixed on the first engagement hole 13a and has a circular twist portion 42A in which an elastic force is exerted in a direction to be inserted into the engagement groove 41a of the threaded portion 41A, ,

And a separating member 43 provided around the first engaging hole 13a and pressing the pressing portion 42a of the elastic member 42 to open the circular twist portion 42A.

First, the fastening member 41 is a member that can be screwed by rotating the throttle portion 41B using a tool such as a spanner, and is similar to a bolt. However, And a coupling groove 41a is formed on the outer circumferential surface of one side of the connection portion of the threaded portion 41A and the tip end portion 41C.

The elastic member 42 is a kind of torsion spring and exerts an elastic force in a direction in which both side ends of the circular twist portion 42A are widened, that is, a direction in which the circular twist portion 42A is pinched.

One end of the elastic member 42 is fixedly coupled to the attachment groove 13b of the first engagement hole 13a and functions as a fixed portion 42b and the other end of the elastic member 42 communicates with the first engagement hole 13a So that it functions as the pressing portion 42a.

When the distal end device 11 is coupled to the injection steel pipe 10, the threaded portion 41A of the fastening member 41 is inserted into the second fitting hole 14a The screw portion 41B is rotated in the clockwise direction so that the screw portion 41A and the first engagement hole 13a are engaged with each other by a primary screw connection The thread included in the threaded portion 41A and the first engaging hole 13a is omitted, and in this case, the thread of the threaded portion 41A is formed in a section up to the upper portion of the engaging groove 41a).

When the tightening member 41 is firstly screwed to the first engaging hole 13a and then the tightening portion 41B is continuously tightened, the tip end portion 41C is engaged with the hollow portion of the round twisted portion 42A The circular portion 42A is opened to allow the threaded portion 41A to pass through the hollow portion and the engagement groove 41a The circularly curved portion 42A is retracted by the elastic force and is inserted into the engaging groove 41a so that the threaded portion 41A, that is, the engaging member 41 is engaged with the threaded engagement And is fixed by the elastic member 42 to complete the coupling of the injected steel pipe 10 and the distal end device 11. [

The screw portion 41A of the fastening member 41 is restrained by the elastic member 42 and can not move along the fastening holes 13a and 14a so that the fastening member 41 can be rotated counterclockwise Because it does not exist, it has a fixed effect like a snub nuts.

When the distal end device 11 is detached from the injected steel pipe 10 for replacement of the distal end device 11, an operator inserts a tool such as a screwdriver into the separation groove 13c to push the separation member 43, The pressing portion 42a of the threaded portion 42 is pressed and the circular twisted portion 42A is released and released from the fastening groove 41a to release the fastening of the threaded portion 41A.

When the screw portion 41A is rotated in the counterclockwise direction in this state, the screw portion 41A is released from the engagement hole 13a (14a), so that the engagement groove 41a is moved away from the round twist portion 42A, (41) can be separated.

According to the present invention, the joining means 40 having the above-described structure is introduced to maintain the rigid coupling between the injected steel pipe 10 and the distal end device 11 and to secure the grout through the first joining hole 13a, It is possible to prevent the ash C from coming into contact with the fastening member and hardening.

While the present invention has been described with reference to the accompanying drawings, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. And should be construed as falling within the scope of protection of the present invention.

G: ground H, H1, H2: buried ball
C: Grout material S: Underground bulb
10, 10A, 10B: injection steel pipe 11: end cap
12: inlet 13, 14: flange
13a, 14a: coupling hole 13b: installation groove
13c: separation groove
20: Drawing jack
30: grout reinjection device 31: distributor
32, 32A, 32B: supply pipes 33, 33A, 33B: regulator
40: engaging means 41: engaging member
41A: screw portion 41a: fastening groove
41B: tightening part 41C:
42: Elastic member 42A: Circular twist
42a: pressing portion 42b:
43: separating member

Claims (4)

A) excavating and preparing a burial hole (H) in a soft ground (S100);
B) a step S200 of inserting and installing an injected steel pipe 10 provided with a tip device 11 in which a plurality of injection ports 12 are arranged in the buried hole H; And
C) The grout material C is injected into the buried hole H by using the injected steel pipe 10 and the injected steel pipe 10 is gradually pulled out from the buried hole H, A grouting step (S300) of forming a groove (S); , ≪ / RTI >
And coupling means 40 for coupling the injected steel pipe 10 of the step B) and the flanges 13 and 14 of the distal end device 11 to each other,
The coupling means (40)
A first engaging hole 13a formed so as to be closed at an upper side of the upper flange 13 of the distal end device 11,
A second fitting hole 14a formed vertically through the lower flange 14 of the injected steel pipe 10,
A screw portion 41A penetrating through the second fitting hole 14a to be screwed to the first fitting hole 13a and a tightening portion 41B connected to an upper end portion of the threaded portion 41A, A tip end portion 41C whose thickness is narrowed at the end of the coupling member 41A, a coupling member 41 in which a coupling groove 41a is formed,
An elastic member 42 fixed on the first coupling hole 13a and having a circular twist portion 42A in which an elastic force is exerted in a direction to be inserted into the coupling groove 41a of the threaded portion 41A;
And a separating member 43 provided around the first engaging hole 13a and pressing the pressing portion 42a of the elastic member 42 to open the circular twist portion 42A Ground reinforcement method. The method according to claim 1,
The distal end device (11)
Wherein the injection ports of the lower row are formed to have a larger diameter and a larger number than the injection ports of the adjacent upper row. The method according to claim 1,
After a plurality of buried holes H are excavated on the soft ground G through the step A100,
The injected steel pipe 10 is installed only in a part of the buried holes H of the plurality of buried holes H in the step B) ), And the remaining inserted steel pipe 10 is in a standby state,
The installed injection steel pipes 10 are all connected through a single grout material (C) injection device,
The grout material (C) injecting apparatus completes the first injection of the grout material (C) to a part of the injected steel pipe (10A) and then continuously injects the grout material (C) into the remaining injected steel pipe And the second reinforcement is performed. The method of claim 3,
The grout material (C) injecting apparatus includes an injection distributor (31) for performing secondary injection of the grout material (C) successively after the first injection of the grout material (C)
Wherein the injector / distributor (31) is provided with an individual regulator (33) on each of the mounting portions to which the supply pipes (32) of the injected steel pipes (10) are connected.

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