JP2014159691A - Soil improvement machine, soil improvement method and hole opening block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil improvement machine used in columnar soil improvement works capable of preventing a mixture from flowing out from a hole opening or scattering around the hole opening while mixing and agitating excavated soil and a material for column body inside a hole formed in a ground.SOLUTION: A columnar soil improvement machine A includes: a work machine 1; a guide cell 2 attached to the work machine 1 in a vertical direction so as to move in an adjustable manner in the vertical direction; a nozzle 32 which is provided at the front end of the guide cell 2 so as to move in an adjustable manner to output cement milk; a drill head 33; and plural agitation blades 34, 34a, 34b and 34c. The columnar soil improvement machine A further includes: an excavation rod 3 for forming a hole 5 in a ground; and a cap 4 for blocking a hole opening 50 of the hole 5, which is attached to the guide cell 2 to allow the excavation rod 3 to freely rotatably go therethrough, by moving the guide cell 2 in a vertical direction.

Description

  The present invention relates to a ground improvement machine, a ground improvement method, and a hole closing member. More specifically, in ground improvement work in which columnar piles are formed on soft ground, when the excavated soil and column material are mixed and stirred inside the hole formed in the ground, the mixture overflows from the hole or It relates to things that can be prevented from splashing around.

  When constructing a building such as a general house on a soft ground, ground improvement work is being performed to reinforce the ground. The main ground improvement methods include the surface ground improvement method and the columnar ground improvement method. Of these, for example, when the stratum is inclined and a large amount of unsettled settlement is expected in the future, or when it is necessary to pay particular attention to vibration during construction, such as in densely populated houses, the columnar ground improvement method ( Soil cement column method is also used.

  As an example of an apparatus for performing such columnar ground improvement, there is a ground improvement apparatus disclosed in Patent Document 1. This ground improvement device includes a rotating shaft and a flattening member made of a flexible material provided at the tip of the rotating shaft. The flattening member is inserted into a vertical hole formed in the ground, and the flattening member hits the bottom surface of the vertical hole. The flattening member rotates together with the rotating shaft in the contacted state to mix the remaining soil at the bottom of the vertical hole, and by flattening the lower surface of the vertical hole, a columnar body that can prevent a decrease in supporting force is created. It can be done.

JP 2010-65486 A

However, the general columnar ground improvement work using the conventional ground improvement device has the following problems.
That is, in the step of injecting column raw material such as cement milk into the excavated soil inside the vertical hole and moving up and down while rotating the rotating shaft with the stirring blade to make a mixture of excavated soil and column raw material, The mixture overflowed from the hole of the vertical hole, or the mixture was scattered around the hole by the rotation of the stirring blade when the stirring blade came out on the ground.

  As a countermeasure, it is necessary to cure around the hole opening in advance with a synthetic resin sheet that receives the mixture, and this columnar ground improvement is usually concentrated in a certain section and performed in many places. In combination, it takes a lot of time and effort to clean and treat the mixture that has come out of the hole.

(Object of the present invention)
In the columnar ground improvement work in which the columnar pile is formed on the soft ground in the present invention, when the excavated soil and the columnar raw material are mixed and stirred inside the hole formed in the ground, the mixture overflows from the hole mouth, An object of the present invention is to provide a ground improvement machine, a ground improvement method, and a hole closing member capable of preventing scattering around a hole opening.

Means taken by the present invention to solve the above problems are as follows.
(1) The present invention
An underground drilling machine, and a hole closing body for closing the hole of the ground drilled by the underground drilling machine;
With
The underground drilling machine
A guide for holding the guide cell vertically,
A guide cell held so that it can be raised and lowered by the guide;
A drill rod that has a nozzle, a drilling head, and a stirring member on the tip side, and moves up and down along the guide cell;
Have
The hole opening blocker is
A covering portion covering the hole opening;
A through hole formed in the covering portion and through which the drilling rod penetrates;
Have
The hole closing member through which the drilling rod penetrates the through hole of the covering portion is attached to the guide cell so as to be positioned at a lower end portion or a lower position than the lower end portion of the guide cell via a connecting means. ing,
It is a ground improvement machine.

(2) The present invention
It is preferable and recommended that the covering portion of the hole closing member has a shape in which the inside is hollow and the lower surface side is opened.

(3) The present invention
It is preferred and recommended that the aperture closure has an attachment element that is detachable from the connecting means.

(4) The present invention
A step of digging the ground with a drill rod having a nozzle, a drilling head, and a stirring member for forming a columnar raw material to form a hole in which excavated soil remains;
A step of closing the hole of the hole with a hole closing member in a state where the excavation head and the stirring member of the excavation rod are housed in the hole;
A step of taking out columnar raw material from the nozzle inside the hole and infiltrating the excavated soil,
Inside the hole, the excavating rod is rotated and moved up and down to mix and agitate the excavated soil in which the columnar raw material has permeated with the agitating member,
Releasing the closed state of the hole opening of the hole by the hole closing body and extracting the excavating rod from the hole;
Finishing the top end surface of the mixture of the excavated soil and column material inside the hole to a specified height,
Solidifying the mixture to form a columnar pile;
It is a ground improvement method including

(5) The present invention
A step of digging the ground with a drill rod having a nozzle, a drilling head, and a stirring member for forming a columnar raw material to form a hole in which excavated soil remains;
Closing the hole of the hole with a hole closing body in a state where the excavation head of the excavation rod is housed in the hole;
Inside the hole, rotating the excavation rod while taking out the columnar raw material from the nozzle and moving it up and down, and mixing and agitating the excavated soil and the columnar raw material with the stirring member,
Releasing the closed state of the hole opening of the hole by the hole closing body and extracting the excavating rod from the hole;
Finishing the top end surface of the mixture of the excavated soil and column material inside the hole to a specified height,
Solidifying the mixture to form a columnar pile;
It is a ground improvement method including

(6) The present invention
The excavation rod of the underground excavator is rotatably passed through and is arranged at a position lower than the lower end or the lower end of the guide cell of the underground excavator, and the hole hole formed in the ground with the excavation rod, It is to cover by lowering the guide cell,
A covering portion that is hollow inside and open on the lower surface side;
A through hole formed in the covering portion and through which the drilling rod penetrates;
An attachment element that is formed in the covering portion and is attached to the guide cell via a connecting means;
It is a hole opening obstruction | occlusion body which has these.

  The term “columnar raw material” referred to in the present specification and claims is used to include a resin-based solidifying agent in addition to a cement-based solidifying agent such as cement milk.

(Function)
The operation of the ground improvement device according to the present invention will be described.
The ground improvement machine is stopped at a predetermined position on the ground where the ground improvement work is to be performed, and the excavation rod is set vertically at the position where the hole is excavated.
The excavation rod is lowered along the guide cell, and the ground is excavated to a predetermined depth with the excavation rod to form a hole in which excavated soil remains.
In a state where the excavation rod is housed in the hole, the guide cell is lowered, and the hole closing body is covered with the hole opening so as to close the hole opening.

  Inside the hole, the columnar raw material is discharged from the nozzle of the excavation rod and penetrates into the excavation soil. Next, the excavation rod is rotated and moved up and down inside the hole, and the excavated soil and the columnar raw material are mixed and stirred by the stirring member. Alternatively, the drill rod is rotated and moved up and down while discharging the column material from the nozzle of the drill rod inside the hole, and the excavated soil and the column material are mixed and stirred by the stirring member.

  At this time, the amount of the mixture of the excavated soil and the columnar raw material is increased and the pressure is increased in the inside of the hole whose hole is blocked by the hole closing member, because the columnar raw material is injected. However, since the hole opening is closed by the hole opening blocking body, it is possible to prevent the mixture of the excavated soil and the columnar raw material from overflowing to the outside of the hole or scattering around the hole opening. Although the pressure inside the hole rises in this way, the pressure inside the hole fluctuates in parallel with the agitation work as a part of the columnar material infiltrates into the hole wall of the hole with the increased pressure. However, it gradually becomes lower and finally stabilizes at the same level as the pressure outside the hole.

  Then, by raising the guide cell, the closed state of the hole opening by the hole closing body is released, and the excavation rod is raised to remove the excavation rod from the hole. Thereafter, the top end face of the mixture inside the hole is finished to a specified height, and is cured for about one week, for example, to solidify the mixture, thereby forming a cylindrical columnar pile on the ground.

  In addition, as mentioned above, when the column body material infiltrate into the hole wall due to the increased pressure inside the hole, compared with the case where the columnar ground improvement work is performed by the conventional method that does not block the hole opening More columnar materials infiltrate into the hole wall. As a result, when the column body material is solidified, the strength of the columnar pile formed and the hole wall of the hole becomes stronger, the frictional force of the columnar pile against the hole wall becomes larger, the resistance to the settlement of the columnar pile, That is, the supporting force is improved.

  The covering portion of the hole closing body is a shape in which the inside is hollow and the lower surface side is opened, while the hole opening closing body closes the hole opening at the lower end, the internal hollow portion is positioned above the ground, By filling the hollow part of the hole closing body by increasing the amount of the mixture by injecting the column material, it is possible to cope with the construction in which the top end surface of the columnar pile is made higher than the ground.

  If the hole closure body has an attachment element that is detachable from the connecting means, the hole closure body may be removed and placed or stored in an unobstructed place when moving or storing the ground improvement machine. Because it is possible, it is highly convenient.

  The present invention relates to a columnar ground improvement work in which a columnar pile is formed on a soft ground, and when the excavated soil and the columnar raw material are mixed and stirred inside the hole formed in the ground, the mixture overflows from the hole mouth or the hole mouth It is possible to provide a ground improvement machine, a ground improvement method, and a hole opening blocker that can prevent splashing around.

Side view explanatory drawing which cut the cap which shows one Embodiment of the ground improvement machine which concerns on this invention. The expanded explanatory view which carried out the cross section of the cap which shows the tip side of the excavation rod of the ground improvement machine shown in Drawing 1, and the attachment structure of a cap. The perspective explanatory view showing the structure of a cap and a steady rest. (A) is a set state, (b) is an empty digging process, (c) is a lifting process of a drilling rod, (d) is a process of fitting a cap, e) is a mixing and stirring step, (f) is a drawing step of a cap and a drilling rod, and (g) is an explanatory diagram of a finishing step of the top end face. The process of the other columnar ground improvement construction using a ground improvement machine is shown, (a) is a mixing stirring process, (b) is explanatory drawing of the finishing process of a top end surface. Side view explanatory drawing which showed other embodiment of the ground improvement machine which concerns on this invention, and represented the cap with the imaginary line.

Embodiment
The present invention will be described in detail based on the embodiments shown in the drawings.
Please refer to FIG. 1 to FIG.

  The ground improvement machine A includes an underground drilling machine 1, a guide cell 2 that the underground drilling machine 1 has, a drilling rod 3 that has a guide cell 2 that can be moved up and down to form a hole by excavating the ground, and The guide cell 2 has a cap 4 that is a hole closing member that is provided in the lower portion and closes the hole 50 of the hole 5 formed in the ground.

  The underground drilling machine 1 includes a crawler type drilling machine main body 10 and a guide body attached to a front portion of the drilling machine main body 10 through a hydraulic mechanism (reference numeral omitted) such as a hydraulic cylinder 11 in the vertical direction. 12 is provided. The angle of the guide body 12 can be adjusted by a hydraulic mechanism. A guide cell 2 is attached to the guide body 12 so that the guide cell 2 can be adjusted up and down within a certain range along the guide body 12 by a hydraulic cylinder (hidden in the guide cell 2 and not shown). Reference numeral 13 denotes an outrigger.

  The guide cell 2 has a guide portion 20 over almost the entire length on the front side. A drifter 30 having a hydraulic motor as a drive source is attached to the guide unit 20 so as to be movable up and down along the guide unit 20. The drifter 30 holds the excavation rod 3 having a predetermined length, and the excavation rod 3 is suspended in a substantially vertical direction. Reference numeral 21 denotes a winch.

The rod 31 of the excavation rod 3 has an excavation head 33 at the tip. The excavation head 33 includes a bit 330 at the tip of the rod 31, a plurality of rotating members 331 formed at right angles to the rod 31, and a plurality of excavating teeth fixed at regular intervals in the length direction below each rotating member 331. 332.
Further, the rod 31 has a nozzle 32 in the vicinity of the bit 330 for delivering cement milk (cement-based solidifying agent solution) that is a columnar raw material. The nozzle 32 is supplied with cement milk from the mixer plant (not shown) through the inside of the rod 31.

  Agitating blades that are agitating members are formed in four stages at substantially constant intervals in the vertical direction slightly above the excavation head 33 of the rod 31. Each stage of the stirring blades is composed of two stirring blades radially located in the diameter line direction of the rod 31. From the excavation head 33 side, the first stage (bottom stage) is the stirring blades 34 and 34, and the second stage is The stirring blades 34a and 34a, the third stage includes stirring blades 34b and 34b, and the fourth stage (uppermost stage) includes stirring blades 34c and 34c.

  The stirring blades 34, 34a, 34b, 34c are alternately shifted by 90 ° in the axial circumferential direction of the rod 31 at each stage. Each of the lowermost stirring blades 34 is formed so that the blade plate is parallel to the axial direction of the rod 31. The other three stirring blades 34a, 34b, and 34c have the blade plate of the rod 31. It is formed so as to be inclined at a required angle with respect to the axial direction.

The guide cell 2 has a connecting member 22 that extends forward at the lower end. A steady rest 23 is fixed to the tip of the connecting member 22.
The steady rest 23 has a semicircular arc-shaped base body 230 fixed to the connecting member 22 and a semicircular arc-shaped detachable body 231 detachably attached to the base body 230. The base body 230 and the detachable body 231 have a structure in which pins 235 are inserted and fixed in holes (reference numerals omitted) formed in portions where both ends overlap each other (see FIG. 3).

  In the state where the detachable body 231 is fixed to the base body 230, the steady rest 23 has a thick and short cylindrical shape having a through hole 232 in the center. In addition, the rod 31 of the excavation rod 3 first removes the detachable body 231 from the base body 230, puts it in the center of the open part of the base body 230 from the lateral direction, and fixes the detachable body 231 to the base body 230. It can pass through the through hole 232 in a rotatable manner.

  Further, an arcuate hook receiving body 233 extending along the outer peripheral surface is formed on the lower end portion of the outer peripheral surface of the base body 230, and the lower end portion of the outer peripheral surface of the detachable body 231 is similarly formed on the outer peripheral surface. An arcuate hook receiving body 234 is formed to project outward. Pin holes 236 and 237 penetrating in the thickness direction are formed at intermediate portions in the longitudinal direction of the latch receivers 233 and 234. The latch receivers 233 and 234 constitute attachment elements. A cap 4 described below can be detachably attached to the latch receivers 233 and 234.

  As shown in FIG. 3, the cap 4 has a covering portion 40 that is a hollow body including a cylindrical body 41 and a circular top plate 42 fixed to the upper end of the cylindrical body 41. A through hole 43 having the same diameter as the through hole 232 of the steady rest 23 is formed in the central portion of the top plate 42, and further, on the top surface side of the top plate 42, the suspension receivers 233 and 234 of the steady rest 23. The latching bodies 44 and 45 which are attachment elements to latch are formed facing each other.

  The latching bodies 44 and 45 are formed in an arc shape centering on the through-hole 43 with an inverted L-shaped cross section, and are arranged on the diameter line of the top plate 42 with the open side facing each other. It is arranged at the place. Pin holes 440 and 450 penetrating in the thickness direction are formed in the middle portion in the longitudinal direction of the horizontal portions (reference numerals omitted) of the latching bodies 44 and 45. In addition, on the top surface of the top plate 42, annular hanging tools 46 and 47 are fixed at two locations on the diameter line.

  The outer diameter of the cylindrical body 41 of the cap 4 is approximately the same as the inner diameter of the hole 5 so that the hole 50 of the hole 5 formed in the ground can be closed or substantially closed by the columnar ground improvement work. They are formed with substantially the same outer diameter. The length of the cylindrical body 41 is not particularly limited, and is set as appropriate. The cap 4 is fitted to the excavation rod 3 in a state where the rod 31 above the uppermost stirring blade 34 c of the excavation rod 3 is rotatably passed through the through hole 43.

(Function)
Please refer to FIG. 1 to FIG. 3 and FIG. 4 showing the steps of the columnar ground improvement work.

(1) Set (see Fig. 4 (a))
The initial setting of each part of the ground improvement machine A is as follows.
First, the guide cell 2 and the excavation rod 3 are raised (the state shown in FIG. 1), and the uppermost stirring blades 34c are positioned below the top plate 42 of the cap 4, so that the latching receivers 233 and 234 are placed. Then, the retaining bodies 44 and 45 are latched and the cap 4 is attached to the steady rest 23. Normally, there is no problem if the work is performed in this state. However, the pin holes 236 and 440 and the pin holes 237 and 450 are aligned, and the pins 441 and 451 are respectively inserted, so that the cap 4 against the steady rest 23 is obtained. Can also be fixed (see FIG. 2).

  The latching operation is performed by positioning the latching bodies 44 and 45 of the cap 4 at the portion where the latching receivers 233 and 234 are interrupted and turning the cap 4 to slide the latching bodies 44 and 45. This is done by hanging on the receivers 233, 234. Further, when the cap 4 is attached / detached, the attaching / detaching operation can be performed easily and safely by using the winch 21 and hanging the wire hooks (not shown) on the lifting tools 46, 47.

The cap 4 is highly convenient because it can be removed and placed in an appropriate place where it does not get in the way when the ground improvement machine A is moved or stored.
Next, the ground improvement machine A is installed at a predetermined position of the ground where the ground improvement work is performed, and the excavation rod 3 is aligned with the position where the hole 5 is excavated, and the excavation rod 3 is set vertically.

(2) Empty digging process (see FIG. 4B)
The drifter 30 is operated to lower the excavation rod 3 along the guide portion 20 of the guide cell 2, and the excavation rod 3 is rotated to dig the ground to a predetermined depth. Thereby, the circular hole (vertical hole) 5 by the top view which the excavation soil 51 remained inside is formed in the up-down direction. The holes 5 are not limited to the vertical direction, and may be formed in an oblique direction or a lateral direction depending on construction conditions and the like.

(3) Drilling rod lifting step (see FIG. 4 (c))
The excavating rod 3 is raised while the excavating rod 3 is rotated by the drifter 30 so that the uppermost stirring blades 34 c are positioned at a slightly lower height than the hole 50 (the height of the ground) of the hole 5. At this time, a part of the excavated soil 51 may overflow so as to rise from the hole 50. In this case, the excavated soil 51 is removed as necessary, and the entire excavated soil 51 is placed inside the hole 5. You may make it fit.

(4) Cap fitting process (see FIG. 4 (d))
With the nozzle 32 on the front side of the excavation rod 3, the excavation head 33 and the stirring blades 34, 34 a, 34 b, 34 c stored in the hole 5, the guide cell 2 is lowered and the cap 4 is inserted into the hole 5. The opening 50 is fitted into the opening 50 so as to close the opening 50.

(5) Mixing and stirring step (see FIG. 4 (e))
Inside the hole 5, the cement milk, which is a pillar material, is taken out from the nozzle 32 of the excavation rod 3 and penetrates into the excavation soil 51. Further, the excavation rod 3 is rotated and moved up and down inside the hole 5, thereby excavating the soil 51. And the cement milk are mixed and stirred by the stirring blades 34, 34a, 34b, and 34c. Alternatively, the excavating rod 3 is rotated and moved up and down while the cement milk is discharged from the nozzle 32 of the excavating rod 3 inside the hole 5, and the excavated soil 51 and the cement milk are mixed and stirred by each stirring blade.

  At this time, the inside of the hole 5 whose hole 50 is blocked by the cap 4 increases the amount of the excavated soil 51 and the cement milk mixture 52 by injecting cement milk, and the pressure increases. By closing the mouth 50, it is possible to prevent the mixture 52 of the excavated soil 51 and the cement milk from overflowing to the outside of the hole 5 or scattering around the hole 50. In addition, when the pressure inside the hole 5 rises in this way, a part of the cement milk infiltrates into the hole wall of the hole 5 and the infiltrating portion 55 is formed, whereby the pressure inside the hole 5 is increased. Gradually decreases while fluctuating in parallel with the agitation work, and finally stabilizes at the same level as the pressure outside the hole 5.

(6) Cap and excavation rod extraction process (see FIG. 4 (f))
The guide cell 2 is raised, the cap 4 is removed from the hole 50, and the closed state of the hole 50 by the cap 4 is released. Further, the excavation rod 3 is raised while rotating, and the excavation rod 3 is extracted from the hole 5.

(7) Top end face finishing process (see Fig. 4 (g))
After that, the top end face 54 of the mixture 52 inside the hole 5 is finished to a specified height, and is cured for about one week, for example, to solidify the mixture 52, so that a columnar columnar pile (improved pile) is formed under the ground. 53 can be formed.

  In addition, as mentioned above, when cement milk infiltrates into the hole wall of the hole 5 due to an increase in the pressure inside the hole 5, it is compared with the case where the columnar ground improvement work is performed by the conventional method that does not block the hole 50. As a result, more cement milk infiltrates the pore wall. Thereby, when the mixture 52 and the infiltrating portion 55 of the excavated soil 51 and the cement milk are solidified, the strength of the columnar pile 53 formed and the hole wall of the hole 5 becomes stronger, and the columnar pile 53 against the hole wall The frictional force becomes larger, and the yield strength against the settlement of the columnar pile 53, that is, the supporting force is improved.

With reference to FIG. 5, the process of the other columnar ground improvement construction using a ground improvement machine is demonstrated.
As shown in FIG. 5B, this columnar ground improvement work forms a columnar pile 53a having a top end surface 54a higher than the ground.
In the process of columnar ground improvement construction, the same construction as the above construction is performed until the excavation rod pulling up process of FIG.

(Step of closing the hole with a cap (see FIG. 5A))
With the nozzle 32 on the front side of the excavation rod 3, the excavation head 33 and the stirring blades 34, 34 a, 34 b, 34 c stored in the hole 5, the guide cell 2 is lowered and the cap 4 is inserted into the hole 5. The cap 50 is closed so that the lower end of the cap 4 is substantially the same as the height of the hole 50. At this time, even when the excavated soil 51 overflows from the hole 50, the cap 4 may be covered as it is.

(Mixing and stirring process)
In the state shown in FIG. 5A, the drilling rod 3 is rotated and moved up and down while discharging the cement milk from the nozzle 32 of the drilling rod 3 inside the hole 5, so that the excavated soil 51 and the cement milk are mixed with each stirring blade. 34, 34a, 34b, and 34c are mixed and stirred.

  At this time, the inside of the hole 5 whose hole 50 is blocked by the cap 4 is injected with cement milk, so that the amount of the excavated soil 51 and the cement milk mixture 52 increases and protrudes upward from the ground. The inside of the cap 4 is filled. Further, since the hole opening 50 is blocked by the cap 4, it is possible to prevent the mixture 52 of the excavated soil 51 and the cement milk from overflowing to the outside of the hole 5 or scattering around the hole opening 50.

  Then, the guide cell 2 is raised to raise the cap 4, and the closed state of the hole 50 by the cap 4 is released. Further, the excavation rod 3 is raised while rotating, and the excavation rod 3 is extracted from the hole 5. In addition, about cancellation | release of the obstruct | occluded state of the hole 50 by the cap 4, it becomes an operation | movement which removes the cap 4 from the part which protruded from the ground above the mixture 52 in practice.

(Top end surface finishing process (see FIG. 5B))
Thereafter, the top end surface 54a of the mixture 52 inside the hole 5 is finished to a specified height slightly higher than the ground, and is cured for a certain period of time to solidify the mixture 52, whereby a columnar columnar pile 53a is formed on the ground. Can be formed.

With reference to FIG. 6, another embodiment of the ground improvement machine will be described.
The ground improvement machine A can replace the steady rest 23 attached to the guide cell 2 with the holder 35 and the steady rest 36 shown in FIG. An existing holder 35 is used.

  The holder 35 is attached to the lower end portion of the guide cell 2 via the connecting member 24. The holder 35 passes the rod 31 of the excavating rod 3 through a hole (reference number omitted) in the center so as to be rotatable, and is used to change the rod 31 when the excavating rod 3 is lowered downward.

  A steady rest 36 is fixed to the lower part of the holder 35. The steady rest 36 has a through-hole (reference number omitted) through which the rod 31 is rotatably passed at the center, and has an opening 360 on the left and right sides (the back side and the near side in FIG. 6). Reference numeral 37 denotes a scraper. The scraper 37 can penetrate the opening 360 and press against the outer peripheral surface of the rotating rod 31 to scrape mud sand adhering to the outer peripheral surface.

At the lower end portion of the steady rest 36, a latch receiving body 361 is formed on each of the left and right sides. Unlike the latch receivers 233 and 234, each latch receiver 361 is linearly formed in the front-rear direction (left-right direction in FIG. 6), and is also linearly opposed to the cap 4a. The cap 4a can be detachably attached by latching each of the retaining bodies 46 that are present. Further, the cap 4a may be fixed to the steady rest 36 via various fixing means.
In addition, about the effect | action by using the cap 4a, since it is substantially the same as the ground improvement machine A using the said cap 4, description is abbreviate | omitted.

  The terms and expressions used in this specification are merely explanatory and are not limiting at all, and exclude terms and expressions equivalent to the features described in this specification and parts thereof. There is no intention to do. Further, it goes without saying that various modifications are possible within the scope of the technical idea of the present invention.

A Ground improvement machine 1 Underground drilling machine 10 Drilling machine main body 11 Hydraulic cylinder 12 Guide body 13 Outrigger 2 Guide cell 20 Guide part 21 Hoisting machine 22 Connecting member 23 Stabilizer 230 Substrate 231 Detachment body 232 Through hole 233, 234 Hook receiving body 235 Pin 236, 237 Pin hole 3 Drilling rod 30 Drifter 31 Rod 32 Nozzle 33 Drilling head 330 Bit 331 Rotating member 332 Drilling tooth 34, 34a, 34b, 34c Stirring blade 4 Cap 40 Covering part 41 Cylindrical body 42 Top plate 43 Through-hole 44, 45 Latching body 440, 450 Pin hole 441, 451 Pin 46, 47 Lifting tool 5 Hole 50 Hole 51 Excavated soil 52 Mixture 53 Columnar pile 54 Top end face 55 Infiltrating part 24 Connecting member 35 Holder 36 Stabilizer 360 Opening 361 Stopper 3 7 Scraper 46 Suspension body 53a Columnar pile 54a Top end face

Claims (6)

An underground drilling machine, and a hole closing body for closing the hole of the ground drilled by the underground drilling machine;
With
The underground drilling machine
A guide for holding the guide cell vertically,
A guide cell held so that it can be raised and lowered by the guide;
A drill rod that has a nozzle, a drilling head, and a stirring member on the tip side, and moves up and down along the guide cell;
Have
The hole opening blocker is
A covering portion covering the hole opening;
A through hole formed in the covering portion and through which the drilling rod penetrates;
Have
The hole closing member through which the drilling rod penetrates the through hole of the covering portion is attached to the guide cell so as to be positioned at a lower end portion or a lower position than the lower end portion of the guide cell via a connecting means. ing,
Ground improvement machine. The covering portion of the hole closing member has a shape in which the inside is hollow and the lower surface side is opened.
The ground improvement machine of Claim 1. The hole closing member has an attachment element which is detachable from the connection means;
The ground improvement machine of Claim 1 or 2. A step of digging the ground with a drill rod having a nozzle, a drilling head, and a stirring member for forming a columnar raw material to form a hole in which excavated soil remains;
A step of closing the hole of the hole with a hole closing member in a state where the excavation head and the stirring member of the excavation rod are housed in the hole;
A step of taking out columnar raw material from the nozzle inside the hole and infiltrating the excavated soil,
Inside the hole, the excavating rod is rotated and moved up and down to mix and agitate the excavated soil in which the columnar raw material has permeated with the agitating member,
Releasing the closed state of the hole opening of the hole by the hole closing body and extracting the excavating rod from the hole;
Finishing the top end surface of the mixture of the excavated soil and column material inside the hole to a specified height,
Solidifying the mixture to form a columnar pile;
Including ground improvement methods. A step of digging the ground with a drill rod having a nozzle, a drilling head, and a stirring member for forming a columnar raw material to form a hole in which excavated soil remains;
Closing the hole of the hole with a hole closing body in a state where the excavation head of the excavation rod is housed in the hole;
Inside the hole, rotating the excavation rod while taking out the columnar raw material from the nozzle and moving it up and down, and mixing and agitating the excavated soil and the columnar raw material with the stirring member,
Releasing the closed state of the hole opening of the hole by the hole closing body and extracting the excavating rod from the hole;
Finishing the top end surface of the mixture of the excavated soil and column material inside the hole to a specified height,
Solidifying the mixture to form a columnar pile;
Including ground improvement methods. The excavation rod of the underground excavator is rotatably passed through and is arranged at a position lower than the lower end or the lower end of the guide cell of the underground excavator, and the hole hole formed in the ground with the excavation rod, It is to cover by lowering the guide cell,
A covering portion that is hollow inside and open on the lower surface side;
A through hole formed in the covering portion and through which the drilling rod penetrates;
An attachment element that is formed in the covering portion and is attached to the guide cell via a connecting means;
A hole-occlusion body.

Images