JP2017186752A - Method for establishing compaction ground improvement pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for establishing a compaction ground improvement pile capable of discharging a filler material smoothly into a drilled hole and facilitating establishment of the compaction ground improvement pile widened to a prescribed diameter.SOLUTION: A device for establishing a compaction ground improvement pile 101 has a drilling head 22 fitted at a tip of a hollow cylindrical casing pipe 18 that holds a filler material 51. The casing pipe 18 and the drilling head 22 are rotated integrally to penetrate into a soft ground 100 to a prescribed depth, thus forming a drilled hole 52 in the soft ground 100. After drilling the hole, the casing pipe 18 and the drilling head 22 are pulled out while the filler 51 is discharged from the casing pipe 18 into the drilled hole 52, and the penetration and pull-out of the casing pipe and the drilling head is repeated for forming the compaction ground improvement pile that has been widened to a prescribed diameter inside the drilled hole 52. A horizontal cross-section shape of the casing pipe 18 is formed to a roughly elliptical or other non-circular shape.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an apparatus for creating a compacted ground improved pile, and more particularly, to an apparatus for creating a compacted ground improved pile for creating a compacted sand pile for soft ground or the like.

  As a means to improve and strengthen soft ground and liquefied sandy ground, the conventional vibration type construction method (dynamic compaction sand pile construction method) has been improved, making it possible to construct even in urban areas. (Static compaction sand pile construction method) is known (for example, refer to Patent Document 1).

  The construction device of the compaction ground improvement pile using the conventional side compaction pile construction method known by patent document 1 is creating the ground improvement pile by working in order of following (1)-(5). .

(1) First, an excavation head is attached to the end of a casing pipe formed in a hollow tubular shape, the excavation head and the casing pipe are integrally rotated forward to penetrate to a predetermined depth of the soft ground, and an excavation hole is formed in the soft ground. Excavate.
(2) Further, in the process of penetrating into the soft ground, the excavated soil excavated by the excavating head is moved to the outside of the excavating head and is compressed by the peripheral surface of the excavating head and pressed against the excavation hole wall.
(3) When the casing pipe is penetrated to a predetermined depth together with the excavation head, the excavation head and the casing pipe are pulled out to a predetermined height while rotating in reverse. At this time, the filling material such as sand in the casing pipe is discharged into the excavation hole by the internal pressure in the casing pipe.
(4) At the same time, the air that has entered the filling material, such as sand, that has entered from the casing pipe into the drilling hole, enters the casing pipe and the drilling hole wall during rotation of the casing pipe and the drilling head. It is discharged into the atmosphere from the soft ground surface through the excavated soil between.
(5) After pulling out, the casing pipe and the excavation head are reversely rotated and penetrated to a predetermined height, pressure is applied to the filling material discharged into the excavation hole in (3), and the excavation hole is Expand to a predetermined diameter and compact. Then, the penetration and withdrawal of the casing pipe are alternately repeated to create a compacted ground improved pile that is expanded to a predetermined diameter in the excavation hole.

Japanese Patent No. 3650958.

  However, in the conventional compacting ground improvement pile forming apparatus known from Patent Document 1, the horizontal sectional shape of the casing pipe is a perfect circle. Therefore, when the excavation soil enters the gap between the casing pipe and the excavation hole wall during the rotation of the casing pipe and excavation head, the air in the excavation hole passes through the excavation soil and the ground surface. Hard to escape. For this reason, there is a problem that it is difficult to smoothly discharge a predetermined amount of filling material (for example, sand) into the excavation hole, making it difficult to create a compacted ground improvement pile expanded to a predetermined diameter. there were.

Therefore, to provide a compacted ground improved pile generating device that can smoothly discharge a filling material or the like into a drilling hole and easily create a compacted ground improved pile expanded to a predetermined diameter. Therefore, a technical problem to be solved arises, and the present invention aims to solve this problem.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is characterized in that an excavation head is attached to the tip of a hollow cylindrical casing pipe into which filling material is inserted. The casing pipe and the excavation head are integrally rotated to penetrate the soft ground to a predetermined depth, and excavation holes are excavated in the soft ground, and after excavation, the filling material is inserted from the casing pipe into the excavation holes. The casing pipe and the excavation head are repeatedly pulled out and inserted into the excavation hole to create a compacted ground improved pile with a predetermined diameter, and the casing pipe has a horizontal sectional shape. Provided is a device for forming a compacted ground improved pile formed in a non-circular shape.

  According to this configuration, when the excavation head and the casing pipe rotate integrally, the horizontal cross-sectional shape of the casing pipe is non-circular such as an ellipse, whereas the horizontal cross-sectional shape of the excavation hole excavated by the excavation head is It becomes a true circle. Therefore, when the excavation head and the casing pipe rotate together, the cross-sectional shape of the casing pipe and the cross-sectional shape of the excavation hole do not completely coincide with each other, and are always occupied by excavated soil having a gap between them. Thus, a gap that is easy to vent is created, and the gap can be used as a vent. That is, the air vent gap can be used as a gap for releasing the air or the like after applying the internal pressure in the casing pipe and discharging the filling material. Then, while the air or the like used for discharging the filling material or the like is sequentially extracted from the inside of the drilling hole, the filling material or the like can be smoothly discharged into the drilling hole and compacted.

  According to a second aspect of the present invention, there is provided the compacted ground improvement pile according to the first aspect, wherein the casing pipe is integrally provided with a projecting member on the outer peripheral surface of the casing pipe and is rotatably provided. A creation device is provided.

  According to this configuration, the non-circular shape in the horizontal cross-sectional shape of the casing pipe is formed integrally with the protruding member attached to the outer peripheral surface of the casing pipe so as to be integrally rotatable. Therefore, the casing pipe itself does not have to be formed as a non-circular pipe whose horizontal cross-sectional shape is elliptical or the like. Thereby, shaping | molding of a casing pipe becomes easy and it contributes to cost reduction.

  According to a third aspect of the present invention, there is provided the device for forming a compacted ground improvement pile according to the second aspect, wherein at least one of the projecting members is provided.

  According to this configuration, a casing pipe having a non-circular horizontal cross-sectional shape can be easily formed by at least one projecting member provided on the outer peripheral surface of the casing pipe, which contributes to cost reduction.

  According to a fourth aspect of the present invention, in the configuration according to the first, second, or third aspect, the casing pipe is formed by adding a plurality of casing pipes in order to form a single pipe. Each flange has a flange for addition, and the flange of one casing pipe to be connected is provided with a concave portion having a polygonal shape in plan view formed concentrically with the pipe hole. Provided is a compacted ground improvement pile forming device which is provided concentrically with the pipe hole and provided with a convex portion having a polygonal shape in plan view corresponding to the concave portion on the one casing pipe side.

According to this configuration, since a plurality of casing pipes are added to form a single pipe, the pipe can be easily handled. At the same time, when a plurality of casing pipes are added, the flange convex portions of the other casing pipes can be inserted into the concave portions of the flanges of one of the connecting casing pipes. This facilitates the work of replacing the lower end, which is particularly susceptible to breakage. In addition, the concave and convex portions that are inserted and connected to each other are formed in a polygonal shape in plan view, and the flange portion is connected in a state where it is meshed, so that a stronger fixation is possible. Rotational transmission force also increases.

  According to a fifth aspect of the present invention, in the configuration according to the fourth aspect, an auxiliary pipe provided with a nozzle that opens around the excavation head is provided in the casing pipe, and the auxiliary pipe includes the plurality of casings. Pipes are added one after the other at the same time as the pipes are added, and each auxiliary pipe has a connecting socket at the connecting part, and the connecting auxiliary pipe socket has a recess, and the other auxiliary pipe socket. Provides a device for forming a compacted ground improvement pile, wherein a convex portion is provided corresponding to the concave portion of the socket on the one auxiliary pipe side.

  According to this configuration, when a plurality of casing pipes are added to form a single pipe, the auxiliary pipe provided in the casing pipe is also connected to the recess of the socket in the one auxiliary pipe that is connected to the other auxiliary pipe. Can be connected simultaneously by inserting the convex portion of the socket.

  According to a sixth aspect of the present invention, in the configuration according to the fifth aspect, the auxiliary pipe is a pipe through which high-pressure air passes, and two compacted ground improvement piles are provided in the same casing pipe. Providing equipment.

  According to this configuration, among the two auxiliary pipes, for example, by one of the auxiliary pipes, high pressure air is jetted toward the soft ground, loosening the soil in the lower part of the casing pipe, and a drilling blade attached to the drilling head. Since excavation with an excavation blade can be performed while facilitating excavation, the casing pipe can be easily penetrated. In addition, when the excavation head part is clogged with excavated soil or the inside packing material is clogged, the inside of the excavation head is blocked, high pressure air is injected from one pipe, and the excavated soil or The filling material can be loosened and easily removed to effectively discharge the filling material.

  According to the present invention, when the excavation head and the casing pipe are rotated, the rotation is always performed in a state in which a gap that allows easy air venting is formed between the outer peripheral surface of the casing pipe and the inner wall surface of the excavation hole. The pressure (air) after the internal pressure is applied to the air and the medium filling material is discharged is released through the air vent gap, and the medium filling material and the like can be discharged smoothly into the excavation hole. Thereby, the effect that the compacting ground improvement pile expanded to the predetermined diameter can be easily created can be expected.

It is a whole lineblock diagram showing roughly the creation device of the compaction ground improvement pile concerning one example of the present invention. It is a figure which draws and shows typically a part of structure of the casing pipe side of a creation device same as the above partially expanded. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. FIG. 3 is a longitudinal sectional view schematically showing a part of a constituent part on the casing pipe side shown in FIG. 2 in an exploded manner. It is a figure which shows the end surface of the casing pipe shown in FIG. 4, Comprising: (a) is the top view seen from the BB line direction, (b) is the top view seen from the CC line direction. It is a side view which expands and shows the structure of the socket which has connected the auxiliary | assistant pipe shown in FIGS. It is a side view which decomposes | disassembles and shows the socket shown in FIG. It is a figure which shows the end surface of the socket shown in FIG. 7, Comprising: (a) is the top view seen from the DD line direction, (b) is the top view seen from the EE line direction. It is operation | movement explanatory drawing of a creation apparatus same as the above. It is a figure explaining the shape of the hole opened by the excavation head in the creation apparatus same as the above, and the horizontal cross-sectional shape by the side of a casing pipe. It is a figure which shows the process which is implementing the formation of the compacting ground improvement pile using the creation apparatus same as the above, (a) is the figure which shows the state which the excavation head started the penetration to the soft ground, (b ) Is a diagram showing a state in which the penetration of the casing pipe is completed to a predetermined depth, (c) is a diagram showing a state in which the casing pipe is being pulled out together with the excavation head, and (d) is a diagram with the excavation head The figure which shows the state which has re-penetrated the casing pipe to predetermined height, (e) is the figure which shows the state which is pulling out the casing pipe to predetermined height with an excavation head, (f) is a casing pipe with excavation head (G) is the figure which has shown the state which completed the creation of the compaction ground improvement pile. It is a figure explaining the modification of the protrusion member in a creation apparatus same as the above, (a)-(g) has shown the modification which differs, respectively.

  The present invention provides a compacted ground improvement pile creation device that can smoothly produce a compacted ground improved pile that has been expanded to a predetermined diameter by smoothly discharging the filling material, etc., into the excavation hole. In order to achieve the purpose, a drilling head is attached to the tip of a hollow cylindrical casing pipe containing a filling material inside, and the casing pipe and the drilling head are rotated together to form a predetermined soft ground. It penetrates to a depth, and excavates a drill hole having a diameter larger than that of the casing pipe in the soft ground, and after the excavation, while discharging the filling material from the casing pipe into the excavation hole, the casing pipe and the excavation head A device for creating a compacted ground improvement pile having a predetermined diameter expanded in the excavation hole by repeatedly drawing and penetrating, wherein the horizontal cross-sectional shape of the casing pipe is not Obtained by forming the shape was achieved with the construction.

  Hereinafter, a suitable example of a creation device of a compaction ground improvement pile according to an embodiment of the present invention is described in detail with reference to drawings.

  FIG. 1 is an overall configuration diagram schematically showing a compacting ground improving pile forming apparatus according to an embodiment of the present invention. In the figure, a compacting ground improvement pile generating device 10 (hereinafter simply referred to as “creating device 10”) includes a compacted ground improving pile 101 (hereinafter simply referred to as “soil improving pile 101”) in soft ground 100. The creation apparatus 10 includes a ground improvement machine 12 that supports the reader 11. In addition, an air compressor 13, an engine generator 14, a receiver tank 15, and the like are disposed adjacent to the ground improvement machine 12. FIG. 1 shows a state where three ground improvement piles 101 have been created in the soft ground 100.

  The air compressor 13 generates and supplies compressed air used by the ground improvement machine 12, and the generator 14 generates and supplies electric power used by the ground improvement machine 12.

  The leader 11 is suspended from the base machine body 12 a of the ground improvement machine 12 and supported by a back stay 16. The reader 11 is provided with a driving device 17 as a rotational driving means so as to be movable up and down. One end side (upper end side) of the casing pipe 18 that is an excavation shaft is coupled to the lower portion of the drive device 17 via a swivel 17a so as to be capable of forward / reverse drive. In addition, the leader 11 has a hopper 19 for supplying a filling material (for example, sand) 51 (see FIG. 11) accommodated in the casing pipe 18 into the casing pipe 18, and a filling material 51 in the hopper 19. The raising / lowering bucket 20 etc. which supply are attached. The lifting bucket 20 takes in the filling material 51 to be supplied into the casing pipe 18 at a lower position of the leader 11, and then raises the leader 11 and takes in the filling material 51 taken in at the lower position of the leader 11. Can be supplied inside. Further, a depth meter (not shown) for measuring the excavation length of the casing pipe 18, a steadying device 21 for suppressing the deflection of the casing pipe 18, and the like are attached to the reader 11.

  2 is a partially enlarged schematic view of a part of the configuration of the forming apparatus 10 on the casing pipe 18 side, and FIG. 3 is a cross-sectional view taken along line AA in FIG. 4 is a longitudinal sectional view schematically showing a part of the casing pipe 18 shown in FIG. 2 in a disassembled state, and FIG. 5 is a view showing an end face of the casing pipe 18 shown in FIG. ) Is a plan view seen from the BB line direction, and (b) is a plan view seen from the CC line direction.

  As shown in FIGS. 2 to 5, the casing pipe 18 includes an upper casing pipe 18 a and a lower casing pipe 22 a provided on the excavation head 22. The upper casing pipe 18a and the lower casing pipe 22a are connected to each other by additional flanges 23a and 23b, which will be described later, so that the excavation head portion 22b can integrally rotate below the lower casing pipe 22a. Is attached.

  The excavation head 22 includes the lower casing pipe 22 a and the excavation head portion 22 b as described above, and the lower casing pipe 22 a is disposed concentrically with the casing pipe 18. On the other hand, the excavation head portion 22b attached to the lower side of the lower casing pipe 22a is formed in a substantially cylindrical shape, and a plurality of excavation blades 34 are attached to the lower surface side of the excavation head portion 22b. . And if excavation head part 22b rotates integrally with casing pipe 18, excavation blade 34 excavates soft ground 100 in a circle. That is, the horizontal cross-sectional shape of the excavation hole 52 excavated by the excavation head portion 22b is a true circular cross section as shown in FIG.

  As shown in FIGS. 2 and 4, flanges 23 a and 23 b for addition are provided at the connecting portions of the upper casing pipe 18 a and the lower casing pipe 22 a of the excavation head 22 that are connected to each other. .

  As shown in FIG. 5A, the flange 23a provided in the upper casing pipe 18a is formed concentrically with the pipe hole 24 of the upper casing pipe 18a, and is viewed from the direction of the line BB in FIG. A concave portion having an octagonal shape, that is, a concave portion 25 having an octagonal shape in plan view is provided. A plurality (eight in this embodiment) of mounting holes 26a are formed at substantially equal intervals outside the recess 25. On the other hand, the flange 23b provided on the lower casing pipe 22a on the excavation head 22 side is formed concentrically with the pipe hole 24 of the upper casing pipe 18a, as shown in FIG. A convex portion having an octagon when viewed from the CC line direction, that is, a convex portion 27 having an octagon in plan view is provided. Further, a plurality (eight in this embodiment) of mounting holes 26b are formed on the outer side of the convex portion 27 corresponding to the mounting holes 26a of the flange portion 23a.

The flange 23a of the upper casing pipe 18a and the flange 23b of the lower casing pipe 22a connect the flange 23a and the flange 23b to each other when the lower casing pipe 22a on the excavation head 22 side is added to the lower end side of the upper casing pipe 18a. When they are abutted, they are inserted and connected in a state where the convex portion 27 on the flange 23a side is engaged with the concave portion 25 on the flange 23b side, and the mounting hole 26a and the mounting hole 26b correspond to each other. Then, when bolts and nuts (not shown) are commonly attached and fastened to the mounting holes 26a and 26b, the flanges 23a and 23b can be firmly fixed and connected. Further, the flange 23a and the flange 23b thus connected and fixed are connected in a state where the polygonal concave portion 25 and convex portion 27 are engaged with each other, so that the upper casing pipe 18a and the lower casing are connected. The rotation transmission force between the pipe 22a and the upper casing pipe 18a and the excavation head 22 is increased. In addition, each shape of the said recessed part 25 and the convex part 27 should just be polygons, such as a pentagon, a hexagon, etc., so that a meshing connection coupling | bonding may be sufficient even if it is not necessarily a planar view octagon. In many cases, the upper casing pipe 18a and the lower casing pipe 22a of the excavation head 22 are added in order and function as one casing pipe 18 for use. Therefore, in the following description, the upper casing pipe 18a and the lower casing pipe 22a will be described as the casing pipe 18.

  As shown in FIGS. 2 to 5, the casing pipe 18 is provided with two auxiliary pipes 28 and 29 extending in the vertical direction so as to sandwich the inner wall of the pipe hole 24. Of the two auxiliary pipes 28 and 29, the distal end side (lower end side) of one auxiliary pipe 28 extends to the lower end portion of the excavation head portion 22b as shown in FIG. A jet nozzle 30a is attached toward the head. The jet nozzle 30a injects high-pressure air toward the soft ground 100, loosens the soil in the lower part of the casing pipe 18, that is, the lower part of the excavation head 22, and facilitates excavation by the excavation blade 34 attached to the excavation head 22. To play a role. In addition, the front end side of the auxiliary pipe 28 may be branched into a plurality, and the jet nozzle 30a may be attached to each branched front end portion. On the other hand, the distal end side (lower end side) of the auxiliary pipe 29 is extended to the lower end portion of the excavation head portion 22b as shown in FIG. 4, and the jet nozzle 30b is attached to the distal end portion. The auxiliary pipe 29 injects high-speed and high-pressure air from the jet nozzle 30b when the inside of the excavation head is blocked due to clogging of excavation soil around the excavation head 22 or the filling material 51, etc. The excavated soil and the filling material 51 are loosened and removed by the high-speed and high-pressure air, and the filling material 51 is easily discharged from the casing pipe 18 effectively.

  As shown in FIGS. 4 and 5, the auxiliary pipes 28 and 29 are connected to a portion to which the casing pipe 18 is added and connected (in this embodiment, a connecting portion between the upper casing pipe 18a and the lower casing pipe 22a). , Sockets 31 are respectively provided. When the lower casing pipe 22a of the excavation head 22 is added to the lower end side of the upper casing pipe 18a, the sockets 31 and 31 are also connected and connected at the same time.

  As shown in FIGS. 6 to 8, the sockets 31 are female sockets 31 a attached to the lower ends of the auxiliary pipes 28 and 29 in the upper casing pipe 18 a and auxiliary sockets in the lower casing pipe 22 a of the excavation head 22. It is comprised with the male side socket 31b attached to the upper end part of the pipes 28 and 29, respectively. As shown in FIGS. 7 and 8A, the female socket 31a is provided with a concave portion that is circular when viewed from the DD line direction of FIG. 7, that is, a concave portion 32 that is circular in plan view. 7 and FIG. 8B, the male socket 31b has a convex portion 33 that is circular when viewed from the direction of line EE in FIG. 7, that is, a convex portion 33 that is circular in plan view. Is provided.

  When the lower casing pipe 22a of the excavation head 22 is added to the lower end side of the upper casing pipe 18a, the socket 31 is inserted into the recess 32 on the female socket 31a side when the flange 23a and the flange 23b are brought into contact with each other. The convex portion 33 on the side socket 31b side is inserted and connected so that the auxiliary pipes 28 and 29 on the lower casing pipe 22a side and the auxiliary pipes 28 and 29 on the lower casing pipe 22a side of the excavation head 22 are closely connected to each other. It is designed to be connected in series.

  Further, a pair of lower casing pipes 22a located on the outer peripheral surface of the casing pipe 18, that is, immediately above the excavation head portion 22b, is provided with a pair as shown in FIGS. The protruding members 35a and 35b are fixedly provided at positions displaced from each other by 180 degrees. The pair of projecting members 35a and 35b are bilaterally symmetric, and each has a mountain shape in cross section. The horizontal sectional shape of the casing pipe 18 (lower casing pipe 22a) at the position where the pair of projecting members 35a and 35b is provided is substantially elliptical as shown by reference numeral 118 in FIGS. Make a circle. In FIG. 2, the symbol O is the center of the casing pipe 18, the symbol r1 is the radius of the casing pipe 18, the symbol r2 is the radius of the excavation head portion 22b, and the radius r1 of the casing pipe 18 is the excavation head portion. The projection amount S from the center O of each projecting member 35a, 35b is equal to or slightly larger than the radius r2 of the excavation head portion 22b (S ≧ r2), which is smaller than the radius r2 of 22b (r1 <r2). Is set.

  Next, regarding the construction operation of the solid ground improvement pile building device 10 according to the present embodiment shown in FIGS. 1 to 8, in the order of the operation steps (a) to (g) shown in FIG. The operation will be described with reference to the operation schematic diagrams shown in FIGS.

  First, as shown in FIG. 1, the leader 11 is erected at a predetermined construction position by the ground improvement machine 12, and the excavation head 22 attached to the lower end portion of the casing pipe 18 is set at the predetermined construction position. In the casing pipe 18, the filling material 51 put in from the hopper 19 is stored.

  And the drive device 17 in the upper end part of the casing pipe 18 is started, the casing pipe 18 is rotationally driven in the forward direction together with the excavation head 22, and the soft ground 100 of the excavation head 22 is shown in FIG. Begin to penetrate. And in the excavation head part 22b of the excavation head 22, the excavation hole 52 whose horizontal cross-sectional shape is a perfect circle is formed as shown in FIG. The diameter D1 (shown in FIG. 11) of the excavation hole 52 here is, for example, 400 to 520 mm. On the other hand, the horizontal cross-sectional shape of the casing pipe 18 (lower casing pipe 22a) where the pair of projecting members 35a and 35b are provided on the outer peripheral surface is a substantially elliptical shape that is non-circular as shown in FIGS. Forms (118). Therefore, when the casing pipe 18 and the excavation head portion 22b are rotated together, the cross-sectional shape of the excavation hole 52 and the cross-sectional shape of the casing pipe 18 do not completely coincide with each other, as shown in FIGS. In addition, the gap 102 that is always loosened and occupied by the excavated soil having a large number of gaps (hereinafter, this gap is referred to as the “air vent gap 102”) is rotated. .

  Further, as shown in FIG. 11B, when the penetration of the casing pipe 18 reaches a predetermined depth, the penetration is stopped.

  Subsequently, the casing pipe 18 is pulled out while rotating in reverse with the excavation head 22. Simultaneously with the drawing operation, an internal pressure P is applied from above the casing pipe 18 into the pipe hole 24, and the filling material 51 in the casing pipe 18 is discharged into the excavation hole 52. And it pulls out to the predetermined | prescribed height shown to (c) of FIG. In addition, when the excavation head 22 is pulled out together with the casing pipe 18, the air 103 sent as internal pressure from the casing pipe 18 into the excavation hole 52 when the filling material 51 is discharged passes through the air vent gap 102 from the soft ground 100. It is discharged into the atmosphere, and thereby the filling material 51 is smoothly discharged from the casing pipe 18 into the excavation hole 52 by a predetermined amount.

When the casing pipe 18 and the excavation head portion 22b are pulled out to the predetermined height shown in FIG. 11C, the casing pipe 18 is rotated in the reverse direction together with the excavation head portion 22b as shown in FIG. As shown, the casing pipe 18 and the excavation head portion 22b are re-penetrated to a predetermined height. Here, the re-penetration while rotating the casing pipe 18 and the excavation head portion 22b in reverse is because the filling material 51 discharged into the excavation hole 52 is excavated in the normal rotation, so that the excavation is not performed. This is for re-penetrating and compacting the filling material 51. When the casing pipe 18 and the excavation head portion 22b are inserted, the filling material 51 is compressed in the lower direction indicated by the arrow Y in FIG. The ground improved pile 101 having a diameter D2 of about 700 mm is compacted while spreading. Note that the setting of the diameter D2 can be changed by the amount (drawing length) of the filling material 51 to be put in the excavation hole 52.

  When the casing pipe 18 and the excavation head portion 22b are penetrated to a predetermined height shown in FIG. 11 (d), the casing pipe 18 is similarly pulled out while rotating in reverse with the excavation head portion 22b. Simultaneously with the drawing operation, the compressed air 103 is sent into the pipe hole 24 from the upper side of the casing pipe 18 to apply the internal pressure P, and the filling material 51 in the casing pipe 18 is discharged into the excavation hole 52. And it pulls out to the predetermined | prescribed height shown to (e) of FIG. Further, when the excavation head portion 22 b is pulled out together with the casing pipe 18, the air 103 sent as internal pressure from the casing pipe 18 into the excavation hole 52 when the filling material 51 is discharged passes through the air vent groove 102 and forms the soft ground 100. At the same time as being released into the atmosphere from the surface, the filling material 51 is smoothly discharged from the casing pipe 18 into the excavation hole 52.

  Further, when the casing pipe 18 and the excavation head portion 22b are pulled out to the predetermined height shown in FIG. 11E, the casing pipe 18 is rotated in the reverse direction together with the excavation head portion 22b, as shown in FIG. As shown, the casing pipe 18 and the excavation head portion 22b are re-penetrated to a predetermined height. When the casing pipe 18 and the excavation head portion 22b are inserted, the filling material 51 is compressed in the lower direction indicated by the arrow Y at the same time as described with reference to FIG. The ground improvement pile 101 having a diameter D2 of about 700 mm is compacted while being spread in the horizontal direction shown in the figure, and is added onto the ground improvement pile 11 created in FIG.

  Subsequently, when the casing pipe 18 and the excavation head 22 are penetrated to a predetermined height shown in FIG. 11 (f), the casing pipe 18 is rotated in the reverse direction together with the excavation head portion 22b as shown in FIG. 11 (g). It is completed when it is pulled out to the ground surface again. In this example, after (f) in FIG. 11, the case where the filling material 51 is ended simply by placing the filling material 51 in the excavation hole 52 in (g) is described. ) May be repeated to create the ground improvement pile 101 up to the surface of the soft ground 100.

  Therefore, according to the compacted ground improvement pile forming apparatus 10 according to the present embodiment, a pair of projecting members 35a and 35b are provided on the outer peripheral surface of the casing pipe 18, and the casing pipe 18 provided with the projecting members 35a and 35b. Whereas the horizontal cross-sectional shape at the location is substantially oval (non-circular), the horizontal cross-sectional shape of the excavation hole 52 excavated with a diameter larger than that of the casing pipe 18 by the excavation head 22 is a perfect circle, and the casing is always A gap (air venting gap 102) is provided between the pipe 18 and the inner surface of the excavation height 52. Therefore, when the filling material 51 is discharged by applying the internal pressure P in the casing pipe 18, the air 103 discharged from the casing pipe 18 into the excavation hole 52 is released into the atmosphere using the air gap 102. Therefore, it is possible to create the ground improvement pile 101 that is firmly compacted by smoothly discharging the filling material 51 into the excavation hole 52.

In the above embodiment, a substantially elliptical shape (non-circular shape) on the casing pipe 18 (lower casing pipe 22a) side is formed by attaching a pair of projecting members 35a and 35b to the outer peripheral surface of the casing pipe 18. However, any one of the protruding members 35a and 35b (
35a or 35b) may be provided. Further, the horizontal cross-sectional shape of the casing pipe 18 (the upper casing pipe 18a and / or the lower casing pipe 22a) itself may be formed in an elliptical shape without providing the protruding members 35a and 35b. Furthermore, the substantially elliptical shape on the casing pipe 18 side may be a non-circular shape such as a quadrangle.

  Further, as a modified example of the protruding member 35 provided on the outer peripheral surface of the casing pipe 18 (lower casing pipe 22a), a structure as shown in FIG. That is, (a) of the figure shows a case where only one protruding member 35 is provided on the outer peripheral surface of the casing pipe 18, (b) shows a case where three are provided at equal intervals on the outer peripheral surface, and (c) shows (a). When a pair of projecting members 35 that are wider in the circumferential direction than the projecting members 35 shown in (b) are provided symmetrically in the left-right direction, (d) shows that the projecting members 35 that are wider in the circumferential direction are equally spaced on the outer circumferential surface. When (e) is provided with a pair of narrow plate-like projecting members 35 symmetrically, (f) is provided with three narrow plate-like projecting members 35 at equal intervals. (G) is a case where three narrow plate-like projecting members 35 are provided at equal intervals. This modification is just an example.

  Therefore, the present invention can be further modified in various ways without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

DESCRIPTION OF SYMBOLS 10 Compaction ground improvement pile creation apparatus 11 Leader 12 Ground improvement machine 12a Base machine main body 13 Air compressor 14 Motor generator 15 Receiver tank 16 Back stay 17 Drive device 18 Casing pipe 18a Upper casing pipe 19 Hopper 20 Lifting bucket 21 Swing Stop device 22 Excavation head 22a Lower casing pipe 22b Excavation head portion 23a Upper casing pipe side flange 23b Lower casing pipe side flange 24 Pipe hole 25 Recess 26a, 26b Mounting hole 27 Protrusion 28 Auxiliary pipe 29 Auxiliary pipe 30a, 30b Jet nozzle 31 Socket 31a Female socket 31b Male socket 32 Recess 33 Protrusion 34 Excavation blades 35a, 35b Projecting member 51 Filling material 52 Excavation hole 100 Soft ground 101 Compacted ground improved pile 102 Gap (Air vent groove)
103 Air (pressure)
118 Oval shape P on casing pipe side Internal pressure D1 Diameter of excavation hole D2 Diameter of ground improvement pile r1 Radius of casing pipe r2 Radius of excavation head S Projection amount of projecting member

Claims (6)

An excavation head is attached to the tip of a hollow cylindrical casing pipe containing the filling material inside, and the casing pipe and the excavation head are rotated together to penetrate to a predetermined depth of the soft ground, and the soft ground The excavation hole is excavated, and after excavation, the casing pipe and excavation head are repeatedly pulled out and penetrated while the filling material is discharged from the casing pipe into the excavation hole, and the excavation hole expands to a predetermined diameter. A device for creating a compacted ground improved pile,
An apparatus for forming a compacted ground improvement pile, wherein the casing pipe has a non-circular horizontal cross-sectional shape.   2. The compacting ground improvement pile forming apparatus according to claim 1, wherein the casing pipe is integrally provided with a projecting member on the outer peripheral surface of the casing pipe so as to be rotatable.   The device for forming a compacted ground improvement pile according to claim 2, wherein at least one projecting member is provided.   The casing pipe is formed by sequentially adding a plurality of casing pipes to form a single pipe, and each casing pipe has a flange for addition at the connecting portion of each casing pipe, and the flange of one casing pipe to be connected Is provided with a recess having a polygonal shape in plan view formed concentrically with the pipe hole, the flange of the other casing pipe is disposed concentrically with the pipe hole, and the recess on the side of the one casing pipe is provided. The forming device for a compacted ground improvement pile according to claim 1, 2 or 3, wherein a convex portion having a polygonal shape in plan view is provided correspondingly.   In the casing pipe, an auxiliary pipe provided with a nozzle that opens around the excavation head is provided, and the auxiliary pipe is sequentially added simultaneously with the addition of the plurality of casing pipes. Each of the auxiliary pipe sockets to be connected has a recess, and the other auxiliary pipe socket corresponds to the recess of the socket on the one auxiliary pipe side. The device for forming a compacted ground improved pile according to claim 4, wherein a convex portion is provided.   The said auxiliary | assistant pipe is a pipe which lets high pressure air pass, and is each provided in the same casing pipe 2 each, The creation apparatus of the compaction ground improvement pile according to claim 5 characterized by the above-mentioned.

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