JP7057994B2 - Construction method of soil cement pile - Google Patents

Description

The present invention relates to a method for constructing a soil cement pile in a low-flying space.

Conventionally, as one of the construction methods of soil cement piles, for example, as disclosed in Patent Document 1, a method of creating a soil cement column in the ground and then penetrating a steel pipe pile into the soil cement column has been known. Has been done. As a ground improvement device used when constructing a soil cement column, for example, a ground improvement device as disclosed in Patent Document 2 is known.

In the ground improvement device disclosed in Patent Document 2, the upper end of a rotary shaft provided with a solidifying material injection nozzle and a stirring blade near the lower end is installed in a rotary drive device that moves along a reader via a swivel joint. It penetrates into the ground while rotating the rotary shaft with a rotary drive device to create an improved body of soft ground.

Japanese Patent Application Laid-Open No. 2003-206529 Japanese Unexamined Patent Publication No. 07-300853

By adopting the ground improvement device of Patent Document 2 described above, it is possible to create a soil cement column up to a deep layer in the ground. However, when the construction site where the steel pipe soil cement pile is constructed is restricted in the sky, the ground has a structure in which the swivel joint and the rotary drive device are placed above the rotary shaft equipped with the injection nozzle and the stirring blade. In many cases, the improved equipment cannot be accommodated in the limited low-flying space.

In addition, even if the ground improvement device can be accommodated in a limited low-flying space, if it becomes necessary to connect a shaft for addition to the rotating shaft according to the depth of the soil cement column to be created. In addition, it is easy to have a situation where it is not possible to secure a sufficient height space for replenishment work.

The present invention has been made in view of the above problems, and the main object thereof is to provide a soil cement pile having a required depth with high work efficiency even in a low-flying space where the sky is restricted or under narrow conditions. It is to provide a method of constructing soil cement piles that can be constructed.

In order to achieve such an object, the method for constructing a soil cement pile of the present invention was created by rotationally press-fitting the excavation stirring head into the ground while adding a footing rod to the excavation rod provided in the excavation stirring head. A method of constructing a soil cement pile, which is built by adding a core material to a soil cement column. For the chuck mechanism provided in the rotary drive device
The attachment for the core material is attached, the attachment for the rod is attached to the attachment for the core material, the foot rod is gripped from the side by the chuck mechanism via the attachment for the rod, and the excavation stirring head is held. It is characterized in that it is rotationally press-fitted into the ground by the rotary press-fitting device. Further, the rod attachment is provided with a matching groove capable of fitting the core material attachment and a locking member for locking the core material attachment fitted to the matching groove. The core material attachment is inserted from the height direction into the mating grooves provided on both sides of the back side of the rod attachment, and the core material attachment and the rod attachment are mated and then locked. By projecting the tip of the locking rod provided on the member from the back surface of the rod attachment and fitting it into the locking hole provided in the core material attachment, the rod attachment can be attached to the core material attachment. It is characterized by wearing.

According to the above-described method for constructing a soil cement pile of the present invention, as a rotary press-fitting device for rotationally press-fitting an excavation stirring head into the ground, a structure similar to that of a pile driver used for construction of a low-flying space is provided. A rotary press-fitting device provided with a rotary drive device for rotating a rod-shaped member gripped from the side while moving along a leader is used. As a result, even when the work area for constructing the soil cement pile is a low head space, it is possible to secure a height space for performing the work of adding the foot rod to the excavation agitation head. As a result, it is possible to construct a soil cement column to a desired depth in the ground while adding a foot rod to the excavation agitation head with high work efficiency.

In the method of constructing the soil cement pile of the present invention, the rotary press-fitting device includes a rotary sensor for measuring the rotation speed of the rod-shaped member gripped from the side, a depth meter for measuring the tip position, and the rotary drive device. It is provided with a speed sensor for measuring the moving speed moving along the reader and a flow meter for measuring the discharge amount of the cement-based solidifying material discharged from the cement-based solidifying material discharge port provided in the excavation stirring head. It is characterized in that the rotation speed of the excavation stirring head, the penetration speed into the ground, the depth of the tip portion, and the discharge amount of the cement-based solidifying material are monitored by the rotary press-fitting device.

According to the construction method of the soil cement pile of the present invention, when constructing the soil cement column, the rotation speed of the excavation stirring head, the penetration speed into the ground, the depth of the tip portion, and the discharge amount of the cement-based solidifying material are determined. , Construction can be performed while managing with a rotary press-fitting device. As a result, the soil cement piles will be constructed with the same quality as when constructed by the soil cement pile construction method, which has been conventionally carried out by large heavy machinery, while significantly omitting the equipment required for the construction of soil cement columns. Is possible.

In the method of constructing the soil cement pile of the present invention, the core material is gripped from the side through the attachment for the core material by the chuck mechanism provided in the rotation drive device, and the soil cement pillar is formed. It is characterized in that the core material is built while being added by the rotary press-fitting device.

According to the construction method of the soil cement pile of the present invention, both the construction work of the soil cement column and the construction work of the core material can be carried out by the rotary press-fitting device. It is possible to save the trouble of carrying in separately. As a result, even if the planned construction site of the soil cement pile is under narrow conditions, the construction efficiency can be significantly improved.

In the method for constructing a soil cement pile of the present invention, a holding jig capable of holding the rod-shaped member from the side is installed so as to surround the planned construction position of the soil cement column, and the joint rod or the foot rod or It is characterized in that the joint rod or the core material is constantly supported by the rotary drive device or the holding jig during the addition work of at least one of the core materials.

According to the method for constructing a soil cement pile of the present invention, the excavation stirring head to which the footstock rod is added during the work of adding the footstock rod, and the core material at the time of the work of adding the core material are the soil cement columns before hardening. It is possible to prevent it from falling inside.

According to the present invention, it is possible to construct a soil cement pile having a required depth with high quality and high construction efficiency even if the planned construction site of the soil cement pile is in a low airspace or in a narrow condition.

It is a figure which shows the ground improvement apparatus in embodiment of this invention. It is a figure which shows the detail of the rotation drive device in embodiment of this invention. It is a figure which shows the attachment for the core material and the attachment for a rod of the rotation drive device in embodiment of this invention. It is a figure which shows the state which attached the attachment for the rod to the attachment for the core material of the rotation drive device in embodiment of this invention. It is a figure which shows the procedure of attaching a rod attachment to the core material attachment in embodiment of this invention (the 1). It is a figure which shows the procedure of attaching a rod attachment to the core material attachment in embodiment of this invention (the 2). It is a figure which shows the procedure of attaching a rod attachment to the core material attachment in embodiment of this invention (the 3). It is a figure which shows the state which supports the footing rod by the holding jig in embodiment of this invention. It is a figure which shows the construction method of the soil cement pile in embodiment of this invention (the 1). It is a figure which shows the construction method of the soil cement pile in embodiment of this invention (the 2). It is a figure which shows the construction method of the soil cement pile in embodiment of this invention (the 3). It is a figure which shows the state of supporting a steel pipe pile by the holding jig in embodiment of this invention.

The present invention utilizes a rotary press-fitting device that can build a rod-shaped member such as a prefabricated pile into the ground in a low-flying space or a construction site under narrow conditions as a ground improvement device. Then, a soil cement pillar is created, and a soil cement pile with a core material built into the soil cement pillar is constructed. The soil cement pile is a preparatory work to prepare the work environment, a soil cement pillar construction process to create a soil cement pillar in the ground, and a core material to be built while adding a core material of a predetermined length to the soil cement pillar. It is constructed through three steps, the building process.

The details of the construction method of the soil cement pile will be described below with reference to FIGS. 1 to 12, but prior to this, the ground improvement device used in the soil cement pillar construction process and the rotary press-fitting device used in the core material building process. , The holding jig used in the soil cement pillar construction process and the core material building process will be described. In this embodiment, a case where a steel pipe pile is used as the core material is taken as an example.

<Ground improvement device>
As shown in FIG. 1, the ground improvement device 21 used in the soil cement column construction process includes an excavation rod 22, an excavation stirring blade 23 arranged at the tip of the excavation rod 22, and a stirring blade 24 arranged above the excavation stirring blade 23. It is composed of an excavation stirring head 27 provided with a co-rotation prevention blade 25 and a cement-based solidifying material discharge port 26 installed in the vicinity of the excavation stirring blade 23, and a device for rotationally press-fitting the excavation stirring head 27 into the ground. Will be done.

In this embodiment, the cement-based solidifying material is discharged from the cement-based solidifying material discharge port 26, but if it is a ground improving material used when forming soil cement, a cement slurry or a cement slurry or Any of the cement-based solidifying material powders and the like may be discharged. Further, the co-rotation prevention blade 25 provided in the excavation stirring head 27 is rotatably installed with the excavation rod 22 as a rotation axis, and does not rotate in synchronization with the excavation stirring blade 23 and the stirring blade 24.

As a device for rotationally press-fitting the excavation and stirring head 27 into the ground, any equipment that can rotationally press-fit the excavation and stirring head 27 into the ground can be adopted. In the form of the above, a rotary press-fitting device 1 generally used when a rod-shaped member such as a ready-made pile or a core material is built in the ground is adopted in a low-flying space.

<Rotary press-fitting device>
The rotary press-fitting device 1 is installed behind a traveling body 2 provided with a crawler, a swivel device 3 installed above the traveling body 2, a driver's cab 4 that swivels via the swivel device 3, and a driver's cab 4. It is equipped with a power unit 5 that serves as a power source. Further, in front of the driver's cab 4, a leader 7 is installed so as to be able to stand up and down in the front-rear direction of the driver's cab 4 via an arm 6 connected to the driver's cab 4.

The leader 7 has a structure in which operations related to standing and lying down are performed by front and rear undulating cylinders 8 arranged so as to connect the back surface of the leader 7 facing the driver's cab 4 and the arm 6. Further, the elevating guide 9 is installed on the front surface of the leader 7, and the rotation driving device 11 is installed on the elevating body 10 that moves in the vertical direction along the elevating guide 9.

As shown in FIG. 2, the rotation drive device 11 has a through hole 12 penetrating in the vertical direction, a chuck mechanism 13 for gripping a rod-shaped member inserted through the through hole 12, and a rod-shaped member gripped by the chuck mechanism 13. It is equipped with a rotation drive unit (not shown) that rotates horizontally. The chuck mechanism 13 includes a plurality of expansion / contraction means 132 which are arranged at intervals along the inner circumference of the through hole 12 and expand / contract in a direction orthogonal to the axis of the through hole 12, and extend the plurality of expansion / contraction means 132. The rod-shaped member is gripped by pressing the side peripheral surface of the rod-shaped member penetrating the through hole 12 at its tip. The telescopic means 132 may be any device such as a hydraulic jack or a mechanical jack as long as it is a stretchable device.

As described above, the rotary drive device 11 that grips the rod-shaped member from the side by the through hole 12 is rotationally driven as compared with the rotary drive device that grips the rod-shaped member from above using the swivel joint. Since the stroke when the device 11 is moved up and down along the raising and lowering guide 9 provided in the leader 7 is not wasted, it is suitable for use in a low head space.

By the way, in the present embodiment, a core material is used to grip the steel pipe pile P to be built in the soil cement column S in the steel pipe building step as shown in FIG. 11 at the tip of the expansion / contraction means 132 constituting the chuck mechanism 13. The attachment 131 is detachably installed. As shown in FIG. 3A, the core material attachment 131 is made of three plate materials in which the side ends are connected to each other so as to form an obtuse angle, and the rough surface 1311 is on the front surface facing the outer peripheral surface of the steel pipe pile P. Is formed, and the telescopic means 132 is detachably installed on the back surface.

Therefore, as shown in FIG. 2, when the plurality of expansion / contraction means 132 to which the core material attachment 131 is attached are extended with the steel pipe pile P penetrating through the through hole 12, the rough surface 1311 of the plurality of core material attachment 131 is extended. Each abuts on the side peripheral surface of the steel pipe pile P. When the expansion / contraction means 132 is further extended in this state, the steel pipe pile P is pressed from all sides by the plurality of core material attachments 131 and is gripped by the chuck mechanism 13. The rotary drive device 11 that grips the steel pipe pile P in this way moves up and down along the elevating guide 9 via the elevating body 10. As a result, the steel pipe pile P can be built in the ground by the rotary press-fitting device 1.

When the rotary press-fitting device 1 having the above-described configuration is used as a device for rotationally press-fitting the excavation stirring head 27 into the ground as described above, the rod is further attached to the core material attachment 131. Attach the attachment 14.

<Attachment for rod>
As shown in FIG. 3B, the rod attachment 14 is provided on the rod chuck plate material 141, the back plate material 142 arranged in parallel with the rod chuck plate material 141, and both side portions on the back surface side of the back plate material 142. A fitting groove 143 and a pair of space holding plates 144 for connecting the back plate material 142 and the rod chuck plate material 141 are provided. The rod attachment 14 is an attachment for gripping the foot rod 28 to be added to the excavation rod 22 constituting the excavation stirring head 27, as shown in FIG.

Similar to the attachment 131 for the core material, the chuck plate material 141 for the rod is composed of three plate materials in which the side ends are connected so as to form an obtuse angle, and a rough surface 1411 is formed on the front surface facing the joint rod 28. ing. The back plate material 142 is also composed of three plate materials in which the side ends are connected to each other so as to form an obtuse angle, and the back surface thereof is formed in a shape along the front surface of the core material attachment 131.

The fitting groove 143 has a groove width into which the core material attachment 131 inserted from the height direction can be fitted, and the space holding plate 144 has the core material attachment 131 fitted in the fitting groove 143. In this state, the distance between the core material attachment 131 and the rod chuck plate material 141 is adjusted to a size equal to the difference in the radius of gyration between the steel pipe pile P and the foot rod 28. As a result, as shown in FIG. 4, when the rod attachment 14 is attached to each of the plurality of core material attachments 131, the through hole 12 of the rotation drive device 11 has a narrowness suitable for gripping the foot rod 28. Space is formed.

Therefore, as shown in FIG. 4, when the plurality of expansion / contraction means 132 are extended in the same manner as when the steel pipe pile P is gripped with the foot rod 28 inserted through the through hole 12, the foot rod 28 is expanded. The rod attachments 14 are pressed from all sides, and the chuck mechanism 13 grips the rods. The rotation drive device 11 that grips the joint rod 28 in this way rotates the joint rod 28 in the horizontal direction by the rotation drive unit, and moves up and down along the elevating guide 9 via the elevating body 10. As a result, the excavation agitation head 27 to which the joint rod 28 is added can be press-fitted into the ground by the rotary press-fitting device 1 while rotating horizontally.

The rod attachment 14 can be attached to the chuck mechanism 13 by the procedure shown in FIGS. 5 to 7.

<How to attach the rod attachment>
First, the rotation drive device 11 and the elevating body 10 are operated to arrange the core material attachment 131 attached to the telescopic means 132 at a position higher by a predetermined amount, as shown in FIG. 5 (b). Next, the rod attachment 14 is placed on the ground surface, and as shown in FIG. 5A, the fitting groove 143 and the core material attachment 131 are aligned in the vertical direction. After that, the rotation drive device 11 is lowered, and as shown in FIG. 6A, the core material attachment 131 is fitted into the fitting groove 143. Then, as shown in FIG. 7B, the rod attachment 14 is locked to the core material attachment 131 via the locking member 15.

As shown in FIG. 7B, the locking member 15 has a locking rod 151 penetrating a through hole formed near the center of the upper end portion of the back plate member 142 of the rod attachment 14, and a locking rod 151 penetrating the locking rod 151. The holding cylinder 152, which is possible and is provided so as to communicate with the through hole formed in the back plate material 142, and the tip of the locking rod 151 are fixed in both the state of protruding from the back surface of the back plate material 142 and the state of being stored. It is equipped with a possible lock mechanism 153.

Further, the lock mechanism 153 includes a lock pin 1531 integrally fixed so as to project from the side peripheral surface of the locking rod 151, and a lock groove 1532 formed in the holding cylinder 152 and through which the lock pin 1531 penetrates. ing. The lock groove 1532 is formed in a U-shape with an opening downward, consisting of a horizontal groove extending in the axial direction of the holding cylinder 152 and a pair of vertical grooves extending in the circumferential direction of the holding cylinder 152 from both ends of the horizontal groove. Has been done.

Then, as shown in FIG. 5B, the rod attachment 14 before being attached to the rotary drive device 11 accommodates the tip of the locking rod 151, and the lock pin 1531 is dropped into the vertical groove of the lock groove 1532. The locking rod 151 is fixed so as not to move. When it is desired to project the locking rod 151 in such a stored state toward the core material attachment 131, it is dropped into the vertical groove of the locking groove 1532 as shown in FIG. 6 (b). Pull up the lock pin 1531 to the lateral groove of the lock groove 1532.

Then, as shown in FIG. 7A, the lock pin 1531 is moved toward the core material attachment 131 along the lateral groove of the lock groove 1532. Then, since the locking rod 151 also moves toward the core material attachment 131 together with the lock pin 1531, the tip of the locking rod 151 protrudes from the back surface of the back plate material 142 of the rod attachment 14. In this state, by dropping the lock pin 1531 into the vertical groove of the lock groove 1532, the locking rod 151 is fixed in a state where the tip is projected.

At this time, in the core material attachment 131, a locking hole 1312 capable of accommodating the locking rod 151 is formed at a position facing the tip of the locking rod 151 in a state where the rod attachment 14 is attached. .. Therefore, when the tip of the locking rod 151 is projected from the back surface of the back plate material 142 with the core material attachment 131 fitted in the fitting groove 143 of the rod attachment 14, the tip of the locking rod 151 is shown in the figure. As shown in 7 (a), it is fitted into the locking hole 1312 of the core material attachment 131.

As a result, the rod attachment 14 is locked to the core attachment 131 via the locking member 15. Therefore, by operating the rotation drive device 11 to raise the core material attachment 131, the rod attachment 14 can be attached to the chuck mechanism 13 in a manner of being suspended from the core material attachment 131.

If it is desired to store the locking rod 151 having the tip protruding from the back plate material 142 in the rod attachment 14, the lock pin 1531 dropped into the vertical groove of the lock groove 1532 may be inserted into the horizontal groove of the lock groove 1532. And move the lock pin 1531 along the lateral groove of the lock groove 1532 toward the rod chuck plate material 141. Then, by dropping the lock pin 1531 into the vertical groove of the lock groove 1532, the tip of the locking rod 151 can be fixed in a retracted state.

<Holding jig>
Next, the holding jig 41 used when the joint rod 28 is sequentially added to the excavation rod 22 constituting the excavation stirring head 27 will be described. The sandwiching jig 41 may be used as long as it has a structure capable of sandwiching the joint rod 28, but in the present embodiment, not only the joint rod 28 but also the steel pipe pile P is sandwiched. A jig having a structure capable of this is adopted.

As shown in FIG. 8A, the holding jig 41 is mounted on a plate-shaped base frame 42 having a through hole 421 in the center and on the upper surface of the base frame 42, and faces the through hole 421 of the base frame 42. It is provided with a plate-shaped automatic frame base 43 having a through hole 431 having the same diameter at the position where the jig is formed and having a smooth sliding surface on the upper surface. Further, four pinching mechanisms 44 which are placed on the upper surface of the automatic frame base 43 and are arranged at equal intervals so as to extend in the radial direction from the axial center of the through hole 421, and each of the pinching mechanisms 44 of the through hole 421. It is provided with four slide mechanisms 45 that slide freely toward the axis.

The sandwiching mechanism 44 is mounted on the upper surface of the automatic frame base 43, and is provided on the load bearing member 441 formed of a hollow square cylinder whose axis is oriented in the advancing / retreating direction by the slide mechanism 45, and on the through hole 421 side of the load bearing member 441. It is provided with a wedge-shaped member 442 provided in the vicinity of the located front end opening.

The wedge-shaped member 442 is rotatably connected to the inner sky upper surface of the load-bearing member 441 via an extrusion cylinder 443 in a posture in which the acute-angled portion faces downward. Further, the vicinity of the lower end portion is rotatably installed on the inner and lower surfaces of the load bearing member 441 via the pin support 444. As a result, when the extrusion cylinder 443 is extended, the wedge-shaped member 442 has a front end opening of the load bearing member 441 with the pin support 444 installed near the lower end as a rotation axis as shown in FIG. 8 (b). When the extrusion cylinder 443 is rotated so as to protrude from the portion and the extrusion cylinder 443 is contracted, the upper end portion is housed in the front end opening of the load bearing member 441.

Further, in the load-bearing member 441, an outer surface that comes into contact with the automatic frame base 43 is formed on a sliding surface, and one end of the slide mechanism 45 is inserted from the rear end opening, and one end of the slide mechanism 45 is inserted into the inner space of the load-bearing member 441. It is fixed to the bottom surface. On the other hand, the other end of the slide mechanism 45 is fixed to the upper surface of the automatic frame base 43, and when the slide mechanism 45 is extended, the load bearing member 441 slides on the automatic frame base 43 and faces the axis of the through hole 421. When the slide mechanism 45 is contracted, it slides on the automatic frame base 43 and moves backward.

The holding jig 41 having the above-described configuration is installed on the work floor 33 so that the through holes 421 of the base frame 42 and the axes of the leading holes 31 match each other, and is inserted into the leading holes 31. Further, the joint rod 28 penetrating the through hole 421 of the base frame 42 is sandwiched by the four sandwiching mechanisms 44.

In the procedure, first, as shown in FIG. 8A, the slide mechanism 45 is extended to project each of the four load-bearing members 441 toward the foot rod 28, and the vicinity of the front end opening of the load-bearing member 441. The wedge-shaped member 442 installed in the above is arranged close to the joint rod 28. Next, as shown in FIG. 8B, the extrusion cylinder 443 is extended so that the upper end portion of the wedge-shaped member 442 comes into contact with the side peripheral surface of the joint rod 28. Then, by further extending the extrusion cylinder 443, the joint rod 28 is pressed from all sides by the four wedge-shaped members 442, and is sandwiched by the sandwiching jig 41.

By moving the load bearing member 441 back and forth via the slide mechanism 45 in this way, the position of the wedge-shaped member 442 with respect to the axis of the through hole 421 provided in the base frame 42 can be freely adjusted. Therefore, by forming the through hole 421 of the base frame 42 into a size capable of penetrating the steel pipe pile P, as shown in FIG. 12, the holding jig 41 is used not only for the foot rod 28 but also for the steel pipe. It is also possible to sandwich the pile P.

Further, when the foot rod 28 tries to move downward due to its own weight, the wedge-shaped member 442 rotates so that the upper end portion is further bitten by the foot foot rod 28 with the pin support 444 near the lower end portion as the rotation axis. .. This makes it possible to securely hold the joint rod 28. In this embodiment, a saw blade 4421 is provided at a portion of the wedge-shaped member 442 that comes into contact with the excavation rod 22, so that the excavation rod 22 can be more reliably sandwiched.

Further, by providing the load-bearing member 441, the load of the joint rod 28 sandwiched by the wedge-shaped member 442 is transmitted to the load-bearing member 441. As a result, the load load on the extrusion cylinder 443 and the slide mechanism 45 can be dispersed, and damage to the extrusion cylinder 443 and the slide mechanism 45 can be prevented. The extrusion cylinder 443 and the slide mechanism 45 may be made of any device such as a hydraulic jack or a mechanical jack as long as it is a stretchable device.

<Construction method of soil cement pile>
The method of constructing the soil cement pile using the ground improvement device 21, the rotary press-fitting device 1, and the holding jig 41 described above will be described step by step below.

<Preparatory work>
As shown in FIG. 9A, the mouth pipe 32 is installed in the hole wall of the leading hole 31 formed by excavating the planned construction position of the soil cement pile C from the ground surface.

Next, on the ground surface around the mouth pipe 32, a work floor 33 for supporting the heavy machinery used when constructing the soil cement pile and using it as a work area is installed. In addition to these operations, a mud drainage pit 34 is constructed, and the opening of the mud drainage pit 34 is cured with the opening curing material 35.

<Soil cement pillar construction process>
By rotating and press-fitting the excavation stirring head 27 into the ground using the leading hole 31 constructed by the preparatory work, the excavated soil is stirred and mixed while injecting the cement-based solidifying material to create the soil cement column S. do.

First, the excavation agitation head 27 is suspended by a crane M and inserted into the mouth pipe 32, and the excavation agitation head 27 is placed on the work floor via a temporary support plate 36 made of, for example, a half split of a lining plate. Temporarily support 33. Next, in order to bring the tip of the excavation agitation head 27 to the bottom of the leading hole 31, a required number of extension rods 28 are added to the excavation rod 22 of the excavation agitation head 27 using a crane M, and the excavation agitation head 27 is added. The tip of the head is lowered until it reaches the bottom of the leading hole 31.

After that, the holding jig 41 is installed on the work floor 33 so that the foot rod 28 located at the uppermost portion is inserted. The holding jig 41 is positioned so that the axis of the through hole 421 provided in the base frame 42 and the axis of the desired soil cement pile C to be constructed coincide with each other.

Next, the crane M is retracted, and as shown in FIG. 9B, the rotary press-fitting device 1 constituting the ground improvement device 21 is carried in and installed at a predetermined position on the work floor 33. The rotation drive device 11 of the rotation press-fitting device 1 is equipped with a rod attachment 14 on the chuck mechanism 13 according to the procedure described above. Then, the portion of the joint rod 28 protruding upward from the holding jig 41 is passed through the through hole 12 of the rotary drive device 11 provided in the rotary press-fitting device 1. After that, the upper end of the joint rod 28 is gripped by the chuck mechanism 13 of the rotary drive device 11, and the excavation stirring head 27 is supported by the rotary drive device 11.

In this state, the trailing foot rod 28 is added to the foot rod 28 that was added in advance. The trailing foot rod 28 is suspended from the tip of the arm 171 of the suspension device 17 installed at the upper end of the leader 7 via the swivel member 16 via the wire 172. Then, the arm 171 of the suspension device 17 is swiveled via the swivel member 16 so that the axis of the trailing leg leg 28 coincides with the axis of the preceding leg rod 28 for positioning. After that, the wire 172 is extended by the winch 173 to suspend the joint rod 28, and the succeeding joint rod 28 is added to the preceding joint rod 28.

Next, as shown in FIG. 8B, the preceding joint rod 28 is sandwiched by the holding mechanism 44 of the holding jig 41 to support the excavation stirring head 27, and the preceding joint of the rotary drive device 11 is supported. Release the grip on the rod 28. Then, the rotary drive device 11 is raised along the elevating guide 9, and as shown in FIG. 1, the upper end of the trailing excavation rod 22 is gripped by the chuck mechanism 13 of the rotary drive device 11 and FIG. As shown in a), the pinching of the pinching jig 41 with respect to the preceding joint rod 28 by the pinching mechanism 44 is released. From this state, the construction work of the soil cement column S is started while adding the joint rod 28 by the following procedure.

Specifically, as shown in FIG. 10A, the excavation stirring head 27 in which the cement-based solidifying material is discharged from the cement-based solidifying material discharge port 26 is rotated by the rotation driving unit of the rotation driving device 11. , The rotation drive device 11 is lowered along the elevating guide 9. As a result, the excavation stirring blade 23 and the stirring blade 24 of the excavation stirring head 27 are rotationally press-fitted into the ground, and the cement-based solidifying material and the excavated soil are stirred and mixed to form a soil cement column S. Then, when the rotation drive device 11 descends to the lower end of the elevating guide 9, the work of creating the soil cement column S is interrupted.

After that, as shown in FIG. 10B, the trailing foot rod 28 is added to the foot rod 28 that preceded again by the above procedure, and the foot that precedes the foot by the pinching mechanism 44 of the pinching jig 41. The rod 28 is sandwiched to support the excavation stirring head 27, and the rotation drive device 11 is released from gripping the preceding joint rod 28. Next, the rotary drive device 11 is raised to grip the upper end of the trailing leg leg rod 28 by the chuck mechanism 13 of the rotary drive device 11, and the preceding leg leg rod 28 is gripped by the pinch mechanism 44 of the pinch jig 41. The pinching of the soil cement column S is released, and the above-mentioned construction work of the soil cement column S is resumed.

As described above, the excavation stirring head 27 is always supported by either means of gripping the leg foot rod 28 by the rotary drive device 11 or pinching the leg foot rod 28 by the pinch mechanism 44 of the pinch jig 41. As a result, it is possible to prevent the excavation stirring head 27 from falling onto the soil cement column S being constructed during the work of adding the joint rod 28.

While adding the above-mentioned joint rod 28, the work of creating the soil cement column S is repeated to create the soil cement column S to a desired depth. After the construction work of the soil cement pillar S is completed, the excavation stirring head 27 is raised while removing the foot joint rod 28 in the reverse procedure of the case of adding the foot joint rod 28, and the excavation stirring head is raised from the soil cement pillar S. Pull out 27 and remove it.

The excavation agitation head 27 is connected to a ground improvement facility (not shown) generally used when performing ground improvement, and a cement-based solidifying material is supplied, and the rotation speed of the excavation agitation head 27 is increased. The penetration speed, the depth of the excavation stirring blade 23, and the discharge amount of the cement-based solidifying material are at least controlled. Further, the tip of the soil cement column S is preliminarily blended with a cement-based solidifying material discharged from the cement-based solidifying material discharge port 26 so that a soil cement having a rich content is formed from the general part of the soil cement column S. You can also adjust it.

<Core material building process>
In the soil cement creating process, after the soil cement column S was created and the excavation stirring head 27 was removed, the rod attachment 14 attached to the chuck mechanism 13 in the rotary drive device 11 of the rotary press-fitting device 1 was removed, and the core material was removed. Only the attachment 131 is installed. Then, the steel pipe pile P is added to the soil cement column S before hardening and built.

As shown in FIG. 11A, the construction work of the steel pipe pile P is performed via the wire 172 at the tip of the arm 171 of the suspending device 17 in a state where the rotary drive device 11 is located at the lower end of the elevating guide 9. The steel pipe pile P is suspended. Next, the arm 171 of the suspension device 17 is swiveled via the swivel member 16 so that the axis of the steel pipe pile P coincides with the axis of the steel pipe pile P built in advance, and the position of the steel pipe pile P is positioned. I do. After that, the wire 172 is unwound to suspend the steel pipe pile P, the lower end thereof is brought into contact with the upper end of the preceding steel pipe pile P, and the two are joined by various means such as mechanical joints and welding.

Next, as shown in FIG. 12B, the steel pipe pile P built in advance of the soil cement column S is sandwiched by the sandwiching mechanism 44 of the sandwiching jig 41 by the above procedure. After that, the rotary drive device 11 releases the gripping of the preceding steel pipe pile P and raises the rotary drive device 11, and as shown in FIG. 11B, the vicinity of the upper end of the added steel pipe pile P is connected to the chuck mechanism 13. To be grasped. After that, the wire 172 is removed from the steel pipe pile P, and as shown in FIG. 12A, the preceding steel pipe pile P is released from being pinched by the pinching jig 41. Then, the rotary drive device 11 is lowered, and the steel pipe pile P is built in the soil cement column S while penetrating the through hole 421 of the holding jig 41.

The steel pipe pile P penetrates into the soil cement column S by its own weight and is built, but if it does not penetrate only by its own weight, the rotary drive device 11 rotates the steel pipe pile P and lowers the rotary drive device 11. , It is advisable to rotate and press-fit it into the soil cement column S to build it. Then, as shown in FIG. 11C, when the rotary drive device 11 descends to the lower end of the elevating guide 9, the construction work of the steel pipe pile P is interrupted, and the newly added steel pipe pile P is suspended and joined. Do the work of adding. This procedure is repeated until the tip of the steel pipe pile P located at the lowermost end reaches a desired depth, and the construction work of the soil cement pile C is completed.

As described above, even in the core material building process, the steel pipe pile P is always supported by either gripping by the rotary drive device 11 or pinching by the pinching mechanism 44 of the pinching jig 41. As a result, it is possible to prevent the steel pipe pile P from falling onto the soil cement column S during the replenishment work of the steel pipe pile P.

When the first steel pipe pile P is built in the soil cement column S, the rotation drive device 11 is positioned at the lower end of the elevating guide 9, and then the axial center of the first steel pipe pile P is desired. The steel pipe pile P is positioned by the suspension device 17 so as to match the axis of the planned soil cement pile C, and the rotation drive device 11 is raised so that the chuck mechanism 13 grips the vicinity of the upper end of the steel pipe pile P. Next, the wire 172 is removed from the steel pipe pile P, and the rotary drive device 11 is lowered.

Then, as shown in FIG. 12A, the steel pipe pile P penetrates the through hole 421 of the holding jig 41 and is built in the soil cement column S. Then, when the rotary drive device 11 descends to the lower end of the elevating guide 9, the construction work of the steel pipe pile P may be interrupted, and the new steel pipe pile P may be suspended by the above procedure.

According to the construction method of the soil cement pile of the present invention, the rotary press-fitting device 1 is adopted as the ground improvement device 21, and the excavation stirring head 27 is rotationally press-fitted into the ground by the rotary press-fitting device 1. As a result, even when the work area for constructing the soil cement pile C is a low head space, it is possible to secure the necessary height space for performing the work of adding the foot rod 28 to the excavation agitation head 27. Therefore, it is possible to construct the soil cement column S to a desired depth in the ground while efficiently adding the foot rod 28 to the excavation stirring head 27.

Further, the rotary press-fitting device 1 can perform both the construction work of the soil cement column S and the construction work of the steel pipe pile P. This is compared with the method in which the ground improvement equipment is brought into the construction site during the construction work of the soil cement column S, and then the ground improvement equipment is removed and the pile driver is carried in during the construction work of the steel pipe pile. Therefore, it is possible to significantly improve the construction efficiency related to the construction of the soil cement pile C even under narrow conditions.

The method for constructing the soil cement pile of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention.

For example, the rotary press-fitting device 1 has a rotary sensor that measures the number of rotations of a rod-shaped member gripped from the side by the rotary drive device 11, and the moving speed of the rotary drive device 11 that moves along the elevating guide 9 provided in the reader 7. The speed sensor for measuring the speed, the depth meter for measuring the position of the tip of the rod-shaped member gripped from the side by the rotation drive device 11, and the excavation stirring head 27 when the excavation stirring head 27 is supported by the rotation drive device 11. A flow meter for measuring the discharge amount of the cement-based solidifying material discharged from the cement-based solidifying material discharge port 26 may be provided.

Then, in the process of constructing the soil cement column S, the rotation speed of the excavation stirring head 27, the penetration speed into the ground, the depth of the tip portion, and the discharge amount of the cement-based solidifying material are controlled by the rotary press-fitting device 1. However, the soil cement pillar S can be constructed. As a result, while omitting the carry-in and installation of the ground improvement equipment that is generally used when constructing the soil cement pillar S, the quality is equivalent to that of the soil cement pile construction method that has been conventionally implemented by large heavy machinery. It is possible to construct the soil cement pile C that secures the above.

Further, in the present embodiment, the excavation stirring head 27 provided with the co-rotation prevention blade 25 is adopted, but the present invention is not necessarily limited to this, and a mechanism in which the excavation stirring blade 23 and the stirring blade 24 rotate in the forward and reverse directions is provided. A two-axis type excavation stirring head 27 provided may be adopted. In this case, two rotary drive units are mounted on the rotary drive device 11 of the rotary press-fitting device 1 in order to rotate the excavation stirring blade 23 and the stirring blade 24 in the forward and reverse directions.

Further, the shapes of the core material attachment 131 and the rod attachment 14 are not necessarily limited to the above-mentioned shapes, respectively. Any shape can be adopted as long as it is detachable from the tip of the telescopic means 132 in the chuck mechanism 13 of the rotary drive device 11 and has a structure capable of gripping the steel pipe pile P and the joint rod 28, respectively. May be good.

Similarly, the holding jig 41 is not necessarily limited to the above-mentioned structure, and any structure can be used as long as it has a structure capable of holding both the steel pipe pile P and the joint rod 28. It may be adopted.

Further, the sandwiching jig 41 does not necessarily have to be usable in both the soil cement column forming process and the core material building process, and in the soil cement column forming process, a jig capable of sandwiching the joint rod 28 is provided. Further, in the core material building process, jigs capable of sandwiching the steel pipe pile P may be separately adopted.

Further, in the present embodiment, the steel pipe pile P is adopted as the core material of the soil cement pile C, but the present invention is not necessarily limited to this. Any material that can be built into the soil cement column S, such as a square steel pipe, H-shaped steel, or steel sheet pile, and can form the soil cement pile C may be used. In this case, the shape of the core material attachment 131 provided in the chuck mechanism 13 of the rotation drive device 11 may be appropriately changed according to the cross-sectional shape of the core material.

1 Rotating press-fitting device 2 Traveling body 3 Swinging device 4 Driver's cab 5 Power unit 6 Arm 7 Leader 8 Front and rear undulating cylinder 9 Elevating guide 10 Elevating body 11 Rotating drive device 12 Through hole 13 Chuck mechanism 131 Core material attachment 1312 Locking hole 132 Expansion and contraction Means 14 Rod attachment 141 Rod chuck plate 142 Back plate 143 Fitting groove 144 Interval holding plate 15 Locking member 151 Locking rod 152 Holding cylinder 153 Locking mechanism 1531 Lock pin 1532 Locking groove 16 Swivel member 17 Hanging device 171 Arm 172 Wire 173 Winch 21 Ground improvement device 22 Excavation rod 23 Excavation stirring blade 24 Stirring blade 25 Co-rotation prevention blade 26 Cement-based solidifying material discharge port 27 Excavation stirring head 28 Joint rod

31 Leading hole 32 Mouth pipe 33 Work floor 34 Mud drain pit 35 Opening curing material 36 Temporary support plate 41 Holding jig 42 Base frame 43 Automatic frame base 44 Holding mechanism 441 Load bearing member 442 Wedge-shaped member 443 Extruded cylinder 444 Pin support 45 Slide mechanism C Soil cement pile S Soil cement pillar P Steel pipe pile (core material)
M crane

Claims (5)

Construction of soil cement piles, in which a splicing rod is added to the excavation rod provided in the excavation and stirring head, and the core material is added to the soil cement column created by rotationally press-fitting the excavation and stirring head into the ground. It ’s a method,
An attachment for a core material is attached to a chuck mechanism provided in the rotation drive device of a rotary press-fitting device provided with a rotary drive device that rotates a rod-shaped member gripped from the side while moving along a leader. The rod attachment is attached to the rod, and the joint rod is gripped from the side by the chuck mechanism via the rod attachment.
A method for constructing a soil cement pile, wherein the excavation agitation head is rotationally press-fitted into the ground by the rotary press-fitting device. In the method for constructing a soil cement pile according to claim 1,
The rod attachment is provided with a matching groove capable of fitting the core material attachment and a locking member for locking the core material attachment fitted to the matching groove.
The core material attachment is inserted into the fitting grooves provided on both sides of the back surface side of the rod attachment from the height direction, and the core material attachment and the rod attachment are fitted together.
The tip of the locking rod provided on the locking member is projected from the back surface of the rod attachment and is fitted into the locking hole provided in the core material attachment, whereby the rod is attached to the core material attachment. A method of constructing a soil cement pile, which is characterized by attaching a mounting attachment. In the method for constructing a soil cement pile according to claim 1 or 2.
In the rotary press-fitting device, a rotation sensor for measuring the number of rotations of the rod-shaped member gripped from the side, a depth meter for measuring the position of the tip portion, and a moving speed at which the rotation drive device moves along the reader are measured. It is equipped with a speed sensor for measuring the discharge amount of the cement-based solidifying material discharged from the cement-based solidifying material discharge port provided in the excavation stirring head, and a flow meter for measuring the discharge amount of the cement-based solidifying material.
A method for constructing a soil cement pile, characterized in that the rotation speed of the excavation stirring head, the penetration speed into the ground, the depth of the tip portion, and the discharge amount of the cement-based solidifying material are monitored by the rotary press-fitting device. .. In the method for constructing a soil cement pile according to any one of claims 1 to 3 ,
The chuck mechanism provided in the rotation drive device grips the core material from the side via the attachment for the core material.
A method for constructing a soil cement pile, which comprises adding the core material to the created soil cement column with the rotary press-fitting device. In the method for constructing a soil cement pile according to any one of claims 1 to 4 .
A holding jig that can hold the rod-shaped member from the side is installed so as to surround the planned construction position of the soil cement column.
A soil characterized in that the foot rod or the core material is constantly supported by the rotary drive device or the holding jig during the work of adding at least one of the foot rod or the core material. Construction method of cement pile.

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