JPH0584770B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention is an apparatus used in a deep mixing compacted soil construction method for creating compacted soil in the ground in order to improve soft ground. This invention relates to a device for inserting reinforcing reinforcing bar cages into compacted soil.

《Prior art》 As a type of method for improving soft ground, the deep mixed compacted soil method is known, which creates compacted soil in soft ground.The compacted soil created by this method is usually It is made by injecting cement milk into the soil and solidifying the soil cement mixed with earth and sand, and the solidified soil is created in close proximity to each other, and is sometimes constructed in columnar rows.

When external forces such as earth pressure act on the sides of soil cement columns formed using this construction method, a tensile force acts on one side and a compressive force acts on the opposite side.

Soil cement generally exhibits considerable strength against compressive force, but is weak against tensile force and is prone to cracking when external forces such as earth pressure act on it.

Conventionally, such problems have been dealt with by increasing the improved area when viewed in plan.

However, by inserting reinforcing steel into the soil cement columns, it is possible to provide bending strength and increase shear strength without increasing the improvement area.

Therefore, the present applicant has previously proposed an insertion guide device for reinforcing steel material in the deep stirring mixed earth construction method shown in Japanese Utility Model Application Publication No. 62-129437, or a reinforcing steel material insertion guide device in the deep mixing compaction earth construction method shown in Japanese Utility Model Application Publication No. 62-129436. We have developed a reinforcing steel insertion device.

In the former case, it is a device that directly pushes multiple pieces of steel into soil cement using rollers or the like.

In the case of the latter, the reinforcing steel material is inserted into the pipe-shaped casing in advance, and the casing is pushed into the soil cement by applying vibration and impact using a vibrohammer, and the reinforcing steel material is removed by pulling out the casing. is left inside the soil cement.

However, such a device for pushing reinforcing steel materials has the following technical problems.

<<Problems to be Solved by the Invention>> In other words, in the case of the former device that directly pushes the steel material, there is a problem that the steel material is likely to buckle because the pushing force is applied by the rotation of the roller from the rear end of the steel material into the soil cement. It was hot.

On the other hand, in the latter device using a casing, the reinforcing steel is covered by the casing and pushed into the soil cement, so a large pushing force does not directly act on the steel, so buckling of the steel is prevented, but the following: There was another problem to explain.

In this type of construction method, when reinforcing steel is pushed into soil cement, the hardening reaction of the cement has progressed to some extent, and when the casing is pulled out to leave the reinforcing steel, the hardening reaction continues. As the process progresses, the soil cement reaches a state where its strength is considerably developed.

Therefore, when the casing is pulled out, an annular cavity is created around the outer periphery of the reinforcing steel, but since the strength of the soil cement has been developed, this cavity is not completely backfilled, and the interaction between the reinforcing steel and the soil cement is not complete. There was a problem that the reinforcing effect of the steel material was not sufficiently exhibited due to insufficient adhesion between the two.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to prevent buckling of reinforcing members that are pushed into mixed compacted soil, and to improve the rigidity of the reinforcing members. It is an object of the present invention to provide a device for pushing reinforcing reinforcing bar cages in a deep mixed compacted earth construction method, which can ensure sufficient adhesion between compacted soil and reinforcing members.

<<Means for Solving the Problems>> In order to achieve the above object, the present invention provides a reinforcing reinforcing bar cage inserted into mixed compacted soil before consolidation formed in soft ground, and a reinforcing bar cage that is pushed into the reinforcing bar cage. In the pushing device, the reinforcing bar cage includes a notch provided along the vertical direction at one end in the circumferential direction, a reinforcing ring provided at the lower end of the notch, and a reinforcing ring provided at the center of the reinforcing ring. The pushing means includes a pressure receiving part that receives pushing pressure and a guide part provided at the upper end of the reinforcing bar cage, and the pushing means is detachably attached to the pressure receiving part and the guide part, A pushing member that penetrates and applies a pushing force to the upper end, a leader that vertically supports the reinforcing bar cage through the pushing member, and a leader that protrudes into the reinforcing bar cage from the lower part of the leader through the notch. It is characterized by comprising an insertion guide that slidably supports the pushing member fixed to the leader.

<<Operation>> According to the above configuration, the pushing force applied to the reinforcing reinforcing bar cage is transmitted from the upper end of the pushing member to its lower end, and then to the tip side of the reinforcing bar cage via the pressure receiving part, Since the reinforcing bar cage is inserted by being dragged into the compacted soil from the tip side by this force, there is no force acting on the reinforcing bar cage that would cause it to buckle.

In addition, since the cavity created when the pushing member is pulled out is in the center of the reinforcing reinforcing bar cage, even if the void is not completely backfilled, the adhesion between the reinforcing reinforcing bar cage and the mixed compacted soil will be affected. No impact.

<<Example>> Hereinafter, an example of the present invention will be described in detail using the drawings.

Figures 1a to 1c show the overall structure of the device of this invention and the construction sequence using this device.

In the figure, 1 is a mixed compacted soil column, that is, a soil cement column, formed in soft ground E by the deep stirring and mixing method.

A traveling truck 2 is located near the ground surface of the soil cement column 1, and a leader 3 made of a truss-shaped column is mounted on the front side of the traveling truck 2 and is installed vertically.

As shown in FIG. 2, on the front side of the leader 3, there is a pair of lifting guides 3a provided in the longitudinal direction of the leader 3.
Guide block 4 movable vertically along
is arranged, and a vibrohammer 5 is arranged on this guide block 4.

The lower end of the guide block 4 is connected to the upper end of a push-in pipe 6 as a push-in member.

This push-in pipe 6 has a rectangular cross section, and a grip plate 6a is integrally welded to its upper part.
The push-in pipe 6 is removably connected to the lower part of the guide block 4 by gripping the gripping plate 6a by a pair of clamps 4a and 4b for a hydraulic chuck provided on the lower surface of the guide block 4.

Furthermore, an insertion guide 7 that slidably grips the outer circumferential portion of the push-in pipe 6 is provided on the lower front side of the leader 3.

As shown in FIG. 3, this insertion guide 7 has its base integrally welded to the above-mentioned lifting guide 3a provided on the front side of the leader 3, and has an angle member 7.
a pair of plates 7b that are reinforced by a and protrude in parallel at intervals equal to the diameter of the push-in pipe 6;
, a guide plate 7c welded between each plate 7b, and a lock plate 7e that is hooked into and removed from a recess 7d formed on the tip side of each plate 7b, and allows the push-in pipe 6 to be attached to each plate. 7b, and while it is in contact with the guide plate 7c, insert the lock plate 7e into the recess 7d.
By being hooked to the plate, the push-in pipe 6 is surrounded in a positioned manner between each plate 7b, guide plate 7c, and lock plate 7e, and is held inside thereof so as to be slidable only in the vertical direction.

With the above configuration, the push-in pipe 6 can be moved up and down along the insertion guide 7 in parallel to the vertical direction of the leader 3 with its upper end connected to the guide block 4.

Further, an annular reinforcing bar cage 8 is supported around the outer circumferential portion of the push-in pipe 6 so that the upper end of the pipe 6 projects.

This reinforcing bar cage 8 is made of a combination of multiple vertical bars 8a and circular horizontal bars 8b, like a general reinforcing bar cage, but the difference is that, as shown in FIG. 4, one of the horizontal bars 8b is This notch 9 is formed continuously in the vertical direction, and the guide 7 that supports the push-in pipe 6 can be inserted into the reinforcing bar cage 8 through the notch 9. being done.

That is, as shown in FIG. 5, a reinforcing ring 10 is integrally provided at the lower end of the reinforcing bar cage 8, and radial reinforcement is further provided by reinforcing bars 11 crossed in a cross shape.

On the other hand, a pair of tapered guide plates 6b are integrated with the tip of the push-in pipe 6 by welding or the like, and by pushing the guide plates 6b into the crossed portion of the reinforcing bar 11, the push-in pipe The tip end of the reinforcing bar cage 8 is removably positioned at the center of the lower part of the reinforcing bar cage 8 to prevent the reinforcing bar cage 8 from swaying.

With this configuration, the pushing force applied from the upper end of the pushing pipe 6 is received by the reinforcing bar 11, and the vicinity of the cross section of the reinforcing bar 11 serves as a pressure receiving part 12.

In addition, at the center of the inner side of the horizontal reinforcement 8b at the top of the reinforcing bar cage 8, as shown in FIG. A guide portion 13 is formed. The open end of the guide portion 13 on the side of the notch 9 is expanded, and a pair of spring portions 13a are formed protruding from the expanded base.

Therefore, by inserting the push pipe 6 into the guide part 13 through the notch part 9,
The push-in pipe 6 is held inside the guide part 13 by climbing over the spring part 13a and is held slidably in the vertical direction, so that the upper part of the push-in pipe 6 can also be attached to and removed from the center of the upper part of the reinforcing bar cage 8. is positioned.

Note that if the reinforcing bar cage 8 is heavy and cannot be held sufficiently by the guide portion 13, the reinforcing bar cage 8 may be temporarily fixed to the guide block 4 or the like with a rope, for example.

Next, a procedure for pushing the reinforcing bar cage 8 using the pushing device having the above configuration will be explained.

Immediately after completing the construction of the soil cement pillar 1, move the traveling trolley 2 to position it near the ground surface,
With the push-in pipe 6 standing upright via the leader, the reinforcing bar cage 8 is placed around the circumferential edge of the push-in pipe 6 through its notch 9, and then the guide plate 6b provided at the tip of the push-in pipe 6 is placed at the lower end of the reinforcing bar cage 8. By fitting into the receiving part 12 provided at the center and fitting and fixing the upper end outer periphery of the push-in pipe 6 into the inside of the guide part 13, the push-in pipe 6 is positioned at the center of the reinforcing bar cage 8. Hold 8. If the tip of the push-in pipe 6 is positioned at the center of the soil cement column 1 in this state, the setting is completed as shown in FIG. 1A, and the push-in standby state is reached.

Then, when the guide block 4 is immediately lowered along the leader 3 while applying vibration and impact using the vibrohammer 5, the push-in pipe 6 penetrates vertically into the soil cement column 1.

At the same time, the reinforcing ring 10 at the lower end of the reinforcing bar cage 8 is pressed by the tip of the push-in pipe 6 via the receiving part 12, and similarly penetrates the inner peripheral part of the soil cement column 1 concentrically and vertically.

At this time, the pushing force applied from the vibrohammer 5 to the reinforcing reinforcing bar cage 8 is transmitted from the upper end of the pushing pipe 6 to its tip, and then to the tip of the reinforcing bar cage 8 through the receiving part 12. Basket 8
This force causes the reinforcing bar cage 8 to be dragged into the soil cement column 1 from the tip side, so no force acts on the reinforcing bar cage 8 to cause it to buckle.

Also, in this state, the push-in pipe 6 is held by the insertion guide 7 provided on the lower side of the leader 3, and this insertion guide 7 is the position through which the notch 9 of the reinforcing bar cage 8 passes. During pushing, the pushing operation is not obstructed by the horizontal stripes 8b.

When the pushing operation is completed, both the pushing pipe 6 and the reinforcing bar cage 8 are buried inside the soil cement column 1, as shown in FIG. 1b.

In this state, the hardening of the soil cement column 1 is progressing, so even if the guide block 4 is pulled up and raised together with the push-in pipe 6, the reinforcing bar cage 8 will remain inside the soil cement column 1 due to its anchoring effect. Then, as shown in FIG. 1c, only the push-in pipe 6 is pulled out from the soil cement column 1 using the insertion guide 7 and the upper guide portion 13 of the reinforcing bar cage 8 as guides.

When the extraction is completed, the hardening of the soil cement column 1 has progressed considerably, so a cavity 1a corresponding to the cross-sectional shape of the push-in pipe 6 is formed in the center of the soil cement column 1, as shown in cross section in FIG. may be formed.

However, since this cavity 1a is not formed in a donut shape around the periphery of the reinforcing steel material as in the conventional case, it does not affect the adhesion between the soil cement column 1 and the reinforcing bar cage 8 in any way.

Therefore, the adhesion of the soil cement column 1 to the reinforcing bar cage 8 is ensured over the entire length in the depth direction, and a sufficient reinforcing effect can be obtained.

In addition, if an inclinometer is provided inside the tip of the pushing pipe 6 and the degree of inclination of the leader 3 is feedback-controlled according to the degree of inclination of the inclinometer, the pushing operation can be performed while maintaining the verticality with higher accuracy. I can do it.

Further, the means for pushing the pusher pipe 6 is not limited to the vibrohammer 5, but may be other means.

<<Effects of the Invention>> As explained in detail through the embodiments above, in the reinforcing reinforcing bar cage pushing device in the deep mixed compacted earth construction method according to the present invention, the pushing force applied to the pushing member is applied to the reinforcing bars. Since the pressure is applied to the reinforcing bar cage through the pressure receiving part and the reinforcing ring provided at the lower end of the cage, there is no pushing force that would cause the reinforcing reinforcing bar cage to buckle. The rebar cage is supported by the pushing member through the guide section, and the pushing member is slidably supported by the insertion guide fixed to the lower end of the leader. It can be pushed into position.

In addition, since the pushing member penetrates the center of the reinforcing bar cage, even if the pushing member is pulled out after pushing the reinforcing bar cage into the compacted soil, there is no effect on the adhesion between the reinforcing bar cage and the compacted soil. It is possible to effectively and reliably exhibit the reinforcing effect of the consolidated soil by the reinforcing bar cage.

[Brief explanation of drawings]

Figures 1 a to c are explanatory diagrams showing the overall configuration of this invention device and the construction order using this device, Figure 2 is an enlarged perspective view of section A in Figure 1 a, and Figure 3 is Figure 1 a.
Fig. 4 is an enlarged perspective view of section C in Fig. 1a, and Fig. 5 shows the structure of the lower end of the reinforcing bar cage in section D in Fig. 1a and the relationship with the push-in pipe. FIG. 6 is a partial perspective view showing the structure of the upper end of the reinforcing bar cage in section E in FIG. 1a and the relationship with the push-in pipe. FIG. FIG. 3 is a cross-sectional view of the soil cement column with the pipe pulled out. 1...Mixed compacted soil (soil cement column), 3...Leader, 5...Vibrohammer, 6...Pushing pipe (pushing member), 7...Insertion guide, 8...Rebar cage, 9
...notch part, 10...reinforcement ring, 12...receiving part, 13...
Guide section.

Claims (1)

[Claims] 1. In a pushing device consisting of a reinforcing reinforcing bar cage inserted into mixed compacted soil before consolidation formed in soft ground, and means for pushing the reinforcing bar cage, the reinforcing bar cage has one end in the circumferential direction. A notch provided along the vertical direction, a reinforcing ring provided at the lower end of the notch, a pressure receiving part provided at the center of the reinforcing ring to receive pushing pressure, and a guide part provided at the upper end. The pushing means includes a pushing member that is detachably attached to the pressure receiving part and the guide part and that penetrates the center of the reinforcing bar cage and applies a pushing force to the upper end, and the pushing member that pushes the reinforcing bars through the pushing member. A leader that supports the cage vertically; and an insertion guide that is fixed to the leader so as to protrude from the lower part of the leader into the reinforcing bar cage through the notch and slidably supports the pushing member. This is a device for pushing reinforcing reinforcing bars in deep mixed compacted earth construction method.