JP2003261932A - Hollow pipe for construction of displacement control type sand compaction pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow pipe for constructing a compaction sand pile without causing the displacement on an existing building and a sand compaction pile construction method excellent in work execution efficiency. <P>SOLUTION: In this construction method, a process in which a hollow pipe is pulled out after the hollow pipe 10 has been inserted to a specified depth and a process in which the hollow pipe is again inserted, are repeated in turn until it reaches the ground surface, to construct the sand compaction pile in a soft ground. The hollow pipe 10 has a displacement control type shape which has such a shape that the front end of the hollow pipe 10 is slantly notched for instance to thereby, localize, in one side face direction, to increase in the diameter of the compaction sand pile formed when it is inserted again. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement control type compaction sand pile construction which concentrates the displacement generated due to the diameter expansion during compaction in one lateral direction and does not give the displacement to the side of the existing structure. The present invention relates to a hollow tube for use and a compaction sand pile construction method using the hollow tube.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 9 and 10, a compacted sand pile 12 is placed in a soft ground A such as a loose sandy ground or a highly water-contained viscous ground to remove the ground. There is a ground improvement sand pile construction method for improvement. In this ground improvement sand pile construction method, for example, after the hollow tube 10e is penetrated to a predetermined depth H, a step of pulling out the hollow tube 10e by an appropriate length and a step of re-penetrating the hollow tube 10e are sequentially performed. This is a compaction sand pile construction method in which the compaction sand pile 12 is constructed in the soft ground A by repeating the process until reaching the ground surface.

In the compaction sand pile construction method as described above, the displacement (arrow Z in FIG. 10) caused by the diameter expansion during compaction causes the above-ground structure 2 close to the ground improvement area 25.
2. It may adversely affect natural objects 23 such as trees and existing structures 26 such as underground structures 24. Therefore, for example, an empty hole or groove 21 is provided between the ground improvement area 25 and the existing structure 26 to absorb the displacement Z (21a in FIG. 10).

[0004]

However, since such holes and trenches 21 for hollow digging require a predetermined size and shape in width, depth and length, the ground improvement area 2
It is necessary to provide an area for measures between 5 and the existing structure 26. In this case, the range of the ground improvement area 25 may be limited. In addition, since the hollow hole and the groove 21 are close to the ground improvement area 25, there is a problem that the improvement effect of the ground improvement area 25 is weakened. Further, in addition to the compaction sand pile construction method, a separate step is required to attach holes and trenches 21 for digging, which makes the construction complicated and raises the construction cost.

Therefore, the object of the present invention is to improve the ground improvement area 2
5 is to provide a hollow tube for compaction sand pile construction that eliminates the problem of displacement that adversely affects the existing structure without providing an empty hole or groove between the existing structure 26 and the existing structure 26,
Another object of the present invention is to provide a compacted sand pile construction method which is excellent in construction efficiency and does not give a displacement to an existing structure.

[0006]

Under such circumstances, as a result of intensive investigations by the present inventors, the tip shape of the hollow tube is displaceable in one lateral direction due to the diameter expansion during compaction. It was found that if the hollow pipes are made to have a shape that allows them to be concentrated and one side surface is installed on the opposite side of the existing structure and then compacted, then the existing structure will not be displaced.
The present invention has been completed.

That is, according to the present invention (1), after the hollow tube is penetrated to a predetermined depth, a step of pulling out the hollow tube to an appropriate length and a step of re-penetrating the hollow tube are sequentially reached to the surface of the earth. The hollow tube used in the method for constructing compacted sand piles in soft ground, the opening shape of the tip of the hollow tube being formed at the time of re-penetration of the hollow tube. Provided is a displacement control type compaction sand pile forming hollow tube having a shape in which the diameter expansion of the compaction sand pile is concentrated in one side surface direction.

According to the present invention (2), in the hollow tube, the shape of the opening at the tip is such that the expanded diameter of the compacted sand pile formed when the hollow tube is re-penetrated is concentrated in one lateral direction. And a hollow tube body whose upper part is connected to a rotary drive and forced lifting device and whose lower part is rotatably fitted to the upper part of the hollow tube tip. A displacement control type compacted sand pile forming hollow tube is provided.

Further, in the present invention (3), the hollow tube is installed such that one side surface direction thereof is opposite to the existing structure, and after the hollow tube is penetrated to a predetermined depth, the hollow tube is not rotated or has a predetermined range. The process of pulling out the hollow pipe to an appropriate length while rotating the and the process of re-penetrating the hollow pipe are repeated sequentially until reaching the surface of the earth, concentrating the displacement in one side direction in the soft ground. A method for constructing compacted sand piles for producing compacted sand piles is provided.

In the present invention (4), the hollow tube is installed so that one side surface of the hollow tube is opposite to the existing structure, the hollow tube is penetrated to a predetermined depth, and then the hollow tube is rotated. The process of pulling out the appropriate length and the process of re-penetrating the hollow pipe are sequentially repeated until reaching the surface of the earth, and the displacement is concentrated in one side direction of the soft ground to form a compaction sand pile. It provides a sand pile construction method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A displacement control type compacted sand pile forming hollow tube in the first embodiment of the present invention (hereinafter, also simply referred to as "displacement control type hollow tube" or "hollow tube"). And the compaction sand pile construction method using this is demonstrated with reference to FIGS. FIG. 1 (A) is a schematic view of a displacement control type hollow tube of the first embodiment, (B) is an enlarged perspective view of the tip of (A), and FIG. 2 is a sand pile at the time of compaction. Fig. 4 is a diagram showing a diameter-expanded state, Fig. 3 is a diagram for explaining a compaction sand pile construction method using the displacement-controlled hollow pipe of this example, and Fig. 4 is a diagram showing the position of the diameter-expanded sand pile with respect to the displacement-controlled hollow pipe. It is a schematic diagram represented in the state seen from above.

Displacement control type hollow tube 1 of the first embodiment
Reference numeral 0 denotes a hollow tube that can be applied to a so-called compacted sand pile construction method that has been conventionally performed, and the upper portion of the displacement control type hollow tube 10 is, for example, a rotating device 13 and a forced lifting device 14
And a hopper 15 into which the sand pile material 19 is charged. The shape of the opening at the tip of the displacement control type hollow tube 10 is such that the diameter expansion of the compacted sand pile formed when the hollow tube 10 is re-penetrated is concentrated in one side surface direction.
In this example, the distal end 11 of the cylindrical hollow tube is notched obliquely, and the opening surface 16 of the distal end 11 faces one side surface direction (rightward direction in FIG. 1A) and obliquely downward. ing.

The opening surface 16 at the tip of the displacement control type hollow tube 10
In, the diagonal angle β is appropriately determined, but if the diagonal angle β is too large, the compaction effect decreases, and if the diagonal angle β is too small, the diameter expansion of the sand pile is concentrated in one side direction. However, the existing structure may be displaced. For this reason, it is preferable that the oblique angle β is appropriately set within a range of approximately 30 to 60 degrees.

Such a displacement control type hollow tube 10 is shown in FIG.
As shown in FIG. 3, the hollow tube 10 is formed with a notch 181 which is an opening on the peripheral surface on one side, and the peripheral surface plate 171 on the other side functions as a so-called pressing plate. After the hollow tube 10 is penetrated to a predetermined depth, the hollow tube 10 is pulled out by an appropriate length, and then the hollow tube 10 is re-penetrated,
The discharged sand pile material 19 is extruded in the direction indicated by the arrow. For this reason, the diameter of the compacted sand pile 12 is increased by one side surface 18
Therefore, the displacement p occurs in the direction of the side surface 18, and the displacement does not substantially occur in the direction of the side surface 17.

Next, a compaction sand pile construction method using the displacement control type hollow tube 10 will be described. First, the displacement control type hollow tube 10 described above is attached to one side surface 18 on the opening surface 16 side.
Is installed on the opposite side (rightward in FIG. 3) of the existing structure 26 (FIG. 3a). Next, the hollow tube 10 is rotated within a predetermined range to allow the tip 11 to penetrate until reaching a predetermined depth H (FIGS. 3b and 3c). Then, the step of pulling out the hollow tube 10 to an appropriate length (FIG. 3d) and the hollow tube 10
Re-penetrating step (Fig. 3e) is sequentially repeated while rotating in a predetermined range until reaching the ground surface, and the compacted sand pile 12
(Fig. 3f).

After the hollow tube 10 is penetrated to a predetermined depth H, the range of rotation of the hollow tube in the process of pulling out the hollow tube 10 for an appropriate length and re-penetrating the hollow tube 10 depends on the diameter expansion of the compacting sand pile. The displacement is in the direction of the other side surface 17, that is, the existing structure 26.
It is carried out in a range that does not substantially occur on the side. In this example, as shown in FIG. 4, it is rotated in one direction at an angle α, and although some displacement occurs on the existing structure 26 side, this amount of displacement hardly affects the existing structure 26. Since it does not exist, it is included in the meaning that no displacement has substantially occurred.
Whether or not the displacement has occurred can be confirmed by, for example, installing a displacement meter at each position indicated by a cross mark in FIG. The planar shape of the compacted sand pile of this example is obtained by stacking the contour shapes of 12a, 12b, 12c, ... Created continuously in the rotation range.

In the conventional compaction sand pile construction method, due to the expansion of the diameter of the sand pile during compaction, displacement was generated in all directions in the horizontal direction in the soft ground. According to the sand pile construction method, the compacted sand pile 12 is constructed by concentrating the displacement in the direction of the one side surface 18 in the soft ground (FIG. 3f). That is, according to the hollow tube of this example, the amount of displacement that has conventionally occurred is not reduced, but the direction of displacement is concentrated in a specific direction. And the problem of displacement to the existing structure can be solved. Further, the displacement to the existing structure 26 can be diminished without providing an empty hole or groove between the ground improvement area and the existing structure 26. Further, the work for providing the holes and the trenches for the hollow digging can be omitted, and the work efficiency is improved. In addition, it is possible to extend the ground improvement area to the vicinity of the existing structure, which was difficult in the past.

In the compacted sand pile construction method of the first embodiment, the hollow pipe is rotated within a predetermined range.
The present invention is not limited to this, and for example, the hollow tube may not be rotated, that is, the compacted sand pile may be formed without rotation. In this case, almost no displacement occurs on the existing structure side. The tip portion of the hollow tube may be manufactured as a separate member and attached to the tip portion of a conventional existing hollow tube. In the present invention, the shape of the opening at the tip of the hollow tube is not limited to the above-mentioned form, and various forms can be used. Of these, the main ones are exemplified below.

Displacement control type hollow tubes in the second to fifth embodiments of the present invention will be described with reference to FIGS. 5 to 8 are perspective views of the distal end portion of the displacement control type hollow tube in each embodiment. 5 to 8, the same components as those of FIG. 1B are designated by the same reference numerals, the description thereof will be omitted, and only different points will be mainly described.
That is, in FIGS. 5 to 8, the point different from FIG. 1B is the notch shape of the tip portion. The cutout portion at the tip has different cutout shapes, but in each case, the cutout portion is formed on the peripheral surface on one side of the hollow tube, and the peripheral surface on the other side is so-called. It functions as a holding plate.

The displacement control type hollow tube 10a according to the second embodiment shown in FIG. 5 is formed by cutting a side surface 18 of a cylindrical hollow tube substantially horizontally and, on the other hand, slightly lower than the center of the lower end 11. A notch is made upward from the portion from the other side 17, and the shape of the opening at the tip is a stepped shape formed by a horizontal cut 101 and a vertical cut 102. According to this displacement control type hollow tube 10a, the hollow tube 10
Since the opening 16 is formed on the peripheral surface on one side of a and the peripheral plate 171 on the other side functions as a so-called pressing plate, the sand pile material 19 discharged during the penetration at the time of compaction. Is extruded in the direction indicated by the arrow. Therefore, even in the case of the displacement control type hollow tube 10a of this example, the diameter expansion of the compacted sand pile is concentrated in the direction of the one side surface 18, and the same effect as that of the first embodiment is achieved. be able to.

The displacement control type hollow tube 10b according to the third embodiment shown in FIG. 6 is different from the displacement control type hollow tube 10a according to the second embodiment in that it is a displacement control type hollow tube. This is a point in which a plurality of slits 104 are formed on the peripheral surface plate 171 on the other side, which serves as a holding plate for 10a. Since the slit width of the slit 104 is not so large, there is no fear that the sand pile material will come out of the slit 104 at the time of compaction, and the peripheral plate 171 with the slit can sufficiently fulfill the function as a holding plate. it can. Therefore,
Also in the displacement control type hollow tube 10b of this example, the same effect as that of the second embodiment can be obtained.

The displacement control type hollow tube 10c according to the fourth embodiment shown in FIG. 7 is different from the displacement control type hollow tube 10 according to the first embodiment in that one side face 18 is provided.
A diagonally downward direction, and a horizontal cut from a portion slightly above the lower end of one side surface 18,
The shape of the notch at the tip is an opening 16 different from the opening at the lower end formed by the diagonal cut 105 and the horizontal cut 106.
That is the point. Also in the displacement control type hollow tube 10c of this example, since the peripheral surface plate 171 serves as a pressing plate that pushes out the sand pile material 19 from the opening 16, the same effect as that of the first embodiment can be obtained.

The displacement control type hollow tube 10d according to the fifth embodiment shown in FIG. 8 differs from the displacement control type hollow tube 10a according to the second embodiment in that it is a displacement control type hollow tube. 10d is the hollow tube tip 111 and the hollow tube body 11
It is composed of 0 and 0. That is, the hollow tube tip portion 111 is the displacement control type hollow tube 1 of the second embodiment.
The hollow tube main body 110 has an upper part connected to a rotary drive and a forced lifting device (not shown) and a lower part hollow. It is rotatably fitted to the upper part of the tube tip 111. For fitting the hollow tube tip portion 111 and the hollow tube body portion 110, a known method such as a method of fitting with a bearing, a fitting concave portion and a fitting convex portion can be applied. As a compaction sand pile construction method using such a displacement control type hollow tube 10d, it is installed so that the direction of one side surface 18 is the opposite side of the existing structure, and after penetrating to a predetermined depth, it is rotated. Hollow tube 1
The step of pulling out 0d to an appropriate length and the step of re-penetrating the hollow tube 10d are sequentially repeated until reaching the surface of the earth, and the displacement is concentrated in the direction of one side surface 18 in the soft ground to compact the sand pile. The method of creating can be applied. According to this method
Even if the hollow tube body 110 is rotated, the hollow tube tip 1
Since 11 does not rotate, the direction in which the displacement is concentrated due to the diameter expansion of the sand pile does not change. Therefore, also in the displacement control type hollow tube 10d of this example, the same effect as that of the above-described embodiment can be obtained.

As the opening shape of the distal end of the displacement control type hollow tube of the present invention, in addition to the shapes shown in FIGS. 1 and 5 to 8,
Examples of the cut include an oblique concave shape, an oblique convex shape, and an oblique indefinite shape. Further, the displacement control type hollow tubes 10a to 10c may be composed of a hollow tube tip end portion having an opening shape and a hollow tube main body section, like the displacement control type hollow tube 10d. In this case, the hollow tube distal end portion and the hollow tube main body portion may be rotatably fitted to each other or may be non-rotatably fixed.

[0025]

According to the displacement control type hollow tube of the present invention, the diameter expansion of the sand pile is concentrated in the direction opposite to the existing structure at the time of compaction only by applying the conventional compaction sand pile construction method. Compacted sand piles can be created. Therefore, the problem of displacement that adversely affects the existing structure can be solved without using a means such as providing a hollow hole or groove between the ground improvement area and the existing structure. Further, the compaction sand pile construction method of the present invention does not give a displacement to an existing structure,
Has excellent construction efficiency.

[Brief description of drawings]

1A is a schematic view of a displacement control type hollow tube according to a first embodiment, and FIG. 1B is an enlarged perspective view of a tip portion of FIG.

FIG. 2 is a diagram showing a diameter expansion state of a sand pile at the time of compaction.

FIG. 3 is a diagram explaining a compaction sand pile construction method using the displacement control type hollow tube of the present example.

FIG. 4 is a schematic view showing the position of the expanded diameter sand pile with respect to the deformation control type hollow tube as viewed from above.

FIG. 5 is a perspective view of a distal end portion of a displacement control type hollow tube according to a second embodiment.

FIG. 6 is a perspective view of a distal end portion of a displacement control type hollow tube according to a third embodiment.

FIG. 7 is a perspective view of a distal end portion of a displacement control type hollow tube according to a fourth embodiment.

FIG. 8 is a perspective view of a distal end portion of a displacement control type hollow tube according to a fifth embodiment.

FIG. 9 is a plan view around a ground improvement area to which a conventional compaction sand pile construction method is applied.

FIG. 10 is a vertical cross-sectional view showing a part of FIG. 9 in an enlarged manner.

[Explanation of symbols]

10, 10a-10d Displacement control type hollow tube 10e hollow tube 11 tip 12, 12a-12c Compacted sand pile 13 Rotating device 14 Forced lifting device 15 hopper 16 Opening surface 17 The other side 18 One side 19 Sand pile material 21 empty holes or trenches 25 ground improvement area 26 Existing structure 110 Hollow tube body 111 Hollow tube tip 171 peripheral plate A soft ground Z, p displacement

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Ishii             1-2-1 Taito, Taito-ku, Tokyo Fudoken             Inside the corporation F-term (reference) 2D043 CA04 CA06 DA05 DB02 DB03                       DB07

Claims (4)

[Claims] 1. A method in which a hollow pipe is penetrated to a predetermined depth, and then a process of pulling out the hollow pipe to an appropriate length and a process of re-penetrating the hollow pipe are sequentially repeated until reaching the surface of the earth, and soft ground The hollow tube used in the method for producing a compacted sand pile, wherein the opening shape of the end of the hollow tube is an expanded diameter of the compacted sand pile formed when the hollow tube is re-penetrated. Displacement control type compacted sand pile forming hollow tube characterized in that it is concentrated in one side direction. 2. The hollow tube tip portion, wherein the hollow tube has a tip opening shape that concentrates the diameter expansion of the compacted sand pile formed at the time of re-penetration of the hollow tube in one lateral direction. And a hollow tube main body part whose upper part is connected to the rotary drive and forced lifting device and whose lower part is rotatably fitted to the upper part of the hollow tube tip part. Item 1. A displacement control type compacted sand pile forming hollow tube. 3. The hollow pipe according to claim 1 is installed such that one side surface direction is opposite to an existing structure, and after the hollow pipe is penetrated to a predetermined depth, it is not rotated or rotated in a predetermined range. The steps of pulling out the hollow tube to an appropriate length and re-penetrating the hollow tube are sequentially repeated until reaching the surface of the earth, and the displacement is concentrated in one lateral direction in the soft ground to compact the sand pile. A method for constructing compacted sand piles, characterized in that 4. The hollow tube according to claim 2 is installed so that one side surface direction is opposite to the existing structure, and after the hollow tube is penetrated to a predetermined depth, the hollow tube is rotated while being rotated to an appropriate position. It is characterized in that the step of pulling out the length and the step of re-penetrating the hollow pipe are sequentially repeated until the surface of the earth, and the displacement is concentrated in one side direction of the soft ground to form a compacted sand pile. Compacted sand pile construction method.