JPH05125726A - Construction of pile with drain layer - Google Patents

Abstract

PURPOSE:To form a drain layer like gravel or the like between a pile and the surrounding ground, without public nuisances like vibrations or noises, by an extremely simple way. CONSTITUTION:A flexible cylinder bag 10, which is opened at the top and closed at the bottom, is inserted into an excavated hole 30 previously prepared in the ground G. A drain material 50 like gravels are charged between the bag 10 and the pipe hole 30 and a hardening material 60 like mortar cement is charged with pressure to expand the bag 10. In this way, the drain material 50 is forced to position at the wall side of pile hole 30 by the expansive force to form a drain layer 51 at the periphery of the pile P1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a pile used in construction and civil engineering, more specifically, it is free from pollution such as vibration and noise and forms a drain layer such as gravel between the pile and the surrounding ground. The present invention relates to a method for forming a pile with a drain layer that can be used.

[0002]

2. Description of the Related Art As is well known, when driving and constructing existing piles such as PC or PHC with joints by a hydraulic hammer, a diesel hammer, etc., a drain material such as gravel is packed around the jointed piles and the piles are driven. At the same time, a so-called knot pile method with a drain layer is known in which gravel is brought into the ground at the nodes of the pile and a drain layer is formed around the pile.

Such a construction method not only enhances the bearing capacity of the pile, especially the frictional force around the pile, but does not discharge the soil at all, and further, the pile and the volume of the drain material brought into the ground, and the action of compacting the surrounding ground. In other words, there is a ground improvement effect, in addition,
Since the drain layer formed around the pile serves as a drain during liquefaction and drains the pore water in the ground to the ground, it has an excellent effect of preventing the pile itself and the building on this pile from collapsing. It is an extremely excellent construction method.

However, because of the drawbacks of noise and vibration when driving the piles, the above-mentioned construction methods have become almost unusable in recent years, especially in urban areas. For this reason, except for some sites with good conditions, a drilling auger is used to excavate a pile hole in which an existing pile is buried, and cement mortar is injected into this pile hole, or soil cement is formed to form the existing pile. The so-called pre-boring method of installing in the pile hole is generally used.

However, compared with the above-mentioned construction method, there is less noise and vibration, but there is no ground improvement effect on the surrounding ground and no drain effect due to the drain layer, and it is necessary to treat the soil discharged due to excavation, and to support the piles. There are various problems such as diminished power.

[0006]

As described above, the former has various beneficial advantages, but on the other hand, there is a problem associated with pollution such as vibration due to driving, noise, etc.
While there was no pollution such as noise, there were problems such as performance and soil disposal treatment compared to the former. The present invention solves these problems of the prior art. The invention according to claim 1 is pollution-free, has a compacting action on the surrounding ground, and drains pore water of the ground around the pile. It is an object to provide a method for constructing a pile that can form a drain layer.

In addition to the above object, it is an object of the present invention to provide a method of constructing a pile with a drain layer in which the supporting force of the pile, especially the peripheral frictional force thereof, is increased.

[0008]

The above object of the present invention is to insert a flexible tubular bag body having an open upper end and a closed lower end into a preliminarily excavated pile hole. It has been found that a method of constructing a pile with a drain layer, which is characterized in that after the drain material is filled in between, the hardened material is press-fitted into the bag body and the bag body is inflated into a pile shape, this is effectively solved. It was

That is, a drain material such as gravel is filled between the deflated bag body and the wall of the previously drilled pile hole, and a hardening material such as cement mortar is press-fitted to inflate the bag body by the means. The expansive force pushes the drain material toward the pile hole wall side, thereby compacting the surrounding ground and forming a drainage drain layer between the pile body formed by the bag body and the surrounding ground.

Further, as in the second aspect of the present invention, a flexible bag integrally formed with a knuckle portion that expands to a diameter larger than the diameter of the bag body at every required interval in the lengthwise direction of the bag body. By using the body, the obtained pile becomes knot-shaped, so that the frictional force of the pile body with the ground can be easily increased and the support force of the pile body can be increased. The bag that can be used in the present invention is not particularly limited as long as it is flexible and has sufficient toughness to press hardenable material such as cement mortar into the bag.
For example, a non-woven fabric, a synthetic rubber film, a slightly water-permeable woven fabric, a synthetic resin film, or a laminate of these materials as required can be used.

In terms of shape, it may have a substantially constant diameter in the longitudinal direction of the bag, such as a cylindrical shape.
It may have at least one portion that expands to a diameter larger than the main diameter of the bag when expanded. For example, a taper pile shape having different upper and lower diameters, a bottom pile shape having a large diameter portion formed in the lower portion, and the like, as in the invention according to claim 2, at the time of expansion at every required interval in the length direction of the bag body. It includes various shapes such as a plurality of joints integrally formed that expand to a diameter larger than the main diameter of the bag body.

Furthermore, by inserting and installing a reinforcing material such as a reinforcing bar in the bag body in advance or after the bag body is expanded, a foundation pile for supporting a structure such as a building can be obtained. Also,
When the main purpose is to improve the ground, reinforcing materials such as reinforcing bars may be omitted, and only a hardening material such as cement mortar may be pressed into the bag to form a pile-shaped ground improving material. As the hardening material to be press-fitted into the bag body, in addition to commonly used cement mortar, fresh concrete or so-called soil cement in which cement or ground improvement agent is agitated and mixed in excavated soil can be used.

Gravel is normally used as the drain material to be filled between the pile holes and the bag body that have been excavated in advance. However, sand, gravel mixed with sand, slag, or the like may be used. The material is not particularly limited as long as it is a material having water permeability that allows it to be drained to the ground via the above.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in the drawings. First, the embodiment shown in FIGS.
It shows an example of a method of constructing a pile with a drain layer for the purpose of ground improvement. FIG. 1 shows a bag body 10 forming a columnar pile. The bag body 10 is made of a tough and flexible woven fabric, which is made by weaving chemical fibers such as nylon and polypropylene in the length and width to give some water permeability, and has a cylindrical shape with a diameter of 300 mm and a length of 5 m. In other words, it is a bag-like object whose bottom portion (lower end portion) is closed by binding or bonding.

The term "slightly water-permeable" as used herein means that water is permeable by pressure but fine aggregates such as cement particles or sand are impermeable. That is, when the hardening material 60 such as cement mortar described later is press-fitted into the bag body 10, the excess water contained in the hardening material 60 is permeated so that the hardening material 6
It is preferable to reduce the water ratio in 0 to increase both strength and curing rate.

However, the bag body 10 used in the present invention is not limited to the above bag body, and can be variously changed according to the type of the hardening material 60 to be press-fitted, the ground conditions, and the like. For example,
The material of the bag body 10 may be a non-woven fabric, a synthetic rubber film, a slightly water-permeable woven fabric, a synthetic resin film, or a laminate of these materials as necessary. Various lengths and the like can be formed as required.

2A to 2D are conceptual views showing a process of constructing a pile with a drain layer using the bag body 10, which will be described below in order. FIG. 2a shows a process of excavating the pile hole 30 in the ground G with the excavation auger 20, for example, a diameter of 300 m which is substantially the same as the inflated shape of the bag body 10.
A pile hole 30 having a depth of 5 m and a depth of 5 m is excavated. In addition, since the size of the diameter of the pile hole 30 determines the filling amount of the drain material 50 to be described later, and ultimately the thickness of the drain layer 51, the drainage performance of the drain material 50 and the soil quality of the ground G. It is preferable to determine the pore size in consideration of the above.

FIG. 2b shows a state in which the bag body 10 is inserted and installed in the pile hole 30 with the insertion rod 40.
Install so that the bottom part of is firmly pressed against the hole bottom. Alternatively, as shown in FIG. 3, instead of the insertion rod 40, a disk-shaped concrete block 41 or the like having a diameter of 200 to 250 mm is previously inserted into the bottom of the bag body 10, and the block 4 is inserted.
The bag body 10 itself may be inserted and installed in the pile hole 30 using the weight of 1.

Then, as shown in FIG. 2c, a drain material 50 such as gravel is filled around the bag body 10, that is, between the bag body 10 and the peripheral wall of the pile hole 30. When the drain material 50 is filled, the insertion rod 40 is vibrated while the insertion rod 40 is still inserted in the bag body 10, and
When the above is charged, the drain material 50 can be filled between the bag body 10 and the peripheral wall of the pile hole 30 without any gap.

When the bag body 10 is installed and the drain material 50 is filled in this way, the upper opening of the bag body 10 is set to the hardening material pressure inlet M of the compressor (not shown) as shown in FIG. 2d.
, And a hardening material 6 such as cement mortar in the bag body 10.
0 is press-fitted and the bag body 10 is expanded to a required size to form a desired pile body P1. Here, the press-fitting of the hardening material 60 differs depending on the strength of the ground G and the bag body 10, but, for example, 5
Press-fit in the range of -30 kg / cm ² . In such press-fitting, the expansion of the bag body 10 can be controlled by the press-fitting amount and the press-fitting amount of the hardening material 60. Further, as shown by an imaginary line in FIG. 2d, by fitting a cylindrical protective holder H to the upper opening of the pile hole 30 to protect the opening edge of the pile hole 30, the head of the pile body P1 is It is preferable to prevent abnormal expansion.

Thus, in the process of forming the pile P1,
Drain material 50 filled between the bag body 10 and the peripheral wall of the pile hole 30
Is pushed toward the peripheral wall of the pile hole 30, and the peripheral ground G of the hole wall is compacted by the pressure while expanding the diameter of the hole wall. Also, since the drain layer 51 itself is compacted by the pressure,
The pile body P1 formed by the bag body 10 and the hole wall ground G can be firmly connected, and the pore water in the ground G can be drained to the ground through the gap between the drain members 50.

In addition, since the pile with the drain layer constructed in this embodiment is mainly intended for ground improvement, the reinforcing material such as the reinforcing bar inside the pile body P1 is omitted. Further, as the hardening material 60 press-fitted into the bag body 10, so-called soil cement or the like in which mortar or soil containing super-poor mixture and a solidifying agent such as cement are mixed can be substituted. In particular, when soil cement is used as a substitute, the excavated soil from the pile hole 30 can be used as it is, so that not only the cost is reduced, but also the soil disposal process is unnecessary.

Further, the drain material 50 filled between the bag body 10 and the peripheral wall of the pile hole 30 is not limited to the above-mentioned gravel, and
Sand, gravel mixed with sand, or slag can be used instead. In selecting the drain material 50, the soil quality of the ground G, the possibility of liquefaction and the degree thereof are taken into consideration. Next, the examples shown in FIGS. 4 to 5 show an example of a method of constructing a pile with a drain layer for a foundation pile.

FIG. 4 shows a bag forming a noded pile in which a knotted portion 11 that expands to a diameter larger than the diameter of the bag 10 is integrally formed at every required interval in the lengthwise direction of the bag 10. Body 10
An example is shown. This bag body 10 is made of the same material as that of the first embodiment, and has a cylindrical body having a diameter of 400 mm and a length of 8 m, and has a diameter of a predetermined interval in the length direction (for example, 1 m intervals). It is formed by integrally providing a doughnut-shaped node portion 11 having a width of about 450 to 500 mm and a width of about 200 mm, and the lower end portion (bottom portion) is closed by binding or bonding.

Similar to the first embodiment, after the pile hole 30 having a diameter of 400 mm and a depth of 8 m is excavated in the ground G by the excavating auger 20, the bag body 10 is inserted and installed in the pile hole 30 by the insertion rod 40 (see FIG. 5a-b). Then, as shown in FIG. 5c, after inserting the reinforcing member 70 such as a reinforcing bar into the bag body 10, the insertion rod 40 is pulled out. The reinforcing material 70 has an outer diameter 2 obtained by subtracting the covering thickness (at least 60 mm) of the hardening material 60 described later.
Therefore, a reinforcing bar having an outer diameter of 80 mm or less, for example, an outer diameter of 250 mm, H-shaped steel, or a steel pipe having a large number of punched peripheral surfaces is used. Further, either the insertion of the reinforcing material 70 or the extraction of the insertion rod 40 may be performed first.

Thereafter, as shown in FIG. 5c, the bag body 10
And a drain material 50 such as gravel between the peripheral wall of the pile hole 30 and
Next, as shown in FIG. 5d, the upper opening of the bag body 10 is connected to the hardening material pressurizing port M of the compressor, and the hardening material 60 such as cement mortar is press-fitted into the bag body 10 to form the bag body 10 and this bag body. Inflate the knot 11 provided integrally with 10,
A desired pile body P2 is formed.

In this embodiment, a node-pile is formed in order to increase the supporting force, particularly the frictional force on the peripheral surface, and a reinforcing material 70 such as a reinforcing bar is inserted for the main purpose of constructing a foundation pile. Although different from the first embodiment in the point, the forming process is substantially the same as described above. Of course, the present invention is not limited to the two embodiments described above, and various modifications can be made as necessary. For example, a reinforcing material 70 such as a reinforcing bar can be inserted into the first embodiment to form a foundation pile, and the bag body 10 can be molded freely, so not only the node pile of the second embodiment but also the pile bottom. It is also possible to make expanded piles that expand only the chisel, and deformed piles such as tapered piles that have a diameter that increases toward the pile head.

[0028]

Since the present invention is constructed as described above, it has the following effects. According to the method for forming a pile with a drain layer according to claim 1, there is no pollution such as vibration and noise by a very simple method, and a drain layer such as gravel is formed between the pile and the surrounding ground. There is an effect that can be.

That is, the drain material is filled between the bag body before expansion and the excavation hole, and the hardening material is pressed into the bag body to expand the hole wall, thereby compacting the surrounding ground, To form a drain layer such as gravel that drains pore water in the ground to the ground, and also to increase the frictional force of the pile body formed by the bag body by the compaction action of the ground, and to increase the bearing capacity. You can

Further, by using the noded pile as in the second aspect of the present invention, in addition to the above effects, the supporting force of the pile body, particularly the peripheral frictional force thereof, can be increased.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration of a bag according to a first embodiment.

2A to 2D are conceptual diagrams showing a forming process of the first embodiment.

FIG. 3 is an enlarged view of an essential part showing another embodiment of the first embodiment.

FIG. 4 is a front view showing the configuration of a bag according to a second embodiment.

5A to 5D are conceptual diagrams showing a forming process of the second embodiment.

[Explanation of symbols]

 G Ground H Protective holder M Compressor hardening material inlet for compressor P1, P2 Pile body 10 Bag body 11 Node section 20 Excavation auger 30 Pile hole 40 Insert rod 41 Concrete block 50 Drain material 51 Drain layer 60 Hardening material 70 Reinforcing material

Claims (2)

[Claims] 1. A flexible tubular bag having an open upper end and a closed lower end is inserted into a previously drilled pile hole, a drain material is filled between the bag body and the hole wall, and then a hardened material. A method for constructing a pile with a drain layer, which comprises press-fitting a bag into a bag and inflating the bag into a pile shape. 2. The drain layer according to claim 1, wherein a node portion that expands to a diameter larger than the diameter of the bag body is integrally formed at a required interval in the lengthwise direction of the bag body. How to create a pile.