JP2000170149A - Forming method for underground pile and equipment therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict ground subsidence or liquefaction during earthquake by filling up the bore hole of a pile with a material frown the top while forming a columnar bore hole for pile by pressing in a shoe into ground with a rod, pulling out the rod while giving reciprocating motions to the rod in a state of leaving the shoe at the bottom of pile with a predetermined depth thereby forming a pile column with a filling material. SOLUTION: For forming an underground pile 1, a pushing pressure (rotating force) 6 is applied to the rod 3 thereby pushing in a shoe 2 at the tip of the pile, giving reciprocating motions while pulling out the rod 3, and filling materials 4 including crushed stone, concrete, slag or the like inside the underground bore hole 1 are compacted. And when the shoe 2 is pressed to a required position, the shoe 2 is separated from the rod 3 and left at the bottom of pile. Also, the shoe 2 is pressed together with the materials 4 in one united body, and bore hole of pile 8 created at this time is immediately filled up with the materials 4 continuously, thereby preventing the collapse of the wall 9 of the bore hole of pile and also preventing segregation of the materials 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foundation for structures and buildings, a foundation for roads, railways and runways, a foundation for levees, and a foundation for forming piles made of crushed stone, concrete, or mine pits in the ground. The present invention relates to a method and an apparatus for forming an underground pile for performing construction and landslide prevention work.

[0003]

2. Description of the Related Art Conventionally, when newly constructing land for a house, a store, a factory, and an office, a lot of land in the soft alluvial world is often developed, and many soft ground countermeasures have been considered since ancient times.
It has also been implemented. This countermeasure focuses on the fact that the ground is composed of gaps between soil particles (solid) and groundwater (liquid) or air (gas) (the possibility of compaction is indicated by relative density). The basic idea of each method is two methods of solidifying the skeleton between the soil particles or solidifying the gap using a bonding material or an adhesive. In addition,
Water occupies mainly the gaps in the soft ground where the groundwater level is high.
For each method, the "Foundation Design and Construction Handbook" and "Soft Ground Handbook" issued by the Construction Industry Research Committee are classified by function and described. The features of each method are as follows.

[0004] In other words, the replacement method has high reliability since it is replaced with high-quality soil, and has a long track record since ancient times, but has difficulty in treating construction-generated soil to be eliminated.

Although the compaction method has a great effect of suppressing settlement and preventing liquefaction during an earthquake, it is difficult in terms of environment such as vibration and noise during construction applied to a neighborhood.

In the cast-in-place pile method, a large hole diameter is surely reached to the support layer by mechanical excavation, so that a large pile supporting force can be obtained in the same manner as the existing pile method. Hole bottom processing such as protection and removal of precipitates is complicated, and quality control of shapes and materials is difficult, such as separation of materials due to groundwater or muddy water in the holes when filling concrete.

Also, the consolidation method is applied in a wide range of fields as ground improvement for various constructions, since a hardened material can be injected into a limited area with high accuracy and the work can be performed without noise and vibration. In addition, it is difficult to select a hardening material suitable for the ground and to confirm the effect of improvement, the construction cost is high, and attention must be paid to groundwater contamination.

[0008] The forced consolidation method forcibly compresses the ground to increase the strength of the soil as well as the consolidation action. The loading method of this method has a static load and a dynamic load. The static load requires a long period of time until the end of compaction, and the dynamic load has difficulty in vibration and impact noise during operation, and variations in the compaction effect. .

In the dewatering method, soil water in a clay layer is dewatered in order to promote consolidation of the ground. However, there are problems in workability such as clogging and continuity of drain materials in the ground, and theoretical problems. It is difficult to select the complex soil conditions of the original ground necessary for the analysis, and to match the prediction and implementation effects based on it.

In each of the above-mentioned methods, based on the important Coulomb's formula of soil mechanics, the same equation shows the shear strength (τ) as τ = c + σ * tanφ, where c is the adhesive strength,
φ is the shear resistance angle and σ is the direct pressure.
Is large and φ is small. Sandy soil is opposite and is affected by σ. This simply shows the difference between countermeasures for cohesive soil and sandy soil, and many of the above-mentioned construction methods are uniform and limited to the target soil, and complex and uneven soft ground In the stratum, the construction accuracy varies. Further, Japanese Patent Publication No. 03-24925 related to the above-mentioned publication discloses a technique of a method of forming an underground columnar body using a semi-permeable cloth, but this means requires a complicated work process. It is difficult to confirm the stability of the drilled hole and the solidification state of the hardened material. on the other hand,
In the foundation work for houses and small structures, the construction environment, which is the working environment, is narrow even if there is insufficient knowledge of the ground or knowledge of uneven settlement of the foundation or liquefaction of the ground during an earthquake. What In addition, due to the treatment of construction waste such as mud generated by construction work and the waste liquid caused by the injection of hardening material, and the restrictions and restrictions on noise, exhaust gas, and vibration of construction machinery, foundation work is not performed without sufficient ground measures. The above-mentioned buildings and the like have suffered a great deal of damage due to deformation of foundations and sliding failure due to insufficient ground support capacity.

[0011]

[0012]

There are various countermeasures for soft ground as described above. However, since it is not possible to cope with a complicated and uneven ground layer of soft ground widely, it is necessary to carry out prediction investigation, theoretical analysis, hardening material injection, Various examinations such as confirmation of improvement effects and countermeasures for troubles during construction are required, and construction machines and experienced technicians are specified. As a result, the construction period becomes longer and construction costs become higher.

Further, in terms of the environment, there are many problems such as treatment of construction soil, treatment of waste liquid and muddy water in addition to vibration and noise of construction machines.

On the other hand, in the case of construction work in a residential area, in addition to the above-mentioned restrictions, there are problems such as securing a transportation route for large machines and a work space, exhaust gas, etc., and construction is not possible while requiring countermeasures for foundations. There are many issues. In the present invention, since the construction cost is low and the method is highly versatile, it is possible to easily increase the bearing capacity of the original ground and to suppress land subsidence and liquefaction during an earthquake. That is, after paying attention to the relative density of the original ground and grasping it, press the shoe at the tip of the original ground into the original ground via a rod. Pile holes created by press-fitting (consolidation) must be filled with the necessary materials for ground reinforcement, forming the pile and making the original ground solid. Also, the wall of the pile hole (hole wall) generated by press-fitting
Immediately and evenly fill the pile holes with material without gaps,
To prevent the collapse of the hole wall by balancing the earth pressure acting on the pile hole wall with the filling material. In the conventional cast-in-place pile method, this process is an important management item,
Since this trouble was the biggest disaster, it required the placement of experienced technicians. However, it is necessary to eliminate these troubles and to ensure work safety and simplify the process.

[0015] Furthermore, in order to promote the compaction of the ground, a highly permeable material such as crushed stone is used as a filling material, and groundwater is easily removed by utilizing the permeability of an underground pile. Also, the shoe at the tip of the pile should maintain the shape of the underground pile and the bearing capacity of the tip, and at the same time maintain the direction of press-fitting. Furthermore, to reduce the press-in resistance of the stake and to reduce the press-in force of the rod. Pressing work should be performed continuously in consideration of soil thixotropy. It is another object of the present invention to provide a highly efficient and inexpensive underground pile forming method and apparatus having an advantage that the ground support force after forming by this method can be easily measured by an existing simple loading test or the like.

[0016]

[0017]

SUMMARY OF THE INVENTION In order to achieve the above object, a method of forming an underground pile according to the present invention is as follows. First, a shoe is pressed into the ground with a rod to form a columnar pile hole. The material is filled from above the pile hole to prevent the collapse of the pile hole, and when the shoe reaches a predetermined depth, the rod is reciprocated while leaving the shoe at the bottom of the pile. The method is characterized in that the material is pulled out while squeezing the material sequentially from below, and a pile pillar made of the filling material is formed in the ground.

A second feature is that a slide tube is connected to a rod for press-fitting the shoe at an arbitrary position on the rod shaft so that the rod can reciprocate.

Third, pile columns are formed by selecting materials such as crushed stone, concrete, mine tailings, recycled aggregate, and drain materials, and the pile columns are integrated with a support pile, a friction pile, and an original ground. The feature is that the design form of composite ground and drain piles can be selected.

In the fourth formed pillar, the material is filled from above while re-pressing the shoe with a rod to form a pile hole.
A step of forming an underground pile having a larger diameter at the top than at the bottom,
The process is repeated to form a multi-stage underground pile having a diameter gradually increasing from below.

Further, the underground pile forming apparatus of the present invention comprises:
A shoe is detachably provided at the tip of a rod that is press-fitted, and a supply device for supplying material is provided above a pile hole formed by the shoe, and a material is supplied to the pile hole while forming the pile hole. It is characterized by supplying and forming underground piles. Second
A lead device configured to prevent collapse of a pile hole mouth by a sheath tube having a material supply port attached thereto, and to fix a clinometer to the sheath tube, further attach a support stand, and maintain a press-fitting angle of the pile. It is characterized by having been provided.

Third, a slide tube having a projection or a screw attached thereto is connected to an arbitrary position on a rod shaft.

Fourth, the protrusion of the shoe is formed in a conical surface, and a guide is attached to the outer periphery of the shoe.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. The embodiment shown in FIGS. 1 to 3 shows a method and an apparatus for forming an underground pile. FIG. 1 shows a method and an apparatus for forming an underground pile. In order to form the underground pile 1, a pressing force (rotational force) 6 is applied to a rod (rod) 3 and a shoe ( While the shoe 2 is being pressed in, the rod 3 is reciprocated while being pulled out, and the material 4 to be filled into the underground pile 1 is compacted. When the shoe 2 is press-fitted to a required position while maintaining the shape of the underground pile 1, it is separated from the rod 3 and remains at the pile bottom.

Further, the shoe 2 is press-fitted integrally with the material 4, and the pile hole 8 formed at this time is immediately filled with the material 4 immediately to balance the earth pressure to prevent the collapse of the pile hole wall 9. Separation of the material 4 can be prevented.

The hopper 5 for supplying the material 4 has the material 4
The structure is designed to promote the flow and prevent scattering of the stakes, and can be attached to and detached from the stakes.

That is, the underground pile 1 is provided with a shoe 2 at the tip of the pile, the shoe 2 is press-fitted with the rod 3, and the material 4 is inserted into the formed pile hole 8.
Can be poured and compacted. The feature is that it can be easily formed even with a complicated and uneven soft ground layer or irregular support layer by properly maintaining the cross-sectional shape, length and approach angle of the pile in the ground. I have. In this case, a device for automatically controlling and finishing a desired pile while sensing the operating state of the above-mentioned bar 3, shoe 2, material supply device 5, etc., and checking the formation state of the underground pile 1 via a detection mechanism. It may be.

In the illustrated example, the material 4 is an underground pile 1 using crushed stone. According to this, since the groundwater is mainly removed from the soil structure to secure the volume of the pile, There is no dirt or earth and sand generated by the formation of the middle pile 1, and various countermeasures and costs associated with the treatment of the construction soil that have been required so far are not required, and the work site is also used as the generated soil. The work environment is sanitary without contamination. In addition, the material 4 to be filled can be similarly performed by appropriately selecting concrete, mining tail, or the like in addition to the above, depending on construction conditions.

FIG. 2 shows the structure of each shoe which can be mounted on the tip of the pile. FIG. 2A shows an example of a shoe 2 used for ordinary soft ground. The shoe 2 has a protruding portion formed in a circular and sharp conical shape 2a, and is provided with an insertion / removal hole 2b and a hook 2c so as to be detachably supported including a press-fitting rod (rod) 3 and temporary holding. . This allows the shoe 2 to be pressed into the rod 3 so as to follow the rod 3, so that the structure is simple and suitable for use on ordinary soft ground. FIG. 2B shows an example in which the protruding portion of the shoe 2 is formed into a sharp square 2d. When the shoe 2 rotates, the action of a drill is used to consolidate the pile tip ground. It can be used for harder ground than the above.

FIG. 2 (C) shows that the shoe 2 shown in FIGS. 2 (A) and 2 (B) is provided with a ridge 2e for intrusion, that is, a screw to act as a screw to facilitate entry into the ground. Here is an example of what can be done. The shoe 2 can be suitably used for a soil layer partially containing hard soil, or for a ground with a lot of sand or silt where the above-mentioned shoe 2 tends to idle. FIG. 2 (D)
Is to connect a cylindrical guide plate 2f to the shoe 2 shown in FIGS. 2 (A), 2 (B) and 2 (C) so as to appropriately maintain the press-fitting angle of the shoe 2 and suppress the hole runout. Here is an example of what can be done. According to this, it can be suitably used especially for the inclined pile 1b described later.

As shown in FIG. 2E, when the underground pile 1 holds a core material 11 such as a reinforcing bar, the shoe 2 and the rod 3 are used.
It is preferable to provide a metal fitting 10 on which the core material 11 such as a reinforcing bar can be fixed. At this time, the rod 3 has a structure in which the support portion 3a is loosely fitted so that the metal fitting 10 does not rotate together.
It is good to provide the ring part 10a which can be suspended. On the other hand, when rotation is not required for press-fitting, the metal fitting 10 may be fixed to the shoe 2. By leaving the metal fitting 10 in the pile hole 8 as in the case of the shoe 2, it is possible to efficiently manufacture and construct a reinforced concrete pile or the like in which the tensile strength and bending strength of the underground pile 1 are increased by a simple construction method.

According to the above method and apparatus, the shoe (shoot) 2 can be selected widely according to construction conditions such as various soil types and slanted piles, and underground by optimal hole formation under various conditions. The pile 1 can be formed. That is, the rod 3 and the shoe 2 are detachable by the temporary holding mechanism, and the shoe 2 is left at a predetermined depth to secure a stable tip support force 7a described later. Then, the shoe 2 is press-fitted with a rod (rod) 3 and the material 4 is poured in one piece and squeezed to form the underground pile 1, so that the shape of the pile and the material 4 to be filled are arbitrarily adopted according to design conditions. Since it is possible to use recycled aggregate or mining tails using industrial waste as the material 4, it is possible to use a highly versatile construction method such as promoting the use of recycled resources and reducing construction costs.

Further, the pressing force 6 of the rod 3 to be press-fitted is calculated from the reaction force of the tip shoe 2 in direct contact with the ground 7 and the frictional resistance with the material 4 in contact with the outer peripheral surface of the rod 3 which increases with depth. You. The reaction force and the resistance force are reduced by using the effect of the shoe 2 and the frictional resistance of the rod 3 as dynamic frictional resistance. Therefore, the pressing force 6 is small because the diameter of the rod 3 is small.
It mainly depends on the diameter of the shoe 2 at the tip of the pile. Accordingly, the construction can be performed with smaller power than the conventional casing method, and efficient and stable pressing operation can be performed using a small machine with low noise, low vibration.

FIG. 3 shows an example of an apparatus for solving the case where the material 4 is closed in the pile hole 8 due to the intermeshing or stickiness of the particles and the continuous filling of the material 4 becomes impossible.

3A, the closed state of the material 4 is broken by attaching the projection 3a to the rod 3 and reciprocating the closed state in the pile hole 8 so that the rod 3 moves. Thus, the material 4 can be smoothly injected, and at the same time, the structure can be easily pressed by the projections 3a by the operation of pulling out and inserting. This operation can be performed as needed at the time of press-fitting or at the time of pulling out the rod 3.

FIG. 3 (B) shows the rod 3 having projections 3b symmetrical to the top and bottom, so that the material 4 is directed toward the pile hole wall 9 while breaking the closed state of the material 4. In this structure, the pile hole wall 9 is made to adhere to stabilize. FIG.
(C) is a slide tube 1 in which a screw portion 12b is provided in a tube 12a to stir the material 4 to break a closed state.
2 shows an example. The slide tube 12 is prepared on site,
When the rod 3 enters and the amount of the material 4 to be injected is abnormal during the press-fitting operation, the slide tube 12 is immediately inserted into the rod 3 and a pressing operation such as rotation is applied to the slide tube 12 to apply the material 4. The closed state is broken to promote the injection of the material 4. In this case, the slide tube 12 may be removed after confirming the injection condition.

FIG. 4 shows a process of forming an underground pile using the apparatus shown in FIG. First, decide the construction position of the pile,
Next, the hopper 5 of the material supply device for assisting the positioning and filling of the material is set as shown in FIG. Next, the shoe 2 is placed and a bar 3 is attached as shown in FIG. Then, as shown in FIG. 2C, the bar 3 is operated to press-fit the shoe 2. At this time, the material 4 is put into the pile hole 8 formed by press fitting.
To prevent the collapse of the pile hole wall 9 and the separation of the material 4.

Then, as shown in FIG. 3D, the rod 3 reaches a predetermined position (depth) or recognizes the predetermined press-fitting by means of detecting a predetermined press-in reaction force, and the operation is completed. Next, since the connection with the shoe 2 is separated by lifting the rod 3, the shoe 2 is left at the tip of the pile bottom in the pile hole 8. In this state, when the bar 3 is reciprocated while being pulled out as shown in FIG. 7 (E), the bar 3 squeezes the material 4 sequentially from below, directs the material 4 to the pile hole wall 9 side, makes the material 4 stick, and piles The hole material 9 is stabilized, and the dense material 4 is obtained. As a result, the material 4 is densely formed over the entire length in the pile hole 8 as shown in FIG.

By the above means, the underground pile is formed with high precision and high performance in section and length and has stable pile supporting force, and at the same time, the filling material of the pile makes the soft ground solid, so the ground supporting force is increased. It can be easily increased. Since the work process is simplified and the work is performed continuously, the construction period can be shortened, and at the same time, the underground pile can be easily formed at a safe and low construction cost.

FIG. 5 shows an example of an underground pile according to a classification example based on a conventional soft ground countermeasure, in order to facilitate the study in planning and designing the underground pile. It is. FIG. 5A shows an example in which the underground pile 1 reaches the support layer 15 and is designed as a support pile. In this case, negative friction due to land subsidence acting on the underground pile periphery 9
Consider a.

FIG. 5B shows a design example of a friction pile supported by the tip support force 7a of the underground pile 1 and the ground friction force 7b on the outer surface of the underground pile.

FIG. 5 (C) shows that a large number of underground piles 1 are provided in a range where ground improvement is required, and the filling material 4 of the underground piles 1 having properties different from those of the original ground 7 is used as the surrounding ground. The design example which forms the area | region 13 of the composite ground by artificially integrating with the ground 7 is shown. According to this, it is possible to design a composite ground for the purpose of making the original ground 7 dense, increasing the ground support capacity, and suppressing land subsidence and liquefaction during an earthquake.

FIG. 5 (D) shows that the underground pile 1 is made of a highly permeable packing material 4 in order to promote the compaction of the original ground 7, and a drainage facility 4a is provided at the top of the pile. 7 shows a design example of a drain pile for eliminating groundwater from the underground pile 1.

According to the above classification, the underground pile 1 according to the present construction method can be widely applied to the basic design because the existing theoretical analysis can be used. In addition, there is an advantage that the quality control after the pile is formed can be confirmed by a simple loading test or the like. Therefore, this construction method is a highly versatile construction method that is adaptable from ground improvement work using a large-scale large-scale construction machine to foundation work for small-scale ordinary houses and manual construction according to the work environment.

FIG. 6 shows an example of an embodiment for increasing the strength of an underground pile. FIG. 6A shows an example in which the underground pile 1 is formed using a reinforcing bar as the core material 11. That is, the metal fitting 10 is set on the shoe 2, the rod (rod) 3 is set, and the metal fitting 1 is set.
The core material 11 of the reinforcing steel is inserted and press-fitted simultaneously while holding the core material 11 of the reinforcing steel in the inside and supporting them integrally, but the core material 11 of the reinforcing steel is tightly connected to the stirrup 11a in accordance with the press-fitting.
To form a series of cores 11.
At this time, it is preferable to form the underground pile 1 while supplying the filling material 4 such as concrete together with the core material 11, whereby the tensile strength and the bending strength can be increased as desired. FIG. 6B shows a usage example in which steel pipes 14 are used as the core material 11, and a pipe tip 14 a of the steel pipe 14 or the like has a shoe 2 and a rod 3.
The bar 3 has a structure similar to that of the above-mentioned reinforcing metal fitting 10 so as not to hinder the attachment / detachment of the steel bar.
And

On the other hand, the steel pipes 14 may be fixed to the shoe 2 and the work process may be omitted in place of the rod 3.
The inside of the tube is filled as needed.

FIG. 6C shows an example of forming a multi-stage underground pile having different diameters. That is, after the lower-stage underground pile 1 is formed to a predetermined position, the shoe 2 is press-fitted into its head to enlarge the diameter of the pile. In addition, the diameter of the shoe 2 is free, and this step may be repeated when forming the underground pile 1 in multiple stages.

Thus, the pile supporting force and the bending strength of the pile head and the strength of the horizontal force can be easily enhanced.

FIG. 7 shows a work in a place having a water surface such as the sea, a work in a peat layer (peat layer) zone or a very soft ground in a sludge layer, or the like, in which the shoe sinks in the above-mentioned method. It is an embodiment showing a suitable construction method when a material cannot be stably input. That is, as shown in FIG. 7 (A), the shoe is attached and supported in a temporary holding state by a hanging tool (temporary holding mechanism) 2g comprising means shown in FIG. 2. A guide tube 16 accommodating the material 4 is set in parallel, and the whole is moved to a lifting position by a hanging rope 16a such as a crane, and positioned.

Next, as shown in FIG. 7B, when the guide tube 16 integrated as described above is lowered together with the shoe 2, the mud soil sinks by its own weight. Also, the guide tube 16
Has a structure in which the material 4 can be continuously poured from above as shown.

Next, as shown in FIG.
The hook 2g of the shoe 2 attached to the shoe 6 is released by any means such as cutting, and a rod (rod) 3 is operated to start the press-fitting of the shoe 2 and continuously supply the material 4 of the underground pile 1. While reaching the predetermined depth. 4E and 4F, the material 4 is tamped to form the underground pile 1, and the rod 3 and the guide tube 16 are removed as shown in FIG. 7D. Finish the work. In addition, as for the illustrated example of the temporary holding of the shoe 2,
g can be integrated with the guide tube 16 by a rope or the like using the hook 2c of the shoe 2, and can be moved by a crane or the like.

Accordingly, the construction method of the present invention enables the underground pile 1 made of these materials to be formed extremely easily, efficiently, and at low efficiency even in the sea where it is difficult to form the underground pile 1 using crushed stone or concrete. It is possible to make it into cost.

Next, with reference to FIG. 8, one working example when forming the inclined pile 1b according to another embodiment of the present invention will be described. That is, the leading device 17 for the countermeasure against the pile hole at the place of the guide tube 16 of FIG.
a, the material supply port 17b, the press-fitting angle and the leading device 17
And a slope 17d for controlling the press-fitting angle.

The procedure for constructing the inclined pile 1b using the leading device 17 is as follows. First, the shoe 2 shown in FIG.
Then, after the sheath 2 and the shoe 2 of the leading device 17 are brought into close contact with each other and set integrally, the leading device 17 is moved to the pile installation position. Then, it is installed at a predetermined angle and checked with the inclinometer 17d. Next, the material 4 is supplied from the material supply port 17b.
The leading device 17 is inserted into the ground while pouring, and the support 17c is operated at a predetermined position to maintain the stability and the press-fit angle of the leading device 17.

Next, the bar 2 is operated to press-fit the shoe 2. Subsequent work is to form the slanted pile 1b by the steps shown in FIGS.
7 is removed to complete the work.

As a result, it is possible to easily form a slant pile, which is difficult with the current cast-in-place pile method. In addition, this leading device 17 may be used for the countermeasures for the hole of the straight pile 1a.

FIG. 9 shows an embodiment in which a pile hole is formed in advance and an underground pile is formed in this hole by the method according to the present invention. That is, in the ground where the surface near the ground is hard and the hole wall is self-sustaining even if it is pre-cut and the hole collapse does not occur, it is possible to form an underground pile using this hole, and the construction procedure is, first, As shown in FIG. 9A, the pile hole 8 is separately cut in advance, and the hopper 5 described above is installed on the ground portion of the pile hole 8.

Next, as shown in FIG. 9 (B), the rod (rod) 3 is connected with a hanging tool (temporary holding mechanism) 2g or the like so that the shoe (shoot) 2 does not come off, and is positioned at the construction site. The hopper 5 is set in the opening of the supply section 5b. Then, the material 4 of the underground pile 1 is poured to reach the bottom 18 of the pile hole 8.

Next, as shown in FIG. 9C, the hanging member 2g of the shoe 2 in the above operation is separated at a set depth by means such as cutting. Thereby, after the initial formation of the underground pile 1 is promoted, the rod 3 is actuated to start the press-fitting of the shoe 2 and, when the material 4 is poured while being press-fitted, as shown in FIG. The underground pile 1 can be continuously and simply and efficiently extended. Then, in a state where the press-fitting of the shoe 2 is completed, a predetermined long underground pile 1 can be easily formed by the tamping operation by the reciprocating movement of the rod 3 described above.

According to this method, this method does not completely remove road pavement or hard topsoil (including frozen soil) in which it is difficult for a pile to penetrate unlike conventional methods, and also needs to reinforce a hole. By drilling only the pile holes, there is an advantage that the collapse of the ground can be prevented more effectively.

FIG. 10 shows an example of construction in which the underground pile 1 is formed as described above in order to stabilize the embankment 7c and the arc sliding resistance 19a can be increased. That is, the relative density of the original ground 7 is checked, and the underground pile 1 corresponding to this is continuously provided. At this time, the underground pile 1 is connected to the arc sliding surface 19.
Of the base ground 7 and the resistance 19a against the arc slide of the original ground 7 can be increased. In this case, the underground pile 1 is preferably made of a material 4 having a large shear strength and easy to compact.

FIG. 11 shows that the underground pile 1 is formed as described above in order to eliminate the groundwater in the original ground 7 around the embankment 7d of the road and promote the consolidation. Material 4b
In this example, a drainage facility 4a is provided for facilitating drainage and guided to a drainage channel. That is, the construction of the underground pile 1 predicts the volume of the pile body that the ground can tolerate from the relative density of the original ground 7 and forms the underground pile 1 corresponding to this volume, so that the consolidation settlement of the ground is terminated early. At the same time, since the filling material of the pile makes the soft ground dense at the same time as the above-mentioned pile supporting force, there is an advantage that the ground supporting force can be easily increased. The underground pile 1 may be filled with a material 4 having high permeability and not clogging.

FIG. 12 shows that when a horizontal force 20c acts on the foundation 20b such as the abutment 20a, the underground pile 1 is used as a support pile and the straight pile 1 is used.
2a and the shoe 2 of FIG.
An example of the construction is shown in FIG. The procedure for constructing the inclined pile 1b is based on the operation using the leading device 17 shown in FIG. As a result, the slanted pile 1b can be formed easily and efficiently, so that the slanted pile 1b can be suitable as a countermeasure capable of resisting horizontal force and earth pressure at the time of an earthquake acting on a structure and a building foundation. And other advantages.

FIG. 13 shows that the underground pile 1 is used as a support pile on the foundation 21b of the retaining wall 21a of the site, and the length of the underground pile 1 is freely selected according to the height of the irregular support layer 15. An example is shown in which the work is formed. In this case, the support force management of the underground pile 1 is to check the axial force 6 at the time of press-fitting the rod 3 and obtain a desired support force. The underground pile 1 is used in combination with the above-mentioned filling material 4 and core material 11 according to a desired supporting force. In order to counter the height difference of the support layer, there are many wasteful operations such as the use of an unstable yatco in a conventional pile driving method or the cutting of a pile left behind on the ground and cutting it later. On the other hand, in the case of this construction method, the length can be freely selected according to the height, so that the conventional work can be simplified and the construction period can be shortened, and at the same time, the underground pile can be easily formed with safe and low construction cost. There are advantages such as possible.

FIG. 14 shows an example of construction in which the method and apparatus for forming an underground pile by mechanical construction described above are applied to a method for manually molding. As shown in FIG. 14 (A), a bar (rod) 3 is connected to a shoe (shoot) 2 with a screw or the like, and is installed at a pile position. Next, as shown in FIG. 14 (B), the rod 3 is hit with a hammer or the like 6 and press-fitted, and the pile hole 8 formed at this time is filled with the material 4.

Next, as shown in FIG. 14C, after the rod 3 reaches a predetermined position, the connection between the tip shoe 2 and the rod 3 is released, and the shoe 2 is left in the pile hole 8. Then, the material 4 is compacted by giving an impact 6 while pulling out the rod 3. Then, as shown in FIG. 14 (D), the rod 3 is pulled out from the underground pile 1 and again struck against the pile head in order to compact the material 4 so as to be integrated with the surrounding ground. FIG.
In the case where the shoe 2 and the rod 3 are fixed in (A), the material 4 is separately tamped and the underground pile 1 is left in a state where the rod 3 is left.
May be molded.

[0067]

[0068]

According to the present invention, the following effects can be obtained by the above configuration.

According to the first aspect of the present invention, the material at the same time is filled while the shoe (shoot) provided at the tip is press-fitted with a rod (rod), thereby preventing the collapse of the pile hole and the shoe at the tip of the pile. Since the shape of the underground pile and the direction of press-fitting are maintained and the shoe is left, a stable pile tip supporting force can be reliably obtained.

[0070] This makes it possible to form an underground pile having a desired cross section and length by a simple method, and to efficiently form an underground pile having high precision necessary for strengthening the ground at a low cost. Can be.

According to the second aspect of the present invention, when the material is clogged in the pile hole due to the intermeshing or stickiness of the particles and continuous filling becomes impossible, this device is operated to break the clogged state of the material and facilitate the injection. At the same time, the material is oriented toward the wall surface of the pile hole while breaking the closed state of the material, so that the effect of stabilizing the pile hole wall can be obtained.

According to the third aspect of the present invention, the material for the pile pillar can be freely selected, and when a highly permeable material is used for the underground pile, groundwater can be removed by using the underground pile and the ground can be removed. Consolidation can be promoted and consolidation settlement can be terminated early.

Further, the gap in the original ground is further densified by the above-mentioned compaction action in addition to the filling of the material. This allows
In addition to the ability to increase the bearing capacity of the original ground, effects such as suppression of land subsidence and liquefaction at the time of an earthquake are produced.

The underground pile of this construction method has an advantage that it can be widely applied to the basic design because the existing theoretical analysis can be used.

According to the fourth aspect of the invention, a multi-stage underground pile having a different diameter can be formed, so that the pile supporting force and the bending strength and the horizontal strength of the pile head can be easily increased. .

According to the fifth aspect of the present invention, the shoe left at the tip of the underground pile, the rod for press-fitting the shoe, and the supply device for supplying the material are provided so that the underground pile can be smoothly formed by continuous operation. In addition, there is an advantage that the device is simple and inexpensive by using a bar for press-fitting the shoe also as a tamping tool.

Since the underground pile is accurately and efficiently formed to a desired depth by the above-mentioned apparatus, and at the same time, the material to be filled is formed into a dense and high-quality pile, so that the guide pipe can be used even in a special place such as at sea. If a crane and a crane are used together, the work of forming an underground pile becomes easy.

According to the sixth aspect of the present invention, even when the ground at the pile hole is unstable, the sheath of the leading device can be inserted into the ground to stabilize, and the leading device can maintain the press-fitting angle while pouring the material. Therefore, there is an advantage that the inclined pile, which is difficult with the current cast-in-place pile method, can be easily formed, and that the leading device can be used for countermeasures for a pile hole of a straight pile.

According to the seventh aspect of the present invention, the material can be densely filled in the pile hole, and it is suitable as an apparatus for solving the problem even when the material is closed in the pile hole and continuous filling of the material becomes impossible. It is.

According to the eighth aspect of the present invention, there is an advantage that the compaction force of the soil at the tip of the pile is reduced by the action of the drill by the integral operation of the shoe as the rod is pushed and rotated. Further, by attaching a cylindrical guide to the outer periphery of the shoe and suppressing the runout of the hole when the shoe is press-fitted with the rod, the press-fitting angle can be properly maintained. As a result, underground piles can be widely applied to foundation design, including various soft ground and slant piles, which are difficult with the current cast-in-place pile method.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of an underground pile forming method and apparatus according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a shoe (a shoe) used for a tip portion of a pile used for the above construction.

FIG. 3 is a side view showing an embodiment of an apparatus used when a filling material is closed in a pile hole.

FIG. 4 is an explanatory view of a construction order for forming an underground pile.

FIG. 5 is an explanatory diagram classifying and showing the underground piles of the present invention based on a conventional construction method.

FIG. 6 is a cross-sectional view showing an embodiment in which a pile body of an underground pile according to the present invention is reinforced.

FIG. 7 is an explanatory diagram showing a construction order of pile bodies in a special place such as construction at sea.

FIG. 8 is a cross-sectional view showing a configuration of a leading device required for forming a slant pile.

FIG. 9 is an explanatory diagram of construction means for forming an underground pile in an existing pile hole.

FIG. 10 is an explanatory diagram showing a construction example of preventing a slip failure by using the pile method according to the present invention.

FIG. 11 is a cross-sectional view showing a construction example in which groundwater is removed by using a highly permeable material for an underground pile.

FIG. 12 is a cross-sectional view showing a construction example of a slanted pile suitable for a case where a horizontal force acts on a foundation.

FIG. 13 is a cross-sectional view showing a construction example in which a pile body is formed in accordance with the depth of a support layer.

FIG. 14 is an explanatory diagram showing a construction order of pile bodies by manual construction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Underground pile 2 Shoe (shoot) 3 Rod (rod) 4 Material (filling material) 5 Hopper (material supply device) 6 Pressing force 7 Original ground 8 Pile hole (hole) 9 Pile hole wall (hole wall) 11, 14 Core material 12 Slide tube 15 Support layer 16 Guide tube 17 Lead device

Claims (8)

[Claims] 1. A shoe is pressed into the ground with a rod to form a pillar-shaped pile hole, a material is filled from above the pile hole to prevent the collapse of the pile hole, and the shoe has a predetermined depth. When the shoe reaches the bottom, the bar is reciprocated while the shoe is left at the bottom of the pile, and the material is pulled out while sequentially squeezing the material from below, thereby forming a pile column of the filling material in the ground. Underground pile forming method. 2. The underground pile according to claim 1, wherein a slide tube is connected to a rod for press-fitting the shoe at an arbitrary position on the rod shaft so that the rod can reciprocate. Method. (3) crushed stone, concrete, slag, recycled aggregate,
A pile column is formed by selecting a material such as a drain material, and a design form of a composite ground in which the pile column is integrated with a support pile, a friction pile, an original ground, and a drain pile can be selected. The method of forming an underground pile according to claim 1 or 2, wherein the underground pile is formed. 4. A step of refilling a shoe into the formed pillar with a rod to fill a material from above while forming a pile hole, thereby forming an underground pile having a diameter larger than that of the lower part. 4. The method of forming an underground pile according to claim 1, wherein the steps are repeated to form a multi-stage underground pile having a diameter gradually increasing from below. 5. A stake is provided at the tip of a rod to be press-fitted so as to be separable, and a supply device for supplying material is provided above a stake hole formed by the shoe to form the stake while forming the stake. An underground pile forming device that supplies materials to holes and forms underground piles. 6. A structure in which a pod tube provided with a material supply port prevents collapse of a pile hole opening, a clinometer is fixed to the pod tube, and a support is attached to maintain a press-fitting angle of the pile. The underground pile forming apparatus according to claim 5, further comprising a leading device provided. 7. The underground pile forming apparatus according to claim 5, wherein a slide pipe having a projection or a screw is connected to an arbitrary position on a rod shaft. 8. The underground pile forming apparatus according to claim 5, wherein the projecting portion of the shoe is formed in a conical surface and a guide is attached to the outer periphery of the shoe.