JP3380861B1 - Pile construction method - Google Patents

Abstract

An object of the present invention is to provide a method for constructing a pile that can enhance the bearing capacity of the pile by utilizing the property of the steel making slag generated in the steel making process to expand by absorbing water. SOLUTION: Pile 1 is built in excavation hole H,
The slag 2 which has expansibility in the outer peripheral part and the inside of this pile 1
The slag 2 is expanded and the support force of the pile 1 is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing piles, and in particular, a property of expanding by absorbing water, which converter slag and / or electric furnace slag (herein referred to as "steel making slag") has. The present invention relates to a method of constructing a pile, in which the bearing capacity of the pile is enhanced by using the.

[0002]

2. Description of the Related Art Conventionally, as a method for securing the bearing capacity of a pile, the tip and the peripheral part of the pile are filled with earth and sand, crushed stone, soil cement, etc., and mechanical vibration and compressive force are added as necessary. A method of consolidating the ground around the piles,
A method of forming attachments such as knots, wings, wings, and wedges on a pile has been put into practical use.

[0003]

By the way, among the methods of securing the supporting force of the pile, in the method of consolidating the ground around the pile, the gap between the pile to be built and the pile is generally narrow, There is a problem that it is difficult to fill the filling material uniformly without forming cavities, and it is not easy to efficiently transmit mechanical vibration and compression force to the deep layer portion. There is a problem that liquefaction is likely to occur when an earthquake occurs when a granular material having a good filling property is used as the filler. Further, in the method of forming an accessory on the pile, there is a problem that it is difficult to consolidate below the accessory.

By the way, since steelmaking slag has a property of expanding by absorbing water, its use as a material for civil engineering and construction is currently limited. Specifically, as an example of using this converter slag, as a method for improving soft ground, the converter slag is cast into a column in the soft ground layer, and the water absorption and water permeability of the slag are used as a sand drain pile. In addition to the above-mentioned construction method (see Japanese Patent Laid-Open No. 6-116937), there is only a case where the steelmaking slag is used as a roadbed material by utilizing the solidification characteristics and water permeability.

However, when the steelmaking slag is used as a sand drain pile or a roadbed material, the expansive property of the steelmaking slag causes a problem to the contrary. Therefore, when using the steelmaking slag, 100 hours in steam at about 100 ° C. By applying an aging treatment for maintaining the degree of expansion, the expandability of the steelmaking slag is eliminated. Thus, the use of steelmaking slag is costly in terms of energy consumption, etc., so it is not always effectively utilized,
The current situation is that the development of applications for steelmaking slag that does not undergo aging treatment has been a particular issue.

The present invention utilizes the property of steelmaking slag that expands by absorbing water, in view of the problems relating to the development of the bearing capacity of the pile and the problems relating to the effective utilization of the steelmaking slag, which the above-described conventional pile construction method has. Then, it aims at providing the construction method of the pile which was able to raise the bearing capacity of the pile.

[0007]

In order to achieve the above object, the invention according to claim 1 builds a pile in an excavation hole, and at the same time, the outer peripheral portion and / or the inside of the pile is made of steel having expandability. It is characterized in that the slag is filled and the supporting force of the pile is increased by expanding the slag. In this case, filling the bottom of the pile with slag is not excluded. Here, "steel slag having expandability"
Loses its expansiveness by being aged.
It refers to steelmaking slag that has not been made.

According to the first aspect of the invention, the slag filled in the outer peripheral portion and / or the inside of the pile built in the excavation hole expands by absorbing water. As a result, due to the expansion of the slag that fills the outer periphery of the pile, even if the gap between the pile to be built and the pile is narrow, the filler can be uniformly filled without forming cavities, and the deep layer portion can be filled. Also, the compressive force can be transmitted, and the ground around the pile can be easily and surely consolidated to enhance the bearing capacity of the ground, thereby enhancing the bearing capacity of the pile. Further, due to the expansion of the slag filled inside the pile, the expansion force in the radial direction of the pile exerts a pressing force in the radial direction of the pile, and the rigidity of the pile can be increased, while the axis of the pile is increased. Swelling force in the direction, stress corresponding to the overloaded load on the pile (prestress)
Can be applied, which can increase the bearing capacity of the pile. Further, the steelmaking slag can be effectively used.

The invention according to claim 2 is characterized in that the expansion coefficient of the slag to be filled is adjusted according to the property of the ground for constructing the pile, the purpose of the pile to be constructed, and the like.

According to the second aspect of the invention, the expansion of the slag whose expansion coefficient is adjusted according to the properties of the ground for constructing the pile, for example, the clay layer, the sand layer, the purpose of the pile to be constructed, etc. The ground around the pile can be compacted to the required strength. In addition, the slag that fills the upper position of the pile acts as a lid (in this case, it is desirable to adjust the expansion rate of the slag that fills the upper position of the pile to be small), and the ground around the lower position of the pile is further enhanced. Can be effectively compacted.

According to the third aspect of the present invention, a flange is formed on the outer periphery of the pile at a predetermined interval in the longitudinal direction, and the flange controls the expansion location and direction of the slag filled in the outer periphery of the pile. It is characterized by doing so.

According to the third aspect of the present invention, by controlling the expansion location and the direction of the slag filled in the outer peripheral portion of the pile by the brim formed on the outer periphery of the pile at predetermined intervals in the longitudinal direction, The constructed pile can be provided with an effect like a knot pile, thereby further improving the bearing capacity of the pile.

Further, according to the invention of claim 4, the excavation hole for building the pile is formed to have a large diameter in the upper position and a small diameter in the lower position, so that the slag is filled in a stepped manner with different diameters. It is characterized by doing so.

According to the fourth aspect of the present invention, it is possible to increase the supporting force of the ground at the position of the excavation hole formed to have a large diameter, thereby increasing the supporting force (horizontal proof force) of the pile.

Further, the invention according to claim 5 is characterized in that a plurality of excavation holes for building piles are mutually connected at an upper position so that the slag is filled in a plane shape.

According to the fifth aspect of the present invention, the supporting force of the ground at the positions of the excavated holes interconnected to each other at the upper position can be increased, whereby the supporting force (horizontal bearing capacity) of the pile can be further increased. Further, when the ground is sandy ground, it is possible to more smoothly discharge pore water during an earthquake until the slag solidifies.

The invention according to claim 6 has expandability.
Steelmaking slag is used in addition to being used as a main component, and steelmaking slag after aging treatment, blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud, fly ash, refuse incineration slag , Waste incineration ash, sludge slag, crushed glass, waste gypsum, industrial waste such as waste concrete, gypsum, quick lime, cement, crushed stone,
It is characterized in that the expansive property of steel-making slag having expansiveness, which is a mixture of one or more kinds of building materials such as earth and sand, artificial materials, and minerals, can be utilized.

According to the invention of claim 6, since the aging treatment of the steelmaking slag is not required, the steelmaking slag can be used at a low cost, and the steelmaking slag can be used more effectively.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a pile construction method according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the pile construction method of the present invention. In this embodiment, a steel pipe pile 1 which is predetermined in design is used.
In accordance with the outer diameter and depth of the steel pipe pile 1, the excavation hole H is excavated in the ground, the steel pipe pile 1 is built in the excavation hole H at a predetermined depth, and the outer peripheral portion and the inside of the steel pipe pile 1 are expanded. The slag 2 which it has is filled with a predetermined density.

In this case, the inner diameter of the excavation hole H is set to be slightly larger than the outer diameter of the steel pipe pile 1 so that the required amount of slag 2 can be filled in the outer peripheral portion of the steel pipe pile 1. . In addition, although the steel pipe pile 1 has a straight shape in the present embodiment, a steel pipe pile having ribs or the like on the inner and outer peripheral surfaces is used as necessary so as to be suitable for the ground or a construction to be built. You can Also, if necessary,
The bottom of the steel pipe pile 1 can be filled with slag.

The expansive slag 2 that fills the outer peripheral portion and the inside of the steel pipe pile 1 is a steelmaking slag, preferably a steelmaking slag before aging treatment, or a steelmaking slag as a main component. Steelmaking slag after aging treatment, blast furnace slag, ferroalloy slag, granulated slag, copper smelting slag, red mud (aluminum smelting slag), fly ash, waste incineration slag, waste incineration ash, sludge slag, glass crushed material, waste plaster , Industrial wastes such as concrete scraps, plaster, quicklime, cement, crushed stone, earth and sand, building materials such as clay, artificial materials, minerals that can utilize the expansiveness of steel slag mixed with one or more Can be used.

Since the steelmaking slag before aging treatment has a particularly remarkable property of expanding by absorbing water, it can be suitably used for the method of constructing a pile of the present invention.

In FIG. 2 (A), a steelmaking slag having a grain size of 5 mm under and before aging treatment is used, and JIS A 501 is used.
The results of the expansion test based on No. 5 are shown. Figure 2 (A)
As is clear from the above, the expansion characteristics (expansion rate) of the steelmaking slag before aging treatment differ depending on the environment, temperature, blending, chemical composition and the like.

The water granulated slag has innumerable bubbles,
Since it has an angular shape, it has light weight, large shear resistance, water permeability, and hydraulic property, and can be suitably used for the method for constructing a pile of the present invention. Then, by filling the outer peripheral portion and the inner portion of the steel pipe pile 1 with the slag 2 having such characteristics, when the ground is sand ground, the release of pore water at the time of earthquake until the slag 2 solidifies. It can be carried out smoothly and the ground can be prevented from being liquefied in advance. Moreover, the hydraulic property enhances the bearing capacity of the ground, thereby enhancing the bearing capacity of the pile.

In FIG. 2 (B), a mixture of steelmaking slag and granulated slag is hermetically stored in a plastic bag so that moisture (5% to 8%) does not dissipate, and the curing days are taken out for 28 days and 90 days. The results of measuring the uniaxial compressive strength are shown below. Figure 2 (B)
As is clear from the above, it is understood that as the mixing ratio of the steelmaking slag increases, the uniaxial compressive strength increases due to the solidification phenomenon, which is effective in improving the bearing capacity.

As the slag 2 to be filled into the outer peripheral portion and the inside of the steel pipe pile 1, the same kind of slag is used, and if necessary, the slag having a different expansion coefficient, for example, the outer peripheral portion of the steel pipe pile 1 is filled. As the slag, a slag having a larger expansion coefficient than the slag filled inside can be used.

Then, the slag 2 having such characteristics
By filling the outer peripheral portion and the inside of the steel pipe pile 1,
The slag 2 filled in the outer peripheral portion of the steel pipe pile 1 absorbs water contained in the surrounding ground (expanded if necessary), and expands to build a pile. Even if the gap between the steel pipe pile 1 and the steel pipe pile 1 is narrow, the slag 2 as the filler can be uniformly filled without forming a cavity, and the compressive force can be transmitted to the deep layer portion. The surrounding ground can be easily and surely consolidated to increase the bearing capacity of the ground, thereby increasing the bearing capacity of the steel pipe pile 1, and the expansion of the slag 2 filled in the steel pipe pile 1 By the radial expansion force of the steel pipe pile 1, the pressing force is applied in the radial direction of the steel pipe pile 1, and the rigidity of the steel pipe pile 1 can be increased, while the expansion force of the steel pipe pile 1 in the axial direction is increased. Then, the stress (p Stress) can apply,
As a result, the supporting force of the steel pipe pile 1 can be increased. Further, the uniaxial compressive strength is increased by the solidification phenomenon of the slag 2 filled in the outer peripheral portion of the steel pipe pile 1, and the liquefaction prevention of the ground and the supporting force can be improved.

FIG. 3 shows a second embodiment of the pile construction method of the present invention. In this embodiment, slags having different expansion coefficients and different water absorption performances are appropriately combined and used according to the properties of the ground, so that the ground having a complicated stratum structure can be dealt with. Also in this embodiment, the first
Similar to the embodiment, the excavation hole H is excavated in the ground according to the outer diameter and the depth of the steel pipe pile 1 which are predetermined in design, and the steel pipe pile 1 is built in the excavation hole H at a predetermined depth. The outer peripheral portion of the steel pipe pile 1 is filled with the expansive slag 2 at a predetermined density. In the present embodiment, the steel pipe pile 1 is not filled with slag, but it may be filled with slag as in the first embodiment.

In this case, as the slag filled in the outer peripheral portion of the steel pipe pile 1, for example, as shown in FIG. 2 (A), in the clay layer H1, the slag 2 mixed with quick lime is used.
For the sand layer H2, the slag 2b having a large expansion coefficient before the aging treatment is used. As a result, in the clay layer H1, slag 2 mixed with quick lime 2
a absorbs water and generates heat, and the slag 2a is rapidly hardened, and at the same time, the clay layer H1 can be improved.
Further, in the sand layer H2, the slag 2b having a large expansion coefficient can effectively compact the sand layer H2.

Further, as shown in FIG. 2B, the expansion coefficient of the slag may be changed according to the depth to compact the ground around the steel pipe pile 1. More specifically, for example, the slag 2c having a small expansion coefficient is used at the upper position H3 of the steel pipe pile 1 and the slag 2d having a large expansion coefficient is used at the lower position H4. Thereby, the upper position H3 of the steel pipe pile 1
Since the slag 2c with a small expansion coefficient that has been filled in the first part hardens and acts as a lid, when the slag 2d with a large expansion coefficient that has filled the lower position H4 of the steel pipe pile 1 expands and hardens with a delay, The expansion is restrained and the expansion in the circumferential direction allows the surrounding ground to be more effectively compacted.

FIG. 4 shows a third embodiment of the pile construction method of the present invention. In this embodiment, the flanges 11a and 11b are formed on the outer periphery of the steel pipe pile 1 at predetermined intervals in the longitudinal direction, and the expansion locations of the slag 2 filled in the outer periphery of the steel pipe pile 1 by the flanges 11a and 11b and It is designed to control the direction. Also in this embodiment, similarly to the first embodiment, the excavation hole H is excavated in the ground in accordance with the outer diameter and the depth of the steel pipe pile 1 which are determined in advance, and the steel pipe pile is placed in the excavation hole H. 1 is built to a specified depth and this steel pipe pile 1
The outer peripheral portion is filled with the slag 2 having expandability to a predetermined density.

In this case, the projecting length of the collars 11a, 11b formed on the outer periphery of the steel pipe pile 1 is such that the slag 2 filling the outer peripheral portion of the steel pipe pile 1 is vertically divided by these collars 11a, 11b. However, the number and intervals of the brims to be formed are not limited to those in the present embodiment, and can be arbitrarily set depending on the length of the steel pipe pile 1, the properties of the ground, and the like. can do.

The slag 2 is filled at the same time as the steel pipe pile 1 is built. In this case, the slag 2 is made of paper, synthetic resin, fiber, It can be arranged around the steel pipe pile 1 in a state of being housed in a bag 20 made of metal or the like (preferably made of paper or synthetic resin that is decomposed by water after being cast). here,
As shown in the left half diagram of FIG. 4, the bag 20 has collars 11a, 11
It may be a small bag divided into strips between b or one large bag as shown in the right half of FIG.

As a result, the expansion location and direction of the slag 2 filled in the outer peripheral portion of the steel pipe pile 1 can be controlled by the collars 11a and 11b formed on the outer periphery of the steel pipe pile 1 at a predetermined interval in the longitudinal direction. Completed and constructed steel pipe pile 1
Can have a large frictional force-producing effect like a node pile, and thereby, the supporting force of the steel pipe pile 1 can be further improved.

If necessary, the brim 11x can be formed at the upper end (ground line GL) of the steel pipe pile 1. As a result, when the slag 2 at the upper end of the steel pipe pile 1 expands, the expansion causes the slag 2 to move to the ground line GL.
It is possible to prevent the steel pipe pile 1 from being pushed upward, and to make the expansion of the slag 2 at the upper end portion of the steel pipe pile 1 effectively act as compaction of the ground.

FIG. 5 shows a fourth embodiment of the pile construction method of the present invention. In this embodiment, a drill hole for building the steel pipe pile 1 is
By forming the slag 2 having a large diameter in the upper position H5 and a small diameter in the lower position H6, the slag 2 having expandability is filled in a stepped manner with different diameters.

In this case, the depth of the upper position H5 formed to have a large diameter can be set according to the nature of the ground, etc., and is usually set to a depth of about 5 to 10 m from the ground line GL. .

As a result, the supporting force of the ground at the upper position H5 of the large-diameter drilling hole is increased, whereby
The bearing capacity (horizontal proof strength) of the steel pipe pile 1 can be increased.

FIG. 6 shows a fifth embodiment of the pile construction method of the present invention. In this embodiment, a plurality of excavation holes for constructing the steel pipe pile 1 are connected to each other at an upper position H7 by excavating in a groove shape, and the expansive slag 2 is planarly filled. is there. In this case, in the lower position H8, a plurality of independent drill holes are formed and filled with the expansive slag 2 as in the above embodiment.

In this case, the depth of the upper position H7 for excavating in a groove can be set according to the nature of the ground, etc., and is usually set to a depth of about 5 to 10 m from the ground line GL. .

As a result, the supporting force of the ground at the positions of the excavated holes interconnected to each other at the upper position H7 can be increased, whereby the supporting force (horizontal proof force) of the steel pipe pile 1 can be further increased. If the ground is sand,
Until the slag 2 is solidified, the interstitial water at the time of an earthquake can be discharged more smoothly through the slag 2 filled in the upper position H7.

[0043]

EXAMPLES Next, more concrete examples of piles constructed using slag will be described in comparison with piles constructed using crushed stone. [Example 1-1] A pile was constructed by using a node pile as the pile and filling the outer peripheral portion of the pile with steel slag (100%) before aging treatment having a grain size of 10 mm under. [Example 1-2] A pile was constructed by using a node pile, and filling the outer peripheral portion of the pile with a mixture of 90% of steelmaking slag before aging treatment having a grain size of 10 mm and 10% of gypsum. [Example 1-3] A node pile was used as the pile, and the outer periphery of the pile was filled with a mixture of 70% of steelmaking slag with a grain size of 10 mm under before aging treatment and 30% of granulated slag with a grain size of 2 mm under. The pile was constructed. [Example 1-4] A peg was used as a pile, and the outer peripheral portion of the pile was filled with a mixture of 80% of steelmaking slag with a grain size of 10 mm under before aging treatment and 20% of concrete waste material with a grain size of 5 mm under. Pile was constructed. [Comparative Example 1] A pile was constructed by using a node pile and filling the outer peripheral portion of the pile with crushed stone (100%) having a grain size of 10 mm under.

[Example 2-1] A cylindrical pile was used as the pile, and the outer peripheral portion of the pile was filled with steel slag (100%) before aging treatment having a grain size of 10 mm under, and the pile was constructed. [Example 2-2] A cylindrical pile is used as the pile, and 90% of steelmaking slag with a grain size of 10 mm under before aging treatment and 10% of gypsum are provided on the outer peripheral portion of the pile.
The pile was constructed by filling a mixture of [Example 2-3] A cylindrical pile is used as the pile, and 70% of steelmaking slag before grain aging with a grain size of 10 mm and grain size of 2 mm is used on the outer periphery of the pile.
A pile was constructed by filling a mixture of 30% of under granulated slag. [Example 2-4] A cylindrical pile was used as the pile, and 80% of steelmaking slag before aging treatment with a grain size of 10 mm and a grain size of 5 mm was used on the outer periphery of the pile.
A pile was constructed by filling a mixture of 20% of the under concrete waste material. [Comparative Example 2] Cylindrical piles were used as the piles, and the outer periphery of the piles was filled with crushed stone (100%) having a grain size of 10 mm under, and the piles were constructed.

The relationship between the load and the amount of subsidence when a load is applied to the piles constructed according to the above-mentioned examples and comparative examples is shown in FIGS. 7 and 8. As is clear from FIG. 7 and FIG. 8, the piles constructed using slag (examples) are all compared to the piles constructed using crushed stone (comparative example), and the settlement amount when a load is applied. It was confirmed that the slab is small and can increase the bearing capacity of the pile. Further, this tendency, rather than using the steelmaking slag before aging treatment alone, when using the gypsum, granulated slag, etc., in the steelmaking slag before aging treatment,
It was also confirmed that it appeared more significantly.

Next, it was confirmed by actually conducting an experiment that the bearing capacity of the pile can be improved by utilizing the characteristic that the steelmaking slag absorbs water and expands. The experiment was systematically performed in three stages. As the slag sample, steel slag before aging treatment is the main component, and gypsum,
Granulated slag, waste concrete, etc. were added.

[Experiment 1] Drum Can Experiment A steel pipe with an outer diameter of 150 mm and a closed tip was used as a drum can (φ600
mm, h900 mm), and was filled with slag so that the rooting depth was 450 mm. The curing was performed by exposing it outdoors. It should be noted that the bottom of the drum can was provided with water so that the slag was cured in a relatively dry state, and when expanded, received a strong restraint from the can wall.

[Experiment 2] Large-scale soil tank experiment N 5 using crushed sand in a concrete soil tank with a depth of 5 m
An artificial ground with a value of about 25 was created, and an outer diameter of 400
mm diameter, 3.0m depth holes are drilled at 1m intervals and outer diameter is 1
A 65 mm steel pipe or a knotted steel pipe having the same size as the knot diameter was built, and slag was filled around the pile. Water was put in the soil tank to a height of 500 mm below the surface to cure each pile.

[Experiment 3] The field-scale experimental ground was a soft ground having an N value of 10 or less as a result of a boring survey, and an intermediate layer having an N value of about 25 was present in the lower layer of 12 m.
Steel piles (outer diameter 457 mm) and concrete knot piles (knot diameter 440 mm, shaft diameter 300 mm) were used as the piles, and the pile length was 12 m. Since the pile construction procedure is soft ground with water flowing out, insert a casing while excavating with a screw auger, then insert another casing inside, and place a pile inside this casing. The slag layer was built around the pile by building and pouring an appropriate amount of slag between the outer casing and the inner casing, and vertically moving the inner and outer casings while rotating.

[Experimental Results] The results of comparison of the bearing capacity performance of the foundation piles in Experiments 1, 2 and 3 with reference bearing capacity from the relationship between the applied load and the settlement
They are shown in Table 1, Table 2 and Table 3, respectively.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

As is clear from Table 1, Table 2 and Table 3,
In each case, a large bearing capacity was obtained by using the slag, as compared with the case where the slag was not used. The bearing capacity changed depending on the slag composition, and the bearing capacity increased with the addition of gypsum, granulated slag, and concrete waste. The effect of increasing the bearing capacity is more remarkable in the node piles when comparing the straight piles (steel pipe piles) and the node piles (concrete node piles) having the node diameters of approximately the same diameter.

Although the pile construction method of the present invention has been described above based on the embodiments thereof, the present invention is not limited to the constructions described in the above embodiments, and the constructions described in the respective embodiments are not limited thereto. The configuration can be appropriately changed within a range not departing from the spirit of the invention, such as appropriate combination. Further, in the above-mentioned embodiment, the steel pipe pile is used for the pile, but the material of the pile is not limited to this, and the construction method of the pile of the present invention is concrete pile (concrete pile with knots). ), Composite piles, cast-in-place piles, and other arbitrary piles.

[0056]

According to the first aspect of the present invention, due to the expansion of the slag filled in the outer peripheral portion of the pile, even if the gap between the pile to be built and the pile is narrow, the filling material forms a cavity uniformly. It is possible to fill without compressing and to transmit the compressive force to the deep layer, and to easily and surely consolidate the ground around the pile to enhance the bearing capacity of the ground, thereby increasing the strength of the pile. The support power can be increased. Further, due to the expansion of the slag filled inside the pile, the expansion force in the radial direction of the pile exerts a pressing force in the radial direction of the pile, and the rigidity of the pile can be increased, while the axis of the pile is increased. Swelling force in the direction, stress corresponding to the overloaded load on the pile (prestress)
Can be applied, which can increase the bearing capacity of the pile. Further, since it is costly in terms of energy consumption and the like in the related art, it is possible to effectively utilize the steelmaking slag whose use is limited.

According to the second aspect of the present invention, the expansion of the slag whose expansion coefficient is adjusted according to the properties of the ground for constructing the pile, for example, the clay layer or the sand layer, the purpose of the pile to be constructed, etc. Thereby, the ground around the pile can be compacted to a required strength. In addition, the slag that fills the upper position of the pile acts as a lid (in this case, it is desirable to adjust the expansion rate of the slag that fills the upper position of the pile to be small), and the ground around the lower position of the pile is further enhanced. Can be effectively compacted.

According to the third aspect of the invention, by controlling the expansion location and direction of the slag filled in the outer peripheral portion of the pile by the brim formed on the outer periphery of the pile with a predetermined interval in the longitudinal direction thereof, The constructed pile can be provided with an effect like a knot pile, thereby further improving the bearing capacity of the pile.

According to the fourth aspect of the present invention, it is possible to increase the supporting force of the ground at the position of the excavation hole formed to have a large diameter, thereby increasing the supporting force (horizontal proof force) of the pile.

According to the fifth aspect of the invention, the supporting force of the ground at the positions of the excavated holes interconnected to each other at the upper position can be increased, thereby further increasing the supporting force (horizontal bearing capacity) of the pile. Further, when the ground is sandy ground, it is possible to more smoothly discharge pore water during an earthquake until the slag solidifies.

According to the sixth aspect of the invention, since the aging treatment of the steelmaking slag is not required, the steelmaking slag can be used at a low cost and the steelmaking slag can be used more effectively.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a construction example of a first embodiment of a pile construction method of the present invention.

FIG. 2 (A) is an explanatory view showing expansion characteristics of a steelmaking slag before aging treatment, and FIG. 2 (B) is an explanatory view showing changes in uniaxial compressive strength of a material in which steelmaking slag and granulated slag are mixed. is there.

FIG. 3 is a vertical cross-sectional view showing a construction example of a second embodiment of the pile construction method of the present invention.

FIG. 4 is a vertical cross-sectional view showing a construction example of a third embodiment of the pile construction method of the present invention.

FIG. 5 is a vertical cross-sectional view showing a construction example of a fourth embodiment of the pile construction method of the present invention.

FIG. 6 is a sectional perspective view showing a construction example of a fifth embodiment of the pile construction method of the present invention.

FIG. 7 is a graph showing the relationship between the load and the amount of settlement when a load is applied to the pile.

FIG. 8 is a graph showing the relationship between the load and the amount of settlement when a load is applied to the pile.

[Explanation of symbols]

H drilling hole H1 clay layer H2 sand layer H3 upper position H4 lower position H5 upper position H6 lower position H7 upper position H8 lower position 1 pile (steel pipe pile) 11a, 11b, 11x Tsuba 2 slag 2a Slag mixed with quicklime 2b Slag with a large expansion coefficient 2c Slag with low expansion coefficient 2d Slag with a large expansion rate 20 bags

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadao Yabuuchi 2-10-10 Koraibashi, Chuo-ku, Osaka City, Osaka Prefecture Geotop Co., Ltd. (72) Inventor Masataka Himeda 1-12, Nagamachi, Hirohata-ku, Himeji-shi, Hyogo Address: Hiroko Giken Co., Ltd. (56) Reference JP-A-7-233527 (JP, A) JP-A-10-331149 (JP, A) JP-A-9-195270 (JP, A) Actual development Sho 61 −6531 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) E02D 5/50 E02D 27/14

Claims (6)

(57) [Claims] 1. A pile is built in an excavation hole, and an outer peripheral portion and / or an inside of the pile is filled with expansive steelmaking slag, and the supporting force of the pile is increased by expanding the slag. Pile construction method characterized by 2. The method for constructing a pile according to claim 1, wherein the expansion coefficient of the slag to be filled is adjusted according to the property of the ground for constructing the pile, the purpose of the pile to be constructed, and the like. 3. A sword is formed on the outer periphery of the pile at predetermined intervals in the longitudinal direction thereof, and the slag is used to control the expansion location and direction of the slag filled in the outer periphery of the pile. The method for constructing a pile according to claim 1 or 2. 4. An excavation hole for building a pile is formed to have a large diameter at an upper position and a small diameter at a lower position so that the slag is filled in a stepped manner with different diameters. The method for constructing a pile according to claim 1, 2 or 3. 5. The pile according to claim 1, wherein a plurality of excavation holes for building the pile are connected to each other at an upper position so that the slag is filled in a planar shape. Construction method. 6. A steelmaking slag having expandability as a main component, which is aged steelmaking slag, blast furnace slag, ferroalloy slag, water granulated slag, copper smelting slag,
Red mud, fly ash, garbage incineration slag, garbage incineration ash,
Industrial waste such as sludge slag, crushed glass, waste gypsum, concrete waste, gypsum, quick lime, cement, crushed stone, earth and sand, building materials such as clay, artificial materials, one or more kinds of minerals mixed, The method for constructing a pile according to claim 1, 2, 3, 4 or 5, wherein the expandability of the steelmaking slag having expandability can be utilized.