JP2022080696A - Pile and its construction method and underground structure - Google Patents

Abstract

To provide a pile, its construction method, and an underground structure that can solve the problem of dealing with existing piles in the case of constructing a new structure on a site with the existing piles, especially the problem of securing additional space in the case of installing new piles while keeping the existing piles in place.SOLUTION: The inventive pile 100 is a pile that is buried underground to support a structure 300 above ground, and has an open tip 120 and a pile body 110 with an inside diameter that encapsulates an existing structure P in the ground at a construction target site. The pile 100 is constructed on the ground so as to encapsulate the existing structure P around the existing structure P in the ground at the construction target site.SELECTED DRAWING: Figure 1

Description

The present invention relates to piles, construction methods thereof, and underground structures.

When removing the existing structure built on the foundation pile and constructing a new structure there, like rebuilding a house, the treatment form of the existing pile is mainly (1) "direct use", (2) "retention". , (3) "Removal". "Direct use" is a form in which existing existing piles are directly used in a new building (see, for example, Patent Document 1), and "retention" is a pile while leaving the existing piles in the ground as a part of the site. "Removal" is a form in which an existing pile is pulled out and a new pile is placed (see, for example, Patent Document 2) (see FIG. 28).

JP-A-2017-122364 Japanese Unexamined Patent Publication No. 2017-66721

However, each of these forms has its own challenges. That is, in the case of "direct use", it is unknown whether a predetermined bearing capacity can be obtained by the existing existing pile. In the case of "retention", it is not always possible to secure a space for constructing a new pile, which is likely to become apparent especially when the site is small. Also, in the case of "removal", the amount of work for foundation work associated with the removal of existing piles is generally two to four times that at the time of new construction, and it is not easy to re-evaluate the site ground after construction. is the current situation. In light of this situation, technological development of ground survey methods and foundation structure design methods according to the form of treatment of existing piles (reuse, retention, removal) has become an urgent issue.

Therefore, the present invention presents a problem in processing existing piles when constructing a new structure on a site having existing piles, and in particular, a problem in securing new space when constructing new piles while preserving existing piles. The purpose is to provide piles, their construction methods, and underground structures that can solve the problem.

One aspect of the present invention is a pile buried in the ground to support a structure on the ground.
With the open tip,
The pile body that contains the existing structure in the ground at the construction site, and
It is a stake with.

This pile can be installed so as to cover the outside of the existing structure such as the existing pile so as to be contained therein. By using the piles constructed in this way, the problem that it is difficult to secure space for new piles will be solved, and new structures will be supported by constructing new piles on the ground where existing piles have been retained. It is possible to secure sufficient bearing capacity.

The pile as described above may further include a blade portion formed on the pile main body portion.

The blade portion of the pile as described above may be provided only on the peripheral surface of the tip portion.

The blade portion of the pile as described above may be continuously and spirally provided on the peripheral surface of the main body portion.

The blade portion of the pile as described above may be provided intermittently on the peripheral surface of the main body portion.

In the pile as described above, an excavation assisting tool that comes into contact with a part of the existing structure may be provided on the inner peripheral side, the tip portion or the peripheral surface of the pile main body portion.

Another aspect of the present invention is an underground structure in which piles such as those described above are buried and constructed in the ground.

Yet another aspect of the present invention is a pile construction method in which a pile having an open tip is constructed on the ground so as to include the structure around the existing structure in the ground at the construction target site. ..

In the pile construction method as described above, the support portion that exerts the bearing capacity of the pile in the ground may be positioned in the soil layer where a predetermined bearing capacity can be obtained in the ground.

In the pile construction method as described above, the pile may be constructed on the ground to a position where the tip portion is deeper than the lower end of the existing structure.

In the pile construction method as described above, a hydraulic material may be supplied to the inside of the pile to integrate the existing structure contained in the pile with the pile.

According to the present invention, there is a problem in processing existing piles when constructing a new structure on a site with existing piles, and in particular, a problem of securing new space when constructing new piles while keeping existing piles. Can be resolved.

It is a figure which shows the outline of the ground where the pile was constructed in the 1st Embodiment of this invention. It is (A) the figure near the tip part and (B) the bottom view which shows the example of the pile in the 2nd Embodiment of this invention. It is (A) the figure near the tip part and (B) the bottom view which shows the other example of the pile in 2nd Embodiment of this invention. It is (A) the figure near the tip part and (B) the bottom view which shows the example of the pile in the 3rd Embodiment of this invention. It is a figure which shows the other example of the pile in the 3rd Embodiment of this invention. It is a figure which shows the other example of the pile in the 3rd Embodiment of this invention. It is a figure which shows the other example of the pile in the 3rd Embodiment of this invention. It is a figure which shows the other example of the pile in the 3rd Embodiment of this invention. It is a figure which shows the outline of the pile (A) the pile buried to the depth that the tip of the pile becomes deeper than the tip of the existing pile, and (B) the pile buried so that the tip of the pile stops at the shallower depth than the tip of the existing pile. .. It is a vertical sectional view which shows an example of the pile in 4th Embodiment of this invention. It is a figure which shows the example of the existing pile constructed by the pre-boring method. It is a figure which shows the state at the time of constructing the pile with the excavation assisting tool around the existing pile constructed by the pre-boring method. It is (A) vertical sectional view and (B) bottom view of the pile which shows the excavation auxiliary tool composed of the excavation ring. It is (A) vertical sectional view and (B) bottom view of the pile which shows the excavation assist tool composed of a wavy tooth. It is (A) vertical sectional view and (B) bottom view of the pile which shows the excavation auxiliary tool which was composed of a spiral inner peripheral protrusion. It is (A) vertical sectional view and (B) bottom view of the pile which shows the excavation auxiliary tool which consisted of a plurality of claws projecting toward a center. FIG. 5 is a vertical cross-sectional view showing an outline of a pile in which a water-curable material is filled therein and integrated with an existing pile, showing an example of a fifth embodiment of the present invention. FIG. 5 is a vertical cross-sectional view showing an outline of a pile in which a water-curable material is supplied near the tip portion and integrated with an existing pile, showing an example of a fifth embodiment of the present invention. In the sixth embodiment of the present invention, it is a figure which shows an example at the time of constructing a pile around the existing pile which has an enlarged part. In the sixth embodiment of the present invention, it is a figure which shows the other example at the time of constructing a pile around the existing pile which has an enlarged part. In the sixth embodiment of the present invention, it is a figure which shows the other example at the time of constructing a pile around the existing pile which has an enlarged part. It is a figure which shows an example at the time of constructing a pile around the existing pile which has an enlarged part in 7th Embodiment of this invention. It is a figure which shows the other example at the time of constructing a pile around the existing pile which has an enlarged part in 7th Embodiment of this invention. In the eighth embodiment of the present invention, it is a figure which shows an example at the time of constructing a pile around the existing pile which is bent in the middle. It is a figure which shows the other example at the time of constructing a pile around the existing pile which is bent in the middle in the 8th Embodiment of this invention. It is a figure which shows the other example at the time of constructing a pile around the existing pile which is bent in the middle in the 8th Embodiment of this invention. It is a figure which shows the other example at the time of constructing a pile around the existing pile which is bent in the middle in the 8th Embodiment of this invention. It is a figure which shows the processing form of the conventional existing pile as a reference in the case of removing the existing structure built on the foundation pile and constructing a new structure there.

Hereinafter, the configuration of the present invention will be described in detail based on an example of the embodiment shown in the drawings (see FIG. 1 and the like).

[First Embodiment]
The pile 100 is buried in the ground and is configured to support the structure 300. The pile 100 of the present embodiment is installed so as to cover the existing pile P in the ground at the construction target site so as to be contained therein (see FIG. 1). The pile 100 has a structure suitable for such installation, specifically, an open end having a pile main body portion 110 sufficient to include the existing pile P as a target and an open tip portion 120. It is a stake.

Since this pile 100 can be installed so as to cover the outside of the existing pile P, the pile is placed on the ground where the existing pile P is retained while solving the problem that it is difficult to secure a space for new construction of the pile. It is newly provided and makes it possible to secure sufficient bearing capacity to support the new structure (see FIG. 1). In a site where the site is small (narrow land), it may be difficult to install new piles in the gaps and four corners of the existing piles P while keeping them in the ground. In particular, in such a situation, the pile 100 of the present embodiment is left without removing the existing pile P, and a new pile is installed by using the narrow space around the existing pile P to increase the bearing capacity. It is possible to make it. In addition, in each figure, in order to show the difference from other parts in an easy-to-understand manner, the existing pile P is expressed darkly or with hatching (it may represent the cross section of the existing pile P). do not have).

[Second Embodiment]
The pile 100 of the present embodiment includes a propulsion force improving unit for improving the propulsion force of the pile 100 into the ground at the time of construction. Specific examples of the propulsion force improving portion include an excavation claw 122 (see FIG. 2) provided on the bottom surface 121 of the tip portion 120 of the 100, or a peripheral surface 130 of the tip portion 120 on the tip side (vertical) of the bottom surface 121. An excavation blade 124 (see FIG. 3) provided so as to project downward). These excavation claws 122 and excavation blades 124 scrape a part of the ground to improve the propulsive force when a propulsive force is applied to the pile 100 by impact or when the pile 100 itself is rotated.

[Third Embodiment]
The pile 100 of the present embodiment may further include a blade portion 140 formed on the pile main body portion 110. The blade portion 40 can function as a support portion that exerts a support force of the pile 100 in the ground, and depending on its form (for example, if it is formed in a spiral shape), the pile 100 is rotated. It can also function as a member (propulsion force improvement unit) that improves the propulsion force of the time. A specific example of the blade portion 140 will be described.

An example of the blade portion 140 is composed of a spiral blade provided only on the peripheral surface 130 near the tip portion 120 of the pile 100 (see FIG. 4). An excavation claw 142 projecting in the rotation direction (circumferential direction) may be provided on the end surface 141 of the spiral blade portion 140 in the rotation direction. The spiral blade portion 140 may be formed so as to be continuous with the bottom surface 121 (see FIG. 5), or may be formed at a position slightly distant from the bottom surface so as to form a space between the spiral blade portion 140 and the bottom surface 121. It may be (see FIG. 6). Alternatively, the blade portion 140 may be formed continuously and spirally on the peripheral surface 130 of the pile body portion 110 (see FIG. 8), or is formed by a plurality of discontinuous blades formed intermittently. It may be (see FIG. 7). The intermittently formed discontinuous blades may have the same seam position, or may be alternate or disjointed. The diameter of the blade portion 140 does not have to be constant. Although not particularly shown, the blade portion 140 may be formed of a plurality of blades having different diameters, or may be formed so as to include blades having different diameters gradually or stepwise. In addition, the blade 140 does not have to be spiral.

The various blade portions 140 as described above can function as support portions that exert the bearing capacity of the pile 100 in the ground. Further, when constructing the pile 100, the depth of the pile 100 may be appropriately set or changed based on the mode of the blade portions 140. For example, when there is an existing pile P constructed so that at least the tip portion reaches the hard support layer B, the blade portion 140 is a pile 100 composed of a single blade, and the tip portion 120 is the tip of the existing pile P. It can be buried to a depth deeper than that, and the blade portion 140 can be installed so as to enter the support layer B and obtain sufficient support force (see FIG. 9A). Alternatively, a pile 100 having a blade portion 140 composed of a plurality of blades is embedded so that the tip portion 120 stops at a depth shallower than the tip of the existing pile P, and the blade portion 140 is above the support layer B. It may be constructed so as to be in the soft layer A of (see FIG. 9B). Even if the blade portion 140 does not reach the support layer B, it is possible to obtain a predetermined supporting force from the soft layer A via the plurality of blades. When the pile 100 is stopped on the support layer B, in addition to the soft layer A described here, there is a hard intermediate support layer (not shown in particular) (in other words, the soft layer A). If there is a non-soft part in it), it may stop there.

[Fourth Embodiment]
The pile 100 of the present embodiment has a structure particularly suitable for construction around a pile (existing pile P) constructed mainly by the pre-boring method (see FIG. 10 and the like). Here, the pre-boring method is a method in which an excavation hole is provided in the ground in advance and a ready-made pile is built in the hole. In such a pre-polling method, a rooting liquid (such as cement milk) may be injected into the drilling hole, and then a pile circumference fixing liquid may be injected before the pile is built. A portion where the root compaction liquid is solidified (root compaction portion P1) is formed near the bottom of the existing pile P, and a portion where the pile circumference fixing liquid is solidified (pile circumference fixing portion P2) is formed in the other portions. There is (see FIG. 11). These pile circumference fixing portions P2 and rooting portions P1 may interfere with the construction of the pile 100, but in the present embodiment, as the newly installed pile 100, an existing structure is provided on the inner peripheral side of the pile body portion 110. (In the present embodiment, a pile provided with the excavation assist tool 150 that abuts on a part of the pile circumference fixing portion P2 or a part of the root compaction portion P1) is applied (see FIG. 10). When constructing the pile 100, the excavation assist tool 150 reduces the frictional resistance on the inner surface of the pile by scraping off a part of the pile peripheral fixing portion P2, making it easier to bury (see FIG. 12). The shape and structure of the excavation aid 150 are not particularly limited as long as it can function in this way. Specific examples include a circular excavation ring (see FIG. 13) and a wedge-shaped inner circumference. An excavation ring consisting of a continuous ring with wavy blades (see FIG. 14), a spirally formed inner peripheral protrusion (see FIG. 15), and a plurality of intermittent claws protruding toward the center (FIG. 16). The excavation aid 150 can be configured by (see) or the like. Further, like these excavation assist tools 150, the excavation assist tool 150 is formed on the inner peripheral side of the pile 100, and although not particularly shown, the excavation assist tool 150 is formed by a claw or the like provided at the tip portion 120 of the pile 100. You can also do it. Alternatively, although not particularly shown here, the excavation assisting tool 150 may be configured on the peripheral surface 130 of the pile main body 110. Among the many existing piles P, there is a possibility that the pile circumference fixing portion P2 overhangs outward beyond the expectations of the installers, and in such a case, the peripheral surface of the pile main body portion 110 According to the excavation assist tool 150 configured in 130, the pile circumference fixing portion P2 and the like may be efficiently excavated.

[Fifth Embodiment]
In this embodiment, a construction method is adopted in which the strength of the newly constructed pile 100 is improved by integrating the existing pile P and the newly constructed pile 100. As an example of specific means for integrating, the hydraulic material Q is supplied from the base end of the pile 100 during construction, and the inside of the pile 100 (in other words, between the pile 100 and the existing pile P). (Preferably the entire space) is filled (see FIG. 17). Alternatively, the hydraulic material Q is supplied from the base end of the pile 100, and the existing pile P and the inside of the pile 100 (in other words, the space between the pile 100 and the existing pile P) around the tip portion 120. It can also be integrated with the pile 100 (see FIG. 18). As the hydraulic material, cement milk, grout, concrete and the like can be used.

[Sixth Embodiment]
In the present embodiment, a part of the existing pile P has a larger diameter than the other such as a blade portion and an expanded bottom portion, or a portion protruding outward from the others (hereinafter referred to as “enlarged portion”, which is indicated by the reference numeral Pf in the figure. ) Will be adopted, and the pile 100 or construction method will be adopted, which makes it possible or easy to construct. This is particularly useful when targeting existing piles P such as steel pipe piles with blades and piles created at the bottom expansion site. Hereinafter, a specific example will be described (see FIGS. 19 to 21).

As the pile 100, in the present embodiment, a pile whose inner diameter is larger than the enlarged portion Pf of the existing pile P to be targeted and which can contain at least the enlarged portion Pf is adopted. Such a pile 100 may have a uniform outer diameter, inner diameter, and cross-sectional shape (see FIG. 19), and the diameter of such a pile 100 is expanded to a size that can include the enlarged portion Pf only in the portion including the tip portion 120. It may have a shaped shape (see FIG. 20). Alternatively, a construction method may be adopted in which the pile 100 having an inner diameter smaller than that of the enlarged portion Pf of the existing pile P is buried to a depth before it interferes with the enlarged portion Pf (see FIG. 21). By adopting various piles 100 or construction methods such as these, it is possible to avoid problems in construction due to the pile 100 interfering with the existing pile P.

[7th Embodiment]
Contrary to the sixth embodiment described above, the pile head of the existing pile P has a portion having a larger diameter than the others, such as a blade portion and a bottom expansion portion, or a portion protruding outward from the others (enlarged portion Pf). In this case, the following pile 100 or construction method can be adopted to enable or facilitate pile construction. That is, as the pile 100, a pile whose inner diameter is larger than the enlarged portion Pf of the existing pile P to be targeted and which can contain at least the enlarged portion Pf is adopted. Such a pile 100 may have a uniform outer diameter, inner diameter, and cross-sectional shape (see FIG. 22), or may have an outer diameter, inner diameter, and cross-sectional shape that change in the middle (not shown). ). Alternatively, a construction method may be adopted in which only the enlarged portion Pf of the existing pile P is removed first, and then the pile 10 is constructed around the remaining portion of the existing pile P (see FIG. 23).

[Eighth Embodiment]
It suffices if the existing structure such as the existing pile P is in a straight state, but this is not always the case. (See Fig. 24, etc.). In the present embodiment, the following pile 100 or construction method is adopted in order to enable or facilitate the pile construction even when the pile 100 is constructed around the existing structure such as the existing pile P. A specific example will be given (see FIGS. 24 to 27).

As the pile 100, a pile 100 having an inner diameter that can include a part or all of the existing pile P that is bent in the middle is adopted, and the pile 100 is constructed as an inclined pile along the inclination / bending of the existing pile P. (See FIG. 24). Alternatively, an auxiliary destructive jig 152 such as an excavation auxiliary claw is provided at the tip 120 of the pile 100, and the existing pile P is constructed while destroying the portion of the existing pile P that protrudes radially outward from the pile 100. It may be good (see FIG. 25). Alternatively, an auxiliary guiding jig 154 such as a roller may be provided near the tip 120 of the pile 100, and the pile 100 may be guided so as to follow the curve of the existing pile P. See FIG. 26). Alternatively, a bellows is provided in the middle of the pile 100 (for example, around the middle portion in the longitudinal direction) to form a joint portion 156 that sufficiently transmits axial force and bends flexibly, and the pile is formed along the curve of the existing pile P. It may be constructed while bending so that the 100 follows (see FIG. 27).

Although the above-described embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in each of the above-described embodiments, an example of constructing a pile 100 buried in the ground to support a structure has been mainly described, but the pile referred to here literally supports the weight of a structure such as above ground as a simple pile. Needless to say, the present invention can be applied to various other piles or pile-shaped reinforcements in addition to the above. Further, the constructed pile 100 may be a part of an underground structure constructed in the ground.

Further, in each of the above-described embodiments, the case where the pile 100 is constructed around the existing pile P has been described, but the existing pile P is only an example of the existing structure in the ground at the construction target site. In addition to existing piles, it is natural to apply the present invention when constructing piles 100 around existing structures such as direct foundations, columnar improved bodies, etc., in other words, objects that may be obstacles in the ground. Is possible.

The present invention is suitable for application to piles, construction methods thereof, and underground structures.

100 ... Open end pile (pile)
110 ... Pile body 120 ... Tip 121 ... Bottom 122 ... Excavation claw 124 ... Excavation blade 130 ... Peripheral surface 140 ... Blade (support)
141 ... End face in the direction of rotation of the blade 142 ... Excavation claw 150 ... Excavation assisting tool 152 ... Excavation assisting claw (auxiliary destruction jig)
154 ... Induction jig 156 ... Joint part 300 ... Structure A ... Soft layer B ... Support layer P ... Existing pile (existing structure)
P1 ... Root consolidation part P2 ... Pile circumference fixing part Pf ... Enlarged part of existing pile

Claims (11)

A pile that is buried in the ground and supports structures on the ground.
With the open tip,
The pile body that contains the existing structure in the ground at the construction site, and
Stakes with. The pile according to claim 1, further comprising a blade portion formed on the pile main body portion. The pile according to claim 2, wherein the blade portion is provided only on the peripheral surface of the tip portion. The pile according to claim 2, wherein the blade portion is continuously and spirally provided on the peripheral surface of the main body portion. The pile according to claim 2, wherein the blade portion is intermittently provided on the peripheral surface of the main body portion. The invention according to any one of claims 1 to 5, wherein an excavation assisting tool that abuts a part of the existing structure is provided on the inner peripheral side, the tip end portion, or the peripheral surface of the pile main body portion. Pile. An underground structure formed in the ground by burying the pile according to any one of claims 1 to 6. It ’s a pile construction method.
A pile construction method in which a pile with an open tip is constructed on the ground so as to include the existing structure around the existing structure in the ground at the construction target site. The method for constructing a pile according to claim 8, wherein a support portion that exerts a supporting force of the pile in the ground is located in a soil layer in which a predetermined supporting force can be obtained in the ground. The method for constructing a pile according to claim 8 or 9, wherein the pile is constructed on the ground to a position where the tip portion is deeper than the lower end of the existing structure. The pile construction method according to any one of claims 8 to 10, wherein a hydraulic material is supplied to the inside of the pile, and the existing structure contained in the pile is integrated with the pile.

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