KR102494160B1 - Foldable extention pile and construction method of pile driving after drilling thereby - Google Patents

Abstract

Disclosed are a foldable lower-end extension pile and a construction method of boring and driving a pile using the same. The foldable lower-end extension pile according to the present invention has a foldable lower-end extension part arranged on a lower end of a pile. The foldable lower-end extension part comprises: a hinge knuckle disk formed in the shape of a circular steel plate with a diameter identical to the diameter of a pile to be able to be combined with a reinforcement plate on a lower end of the pile, having an inner-side hinge knuckle arranged on each side of an inverted triangle having the three sides thereof maintaining a constant interval from the center, and having an outer-side hinge knuckle arranged on each side of a regular triangle having the three sides thereof expanded more outward from the center than the three sides of the inverted triangle; a moving hinge rotating plate formed in the shape of an arc-shaped steel plate hinged by a hinge pin to each inner-side hinge knuckle of the inverted triangle sides arranged on the hinge knuckle disk in a first hinge part composed of a plurality of hinge knuckles arranged in a row; and a moved hinge rotating plate formed in the shape of an arc-shaped steel plate hinged by a hinge pin to each outer-side hinge knuckle of the regular triangle sides arranged on the hinge knuckle disk in a second hinge part composed of a plurality of hinge knuckles arranged in a row, thereby filling a space between the moving hinge rotating plate and the moved hinge rotating plate. Therefore, provided are a foldable lower-end extension pile and a construction method of boring and driving a pile using the same, wherein the bearing capacity of the fore-end of a pile can be doubled or more without expanding a borehole.

Description

Foldable bottom expansion pile and pile drilling pile construction method using it {FOLDABLE EXTENTION PILE AND CONSTRUCTION METHOD OF PILE DRIVING AFTER DRILLING THEREBY}

The present invention relates to a bottom expansion pile and a pile drilling pile construction method using the same, and more particularly, to PHC piles (Prestressed High-Strength Concrete piles), concrete piles, steel pipe piles, H-beam piles, etc. (hereinafter simply referred to as PHC piles). ) When the foundation construction pile is constructed by a pre-excavation method such as the SDA (Separated Donut Auger) method, it relates to a folding bottom expansion pile that can secure strong bearing capacity at the bottom of the pile and a pile drilling pile driving construction method using it.

Conventionally, in driving a PHC pile (Prestressed High-Strength Concrete pile) for foundation reinforcement during foundation construction of a building, a pile perforation driving construction method (also referred to as a pre-excavation driving construction method) is used. The pile drilling driving construction method first drills the ground to form an excavation hole, fills the grouting, and then inserts a PHC pile into the excavation hole and hammers it. PHC piles are fixed in the ground as the grouting hardens.

As shown in Figure 1, in drilling an excavation hole, SDA (Separated Donut Auger) method is mainly used. The SDA method uses a single auger 102 that rotates a screw rod 106 in a pile driver 100 and a casing auger that rotates a casing 110 in the opposite direction to the screw rod 106. auger) is used simultaneously to drill holes. A drill bit 108 is coupled to the front end of the screw rod 106, and the single auger 102 is connected to the boom support type (crane) or 3-point support type (driver only) of the pile driver 100 to drill while lifting becomes (1,2). The ground continues from the top to the landfill layer, soil layer, weathered soil, weathered rock, soft rock layer, etc., and drilling holes are generally made up to the soft rock layer. However, the depth of the drilling hole may vary depending on the supporting layer according to the design of the foundation.

After accurately matching the tip of the casing 110 and the drill bit 108 to the construction position so that the pile is installed exactly in place according to the design drawing, etc., check whether it is vertical, rotate the upper single auger 102 forward, and Reverse rotation of the casing auger 104 starts drilling. Excavate to the design depth while checking the supporting layer. At this time, it is common for the design depth to penetrate at least twice the diameter of the pile into the support layer. When the design depth is reached, the single auger 102 is pulled out first. At this time, grouting or cement paste is injected as needed. When the drilling is completed, the casing 110 is separated from the casing auger 104 and remains in the drilling hole, and while the single auger 102 is raised and the screw rod 106 is pulled out from the drilling hole, the screw rod 106 ) and drill bit 108 along the inner hollow passage to inject grouting (cement paste) into the drilling hole to be half filled (3,4). In FIG. 1, (5) is an enlarged view of (4).

As shown in FIG. 2, the construction of the PHC pile 114 penetrates the PHC pile 114 by its own weight inside the excavation hole (6, 7), and the PHC pile 114 penetrates the excavation hole. The screw rod 106 and the casing auger 104 are lowered to the top of the casing 110 to connect the casing auger 110 and the casing 110, and then the casing auger 104 is raised to pull out the casing 110. (6,7,8,9), and proceeds in the order of driving the penetrating PHC pile with a drop hammer (120) (10). Pulling out the case (110) and driving by the drop hammer (120) can change the order. The pile 114 is detected in two orthogonal directions to coincide with the center of the excavation hole, erected vertically, and then gradually inserted by the weight of the pile. Finish the final penetration with a low vibration and low noise method up to the design penetration depth. Afterwards, to set up the piles, the piles are installed at the work place by installing a transheet and a plumbing weight to carry out the construction after vertical inspection in 2 directions, and the location of the mezzanine on the pile is 12m or less, the point 2m from the end line of the head of the pile, 13m or more The file is placed at 1/2 of the length of the file. After the file installation is completed, the file that rises for some reason is retyped and penetrates to the original depth. The final penetration amount is precisely measured using a self-supporting measuring stand, and the average value of 10 hits is set to 5 mm or less for the calculation of the final penetration amount. (11) of FIG. 2 is an enlarged view of the PHC pile driven by penetration. After completion of penetration driving, safety accidents are prevented by backfilling the area around the PHC pile with floating soil and sand using a forklift.

The commonly used pile penetration driving construction method has the advantage of a short pile penetration construction time and reduced noise, but has a weak bearing capacity, so many methods for reinforcing the bearing capacity have been proposed.

3 to 7 show a method of reinforcing bearing capacity by an extended edition PHC pile in which an extension plate having a larger diameter than the pile diameter is attached to the bottom of the pile.

As shown in FIGS. 3 and 4, the expansion plate PHC pile is a disk with a diameter (550 mm in the example of the drawing) that is about 10% larger than the diameter of the pile (500 mm in the example of the drawing) on the reinforcing plate 118 at the bottom of the PHC pile. Attached, it strengthens the bearing capacity. In this way, when a disc with a larger diameter than the pile diameter is attached to the bottom of the pile, the bearing capacity increases, but the size of the drill hole for penetrating the pile increases by about 30% or more than the diameter of the pile, so the following problems arise. there is.

As shown in Figures 5 and 6, in the case of drilling by the SDA method, in the case of drilling by the SDA method, the diameter of the drilling hole is 30% or more than the diameter of the pile in order to allow the expansion plate to be easily inserted. (In the example of the drawing, it must be drilled with a size of 650 mm or more).

As shown in FIG. 7, the driving construction method after perforation of the expansion plate PHC pile is the process of injecting the expansion plate PHC pile 114 after grouting, injecting it by penetration driving, and drawing out the casing 110. It is the same as the pile-up construction method after drilling piles. However, in this process, in order to construct an extended version PHC pile, the excavation hole has to be larger than that of the existing PHC pile, causing various problems. This will be described in detail with reference to FIGS. 3 to 7 .

As shown in FIGS. 3 to 6, in order to construct the expansion plate PHC pile by the driving construction method after pre-excavation, the diameter of the excavation hole should be 30% or more larger than the diameter of the PHC pile. This is because the diameter of the bottom of the pile increases due to the expansion plate. To this end, the diameter (outer diameter) of the casing is 558 mm (approximately 111.6% of the pile diameter) for the existing PHC pile diameter of 500 mm, whereas the extended version PHC pile has a casing diameter (outer diameter) of 609 mm (about 111.6% of the pile diameter) for a pile diameter of 500 mm. about 121.8%). This is an indispensable choice for penetrating the extended version PHC pile into the casing. On the other hand, if the diameter of the casing is increased in this way, the diameter of the drilling hole increases to 650 mm or more (about 130% or more of the pile diameter) when the casing is removed. This means that the diameter of the excavation hole is larger than the diameter of the pile by more than 130%, and it means that a large air gap occurs between the pile and the inner wall of the excavation hole.

Due to the geologic structure of Korea, there is a lot of groundwater and the geology is unbalanced, so the soft layer, sand layer, and groundwater layer are unpredictably distributed in the ground.

As shown in FIG. 7, in order for the normal foundation pile construction to be performed, the construction in the same state as (6) should be performed, but if a soft layer, a sand layer, or a soil layer with a lot of groundwater exists in the ground, if the expansion plate PHC pile construction is performed, the excavation hole Since the diameter of the pile is excessively larger than the diameter of the pile, a large gap (void) occurs between the pile and the inner wall of the excavation hole, and when the casing is removed after pile construction, the adjacent ground collapses into the gap between the pile and the excavation hole, causing ground subsidence around the pile. occurs (see (4), (5) in Fig. 7), the pile is excessively tilted to one side and it is difficult to maintain verticality (see (4), (5) in Fig. 7), collapsed soil, etc. It mixes with the grouting around the pile and interferes with the normal curing of the grouting. In this case, the bearing capacity of the extended version PHC pile is weaker than that of the above-described existing PHC pile, so that it cannot function properly as a foundation pile. In particular, there are many soil layers mixed with soft layers, sand layers, and groundwater in the ground in Korea, so these problems frequently occur during the construction of expanded PHC piles at actual domestic apartment sites, requiring additional construction costs for re-construction or reinforcement construction. Cases are occurring at various construction sites.

In addition, when it is necessary to pull out the installed file due to a file installation position error, a file depth error, etc. after constructing the extension plate, it is difficult to pull out the file because the extension plate maintains the expanded state even when the file is pulled out. Therefore, once the extension piles are constructed, re-construction is very difficult.

On the other hand, it is common for conventional PHC piles or expanded PHC piles to be constructed by drilling to the support layer of the bedrock (soft rock layer) of the position to be constructed during construction (see Figs. 1 and 7). If the bottom of the excavation hole is not flat and solid like the weathered rock layer, it is difficult to maintain the pile vertically and it is difficult to secure a large bearing capacity. However, due to the characteristics of the region in Korea, there are many places where the geology up to the bedrock is quite deep. Therefore, when performing foundation construction with existing PHC piles or expanded PHC piles, drilling holes must be drilled deeply.

However, the existing PHC pile or expanded PHC pile construction method, which needs to be deepened to the soft rock layer, has many limitations in performing foundation construction on small acreage lands scattered among buildings in the city center or at reconstruction and redevelopment construction sites. In the case of using the existing PHC pile or expanded PHC pile construction method for building construction on a site with a small land area, the depth of the foundation pile is large, so large drilling driving equipment must be input, but if the place to be constructed is narrow, large drilling pile driver It is difficult to assemble and install, so many cases give up construction. When foundation pile construction is performed by a large drilling pile driver between buildings, the floating soil from the excavation hole picks up the auger screw and falls onto surrounding buildings and roads from a high point, causing a great danger. Even if a dust net is installed to prevent this, it is difficult to secure safety when the drilling pile driver is installed high. In addition, when a large perforation pile driver is installed between buildings in the city center, ground subsidence is likely to occur at the installation point, which can cause damage to nearby buildings or human life if the pile driver overturns. Subsidence or sinkhole phenomenon may further occur, resulting in a major safety accident. In addition, when constructing deep-depth foundation piles in a narrow place, a lot of money is invested for safety measures, and the construction period not only takes a considerable amount of time, but even if construction is performed, safety after construction is not guaranteed.

Therefore, there is a need for a foundation pile capable of securing sufficient bearing capacity even at a low depth, such as weathered soil or weathered rock, and a pre-excavation pile construction method using the same.

The invention of Korean Patent Registration No. 10-0672039 relates to a reinforced pipe part formed to a certain depth to be assembled at one end of a pile, and the pile strength against the soil stress of the bottom and hole wall of a pile hole attached to the bottom of the reinforced pipe part and excavated. In the head expansion type pile comprising a reinforcing plate having an area of a certain diameter larger than the pile diameter, it is assembled on the bottom surface of the reinforcing plate and gradually slides when hit and expands to be embedded in the hole wall of the pile hole to maintain the tip bearing capacity Disclosed is a variable extension member of a head extension type file having a configured variable extension means. Korean Patent Registration No. 10-0672039 invention is a sliding variable expansion means, a variable expansion support plate assembled in a certain shape to slide and spread in all directions on the bottom of the reinforcing plate, and a variable expansion support plate assembled at the center of the variable expansion support plate, which is pushed outward when twisted. It is described to me that it can be made of a configuration including an extension push part assembled in the center and projecting a certain length downward.

However, in the invention of Korean Registered Patent No. 10-0672039, when the extension push part is in contact with a flat surface such as a soft rock layer and is accurately designed, the variable extension support plate can be pushed and slid when hit, but the extension push part is seated like weathered soil or weathered rock. In a place where it is difficult to do, there is a disadvantage that it is difficult to push the variable extension support plate even if it is puttted. Therefore, the invention of Korean Registered Patent No. 10-0672039 also has a problem in that the excavation depth must be deepened to the soft rock layer, like the conventional PHC pile or extended PHC pile construction method. In addition, as can be seen in the drawing, the variable expansion member of the head expansion type pile according to Korean Patent Registration No. 10-0672039 has a diameter of the casing and a drilling hole because the diameter of the reinforcing pipe and the reinforcing plate is larger than the diameter of the pile. It has the same problem as the extended PHC file described above in terms of size.

6 of the invention of Korean Registered Patent No. 10-0672039 is another embodiment of a variable extension member applied to a head-extending pile, which extends to a diameter larger than the diameter of the pile when extended to the bottom of the reinforcing plate at a certain angle toward the outside from the center. Disclosed is a variable extension plate in which only the central side is attached to a fixing attachment part to be spread out and expanded by weight or a twist at the edge. It is explained that the variable extension plate is formed to overlap each other while being cut to a certain size and spreads when the pile is weighed or hit, and functions as a reinforcing plate. Therefore, the variable extension plate cannot be folded or unfolded when weight or hard hitting is not applied to the variable extension plate. However, as shown in FIG. 6 of Korean Registered Patent No. 10-0672039, when the center side of the variable extension plate is attached to the center of the reinforcing plate by the fixing attachment, the variable extension plate is unfolded by its own weight or a pinch hit, making it difficult to install the pile. Even after completion, there is a problem that the pile rises to the top again by the restoration of the fixing attachment over time. When the weight of the fixed attachment portion is greater than the plasticity of the fixed attachment portion, it is difficult to maintain the supporting force by the variable extension plate because the fixed attachment portion is cut off.

Registered Patent Publication Registration No. 10-0672039 (registration date: 2007.01.15)

The present invention was made to solve the above-mentioned problems of the conventional foundation pile, and the first problem to be solved by the present invention is a folding bottom expansion pile that can increase the pile end support capacity by more than twice without expanding the excavation hole and a pile using the same It is to provide a perforation driving construction method.

A second problem to be solved by the present invention is to provide a folding bottom expansion pile capable of securing sufficient bearing capacity even at a low depth such as weathered soil or weathered rock, and a pile drilling pile driving construction method using the same.

A third problem to be solved by the present invention is to provide a folding bottom expansion pile that can continue to be unfolded once it is unfolded and embedded in the bottom wall of an excavation hole, and a pile drilling driving construction method using the same.

The above-described objects of the present invention, in a pile for drilling an excavation hole in advance by an auger and inserting it into the excavation hole to reinforce the ground, providing a foldable lower extension at the lower end of the pile, the foldable lower extension, Inner hinge knuckles are provided on each side of an inverted triangle formed in the shape of a circular steel plate with the same diameter as the pile diameter so that it can be coupled to the reinforcing plate at the bottom of the pile, and the three sides maintain a certain distance from the center, and the three sides from the center of the inverted triangle. A hinge knuckle disc having an outer hinge knuckle on each side of an equilateral triangle extending outward more than three sides, and a first hinge portion consisting of a plurality of hinge knuckles arranged in a row. To each inner hinge knuckle of an inverted triangle side provided on the hinge knuckle disc In the second hinge portion composed of a main hinge pivoting plate formed in the shape of a fan-shaped steel plate hinged by a hinge pin and a plurality of hinge knuckles arranged in a row, each outer hinge knuckle of the side of an equilateral triangle provided on the hinge knuckle disc by a hinge pin It can be solved by including a driven hinge pivoting plate formed in a fan-shaped steel plate shape that is hinged and can fill the space between the main hinge pivoting plates.

The main hinge-rotating plate forms a first equal-width extension portion extending in parallel from both ends of the first hinge portion, a first fan-shaped extension portion extending in an oblique direction from the first equal-width extension portion, and an outer boundary of the first fan-shaped extension portion. and a first arc portion having a radius of curvature greater than the radius of curvature of the excavation hole.

The driven hinge pivoting plate extends in an oblique direction from both ends of the second hinge part and unfolds horizontally in the second fan-shaped extension and the second fan-shaped extension in contact with the first equal width extension of the main hinge pivoting plate. When it extends in parallel and spreads out horizontally, it forms the outer boundary of the second equal width extension and the second equal width extension in contact with the first fan-shaped extension of the main hinge rotating plate and has the same curvature radius as the first circular arc. In the unfolded state, the outer boundary forms a larger disk than the excavation hole together with the main hinge pivot plate.

According to the present invention, three driven hinge pivoting plates coupled to the inner hinge knuckle of the hinge knuckle disc and three driven hinge pivoting plates coupled to the outer hinge knuckle of the hinge knuckle disc can be folded or unfolded horizontally. Therefore, before penetrating, it is possible to fold the three inner driven hinge pivoting plates and the three outer driven hinge pivoting plates to be accommodated within the pile diameter. Therefore, pile construction can be performed while drilling with the same drilling hole diameter using the same casing as the existing PHC pile. In addition, when the main hinge pivoting plate is slightly inclined outwardly, when the lower end of the pile reaches the lower end of the excavation hole, the main hinge pivoting plate is expanded while pushing the driven hinge pivoting plate due to its own weight or a blow. At this time, the expanded width can be increased by more than twice as much as possible by extending the length of the main hinge pivoting plate and the driven hinge pivoting plate. Therefore, according to the present invention, unlike the expansion plate PHC pile or the existing head expansion type pile, there is no need to enlarge the diameter of the casing or the diameter of the drilling hole, and the ground subsidence around the pile, which can occur by expanding the drilling hole, While preventing weeping, loss of verticality, and poor grouting curing, it is possible to easily double or more the holding capacity of the tip of the pile.

The foldable lower extension part according to the present invention can be unfolded even if the bottom of the excavation hole is not flat. Therefore, there is no need to flatten the bottom of the excavation hole by drilling the excavation hole to the soft rock layer, and the foundation pile can be constructed in a state in which the weathered soil or weathered rock layer is drilled. Therefore, it is possible to construct foundation piles at a lower depth than existing PHC piles or extended version PHC piles. As described above, since the expansion area and bearing capacity of the foldable lower extension part according to the present invention can be easily increased, sufficient bearing capacity can be secured even when weathered soil or weathered rock layers are drilled. Therefore, when constructing a small building on a narrow site between buildings in the city center, since the depth of the pile is low, the construction cost is low, the construction material is secured smoothly, and it is possible to provide a very useful foundation pile that can shorten the construction period. can

In addition, according to the present invention, when it is necessary to pull out a pile installed due to a pile installation position error, a pile depth error, etc. after pile construction, when the pile is pulled out, the main hinge pivot plate and the driven hinge pivot plate are folded to within the pile diameter. By being gathered again, there is an advantage that it is easy to draw out the pile.

1 is a construction diagram showing a construction method of simultaneously proceeding with casing insertion and drilling hole drilling for pile installation using a conventional SDA (Separated Donut Auger) method.
Figure 2 is a construction diagram showing a method of penetrating the PHC pile into the excavation hole drilled by the construction method of Figure 1.
3 is a front view of the lower end of an extension PHC pile that has been used in conventional pre-excavation pile construction.
4 is a bottom view of the extended version PHC file shown in FIG. 3;
5 is a cross-sectional view showing a method of penetrating the expansion plate PHC pile shown in FIG. 3 into the casing.
6 is a cross-sectional view showing a state in which the casing is pulled out after the expansion plate PHC pile is seated on the bottom of the excavation hole.
7 is a construction diagram showing a pre-excavation pile construction method using the extended PHC pile shown in FIG.
8 is a bottom view of the hinge knuckle disc of the foldable lower extension part according to the present invention.
9 is a side view of the main hinge pivoting plate of the foldable lower extension part according to the present invention.
10 is a side view of the driven hinge pivoting plate of the foldable lower extension part according to the present invention.
11 is a bottom view showing a folded state in which the main hinge pivoting plate and the driven hinge pivoting plate of the foldable lower extension part according to the present invention are accommodated within the diameter of a pile or hinge knuckle disc.
FIG. 12 is a perspective view of the foldable lower extension portion shown in FIG. 11 viewed from the bottom.
13 is a perspective view showing the main hinge pivoting plate and the driven hinge pivoting plate of the foldable bottom extension shown in FIG. 11 as viewed from the bottom in a state in which they are spread out of the diameter of the pile or hinge knuckle disc.
14 is a bottom view showing the main hinge pivoting plate and the driven hinge pivoting plate of the foldable bottom extension according to the present invention in a completely unfolded state until they are horizontal.
FIG. 15 is a perspective view of the foldable lower extension part shown in FIG. 14 as seen from the bottom.
16 is a bottom view of a foldable bottom extension shown in a folded state by hingedly combining a main hinge turning plate and a driven hinge turning plate that can be extended to a diameter of 708 mm with a hinge knuckle disc having a diameter of 500 mm so that it can be used for a 500 mm diameter file.
FIG. 17 is a bottom view showing the main hinge pivoting plate and the driven hinge pivoting plate of the foldable lower end extension shown in FIG. 16 in an unfolded state.
18 is a view in the direction of looking directly at the front of the driven hinge pivoting plate in a state in which the main hinge pivoting plate and the driven hinge pivoting plate of the folding lower extension pile attached to the reinforcing plate at the bottom of the pile are folded and the folding lower extension part shown in FIG. It is a front view.
19 is a view in the direction of looking directly at the front of the main hinge pivoting plate in a state in which the main hinge pivoting plate and the driven hinge pivoting plate of the folding lower extension pile attached to the reinforcing plate at the bottom of the pile are folded and the lower folding extension shown in FIG. It is a front view.
20 is a front view showing a state in which the main hinge pivoting plate and the driven hinge pivoting plate of the folding lower extension pile attached to the reinforcing plate at the bottom of the pile as shown in FIG. 16 are horizontally unfolded.
21 to 23 are construction views showing only the main parts of a method of constructing the folding bottom expansion pile shown in FIGS. 18 to 20 in an excavation hole having a diameter of 590 mm.
24 is a construction view sequentially showing a pile construction method using a folding bottom expansion pile shown in FIGS. 18 to 20.

Hereinafter, with reference to the accompanying drawings, a detailed description will be given of a specific embodiment of a folding bottom expansion pile and a pile perforation driving construction method using the same according to the present invention.

First, as can be seen with reference to FIGS. 21 to 23, the folding bottom expansion pile according to the present invention is used as a pile to reinforce the ground by drilling an excavation hole in advance by an auger and inserting it into the excavation hole. The foldable lower expansion pile according to the present invention is provided with a foldable lower extension at the lower end and when it reaches the bottom of the drilling hole, it is expanded in the horizontal direction by its own weight or light hitting and is embedded in the lower sidewall of the drilling hole. Therefore, the downward holding force and the lateral holding force of the foldable bottom expansion pile according to the present invention are greatly improved.

As shown in FIGS. 8 to 10, the foldable lower extension part 1 includes a hinge knuckle disc 3 coupled to the reinforcing plate 118 at the bottom of the pile 114, and the hinge knuckle disc 3 It includes a main hinge pivoting plate 19 hinged to and a driven hinge pivoting plate 31 hinged to the hinge knuckle disc 3 from the outside of the main hinge pivoting plate 19.

As shown in FIG. 8, the hinge knuckle disc 3 is formed in the shape of a circular steel plate having the same diameter as the pile diameter, and the inner hinge knuckle ( 7) is provided, and outer hinge knuckles 13 are provided on each side of the equilateral triangle 11, the three sides of which extend outward more than the three sides of the inverted triangle 5 from the center. Since one row of inner hinge knuckles 7 are formed on all sides of the inverted triangle 5, a total of three rows of inner hinge knuckles 7 are formed. In addition, since one row of outer hinge knuckles 13 are formed on all sides of the equilateral triangle 11, a total of three rows of outer hinge knuckles 13 are formed. In addition, all of the outer hinge knuckles 13 are formed in the direction of the vertices of the inner hinge knuckles 7. Also, all the outer hinge knuckles 13 are disposed outside of all the inner hinge knuckles 7 . Hinge pin holes 15 are formed in the hinge knuckles 7 and 13 to allow hinge pins to be coupled. A bolt hole 17 for bolting to the reinforcing plate 118 of the pile 114 is formed outside the outer hinge knuckle 13 of the hinge knuckle disc 3.

The present invention can be applied to all files having a diameter of 300 mm to 1,000 mm, and at this time, the diameter of the hinge knuckle disc 3 is also formed to be the same diameter as the diameter of the pile.

As shown in FIG. 9, the main hinge rotation plate 19 has a first hinge part 21 consisting of a plurality of hinge knuckles arranged in a row at the top of each of the sides of the inverted triangle provided on the hinge knuckle disc 3. It is formed in the shape of a fan-shaped steel plate hinged to the inner hinge knuckle 7 by the hinge pin 22.

The main hinge pivoting plate 19 includes a first equal width extension portion 25 extending in parallel from both ends of the first hinge portion 21 and a first equal width extension portion 25 extending in an oblique direction from the first equal width extension portion 25. It may be formed of a first circular arc portion 29 that forms an outer boundary between the fan-shaped extension portion 27 and the first fan-shaped extension portion 27 and has a larger radius of curvature than the radius of curvature of the excavation hole.

As shown in FIG. 10, the driven hinge rotation plate 31 has a second hinge part 33 composed of a plurality of hinge knuckles arranged in a row at the top of each outer side of the side of the equilateral triangle provided on the hinge knuckle disc 3 It is hinged to the hinge knuckle 13 by the hinge pin 22 and is formed in a fan-shaped steel plate shape that can fill the space between the main hinge rotating plate 19.

The driven hinge pivoting plate 31 extends in an oblique direction from both ends of the second hinge part 33 and contacts the first equal width extension part 25 of the main hinge pivoting plate 19 when it is spread horizontally. The second fan-shaped extension 37 extends in parallel from the second fan-shaped extension 37 and the second equal width in contact with the first fan-shaped extension 27 of the main hinge pivoting plate 19 when unfolded horizontally. It consists of a second circular arc portion 41 that forms an outer boundary between the extension portion 39 and the second equal width extension portion 29 and has the same radius of curvature as the first circular arc portion 29, and has an outer boundary in an unfolded state. Together with the main hinge rotating plate 19, a disk larger than the excavation hole is formed.

When the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 are configured as above, the diameter of the disc formed when they are unfolded is the first registration extension 25 and the driven hinge pivoting plate 19 It can be adjusted by increasing or decreasing the length of the second fan-shaped extension of the hinge rotating plate 31 at the same rate. That is, in the case of ground requiring a large bearing capacity, the lengths of the first registration extension 25 of the main hinge-turning plate 19 and the second fan-shaped extension of the driven hinge-turning plate 31 are increased at the same rate to form them. It is possible to increase the diameter of the disc to be made.

In addition, when the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 are configured as above, the length from the top of the inner main hinge pivoting plate 19 to the bottom is the upper end of the driven hinge pivoting plate 31. is always greater than the length from to the bottom. Therefore, when the pile descends, the main hinge pivot plate 19 first closes to the bottom of the drilling hole.

According to the present invention, three main hinge pivoting plates 19 coupled to the inner hinge knuckle of the hinge knuckle disc and three driven hinges coupled to the outer hinge knuckle of the hinge knuckle disc The hinge rotation plate 31 can be folded or unfolded horizontally.

11 and 12, before inserting the pile into the casing 110, the main hinge pivot plate 19 and the driven hinge pivot plate 31 are folded so that they are all accommodated within the diameter of the pile. At this time, the lower end of the main hinge rotating plate 19 is inclined by rotating slightly outward than the upper end. If the lower end of the main hinge pivoting plate 19 is not spread outward than the upper end, the main hinge pivoting plate 19 does not hinge even when the weight of the pile or a light hit is applied from the bottom of the excavation hole.

As shown in FIG. 13, when the main hinge pivoting plate 19 is opened by the pile's own weight or beating, the driven hinge pivoting plate 31 is pushed and the driven hinge pivoting plate 31 is also opened.

As shown in FIGS. 14 and 15, when the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 are fully unfolded and in the horizontal direction, the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 forms a disk larger than the pile diameter. As described above, if the lengths of the first registration extension 25 of the main hinge pivoting plate 19 and the second fan-shaped extension of the driven hinge pivoting plate 31 are increased at the same rate, the diameter of the disc can be easily expanded. can That is, according to the present invention, it is possible to easily vary the bearing capacity of the lower extension part of the pile without increasing the size of the excavation hole.

Referring to FIGS. 16 to 23, the present invention will be described in more specific embodiments as follows. Although the present invention can be applied to all piles with a diameter of 300 mm to 1,000 mm, hereinafter, for convenience of description, a pile with a diameter of 500 mm will be exemplified and described.

16 shows a bottom view of a hinge knuckle disc manufactured with a diameter of 500 mm to be used as a foldable bottom extension of a pile with a diameter of 500 mm. As shown in FIG. 17, in this embodiment, the lengths of the first registration extension 25 of the main hinge-turning plate 19 and the second fan-shaped extension of the driven hinge-turning plate 31 extend them completely in the horizontal direction. It was adjusted to be a disk with a diameter of 708 mm when unfolded.

As shown in FIGS. 18 and 19 , the foldable lower expansion unit may be assembled to the reinforcing plate 118 at the bottom of the 500 mm diameter pile 114 by means of bolts. At this time, the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 are folded and accommodated within the diameter of the pile. As shown in FIG. 19, when the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 are unfolded, a disc having a diameter of 708 mm is formed at the bottom of the pile.

As shown in FIG. 21, when the insertion of the casing 11 is finished with the drilling of the drilling hole, the file is penetrated into the casing 11. According to the present invention, since the size of the disc formed by the main hinge-rotating copper plate 19 and the driven hinge-rotating copper plate 31 can be adjusted as large as possible, when the bearing capacity can be secured without drilling to the soft rock layer, weathered soil or It can only drill up to the weathered rock layer. The diameter of the excavation hole is the same as that of the existing PHC pile.

As shown in FIG. 22, when the folding bottom expansion pile descends, the first part in contact with the bottom of the drilling hole is the lower end of the tilted main hinge pivot plate 19 folded. When self-weight or light hitting continues to be applied to the folding bottom expansion pile, the main hinge pivoting plate 19 opens first and pushes the driven hinge pivoting plate 31 to unfold. The main hinge rotating plate 19 is easily unfolded even when the floor is not flat. Therefore, according to the present invention, there is no need to form a flat-bottom excavation hole by drilling to the soft rock layer.

As shown in FIG. 23, when the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 are fully unfolded, a part of their tip is driven into the side wall at the bottom of the drilling hole. If the size of the disc formed by the main hinge pivoting plate 19 and the driven hinge pivoting plate 31 is increased, the part embedded in the side wall at the bottom of the excavation hole becomes wider and deeper.

Referring to FIG. 24, the driving construction method after drilling the pile using the foldable lower extension file according to the present invention will be described as follows. For convenience of description, a case in which a PHC file is used as a file will be described as an example.

As can be seen with reference to FIG. 24, the folding bottom expansion PHC pile according to the present invention can also be constructed by the pre-excavation method by the SDA method and then by the pounding method.

The driving construction method after perforation of the folding bottom expansion PHC pile includes the steps of drilling an excavation hole with the indentation of the casing by the SDA method before penetrating the folding bottom expansion PHC pile, and after injecting grouting, the folding bottom expansion PHC pile into the casing Penetrating into the inside, driving the foldable lower extension PHC pile with a drop hammer so that the foldable lower extension expands horizontally and is embedded in the lower side wall of the excavation hole, and pulling out the casing.

24, the diameter of the PHC pile is 500 mm, the diameter of the screw bit is 525 mm, the outer diameter of the casing is 558 mm (the inner diameter is 534 mm), and the diameter of the through hole drilled through it is 590 mm (the diameter of the through hole at the actual site is may be in the range of 560 mm to 590 mm), and the case in which the width is 708 mm when the foldable bottom extension is unfolded is shown as an example. In this case, the ground contact area of the pile with a diameter of 500 mm is 0.785 m2, whereas the bottom contact area of the foldable bottom extension with a diameter of 708 mm is 1.574 m2. Therefore, it is possible to secure more than twice the intelligence compared to the existing PHC file.

The present invention can be applied when constructing all foundation piles such as PHC piles (Prestressed High-Strength Concrete piles), concrete piles, steel pipe piles, H-beam piles, etc. by pre-excavation method, and when applying the folding bottom extension to them, the foundation piles It is possible to easily obtain at least 200% or more of the tip bearing capacity of the aperture. When applied to steel pipe piles and H-beam piles, the folding bottom extension can be joined by welding.

The folding bottom extension (1) not only increases the floor contact area, but also allows the bottom extension to be deeply embedded and fixed at the bottom of the side wall of the excavation hole, so more bearing capacity can be obtained compared to the existing extension PHC pile, and the folding bottom extension is the PHC Since the pile is supported in a vertical state, there is no tilting of the pile and the verticality can be maintained.

When the folding lower extension part 1 according to the present invention is applied to the tip of the foundation pile for construction, high bearing capacity can be obtained without expanding the diameter of the casing or drilling hole as in the case of the construction of the expansion plate PHC pile. That is, when applying the folding bottom extension according to the present invention, the diameters of the casing and the drilling hole are the same as in the existing PHC pile. For example, if the diameter of the PHC pile is 500 mm, a casing with an outer diameter of 558 mm can be used. When drilling by this standard casing, the diameter of the excavation hole becomes 560mm ~ 590mm as in the construction of the existing PHC pile. Unlike existing expansion piles, the excavation hole is not large, and it forms an excavation hole of the same diameter as a general PHC pile, so stability can be secured during foundation pile construction. In addition, when constructing by applying the folding lower expansion part 1 to the tip of the foundation pile, absolute safety can be ensured because the verticality of the foundation pile can be obtained automatically if only the verticality of the excavation hole is secured.

When constructing existing PHC piles or expanded PHC piles, it is common to drill through the bedrock (soft rock) support layer at the location to be constructed. If the bottom of the excavation hole is not flat and solid, it is difficult to maintain the pile vertically and it is difficult to secure a large bearing capacity. However, due to the characteristics of the region in Korea, there are many places where the geology up to the bedrock is quite deep. In the case of foundation construction with existing PHC piles or expanded PHC piles, drilling holes must be drilled deeply because soft rock layers are drilled.

However, according to the folding bottom expansion file according to the present invention, drilling to the bedrock (soft rock) layer is unnecessary. A soil pressure with an N value of 45:10 (10 cm penetration when a 63.5 kg hammer is dropped 75 cm and hit 45 times) according to a standard penetration test is sufficient. At this time, it is necessary to confirm the accurate bearing capacity by performing a pile dynamic load test, which is a test method for determining the bearing capacity of a pile by analyzing and measuring the stress and speed generated in the pile body during driving. Unlike conventional PHC piles or expanded PHC piles, deep or wide excavation holes are unnecessary, and the pile length can be reduced, so a relatively small drilling pile driver can be used, and the construction cost is low due to the low pile depth, and construction materials can be secured smoothly. It can reduce the cost by shortening the construction period.

The fact that such a low-depth foundation construction is possible provides a useful advantage for foundation construction, especially in small open spaces or reconstruction and redevelopment construction sites scattered between existing downtown buildings. In the case of using the existing PHC pile or expanded PHC pile construction method for building construction on a site with a small land area, the depth of the foundation pile is large, so large drilling driving equipment must be input, but if the place to be constructed is narrow, large drilling pile driver It is difficult to assemble and install, so many cases give up construction. When foundation pile construction is performed by a large drilling pile driver between buildings, the floating soil from the excavation hole picks up the auger screw and falls onto surrounding buildings and roads from a high point, causing a great danger. Even if a dust net is installed to prevent this, it is difficult to secure safety when the drilling pile driver is installed high. In addition, when a large perforation pile driver is installed between buildings in the city center, ground subsidence is likely to occur at the installation point, which can cause damage to nearby buildings or human life if the pile driver overturns. Subsidence or sinkhole phenomenon may further occur, resulting in a major safety accident. In addition, when constructing deep-depth foundation piles in a narrow place, a lot of money is invested for safety measures, and the construction period not only takes a considerable amount of time, but even if construction is performed, safety after construction is not guaranteed. However, according to the present invention, since a relatively small pile driver can be used and the diameter of an excavation hole can be reduced, safe foundation pile construction can be performed.

1: folding bottom extension
3: hinge knuckle disc
5 : Inverted Triangle
7: inner hinge knuckle
9: hinge pin ball
11 : equilateral triangle
13: outer hinge knuckle
15: hinge pin ball
17: bolt hole
19: main hinge rotating plate
21: first hinge part
22: hinge pin
23: hinge pin ball
25: first equal width extension
27: first fan-shaped extension
29: first arc part
31: driven hinge rotating plate
33: second hinge part
35: hinge pin ball
37: second fan-shaped extension
39: second equal width extension
41: second arc part

Claims (4)

In a pile in which a drilling hole is drilled in advance by an auger and inserted into the drilling hole to reinforce the ground, a folding bottom extension is provided at the lower end of the pile,
The foldable lower extension part,
It is formed in the shape of a circular steel plate with the same diameter as the pile diameter so that it can be coupled to the reinforcing plate at the bottom of the pile, and an inner hinge knuckle is provided on each side of an inverted triangle in which three sides maintain a certain distance from the center, and the three sides from the center are in the opposite direction. A hinge knuckle disc having an outer hinge knuckle provided on each side of an equilateral triangle that extends outward more than the three sides of the triangle;
A main hinge rotating copper plate formed in a fan-shaped steel plate shape hinged to each inner hinge knuckle of an inverted triangular side provided on the hinge knuckle disc in a first hinge portion composed of a plurality of hinge knuckles arranged in a row by a hinge pin; and
In the second hinge part composed of a plurality of hinge knuckles arranged in a row, each outer hinge knuckle of the side of the equilateral triangle provided on the hinge knuckle disc is hinged by a hinge pin to fill the space between the main hinge turning plates. Fan-shaped steel plate shape A folding bottom expansion file comprising a; driven hinge pivoting plate formed of.
According to claim 1,
The main hinge-rotating plate forms a first equal-width extension portion extending in parallel from both ends of the first hinge portion, a first fan-shaped extension portion extending in an oblique direction from the first equal-width extension portion, and an outer boundary of the first fan-shaped extension portion. And a folding bottom expansion file, characterized in that consisting of a first arc portion having a radius of curvature greater than the radius of curvature of the excavation hole.
According to claim 1,
The driven hinge pivoting plate extends in an oblique direction from both ends of the second hinge part and unfolds horizontally in the second fan-shaped extension and the second fan-shaped extension in contact with the first equal width extension of the main hinge pivoting plate. When it extends in parallel and spreads out horizontally, it forms the outer boundary of the second equal width extension and the second equal width extension in contact with the first fan-shaped extension of the main hinge rotating plate and has the same curvature radius as the first circular arc. Foldable bottom expansion file, characterized in that the outer boundary in the unfolded state consisting of a second arc portion forms a disk larger than the excavation hole together with the main hinge pivot plate.
A pile drilling pile driving construction method using the folding bottom expansion pile according to any one of claims 1 to 3.

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