JPH02200913A - Operation method for cast in place ready made concrete pile with expanded bottom - Google Patents

Abstract

PURPOSE:To improve the support force of a pile tip, by furnishing insertingly the bottomed expansion portion of a pile body into the inside of a dug hole through a bottomless flexible tube and a bottomed flexible tube, and providing concrete at the insides of the expansion portion and the pile body. CONSTITUTION:A tube casting pipe 9 which has a hauled-in, bellowslike flexible tube 2 made up with the arrangement of a bottomed flexible tube at the inside and also, a bottomless flexible tube at the outside, is inserted into a casting pipe 8 inserted into the opening edge portion of a pile hole H. Next, a bottomed expansion portion W is inserted into the bottom portion of the pile hole through the tube 2 as the bellowlike tube 2 is being released, and concrete 12 is provided at the expansion portion W. Next, a pile body 4 is connected to the expansion portion W, and insertion is made into the bottom portion of the pile hole as the tube 2 is being released, and concrete 12 is provided, and also, concrete 5 is filled into the inside of the pile body 4. In addition, the expansion portion W and the pile body 4, likewise, are made to reach the bottom portion of the pile hole, and the head portion of the pile body 4 is struck.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to the improvement of the expanded bottom cast-in-place ready-made concrete pile construction method, which improves the bearing capacity of the tip of the pile, attenuates negative frixigin after construction, and improves the stability of poured concrete. The purpose is to prevent strength loss and to improve the ease and reliability of construction work.

(Prior art) Various methods for driving so-called expanded cast-in-place concrete piles have been developed and put into practical use. The most representative methods are the first, reverse construction method, and the second, earth drill method.

(Problems to be Solved by the Invention) However, in the case of using the above-mentioned conventional construction method, when concrete is poured into a hole, it is adversely affected by a large amount of groundwater. In particular, in the general construction method that uses a stabilizing solution, concrete is poured in the stabilizing solution, so the formation of viscous gel strength walls and pH are significantly adversely affected by the influence of both Ca ions and OH ions.

In addition, salt in the stabilizing solution reduces the strength per unit cross-sectional area of the poured concrete pile, which is uneconomical as it is necessary to increase the diameter of the pile by that amount, and also prevents quality deterioration. do not have.

Furthermore, if there is activity on the outer surface of a cast-in-place pile, there is a risk that the pile tip may collapse due to negative friction when the pile tip is supported by the supporting ground. In addition, in the reverse construction method and the earth drill method, the pile side wall of the excavated pile hole is not completely retained, and when installing reinforcing bars and tremie pipes in the excavated pile hole in the supporting ground, the side wall of the pile hole collapses and earth and sand fall. It accumulates on the supporting ground, significantly reducing the cross section of the pile tip and causing uneven settlement.

Furthermore, in the Benotoé method, when the casing is pulled out or concrete is placed, a phenomenon in which the reinforcing bars rise together occurs, leading to a decrease in the strength of the pile tip in the supporting ground.

(Means for solving the problem) Is the present invention the above-mentioned prior art? Solving the problems in the
We have developed a construction method for cast-in-place pre-cast concrete piles with high strength and high bearing capacity, which are economical and easy to install. When constructing a pit, insert a double flexible tube into the expanded bottom excavated pile hole, with a bottomed flexible tube on the inside and a bottomless flexible tube on the outside, the length of which is longer than the pile length confirmed in advance by measuring. Insert the bottomed expansion part toward the bottom of the excavation well, place concrete in the bottom expansion part, and pour concrete while connecting the antibody to reach the bottom of the bottomed expansion part at the bottom of the expansion pile hole. The head of the antibody is struck and swung, and the bottomed enlarged part is placed inside the flexible tube and separated from the bentonite liquid using a mechanism pre-installed inside the bottomed enlarged part by the tip of the antibody. This is a method of expanding.

(Function) The double flexible tubes, one without a bottom and the other with a bottom, are folded into a bellows shape in advance, and are sequentially folded from the opening of the poling hole toward the bottom of the hole, with the bag-shaped bottom at the beginning. Charge. While pouring concrete into the expanded bottomed part of the expanded bottomed pile inside the flexible tube, connect the antibody and pour concrete alternately so that the antibody that will become the pile body faces the bottom of the hole; Enlarge the tip of the pile in the supporting ground at the bottom of the hole.

(Example) The specific content of the present invention will be explained below based on the example of the drawings.
(F) shows a vertical cross section of the excavated pile hole. In the figure, (A) is a vertical cross-section of a pile hole H drilled by the earth drilling method, which is the most common method of excavation, drilling while supplying a stabilizing liquid. is filled with a stabilizing liquid l, and a top casing 8 is fitted around the opening edge to prevent the upper ground from collapsing.

Figure (B) shows a tube casing pipe 9 in which a flexible tube 2 with a bottom is inserted into the outer circumferential surface in advance in a bellows-like manner, and the bottom surface of the flexible tube 2 is the upper surface of the stabilizing liquid. It shows that there is.

Figure (C) shows a state in which the bottomed enlarged part W is inserted through the flexible tube 2 toward the bottom of the pile hole while unraveling the bellows-shaped flexible tube, and mortar concrete 12 is being poured. At the same time, the pump 10 is shown pumping bentonite liquid I in a volume equivalent to that of the bottomed enlarged portion to the outside of the excavated pile hole H. (C) A- in Figure 2
A shows a state in which the bottomed enlarged portion is filled with mortar concrete N2.

Figure (D) shows that the antibody 4 is connected to the bottomed enlarged part W, and the flexible tube 2 is unraveled and charged to the supporting ground at the bottom of the pile hole H. At the same time, the bentonite liquid 1 with the same volume as the antibody is charged. is pumped out of the excavated pile hole H by the pump IO, and concrete 5 is being poured into the antibody 4. In Figure 2 (D) B-B, the concrete 5 is the pile body 4.
(D)C-C shows the internal structure of the bottomed expanded portion W, which is filled with mortar concrete 12 and shows the state before expansion.

In Figure (E), the tube casing pipe 9 that was connected to the upper end opening of the flexible tube 2 is removed, and the pipe is inserted into the supporting ground by 50 cm from the pre-measured pile length or by the length of the pile diameter at the expanded bottom. After hitting the pile cap, measuring the rebound, and confirming the supporting capacity, the flexible tube 2 and the antibody 4 are trimmed at the planned height. FIG. 2(E) D-D shows the concrete 5 filled inside the pile body 4 and the mortar concrete 12 filled between the flexible tube 2 and the outside of the pile body 4.
shows.

Furthermore, the concrete of the excavated pile hole H in Figure 1 (E)! Pump bentonite liquid 1 pushed up to the ground due to the difference in specific gravity between bentonite liquid 2 and bentonite liquid I! 0, the water is pumped out of the excavated pile hole H.

Figure (F) shows that the reinforcing bars 3 are attached to the head concrete 5 of the antibody 4 and the pile body 4, and the head treatment is performed, and the casing pipe 8 is pulled out to complete the construction of the expanded bottom pile. Figure 2 (F)! "-P shows a cross-sectional view of the connecting locus R of antibody 4.

Figure 3 shows a cross section of the internal structure of the expanded bottom at the tip of the pile.

Figure (A) shows the outside of the bottomed enlarged part W in which the tip of the antibody 4 is filled with concrete 12, and shows the state where the antibody 4 is charged into the bentonite liquid 1 at the bottom H of the excavated pile via the flexible tube 2.

Figure (A) shows the inside of the unexpanded form of the expansion mechanism of the bottomed expansion part W.

Figure (i) shows the initial state in which the bottomed expansion part W is opened by the tip of the antibody 4, and the concrete 12 flows out from the joint of the strip-shaped expansion mechanism and the bottom surface of the bottomed pile hole H in the bottomed flexible tube 2. From concrete! 2 is filled, and the bentonite liquid 1 is beginning to be pushed up to the upper ground of the expanded pile hole H due to the difference in specific gravity.

Figure (a) shows the expander 1 and I of the bottomed expansion part W using the pile body 4.
The image shows a state in which K + is pushed open and the enlargement mechanism ' also begins to open.

Figure (C) shows a state in which the bottomed enlarged part W is opened by the tip of the antibody 4, and shows a state in which the bottom of the bottomed enlarged part W is hit by the pile body 4 and penetrates into the supporting ground, and then the concrete I2 is It shows the state where it is filled and the bentonite liquid is pushed up.

Figure (2) shows a state in which the bottomed enlarged part W has been completely opened by the antibody 4 and expansion has been completed, and both the bottom of the bottomed enlarged part W and the antibody 4 have penetrated into the supporting ground by impact.

Figure (E) shows a state in which the antibody 4 is raised to an arbitrary height while penetrating the bottomed enlarged part W that has penetrated the supporting ground, but it is also possible to raise and lower the pile body 4 at an arbitrary height. This facilitates smooth filling of the concrete I2 between the antibody 4 and the flexible tube 2.

Figure (1) shows a state in which the pile body 4 is pulled up to an arbitrary height while the bottomed enlarged portion W penetrating into the supporting ground remains enlarged.

Figure (E) shows that after the pile body 4 moves up and down, the concrete 12 is filled up to the height of the bottomed enlarged part W and the outer periphery of the pile head of the pile body 4, becoming hardened concrete I4, and the inside of the pile body 4 is filled with hardened concrete. 15, the band R attached to a predetermined position of the pile body 4 indicates that the bottomed enlarged part W is fixed to the supporting ground from above by the impact of the pile body 4, and the bottomed enlarged part W is fixed to the supporting ground from above. The expanded bottom pile is constructed with the pile tip of body 4 closed. Similar results can be obtained even if the upper and lower connecting portions R of the antibody 4 are screwed in, or the antibodies are connected by electric welding or the like. The upper pile is connected to the upper pile by a reinforcing bar 13 attached inside the antibody 4.

Further, in the above embodiment, a steel pipe was used as the antibody 4 in constructing the pile, but the material is not necessarily limited to any material as long as it can be used as an antibody depending on the purpose.

(Effects of the Invention) As described above, the present invention provides an antibody with a bottomed enlarged portion attached to the bottomed flexible tube and a bottomless flexible tube in the bottomed bottomed excavated pile hole toward the bottom of the bottomed bottomed drilled pile hole. When constructing ready-made concrete piles with an expanded bottom, place concrete in the excavated pile hole to avoid enlarging the bottomed expansion part in the supporting ground that has been excavated with a bottom. Because the concrete is placed inside the antibody through a flexible tube, the stabilizing liquid used when polling the excavation hole does not come into direct contact with the poured concrete, so there is no negative effect from the stabilizing liquid. The strength has been significantly improved compared to underwater concrete piles made using other construction methods, and the resistance can be made thinner to account for the improved strength, reducing the amount of concrete used. When double-layered flexible tubes made of highly flexible tubes are used, it is possible to significantly attenuate the negative flexible tube that occurs in the clay of the excavated ground, and by adjusting the length of the flexible tube, a frictional effect can be expected. Therefore, the long-term bearing capacity of the pile can be controlled. Furthermore, after construction, sufficient bearing capacity is ensured as there will be no adverse effects from underground pressurized water, and the expanded bottom section built on the support layer will be expanded mechanically, and the tip of the pile will be connected to the bottom of the bottomed expanded section. Since the blockage allows rebound to confirm the bearing capacity, and the influence of slime at the bottom of the pile is extremely small, the bearing capacity of the pile as designed is ensured even though it is a cast-in-place pile.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the construction method of an expanded-bottomed cast-in-place concrete pile according to an embodiment of the present invention in the order of construction. FIG. 2 is an enlarged sectional view of each section in FIG. 1. FIG. 3 is a sectional view showing the movement of concrete within the bottomed enlarged portion W and the flexible tube in FIG. 1. Expanded bottom excavated pile hole l ~ Stabilizing liquid flexible tube (2i: [i) Reinforcing bar
4 ~ U pipe concrete top casing Vibe tube casing Vibe pump Mortar concrete reinforcing bar (for anti-connection) Hardened mortar concrete 15 ~ Conocrete W - Bottomed enlarged part R ~ Anti-connection part inventor Hiroshi Sato Patent applicant GDF (C) Ltd. A to A Figure 2 (D) CN6 (E) E-E Procedural amendment Nichido type) 1. Display of the case 1999 Patent Application No. 20449 2゜Name of the invention Construction method for expanded-bottom cast-in-place ready-made concrete piles 3゜Relationship with the case

Claims (12)

[Claims] (1) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, direct the expanded bottomed part of the antibody that will become the bottom expanded pile toward the bottom of the excavated pile through the bottomless flexible tube and the bottomed flexible tube in the excavated pile hole. This is a method of constructing ready-made concrete piles with an expanded bottom, in which concrete is poured into the concrete inside the concrete pile. (2) When constructing an expandable pile in an expanded-bottom excavated pile hole, after charging two layers of bottomless flexible tubes and bottomed flexible tubes into the excavated pile hole, the expanded-bottomed pile will be formed inside the bottomed flexible tube. 2. The method for constructing a ready-made concrete pile with an expanded bottom and cast in place according to claim 1, wherein the concrete is poured after the expanded bottomed portion of the antibody and the antibody are charged toward the bottom of the expanded bottom excavation. (3) When constructing an expanded pile in an expanded-bottomed excavated pile hole, two layers of bottomless flexible tube and bottomed flexible tube are stacked in advance in the excavated pile hole, and the bottomed expanded portion of the bottomed expanded pile inside the bottomed flexible tube is 2. The method for constructing a cast-in-place concrete shaft with an expanded bottom according to claim 1, wherein the flexible tube and the antibody are sequentially charged toward the bottom of the excavated pile hole while pouring the concrete into the antibody. (4) When constructing an expanded pile in an expanded-bottomed excavated pile hole, two layers of bottomless flexible tube and bottomed flexible tube are stacked in advance in the excavated pile hole, and the bottomed expanded part and antibody are connected through the bottomed flexible tube. According to claim (1), the concrete is charged toward the bottom of the excavated pile, and after filling the bottomed enlarged part of the pile and the outer periphery of the antibody with highly fluid concrete, the concrete that will become the inside of the antibody is poured. Construction method for expanded-bottom cast-in-place concrete piles. (5) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, after inserting the bottomed enlarged part of the antibody that will become the bottomed pile into the excavated pile via the bottomless flexible tube and the bottomed flexible tube, Concrete is poured into the base expansion part and the antibody, and an expansion mechanism is installed inside the bottomed expansion part to expand the tip of the bottom expansion pile with the antibody, and the expansion mechanism itself spreads in all directions toward the outer periphery of the antibody at the pile tip. A method of constructing an expanded cast-in-place ready-made concrete pile according to claim (1), wherein the pile is made into a structure. (6) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, direct the expanded bottomed part of the antibody that will become the bottom expanded pile to the bottom of the excavated pile through the bottomless flexible tube and the bottomed flexible tube in the excavated pile hole. concrete is placed inside the antibody, and the expanded bottomed part at the tip of the pile is expanded in the bottomed flexible tube by the rocking pressure of the antibody, and the concrete poured inside the antibody is poured into the bottomed expanded part of the excavation. At this point, the joint made in the shape of a strip of the bottomed expansion part opens, and highly fluid concrete is discharged from the expanded joint, and the bentonite liquid is pushed by the difference in specific gravity between the concrete 2.4 and the bentonite liquid 1.1. The bottom-expanding place casting according to claim (1), wherein raised concrete is filled from the bottom of the excavated pile and replenished with concrete into the inside of the antibody head, so that the concrete is filled up to the head of the outer peripheral side of the antibody in the excavated pile hole. Construction method of product concrete pile. (7) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, direct the expanded bottomed part of the antibody that will become the bottom expanded pile to the bottom of the excavated pile through the bottomless flexible tube and the bottomed flexible tube in the excavated pile hole. After charging the concrete previously placed inside the pile and discharging it from the enlarged section and filling the concrete into the excavation hole, the antibody was struck toward the bottom of the pile to obtain rebound in order to confirm the supporting capacity of the pile. The method for constructing an expanded-bottomed, cast-in-place ready-made concrete pile according to claim (1), wherein the slime remaining at the bottom of the pile hole is thickened at the bottom of the bottomed expanded portion by utilizing the force exerted by the force. (8) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, the bottomed enlarged part of the antibody that will become the bottom expanded pile is charged into the excavation hole through the bottomless flexible tube and the bottomed flexible tube toward the bottom of the excavation. While pouring concrete and expanding the expanded bottomed part of the expanded bottomed pile, highly fluid concrete is discharged into the bottomed flexible tube.Due to the difference in specific gravity between the concrete and bentonite liquid, it is poured from the bottom of the pile through the flexible tube. and push it up to the ground,
The method for constructing a cast-in-place concrete pile with an expanded bottom according to claim (1), wherein the concrete and bentonite liquid do not come into direct contact with each other. (9) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, direct the expanded bottomed part of the pile body that will become the expanded bottom pile toward the bottom of the excavated hole through the bottomless flexible tube and the bottomed flexible tube in the excavated hole. Concrete is cast while charging, and the expanded bottomed part is expanded by the impact of the pile body at the bottom of the pile hole, and the bottom of the expanded bottomed part and the support surface of the tip of the pile body are integrated at the bottom of the expanded bottomed excavated pile hole. The method for constructing an expanded cast-in-place ready-made concrete pile according to claim (1), wherein the tip of the pile is closed. (10) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, excavate the expanded bottomed part of the pile body that will become the expanded bottom pile into the pile hole via a bottomless flexible tube and a bottomed flexible tube. Concrete is cast while charging toward the bottom of the pile hole, and after expanding the bottomed expansion part with the pile body at the bottom of the pile hole, the concrete is poured smoothly between the entire bottomed expansion part, the flexible tube on the outer periphery of the pile body, and the pile body. 2. The method for constructing a cast-in-place concrete pile with an expanded bottom according to claim 1, wherein the pile body is moved up and down at an arbitrary height within the enlarged portion of the expanded bottom pile so that the concrete can be filled with concrete. (11) When constructing an expanded bottom pile in an expanded bottom excavated pile hole, excavate the expanded bottomed part of the pile body that will become the expanded bottom pile into the pile hole via a bottomless flexible tube and a bottomed flexible tube. Concrete is placed while charging toward the bottom of the pile hole, and the bottomed expansion part is expanded by the pile body at the bottom of the pile hole of the bottomed flexible tube. Alternatively, by adjusting the flexible tube from two layers to one, you can expect the frictional force around the pile body.In calculating the long-term bearing capacity of the pile, the tip of the expanded bottom pile has the bearing capacity as a driven pile, and the area around the pile body is a friction pile. The method for constructing the expanded-bottom cast-in-place ready-made concrete pile according to claim (1), which can be expected to have a bearing capacity of 1. (12) When constructing an expanded-bottom pile in an expanded-bottom excavated pile hole, after inserting the pile body into the excavated pile hole through a bottomless flexible tube and a bottomed flexible tube toward the bottom of the excavated pile, The expanded bottomed section expands, and the concrete ejected from the expanded bottomed section is filled between the flexible tube and the pile due to the difference in specific gravity between the concrete and bentonite liquid due to the swinging of the pile body, and is deposited in the ground of the excavated pile hole. Claim (1) wherein the flexible tube and concrete protect the outer periphery of the pile body, and the inside of the pile body is filled with concrete to prevent corrosion of the pile body.
) Construction method for cast-in-place concrete piles with expanded bottoms.