JP3935474B2 - Tip preload cast-in-place pile method and pile tip preload device - Google Patents

Description

  The present invention suppresses settlement of cast-in-place concrete piles by applying a load (hereinafter referred to as “preload”) to the ground at the bottom of the pile hole of cast-in-place concrete pile (hereinafter referred to as “pile tip ground”) in advance. The present invention relates to a tip preload cast-in-place pile method and a pile tip preload device used in this method.

  Cast-in-place concrete piles form a pile with a concrete structure in the ground by drilling a hole in the ground from the ground, placing a reinforcing member such as a reinforcing bar in the hole and placing concrete. is there. For this reason, the diameter and length of a pile can be enlarged compared with the driving pile which drives the pile manufactured in the factory into the ground, and it was advantageous in the case of the foundation etc. which require a big bearing force.

  However, cast-in-place concrete piles cause subsidence when a load is applied from above the piles after the concrete is cast and the piles are formed for the following reasons.

  (A) Although the ground in the ground is consolidated by a load such as soil stacked on the upper side, when the pile hole is drilled, the ground stress at the bottom of the pile is released, so that the ground is loosened.

  (B) When a pile hole is drilled through a gravel layer that has been submerged by groundwater, groundwater eruption (boiling) occurs, and the part where the gravel particles flow out loosens unevenly.

  (C) Pile hole drilling is performed while filling the pile hole with water mixed with particles such as bentonite to prevent the hole wall from collapsing, but the bottom of the pile hole at the tip of the pile is ground. A soft heterogeneous portion (slime portion) in which the fine soil particles drilled are precipitated is formed.

  (D) The ground itself in which the pile hole is drilled is heterogeneous depending on the location, and the ground strength varies.

  If the pile sinks, it will have adverse effects such as excessive force acting on the structure provided on the upper part of the pile. Conventionally, the tip support force of cast-in-place concrete piles is evaluated smaller than the tip support force of driven piles by design. Was.

  Moreover, as a method for suppressing the settlement of cast-in-place concrete piles, “tip pile method” has been proposed, but it is very expensive.

  For this reason, as a method of enhancing the bearing capacity of the pile tip ground at the bottom of the pile easily and at low cost, the applicant places concrete on the top with the injection bag body arranged at the pile tip, and after hardening the concrete A method of injecting injection material into the injection bag body and inflating the injection bag body downward from the pile tip to give a preload to the pile tip ground and pre-compress the pile tip ground to suppress subsequent pile settlement. (Hereinafter referred to as “tip preload cast-in-place pile method”) has been proposed (see Patent Document 1).

  However, the above-mentioned tip preload cast-in-place pile method has the following points to be improved.

That is, when injecting the injection material into the injection bag body, the lower end of the injection hose extending from the injection pump substantially below the lead is a surface of the injection bag body that expands in a substantially horizontal direction before the injection starts. The injection material is simply connected to the injection port at the end, and the injection material flows in from a substantially vertical direction substantially perpendicular to the injection bag body having a substantially horizontal plane. Moreover, in the tip preload cast-in-place pile method, the injection bag body is installed in close contact with the gap between the pile tip ground and the pile concrete lower end. For this reason, it is in the same state as when the lower part of the injection port in the injection bag body is closed, and the phenomenon that the injection material does not enter the inside of the injection bag body and only the injection pressure acts has occurred. Along with this, problems such as “clogging” of the injection material occurred near the injection port, and the sheet of the injection bag body was torn due to stress concentration.
JP 2001-214438 A

  The present invention has been made to solve the above-mentioned problems, and the problem to be solved by the present invention is to provide a tip preload cast-in-place that can flow the injection material in a substantially horizontal direction in the vicinity of the injection port of the injection bag body. It is providing the pile construction method and the pile tip preload apparatus used for the construction method.

In order to solve the above problems, the tip preload cast-in-place pile method according to the present invention is:
Pile hole drilling process for drilling pile holes for cast-in-place concrete piles in the ground;
Next, a reinforcing bar basket and an injection bag body attached to the lower end of the reinforcing bar basket are set in the pile hole, and the injection bag body is installed so as to face the pile tip ground at the bottom of the pile hole.・ Infusion bag body setting process;
Next, a concrete placing process for placing and hardening concrete in the pile hole to form a cast-in-place concrete pile in the ground,
Next, the injection pump includes an injection pump, an injection hose having an upper end connected to the injection pump and a lower end connected to the injection port member, and an injection port member having a lower portion penetratingly connected to the inside of the injection bag body. The injection material is injected into the inside of the bag body, the bottom of the injection bag body is pressed in the pile bottom direction, which is the direction toward the pile bottom, the preload is loaded on the pile tip ground, and the supporting force of the pile tip ground is increased. In the tip preload cast-in-place pile method, which has a preload process that increases and reduces the amount of pile settlement,
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
Have a horizontal discharge portion upper approximate center is connected to the lower end of the vertical pipe portion with only the outflow hole side is opened,
The horizontal discharge part is a horizontal discharge disk part that is formed in a hollow cylindrical shape having a low height, has an outflow hole formed in a cylindrical side surface, and has a substantially upper center connected to a lower end of the vertical pipe part. .

Moreover, the tip preload cast-in-place pile method according to the present invention is
Pile hole drilling process for drilling pile holes for cast-in-place concrete piles in the ground;
Next, a reinforcing bar basket and an injection bag body attached to the lower end of the reinforcing bar basket are set in the pile hole, and the injection bag body is installed so as to face the pile tip ground at the bottom of the pile hole.・ Infusion bag body setting process;
Next, a concrete placing process for placing and hardening concrete in the pile hole to form a cast-in-place concrete pile in the ground,
Next, the injection pump includes an injection pump, an injection hose having an upper end connected to the injection pump and a lower end connected to the injection port member, and an injection port member having a lower portion penetratingly connected to the inside of the injection bag body. The injection material is injected into the inside of the bag body, the bottom of the injection bag body is pressed in the pile bottom direction, which is the direction toward the pile bottom, the preload is loaded on the pile tip ground, and the supporting force of the pile tip ground is increased. A preloading process that increases and reduces pile settlement
In the tip preload cast-in-place pile method,
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
An outlet hole is opened only on the side and a horizontal discharge part is connected to the lower end of the vertical pipe part at the substantially upper center,
The horizontal discharge part has a hollow cylindrical shape with an open upper end and a closed lower end, and has at least one communication port, and at least one horizontal direction so that one end communicates with a communication port on a cylindrical side surface of the central tube. it and the other end opened to the outside a hollow cylindrical projecting ends open is horizontal discharge pipe portion having a radial horizontal tube to be the outlet hole in the
It is characterized by.

  Moreover, in said tip preload cast-in-place pile construction method, Preferably, an uneven | corrugated | grooved part is formed in the outer surface of the said vertical pipe part, and adhesion property with the pile concrete of the pile bottom vicinity is improved.

Moreover, the pile tip preloading device according to the present invention is
An infusion bag body attached to the lower end of the reinforcing steel cage of the cast-in-place concrete pile and set in the pile hole;
An infusion pump, an infusion hose having an upper end connected to the infusion pump and a lower end connected to the infusion port member, and an infusion port member having a lower portion penetratingly connected to the inside of the infusion bag body. Injecting means for injecting the injection material into,
By injecting an injection material into the injection bag body, the bottom of the injection bag body is pressed in the pile bottom direction, a preload is loaded on the pile tip ground, and the supporting force of the pile tip ground is increased and the amount of pile settlement In the pile tip preload device that reduces
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
Have a horizontal discharge portion upper approximate center is connected to the lower end of the vertical pipe portion with only the outflow hole side is opened,
The horizontal discharge part is a horizontal discharge disk part that is formed in a hollow cylindrical shape having a low height, has an outflow hole formed in a cylindrical side surface, and has a substantially upper center connected to a lower end of the vertical pipe part. .

Moreover, the pile tip preloading device according to the present invention is
An infusion bag body attached to the lower end of the reinforcing steel cage of the cast-in-place concrete pile and set in the pile hole;
An infusion pump, an infusion hose having an upper end connected to the infusion pump and a lower end connected to the infusion port member, and an infusion port member having a lower portion penetratingly connected to the inside of the infusion bag body. Injecting means for injecting the injection material into,
By injecting an injection material into the injection bag body, the bottom of the injection bag body is pressed in the pile bottom direction so that a preload is loaded on the pile tip ground to increase the supporting force of the pile tip ground and the amount of pile settlement In the pile tip preload device that reduces
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
A horizontal discharge part where an outflow hole is opened only in the side part and the substantially upper center is connected to the lower end of the vertical pipe part.
Have
The horizontal discharge part has a hollow cylindrical shape with an open upper end and a closed lower end, and has at least one communication port, and at least one horizontal direction so that one end communicates with a communication port on a cylindrical side surface of the central tube. it and the other end opened to the outside a hollow cylindrical projecting ends open is horizontal discharge pipe portion having a radial horizontal tube to be the outlet hole in the
It is characterized by.

  In the above-described pile tip preloading device, preferably, an uneven portion is formed on the outer surface of the vertical pipe portion to enhance adhesion performance with pile concrete near the pile bottom.

  According to the tip preload cast-in-place pile method and the pile tip preload device according to the present invention, a pile hole drilling step of drilling a pile hole for a cast-in-place concrete pile in the ground, then a reinforcing bar cage, and the reinforcing bar cage Reinforcing bag basket / injection bag body setting step of setting the injection bag body attached to the lower end of the pile hole in the pile hole, and setting the injection bag body to face the pile tip ground at the bottom of the pile hole, A concrete casting process in which concrete is cast in the pile hole and hardened to form a cast-in-place concrete pile in the ground, and then the injection pump, the upper end is connected to the injection pump and the lower end is the injection port The injection hose connected to the member and the injection means having the injection port member whose lower part penetrates and connects to the inside of the injection bag body, injects the injection material into the injection bag body, and is directed to the bottom of the pile. Tip preload cast-in-place pile method having a preload step of pressing the bottom of the injection bag body in the bottom direction and loading a preload on the pile tip ground to increase the support force of the pile tip ground and reduce the amount of pile settlement In addition, in the pile tip preloading device used in this construction method, the injection port member is formed in a tubular shape having both ends open in a substantially vertical direction, and a vertical pipe portion whose upper end is connected to the lower end of the injection hose, and a low-profile hollow It is formed in a cylindrical shape with an outflow hole on the side surface of the cylinder and a horizontal discharge disc part that is connected to the lower end of the vertical pipe part at the center of the upper end. Since it can flow in a substantially horizontal direction, the injection material can flow smoothly into the injection bag body, and the injection bag body can be prevented from being clogged or broken due to excessive force. To have. Furthermore, it has the effect that adhesion performance with the pile concrete of the pile bottom vicinity can be improved by forming an uneven | corrugated | grooved part in the outer surface of the said vertical pipe part.

  In the embodiment described below, the injection port member is formed in a hollow tube shape having a low height and a vertical pipe portion that is formed in an open-ended tubular shape extending in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose. An outflow hole is formed on the side surface of the cylinder, and a horizontal discharge disc portion is provided at the center of the upper end that is connected to the lower end of the vertical pipe portion, and an uneven portion is formed on the outer side surface of the vertical pipe portion, and the pile bottom Adhesion performance with nearby pile concrete is improved, and a relatively simple change is made by installing an inlet member at the lower end of the injection hose of the pile tip preload device in the conventional tip preload cast-in-place pile method. Can be easily implemented. In addition, when injecting the injection material for preloading, no special equipment or mechanism is required, and the injection for preloading can be performed by the same injection plant and injection pump as in the past, for realizing the present invention. This is the best configuration.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a tip preload cast-in-place pile method according to a first embodiment of the present invention and a pile tip preload device used in this method.

  As shown in FIG. 1, in the tip preload cast-in-place pile method of this embodiment, first, a pile hole 10 for cast-in-place concrete pile is drilled in the ground (see FIG. 1A). “Pile hole drilling process”.) The hole in the pile hole 10 is water mixed with particles such as bentonite to prevent the pile hole side wall 10a from collapsing (hereinafter referred to as “drilling liquid”). Is performed while filling the pile hole 10. In this case, a slime portion 10c, which is a soft heterogeneous portion in which fine soil particles having been drilled in the ground, are formed at the bottom portion 10b of the pile hole 10 which is the tip (lower end) of the pile.

  Next, the reinforcing bar basket 11 is manufactured in advance outside the pile hole 10. The reinforcing bar basket 11 is assembled into a cylindrical basket shape by binding a plurality of rod-shaped main reinforcing bars arranged in the longitudinal direction and a plurality of hoop reinforcing bars (band reinforcing bars) arranged in a ring shape with a lentil iron wire. A tip preload unit 12 having an infusion bag 1 and a frame 2 to be described later is attached to the lower end of the rebar basket 11, and the rebar basket 11 with the tip preload unit 12 attached to the lower end is suspended by a crane 13 or the like. Sunk into. Thereby, the front-end | tip preload unit 12 is installed so that it may oppose the pile front-end | tip ground of the bottom part 10b of the pile hole 10 (refer FIG.1 (B). Hereinafter, this process is called "reinforcing bar basket and injection bag setting process"). . In addition, since the slime part 10c has settled on the bottom part 10b of the pile hole 10, the injection bag 1 is mounted on the slime part 10c, and opposes the pile front-end ground of the bottom part 10b of the pile hole 10. Installed.

  Here, the tip preload unit 12 will be described. 2 is a diagram showing a more detailed configuration of the tip preload unit 12 in the pile tip preload device 101 shown in FIG. 1, FIG. 2 (A) is a perspective view, FIG. 2 (B) is a sectional view, respectively. Show. 3 is a diagram showing a more detailed configuration of the inlet member in the tip preload unit shown in FIG. 2 and the injection bag and injection hose in the vicinity thereof, and FIG. 3 (A) is a perspective view of the inlet member. FIG. 3B shows a cross-sectional view at this position (a vertical cross-sectional view parallel to the longitudinal direction of the injection hose 17b). Moreover, FIG. 4 is a figure which shows the condition of a reinforcing bar basket and an injection | pouring bag setting process among the procedures of the tip preload cast-in-place pile method shown in FIG. Moreover, FIG. 5 is a conceptual diagram which shows the condition of a preload process among the procedures of the tip preload cast-in-place pile method shown in FIG.

  As shown in FIG. 2, the tip preload unit 12 includes an injection bag 1 and a frame 2.

  The infusion bag 1 is a hollow bag made using a bag body material in which a material having pressure resistance and flexibility is formed into a sheet shape. In this case, the infusion bag 1 is formed into a bag shape by bonding the above-mentioned bag body material with an adhesive, pressure bonding, or heat welding, pressure and heating heat pressure bonding, etc. Not used. Examples of the material constituting the injection bag 1 include synthetic resin materials, for example, plastics such as thermoplastic resins and thermosetting resins, and specifically, polyethylene, polyvinyl chloride, vinylidene chloride, polypropylene, polyamide, and the like. Also, as the bag material, rubber materials (including synthetic rubber and elastomer materials) can be used. Moreover, as a bag body material, the sheet-like member, film-like member, film-like member, etc. which consist of these materials are mentioned. The injection bag 1 is provided with an injection side opening 1e that is a part for attaching the injection port member 4 and a discharge side opening 1f that is a part for attaching the discharge port member 5. The injection bag 1 corresponds to the injection bag body in the claims.

  The frame 2 is made of a material such as metal including steel, and has a plurality of annular portions 2a and a plurality of radial portions 2b that join the annular portions 2a, and is formed in a shape like a colander as a whole. Yes. The frame 2 is disposed between the lower end of the reinforcing bar 11 and the injection bag 1, and the injection bag 1 is fixed to the frame 2 by a fixture 3 such as a steel wire.

  With such a configuration, the lower portion (the bottom portion 1a and the side portion 1b) of the injection bag 1 serving as the bottom portion of the tip preload unit 12 is convex in a direction toward the pile hole bottom portion 10b (hereinafter referred to as “pile bottom direction”). Such as a bowl shape, a hemisphere shape, a paraboloid shape, a truncated cone shape, and the like. For this reason, in the reinforcing bar basket / infusion bag setting step, the resistance force from the drilling liquid when the tip preload unit 12 is set in the pile hole 10 (hereinafter, referred to as “resistance value at the time of setting”) is reduced. (See FIG. 4).

  After the above-described rebar basket / injection bag laying process, the ready-mixed concrete 15a manufactured in a concrete plant (not shown) is poured into the pile hole 10 using the concrete pump 14a and the concrete pumping pipe 14b. Install and cure. As a result, a cast-in-place concrete pile is formed in the ground (see FIG. 1C. Hereinafter, this process is referred to as a “concrete placing process”).

  Next, after confirming that the concrete has hardened and developed a predetermined strength as in 15b, the injection material 17 is injected into the injection bag 1 of the tip preload unit 12 using the injection device 17. The injection device 17 includes a mixer 17m, an injection pump 17a, an injection hose 17b, a discharge hose 17c, an inlet member 4 (see FIGS. 2B and 3), and an outlet member 5 (see FIG. 2). B)), a discharger 17d, valves B1 to B4, and pressure sensors S1 and S2.

  The mixer 17m is provided with a stirring blade or the like inside the container, kneads the input materials (for example, cement, water, additives, etc.), generates an injection material G (for example, cement milk), and supplies it to the injection pump 17a. send. The injection pump 17a is a known pump that applies pressure to the fluid injection material G and pushes it out. The injection pump 17a is installed on the ground near the pile head and sends the injection material G into the injection hose 17b. As the injection material G, a substance that is hardened after being injected in a fluid state is used. In addition to the above-described cement milk, a resin-based injection material or the like is used. The injection hose 17b is a tubular member (pipe) formed of a flexible material, for example, synthetic rubber, rubber-based material, and the like. FIG. 1 (D), FIG. 2 (B), and FIG. ), The upper end thereof is attached to the outlet of the injection pump 17a, and the lower end thereof is connected to one end 4d of the injection port member 4 (hereinafter referred to as “injection hose connection end”).

  Further, the discharge hose 17c is a tubular member (pipe) formed of a flexible material, for example, synthetic rubber, rubber-based material, and the like, as shown in FIGS. 1 (D) and 2 (B), The lower end is connected to the upper end of the discharge port member 5, and the upper end is attached to the inlet of the discharger 17d. 4 and 5, the illustration of the discharge hose 17c is omitted. The discharger 17d is a known pump capable of sucking air, fluid injection material, and the like, and is installed on the ground near the pile head.

  The valves B1 and B2 are valves that can be controlled to be opened and closed by an actuator (not shown) or the like, and are installed in the injection hose 17b (for example, a position sandwiching the pressure sensor S1). The valves B3 and B4 are valves that can be opened and closed by an actuator (not shown) or the like, and are installed in the discharge hose 17c (for example, a position sandwiching the pressure sensor S2). Moreover, the pressure sensor S1 is installed on the ground pile head or the like of the injection hose 17b and detects the pressure in the injection hose 17b. Further, the pressure sensor S2 is installed on a pile head or the like on the ground of the discharge hose 17c and detects the pressure in the discharge hose 17c.

  Using the injection device 17 as described above, for example, first, the valves B1 to B4 are opened, the injection material G is sent from the injection pump 17a, and suction is performed by the discharger 17d. 17b, the inlet member 4, the inlet bag 1, the outlet member 5, and the exhaust hose 17c are exhausted to reach the exhauster 17d. Then, if valve | bulb B4 is obstruct | occluded and the injection material G is sent out from the injection pump 17a in this state, the pressure (injection pressure) of the injection material G in the injection bag 1 will rise. The situation of this injection pressure can be grasped by monitoring the pressure sensors S1 and S2 on the pile head side.

  In the case of the first embodiment, the inlet member 4 is a tubular member made of a hard material, for example, a metal material such as steel or an aluminum alloy, a hard synthetic resin material, a ceramic material, a ceramic material, or the like. The inlet member 4 has a vertical pipe portion 4a and a horizontal discharge disc portion 4b.

  The vertical pipe portion 4a is formed in a circular tube shape whose both ends are open, and is disposed so as to extend in a substantially vertical direction. The injection hose connection end 4d which is the upper end of the vertical pipe portion 4a is connected to the lower end of the injection hose 17b by a short circular hose attachment fitting 7 and an attachment bolt 8.

  Moreover, the horizontal discharge disk part 4b is formed in the hollow cylinder shape with low height. An outflow hole 4c is formed in the cylindrical side surface of the horizontal discharge disc portion 4b. Further, the lower end of the vertical pipe portion 4a is joined to the approximate center of the upper end surface of the horizontal discharge disc portion 4b. The vertical pipe portion 4a and the horizontal discharge disc portion 4b are joined to each other at the center of the upper end surface of the horizontal discharge disc portion 4b, the female screw hole 4h in which the internal thread is formed, and the vertical pipe portion 4a. This is performed by screwing with a male screw portion 4g formed on the outer peripheral surface of the lower end.

  Moreover, the bag attachment recessed part 4e is formed in the outer peripheral surface of the intermediate position of the lower end and upper end of the vertical pipe part 4a. The bag mounting recess 4e is a substantially annular groove. The bag attachment recess 4e is attached to the injection side opening 1e of the injection bag 1 via the injection material leakage preventing packing member 6.

  Moreover, the uneven | corrugated | grooved part 4f is formed in the outer surface near the upper part of the vertical pipe part 4a. The uneven part 4f is formed by arranging a plurality of substantially annular convex parts and grooves alternately. This uneven | corrugated | grooved part 4f exhibits the effect | action similar to a deformed reinforcing bar in concrete, and the adhesion performance of the pile concrete C near the pile bottom and the vertical pipe part 4a is improving. After the injection material is injected into the injection bag 1, a force for pulling out the vertical pipe portion 4 a embedded in the pile concrete C acts with the expansion of the injection bag 1. The adhesion force enhanced by 4f sufficiently resists the pulling force that accompanies the fullness of the infusion bag 1. In addition, the discharge port member 5 has the same configuration as the above-described injection port member 4.

  As described above, the injection material G is injected into the injection bag 1 of the tip preload unit 12. At this time, by providing the inlet member 4 having the outflow hole 4c only on the side portion, the injection material G can always flow in the substantially horizontal direction in the vicinity of the inlet of the injection bag 1. For this reason, the injection material G can be smoothly flowed into the injection bag 1, and “clogging” or breakage of the injection bag 1 due to excessive force can be prevented.

  As described above, the bottom 1a of the injection bag 1 is pressed in the pile bottom direction, and the preload is loaded on the pile tip ground. Along with this, the support force of the pile tip ground is increased and the amount of pile settlement is reduced (see FIG. 1D). Hereinafter, this process is referred to as a “preload process”. Here, the injection device 17 constitutes the injection means in the claims. Moreover, the horizontal discharge disk part 4b of the inlet member 4 is equivalent to the horizontal discharge part in a claim.

  In the above-described preloading process, the injection engineer on the ground can monitor the injection pressure in the injection hose 17b with the pressure sensor S1 and monitor the injection pressure in the discharge hose 17c with the pressure sensor S2.

  Moreover, in the injection bag 1, the packing member 6 for injection material leakage prevention is attached to the injection side opening 1e (refer FIG. 3 (B)). The packing member 6 for preventing injection material leakage has a shape in which a portion protruding downward is joined in the vicinity of the central opening of the flat washer member. Although not shown, the same applies to the discharge-side opening 1f. Thereby, even if a high injection pressure acts, the injection material G does not leak to the outside of the injection bag 1.

  Further, in the above-described rebar basket / infusion bag laying step, the air in the infusion bag 1 is extracted by another exhaust device (not shown) or the like, and the infusion bag 1 is contracted and thin. It has become.

  The pile tip ground is compressed by the preloading process. Thereafter, the injection material G in the injection bag 1 is cured as time passes while maintaining this state. After the injection material G is hardened, even if a structure is built on the top of the pile and the load from the upper structure is applied to the pile, the pile tip ground is pre-compressed by the preload, so the settlement of the pile is suppressed. The

  Further, as shown in FIG. 5B, the frame 2 is formed with a weakened section 21 by a hole, a notch or a reduced section in the radial part 2b, for example, and the sectional weakened part 21 is plastic. It is configured to be deformable. For this reason, when the tip preload unit 12 settles on the pile tip ground of the bottom 10b of the pile hole 10 by the reinforcing bar basket / injection bag laying step, the long axis direction D1 (hereinafter referred to as “pile axis direction”). .)) Acts on the frame 2, for example, the radial portion 2b of the frame 2 is deformed as indicated by 2b 'in FIG. 5B.

  Thereby, the whole flame | frame 2 deform | transforms so that it may collapse in the pile axial direction D1, as shown to FIG. 5 (A). By causing such “crushed deformation” of the frame 2, the depth of the pile hole 10 fluctuates from the design value due to construction errors or the like, and even if the pile hole becomes shallower than the design value, the tip preload unit 12 is accordingly changed. The height can be adjusted. When the injection material G is injected into the injection bag 1, the bottom of the injection bag 1 also presses in the direction D <b> 2 (hereinafter referred to as “pile wall direction”) toward the inner wall 10 a of the pile hole 10. A preload is also loaded on the side of the tip ground (see FIG. 5A).

  Further, since the frame 2 is crushed and deformed, and the side portion of the injection bag 1 is pressed against the inner wall 10a of the pile hole 10, the poured concrete 15a in the fluidized state is placed in the injection bag 1 when the pile concrete 15a is placed. There is no problem of preventing the preload from being applied to the ground of the pile bottom 10b by the hardened concrete without going around the top, and the expansion force of the injection bag 1 is directly applied to the preload on the pile tip ground 10b. It also has the advantage of being able to guess.

  Note that the frame 2 can be configured to be plastically deformable even if it is simply made of a metal material such as a steel material without providing a weakened section (21 or the like).

  The present invention can be realized by other configurations. FIG. 6 shows further details of the tip preload cast-in-place pile method according to the second embodiment of the present invention and the inlet member 4 ′ in the tip preload unit 12 ′ in the injection device 17 ′ of the pile tip preload device 102 used in this method. FIG.

  As shown in FIG. 6, the inlet member 4 'of the second embodiment is a tubular member made of a hard material, for example, a metal material such as steel or aluminum alloy, a hard synthetic resin material, a ceramic material, a ceramic material, or the like. . The inlet member 4 'has a vertical pipe portion 4a and a horizontal discharge pipe portion 4b'. The second embodiment is different from the first embodiment in that it has a horizontal discharge pipe portion 4b 'different from the horizontal discharge disc portion 4b' in the case of the first embodiment. Since the operation is the same as that of the first embodiment, the description thereof is omitted.

  Further, the horizontal discharge pipe portion 4b ′ includes a hollow cylindrical center pipe 4b′0 whose upper end having a low height is opened and whose lower end is closed, and the center side of the center pipe 4b′0 on the cylindrical side surface of the center pipe 4b′0. There are four hollow cylindrical radial horizontal tubes 4b'1 to 4b'4 that are open at both ends and are provided so as to protrude radially in a substantially horizontal direction every 90 degrees. On the cylindrical side surface of the central tube 4b'0, four communication ports 4c'21 to 4c'24 are opened every 90 degrees of the central angle.

  The communication port 4c'21 and one opening of the radial horizontal tube 4b'1 communicate with each other, and the other opening of the radial horizontal tube 4b'1 is connected to the outflow hole 4c'11 opened in the external injection bag 1. It has become. Similarly, one opening of the communication port 4c′22 and the radial horizontal tube 4b′2 communicate with each other, and the other opening of the radial horizontal tube 4b′2 opens to the outside of the infusion bag 1. 4c'12. Similarly, one opening of the communication port 4c'23 and the radial horizontal tube 4b'3 communicates with each other, and the other opening of the radial horizontal tube 4b'3 opens to the outside infusion bag 1. 4c'13. Similarly, one opening of the communication port 4c′24 and the radial horizontal tube 4b′4 communicate with each other, and the other opening of the radial horizontal tube 4b′4 opens to the outside infusion bag 1. 4c'14.

  Moreover, the lower end of the vertical pipe part 4a is joined to the approximate center of the upper end surface of the central pipe 4b'0 of the horizontal discharge pipe part 4b '. The vertical tube portion 4a and the center tube 4b'0 are joined to each other by a female screw hole (not shown) formed in the center of the upper end surface of the center tube 4b'0 and having a female screw formed on the inner wall surface thereof. This is performed by screwing with a male screw portion (not shown) formed on the outer peripheral surface of the lower end of the tube portion 4a.

  As described above, the injection material G is injected into the injection bag 1 of the tip preload unit 12 ′. At this time, by providing the injection port member 4 ′ having the outflow holes 4 c ′ 11 to 4 c ′ 14 only on the side portions, the injection material G can always flow substantially horizontally in the vicinity of the injection port of the injection bag 1. . For this reason, the injection material G can be smoothly flowed into the injection bag 1, and “clogging” or breakage of the injection bag 1 due to excessive force can be prevented.

  In the second embodiment described above, the injection device 17 'constitutes the injection means in the claims. Further, the horizontal discharge pipe portion 4b 'of the inlet member 4' corresponds to the horizontal discharge portion in the claims.

  The present invention is not limited to the above embodiments. Each of the above-described embodiments is an exemplification, and any device that has substantially the same configuration as the technical idea described in the claims of the present invention and has the same operational effects can be used. It is included in the technical scope of the present invention.

  For example, in each of the above embodiments, in the drilling process of the pile hole 10, the example of using the drilling liquid mixed with particles such as bentonite as the means for preventing the collapse of the pile hole side wall has been described. Pile hole drilling process by other methods, for example, pile hole drilling process using casing tube as means for preventing pile hole side wall collapse, hydrostatic pressure used as means for preventing pile hole side wall collapse It may be a pile drilling step or the like. Further, depending on the pile hole drilling process, the slime portion may not be formed at the bottom of the pile hole. In this case, the tip preload unit is directly installed on the bottom of the pile hole.

  Further, in the first embodiment described above, the inlet member 4 is formed in a tubular shape having both ends open in the substantially vertical direction and the upper end is connected to the lower end of the injection hose 17b, and the height is low. An outflow hole 4c is formed on the side surface of the cylinder formed in a hollow cylindrical shape, and a horizontal discharge disc part 4b connected to the lower end of the vertical pipe part 4a is provided at the center of the upper end, and outside the vertical pipe part 4a. Although the structure which formed the uneven | corrugated | grooved part 4f in the side surface and improved the adhesion performance with the pile concrete C near the pile bottom was demonstrated, this invention is not limited to this example. The present invention can also be implemented in a configuration in which the uneven portion 4f is not provided in the inlet member 4 described above.

  Further, in the first embodiment described above, the vertical pipe portion 4a and the horizontal discharge disc portion 4b of the inlet member 4 are joined by the male screw on the vertical pipe portion 4a side and the female screw on the horizontal discharge disc portion 4b side. Although the example performed by this screwing was demonstrated, this invention is not limited to this example. Another structure, for example, a joint by screwing of a female screw on the vertical pipe portion 4a side and a male screw on the horizontal discharge disc portion 4b side may be used. Or joining by welding and joining by an adhesive agent may be sufficient. Further, the entire inlet member 4 may be integrally manufactured by casting, plastic by injection molding using a mold, or the like.

  Also in the second embodiment described above, the joint between the vertical pipe portion 4a of the inlet member 4 'and the horizontal discharge pipe portion 4b' is the center of the male screw on the vertical pipe portion 4a side and the horizontal discharge pipe portion 4b '. Although the example performed by screwing of the female screw on the tube 4b'0 side has been described, the present invention is not limited to this example. Other configurations, for example, joining by screwing of a female screw on the vertical tube portion 4a side and a male screw on the central tube 4b'0 side may be used. Or joining by welding and joining by an adhesive agent may be sufficient. Furthermore, the whole inlet member 4 ′ may be integrally manufactured by casting, plastic by injection molding using a mold, or the like.

  In the second embodiment described above, the example in which the number of radial horizontal tubes is four has been described, but the present invention is not limited to this example. It is sufficient that at least one communication port and radial horizontal tube are provided. When two or more are provided, the central angle of the central tube may not be equally divided.

  INDUSTRIAL APPLICABILITY The present invention can be implemented in a construction industry or the like that constructs a cast-in-place concrete pile as a foundation of a structure or a building, and can be used in these industries. Moreover, the infusion bag body and the infusion bag inner tube for the pile tip preloading device, or the bag body protection member can be manufactured in the plastic industry or the metal industry that manufactures plastic products, metal products, etc. Is available.

It is a figure which shows the structure of the tip preload cast-in-place pile construction method which is 1st Example of this invention, and the pile tip preload apparatus used for this construction method. It is a figure which shows the further detailed structure of the front-end | tip preload unit in the pile front-end | tip preload apparatus shown in FIG. It is a figure which shows the further detailed structure of the inlet member in the front-end | tip preload unit shown in FIG. 2, the injection bag of the vicinity, and an injection hose. It is a figure which shows the condition of a reinforcing bar basket and injection bag setting process among the procedures of the tip preload cast-in-place pile method shown in FIG. It is a conceptual diagram which shows the condition of a preload process among the procedures of the tip preload cast-in-place pile construction method shown in FIG. It is a perspective view which shows the more detailed structure of the inlet port member in the front-end | tip preload unit in the front-end | tip preload cast-in-place pile construction method which is 2nd Example of this invention, and the pile front-end | tip preload apparatus used for this construction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection bag 1a Bottom part 1b Side part 1c Upper part 1e Injection side opening 1f Discharge side opening 2 Frame 2a Annular part 2b, 2b 'Radial part 3 Fixing tool 4, 4' Inlet member 4a Vertical pipe part 4b Horizontal discharge disk part 4b ' Horizontal discharge pipe section 4b'0 Central pipe 4b'1 to 4b'4 Radial horizontal pipe 4c, 4c'11 to 4c'14 Outflow hole 4c'21 to 4c'24 Communication port 4d Injection hose connection end 4e Bag mounting recess 4f Unevenness Part 4g Male thread part 4h Female thread hole 6 Packing member for injection material leakage prevention 7 Hose mounting bracket 8 Mounting bolt 10 Pile hole side wall 10b Pile hole side wall 10b Pile hole bottom part 10c Slime part 11 Reinforcing bar cage 12, 12 'Tip preload unit 13 Crane 14a Concrete pump 14b Concrete pumping pipe 15a Ready-mixed concrete 15b Concrete after hardening 17, 1 'Injection device 17a infusion pump 17b injection hose 17c drain hose 17d discharger 17m mixer 21 cross weakening 101 and 102 pile tip preloading device C piles Concrete D1 pile bottom direction D2 Kuikabe direction G injection material S1, S2 pressure sensor

Claims (6)

Pile hole drilling process for drilling pile holes for cast-in-place concrete piles in the ground;
Next, a reinforcing bar basket and an injection bag body attached to the lower end of the reinforcing bar basket are set in the pile hole, and the injection bag body is installed so as to face the pile tip ground at the bottom of the pile hole.・ Infusion bag body setting process;
Next, a concrete placing process for placing and hardening concrete in the pile hole to form a cast-in-place concrete pile in the ground,
Next, the injection pump includes an injection pump, an injection hose having an upper end connected to the injection pump and a lower end connected to the injection port member, and an injection port member having a lower portion penetratingly connected to the inside of the injection bag body. The injection material is injected into the inside of the bag body, the bottom of the injection bag body is pressed in the pile bottom direction, which is the direction toward the pile bottom, the preload is loaded on the pile tip ground, and the supporting force of the pile tip ground is increased. In the tip preload cast-in-place pile construction method that has a preload process that increases and reduces pile settlement,
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
Have a horizontal discharge portion upper approximate center is connected to the lower end of the vertical pipe portion with only the outflow hole side is opened,
The horizontal discharge part is a horizontal discharge disk part that is formed in a hollow cylindrical shape having a low height, has an outflow hole formed in a cylindrical side surface, and has a substantially upper center connected to a lower end of the vertical pipe part. Tip preload cast-in-place pile method. Pile hole drilling process for drilling pile holes for cast-in-place concrete piles in the ground;
Next, a reinforcing bar basket and an injection bag body attached to the lower end of the reinforcing bar basket are set in the pile hole, and the injection bag body is installed so as to face the pile tip ground at the bottom of the pile hole.・ Infusion bag body setting process;
Next, a concrete placing step of placing and hardening concrete in the pile hole to form a cast-in-place concrete pile in the ground, and
Next, the injection pump includes an injection pump, an injection hose having an upper end connected to the injection pump and a lower end connected to the injection port member, and an injection port member having a lower portion penetratingly connected to the inside of the injection bag body. The injection material is injected into the inside of the bag body, the bottom of the injection bag body is pressed in the pile bottom direction, which is the direction toward the pile bottom, the preload is loaded on the pile tip ground, and the supporting force of the pile tip ground is increased. A preloading process that increases and reduces pile settlement
In the tip preload cast-in-place pile method,
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
A horizontal discharge part where an outflow hole is opened only in the side part and the substantially upper center is connected to the lower end of the vertical pipe part.
Have
The horizontal discharge part has a hollow cylindrical shape with an open upper end and a closed lower end, and has at least one communication port, and at least one horizontal direction so that one end communicates with a communication port on a cylindrical side surface of the central tube. A tip preload cast-in-place pile method, characterized in that it is a horizontal discharge pipe part having a hollow horizontal cylindrical shape projecting on both ends and having a radial horizontal pipe with the other end opened to the outside serving as an outflow hole . In the tip preload cast-in-place pile method according to claim 1 or 2 ,
The tip preload cast-in-place pile method is characterized in that an uneven portion is formed on the outer surface of the vertical pipe portion, and the adhesion performance with pile concrete near the pile bottom is enhanced . An infusion bag body attached to the lower end of the reinforcing steel cage of the cast-in-place concrete pile and set in the pile hole;
An infusion pump, an infusion hose having an upper end connected to the infusion pump and a lower end connected to the infusion port member, and an infusion port member having a lower portion penetratingly connected to the inside of the infusion bag body. Injecting means for injecting the injection material into,
By injecting an injection material into the injection bag body, the bottom of the injection bag body is pressed in the pile bottom direction, a preload is loaded on the pile tip ground, and the supporting force of the pile tip ground is increased and the amount of pile settlement In the pile tip preload device that reduces
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
An outlet hole is opened only on the side and a horizontal discharge part is connected to the lower end of the vertical pipe part at the substantially upper center,
The horizontal discharge part is a horizontal discharge disk part that is formed in a hollow cylindrical shape having a low height, has an outflow hole formed in a cylindrical side surface, and has a substantially upper center connected to a lower end of the vertical pipe part. Pile tip preloading device. An infusion bag body attached to the lower end of the reinforcing steel cage of the cast-in-place concrete pile and set in the pile hole;
An infusion pump, an infusion hose having an upper end connected to the infusion pump and a lower end connected to the infusion port member, and an infusion port member having a lower portion penetratingly connected to the inside of the infusion bag body. Injecting means for injecting the injection material into,
By injecting an injection material into the injection bag body, the bottom of the injection bag body is pressed in the pile bottom direction so that a preload is loaded on the pile tip ground to increase the supporting force of the pile tip ground and the amount of pile settlement In the pile tip preload device that reduces
The inlet member is
A vertical pipe part that is formed in a tube open at both ends that extends in a substantially vertical direction and whose upper end is connected to the lower end of the injection hose;
An outlet hole is opened only on the side and a horizontal discharge part is connected to the lower end of the vertical pipe part at the substantially upper center,
The horizontal discharge part has a hollow cylindrical shape with an open upper end and a closed lower end, and has at least one communication port, and at least one horizontal direction so that one end communicates with a communication port on a cylindrical side surface of the central tube. A pile tip preloading device, characterized in that it is a horizontal discharge pipe part having a hollow horizontal cylindrical shape projecting on both ends and having a radial horizontal pipe with the other end opened to the outside serving as an outflow hole . In the pile tip preloading device according to claim 4 or 5,
The pile tip preloading device is characterized in that an uneven portion is formed on the outer surface of the vertical pipe portion to improve the adhesion performance with the pile concrete near the pile bottom .

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