JP2008297864A - Construction method of cast-in-place pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method of a cast-in-place pile that can carry out previous boring and pile driving in one step and carry out construction even with obstacles such as boulder stones. <P>SOLUTION: This construction method of the cast-in-place pile comprises removing soil while forming an excavated hole 2 in the ground 1 with a casing pipe 52 provided with an outer bit 51 at the tip, an inner rod 62 provided with an inner bit 61 at the tip, and boring water W, inserting the casing pipe 52 into the ground 1, pulling out the inner rod 62 in the state of the casing pipe 52 remaining in the excavated hole 2 after forming the excavated hole 2, injecting a predetermined amount of solidifying filler 3 into the casing pipe 52 from an injection pipe 7, and then pulling out the casing pipe 52 by the approximately same section as the injected section of the solidifying filler 3 to replace the soil in the ground 1 with the solidifying filler. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for constructing a cast-in-place pile that can perform preceding drilling and pile driving in one step and that can be constructed even if there are obstacles such as rolling stones.

  Conventionally, before constructing a building, the ground of the relevant place is investigated, the Swedish soiling method, the borehole survey, etc. are investigated, and the survey is concerned about the uneven settlement of the building on embankment or soft ground. In some cases, the foundation will be reinforced. And as a method of foundation reinforcement, a solidified material is added to the ground surface, and the surface layer is improved by stirring with a backhoe or the like to harden the soft ground. Also, for example, using a stirring blade having a diameter of about 500 mm, the slurry-like solidified material is ground. The columnar improvement which stirs while adding to and produces a cylindrical improvement body is mentioned. In addition, a method of using a steel pipe pile that inserts a ready-made steel pipe into the ground by rotary press-fitting and hitting and reaches the support layer, or press-fit and hit a ready-made RC (reinforced concrete) pile or PC (prestressed concrete) pile ( A method of inserting the ground into the ground by (vibration) or the like is also included.

  However, in the above-mentioned surface layer improvement, the improvement thickness which can be constructed is less than about 1 m of the surface layer, and when the reinforcement extends beyond that, the construction becomes difficult. And it is easily influenced by the weather such as rain during construction, and there is a problem that stirring with the solidified material becomes difficult in strong viscous ground. In the above-described columnar improvement, the strength of the improved body is relatively soft, and if there are obstacles such as rolling stones in the ground, the construction becomes difficult. In addition, there is a problem that stirring with a solidified material becomes difficult in strong viscous ground. In the method using the steel pipe pile described above, it takes time and labor for the welded joint of the pile, and when the support layer is very deep, the pile length becomes long and the construction cost is high. In the method using the RC pile or the PC pile described above, if there is an obstacle such as a boulder in the ground, pre-boring is required, which requires labor. And when these piles are press-fitted, hammered (vibrated), etc., if the force is applied to the piles, there is a problem that these piles are damaged. Therefore, the following cast-in-place pile construction methods have been devised to solve these problems.

  Then, as shown in FIG. 15, as a construction method of the cast-in-place pile 100, (a) a process of digging up to a predetermined position with the auger 101, (b) standing the steel pipe pipe concrete formwork 102 with the pile driving machine 103. (C) A step in which the steel pipe pipe concrete mold 102 is rotated, vibrated, press-fitted, etc., embedded to a predetermined position, and then a steel bar pipe concrete mold 102 is filled with rebar as necessary to place the concrete 104. (D) The step of separating the end cap 105 immediately after placement of the concrete coolant 104 and lifting the steel pipe pipe concrete formwork 102 while applying rotational vibration to the steel pipe pipe concrete formwork 102, (e) completely pulling out the steel pipe pipe concrete formwork 102 and removing the concrete 104 A curing step (for example, Patent Document 1).

Japanese Utility Model Publication No. 2000-297430

  However, in the conventional method as shown in FIG. 15, it is necessary to make a pre-drilling with the auger 101 at a place where the steel pipe-pipe concrete formwork 102 is stood in advance, which takes time and effort. Further, when the screw auger 101 is used, there is a problem that excavation is difficult when there is a rock or the like in the ground. Furthermore, when the steel pipe cap is equipped with blades for excavation, there is a possibility that a problem such as bending of the steel pipe pipe concrete formwork 102 itself may occur when the blade comes into contact with an obstacle such as a rolling stone. .

  The present invention has been made for the purpose of solving the various problems as described above, and can perform the pre-drilling and pile driving in one step, and has a strong viscous ground, support layer. The present invention relates to a method for constructing cast-in-place piles that can be constructed easily and economically even when there are obstacles such as rocks in the ground.

  In order to achieve the above object, a method for constructing a cast-in-place pile according to claim 1 is a cast-in-place pile in which a solidified filler is placed in an excavation hole formed in the ground, and the pile is constructed in the ground at the site. A method for constructing a pile, wherein the excavation hole is formed in a substantially vertical direction in the ground by a cylindrical casing pipe having an outer bit at its tip and drilling water supplied to the inside of the casing pipe. Waste soil, the casing pipe is inserted into the ground, after the excavation hole is formed, a predetermined amount of the solidified filler is injected into the casing pipe from the injection pipe inserted into the casing pipe, The casing pipe is pulled out only in a section substantially the same as the section in which the solidified filler is injected, and the soil in the ground and the solidified filler are replaced.

  The construction method of the cast-in-place pile according to claim 2 is characterized in that the ground is excavated while applying a rotational force and a striking force to the casing pipe.

  The construction method of the cast-in-place pile according to claim 3 is a cast-in-place pile construction method in which the solidified filler is placed in the excavation hole formed in the ground, and the pile is constructed in the ground at the site, A cylindrical casing pipe having an outer bit at its tip, an inner rod having an inner bit inserted into the tip of the casing pipe at its tip, and drilling water supplied to the inside of the inner rod The waste soil is formed while forming the excavation hole in a direction substantially perpendicular to the ground, and the casing pipe is inserted into the ground, and after the formation of the excavation hole, the casing pipe is left in the excavation hole. The inner rod is pulled out from the inside of the casing pipe, and a predetermined amount of the solidified filling is filled into the casing pipe from an injection pipe inserted into the casing pipe. After injection of only substantially the same period and interval solid packing material is injected withdrawn the casing pipe, it is characterized by replacing the soil in said ground and said solidifying filler.

  The construction method of the cast-in-place pile according to claim 4 is characterized in that the ground is excavated while a rotational force and a striking force are applied to the casing pipe and the inner rod.

  The cast-in-place pile construction method according to claim 5 is characterized in that a diameter of the cast-in-place pile is 300 mm or less.

  According to the construction method of the cast-in-place pile according to claim 1, the ground is excavated by the cylindrical casing pipe having an outer bit at the tip thereof and the drilling water supplied to the inside of the casing pipe. . Therefore, even if there are obstacles such as rolling stones in the ground, the ground can be excavated through the obstacles, and problems such as bending of the casing pipe hardly occur. Furthermore, since drilling water is used, the ground can be excavated with the drilling water, and the drilling can be performed while softening the ground with the drilling water, thereby efficiently forming the drilling hole. can do. Further, as described above, while excavating the ground with the outer bit, the soil after the excavation can be discarded to the ground with drilling water. And while excavating the ground with the casing pipe itself, the casing pipe can be inserted into the ground at the same time as excavation, so that the pre-drilling and pile driving can be performed in one step. Then, after injecting a predetermined amount of the solidified filler into the excavation hole, the casing pipe inserted into the excavation hole is pulled out only in a section substantially the same as the section into which the solidified filler has been injected. The solidified filler can be injected into the excavation hole without the wall surface collapsing. Furthermore, instead of mixing the soil of the ground and the solidified filler to form the cast-in-place pile, the cast-in-place pile is formed by replacing the soil of the ground and the solidified filler, so the soil of the ground Since the strength of the pile itself is increased compared with the case of mixing with a solidified filler such as cement milk, even a small-diameter pile can withstand a large load. And even if it is a strong viscous ground, it can respond. Moreover, even when the support layer is deep, the construction cost can be reduced as compared with the case where a ready-made steel pipe pile is used. Therefore, it is simple and economical, and the foundation of the ground can be reliably reinforced.

  According to the construction method of the cast-in-place pile according to claim 2, in addition to the above-described effect, the ground is excavated while applying a rotational force and a striking force to the casing pipe. Therefore, even if there is a stronger obstacle such as a boulder in the ground, it is possible to easily form a drilling hole, and it is possible to reduce the time required to form the drilling hole in the ground.

  According to the construction method of the cast-in-place pile according to claim 3, a cylindrical casing pipe having an outer bit at its tip, and an inner rod having an inner bit inserted into the tip of the casing pipe at its tip. The ground is excavated by the drilling water supplied into the inner rod. Therefore, even if there are obstacles such as stronger rocks in the ground, the ground can be excavated through the obstacles, and problems such as bending of the casing pipe hardly occur. Furthermore, since drilling water is used, the ground can be excavated with the drilling water, and the drilling can be performed while softening the ground with the drilling water, thereby efficiently forming the drilling hole. can do. Further, as described above, while excavating the ground with the outer bit and the inner bit, the soil after the excavation can be discarded to the ground with drilling water. And the ground can be excavated with the casing pipe itself, the inner rod can be pulled out after forming the excavation hole, and the casing pipe can be inserted into the ground at the same time as excavation. Can be performed in one step. In addition, after injecting a predetermined amount of the solidified filler into the drilling hole, the casing pipe inserted into the drilling hole is pulled out only in a section substantially the same as the section into which the solidified filler has been injected. The solidified filler can be injected into the excavation hole without the wall surface collapsing. Furthermore, instead of mixing the soil of the ground and the solidified filler to form the cast-in-place pile, the cast-in-place pile is formed by replacing the soil of the ground and the solidified filler, so the soil of the ground Since the strength of the pile itself is increased compared with the case of mixing with a solidified filler such as cement milk, even a small-diameter pile can withstand a large load. And even if it is a strong viscous ground, it can respond. Moreover, even when the support layer is deep, the construction cost can be reduced as compared with the case where a ready-made steel pipe pile is used. Therefore, it is simple and economical, and the foundation of the ground can be reliably reinforced.

  According to the construction method of the cast-in-place pile according to claim 4, in addition to the above-mentioned effect, the ground is excavated while applying a rotational force and a striking force to the casing pipe and the inner rod. . Therefore, even if there is a more solid obstacle such as a boulder in the ground, a drilling hole can be easily formed, and the time required to form a drilling hole in the ground can be further shortened. .

  According to the construction method of the cast-in-place pile according to claim 5, since the diameter of the cast-in-place pile is 300 mm or less in addition to the above-described effect, it is suitable for foundation reinforcement of a detached house, Since the heavy machinery used can be a small one, it is possible to enter a relatively narrow passage or the like. Furthermore, as described above, these piles are formed so as to replace the soil in the ground and the solidified filler, so that the pile is formed by mixing the soil in the ground and the solidified filler. In comparison, the strength of the pile itself is increased, and even a small diameter can withstand a large load.

  The best embodiment of the construction method of the cast-in-place pile in this invention is demonstrated below. As shown in FIG. 14 (b), the cast-in-place pile construction method according to the present invention places a solidified filler 3 in an excavation hole 2 formed in the ground 1, and piles the ground 1 in the ground at the site. As shown in FIG. 5, a cylindrical casing pipe 52 having an outer bit 51 at its tip, and an inner portion inserted into the tip of the casing pipe 52, as shown in FIG. The inner rod 62 having a bit 61 at the tip thereof and the drilling water W supplied into the inner rod 62 are discarded while forming the excavation hole 2 in the substantially vertical direction in the ground 1, and After the casing pipe 52 is inserted into the ground 1 and the excavation hole 2 is formed, the inner rod 62 is inserted into the casing with the casing pipe 52 remaining inside the excavation hole 2 as shown in FIG. After pulling out from the inside of the single pipe 52 and, as shown in FIGS. 8, 9, and 10, after injecting a predetermined amount of the solidified filler 3 into the casing pipe 52 from the injection pipe 7 inserted into the casing pipe 52 The casing pipe 52 is pulled out only in a section substantially the same as the section in which the solidified filler 3 is injected, so that the soil in the ground 1 and the solidified filler 3 are replaced. In addition, as described above, the inner rod 62 is not used, and the excavation hole 2 is formed by the outer bit 51 and the drilling water W supplied into the outer bit 51 as shown in FIG. Good.

  The cast-in-place pile 4 is different from a prefabricated pile construction method in which a steel pipe pile, a RC (steel reinforced concrete) pile or a PC (prestressed concrete) pile prepared in advance is inserted into the ground 1. 2 and the pile 4 created in the ground 1 by injecting the solidified filler 3 into the excavation hole 2. Furthermore, the cast-in-place pile 4 in the present invention is different from the columnar improvement method in which the soil in the ground 1 and the solidified filler 3 are mixed and stirred to form a pile in the ground 1, and the ground in which the excavation hole 2 is formed. The soil in 1 is completely abandoned and piles 4 are formed in the ground 1. That is, the pile 4 is formed in the ground 1 so as to replace the soil in the ground 1 and the solidified filler 3. And the ground 1 is reinforced by forming the several cast-in-place pile 4 in the ground 1 in the said location which constructs a building, and this building is constructed above it. In addition, when used in a detached house or the like, a small heavy machine 8 can be used and a relatively narrow passage can be passed, so that the diameter of the cast-in-place pile 4 is about 300 mm or less. Is preferable, and it is more preferable that it is 200 mm or less. However, even if the diameter of the cast-in-place pile 4 is larger than about 300 mm, it is a matter of course that the cast-in-place pile 4 construction method of the present invention can be used and the same effect can be exhibited. . As the solidified filler 3 used in the present embodiment, cement milk not using aggregate, mortar using fine aggregate of about 1 mm, for example, can be preferably used. The thickness is not limited to these, and can be appropriately changed according to the purpose.

  As shown in FIG. 3, the outer bit 51 is formed with a bit 51b for excavating the ground 1 at the tip 51a. Further, a screw groove 51c is formed on the outer peripheral surface of the outer bit 51 opposite to the side on which the bit 51b is formed, and a screw groove 52b formed on the inner peripheral surface of the distal end portion 52a of the casing pipe 52 described later. And can be screwed together. Further, the entire outer bit 51 or the tip portion 51a is formed of a hard metal such as tungsten, and diamond particles are cast when the outer bit 51 is formed. As shown in FIG. 14, an obstacle I such as a boulder in the ground 1 can be easily penetrated. In addition, the overall shape of the outer bit 51 used in the present embodiment is provided with a bit 51b at a tip portion 51a of a substantially cylindrical body portion, and a screw groove 51c on the opposite side. However, the outer bit 51 may have any shape as long as at least an inner rod 62 described later can be inserted therein, and the shape of the bit 51b is not limited to that of the present embodiment.

  As shown in FIG. 3, the casing pipe 52 is a long cylindrical steel member. A screw groove 52 b for screwing with the outer bit 51 described above is formed on the inner peripheral surface of the tip end portion 52 a of the casing pipe 52. In the present embodiment, screw grooves 51 c and 52 b are formed on the outer peripheral surface of the outer bit 51 and the inner peripheral surface of the casing pipe 52 so as to be screwed together. Screw grooves 51c and 52b may be formed on the outer surface of the casing pipe 52 and the outer surface of the casing pipe 52. Further, in other methods, the outer bit 51 is not dropped from the casing pipe 52 while excavating the ground 1. If it is. Moreover, since the casing pipe 52 is formed to be about 1 m, for example, a plurality of casing pipes 52 can be connected and used by using a connecting member (not shown) as appropriate. And the side opposite to the side where the outer bit 51 is attached in the casing pipe 52, that is, the ground side of the casing pipe 52 is connected to the heavy machine 8 as shown in FIG.

  As shown in FIG. 4, the inner bit 61 is formed with a bit 61b for excavating the ground 1 at the tip portion 61a. Further, a screw groove 61c is formed on the outer peripheral surface of the inner bit 61 opposite to the side on which the bit 61b is formed, and a screw groove 62b formed on the inner peripheral surface of the distal end portion 62a of the inner rod 62 described later. And can be screwed together. Further, the entire inner bit 61 or the tip portion 61a is formed of a hard metal such as tungsten, and diamond grains are cast when the inner bit 61 is formed. Obstacles I such as boulders in 1 can be easily penetrated.

  The overall shape of the inner bit 61 used in the present embodiment is provided with a bit at the tip portion 61a of the substantially cylindrical body portion, and a screw groove 61c on the opposite side. As shown in FIG. 5, the inner bit 61 is formed with a flow path 9 through which the drilling water W and the like to be described later pass. Further, as shown in FIGS. 4 and 5, the flow path 9 is formed so as to communicate from the upper part of the inner bit 61 to the opening 10 formed at each of the tip and the side part through the inside thereof. The drilling water W or the like can be ejected from the opening 10. However, the inner bit 61 may have any shape as long as it has at least the flow passage 9 for passing the drilled water W, and the shape of the bit is not limited to that of the present embodiment. .

  As shown in FIG. 4, the inner rod 62 is a long cylindrical steel member. A screw groove 62b for screwing with the inner bit 61 described above is formed on the inner peripheral surface of the tip end portion 62a of the inner rod 62. In this embodiment, screw grooves 61 c and 62 b are formed on the outer peripheral surface of the inner bit 61 and the inner peripheral surface of the inner rod 62 so as to be screwed together. Screw grooves 61c and 62b may be formed on the outer surface of the inner rod 62 and the inner rod 62. Further, a connecting method that prevents the inner bit 61 from falling off from the inner rod 62 during excavation of the ground 1 is also possible. If it is. Further, since the inner rod 62 is formed to have a thickness of about 1 m, for example, a plurality of inner rods 62 are connected by using a connecting member (not shown) as appropriate. The opposite side of the inner rod 62 to the side on which the inner bit 61 is attached, that is, the ground side of the inner rod 62 is connected to the heavy machine 8 as shown in FIG.

  A construction method of the cast-in-place pile 4 using the casing pipe 52 and the inner rod 62 formed as described above will be described below.

[Drilling process]
First, as shown in FIG. 1, the above-described casing pipe 52 and inner rod 62 are attached to the heavy machinery 8, and the excavation hole 2 is formed in a substantially vertical direction in the ground 1 of the location where the building is to be constructed. At that time, as shown in FIG. 2, the inner bit 61 attached to the tip of the inner rod 62 is attached to the heavy machine 8 so as to protrude slightly from the outer bit 51 attached to the tip of the casing pipe 52. However, the outer bit 51 may protrude. When the excavation hole 2 is formed in the ground 1, the rotational force and the striking force are applied to both the casing pipe 52 and the inner rod 62 by applying the rotational force and the striking force. The ground bit 1 is efficiently excavated by being transmitted to the outer bit 51 and the inner bit 61 attached to the tip. Therefore, a small rotary percussion drill or the like that can enter a relatively narrow passage can be suitably used as the heavy machine 8, but a general-purpose boring machine or the like can also be used.

  And when excavating the ground 1 with the casing pipe 52 and the inner rod 62 as mentioned above, the drilling water W is poured into the inner rod 62 from the ground as shown in FIG. Then, the drilling water W injected from the ground advances in the direction of the tip of the inner rod 62 which is the direction of arrow A shown in FIG. It is injected from the opening 10 formed at the tip and side of the inner bit 61 through. As described above, the drilling water W sprayed from the inner bit 61 excavates the ground 1 or softens the ground 1 with the pressure, and improves excavation efficiency by the inner bit 61 and the outer bit 51.

  Further, the drilling water W ejected from the opening 10 of the inner bit 61 then passes through the gap between the inner bit 61 and the outer bit 51 in the direction of arrow C as shown in FIG. It passes through the gap with the casing pipe 52 in the direction of arrow D and is then discharged to the ground. At that time, the soil of the ground 1 excavated by the inner bit 61, the outer bit 51, and the drilling water W is discarded together with the drilling water W to the ground. Then, after the ground 1 is excavated and the excavation hole 2 is formed as described above, the inside of the excavation hole 2, the casing pipe 52, and the inner rod 62 is filled with the drilling water W, The soil and the drilling water W are replaced.

  In addition, as described above, when excavation is performed using only the casing pipe 52 including the outer bit 51 without using the inner rod 62 including the inner bit 61, the casing pipe is formed from the ground as shown in FIG. Drilling water W is injected into 52, and the drilling water W travels in the S direction, which is the tip direction of the casing pipe 52, and is then sprayed from the tip portion of the outer bit 51. As described above, the drilling water W sprayed from the outer bit 51 excavates the ground 1 with the pressure, or softens the ground 1 and improves the excavation efficiency by the outer bit 51. At this time, a rotational force and a striking force are applied to the casing pipe 52.

  Then, the drilling water W sprayed from the tip of the outer bit 51 passes through the gap between the outer bit 51, the casing pipe 52, and the inner peripheral surface 2a of the excavation hole 2 as shown in FIG. Pass through in the direction and then discharged to the ground. At that time, the soil of the ground 1 excavated by the outer bit 51 and the drilling water W is discarded together with the drilling water W on the ground. Then, after the ground 1 is excavated and the excavation hole 2 is formed as described above, the inside of the excavation hole 2 and the casing pipe 52 is filled with the drilling water W, and the soil and the drilling water in the ground 1 are filled. W is replaced.

  Further, the drilling water W inside the drilling hole 2 will be described later by a method in which the drilling water W and the solidified filler 3 are replaced. The excavated soil remaining in 2 may be discharged to the ground with a compressor or the like after completion of drilling, or air may be pressed into the injection pipe 7 from the ground and discharged to the ground. As described above, the excavation hole 2 is formed in the ground 1 in a substantially vertical direction.

[Drawing process]
Then, after the excavation hole 2 is formed as described above, the inner rod 62 is inserted into the casing pipe 52 in a state where the casing pipe 52 remains in the excavation hole 2 in the direction of arrow G shown in FIG. Pull out from. Further, as described above, when the inner rod 62 having the inner bit 61 is not used, this step is not necessary.

[Solidified filler injection process]
Next, as shown in FIG. 8, an injection pipe 7 for injecting the solidified filler 3 into the excavation hole 2 from the ground is inserted into the casing pipe 52. At that time, the injection tube 7 is inserted so that the tip of the injection tube 7 reaches the vicinity of the bottom of the excavation hole 2 so that the solidified filler 3 can be injected from the bottom of the excavation hole 2. It is preferable. When injecting the solidified filler 3 into the excavation hole 2, after injecting the solidified filler 3 by a predetermined amount into the casing pipe 52, only a section substantially similar to the section into which the solidified filler 3 has been injected. The casing pipe 52 is pulled out. That is, as shown in FIG. 9, the solidified filler 3 is injected from the ground by a predetermined amount into the casing pipe 52 while the casing pipe 52 remains in the excavation hole 2. Then, as shown in FIG. 10, the casing pipe 52 is pulled out in the direction of the arrow H for a predetermined interval. By doing so, the inner peripheral surface 2 a of the excavation hole 2 protected by the casing pipe 52 is now protected by the solidified filler 3. That is, since the specific gravity of the solidified filler 3 such as mortar and cement milk is large, the inner peripheral surface 2a of the excavation hole 2 is protected by the pressure exerted by the solidified filler 3 on the inner peripheral surface 2a of the excavation hole 2. The inner peripheral surface 2a of the excavation hole 2 does not collapse. Further, instead of the method as described above, the solidified filler 3 may be injected from the ground by a predetermined amount after the casing pipe 52 has been drawn out for a predetermined section first.

  Then, when the solidified filler 3 is injected from the injection pipe 7 into the excavation hole 2, the inside of the excavation hole 2 is filled with the drilling water W. By injecting the solidified filler 3, the specific gravity is increased. The solidified filler 3 having a large diameter is replaced with the drilling water W from the bottom of the excavation hole 2. Further, the drilling water W replaced with the solidified filler 3 as described above is discharged from the ground. Then, the solidified filler 3 is continuously injected into the excavation hole 2, and the injection operation is performed until the drilling water W discharged from the ground becomes the solidified filler 3 as described above. By doing so, the inside of the excavation hole 2 filled with the drilling water W can be filled with the solidified filler 3 with the casing pipe 52 completely pulled out. That is, the cast-in-place pile 4 can be constructed so as to replace the soil of the ground 1 and the solidified filler 3. As described above, the solidified filler 3 is injected into the excavation hole 2. Further, in this process, the same operation is performed without changing whether or not the inner rod 62 including the inner bit 61 is used.

  As described above, the solidified filler 3 injected into the excavation hole 2 is cured for a predetermined time, whereby the solidified filler 3 is cured and the cast-in-place pile 4 is formed.

  Further, when injecting the solidified filler 3 into the excavation hole 2, the solidified filler 3 is pressurized and injected into the excavation hole 2 by covering the upper portion of the casing pipe 52 or using a packer. Thus, as shown in FIG. 11, in addition to the large specific gravity of the solidified filler 3, pressure acts in the direction of the arrow X, which is the direction of the inner peripheral surface 2a of the excavation hole 2, so that the inner peripheral surface 2a The solidified filler 3 invades the gap between the ground 1 at the bottom, and the proof strength of the pile 4 can be further improved. Moreover, since the pressure which the solidification filler 3 exerts on the inner peripheral surface 2a increases by performing pressure injection as described above, there is also an advantage that the inner peripheral surface 2a does not collapse during construction.

  Moreover, after injecting the solidified filler 3 into the excavation hole 2, before the solidified filler 3 is hardened, as shown in FIG. 12, a reinforcing bar, square pipe, pipe pipe, H steel, etc. The core material 11 may be inserted, whereby the proof strength of the pile 4 can be further improved. As shown in FIG. 12 (a), the core 11 may have a length from the ground to the bottom of the excavation hole 2, but as shown in FIG. 12 (b), for example, the ground 1 to 2 mm in length may be used.

  Then, after injecting the solidified filler 3 into the excavation hole 2, before the solidified filler 3 is cured, a substantially cylindrical protective member 12 may be inserted from the ground as shown in FIG. 13 (a). . Thereby, while being able to specify the position of the pile 4, there exists an advantage that a pile head can be protected. Further, when the pile 4 is formed so as to protrude from the ground level, the protective member 12 is inserted so as to protrude from the ground level as shown in FIG. These can be formed by injecting the solidified filler 3 into the inside 12. Further, the protective member 12 may not be substantially cylindrical as in the present embodiment, but may be a prism, and further may be a reinforcing bar rod, and the shape thereof can be appropriately changed according to the purpose. .

  According to the construction method of the cast-in-place pile 4 as described above, the pre-drilling and the pile placement can be performed in one process, the strong viscous ground, the ground with a deep support layer, As shown in FIG. 14 (a), even if there is an obstacle I such as a boulder in the ground, as shown in FIG. 14 (b), the cast-in-place pile 4 is constructed so as to penetrate the obstacle I. Can do it.

  The construction method of the cast-in-place pile 4 according to the present invention can be used not only for foundation reinforcement for building construction but also for reinforcement of inclined surfaces such as slopes and as a landslide suppression pile.

The figure which shows excavation by the heavy machinery concerning this embodiment The perspective view of the usage example of the inner bit and outer bit which concern on this embodiment The figure which shows the outer bit which concerns on this embodiment, and a casing pipe The figure which shows the inner bit which concerns on this embodiment, and an inner rod The figure which shows the state which excavates the ground The figure which shows the state where the inner rod is pulled out with the casing pipe remaining in the excavation hole Diagram showing the state of excavating the ground without using the inner bit The figure which shows the state which inserted the injection pipe inside the casing pipe left in the excavation hole The figure which shows the state which inject | pours the solidification filler into a casing pipe inside The figure which shows the state which pulled out the casing pipe from the state of FIG. The figure which shows the state of a pile when solidified filler is pressure-injected The figure which shows the state which inserted the core material into the pile The figure which shows the state which inserted the protection member in the pile The figure which shows the state where the cast-in-place pile was formed by replacing the soil of the ground and the solidified filler Diagram showing conventional technology

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground 2 Drilling hole 3 Solidification filler 4 Cast-in-place pile (pile)
51 Outer bit 52 Casing pipe 61 Inner bit 62 Inner rod 7 Injection pipe

Claims (5)

A cast-in-place pile construction method in which a solidified filler is placed in an excavation hole formed in the ground, and a pile is constructed in the ground at the site,
The casing pipe is discarded while forming the excavation hole in a substantially vertical direction in the ground by a cylindrical casing pipe having an outer bit at its tip and drilling water supplied to the inside of the casing pipe. Is inserted into the ground,
After forming the excavation hole, a predetermined amount of the solidified filler is injected into the casing pipe from the injection pipe inserted into the casing pipe, and then the casing is substantially the same as the section into which the solidified filler is injected. Pull out the pipe
A method for constructing cast-in-place piles, wherein the soil in the ground and the solidified filler are replaced.   2. The cast-in-place pile construction method according to claim 1, wherein the ground is excavated while a rotational force and a striking force are applied to the casing pipe. A cast-in-place pile construction method in which a solidified filler is placed in an excavation hole formed in the ground, and a pile is constructed in the ground at the site,
A cylindrical casing pipe having an outer bit at its tip, an inner rod having an inner bit inserted into the tip of the casing pipe at its tip, and drilling water supplied into the inner rod While expelling soil while forming the excavation hole in a substantially perpendicular direction to the ground, the casing pipe is inserted into the ground,
After forming the excavation hole, the inner rod is pulled out from the casing pipe with the casing pipe remaining in the excavation hole.
After injecting a predetermined amount of the solidified filler from the injection pipe inserted into the casing pipe into the casing pipe, the casing pipe is pulled out only in a section substantially the same as the section in which the solidified filler is injected,
A method for constructing cast-in-place piles, wherein the soil in the ground and the solidified filler are replaced.   4. The cast-in-place pile construction method according to claim 3, wherein the ground is excavated while applying a rotational force and a striking force to the casing pipe and the inner rod.   5. The cast-in-place pile construction method according to claim 1, wherein the cast-in-place pile has a diameter of 300 mm or less.

Images