JP2006299595A - Auger excavation head for forming bulb in pile installation by inner excavation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an auger excavation head for forming a bulb in pile installation by inner excavation for extremely enlarging an inner diameter of an excavation hole, for forming an expanded bulb having an extremely large diameter on the tip of a pile. <P>SOLUTION: A structure of the auger excavation head for forming the bulb in the pile installation by inner excavation, is constituted by arranging an injection nozzle 6 on the tip of an inner cylinder 5, by connecting an injection cylinder 1 and a hollow rod 8 by a pipe 9, by installing and fixing the injection cylinder 1 for extensively storing the inner cylinders 4a, 4b and 5 in and to a fixed outer cylinder 3 along a blade 2 spirally installed on the outer periphery of the hollow rod 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a structure of a drilling head used in a medium excavation method in which a screw auger having a drilling head is pushed through a ready-made hollow pile, and the ready-made hollow pile is built into the ground by rotation of the screw auger. In particular, the present invention relates to a structure of an excavation head that is used to construct an enlarged bulb at the lower end of the hollow pile after the hollow pile has been built to a predetermined depth.

  As a conventional well-known technique related to the structure of an excavation head used to construct an enlarged bulb at the lower end of the hollow pile after the hollow pile is built to a predetermined depth as in the present invention, Japanese Patent Application Laid-Open No. 2004-183377 Japanese Laid-Open Patent Publication No. 2004-324274 (Patent Document 2) is known.

  These techniques of Patent Documents 1 and 2 both pass a fluid guide path through which a high-pressure fluid should be guided from the outside into a hollow rod of an auger excavation head having a drilling blade at the tip, and jet the high-pressure fluid to the tip. An injection nozzle capable of performing the above-described configuration is mounted and configured to extend and contract in a radial direction on a radial extension line among a plurality of extendable injection cylinders attached to the outer peripheral surface of the hollow rod. And it is the technique which can further dig the hole wall of an excavation hole, and can form the enlarged hole for enlarged bulbs with a large diameter by ejecting a high pressure fluid, extending the said injection nozzle.

JP 2004-183377 A JP 2004-324274 A

  The conventional techniques as shown in the above-mentioned Patent Document 1 and Patent Document 2 are configured such that a high-pressure fluid can be ejected from an injection nozzle that can be expanded and contracted on the outer peripheral surface of the hollow rod. Therefore, it is possible to further drill the hole wall of the drilling hole to form an enlarged hole having a certain diameter by extending the injection nozzle and ejecting the high-pressure fluid. For the reason, it has been extremely difficult to form an enlarged hole with a large diameter required to construct an enlarged bulb for maximizing the bearing capacity of the pile body.

  That is, in the techniques described in Patent Document 1 and Patent Document 2, a telescopic injection cylinder is attached to the outer peripheral surface of the hollow rod, and the injection nozzle can be expanded and contracted on the radial extension line in the injection cylinder. However, since the tip of the injection cylinder cannot protrude beyond the outer diameter of the excavating blade of the excavation head, the length of the injection cylinder is limited. There is a problem that even if a higher pressure fluid is ejected, an enlarged hole having a desired large diameter cannot be excavated.

  An auger excavation head for bulb formation in an intermediate excavation method according to the present invention is a completely new technology developed in view of the above-described conventional technology, and in particular, a plurality of telescopic augers having a high-pressure fluid injection nozzle at the tip. In the medium digging method in which an injection cylinder having a large axial length can be used by attaching the injection cylinder along the blade of the excavation head, thereby enabling to drill an enlarged hole having a larger diameter. The technology of an auger excavation head for bulb formation is provided.

  The bulb-forming auger excavation head in the intermediate excavation method according to the present invention is an invention that fundamentally improves the above-mentioned conventional problems, and the first configuration is that a spiral blade is projected on the outer peripheral surface. A central pipe of the hollow rod provided is provided with a flow path for introducing a high-pressure fluid from the outside, and a plurality of extendable and axially long injection cylinders having a high-pressure fluid injection nozzle at the tip are attached along the blade, and the pipe is attached. In the middle digging method, the rear part of the injection cylinder and the flow path of the hollow rod are connected to each other, and the injection cylinder can be expanded and contracted by the pressure of the high pressure fluid pumped from the outside to the flow path of the hollow rod. This is an auger drilling head for forming a bulb.

  According to a second configuration of the bulb forming auger excavation head in the intermediate digging method of the present invention, the injection cylinder includes a fixed outer cylinder and an inner cylinder accommodated in the fixed outer cylinder. 2. The bulb forming auger excavating head according to claim 1, wherein the auger excavating head is adapted to move forward or backward by a predetermined distance by the pressure of a high-pressure fluid introduced into the injection cylinder or by a spring stored in the injection cylinder. is there.

  Further, a third configuration of the bulb forming auger excavation head in the intermediate excavation method of the present invention is characterized in that the tip end portion of the injection cylinder is inclined downward at substantially the same angle as the blade. The bulb forming auger excavation head having the first configuration or the second configuration.

  According to a fourth configuration of the bulb forming auger excavation head in the intermediate digging method of the present invention, the excavation blade is provided at the tip of the injection nozzle of the injection cylinder at a predetermined distance from the injection nozzle via a bracket. A bulb-forming auger excavation head having a first configuration to a third configuration, which is provided.

  Further, a fifth configuration of the auger excavation head for bulb formation in the intermediate excavation method of the present invention is such that the excavation blade is inclined in a predetermined direction, and the high-pressure fluid injected from the tip of the injection nozzle strikes the excavation blade. Thus, a bulb forming auger excavation head having a fourth configuration is characterized in that it is configured to be ejected in the direction in which the excavation blade advances.

  In the first configuration of the bulb-forming auger excavation head in the above-described medium excavation method according to the present invention, since a plurality of telescopic injection cylinders are attached along the blade, the injection with a large axial length is performed. A tube can be attached around the hollow rod. Therefore, the stroke of the injection cylinder can be increased, and the injection nozzle at the tip thereof can be greatly extended outward.

  Since the rear part of the injection cylinder and the flow path of the hollow rod communicate with each other via a pipe, the injection cylinder is made to have a predetermined length by using the pressure of the high-pressure fluid pumped from the outside to the flow path of the hollow rod. Can be stretched.

  Further, in the second configuration of the bulb forming auger excavation head in the intermediate digging method according to the present invention, the injection cylinder is constituted by a fixed outer cylinder and an inner cylinder accommodated in the fixed outer cylinder. In addition, since the inner cylinder is configured to move forward or backward by the pressure of a high-pressure fluid or a spring, the expansion and contraction of the injection cylinder can be easily operated from the ground.

  Further, in the third configuration of the bulb forming auger excavation head in the medium excavation method according to the present invention, the injection cylinder attached along the blade is inclined downward at substantially the same angle as the blade. Therefore, the high-pressure fluid can be ejected from the ejection cylinder toward the excavation direction of the excavation head.

  In the fourth configuration of the bulb forming auger excavation head in the intermediate digging method according to the present invention, the bracket is attached to the tip of the injection nozzle of the injection cylinder at a predetermined distance from the injection nozzle. Since the excavating blade is attached, when the injection nozzle of the injection cylinder is extended, the inner wall of the excavation hole can be excavated by the excavation blade.

  Further, in the fifth configuration of the bulb forming auger excavation head in the medium excavation method according to the present invention, the excavation blade in the fourth configuration is inclined in a predetermined direction, so that the tip of the injection nozzle Since the high-pressure fluid injected from the nozzle can hit the excavating blade and eject it in the direction of advancement of the excavating blade, an effect of lowering the resistance of earth and sand acting on the excavating blade can be expected.

  An embodiment of the bulb forming auger excavation head in the medium digging method according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows the essential features of the bulb forming auger digging head in the medium digging method according to the present invention. FIG. 2 is a plan view in which a part of FIG. 1 is omitted, FIG. 3 is a longitudinal sectional view of the injection cylinder of FIG. 1, and FIG. 4 shows the relationship between the injection cylinder and blades of FIG. FIG.

  1 to 4, reference numeral 1 denotes an injection cylinder having an axial length that can be placed and fixed along the upper surface of a blade 2 that is attached to the outer periphery of a hollow rod 8 described later in a spiral manner. is doing. The injection cylinder 1 is composed of a fixed outer cylinder 3 and two inner cylinders 4a, 4b, 5 housed therein. An injection nozzle 6 is provided at the tip of the inner cylinder 5.

  A coil spring 7 is attached to the rear end of the inner cylinder 5, and the inner cylinder 5 is connected to the rear end of the fixed outer cylinder 3 via the coil spring 7. The rear end of the fixed outer cylinder 3 and the hollow rod 8 are connected by a pipe 9, and the flow path of the central tube of the hollow rod 8 communicates with the hollow portion in the fixed outer cylinder 3. Therefore, the high pressure fluid pumped from the outside to the flow path of the hollow rod 8 is pumped to the fixed outer cylinder 3, and the inner cylinders 4, 5 can be expanded and contracted by the pressure of the high pressure fluid and the action of the coil spring 7. is doing. The coil spring 7 can be replaced with an air damper.

  As shown in FIG. 1, the excavation blade 10 is attached to the tip of the inner cylinder 5 via a bracket (not shown) at a predetermined interval. Therefore, when the inner cylinder 5 (injection nozzle 6) is extended, the outer wall of the excavation hole can be excavated with the excavation blade 10 to increase the inner diameter of the excavation hole.

  Further, as shown in FIG. 1, the excavation blade 10 is inclined in a predetermined direction, and the high-pressure fluid 11 ejected from the injection nozzle 6 is applied to the excavation blade 10 and ejected in the advancing direction of the excavation blade 10. It is configured to be able to.

  In the present invention, since the injection cylinder 1 is placed and fixed along the upper surface of the blade 2 as described above, the injection cylinder attached to the conventional hollow rod so as to expand and contract radially on the radial extension line. Unlike the above, the axial length of the injection cylinder 1 can be made extremely large.

  Therefore, the stroke of the injection cylinder 1 composed of the fixed outer cylinder 3 and the inner cylinders 4a, 4b, and 5 is increased so that the injection nozzle 6 can be greatly extended outward, thereby reducing the inner diameter of the drilling hole. It is configured to be able to excavate significantly.

  For example, when the excavation head of the present invention is used, assuming that the diameter of the hollow rod 8 is 154 mm and the outer diameter of the blade 2 is 380 mm, the axial length of the fixed outer cylinder 3 of the injection cylinder 1 is 261 mm, In addition, when the inner cylinders 4a, 4b, and 5 are extended, the injection nozzle 6 can be protruded by 230 mm from the tip of the fixed outer cylinder 3, thereby having an inner diameter of 820 mm. Drilling holes can be formed.

  Further, when the injection cylinder 1 is mounted on the upper surface of the blade 2 and fixed, the injection cylinder 1 can be inclined by about 35 °. Therefore, the high-pressure fluid 11 can be ejected downward from the injection nozzle 6, that is, in the excavation direction, and the excavation head can be smoothly excavated.

  In the above-described embodiment, the injection cylinder 1 is mounted and fixed on the upper surface of the blade 2, but the injection cylinder 1 can be attached and fixed to the lower surface of the blade 2. Since the excavated soil is discharged along the upper surface of the blade, it is more reasonable to attach the injection cylinder 1 to the lower surface of the blade 2 without disturbing the soil removal.

  The expansion and contraction of the injection cylinder 1 can be performed by supplying a high-pressure fluid 11 into the fixed outer cylinder 3 of the injection cylinder 1. By first supplying the high pressure fluid 11 of about 5 MPa, then about 10 MPa, and about 15 to 20 MPa, the inner cylinders 4 a, 4 b, and 5 are gradually projected from the fixed outer cylinder 3 to extend the injection nozzle 6 to the maximum extent. I can do it. After the excavation of the excavation hole is completed, by reducing the injection pressure, the inner cylinders 4a, 4b, and 5 can be accommodated in the fixed outer cylinder 3 by the action of the coil spring 7, and the injection cylinder 1 can be contracted.

  After completion of the excavation of the excavation hole, cement milk is injected from the injection nozzle 6 into the enlargement excavation part of the excavation hole through the hollow rod 8 and the injection cylinder 1, thereby solidifying this and creating an enlarged bulb However, the support capacity of the pile can be increased by the enlarged bulb.

  This case describes the method of building an enlarged bulb at the tip of a pile that is constructed by the medium excavation method, but it can also be applied to the case of construction by the pre-boring method. Rather, the pre-boring method can be easily applied to the extent that it is not necessary to house the excavator in the pile hollow portion than the case of the intermediate excavation method.

It is explanatory drawing which shows the structure of the principal part of the auger excavation head for bulb | ball formation in the inside digging method which concerns on this invention. It is the top view which abbreviate | omitted a part of FIG. It is a longitudinal cross-sectional view of the injection cylinder of FIG. FIG. 2 is a perspective explanatory view showing a relationship between an injection cylinder and a blade in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Injection cylinder 2 ... Blade 3 ... Fixed outer cylinder 4a ... Inner cylinder 4b ... Inner cylinder 5 ... Inner cylinder 6 ... Injection nozzle 7 ... Coil spring 8 ..Hollow rod 9 ... Pipe 10 ... Excavating blade 11 ... High pressure fluid

Claims (5)

  A central tube of a hollow rod projecting a spiral blade on the outer peripheral surface is provided with a flow path for introducing a high-pressure fluid from the outside, and a plurality of telescopic and long-cylinder injection cylinders having a high-pressure fluid injection nozzle at the tip are provided. Attached along the blade, the rear part of the injection cylinder and the flow path of the hollow rod are connected to each other via a pipe, and the injection cylinder is expanded and contracted by the pressure of the high-pressure fluid pumped from the outside to the flow path of the hollow rod. The auger drilling head for bulb formation in the medium digging method made possible.   The injection cylinder is composed of a fixed outer cylinder and an inner cylinder accommodated in the fixed outer cylinder, and the inner cylinder is advanced a certain distance by the pressure of high-pressure fluid introduced into the injection cylinder or a spring stored in the injection cylinder. 2. The bulb forming auger excavation head according to claim 1, wherein the auger excavation head is configured to retreat.   The bulb-forming auger excavation head according to claim 1 or 2, wherein a tip end portion of the injection cylinder is inclined downward at substantially the same angle as the blade.   4. The bulb forming auger excavation head according to claim 1, wherein an excavation blade is provided at a tip portion of the injection nozzle of the injection cylinder via a bracket at a predetermined distance from the injection nozzle. 5. The bulb according to claim 4, wherein the excavating blade is inclined in a predetermined direction so that the high-pressure fluid ejected from the tip of the ejecting nozzle hits the excavating blade and is ejected in the advancing direction of the excavating blade. Auger drilling head for forming.

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