JP2008008077A - Expanded root forming method in all casing construction method, and expansion drilling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable recovery of almost all of drilled earth and sand from an expansion drilled hole. <P>SOLUTION: According to an expanded root forming method in an all casing construction method, a casing is pressed into the underground to be at a given depth by discharging earth and sand out of the casing while pressing in the casing. The casing is then pulled up by a necessary length, leaving behind a continuous shaft consisting of an upper shaft, where the peripheral ground is drilled in expansion, and a lower shaft which is continuous with the upper shaft under it to serve as an earth and sand accumulating hole. The peripheral ground of the upper shaft is then drilled in expansion by the rotation and drop of an expansion drilling member, during which expansion drilled earth and sand accumulating on the bottom of an expansion drilled hole is scraped together by the rotating expansion drilling member to drop the scraped earth and sand into the central earth and sand accumulating hole for recovery. Afterward, concrete is placed by striking in the casing, the expansion drilled hole, and the earth and sand accumulating hole. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, a casing having excavation claws at the lower end is rotated by an all-around swivel press-fitting device installed on the ground to press-fit into the ground, and after the earth and sand inside the casing is discharged, concrete is poured into the casing. The present invention relates to an enlarged root forming method for simultaneously forming an enlarged root at the lower end portion of the pile and an enlarged excavation device used in the all casing construction method for constructing a cast-in-place pile.

  Conventionally, as an enlarged root construction method in this type of all-casing construction method, a drilling bucket formed on an expanding door with an excavating blade that can expand a part of the peripheral wall of a cylindrical bucket outward is used, and the casing is rotated. While being press-fitted into the ground, the drilling bucket is rotated by a kelly bar and inserted into the casing to excavate and discharge the soil in the casing, and when the casing is press-fitted to a predetermined depth, the drilling bucket is moved downward from the lower end of the casing. The above expansion door is opened outward from the outer diameter of the casing in a state of projecting to the outside, and the ground below the casing is expanded and excavated by this open expansion door, and the expanded excavated soil is scraped into the bucket by the expansion door. Then, after closing the expansion door and lifting the drilling bucket, after placing concrete in the casing and the expansion hole Pull the pacing, thereby method of construction the place pile having an enlarged root to the lower end is known. (Patent Document 1)

  In addition, a casing formed with an expanding blade with an excavating blade that can be expanded to the outside at a part of the peripheral wall at the lower end of the casing is used. After excavating the soil and press-fitting the casing to a predetermined depth, open the expansion wing outward to expand the ground around the lower end of the casing and scrape the expanded excavated soil into the casing with the expansion wing. It is also known that soil is removed again with a hammer grab, and then the spreader blade is closed, and then the casing is pulled out and concrete is placed (Patent Document 2).

  However, the former has the inconvenience of separately requiring a large Kelly bar type rotary drive to rotate the drilling bucket, and the latter significantly reduces the strength of the lower end of the casing and causes the casing to rotate and press into the hard ground. In addition, there was a case where each part was deformed or damaged during the expansion excavation of the expansion blade, and the desired expansion excavation hole could not be obtained.

  In order to improve this, an excavation bucket is inserted into the casing through a spline so as to be able to transmit rotation, and an enlarged arm having an excavation blade at the tip is supported in the bucket so as to be movable forward and backward in a radial direction from the bucket peripheral wall. Using a drilling bucket in which a hydraulic cylinder for advancing and retreating the expansion arm is mounted in the bucket, and as another example, a plurality of friction grips that can transmit rotation by being in pressure contact with the inner peripheral surface of the casing on the upper outer peripheral surface of the bucket A plate is provided so as to be able to advance and retreat, a part of the peripheral wall of the bucket is formed as an expanding blade that can be expanded outward, and a hydraulic cylinder that expands and contracts the expanding blade is used in the bucket, and a casing is used. Rotate and press-fit into the ground while excavating and discharging the sand in the casing with the excavation bucket, and press-fitting the casing to a predetermined depth, The expansion arm or expansion wing is pushed outward to perform expansion excavation, and the expanded excavation soil is scraped into the bucket by the expansion arm or expansion blade, then the expansion arm or expansion blade is closed and the excavation bucket is lifted, and then inside the casing And what casts concrete in an expanded excavation hole was proposed (patent document 3).

  However, in the above proposed method, the hydraulic cylinder that opens and closes the expansion arm or the expansion wing is installed in the excavation bucket. Often, driving back and forth becomes impossible.

Furthermore, in any of the above conventional examples, the bottom surface of the enlarged excavation hole and the inner bottom surface of the bucket or the like are substantially at the same height, so that the sediment accumulated on the bottom surface of the enlarged excavation hole is rotated by the expansion door, the expansion blade, etc. When scraping into a bucket, etc., the scraped soil accumulates near the scraping opening in the bucket, which tends to prevent the subsequent sediment from being introduced into the bucket. It remained, and this caused inconveniences such as weakening the bond between the enlarged root and the original ground during concrete placement, and lowering the quality of the enlarged root.
JP-A-10-184257 JP-A-9-228769 JP-A-2005-61205

  In the all-casing method, the first invention of the present application is capable of collecting most of the excavated sediment at a predetermined position even when a small amount of excavated sediment is left when scraping off unfavorable excavated sediment by the rotation of the expanded excavation member. It is an object to provide an expanded root creation method.

  It is an object of the second invention of the present application to provide an enlarged excavator capable of effectively carrying out the enlarged root forming method of the first invention.

  The third invention of the present application is to provide an expansion excavation apparatus capable of sufficiently collecting excavation earth and sand remaining on the bottom surface of the expansion excavation hole in the first invention.

  It is an object of the fourth invention of the present application to provide an enlarged excavator provided with a simple measuring device capable of measuring the depth position of the enlarged excavator.

As means for solving the above problems, the first invention of the present application is:
While press-fitting the casing, the earth and sand in the casing is discharged and pressed into the ground to a predetermined depth,
Next, the casing is lifted to the required length, and after the lifting, the upper vertical hole to be expanded and excavated in the surrounding ground, and the continuous vertical hole to be the bottom vertical hole to be a sediment reservoir hole are left below. ,
Next, the ground around the upper vertical hole is expanded by rotating and lowering the expanded excavation member, and the expanded excavated sediment deposited on the bottom surface of the expanded excavation hole is collected by the rotating expanded excavation member and placed in the central sediment reservoir hole. Dropped into
After the expansion excavation is completed, the expansion excavation member is pulled up, and the excavation sediment in the sediment reservoir hole is discharged,
Next, the concrete is placed in the casing, the enlarged excavation hole and the sediment storage hole.
We propose an expanded root construction method in the all-casing method.

The second invention of the present application is
A plurality of friction grip plates that are to be pressed against the inner peripheral surface of the casing are supported on the outer peripheral surface of the cylindrical body so as to be capable of moving forward and backward in the radial direction at equal angular intervals. Equipped with a fluid pressure cylinder that advances and retracts
Multiple enlarged excavating arms with at least a drilling bit projecting from the lower surface of the body at the tip can be extended outward from the casing outer diameter and inward from the casing inner diameter at equal angular intervals. Support each reversibly,
A fluid pressure cylinder for advancing and retreating the expansion excavation arm is provided, and the fluid pressure cylinder is covered with a cover in order to cut off the surrounding excavation earth and sand.
Proposing an extended drilling rig,

The third invention of the present application is
The earth and sand guide blade located on the rear side of the rotating enlarged excavating arm is attached to the enlarged excavating arm in the second invention,
The earth and sand guide blade is in contact with the bottom surface of the enlarged excavation hole when the enlarged excavation arm is advanced, and the blade outer surface is positioned near the rotation trajectory of the enlarged excavation arm tip so that the blade surface rotates Facing diagonally,
Propose an extended drilling rig.

The fourth invention of the present application is
In order to supply and discharge pressure fluid to and from each of the fluid pressure cylinders of the friction grip plate and the expansion excavation arm in the second or third aspect of the invention, a fluid having one end connected to the ground hydraulic device and the other connected to the expansion excavation device The expansion excavation apparatus in any one of Claim 2 and 3 provided with the depth measurement apparatus of the expansion excavation apparatus which arrange | positions the measuring device which detects the feeding length of this hose in the appropriate position of a pressure hose.

  According to the enlarged root formation method in the all casing method of the first invention of the present application, the bottom surface of the central sediment reservoir hole is located lower than the bottom surface of the expanded excavation hole in the expanded excavation by the rotating expanded excavation member. The excavated sediment accumulated on the top is scraped off by an enlarged excavating member and dropped into the central sediment reservoir hole, and the fallen sediment does not interfere with the fall of the subsequent sediment into the reservoir hole. Even if a small amount of earth and sand is deposited on the soil, it can be collected almost in the reservoir hole, and a high-quality expanded root can be created.

  According to the enlarged excavator of the second invention of the present application, the enlarged root forming method of the first invention can be effectively implemented, and in particular, the excavating bucket and casing are equipped with the enlarged excavating blade as in the conventional apparatus. Unlike the conventional one, it is configured as a dedicated machine for expansion excavation, so that it can reliably perform the expected expansion excavation and reduce the risk of sand clogging in the fluid pressure cylinder that advances and retracts the expansion excavation arm. it can.

  According to the expansion excavation apparatus of the third invention of the present application, the excavation earth and sand accumulated on the bottom surface of the expansion excavation hole can be sufficiently gathered by the expansion excavation arm and the earth and sand guide blade and can be put into the central vertical hole. .

  According to the expansion excavation apparatus of the fourth invention of the present application, the expansion excavation for exposing the expansion excavation arm from the lower end of the casing by a simple device provided with a measuring device for detecting the feeding length of the hose at an appropriate position of the fluid pressure hose. By confirming the descent distance of the device, the descent distance of the enlarged excavation arm from the start to the end of the enlarged excavation, etc., it is possible to create the enlarged root as designed.

For convenience of the enlarged excavator , first, an embodiment of the enlarged excavator of the second invention will be described with reference to the drawings.
In FIG. 1, an enlarged excavator (1) suspended by a crane wire (W) is inserted into a casing (C) so as to be movable up and down, and the enlarged excavator (1) has a cylindrical body (2). In addition, four rectangular holes (3) that open to the outer peripheral surface are opened radially at equal angular intervals, and hydraulic cylinders (4) are installed at the bottom of each hole (3), and each cylinder The friction grip plate (5) is fixed to the piston rod tip of (4), and the casing is moved forward and backward by the cylinder (4) to move the friction grip plate (5) forward and backward from the outer peripheral surface of the body (2). (C) The inner peripheral surface can be contacted and separated, and two enlarged excavation arms (6) and (6) having excavation bits are attached to the lower surface of the body (2).

  The enlarged excavating arms (6) and (6) slide the outer cylinder (8) having a excavating bit (9). The outer cylinder (7), (8) is used as an expansion / contraction cover, a hydraulic cylinder (10) is housed in the cover, and the base end of the cylinder (10) is the inner cylinder. While fixing to the closed end of (7), the front-end | tip of piston rod (11) is being fixed to the closed end of an outer cylinder (8).

  The mounting structure of the enlarged excavation arms (6) and (6) is as follows. A support plate (13) as shown in FIG. 4 is vertically projected on the diameter line on the bottom surface of the bottom plate (12) of the body (2), and the inner cylinder (7) is formed on both side surfaces of the support plate (13). The stay bars (14) and (14) having a length that is approximately one half of the length of the inner cylinders (7) and (7) are fixed horizontally to the side surfaces of the stay bars (14) and (14). ) Are fixed horizontally with the open ends of the inner cylinders facing each other in the opposite direction, whereby the inner cylinders (7), (7) are spaced apart from the support plate (13). Fixed respectively.

  On the other hand, as shown in FIG. 3, the outer cylinders (8) and (8) have a groove (15) cut from the open end to almost the middle on one side wall, and this outer cylinder (8) , (8) are fitted into the inner cylinders (7), (7), and (15), (15) are engaged with the stay bars (14), (14), respectively, so that they can expand and contract. .

  The expansion excavation arms (6) and (6) include an earth and sand guide blade for guiding the expansion excavation earth and sand by the excavation bits (9) and (9) of the arms (6) and (6) to the center gawa ( 16) and (16). 2 and 3, the base end of the arm (17) is fixed to the outer surface of the rear end of the outer cylinders (8) and (8), and the tip of the arm (17) is A cylinder (8) is extended to a side opposite to the rotation direction of the excavation bit (9)... Of the excavation bit (9)... And a blade (16) having a wide vertical width is appropriately fixed to the extension end.

  The blades (16) and (16) have their outer tips projected to the vicinity of the rotation trajectory of the excavation bit (9) at the tip of the outer cylinder (8). The blade (16) is directed obliquely with respect to the rotation direction of the cylinder (8), and the lower side of the blade (16) is at the same height as the excavation bits (9) at the bottom of the tip of the outer cylinder (8) as shown in FIG.

  (18) and (18) are skirts surrounding the enlarged excavation arms (6) and (6), and have the outer cylinders (8) and (8) and the entrances and exits of the earth and sand guide blades (16) and (16).

  When the expansion excavator (1) is inserted into the casing (C), a support table (19) is detachably mounted on the upper end of the casing (C), and a swivel bearing ( 20), a bracket (21) is installed, and guide pulleys (23) and (23) for guiding the hydraulic hoses (22) and (22) are pivotally supported on the bracket (21).

  One end of each of the hydraulic hoses (22) and (22) is connected to a hydraulic device installed on the ground, and the other end is connected to a rotary block (24) at the upper end of the enlarged excavator (1) together with a crane wire (W). Then, the hydraulic hoses (22), (22) are connected from the rotating block (24) through the swivel joint (25) to the hydraulic cylinder (4) of the friction grip plate and the hydraulic cylinder (10) of the enlarged excavating arm. It is connected via a hydraulic pressure supply path.

  As an example, as a measuring instrument for detecting the depth position in the casing (C) of the expansion excavator (1), a rotary encoder (26) is used as shown in FIG. 1, and a hydraulic hose guide pulley (23), ( 23), and the depth position of the enlarged excavator (1) is detected by detecting the feed length of the hydraulic hoses (22), (22).

Example of enlarged root reclamation method using the expanded drilling device on enlarged root Construction Method Example (1) will be described.
An all-around swivel press-fitting machine (R) installed on the ground grips a casing (C) with an excavation claw at its lower end, and intermittently in the ground for a fixed length while swiveling the casing (C). As shown in FIG. 5 (a), the hammer grab (G) is suspended by the crane wire (W) and inserted into the casing (C), and the sediment in the casing is excavated. Excavate. When this press-fitting and soiling are repeated to press-fit the casing (C) to a predetermined depth, the hammer grab (G) is pulled up.

Next, the casing (C) is pulled up to the required length by driving the all-around swivel device (R) as shown in FIG. 5 (B), and the lifting position is provided with a planned enlarged excavation hole (E) indicated by a dotted line in the surrounding ground. It is an upper end of a continuous vertical hole with a power upper vertical hole (P ₁ ) and a lower vertical hole (P ₂ ) to be a sediment accumulation hole (S) continuously below it. The enlarged drilling hole planned in this example has a truncated cone shape.

  Next, the expansion excavator (1) suspended by the crane wire (W) is inserted into the casing (C), and a support table (19) with a bracket (21) is attached to the upper end of the casing (C). The hydraulic hoses (22) and (22) are hung on the guide pulleys (23) and (23) supported by

  Here, the crane wire (W) and the hydraulic hoses (22), (22) are fed out to lower the enlarged excavator (1) into the casing (C), and the enlarged excavating arms (6), (6) are the casing. (C) Stop descent at a position exposed downward from the lower end. In this case, if the total length of the casing (C) and the distance from the pulley (22) to the enlarged excavation arm (6) are measured in advance, the feeding length of the hydraulic hose (22) displayed on the rotary encoder (26) is set. It is possible to accurately determine the descending position of the enlarged excavating arm (6) by detecting.

  After the descent stop, the pressure oil is sent to each hydraulic cylinder (4) through the hydraulic hose (22) and driven to advance, and the friction grip plates (5) are pressed against the inner peripheral surface of the casing (C). Then, the entire expansion excavator (1) is fixed to the casing (C), and the casing (C) is rotated and moved up and down and driven.

  Next, the casing (C) is rotated by driving the all-around swivel press-fitting device (R), and the rotation is transmitted to the enlarged excavator (1) through the friction grip plates (5). 22), pressure oil is sent to the hydraulic cylinders (10) and (10) in small amounts to gradually advance the expanded excavating arms (6) and (6), and at the same time, by driving the press-fitting device (R). The casing (C) is gradually press-fitted, thereby starting a truncated conical expansion excavating downward as shown in FIG.

  In the above-mentioned expansion excavation, the expansion excavation earth and sand accumulates on the bottom surface (Eb) of the expansion excavation hole (Ea), and the central sedimentation hole is collected by collecting the outer cylinders (8) and (8) of the expansion excavation arm that rotates. Although it falls in (S), the earth and sand which cannot be scraped off remain a little on the bottom face (Eb). These residual earth and sand are collected by the earth and sand guide blades (16) and (16) and dropped into the reservoir hole (S).

  In the above earth and sand scraping, the earth and sand scraped off on the bottom surface (Eb) is scraped into a reservoir hole (S) lower than the bottom surface (Eb). There is no hindrance to the fall.

  When the planned expansion excavation is completed as shown in FIG. 6 (d), the expansion excavation arms (6), (6) are reduced by the backward drive of the hydraulic cylinders (10), (10), and then the hydraulic cylinders (4) ... , The friction grip plate (5) is retracted from the pressure contact with the inner peripheral surface of the casing (C), the support table (19) is removed from the upper end of the casing (C), and in this state, the crane wire (W) The enlarged excavator (1) is pulled upward through the casing (C).

Completion of the scheduled expansion excavation by the expansion excavator (1) is when the press-fit and drop length of the casing (C) from the start of the expansion excavation coincides with the length of the vertical hole (P ₁ ) in FIG. It is.

  After the expansion excavator (1) is lifted, the hammer grab (G) is again passed through the casing (C) and lowered into the sediment reservoir hole (S), and the expanded excavation collected in the reservoir hole (S) Scrap and remove earth and sand.

  Next, as shown in the figure (e), a reinforcing steel basket is inserted into the casing (C) from which excavated earth and sand have been removed and into the earth and sand reservoir hole (S), and concrete (T) is placed through the tremy pipe. .

  If the casing (C) is pulled out before the concrete is hardened, a concrete pile (P) having an enlarged root (D) at the lower end is constructed as shown in FIG.

It is a partially-omission longitudinal front view of the state which inserted the expansion excavator in the casing. It is the sectional view on the AA line of FIG. 1 of the state which expanded the expansion excavation arm. It is a slope view of an outer cylinder. FIG. 3 is a sectional view taken along line B-B in FIG. 2. (A) It is a general | schematic longitudinal cross-sectional view of the casing rotation press injection process in the expansion root construction method by an all casing construction method. (B) It is an approximate line longitudinal cross-sectional view of the state where expansion excavation preparation is completed. (C) It is an approximate line longitudinal cross-sectional view of an expansion excavation process. (D) It is an approximate line longitudinal cross-sectional view of an expansion completion state. (E) It is an approximate line longitudinal cross-sectional view of a concrete placement process. (F) It is an approximate line longitudinal cross-sectional view of a concrete pile construction state with an enlarged root.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Expanding excavator 2 Body 4 Hydraulic cylinder 5 Friction grip board 6 Expanding excavating arm 7 Inner cylinder 8 Outer cylinder 9 Drilling bit 10 Hydraulic cylinder 16 Sediment guide braid P ₁ Upper vertical hole P ₂ Lower vertical hole S Sediment reservoir hole C Casing Ea Expanded drilling hole Eb Expanded drilling hole bottom D Expanded root P Concrete pile

Claims (4)

While press-fitting the casing, the earth and sand in the casing is discharged and pressed into the ground to a predetermined depth,
Next, the casing is lifted to the required length, and after the lifting, the upper vertical hole to be expanded and excavated in the surrounding ground, and the continuous vertical hole to be the bottom vertical hole to be a sediment reservoir hole are left below. ,
Next, the ground around the upper vertical hole is expanded by rotating and lowering the expanded excavation member, and the expanded excavated sediment deposited on the bottom surface of the expanded excavation hole is collected by the rotating expanded excavation member in the central sediment reservoir hole. Dropped into
After the expansion excavation is completed, the expansion excavation member is pulled up, and the excavation sediment in the sediment reservoir hole is discharged,
Next, the concrete is placed in the casing, the enlarged excavation hole and the sediment storage hole.
Expanded root creation method in the all casing method. A plurality of friction grip plates that are to be pressed against the inner peripheral surface of the casing are supported on the outer peripheral surface of the cylindrical body so as to be capable of moving forward and backward in the radial direction at equal angular intervals. Equipped with a fluid pressure cylinder that advances and retracts
Multiple enlarged excavating arms with at least a drilling bit projecting from the lower surface of the body at the tip can be extended outward from the casing outer diameter and inward from the casing inner diameter at equal angular intervals. Support each reversibly,
A fluid pressure cylinder for advancing and retreating the expansion excavation arm is provided, and the fluid pressure cylinder is covered with a cover in order to cut off the surrounding excavation earth and sand.
Expansion drilling rig. The earth and sand guide blade located on the rear side of the rotating expansion excavation arm is attached to the expansion excavation arm,
The earth and sand guide blade is in contact with the bottom surface of the enlarged excavation hole when the enlarged excavation arm is advanced, and the blade outer surface is positioned near the rotation trajectory of the enlarged excavation arm tip so that the blade surface rotates Facing diagonally,
The expansion excavator according to claim 2. In order to supply and discharge pressure fluid to and from the fluid pressure cylinders of the friction grip plate and the expansion excavation arm, the hose is placed at a proper position of a fluid pressure hose connected at one end to the ground hydraulic device and at the other end to the expansion excavation device. The expansion excavation apparatus in any one of Claim 2 and 3 provided with the depth measurement apparatus of the expansion excavation apparatus which arrange | positions the measuring device which detects the feeding length of this.

Images