JP2022179972A - Rapid loading test device for pile - Google Patents

Abstract

To provide a rapid loading test device for a pile capable of safely and quickly lifting a weight to its original height.SOLUTION: The present invention comprises a frame 1 erected near a pile head A, a weight lifting jack 5 installed on the frame 1 and used to lift a weight 3 that has fallen on the pile head A to its original height via a weight lifting rod 4, and a weight gripping chuck 7 that vertically suspends the weight 3 from the lower end of the weight lifting rod 4 in a detachable manner. The weight lifting jack 5 comprises a jack body 8 for lifting the weight 3, and an upper chuck 9 and a lower chuck 10 installed respectively on the upper and lower sides of the jack body 8 to hold and release the weight lifting rod 4. When the weight lifting jack 5 lifts the weight 3, the upper chuck 9 grips the weight lifting rod 4 and the lower chuck 10 releases the weight lifting rod 4. The lower chuck 10 grips the weight lifting rod 4 when the upper chuck 9 releases the weight lifting rod 4 and descends with the contraction of the weight lifting jack 8.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rapid loading test device for piles that checks the bearing capacity of the pile from the axial pushing force of the pile acting on the pile head by a weight that drops onto the pile head protruding from the ground surface, and drops onto the pile head. It is designed to allow the weight to be hoisted to its original height very safely and quickly.

A static load test, which is conducted under the same conditions as the actual pile, is widely known as a method for checking the bearing capacity of piles, but this requires the installation of reaction resistance bodies (reaction piles) and load beams. In particular, when a large load is applied, the test becomes a large-scale test, resulting in an increase in the construction period and cost, and there are problems such as the time required for the test.

For this reason, a rapid loading test of piles, in which a weight is dropped onto an actual pile head and an axial pushing force is applied to the pile to confirm the bearing capacity, has attracted attention.

For example, Patent Document 1 includes a weight that drops to the pile head, a catch device that catches the weight that has fallen to the pile head and jumps up, and a lifting device that lifts the weight that has fallen to the pile head to the original height. In particular, jacks, winches, cranes, and the like are used as means for lifting the weight that has fallen on the pile head to its original height.

For example, using a jack to lift a weight that has fallen on a pile head to its original height has hitherto been accomplished by suspending the weight on a threaded rod and extending or retracting the jack that grips the threaded rod. Lift the threaded rod together with the weight for one stroke length of the piston rod, tighten the temporary fixing nut screwed to the male thread of the threaded rod, temporarily fix the threaded rod once, and remove the piston rod. The operation of putting it back, extending or retracting the jack again, and lifting the threaded rod together with the weight was repeated.

Patent No. 6613430 JP-A-2005-68802 Japanese Patent Application Laid-Open No. 2002-303570 Patent No. 6693778

"Super Jack System" 2010/08/06 Social Infrastructure Division JFE Civil Corporation [Searched January 14, 2021] https://www.jfe-civil.com/infra/tokkow/

However, in the conventional method of using a jack to lift the weight that has fallen on the pile head to its original height, the jack used to lift the weight has to be installed on a frame that is framed quite high around the pile head. , The operation of the jack and the work of temporarily fixing the lifting rod on which the weight is suspended are performed manually one by one by the worker on the high trolley, which is extremely inefficient and inefficient work. Met.

In particular, the weight used in the rapid loading test of piles is very heavy, for example, 200 tons. Forced to work inefficiently.

In addition, since the test is performed manually at a high place by workers, not only is it extremely dangerous, but troubles may occur during the work, forcing the suspension of the test.

By the way, there is known a jack-type lifting machine that automatically lifts a load using a lifting jack that has both lifting and lowering functions. , PC steel stranded wires, step bars, etc. are used, and all of them are configured to automatically lift the hoisting member together with the hoisted load by a certain amount using a jack, and finally lift the hoisted load to the desired height. ing.

For example, there is known a technology of a super jack system that makes it possible not only to lift a heavy object, but also to lift a heavy object, which has been considered difficult in the past, by using a jack having both lifting and lowering functions (Non-Patent Document 1).

The super jack system is a jack system that raises or lowers a heavy object by raising or lowering a knotted step rod by expanding or contracting the jack, and is mainly used for dismantling and construction of building structures (patent Reference 4).

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In particular, the technology of the above-mentioned super jack system is used so that a weight that has fallen on the pile head can be lifted up to its original height very safely and quickly. The purpose is to provide a rapid loading test device for piles made into

The present invention is an invention of a rapid loading test apparatus for piles for confirming the bearing capacity of a pile from the axial pushing force acting on the pile head by a weight falling on the pile head that actually protrudes from the ground surface. A frame body erected near the head, a weight lifting jack installed in the frame body for lifting the weight dropped to the pile head to the original height via a weight lifting rod, and the weight lifting The weight-holding chuck includes a weight-holding chuck that is detachably vertically installed at the end of a rod, and a guide device that guides the weight. An upper chuck and a lower chuck are respectively installed on the upper side and the lower side of the main body for gripping and releasing the weight lifting rod, and when the weight lifting jack lifts the weight, the upper chuck lifts the weight. Grasping a lifting rod, the lower chuck releases the weight lifting rod, and when the upper chuck releases the weight lifting rod and descends with the contraction of the weight lifting jack, the lower chuck is It is characterized in that it is configured to grip the weight lifting rod, and in particular, the extension and contraction of the jack body of the weight lifting jack and the gripping and release of the weight lifting rod by the upper chuck and the lower cap are alternately performed. By repeating the above steps, the weight that has fallen on the pile head can be hoisted to its original height very safely and quickly.

In addition, by providing a plurality of joints on the outer periphery of the weight lifting rod at equal intervals in the axial direction of the weight lifting rod, the weight lifting rod is securely held by the upper chuck and the lower chuck, and the pile head is It can safely and reliably lift a weight that has fallen into the ground to its original height.

Furthermore, by providing a weight catching device that catches in the air the weight jumped up by the pile head, it is possible to prevent the weight from rebounding. The chuck can be safely operated by a remote device.

In particular, the present invention is very efficient in lifting a weight dropped to the pile head back to its original height by alternately repeating expansion and contraction of the jack body of the weight lifting jack and gripping and releasing of the weight lifting rod by the upper chuck and the lower cap. and can be lifted quickly.

In addition, by automatically operating the weight lifting jack by remote control, troubles can be minimized and the weight can be hoisted to its original height extremely safely.

1 is a front view showing an embodiment of a rapid loading test apparatus for piles, showing a state in which a weight is suspended from the lower end of a weight lifting rod by a weight chuck. FIG. FIG. 2 is a cross-sectional view of the rapid loading device for piles illustrated in FIG. FIG. 4 is a side view of a weight suspended by a weight chuck from the lower end of a weight lifting rod; It is an enlarged view of a weight lifting jack. FIG. 10 is an explanatory diagram of the operation of the weight lifting jack, and is an enlarged cross-sectional view showing the operation of lifting the weight via the weight lifting rod by the upper chuck gripping the weight lifting rod and the jack body extending. It is an explanatory view of the operation of the weight lifting jack, and is an enlarged cross-sectional view showing the operation of the upper chuck releasing the weight lifting rod and descending along the weight lifting rod due to the contraction of the jack body. It is explanatory drawing of operation|movement of a weight lifting jack, and is an enlarged sectional view which shows the operation|movement which an upper chuck hold|grips a weight lifting rod, and a weight lifting rod descend|falls by shrinking|contracting a jack main body. It is an explanatory view of the operation of the weight lifting jack, and is an enlarged cross-sectional view showing the operation in which the upper chuck releases the weight lifting rod and the jack body extends to rise along the weight lifting rod. It is an exploded perspective view showing an example of a weight chatting device. FIGS. (a) to (c) are longitudinal sectional views showing the operation of the weight chatting device shown in FIG. It is a modification of the weight catching device, FIG. (a) is a longitudinal sectional view, FIG. (b) is a plan view, and FIG. (c) is a longitudinal sectional view for explaining the operation.

1 to 11 illustrate an embodiment of the rapid loading test apparatus for piles of the present invention. The frame 1 of the device is installed.

A frame 2 is installed above the frame 1, a weight lifting rod 4 is vertically installed on the frame 2 toward the pile head A, and the tip of the weight lifting rod 4 is dropped onto the pile head A. A weight 3 is suspended.

A weight lifting jack 5 for lifting the weight 3 to a height at which the weight 3 is dropped is installed on the frame 2 via a weight lifting rod 4 .

The weight 3 is configured by combining a plurality of blocks into one, and is configured such that the overall weight can be adjusted by increasing or decreasing the number of the blocks.

The weight lifting rod 4 is installed vertically through the weight lifting jack 5 on the upper extension of the pile head A, and is supported on the frame 2 by the weight lifting jack 5 so as to be vertically movable.

In addition, joints 6 are formed on the outer periphery of the weight lifting rod 4 at equal intervals in the axial direction of the weight lifting rod 4, and the outer peripheral surface of each joint 6 has a cutting edge that gradually decreases in diameter from the lower end toward the upper end. A truncated conical tapered surface 6a is formed.

Furthermore, a chuck 7 for detachably holding the weight 3 is attached to the lower end of the weight lifting rod 4 , and the weight 3 is held by the chuck 7 so as to be detachably suspended from the lower end of the weight lifting rod 4 . is lowered.

The chuck 7 is configured to detachably hold the weight 3 by operating, for example, hydraulically, and the weight 3 is suspended from the lower end of the weight lifting rod 4 by remote control by radio or wire. , and can be separated from the lower end of the weight lifting rod 4 and dropped onto the pile head A.

The weight lifting jacks 5 are installed on the upper and lower sides of the jack body 8 and the jack body 8 that lifts the weight 3 to the original height from which it was dropped via the weight lifting rod 4 by expanding and contracting in the vertical direction. and comprises an upper chuck 9 and a lower chuck 10 for gripping and releasing the weight lifting rod 4 .

When the piston rod 8a of the jack body 8 is extended to lift the weight 3 via the weight lifting rod 4 (see FIG. 5), the upper chuck 9 grips the weight lifting rod 4 and moves the weight lifting rod. 4 is configured to rise.

When the weight lifting rod 4 descends due to the contraction of the piston rod 8a of the jack body 8 (see FIG. 7), the upper chuck 9 grips the weight lifting rod 4 and descends together with the weight lifting rod 4. It is configured.

Further, while the lower chuck 10 grips the weight lifting rod 4, the upper chuck 9 releases the weight lifting rod 4, and the piston rod 8a of the jack body 8 extends to rise along the weight lifting rod 4. (See FIG. 8) In addition, while the lower chuck 10 grips the weight lifting rod 4, the upper chuck 9 is configured to descend along the weight lifting rod 4 by contraction of the piston rod 8a (see FIG. 8). See Figure 6).

When the upper chuck 9 grips the weight lifting rod 4 and the piston rod 8a of the jack body 8 extends, the lower chuck 10 lifts the weight 3 via the weight lifting rod 4 (see FIG. 3). , is arranged to release the weight lifting rod 4 .

Also, when the upper chuck 9 grips the weight lifting rod 4 and the piston rod 8a of the jack body 8 contracts, the weight lifting rod 4 descends (see FIG. 5), and when the upper chuck 9 grips the weight lifting rod 4 is released and the extension of the piston rod 8a of the jack body 8 raises it along the weight lifting rod 4 (see FIG. 8), the lower chuck 10 is configured to grip the weight lifting rod 4. .

The upper chuck 9 and the lower chuck 10 will be described in more detail. The upper chuck 9 has a chuck body 9a formed in the air, and is incorporated in the chuck body 9a so as to be movable in the axial direction of the weight lifting rod 4, An engagement key 9b for gripping and releasing the lower side of the node 4a of the weight lifting rod 4, and an engagement key 9b which is built in the weight lifting rod 4 so as to extend and contract in the vertical direction of the axis. A jack 9c that pushes up the weight lifting rod 4 and a spring 9d that always pushes down the engagement key 9b in the axial direction of the weight lifting rod 4 are provided.

An intermediate rib 9e is formed inside the chuck body 9a, and a jack 9c and a spring 9d are built in the lower and upper sides of the intermediate rib 9e, respectively. A tapered surface 9f inclined toward the weight lifting rod 4 is formed in an inverted truncated cone shape. The weight lifting rod 4 vertically penetrates through loose holes formed in the center portions of the chuck body 9a, the jack 9b, and the engagement key 9b.

In such a configuration, the spring 9d constantly pushes down the engaging key 9b in the axial direction of the weight lifting rod 4, so that the engaging key 9b moves along the tapered surface 9f of the intermediate rib 9e toward the weight lifting rod 4 side. , and engages with the lower side of the node 4a of the weight lifting rod 4. As shown in FIG. That is, the upper chuck 9 grips the lower side of the joint 4a of the weight lifting rod 4 (see FIG. 5). As a result, the piston rod 8a of the jack body 8 is extended, so that the weight 3 can be lifted by one stroke length of the piston rod 8a via the weight lifting rod 4. As shown in FIG.

In addition, the jack 9c pushes up the engagement key 9b in the axial direction of the weight lifting rod 4, so that the engagement key 9b slides in the direction opposite to the weight lifting rod 4 while being pushed up, and the weight lifting rod 4 is removed from the lower side of the joint portion 4a. That is, since the engagement key 9b releases the weight lifting rod 4, the upper chuck 9 descends to its original position along the weight lifting rod 4 as the piston rod 8a of the jack body 8 contracts (see FIG. 6). .

At this time, since the lower chuck 10 described later holds the weight lifting rod 4 , the weight lifting rod 4 does not descend together with the upper chuck 9 .

Below, the engagement key 9b grips the weight lifting rod 4 and the piston rod 8a of the jack body 8 extends to lift the weight 3 via the weight lifting rod 4 (see FIG. 5), and The joint key 9b releases the weight lifting rod 4, and the piston rod 8a of the jack body 8 contracts, whereby the upper chuck 9 descends along the weight lifting rod 4 (see FIG. 6)) is repeated. As a result, the weight 3 dropped onto the pile head A can be lifted up to the original height from which it dropped.

The lower chuck 10 includes a chuck body 10a formed in the air, and an engagement key that is incorporated in the chuck body 10a so as to be movable in the vertical direction of the weight lifting rod 4, and that grips and releases the weight lifting rod 4. 10b, a jack 10c which is built in the weight lifting rod 4 so as to be extendable and retractable in the axial direction of the weight lifting rod 4 and which pushes the engagement key 10b in the axial direction of the weight lifting rod 4; and a spring 10d that pushes down the shaft.

An intermediate rib 10e is formed inside the chuck body 10a, and a jack 10c and a spring 10d are built in the lower and upper sides of the intermediate rib 10e, respectively. A tapered surface 10f inclined toward the weight lifting rod 4 is formed in an inverted truncated cone shape on the contact surface between the intermediate rib 10e and the engaging key 10b. The weight lifting rod 4 vertically penetrates loose holes formed in the center portions of the chuck body 10a, the jack 10c and the engagement key 10b.

In such a configuration, the spring 10d constantly presses the engagement key 10b in the axially downward direction of the weight lifting rod 4, so that the engagement key 10b moves toward the weight lifting rod 4 side along the tapered surface 10f of the intermediate rib 10e. , and engages with the lower side of the node 4a of the weight lifting rod 4. As shown in FIG. That is, the lower chuck 10 grips the lower side of the node 4 a of the weight lifting rod 4 .

As a result, the upper chuck 9 releases the suspension rod 4 and can be lifted (see FIG. 6) and lowered (see FIG. 8) along the weight lifting rod 4 by extension and contraction of the piston rod 8a of the jack body 8. .

In addition, the jack 10c pushes up the engaging key 10b in the axial direction of the weight lifting rod 4, so that the engaging key 10b slides in the direction opposite to the weight lifting rod 4 while being pushed up. release the

As a result, the upper chuck 9 grips the weight lifting rod 4 and descends together with the weight lifting rod 4 by contracting the piston rod 8a of the jack body 8 (see FIG. 7). That is, the weight lifting rod 4 can be lowered by one stroke length of the piston rod 8a of the jack body 8 .

Thereafter, in a state in which the lower chuck 10 releases the weight lifting rod 4, the engagement key 9b grips the weight lifting rod 4, and the piston rod 8a of the jack body 8 is contracted, whereby the weight lifting rod 4 is lifted. With the downward movement (see FIG. 7) and the lower chuck 10 gripping the weight lifting rod 4, the engagement key 9b releases the weight lifting rod 4 and the upper chuck 9 engages the piston rod of the jack body 8. By repeating the upward motion (see FIG. 6) along the weight lifting rod 4 due to the extension of 8a, the weight lifting rod 4 can be lowered to the position of the weight 3 that has fallen to the pile head A. .

Reference numeral 11 denotes a guide device that guides the weight 3 while the weight 3 falls on the pile head A and while the weight 3 dropped on the pile head A is lifted to the original height, and is a guide rail 11a. and a guide roller 11b, the guide rail 11a is installed inside the column 1a of the frame 1, the guide roller 11b is installed on the weight 3 and the weight chuck 7, and travels on the guide rail 11a. ing.

Reference numeral 12 denotes a weight catching device that catches the weight 3 in the air to prevent the weight 3 from rebounding when the weight 3 drops onto the pile head A and jumps up. The weight catching device 12 includes a weight catching holder 13 , an electro-permanent holder 14 and a weight drop prevention stopper 15 , and is mounted on a portal frame 16 mounted on the upper end of the frame 1 .

The weight catching holder 13 and the permanent electromagnetic holder 14 are installed on the upper frame 1a of the frame 1 and the upper frame 16a of the portal frame 16, respectively. placed in between.

Further, the weight catching holder 13, the permanent electromagnetic holder 14 and the weight drop prevention stopper 15 are installed on the same vertical line, and the central portions of the weight catching holder 13, the permanent electromagnetic holder 14 and the weight drop prevention stopper 15 are A weight catching rod 17, which will be described later, penetrates vertically, and a weight drop prevention stopper 15 freely moves up and down along the weight catching rod 17 between the weight catching holder 13 and the permanent electromagnetic holder 14. .

In addition, a recess 13a is formed on the upper end side of the weight catching holder 13, in which the weight drop prevention stopper 15 is inscribed. It is formed in a truncated cone shape, and a loose hole 13b through which the weight catching rod 17 penetrates is formed at the bottom.

The weight drop prevention stopper 15 includes a plurality of spheres 18 and a sphere holder 19 that holds the spheres 18. The sphere holder 19 has the largest outer diameter at the upper end corresponding to the shape of the recess 13a, and extends toward the lower end. It is formed in the shape of a truncated inverted truncated cone whose diameter gradually decreases.

A loose hole 19a through which the weight catching rod 17 penetrates is formed in the central portion of the sphere holder 19, and a sphere containing portion 19c having a concavely curved inner peripheral surface is formed between the loose hole 19a and the outer peripheral surface 19b. A plurality of them are formed at equal intervals in the circumferential direction and the vertical direction of the sphere holder main body 19 .

The loose hole 19a side and the outer peripheral surface 19b side of each ball storage portion 19c are open, and the ball 18 is stored in each ball storage portion 19c. Each sphere 18 can rotate freely within the sphere containing portion 19c, and can move freely toward the loose hole 19a side and the outer peripheral surface 19b side. It is formed in such a size that a part of it always protrudes into the opening.

The permanent electromagnetic holder 14 has a loose hole 14a through which the weight catching rod 17 penetrates in the center, and is equipped with a buffer member such as a coil spring or vibration-proof rubber for reducing the impact when the weight 3 is dropped. It is installed on the upper frame 16 a of the frame 16 .

Furthermore, the permanent electromagnetic holder 14 attracts the weight fall prevention stopper 15 only when a magnetic force is generated by energization. It can be done by control.

A plurality of weight catching rods 17 are arranged at equal intervals around the weight lifting rod 4 , and the lower end of each weight catching rod 17 is connected to the upper end peripheral edge of the weight 3 . In addition, the upper end side of each weight catching rod 17 continuously penetrates the loose holes 13a, 15a and 14a of the weight catching holder 13, the weight drop prevention stopper 15 and the permanent electromagnetic holder 14 of the weight catching device 12. is doing.

In such a configuration, when the weight 3 suspended from the tip of the weight lifting rod 4 falls to the pile head A and bounces up at the pile head A, when the energization to the permanent electromagnetic holder 14 is cut off, The weight drop prevention stopper 15 leaves the permanent electromagnetic holder 14 and falls into the recess 13 a of the weight catching holder 13 along the weight catching rod 17 .

At the same time that the weight drop prevention stopper 15 falls into the recessed portion 13a of the weight catching holder 13, the spherical body 18 is strongly pushed toward the loose hole 15a by the inner peripheral surface of the recessed portion 13a of the weight catching holder 13. By projecting into the loose hole 15a and strongly gripping the weight catching rod 17, the rib band of the weight 3 is held down.

The permanent electromagnetic holder 14 that attracts the weight drop prevention stopper 15 is attached to the upper frame 16a of the gate-shaped frame 16 via a buffer member such as a coil spring or anti-vibration rubber. The weight 3 will not drop by mistake.

FIGS. 11(a) to 11(c) show modified examples of the weight drop prevention stopper, in which a plurality of slits 20c are formed in the piece holder 20 between the loose hole 20a and the outer peripheral surface 20b of the piece holder 20. A wedge-shaped piece 21 is inserted into each slit 20c formed at equal intervals in the circumferential direction.

In such a configuration, the permanent electromagnetic holder 14 generates a magnetic force, so that the weight drop prevention stopper 15 sticks to the permanent electromagnetic holder 14, and when the energization to the permanent electromagnetic holder 14 is cut off, the weight catching holder 13 Then, each wedge-shaped piece 21 is strongly pushed toward the loose hole 20a by the inner peripheral surface of the recessed portion 13a, the end of each wedge-shaped piece 20 protrudes into the loose hole 20a, and the weight 3 By strongly gripping the weight catching rod 17 which jumped up together with the weight 3, rebanding of the weight 3 is prevented.

The present invention relates to a pile rapid loading test for confirming the bearing capacity of the pile from the axial pushing force of the pile acting on the pile head by a weight falling on the pile head that actually protrudes from the ground surface. A dropped weight can be hoisted to its original height very safely and quickly.

1 frame 2 upper frame 3 weight 4 weight lifting rod 5 weight lifting jack 6 node 6a taper 7 weight chuck 8 jack body 8a piston rod 9 upper chuck 9a chuck body 9b engagement key 9c jack 9d spring 9e intermediate Rib 9f Taper 10 Lower chuck 10a Chuck main body 10b Engaging key 10c Jack 10d Spring 10e Intermediate rib 10f Taper 11 Weight guide device 11a Guide rail 11b Guide roller 12 Weight catching device 13 Weight catching holder 13a Concave portion 13b Loose hole 14 Permanent Electromagnetic holder 14a Loose hole 15 Weight drop prevention stopper 16 Gate frame 16a Upper frame 17 Weight catching rod 18 Sphere 19 Sphere holder 19a Loose hole 20 Piece holder 21 Wedge-shaped piece

Claims (4)

In a rapid loading test device for piles that confirms the bearing capacity of a pile from an axial pushing force acting on the pile head by a weight falling on the pile head, a frame body erected near the pile head, and the frame A weight lifting jack that is installed on the body and lifts the weight that has fallen on the pile head to the original height via the weight lifting rod, and the weight is detachably suspended at the end of the weight lifting rod. and a guide device for guiding the weight. An upper chuck and a lower chuck for gripping and releasing a weight lifting rod, when the weight lifting jack lifts the weight, the upper chuck grips the weight lifting rod and the lower chuck lifts the weight the lower chuck is configured to grip the weight lifting rod when the rod is released and the upper chuck releases the weight lifting rod and descends with the contraction of the weight lifting jack. Rapid loading test equipment for piles characterized by 2. The rapid loading test apparatus for piles according to claim 1, wherein a plurality of nodes are provided on the outer periphery of the weight lifting rod at equal intervals in the axial direction of the weight lifting rod. Load test equipment. 3. The rapid loading test apparatus for piles according to claim 1 or 2, further comprising a weight catching device for catching in mid-air the weight jumped up from the top of the pile. A rapid loading test apparatus for piles according to any one of claims 1 to 3, characterized by comprising a remote device for remotely operating said weight lifting jack and said weight gripping chuck. .

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