JPH10274576A - Load testing device and load testing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load testing device and a load testing method having the advantage of a stanamic test for static-dynamic tests and facilitating adjustment of weight launching force without using explosive. SOLUTION: Compressed air stored in a pressure vessel 21 of a weight launching device 20 is rapidly released by opening a solenoid valve 24. The compressed air enters a cylinder part 13, provided inside a weight 11, at a stroke through a compressed air discharge pipe 22 so as to launch the weight 11 by its expansion pressure. Reaction of this launching is transmitted as load to a pile head 2 to execute a load test.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load test apparatus and a load test method, and more particularly, to a rapid loading method in which a pile is loaded on a head and a supporting force of the pile is determined from a relationship between a load and a displacement. The present invention relates to an apparatus and a method for a test.

[0002]

2. Description of the Related Art As a load test method for a pile, a static test in which a load is continuously applied to a pile head by a reaction force device and a dynamic test in which a large impact force is instantaneously applied are employed. The former is inferior in economy and speed, while the latter has a problem that the pile head may be damaged. In recent years, a STATNAMIC TEST has been developed and implemented as a loading test method to solve the above problems.

The static test is a rapid loading test in which a weight set on a pile head is launched by gas pressure generated by the combustion of explosives, and the pile head is loaded by a reaction force thereof. It does not require a large-scale reaction force device. Since the time for applying the reaction force to the pile head is as long as 30 to 50 times of the dynamic test, there is an advantage that the pile head is not likely to be damaged.

[0004]

However, in the static test, explosives are used, which is dangerous, is subject to various regulations, has a large explosion sound, and has a problem that adjustment of the launching force of the weight is troublesome. there were.

Accordingly, an object of the present invention is to provide a load test apparatus and a load test method which have the advantage of a static test over a static / dynamic test, and which can easily adjust the launching force of a weight without using explosives. It is in.

[0006]

A load test apparatus according to the present invention is characterized by comprising a weight, a weight launching apparatus which launches the weight by the expansion pressure of compressed air, and loads the weight by a reaction force of the launch. And Further, the loading test method according to the present invention is characterized in that a weight is launched by the expansion pressure of compressed air and loaded by a reaction force of the launch.

That is, the weight is launched by the pressure generated by suddenly releasing the compressed air, and the reaction force is transmitted as a load to a pile head or the like. The launching force can be adjusted by the compression pressure of the compressed air, the amount of the compressed air, the discharge speed of the compressed air, the weight of the weight, and the like.

According to another aspect of the present invention, there is provided a load test apparatus, wherein the weight is caused by an electromagnetic repulsive force between the weight, a first coil provided on the weight, and the first coil generated by energization. And a second coil loaded by a reaction force of the launch. Further, another loading test method according to the present invention is characterized in that a weight is launched by an electromagnetic repulsion between coils generated by energization, and the weight is loaded by the reaction of the launch.

That is, current is applied to the coils on the weight side and the pile head side, etc., and the weight is launched by the electromagnetic repulsion generated between the coils, and the reaction force is transmitted as a load to the pile head or the like. It is. The repulsive force can be adjusted by the number of turns of the coil, the magnitude of the current, the weight of the weight, and the like.

The object of the load test is mainly a pile, but the present invention is not particularly limited to this, and may be, for example, the ground or various structures. Further, the present invention can be applied not only to vertical loading but also to horizontal loading.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing a state in which a load test apparatus 10 according to the present invention is set on a head 2 of a pile 1 in a partial cross section. The load test apparatus 10 is composed of a weight 11 having a columnar outer shape made of concrete or iron, and a weight launching apparatus 20. The weight launching apparatus 20 includes a pressure vessel 21 for storing compressed air, and a compression extending upward from the vessel 21. An air discharge pipe 22 is provided, and a remote controllable solenoid valve 24 is interposed at the boundary between the container 21 and the discharge pipe 22.

Inside the weight 11, there is provided a space along the axis line which is opened only downward and extends along the axis. After the diameter is reduced, it is extended upward to a constant diameter and divided into a cylinder 13 for accommodating the compressed air discharge pipe 22. A piston portion 23 is provided at an upper end of the discharge tube 22,
The piston part 23 is a weight 11 that defines the cylinder part 13.
Slidably in contact with the inner peripheral surface of the piston part 23, and a gap between the upper part of the piston part 23 and the inner part of the discharge pipe 22 and the lower part of the piston part 23 and the outer part of the discharge pipe 22 below the piston part 23. Be airtight.

A load cell 3 for measuring a load is provided between the pressure vessel 22 and the pile head 2, and a vertical displacement of the pile 1 A laser sensor is installed as a displacement meter for measuring the quantity (not shown).

In the test, first, compressed air is injected into the pressure vessel 21 by a compressor (not shown), and then the solenoid valve 24 is opened by remote control.
As a result, the compressed air rapidly expands through the discharge pipe 22 and squeezes above the cylinder portion 13 of the weight 11, and the expansion pressure launches the weight 11 as shown in FIG. The load is transmitted to the pile head 2 via the device 20. The compressed air discharge pipe 22 guides the launch and fall of the weight 11, and the piston section 23 prevents pressure release.

In the above method, the loading time during which the reaction force is applied to the pile head 2 is longer than the static test and is closer to the static test, so that the pile 1 and the ground are sufficiently integrated and reacted. Therefore, the accuracy of the determination of the supporting force of the pile 1 can be improved.

FIG. 3 shows another load test apparatus 3 according to the present invention.
It is explanatory drawing which shows the state which set 0 to the head part 2 'of the pile 1' by a partial cross section. The loading test device 30 includes a cylindrical weight 31 made of concrete, a first coil 32 projecting from the bottom surface of the weight 31 concentrically with the weight 31, and a first coil 32.
A load cell 3 'on the pile head 2' so as to concentrically surround the
And a second coil 33 provided therebetween. In addition,
The inner (radial) coil may be provided on the pile 1 'side, and the outer (radial) coil may be provided on the weight 31 side.

In the test, the first coil 32 and the second coil 33 are simultaneously energized to generate an electromagnetic repulsion between the first coil 32 and the second coil 33, respectively. The repulsive force launches the weight 31,
The reaction force of this launch is transmitted as a load to the pile head 2 ′ via the second coil 33.

The weight can be adjusted by, for example, appropriately stacking disk-shaped blocks (not shown) on the upper surfaces of the weights 11 and 31.

[0020]

As described above, the load test apparatus and the load test method according to the present invention have advantages over static and dynamic tests of a static test, such as not requiring a large-scale reaction force device. Since explosives are not used, it is safe, there are no various regulations and no explosion, and furthermore, the use of a measurable expansion pressure of compressed air or an electromagnetic repulsion makes it easy to adjust the launching force of the weight.

Further, since the compressed air serves as a cushion for receiving the falling weight, the hitting of the pile by the falling weight can be prevented, which is safe. The method using an electromagnetic coil can also receive the falling weight with an electromagnetic force, and thus the same effect can be expected.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing, in a partial cross section, a state in which a load test device according to the present invention is set on a pile head.

FIG. 2 is an explanatory view showing a state in which a weight is launched.

FIG. 3 is an explanatory view showing, in partial cross section, a state in which another load test device according to the present invention is set on a pile head.

[Explanation of symbols]

 1,1 'pile 2,2' (pile) head 3,3 'load cell 10,30 load test device 11,31 weight 13 cylinder portion 12 weight launch device 21 compression container 22 compressed air discharge pipe 23 piston portion 24 electromagnetic Valve 32 First coil 33 Second coil

Claims (4)

[Claims] 1. A load test apparatus comprising: a weight; and a weight launching device that launches the weight by the expansion pressure of compressed air and loads the weight by a reaction force of the launch. 2. A loading test method, wherein a weight is launched by the expansion pressure of compressed air and loaded by a reaction force of the launch. 3. An electro-magnetic repulsive force between a weight, a first coil provided on the weight, and the first coil generated by energizing, launches the weight,
And a second coil loaded by a reaction force of the launch. 4. A loading test method characterized in that a weight is launched by an electromagnetic repulsion between coils generated by energization and loaded by the reaction of the launch.