JP2010223894A - Compact load tester and testing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe, light and compact high-speed load tester and an impact load tester, and to provide testing method thereof. <P>SOLUTION: The high-speed load tester 1 includes and includes a test pile 3 for receiving a load at a top; a plurality of reference piles 4, as a reference for measuring a displacement of the test pile 3; a loading plumb 6; a frame 7 for supporting the loading plumb 6; a loading fluid pressure cylinder 8, mounted under the plumb 6 whose body downwardly has a rod 9 and applying the load from a tip of the rod 9 to the test pipe 3 via a load detector 10 by supplying a fluid pressure to the body; reference beams 5 mounted to a plurality of the reference piles 4 and attached to a displacement detector 11; and a measurement apparatus 12 for measuring the displacement and the carried load of the test pile 3. The high-speed load tester can be switched to the impact load tester 2 by replacing a portion of fixtures. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a small load test apparatus and a test method thereof, and more particularly to a small load test apparatus and a test method for measuring the strength of a ground by rapid loading or impact loading on a test pile with a weight.

For civil engineering structures and building foundations, if the ground cannot directly support the load of the structure, the pile will be driven into the ground and the load on the structure will be affected by the supporting force of the tip of the pile and the frictional force of the pile circumference. I try to support it. The main piles used here are steel pipe piles and concrete piles for large structures, wooden piles for small structures such as waterway foundations and residential foundations.
Pile design is based on prior ground survey information, such as soil composition such as sand ground and viscous ground, N value, which is an index indicating the strength of the soil, and soil tests that examine the physical and mechanical properties of the soil. Done.

When a structure such as a bridge with high importance or the force supported by a pile is large, a pile loading test is performed for the purpose of confirming the validity of the design during construction. The pile loading test is to check whether the ground can support the pile by actually loading the pile equivalent to the load of the building itself and measuring the amount of settlement of the pile at that time.
In the case of wooden piles, since the importance of the target structure is relatively low and the necessary supporting force is small, in most cases, the test as performed in the case of the important structure is not performed.
The pile loading test is performed after driving the pile to a certain depth. When force is applied to the pile, the pile will sink, but in the range where the ground can support the pile, the settlement will be small, but if it exceeds the limit, it will sink significantly.

The pile loading test is to measure the amount of settlement of a pile by applying a load or impact load to the pile by some method. There are six types of pile loading tests, such as indentation testing, tip loading testing, pull-out testing, lead orthogonal number loading testing, rapid loading testing, and impact loading testing.
Among them, the rapid loading test method is a test in which a dynamic load is applied to the pile head and does not require a large-scale reaction force device and has the merit that the measurement time is as short as a few seconds. It requires somewhat advanced technology.
The impact loading test method, like the rapid loading test method, is a test in which a dynamic load is applied to the pile head, but the measurement time is shorter than the rapid loading test method, and a more advanced analysis technique than the rapid loading test method is required. Cost.

  Conventionally, a vertical loading test of a pile in which a large-scale reaction device is installed and the pile is pushed statically is common. In this test method, it takes 1 to 10 days to prepare a large-scale reaction device, and the test time requires at least one day. Therefore, the development of a test device that can easily calculate the bearing capacity in a short time is desired, and the development of a rapid load test, an impact load test device, and the like has been promoted.

  These methods have the advantage that the test can be completed in a very short time, but because the test equipment is intended for relatively large piles (pile that requires a large bearing capacity), the equipment becomes large. There are many safety problems to handle the reaction force due to the power source, heavy load, etc. due to combustion pressure due to high pressure gas or chemical reaction, which cannot be tested in a narrow work space, depending on the load loading time to load on the pile , The material of the pile body may be restricted, and there are problems such as the construction method of the pile may be restricted.

  As a small load test, there is one disclosed in Utility Model Registration No. 3111906. This device is a compact loading test device that allows the main body to be miniaturized by obtaining reaction force from the ground, and is a method of obtaining the indentation reaction force when press-fitting a press-fitting jig into the ground from an anchor penetrating the ground. For this reason, it takes a lot of labor to fix the anchor to the ground, and it has a problem that it is difficult to apply to the soft ground where it is difficult to fix the anchor.

Utility Model Registration No. 3111906

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a rapid loading test apparatus, an impact loading test apparatus, and a testing method thereof that can be made safe and lightweight and downsized.

  The present invention is a test pile that receives a load at the top, a plurality of reference piles that serve as a reference for measuring the displacement of the test pile, a weight for weighting, and a frame that supports the weight for weighting, A body part is mounted on the lower part of the heavy cone with the rod facing downward, and a fluid pressure cylinder for loading that applies a load from the tip of the rod to the test pile via a load detector by supplying fluid pressure to the body part, A reference beam mounted on the plurality of reference piles to which a displacement detector is attached, and a measuring device for measuring the displacement and load load of the test pile are characterized.

  The present invention also provides a test pile that receives a drop load at the top, a plurality of reference piles that serve as a reference for measuring the displacement of the test pile, a falling weight, and the falling weight. The falling weight is held via a frame supporting the frame and a pulley attached to the frame, and the falling pressure weight is dropped during the test to adjust the damping pressure of the impact load. A winch that applies an impact load to the test pile via a cylinder and a load detector; a reference beam that is mounted on the plurality of reference piles and to which a displacement detector is attached; and for measuring displacement and loading load of the pile And a measuring device.

  The pile is made of wood, the fluid pressure cylinder for loading is an air cylinder, the reference beam connects a plurality of the reference piles via the upper side of the test pile, and the test pile corresponding position is A plurality of displacement detectors are mounted.

  Further, the present invention includes a setting step of sinking a test pile receiving a load on a top to a predetermined depth in a measurement target ground, a step of bringing a tip of a hydraulic fluid pressure cylinder rod into contact with the top of the test pile, and the load A stage in which the weight of the weighting weight supported by the frame is introduced to the top of the test pile by introducing compressed air into the hydraulic cylinder for use, and the test pile is displaced. And measuring the displacement of the test pile with a displacement detector attached to the displacement beam.

  In addition, the present invention also includes a setting stage in which a test pile that receives an impact load at the top is submerged to a certain depth in the measurement target ground, and a wire that passes through a pulley that is attached to a frame that supports a weight for falling down by a winch. Rolling up and holding the falling weight at a reference height, and releasing the wire wound around the winch to allow the falling weight to adjust the damping force of the impact load. And a step of measuring a displacement of the test pile due to an impact load applied to the test pile through the damping force adjusting fluid pressure cylinder and a load detector. .

The test apparatus according to the present invention uses a reaction force generator that can be transported by compressed air less than high-pressure gas and human power as the power source, so it is compact, lightweight and excellent in mobility, and because the test apparatus is small, the work space is small. This is very effective for small and small structures.
In addition, since the weight of the device is light, testing is possible even on poor ground, and maintenance is easy, safety is high, and workability is excellent by using air pressure less than high-pressure gas.
In addition, the test apparatus according to the present invention can improve the load that can be loaded by increasing the compressed air capacity and the reaction force body, and by combining these both, a fine loading load and loading time can be set. Since the loading time and installation time can be greatly shortened, the construction period and cost can be shortened compared with the conventional static vertical loading test.

It is the schematic which shows Example 1 of this invention. It is the schematic which shows Example 2 of this invention.

FIG. 1 is a schematic view of a rapid loading test apparatus.
The rapid loading test apparatus 1 according to the present invention includes a wooden test pile 3 that receives a load at the top, two reference piles 4 that serve as a reference for measuring the displacement of the test pile 3, a weight 6 for weighting, and a weight A frame 7 for supporting the weight 6 for use and a main body portion are mounted on the lower portion of the heavy cone 6 with the rod 9 facing downward, and air pressure is supplied to the main body portion from the tip of the rod 9 via the load detector 10. A load air cylinder 8 for applying a load to the test pile 3, a reference beam 5 attached to a plurality of reference piles 4 to which a displacement detector 11 is attached, and a measurement for measuring the displacement and loading load of the test pile 3 And the device 12.

  In addition, the impact loading test apparatus 2 according to the present invention includes a wooden test pile 3 that receives a falling rock load at the top, two reference piles 4 that serve as a reference for measuring the displacement of the test pile 3, and a falling pile weight. The falling weight 6 is held via a weight 6, a frame 7 that supports the falling weight 6, and a pulley 13 attached to the frame 7. The winch 15 for applying an impact load to the test pile 3 via the air cylinder 8 for adjusting the damping force of the impact load and the load detector 10 and the displacement detector 11 attached to the plurality of reference piles 4 are attached. The reference beam 5 and the measuring device 12 for measuring the displacement and load load of the pile are included.

The reference beam 5 connects a plurality of reference piles 4 via the upper side of the test pile 3, and two displacement detectors 11 are mounted at corresponding positions of the test pile 3.
Compressed air from the compressor 16 is used as a power source for pressurization of the air cylinder 8. The compressed air from the compressor 16 is regulated by a regulator and sent to the pressure accumulation tank 17. The accumulator tank 17 is for supplying a stable pressure to the air cylinder 8.
Each of the weights 6 has a weight of 5, 10, 25 kg, and an arbitrary weight can be set. Along with the pressure adjustment of the compressed air, it is possible to set a finer load load.
The weight 6 is lifted upward by the air cylinder 8, but when the weight 6 is inclined, the center of gravity changes and a predetermined load cannot be secured. Therefore, the weight guide device 19 prevents the center of gravity of the weight 6 from changing. I try to support it.
The weight 6 and the air cylinder 8 are suspended from the frame 7 via a chain block. The installation method of the frame 7 enables testing in an irregular work space or a narrow work space.

In the loading test, it is necessary to accurately measure the load acting on the test pile 3 and the displacement (settlement) of the test pile 3, and it is important to install the detector at a stable location. Among them, the displacement detector 11 is particularly important and is installed on the reference beam 5. A device for stably fixing the reference beam 5 is a reference beam fixing device 18.
The reference beam fixing device 18 is installed on the pile head of the reference pile 4 which is the same standard as the test pile 3, and stably fixes the reference beam 4 by tightening from four directions to the pile head. ing. In addition, the load detector 10 installed on the upper part of the test pile 3 is also fixed to the test pile head fixing device 21 in a stable state.

FIG. 2 is a schematic diagram of the impact loading test apparatus 2.
The impact loading test apparatus 2 can be switched by changing the arrangement of the rapid loading test apparatus 1 or rearranging some equipment.
In the impact loading test apparatus 2, the air cylinder 8 is reversed and fixed and used as the cushion cylinder 8. Arbitrary damping force can be set in the cushion cylinder 8 by sending compressed air from two directions. In addition, an arbitrary load loading time can be adjusted by the stroke adjusting device 20.
The weight 6 is raised by the electric winch 15 and is naturally dropped. At this time, a heavy cone guide device 19 is provided to prevent the drop direction from changing.

Hereinafter, the rapid loading test method and the impact loading test method will be described.
As shown in FIG. 1, in the rapid loading test, first, a test pile 3 that receives a load at the top is placed on a measurement target ground to a certain depth. Two reference piles 4 serving as a reference for measuring the displacement of the test pile 3 are placed in advance at predetermined positions.
Next, the tip of the rod 9 of the load air cylinder 8 is brought into contact with the top of the test pile 3 to pressurize the test pile 3. As a power source for pressurization, the compressed air from the compressor 16 is regulated by a regulator and sent to the pressure accumulation tank 17. The accumulator tank 17 is for supplying a stable pressure to the cylinder 8.
The compressed air accumulated in the pressure accumulating tank 17 is stopped by an electromagnetic valve in front of the cylinder 8. When the relay switch is turned on, compressed air is sent to the cylinder 8 and the piston of the cylinder 8 is projected.
Since the manual switching valve cannot send compressed air quickly, an electromagnetic valve is used to send compressed air quickly. The quick loading test is based on how fast compressed air is sent into the cylinder 8. The protruding speed of the piston of the cylinder 8 differs depending on the pressure of the compressed air and the speed at which the compressed air is fed. The faster the projecting speed of the piston of the cylinder 8, the less the weight 6 to be prepared for the intended load.

The piston protrusion of the cylinder 8 pushes the weight 6 upward, and at the same time, a force is applied to the pile head of the lower test pile 3. Using this force as a loaded load, the test pile 3 is displaced, and the displacement of the test pile 3 is measured by the displacement detector 11 attached to the reference beam 5 attached to the two reference piles 4.
After the piston of the cylinder 8 protrudes a certain amount, it is necessary on the principle of the test to release the compressed air inside the cylinder 8. The stroke detector 20 detects a certain amount of protrusion, and the detection stroke can be set to an arbitrary amount. The signal from the detector is sent to the relay switch again, and the solenoid valve is turned OFF to release the compressed air in the cylinder.

Next, the impact loading test method will be described.
As shown in FIG. 2, a test pile 3 that receives a load at the top in an impact loading test is placed on the ground to be measured to a certain depth. Two reference piles 4 serving as a reference for measuring the displacement of the test pile 3 are placed in advance at predetermined positions.
Next, the wire 14 that passes through the pulley 13 attached to the frame 7 that supports the falling weight 6 is wound up by the electric winch 15 to hold the falling weight 6 at the reference height.
In the case of an impact loading test, the air cylinder 8 is inverted and fixed, and is used as a cushion cylinder 8 in which compressed air can be sent from two directions to set an arbitrary damping force. An arbitrary load loading time can be adjusted by the stroke detector 20.
The falling cone weight 6 wound up by the electric winch 15 is dropped on the rod 9 of the cylinder, but a heavy cone guide device 19 is provided to prevent the falling direction from changing.
The installation method of the measuring device 12 is the same as in the case of the rapid loading test.

This test device differs from the conventional test method in that it uses compressed air that is not subject to high-pressure gas and a reaction force that can be transported by human power as the power source.
Since the test equipment is small, it requires less work space and is very effective when the structure itself is small. In addition, since the weight of the device is light, it is possible to test even on poor ground.
By using air pressure that is not subject to high-pressure gas, maintenance is easy, safety is high, and workability is excellent.
In this test apparatus, a fine loading load and loading time can be set by a combination of the compressed air capacity and the weight 6.
For analysis of test results, it is possible to apply the unloading point method, which is also used in general rapid loading tests.
Similar to the normal rapid loading test, the necessary weight 6 can be as small as 5 to 20% of the static indentation test as compared with the conventional static loading test.

  In addition, this test apparatus can be applied to an impact loading test with a long loading time. Specifically, by dropping the reaction mass into the cylinder and impact-loading it on the pile foundation via the compressed air accumulated in the cylinder, the loading time can be made longer than the normal impact loading test. Therefore, it is easy to remove the dynamic action that requires a complicated analysis method in the impact loading test, and the static bearing force characteristics can be calculated.

Since this test apparatus can greatly shorten the loading time and installation time, it can shorten the construction period and cost compared with the conventional static vertical loading test.
Table 1 shows a comparison between this test apparatus and the conventional method.
As shown in Table 1, in the conventional static loading test, it took 2 to 13 days for the device / assembly disassembly and 4 hours or more for the test measurement time. Dismantling takes about 0.5 days and the test measurement time ends in seconds.
The cost of the test, which was 200,000 to 1,000,000 yen or more according to the conventional method, is only about 150,000 yen.

DESCRIPTION OF SYMBOLS 1 Rapid loading test apparatus 2 Impact loading test apparatus 3 Test pile 4 Reference pile 5 Reference beam 6 Weight 7 Frame 8 Air cylinder, cushion cylinder 9 Rod 10 Load detector 11 Displacement detector 12 Measuring instrument 13 Pulley 14 Wire 15 Electric winch 16 Compressor 17 Accumulation tank 18 Reference beam fixing device 19 Weight guide device 20 Stroke detector 21 Test pile head fixing device

Claims (6)

A test pile receiving a load at the top,
A plurality of reference piles serving as a reference for measuring the displacement of the test pile;
A weight for weighting;
A frame for supporting the weight for weighting;
A main body part is mounted on the lower part of the heavy cone with the rod facing downward, and a fluid pressure cylinder for loading that applies a load from the tip of the rod to the test pile via a load detector by supplying fluid pressure to the main body part,
A reference beam mounted on the plurality of reference piles to which a displacement detector is attached;
A measuring device for measuring the displacement and loading load of the test pile;
A small load testing apparatus comprising: A test pile that receives a falling load on the top,
A plurality of reference piles serving as a reference for measuring the displacement of the test pile;
A falling weight,
A frame for supporting the falling weight,
The falling weight is held via a pulley attached to the frame, and a falling pressure adjusting fluid pressure cylinder and load detector are provided by dropping the falling weight when testing. A winch for applying an impact load to the test pile via,
A reference beam mounted on the plurality of reference piles to which a displacement detector is attached;
A measuring device for measuring displacement and loading load of the pile;
A small load testing apparatus comprising:   3. The small load testing apparatus according to claim 1, wherein the test pile and the reference pile are made of wood, and the fluid pressure cylinder for loading is an air cylinder. 4.   The said reference beam connects several said reference piles via the upper direction of the said test pile, The several displacement detector is mounted | worn with the said test pile corresponding position. 4. The small load test apparatus according to any one of 3 above. A set stage in which a test pile that receives a load at the top is submerged to a certain depth in the ground to be measured;
Abutting the tip of the fluid pressure cylinder rod for loading against the top of the test pile;
Applying a weight of a weight for weight supported by a frame to the top of the test pile by introducing compressed air into the fluid pressure cylinder for loading, and displacing the test pile;
Measuring the displacement of the test pile with a displacement detector attached to a displacement beam attached to the plurality of reference piles;
A compact loading test method comprising: A set stage in which a test pile that receives an impact load at the top is submerged to a certain depth in the ground to be measured;
A step of winding a wire via a pulley attached to a frame that supports a falling weight for weight by a winch to hold the falling weight at a reference height;
Releasing the wire wound around the winch and dropping the falling weight onto a fluid pressure cylinder rod for adjusting a damping force of an impact load;
Measuring the displacement of the test pile due to an impact load applied to the test pile through the damping force adjusting fluid pressure cylinder and a load detector;
A compact loading test method comprising:

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