JPH05239819A - Standard intrusion testing device for soil - Google Patents

Abstract

PURPOSE:To enable an N value to be efficiently measured at high precision by applying strike to the upper end section of a rod with a hammer, via a hammer bearing set at the lower end section of a hydraulic cylinder. CONSTITUTION:A hammer bearing 15 set at the lower end section of a hydraulic cylinder 9 is mounted on the upper end section of a rod 51 jointed to a sampler 52. After that, in a state that a hammer 25 is retained with a hammer retaining device 17, the cylinder 9 is extended, and the retainer is moved upward together with the hammer 25, and when it moved up to a specified position, then the hammer 25 is released to be freely dropped. Then, by the dropped hammer 25, strike is applied to the upper end section of the rod 51 via the hammer bearing 15, and the sampler 52 is intruded into soil. In this case, the cylinder 9 itself to be progressively intruded is gradually moved downward, but the dropping distance of the hammer 25 is set by the stroke of the cylinder 9, and a constant distance is always kept.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test device used for performing a standard soil penetration test defined in JIS A1219.

[0002]

2. Description of the Related Art JIS A12 is a test method for knowing the relative values of hardness and softness of soil in an in-situ position.
There is a standard soil penetration test method specified in No. 19. In this method, a hammer having a weight of 63.5 kgf is freely dropped by 75 cm, and the number of impacts N required to drive the standard penetration test sampler by 30 cm is obtained. The method conventionally used as a free fall method of a hammer in this test is to reach a predetermined height by hanging a hammer chain on a tonbin-shaped device and lifting it with a hoisting wire of a boring machine. It is a method of dropping a hammer by pulling another wire attached to an instrument. In this case, the position where the hammer is dropped is determined by the mark attached to the guide rod or the like. Although this method is said to have a high accuracy in the dropping operation, it is inefficient because it is inefficient.

In addition to the above-mentioned method of using a tonbin tool,
There is also a method of using the ring machine. In this method, the hammer is wound up to a predetermined position by a rope by utilizing the rotation and friction of the pulley, and the roll is rolled at that position.
In this method, the hammer is dropped by ejecting the hammer in a forward arc. It is said that this method has low reliability because it is difficult to secure a predetermined height due to the friction of the rope and there is a large variation due to the skill and experience of the operator.
Most used because it is easy to operate and efficient.

As a further different method, when the hoisting drum is manually operated, the attaching / detaching device (three-claw spring type) attached to the upper end of the wire is fitted to the hammer and wound up to a predetermined position. There is a method of opening the nail of the attachment / detachment device and dropping the hammer. This method is gradually becoming popular because of its relatively high accuracy, but when the guide rod is set up vertically in the bored hole, there is the problem that it will come into contact with the gear of the boring machine, and pre-strike etc. Therefore, there is a problem that the attachment / detachment device is not in good condition, and variations in falling are likely to occur. In addition to these, for example, a method using a wire winch and an electromagnetic clutch (Japanese Patent Laid-Open No. 17923/1993).
No. 5), a method using a Geneva drive vehicle and an electromagnet (Japanese Patent Laid-Open No. 1-147364), but various methods have been tried, but none of them have good working efficiency and high accuracy.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a test apparatus which can measure the above N value with high accuracy and efficiency.

[0006]

In order to solve the above problems, the present invention adopts the following constitution. That is, the soil standard penetration test apparatus according to the present invention is provided with a hammer that freely falls in a predetermined section and hits a sampler, and is erected up and down along a drop passage of the hammer and is provided at a lower end portion. Is equipped with a cylinder provided with a hammer receiver against which a dropped hammer abuts, and a hammer holding device which is attached to the upper end of the cylinder and moves up and down by expansion and contraction of the cylinder. The hammer holding device holds the hammer. It is characterized in that it has a releasing means for releasing the hammer at the upper end portion of its ascending / descending stroke.

[0007]

The hammer receiver provided at the lower end of the cylinder is placed on the upper end of the rod connected to the sampler,
With the hammer held by the hammer holder, the cylinder is extended to raise the holder together with the hammer. When it reaches the specified position, release the hammer and let it fall freely. The dropped hammer hits the upper end portion of the rod through the hammer receiver to allow the sampler to penetrate into the soil. Although the cylinder itself gradually descends as the penetration progresses, the drop distance of the hammer can be set by the stroke of the cylinder, so that a constant distance can always be maintained. At the start of the test, the height of the upper end is high because the sampler has not penetrated, but in this case, by lifting the cylinder itself, slide the hammer's falling stroke upwards and drive it. Can start.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings will be described below. The figure shows an embodiment of the present invention. In this standard penetration test apparatus 1, a steering handle 4 is provided at a rear end of a traveling vehicle body 3 having a crawler type traveling apparatus 2, and a front end is provided. A column 5 is erected on the section. A pair of left and right guide rods 7, 7 parallel to the pillar are supported on the pillar 5.
A hydraulic cylinder 9, which is an elevating device, is provided between these two guide rods. The lower end of the cylinder tube 9a of the hydraulic cylinder 9 is fixed to the base 10. The base 10 is attached to the guide rods 7, 7 so as to be able to move up and down by a guide tool such as a roller 11 ..., and is supported at its lower end position by a stopper 13 provided on the vehicle body. ing.

A front projection 10a is provided at the lower end of the hydraulic cylinder 9 so as to project forward, and a hammer receiver 15 is attached thereto. A bracket 16 is fixed to the upper end of the piston rod 9b of the hydraulic cylinder 9, and a hammer holding device 17 is attached to the bracket. The board 17a of the hammer holding device 17 is a roller 1
.. are attached to the guide rods 7, 7 so as to be able to move up and down, and a small hydraulic cylinder 20 also serving as a hammer releasing means is attached downward to the base plate. A hook 21 for holding a hammer is rotatably attached to the board 17a by a pin 21a. A piston rod of the hydraulic cylinder 20 is pivotally attached to an intermediate portion of the hook 21.

The front protrusion 10a of the base 10 is
A pair of left and right hammer guide rods 22, 22 are provided upright. A hammer 25 having a total weight of 63.5 kgf is vertically slidably attached to the hammer guide rods 22, 22 via bushes 26, .... A handle 27 with which the hook 21 is engaged is provided at the upper end of the hammer 25, and a wire 31 is connected to the handle 27. On the other hand, a wire bracket 29 is provided on the upper portion of the column 5, and the measurement wire 31 having one end thereof connected to the hammer 25 is provided on the wire bracket 2.
9 is pulled out through the pulley 30.

The vehicle body 3 has a hydraulic unit 3 having a hydraulic pump, an electromagnetic valve, etc., which uses an electric motor 35 as a power source.
7. An engine 39 that serves as a power source for traveling and a measurement control device 40 are mounted. The measurement control device 40 is provided with a rotary encoder 42 to which the measurement wire 31 is connected via guide rollers 41, ..., and can electrically detect the movement amount of the wire. It has become.
FIG. 5 shows the configuration of this measurement control device, which includes limit switches 43 and 44 for detecting the upper limit position and the lower limit position of the lifting and lowering stroke of the hammer holding device 17, and the output of the rotary encoder 42. Is input to the CPU 45, and an opening / closing signal is output from the CPU to the hydraulic valves 46 and 47 for operating the hydraulic cylinders 9 and 20. From the movement amount of the wire detected by the rotary encoder 42, C
The relationship between the cumulative amount of penetration of the sampler and the number of hits and the N value are calculated by the PU 45, displayed on the display unit 48, and printed out by the printer 49. These series of operations are automatically performed according to the procedure stored in the ROM 50.

When the test apparatus 1 is used, as shown in FIG. 1, a boring hole for testing is excavated to a required depth, and a sampler 52 connected to a rod 51 is lowered to the bottom of the hole. A knocking head 54 is attached to the upper end of the rod by a rod coupling 53. 5 in the figure
5 is a protective tube for the boring hole. The vehicle body 3 is moved, the hammer receiver 15 is mounted on the knocking head 54, and the hammer-2 is held by the hook 21 of the hammer holding device 17.
5 is hung, and the hydraulic cylinder 9 is extended. At this time, the hydraulic cylinder 20 is in an expanded state. As a result, when the hammer 25 is lifted by 75 cm and reaches the upper limit position of the stroke, the limit switch 4
3 detects this and contracts the hydraulic cylinder 20. Then, since the hook 21 rotates counterclockwise in FIG. 2,
The hammer 25 is released from the handle 27, the hammer is released, and the hammer 25 freely falls along the guide rod 22.
The knocking head 54 is hit through the receiver 15. This impact causes the sampler 52 to penetrate into the soil.

When one impact is completed, the lifting hydraulic cylinder 9 contracts and the hammer holding device 17 descends, and the hydraulic cylinder 20 extends at the lower limit of its stroke to expand the hammer-2.
The handle 27 of No. 5 is engaged. In this state, the hydraulic cylinder 9
Extends and raises the hammer-25 to the upper limit position again,
The same batting operation as above is repeated. As the driving progresses, the sampler 52 descends together with the rod 51, the knocking head 54, etc., so that the hammer receiver 15 mounted on the knocking head also gradually descends together with the hydraulic cylinder 9, and the hammer strokes. The whole slides down.

At the end of the test, the knocking head 54 is at a low position, and therefore the hammer receiving position is also low. Therefore, at the start of the next test, it is necessary to lift the hammer receiver and the hammer to some extent. For this purpose, as shown in FIG.
In the extended state, the upper end of the piston rod 9b may be fixed to the column 5 by a suitable fixing means such as a pin 60 and the hydraulic cylinder 9 may be contracted. In this state, since the tip end portion of the piston rod is fixed, the cylinder tube 9a side is lifted, and the hammer receiver 15 integrated with the cylinder tube 9a side is lifted.
Also rises. In this state, the vehicle body is moved, the hammer receiver is positioned immediately above the knocking head 54 set at the next test location, and the hydraulic cylinder 9 is extended. Then, the cylinder tube 9a descends and the hammer receiver 15 is placed on the knocking head 54, so that the piston rod 9b is released from the fixation and the test is performed in the same procedure as described above.

In the above embodiment, the test apparatus is mounted on the traveling vehicle body together with the measurement control apparatus, but it is not always mounted on the vehicle body, and as shown in FIG. 7, the hydraulic cylinder 9 is mounted on the support frame 61 on the ground. It may be supported.

[0016]

As is apparent from the above description, according to the soil standard penetration test apparatus of the present invention, the free fall distance of the hammer is mechanically set, so that the variation occurs depending on the operator. Absent. Further, since the hammer is lifted and released by the hammer holding device attached to the hydraulic cylinder, no labor is required and workability is good. Therefore, it has become possible to efficiently perform a highly accurate standard penetration test.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part thereof.

FIG. 3 is a plan view of a main part.

FIG. 4 is a front view of a main part.

FIG. 5 is a block diagram of a measurement control device.

FIG. 6 is an explanatory diagram when a hammer is lifted.

FIG. 7 is an explanatory diagram of another embodiment.

[Explanation of Codes] 1 Standard Penetration Test Device 2 Traveling Device 3 Car Body 4 Handle 5 Strut 9 Hydraulic Cylinder 15 Hammer Receiver 17 Hammer Holding Device 20 Hydraulic Cylinder (Release Means) 25 Hammer 31 Wire 40 Measurement Control Device

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 6, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The front protrusion 10a of the base 10 has a
A pair of left and right hammer guide rods 22, 22 are provided upright. A hammer 25 having a total weight of 63.5 kgf is attached to the hammer guide rods 22 and 22 slidably in the vertical direction via bushes 26, .... At the upper end of the hammer 25, grip 27 is found provided that the hook 21 is engaged. On the other hand, a wire bracket 29 is provided on the upper part of the column 5, and one end of the wire bracket 29 is
The measurement wire 31 connected to the hammer receiver 15 is pulled out via the pulley 30 of the wire bracket 29.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

When using the test apparatus 1, as shown in FIG. 1, a boring hole for testing is drilled to a required depth, and a sampler 52 connected to a rod 51 is lowered to the bottom of the hole. A knocking head 54 is attached to the upper end of the rod by a rod coupling 53. 5 in the figure
Reference numeral 5 is a protection tube for the boring hole. The vehicle body 3 is moved, the hammer receiver 15 is mounted on the knocking head 54, and the hammer 2 is held by the hook 21 of the hammer holding device 17.
5 is hung, and the hydraulic cylinder 9 is extended. At this time, the hydraulic cylinder 20 is in an expanded state. As a result, when the hammer 25 is lifted by 75 cm and reaches the upper limit position of its stroke, the limit switch 43
Detects this and causes the hydraulic cylinder 20 to contract. Then, since the hook 21 rotates counterclockwise in FIG. 2, the hook 21 is disengaged from the handle 27 of the hammer 25, the hammer is released, and the hammer freely falls along the guide rod 22 and the knocking head 54 passes through the hammer receiver 15. Hit. This impact causes the sampler 52 to penetrate into the soil.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (1)

[Claims] 1. A hammer for free fall in a predetermined section to hit a sampler, and a hammer vertically movably installed along a drop passage of the hammer, the lower end of which is in contact with the dropped hammer. A cylinder provided with a receiver, and a hammer holding device which is attached to the upper end of the cylinder and moves up and down by expansion and contraction of the cylinder, the hammer holding device having the hammer held by the hammer at the upper end of its ascending / descending stroke. A standard penetration test device for soil, which has a releasing means for releasing the soil.