JPH10153099A - Strength measuring method and device for sprayed concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily measure the strength of unhardened sprayed concrete at a site by driving a drive member with nearly constant force, and measuring the strength of the concrete based on the depth of the portion intruded into the concrete. SOLUTION: When a plunger 15 screwed at the tip of a connecting shaft 12 is thrust backward, a moving disk 11 is moved backward, and a strike spring 17 is gradually spread. When a lock pin 14 pushes a hook pawl 21, a hook member 20 is rotated CCW against the action of a holding spring 22, and the hook pawl 21 is locked on the lock pin 14. When a butt member 8 is put on the sprayed concrete to be measured and a trigger 26 is pulled, the trigger 26 is turned CW centering on a shaft 66, the tip pushes an action disk 23 forward, and the action disk 23 pushes the hook member 20. The hook member 20 is turned CCW centering on a pin 19, the hook pawl is released from the lock pin 14, the strike spring 17 strikes a moving member 10, and the plunger 19 is driven into the sprayed concrete. The strength of the concrete can be easily measured based on the intruded depth of the plunger 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the strength of shot concrete for measuring the strength of concrete sprayed on rock or the like.

[0002]

2. Description of the Related Art Conventionally, the measurement of the early strength of shotcrete has been conducted, for example, on concrete sprayed on the surface of an excavated tunnel. By knowing the strength of the sprayed concrete at an early stage, it is possible to change the conditions of the concrete to be sprayed thereafter. In other words, it is known whether the ratio of the quick setting agent mixed in the sprayed concrete is appropriate, and if it is appropriate, the subsequent spraying can be performed without changing the conditions. Spraying can be performed by correcting the deviation.

[0003] As described above, the measurement of the early strength of shotcrete is important for the quality control of concrete at the site, and has conventionally been measured by a pull-out test. In this pull-out test, as shown in FIG. 5, an appropriate number of molds 50 to which pins 51 are fixed are prepared, and concrete C to be tested is sprayed into the molds 50 so that the pins 51 are embedded in the molds 50. After a predetermined time, the pin 51 was pulled out from the opposite side. At this time, the shear strength was determined from the pulling force P and the shear plane A of the breaking cone, and this was converted into compressive strength.

[0004]

However, the pull-out test has the following problems. (1) The pull-out test cannot be performed until several hours have elapsed since the concrete was sprayed. That is, inspection cannot be performed unless concrete hardens to some extent. (2) Since the pull-out test is performed using only a sample, the conditions may be different from those of concrete sprayed on actual rock.

[0005] Therefore, there is a demand for an apparatus capable of easily measuring concrete in the range of a young material age which has not passed since spraying at a young age, but it has not yet appeared.

The present invention has been made in view of the above circumstances, and provides a method and an apparatus for measuring the strength of shotcrete that can easily measure the strength of shotcrete that has not yet completely hardened early and on site. It is an object.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for measuring the strength of shotcrete, which measures the strength of concrete sprayed on rock or the like.
It is necessary to measure the strength of concrete from the depth of the part of the driven member that has penetrated into the concrete with almost constant force applied to the concrete of the young age sprayed on the bedrock etc. Features.

Further, in order to achieve the above object, the present invention provides a shot concrete strength measuring device for measuring the strength of concrete sprayed on a rock or the like, comprising: a movable member having a driving member fixed at a tip thereof; A guide member for slidably guiding the movable member, an elastic member for driving the driving member through the movable member with a substantially constant elastic force, and a stop position of the movable member when the driving member is driven into shotcrete. Display means for displaying the depth of the portion where the driving member has entered the concrete.

The present invention provides a pointer provided on the movable member, the display unit provided at a position where the pointer stops when the driving member is driven into shotcrete, a display unit provided at a position where the pointer stops. It is effective if a cover member is provided to cover the display unit, and the cover member is rotatably mounted on the measurement device main body and a mirror is provided on a surface facing the display unit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory sectional view showing an example of a shot concrete strength measuring apparatus according to the present invention.

Referring to FIG. 1, the strength measuring device includes a device body 1 formed in a cylindrical shape. The device body 1 has a first cylinder 2 as a guide member and a diameter larger than the first cylinder 2 by a thickness. It has a second cylinder 3 formed, and a part of the first cylinder 2 is inserted into the second cylinder 3 to be connected and fixed so that the axes of both cylinders coincide. A movable member 10 is fitted in the first cylinder 2 so as to be movable in the axial direction, and the movable member 10 is provided with a movable disk 11 having a certain width. The diameter of the movable disk 11 is formed slightly smaller than the inner diameter of the first cylinder 2. A connecting shaft 12 is fixed to the side of the distal end of the movable disk 11, and a spring receiving ring 13 is fixed to the connecting shaft 12 at an intermediate position between the connecting shaft 12 and a plunger as a driving member. A screw hole for screwing 15 is formed. A locking pin 14 is provided on a rear end side surface of the movable disk 11 to lock a hooking claw 21 of a hooking member 20 described later.

A spring retaining ring 16 and a distal end ring 4 are fixed to the distal end side of the first cylinder 2, and a hole through which a plunger 15 passes is formed in the spring retaining ring 16 and the distal end ring 4. A striking spring 17 as an elastic member is fitted between the spring receiving ring 13 and the spring holding ring 16, and both ends of the striking spring 17 are fixed to the spring receiving ring 13 and the spring holding ring 16, respectively. In addition,
The impact spring 17 of the present embodiment is a coil spring having a considerably strong spring force.

A disk 18 is fixed to the rear end of the first cylinder 2, and a hooking member 20 is rotatably mounted on the disk 18 via a pin 19. In this case, the hooking member 20 is a substantially U-shaped plate-like member having a hooking claw 21 formed at the tip, inserted into a groove (not shown) formed in the disk 18, and Supported. Further, a holding spring 22 is fitted near the rear end side of the hook member 20 between the hook member 20 and the disk 18, and the hook claw 21 of the hook member 20 always locks the locking pin 14 with respect to the hook member 20. The urging of the habit of turning.

An operating disk 23 is fitted in the second cylinder 3 so as to be movable in the axial direction, and two upper and lower guide shafts 24 are fixed to a surface of the operating disk 23 facing the disk 18. ing. The guide shaft 24 is movably fitted into a through hole (not shown) formed in the disk 18, and
Is provided with a stopper (not shown) for preventing the disk 18 from coming off. A compression spring 25 is fitted between the disk 18 and the working disk 23 so as to wind the guide shaft 24. This compression spring 2
Numeral 5 urges the working disk 23 with an elastic force for keeping the distance between the disk 18 and the working disk 23 constant.

At the lower part of the second cylinder 3, a mounting plate 5
A trigger 26 is rotatably supported on the mounting plate 5 via a shaft 6. The distal end of the trigger 26 extends to a position where it contacts the operating disk 23. By pulling the trigger 26 in the direction of the arrow, the trigger 26 rotates clockwise through the shaft 6, and the distal end of the operating disk 2
3 is configured to be pushed rightward in FIG. Reference numeral 7 denotes a grip that the operator grips during measurement.

As shown in FIG. 2, the first cylinder 2 has
A display window 30 as a display unit covered with a transparent plastic or the like is formed on the upper part thereof, and the display window 30 is provided with a scale or the like as clearly shown in FIG. On the upper part of the display window 30, a cover member 3 formed to have a size to cover the entire surface thereof.
1 is mounted so as to be rotatable about a pin 32,
The cover member 31 has a mirror 3 on its surface facing the display window 30.
3 are provided. A pointer 34 is written on the upper part of the movable disk 11. Note that the display window 30, the cover member 31, the mirror 33, and the pointer 34 constitute display means of the present example.

At the tip end of the tip ring 4, two striking members 8 of a predetermined length are provided, and the measurement is performed with the striking members 8 struck against shotcrete. Next, a measuring method of the shotcrete with the above-described configuration using the strength measuring device will be described.

First, the plunger 1 is attached to the tip of the connecting shaft 12.
5 is screwed and pushed backward by a pushing member (not shown), and at this time, the movable disk 11 is lowered backward, so that the impact spring 17 is gradually expanded. And movable disk 1
When the first locking pin 14 reaches the hooking claw 21 of the hooking member 20 and presses it, the hooking member 20 is moved to the holding spring 2.
When the hook 21 is moved in the counterclockwise direction in FIG. 1 against the action of FIG.
2, the measuring device is locked by the locking pin 14, and the measuring device is in the state of FIG. In this state, the distal end side of the apparatus main body 1 is supported by one hand, the other hand is gripped by the grip 7, and the shot concrete C butting member 8 to be measured is abutted. Here, when the trigger 26 is pulled, the trigger 26 rotates clockwise about the shaft 6 and the tip thereof is
Press to the right in FIG. At this time, the working disk 23 moves rightward against the action of the compression spring 25 and pushes the hook member 20. When the hooking member 20 rotates counterclockwise about the pin 19, the hooking claw 21 is rotated.
Is disengaged from the locking pin 14 and the movable member 10 is
Is fired toward shotcrete C by spring force.

As described above, when the movable member 10 is driven out by the strong spring force of the impact spring 17, the plunger 15 is driven into the shotcrete C as shown in FIG. At this time, the strength of the shotcrete C can be measured from the depth at which the plunger 15 is driven. In this case, assuming that the depth of the plunger 15 driven into the shotcrete C in FIG. 3 is a, the abutting member is arranged such that the length from the left end of the display window 30 to the position where the pointer 34 stops is also a. The length of 8 and the positions of the pointer 34 and the display window 30 are determined. That is, when the plunger 15 stops on the surface of the shotcrete C, the pointer 34 stops at the left end of the display window 30. Further, if the relationship implanted in that the depth and intensity of the plunger 15 is driven plunger 15 is many centimeters from previously conducted experiments data using the same apparatus in Shotcrete C, the strength of roughly what kg / cm ² Can be measured.

The position of the pointer 34 is visually recognized through the mirror 33. That is, before driving the plunger 15, the measurement is performed after the cover member 31 is set up to a position where the display window 30 reflects the mirror 33 and can be clearly seen. By doing so, the operator does not need to look into the display window 30, so that the posture during the operation is easy, and the operator can move away from the shotcrete C even a little, thereby reducing the danger from falling concrete and the like. Is done. In addition, since the cover member 31 can cover the display window 30 when not in use, there is an advantage that the display window 30 is prevented from being soiled. The tunnel excavation site is in an environment that is easily contaminated with dust and the like, and is advantageous as a device used on the site.

The apparatus for measuring the strength of shotcrete according to the present invention is constructed as described above, and the strength of shotcast concrete C having a young material age is determined by a novel measuring method in which the plunger 15 is driven with a constant force of the impact spring 17. It can be measured on site. Although it is difficult for the strength measuring device of the present invention to measure a value of an accurate strength, it can be easily known if the strength of the sprayed concrete is equal to or higher than a predetermined value. Therefore, it is very useful as a measurement for determining whether or not to proceed to the next operation.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but can be variously modified. For example, in the above example, the apparatus main body 1 is constituted by the first cylinder 2 and the second cylinder 3, but the apparatus main body 1 may be constituted by one cylinder. Further, the apparatus main body 1 is not limited to a cylinder as long as it is cylindrical.

In the above example, the plunger 15 has a thin shaft, but the diameter of the shaft of the plunger 15 may be arbitrary. For example, as shown in FIG. A large plunger 15 may be used. Also,
The plunger 15 may have a shape that is not sharpened. In this case, data on the relationship between the driving depth and the strength of each plunger 15 may be prepared. In addition, the plunger 15 having a large diameter or a flat tip can be used for measuring soft concrete, and the plunger 15 having a small diameter and a sharp tip can be used for measuring slightly hardened concrete. .

[0024]

According to the present invention, it is possible to measure the shotcrete C having a low strength at the site. Moreover,
Since it is a pure machine, even if the environment of the place of use such as a tunnel excavation site is bad, a failure is less likely to occur, which is advantageous.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing one example of an apparatus for measuring the strength of shotcrete according to the present invention.

FIG. 2 is a perspective view showing a state at the time of measurement of the intensity measuring device of FIG. 1;

FIG. 3 is an explanatory cross-sectional view showing a state at the time of measurement of the intensity measuring device of FIG. 1;

FIG. 4 is a side view showing a modified example of the plunger.

FIG. 5 is an explanatory diagram showing a conventional pull-out test.

[Explanation of symbols]

 2 First cylinder 10 Movable member 11 Movable cylinder 15 Plunger 17 Striking spring 26 Trigger 30 Display window 31 Cover member 34 Pointer C Shotcrete

Claims (3)

[Claims] 1. A method for measuring the strength of a shotcrete, which measures the strength of a concrete sprayed on a rock or the like, comprising: a driving member formed into a predetermined shape with a substantially constant force against concrete of a young age sprayed on a rock or the like. And measuring the strength of the concrete from the depth of the part of the driven member that has entered the concrete. 2. A blown concrete strength measuring device for measuring the strength of concrete blown on a rock or the like, comprising: a movable member having a driving member fixed at a tip thereof; and a guide member for slidably guiding the movable member. An elastic member that strikes out the driving member with a substantially constant elastic force via the movable member, and a portion where the driving member enters the concrete due to the stop position of the movable member when the driving member is driven into shotcrete. And a display means for displaying a depth. 3. The apparatus for measuring the strength of shotcrete according to claim 2, wherein the display means has a pointer provided on the movable member, and a position at which the pointer stops when the driving member is driven into the shotcrete. And a cover member that covers the display unit, and the cover member is rotatably mounted on the measurement device main body,
A concrete spraying device, wherein a mirror is provided on a surface facing the display unit.