JPH086306B2 - Measuring device for N value in soil standard penetration test - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an N value measuring device in a standard soil penetration test.

[0002]

2. Description of the Related Art The most important thing in a standard soil penetration test is to accurately measure the N value based on the JIS standard. As a generally used measuring method, a guide rod in which a knocking head is fitted is connected to a boring rod in a boring machine, and the other end of the hoisting rope is attached to the weight that moves up and down along the guide rod. It is wound on a winding drum fixed on a boring machine, and the weight is hung up along the guide rod along the guide rod to a specified height by visual observation, and the winding line wound on the winding drum is also wound. Rewind from the take-up drum, let the above-mentioned weight fall freely along the guide rod, and hit the knocking head mounted on the guide rod to penetrate the boring rod into the ground, The penetration number is measured every 10 cm, and this measurement is performed 3 times to obtain a total of 30 c.
This is a method of recording the total number of hits as an N value for the underground penetration amount of m.

[0003]

However, in reality, the hoisting rope connected to the weight is wound around the winding drum of the boring machine, and the hoisting rope is lifted at the time when the weight is visually hung up to a prescribed height. Since the weight was rewound from the winding drum and the weight was allowed to fall freely, the hoisting and unwinding of the hoisting rope was different for each worker.
A time difference occurs, and the impact pitch of the weight with respect to the knocking head lacks uniformity.

Therefore, it is impossible to obtain an accurate N value according to the theoretically determined standard from the correlation between the impact pitch of the weight and the penetration amount of the boring rod. The present invention has been proposed in view of the above problems of the prior art, and its object is to measure the N value in a standard soil penetration test automatically and accurately. The point is to provide a device.

[0005]

In order to achieve the above object, an apparatus for measuring an N value in a soil standard penetration test according to the present invention is mounted on a guide rod mounted on a boring machine and equipped with a knocking head. A guide rod for measuring an N value in a soil standard penetration test, in which a weight is fitted so as to be able to move up and down, and the other end of a lifting rope connected to the same weight at one end is wound on a winding drum. A weight upper limit stop head equipped with a degaussing limit switch is attached to the measuring rod, and a measuring rod formed by engraving measuring spots at predetermined intervals is attached to the measuring rod, and the measuring spot is attached to the outer circumference of the measuring rod. A sensor spot holding a constant detection interval is mounted, and a transparent cylindrical sensor head fixed to the upper end of the sleeve of the boring machine is fitted to the measuring spot and the sensor. When spot and reaches a certain detection distance, the electromagnetic clutch brake unit attached to the boring machine by the reaction of the proximity sensor occurring during the Kenshaku spots and sensor spot is excited,
The weight is automatically raised and lowered repeatedly along the guide rod, and the knocking head mounted on the guide rod is hit to display the number of hits until the boring rod reaches a specified penetration amount. The control device is installed between the power source and the electromagnetic clutch brake unit and the proximity sensor device.

[0006]

Since the present invention is constructed as described above,
Normally, the weight is located on the knocking head attached to the guide rod, the measuring rod is fitted in the cylinder of the sensor head, and the measuring spot and the sensor spot are at positions where the detection distance is maintained. It has stopped.

When the electric power is input to the control device, the control device is actuated, and the measuring shaft and the sensor spot are driven by the driving device mounted on the boring machine due to the sensor reaction. And an electromagnetic clutch brake unit interposed between the rotary shaft of the winding drum and the rotary shaft of the winding drum is excited, the rotary shaft of the winding drum is connected to the input device to drive the rotary shaft, and one end of the weight is attached. Since the hoisting rope equipped with is taken up by the take-up drum, the weight is lifted up to the weight upper limit stop head along the guide rod and abuts against the limit switch mounted on the stop head. By operating the limit switch to demagnetize the electromagnetic clutch brake unit, the connection between the input device and the winding drum is released and the weight is connected to the weight. The hoisting line is rotated by the self-weight of the same weight to reversely rotate the winding drum to rewind the hoisting line, so that the above-mentioned weight freely falls along the guide rod and remains on the rod. Hit the knocking head and let the bowling rod penetrate into the ground.

In the spring mounted on the limit switch, the weight is released from the limit switch, and at the same time, the spring is released from the contact with the weight and returns to its original position. Are connected to each other, the electromagnetic clutch brake unit is re-excited, the winding drum winds the hoisting rope, and the weight is moved up along the guide rod.

After that, the weight is automatically repeatedly moved up and down as described above. The amount of penetration of the boring rod into the ground is 10 times as one cycle, and the total number of hits by which the weight has knocked the knocking head is measured as an N value three times in total, and the total weight is 30 cm. As described above, since the device of the present invention is operated accurately for each penetration amount of 10 cm, the transparent cylindrical sensor head fitted with the sensor spot is fitted to the boring rod inserted into the boring machine. The boring rod penetrates into the ground by hitting the weight and the measuring rod connected to the boring rod is integrated with the boring rod. And the measuring spot engraved on the measuring rod reaches within a certain detection interval corresponding to the sensor spot fitted on the sensor head fixed to the outer circumference of the measuring rod. Then, the electromagnetic clutch brake unit is excited, and as described above, the weight operates to automatically strike the knocking head at a uniform striking pitch. .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. A is a boring machine, and B is a tripod turret which is used for both boring work and N value measurement. D is a winding drum, and one end of a hoisting cable F, which is suspended on a pulley E mounted on the triangular tower B, is wound. One end of the hoisting cable F is connected to the weight W, and the other end is wound around the winding drum D via the pulley E.

Reference numeral G denotes a guide rod. A knocking head N is fitted to the lower end of the rod G, and a measuring rod K is joined to the lower end of the knocking head N. The boring rod L is inserted into the sleeve at the upper end of the boring machine A, and the transparent cylindrical sensor head S fitted to the rod L is fixed to the boring machine A. The sensor head S has a sensor spot S _{1 serving as a} transmitting portion screwed on.

K is a measuring rod and the boring rod L
The measuring rod K, which is connected to the upper side and is vertically inserted into the cylindrical sensor head S, has a measuring spot K ₁ ,
K ₂ and K ₃ are engraved. FIG. 2 shows an electromagnetic clutch / brake unit U for automatically operating the lifting and lowering of the weight W.
(See FIG. 1) and a limit switch R that also serves to measure the number N of taps of the weight W with respect to the knocking head N, and a sensor device that automatically regulates the standard amount of penetration of the boring rod L into the ground. Control device 2 between power supply 1
An electric circuit diagram configured by interposing is shown. A spring (not shown) for connecting and disconnecting an electric circuit is mounted on the limit switch R, and when the weight W collides with the switch R, the spring is pressed to demagnetize the electromagnetic clutch brake. When W is separated from the switch R, the pressing force by the weight is released, the spring returns to its original position, and the electromagnetic brake unit is excited.

Since the illustrated embodiment is constructed as described above, when the drive wheel 9 is driven by the drive device provided in the boring machine A, the drive wheel 9 and the auxiliary wheel connected through the endless chain 6 are connected. The driving wheel 10 is driven and rotates. Thus, the weight W is always seated on the knocking head N, but
Is excited, the input shaft device 7 fixed to the driven wheel 10 and the winding drum D are connected, and the winding drum D rotates integrally with the driven wheel 10 to wind up the hoisting cable F. , The weight W is raised along the guide rod G.

When the weight W rises and strikes against the limit switch R mounted on the weight rise stop head T fixed to the guide rod G, the limit switch R operates to operate the electromagnetic clutch brake unit U. Degaussing, disconnecting the connection between the input device 7 and the rotary shaft 8 of the winding drum D, and as a result, the weight W freely falls along the guide rod G while unwinding the hoisting cable F by its own weight and knocking head. Hit N to penetrate bowling rod L into the ground.

When the weight W is disengaged from the limit switch R, the spring mounted on the limit switch R is released from the pressing force of the weight W and returns to its original position, and the electromagnetic clutch is released. The brake unit U is excited, the input device 7 and the rotary shaft 8 fixed to the winding drum D are connected, the winding drum D rotates, and the weight W causes the guide rod G to rotate as described above. And then the weight W repeats ascending and descending in the same manner. Hereinafter, as described above, the weight W freely falls from the height defined by the ascending head T and knocks the knocking head N at a uniform pitch to penetrate the boring rod L into the ground.

When the weight W is seated on the knocking head N, the sensor head S equipped with the sensor spot S ₁ is fixed to the upper sleep of the boring machine A, and the sensor head S is mounted in the cylinder of the sensor head S. A measuring rod K is freely inserted in and up and down, and measuring rods K are provided with measuring spots K ₁ , K ₂ and K ₃ . The measuring spots K _{1 to} K ₃ and the sensor spot S ₁ are at the detection distance, and the power supply 1 excites the electromagnetic clutch / brake unit U via the control device 2 and the sensor device to wind the coil as described above. Rotating shaft 8 directly connected to drum D and input device 7
And the winding drum D winds the hoisting rope F, and the weight W
Rises along the guide rod G. Thereafter, the weight W continues to ascend, falls freely from the height defined by the ascending stop head T, and knocks at the knocking head N at a uniform striking pitch.
The boring rod L is penetrated into the ground by tapping.

Thus, the measuring spots K ₁ , K ₂ , K engraved on the measuring rod K connected to the boring rod L are formed.
₃ is pushed down together with the boring rod L and sequentially positioned at the sensor detection distance, but the reaction causes the electric circuit 5 to be interrupted by the control device 2 so that the weight W continues to operate and boring When the rod L reaches the standard penetration amount of 10 cm, the measuring spot K ₁ engraved on the measuring rod K subordinate to the rod L reaches the detection distance with respect to the sensor spot S ₁ , and thus the boring is performed. The limit switch R reads the number of hits of the knocking head N by the weight W while the rod L penetrates 10 cm, and digitally displays it on the counter 3 via the control device 2.

The above-described operation is repeated thereafter, and the weight W freely falls from the height defined by the ascending / descending head T, taps the knocking head N at a uniform striking pitch, and causes the boring rod L to penetrate into the ground. In the standard soil penetration test, 10 cm is set as one cycle, and a total of 3 times, 30 cm
It is possible to automatically and accurately measure the total number of hits of the knocking head N by the weight W until it penetrates, as an N value.

[0019]

According to the present invention, as described above, in the N value measuring device in the penetration test of the standard soil, the lifting and lowering of the weight, which is fitted up and down on the guide rod connected to the boring rod. An electromagnetic clutch brake unit is interposed between a rotary shaft of the rope winding drum and an input shaft that is driven and rotated by a drive device mounted on the boring machine, and a weight rising stop head mounted on the guide rod. A demagnetization limit switch was installed in parallel with the excitation of the electromagnetic clutch brake unit, and the amount of soil penetrating into the front boring rod was engraved on the measuring rod to operate the weight at a specified penetration depth. By regulating the operation of the weight by the proximity sensor distance between the measuring spot and the sensor spot screwed to the sensor head, the weight defines the knocking head. Automatically and accurately measure the N-value in the standard penetration test soil by repeated tapping uniform pitch from the height that is intended for and displays the counter.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an N value measuring device in a standard soil penetration test according to the present invention.

FIG. 2 is an operating circuit diagram of the device of the present invention.

[Explanation of symbols]

A Boring Machine B Tripod Turret D Winding Drum E Pulley F Elevating Line G Guide Rod K Measuring Rod L Boring Rod M Motor N Knocking Head R Limit Switch S Sensor Head S ₁ Sensor Spot T Weight Upper Limit Stop Head U Electromagnetic Clutch Brake Unit K ₁ , K ₂ , K ₃ Measuring spot W Weight 1 Power supply 2 Control device 3 Counter panel 4 Relay box 5 Electric circuit 6 Endless chain 7 Input device 8 Rotating shaft 9 Drive wheel 10 Driven wheel

Claims (1)

[Claims] 1. A boring machine is equipped with a knocking head, a weight is fitted to a guide rod so that the weight can be moved up and down, and the other end of a hoisting line whose one end is connected to the weight is used as a winding drum. In an N value measuring device in a standard penetration test of wound soil, a weight upper limit stop head equipped with a degaussing limit switch is attached to the guide rod, and measuring spots are formed at predetermined intervals. A transparent cylindrical sensor fixed to the upper end of the sleeve of the boring machine by attaching a measuring rod to the measuring rod, mounting a sensor spot on the outer periphery of the measuring rod that maintains a constant detection distance from the measuring spot. When the head is fitted and the measuring spot and the sensor spot reach a certain detection distance, a proximity sensor that occurs between the measuring spot and the sensor spot. The electromagnetic clutch brake unit mounted on the boring machine is excited by the reaction of the sir, and the weight is automatically repeatedly moved up and down along the guide rod to repeatedly operate the knocking head mounted on the guide rod. Soil characterized in that a control device for displaying the number of hits until the drilling rod reaches a specified penetration amount is inserted between a power source and an electromagnetic clutch brake unit as well as a proximity sensor device. Measuring device for N value in standard penetration test.