JPH10331142A - Automatic penetration testing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance by providing impact varying means of varying the impact of a driver, having a penetration part given impact to penetrate a ground, into preset force. SOLUTION: When, during penetration test, a chain 4 is rotationally moved with a motor 6 to move a hammer 9 up, a first level sensor 22 detects a sensor dog 21 provided on the hammer 9 to cut the driving force of the motor 6. The hammer 9 is dropped by its weight, a rod 12 penetrates a ground via a knocking head 11 and an encoder 14 pulse-counts the rotating number of a wheel 13 rotated corresponding to a penetration amount to detect the penetration amount of the rod 12. When the rod 12 hits stones or a hard bed and disables itself to penetrate, the encoder 14 is detected not to pulse-count it, the operation of the sensor 22 is stopped, the position of the hammer 9 is detected by a second height sensor 23 and then the hammer 9 is positioned higher in dropping to increase its impact. In this way, ground resistance and penetration amount can be accurately measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic penetration tester for easily measuring ground strength and the like, which is carried out, for example, before construction of a house.

[0002]

2. Description of the Related Art In the construction of a house, the ground strength and the like are measured in advance so that the house can be safely constructed. This measurement knows the hardness of the soil and the degree of compaction,
This is for setting the foundation of the house. As a conventional automatic penetration tester for measuring soil strength, etc.,
Japanese Patent Application No. 58404 discloses a testing machine which strikes a penetrating portion and measures the ground strength from the amount of penetration. The automatic penetration tester is for vertically moving a driving device composed of a hammer of about 8 kg to penetrate a rod into the ground, and measuring the ground strength from the amount of penetration and the number of driving times.

[0003]

However, since the hitting force of the driving device cannot be changed with such a conventional automatic penetration tester, when the tip of the rod reaches a stratum containing many rocks and pebbles, Sometimes it was impossible to penetrate. In such a case, it was impossible to measure the bearing capacity at a deeper place. Further, in some cases, the measurement location has to be changed and the ground strength and the like must be measured again. In addition, if the impact force of the driving device is increased in advance by increasing the weight of the hammer, etc., the penetration amount becomes large in a relatively soft stratum, so that accurate measurement of the ground strength cannot be performed, and the measurement error of the ground strength is not possible. There were conflicting problems such as the occurrence of

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to make it impossible to penetrate without impairing the measuring ability such as ground strength by making the impact force of a driving device variable. It is an object of the present invention to provide an automatic penetration tester which reduces such a problem.

[0005]

According to one aspect of the present invention, there is provided an automatic penetrating tester comprising: a penetrating portion; and a driving device for striking the penetrating portion to penetrate into the ground. The machine has a striking force varying means for changing the striking force of the driving device to a predetermined force.

Here, the penetrating portion is made of a rod-shaped member, and it is preferable to sharpen the tip so that it can easily enter the ground, and the material is preferably metal. In addition, it is preferable to be able to replenish so that it can penetrate deep into the ground. The driving device drives the penetrating portion in a substantially vertical direction, and is capable of hitting a plurality of times. There are various methods of driving, such as a method of dropping a hammer and a method of forcibly applying a force to a penetration portion using a hydraulic cylinder.

[0007] As the impact force varying device, there are devices that change the hammer falling distance, give an initial speed when the hammer falls, and change the weight of the hammer. In particular, when changing the weight of the hammer, it may be performed automatically or manually.However, when changing the weight manually, for example, by adding a weight to the hammer, fixing means of the hammer and the weight, etc. Is also included in the impact force variable device. In addition, there are devices that change the impact force by controlling the hydraulic pressure of the hydraulic cylinder. When driving the penetrating part, the driving device will collide with the penetrating part, but if the kinetic energy is not conserved before and after the collision, using the law of conservation of momentum requires a more accurate impact force It is preferred.

According to a second aspect of the present invention, there is provided an automatic penetration tester according to the first aspect, wherein the driving device includes a hammer that falls at a constant acceleration, and the impact force varying device includes the hammer. The hitting force is changed by changing the falling distance of the impact. Here, the constant acceleration is preferably due to gravity because the configuration of the testing machine becomes easy. However, even if there is a friction due to the configuration of the device or a brake that operates with a constant force, it is sufficient if the device falls down at substantially equal acceleration. The hammer may be dropped at a constant acceleration by continuously applying a constant force to the hammer by some device. The hammer fall distance can be changed automatically or manually. In particular, when the drop distance of the hammer is manually changed, an index indicating the drop distance is also included in the impact force variable device.

According to a third aspect of the present invention, there is provided an automatic penetration testing machine according to the first aspect, wherein the driving device comprises a hammer, and the hitting force varying device includes a hammer inserted into a penetration portion of the hammer. The striking force is changed by changing the speed at the time of collision. Here, the hammer is one that drives a penetration part by dropping or the like to penetrate into the ground. To change the speed of the hammer at the time of collision with the penetration, the initial speed is given at the time of the fall, the hammer is dropped, the force is accelerated during the fall, and the fall speed of the hammer is controlled using the brake. And other methods.

According to a fourth aspect of the present invention, there is provided an automatic penetration tester according to the first aspect, wherein the driving device comprises a hammer, and the impact force varying device changes the weight of the hammer. Thus, the striking force is changed. Here, as an example for changing the weight, the driving device attaches a plurality of weights to the hammer and has a detachable structure, or changes the weight of the hammer according to the number of weights attached, There are things that replace the hammer itself.

[0011]

According to the construction of the automatic penetration tester according to the first aspect, when the penetration part penetrates into the ground, for example, even if it is impossible to penetrate a very hard stratum, the impact force of the driving device is reduced. By strengthening with a variable device, it can be penetrated again. After being able to penetrate, it is possible to return to the normal striking power. In the case of striking a soft stratum, a clear difference occurs in the penetration amount of the penetration portion by weakening the impact force. By reading this difference, an accurate bearing capacity can be measured.

According to the configuration of the automatic penetration tester according to the second aspect, since the hammer falls at a constant acceleration, the impact force can be changed by changing the fall distance of the hammer. For example, the falling distance of the hammer is h, the acceleration is a, the speed of the hammer immediately before hitting is v, and the initial speed is 0.
Then, it is represented by v ² = 2ah. Therefore, since the speed of the hammer changes by changing the falling distance, the hitting force of the driving device can be changed to a predetermined force.

According to the configuration of the automatic penetration tester according to the third aspect, the kinetic energy and the momentum of the hammer are changed by changing the speed at the time of collision of the hammer with the penetrating portion, so that the impact force is changed. be able to.
Here, the mass of the hammer is m, and the speed at the time of the collision of the hammer with the penetration portion is v. For example, the kinetic energy so expressed by mv ^2/2, the kinetic energy is proportional to the square of the velocity at impact. In addition, since the momentum can be represented by mv, the momentum is proportional to the speed at the time of collision. Therefore, the impact force of the driving device can be changed to a predetermined force by changing the speed at the time of the collision.

According to the configuration of the automatic penetration tester according to the fourth aspect, the kinetic energy and the momentum of the hammer are changed by changing the weight of the hammer, so that the impact force can be changed. Here, the mass of the hammer is m, and the speed at the time of the collision of the hammer with the penetration portion is v. For example, since the kinetic energy is expressed by mv ^2/2, the kinetic energy is proportional to the weight of the hammer. In addition, since the momentum can be represented by mv, it is similarly proportional to the weight. Therefore, by changing the weight of the hammer, the impact force of the driving device can be changed to a predetermined force.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Here, FIG. 1 is an explanatory view showing an automatic penetration tester of Embodiment 1 of the present invention. FIG. 2 is an explanatory view showing an automatic penetration tester according to a second embodiment of the present invention. FIG. 3 is an explanatory view showing an automatic penetration tester according to Embodiment 3 of the present invention.

[Embodiment 1] Embodiment 1 is an automatic penetration tester in which the falling distance of a hammer is changed. In the drawing, a column 1 of an automatic penetration tester is provided upright and immovably on a base 2. The base 2 is provided with an adjuster 3 that can be adjusted so that the column 1 is perpendicular to the ground. The penetrating portion is composed of the rod 12 and a slightly thicker cone loaded at the rod tip. Rod 12
Is driven into the ground by a driving device provided with a sprocket 5, a chain 4 wound around the sprocket 5, and a driving device configured to open the chain 4 at regular intervals. The amount of penetration of the rod 12
It can be measured by reading the amount of rotation of a rotating part composed of a wheel 13 provided in contact with the sensor with an encoder 14 of an angle detection type. A motor 6 is used as the driving device, and the sprocket 5 is driven by the motor 6. Also,
A clutch 7 is provided between the motor 6 and the sprocket 5. The transmission of the driving force of the motor 6 can be controlled by the connection state of the clutch 7.

The driving device includes a support 1 and a guide rod 1.
0, a hammer 9 and a knocking head 11. Guide arms 201 and 202 fixed to the column 1 so as to protrude outward, and a first height sensor 22 for detecting that the hammer 9 has risen to two predetermined height positions.
And a second height sensor 23. The height sensors 22 and 23 are sensor dogs 21 fixed to the hammer 9.
By detecting that the hammer has reached a predetermined height. In addition, both the height sensors 22 and 23 are attached to the guide rod 10 by a sensor bracket 27.
Is fixed through. Therefore, even if the rod 12 penetrates into the ground, the position of the height sensors 22 and 23 does not change. That is, the falling distance of the hammer does not increase slightly each time the penetration portion is driven. A rod 1 with a cone loaded at the tip on the lower guide arm 202
2 is vertically inserted and held, and a guide rod 10 having a knocking head 11 fixed to the lower end of the upper guide arm 201 is inserted and held, and the knocking head 11 is mounted above the rod 12. A vertically movable hammer 9 is fitted on the knocking head 11, and the hammer 9 is attached to the chain 4 via a connecting member 8 so as to be vertically movable in accordance with the movement of the chain 4. . The hammer 9 which moves the guide rod 10 up and down has a weight of 8 kg and falls about 50 cm between the upper guide arm 201 and the knocking head 11.
In the vicinity of the penetrating portion of the rod 12, the wheel 13 of the rotating portion is in contact with the guide roller 24 so as to sandwich the rod 12 therebetween.

Next, the operation of the apparatus will be described. The sprocket 5 and the chain 4 are rotated by the driving force of the motor 6, whereby the hammer 9 is raised. Hammer 9
The sensor dogs 21 fixed to the first position rise together and are detected by the first height sensor 22 at a predetermined height. When the first height sensor 22 detects the rise of the hammer 9, the driving force of the motor 6 is cut off. Then, the hammer 9 falls naturally by its own weight, and strikes the rod 12 toward the ground via the knocking head 11. At this time, the wheel 13 rotates according to the amount of penetration of the rod 12, and the amount of rotation is
By performing the pulse count at 4, the amount of penetration of the rod 12 is detected.

In some cases, the tip of the rod 12 hits a stone or a very hard stratum and cannot penetrate. In this case, the wheel 13 does not rotate and the encoder 14 does not count pulses. By detecting the state in which the pulse is not counted, it is possible to know the impossibility of penetration. In this situation, the impact force of the hammer 9 is insufficient, and it is necessary to raise the drop position of the hammer 9. Therefore, at this time, the operation of the first height sensor 22 is stopped, and the elevation of the hammer 9 is detected by the second height sensor 23 having the same function as the first height sensor 22. . In this way, the height position at which the hammer 9 falls can be increased, and the impact force can be increased. Furthermore, the penetrating state can be achieved again due to an increase in the impact force. Although two height sensors are provided, the height sensors may be further increased to increase the selection range of the drop height of the hammer 9. After the drop position of the hammer 9 is raised, if the penetration amount in one hit becomes larger than a predetermined value, the drop position of the hammer 9 is returned to the original position. As another method of changing the drop position, there is a method of detecting the amount of rise when raising the hammer 9 from the rotation amount of the wheel 13 with the encoder 14 and disengaging the clutch 7 according to the amount of rise.

Next, how to determine the ground bearing capacity will be described. First, an Ns value for determining the ground strength is calculated from the amount of penetration measured by the encoder 14 and the number of impacts. Note that the Ns value refers to the number of hits required to drive the penetrating portion 100 cm, and is given by the following equation. Ns value = (100 / penetration amount) × number of hits However, 100 cm driving means that the same stratum as the stratum at the penetrating portion is uniformly 100 cm, and the stratum having a uniform stratum is not less than 100 cm. It does not mean that. In the embodiment, the Ns value is automatically obtained for each impact, and the Ns value is (100 /
It can be obtained by one penetration. Further, by substituting the Ns value into a conversion formula obtained in advance, the ground bearing strength is calculated. However, the conversion formula is prepared according to the hammer drop distance.

[Embodiment 2] Embodiment 2 is an automatic penetration tester in which the speed at the time of collision of a hammer with a penetration portion is changed. The sprocket 5 is provided with a brake 25 that can control the rotation of the sprocket 5. The brake 25 is a powder brake containing a powder-like magnetic powder, and changes the magnetic flux generated inside by changing an externally applied voltage to control the braking force. Normally, the driving is performed in a state in which a constant braking force is applied by the brake 25, and when the impossibility of penetration is detected as described above, the braking force of the brake 25 is reduced. By doing so, the speed at the time of collision of the hammer 9 can be increased, and the impact force of the hammer 9 increases. After the impact force is increased, if the amount of penetration in one impact exceeds a predetermined value, the braking force of the brake 25 is returned to the original value so that the speed of the hammer 9 returns to the original speed. The bearing capacity can be determined in the same manner as described above. However, the conversion formula is prepared corresponding to the speed at the time of collision of the hammer.

Embodiment 3 Embodiment 3 is an automatic penetration tester in which the weight of a hammer is changed. As described above, the guide rod 10 is placed at three predetermined height positions via the sensor bracket 27 in the first position from the lowest position,
The solenoid 16 is fixedly provided near the second and third height sensors 22, 23, 24 and the third height sensor 24. The solenoid 16 is provided with a movable iron core 17 slidable in the horizontal direction by a change in the magnetic field. In addition to the hammer 9 that moves up and down, weights 15 and 19 are fitted to the guide rod 10. The weights 15 and 19 are provided with an iron core receiver 18 and a sensor dog 21 which engage with the movable iron core 17, respectively. Normally, the movable iron core 17 is engaged with the iron core receiver 18 of the weight 15, and the weights 15, 19 are stopped at predetermined positions. The movable iron core 17 is provided so as to be able to engage with the iron core receiver 18 when the weight reaches a position detected by the third height sensor.

As described above, when the penetrating impossible state is detected, first, the hammer 9 is raised to the height detected by the second height sensor 23. Next, the solenoid 16 is driven and the movable iron core 17 is slid in the direction of the solenoid 16 in the figure to release the engagement with the weight 15. Then, the hammer 9 is slowly lowered. At this time, the weights 15 and 19 descend together with the hammer 9. When the third height detection sensor 24 detects the sensor dog 21 of the weight 19, the lowering of the hammer 9 is stopped. Then, the solenoid 16 is driven again to slide the movable iron core 17, and the iron core receiver 1 of the weight 19 is moved.
8 is engaged. In addition, hammer 9 and weight 15 are first
By lowering the hammer of the automatic penetration tester to the height detected by the height sensor 22 of
The weight of 5 can be regarded as the added weight. Also,
When it is necessary to add a weight, the above-described operation is repeated to add the weight 19, and when the weight is removed, the reverse operation may be performed. In the embodiment, the weight can be automatically removed. However, the weight may be manually removed. The bearing capacity can be determined in the same manner as described above. However, the conversion formula is prepared according to the weight of the hammer.

[0024]

According to the construction of the automatic penetration tester according to the first aspect of the present invention, even if the stratum is a hard stratum or a soft stratum having many rocks or pebbles, for example, the striking force of the driving device is changed to accurately determine the ground strength and penetration. Measurements such as quantities can be made. In addition, it is possible to save time and labor for re-measurement due to inability to penetrate, and it is possible to suppress the cost required for measuring the ground strength and the like. Further, it is possible to detect a very dangerous stratum for a house or the like in which a soft stratum is present under a very hard stratum.

According to the configuration of the automatic penetration tester according to the second aspect, the impact force can be changed by changing the hammer falling distance, so that the ground strength, the penetration amount, etc. can be accurately measured. Can be. In addition, it is possible to save time and labor for re-measurement due to inability to penetrate, and it is possible to suppress the cost required for measuring the ground strength and the like. Further, it is possible to detect a very dangerous stratum for a house or the like in which a soft stratum is present under a very hard stratum.

According to the configuration of the automatic penetration tester according to the third aspect, the impact force can be changed by changing the speed at the time of collision of the hammer with the penetration portion, so that the ground strength and the penetration amount can be accurately determined. Etc. can be measured. In addition, it is possible to save time and labor for re-measurement due to inability to penetrate, and it is possible to suppress the cost required for measuring the ground strength and the like. Further, it is possible to detect a very dangerous stratum for a house or the like in which a soft stratum is present under a very hard stratum.

According to the configuration of the automatic penetration tester according to the fourth aspect, the impact force can be changed by changing the weight of the hammer, so that it is possible to accurately measure the ground strength, the penetration amount, and the like. it can. In addition, it is possible to save time and labor for re-measurement due to inability to penetrate, and it is possible to suppress the cost required for measuring the ground strength and the like. Further, it is possible to detect a very dangerous stratum for a house or the like in which a soft stratum is present under a very hard stratum.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an automatic penetration tester according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an automatic penetration tester according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating an automatic penetration tester according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 support 2 base 3 adjuster 4 chain 5 sprocket 6 motor 7 clutch 8 connecting member 9 hammer (drive-in device) 10 guide rod 11 knocking head 12 rod (penetration part) 13 wheel 14 encoder 15 weight 16 solenoid 17 movable iron core 18 iron core holder 19 Weight 201 Upper guide arm 202 Lower guide arm 21 Sensor dog 22 First height sensor 23 Second height sensor 24 Third height sensor 25 Brake 26 Guide roller 27 Sensor bracket

Claims (4)

[Claims] 1. An automatic penetration tester comprising a penetrating portion and a driving device for penetrating the penetration portion into the ground by hitting, wherein a striking force variable device for changing the striking force of the driving device to a predetermined force is provided. Automatic penetration testing machine characterized by the following. 2. The driving device according to claim 1, wherein the driving device includes a hammer that falls at an equal acceleration, and the hitting force changing device is a device that changes the hitting force by changing a falling distance of the hammer. The automatic penetration tester according to claim 1. 3. The hitting device comprises a hammer, and the hitting force changing device is a device for changing the hitting force by changing a speed of the hammer at the time of collision with the penetrating portion. The automatic penetration tester according to claim 1. 4. The automatic penetration tester according to claim 1, wherein said driving device is constituted by a hammer, and said impact force varying device is a device for changing said impact force by changing a weight of said hammer.