JP2004092201A - Automatic penetration tester - Google Patents

Abstract

[PROBLEMS] To provide an automatic penetration tester that eliminates inertia at the time of penetration of a penetration rod 7 and enables highly accurate soil layer determination.
The present invention controls the powder brake (11) and the chuck motor (5) in the load-loading unit when the penetrating rod (7) penetrates into the ground to increase or decrease the load applied to the penetrating rod (7). The rotation of the penetrating rod 7 is given and stopped. On the other hand, when the load applied to the penetrating rod 7 is reduced and when the rotation of the penetrating rod 7 is stopped, the electromagnetic brake 8b provided on the elevating motor 8 is operated to reduce the penetration of the penetrating rod 7. Stop once. As a result, the inertia of the penetrating rod 7 can be removed and the penetrating rod 7 can be prevented from penetrating unnecessarily.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic penetration tester that performs a test for investigating the hardness of ground.
[0002]
[Prior art]
As a conventional automatic penetration tester for performing the Swedish sounding test method or a test method based thereon, those disclosed in JP-A-8-292141 and JP-A-9-111745 are known. In such a conventionally known automatic penetration tester, when the penetration rod is rotated to penetrate into the ground, the penetration rod is rotated at a predetermined rotation speed. When the penetration speed of the penetration rod during rotation penetration is equal to or higher than a predetermined limit rotation penetration speed, a phenomenon occurs in which the penetration rod penetrates into the ground only by load without applying rotation, that is, without applying rotation. Is determined, the rotation is stopped, and the load applied to the penetrating rod is changed as necessary. The maximum speed value at which a screw point that has been given a single twist at 200 mm according to the provisions of Japanese Industrial Standard A1221 penetrates into the ground according to the torsion is set as the limit rotational penetration speed. The value determined by is given.
Critical rotation penetration speed (unit: mm / s) = maximum amount that screw point can penetrate per rotation according to torsion (200 mm) × rotation speed of penetration rod (unit: rpm) ÷ 60 (unit: sec)
[0003]
[Problems to be solved by the invention]
If self-sinking occurs while rotating the penetrating rod and penetrating into the ground, the rotation of the penetrating rod is stopped and switched to penetrating only by load, but the penetrating rod has an inertial force based on the previous penetration. If there is a hard layer that does not cause self-settling immediately below the soil layer determined to have self-settling, the penetrating rod penetrates into the hard layer due to inertia, and the hard layer and the soil layer that was settled automatically Can not be determined accurately. In addition, when the hard layer has a thin structure, the penetration rod penetrates through the hard layer, and the hard layer itself cannot be distinguished. Also, if the penetrating rod reaches the softer soil layer while it is sinking, the load is reduced there, but at this time the penetrating rod further penetrates due to the inertia up to that point, and the boundary of the soil layer There have been problems such as inability to detect accurately.
[0004]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and has a penetrating rod configured to be able to penetrate into the ground, restraining means capable of restricting the penetration of the penetrating rod into the ground, and a grounding rod. And a control unit for controlling the stopping means as necessary to temporarily stop the penetration of the penetrating rod.
[0005]
Further, the present invention provides a penetrating rod configured to be able to penetrate into the ground, a rotation driving unit for rotationally driving the penetrating rod, a load load unit for applying a predetermined load to the penetrating rod, Restraining means provided to restrain the penetration rod from penetrating into the ground; and, when the penetration rod is penetrating into the ground, controlling the load loading unit to increase or decrease the load applied to the penetration rod. At the same time, while controlling the rotation driving means to switch between applying and stopping rotation to the penetrating rod, controlling the stopping means at each of reducing the load applied to the penetrating rod and stopping the rotation of the penetrating rod. And a control unit for temporarily stopping the penetration of the penetration rod.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 5, reference numeral 1 denotes an automatic penetration tester, which includes an elevator 3 configured to be able to move up and down along a column 2. The lifting table 3 includes weights 4 a and 4 b having a predetermined weight, a chuck motor 5 which is an example of a rotation driving unit, a chuck unit 6 which can be rotated by being driven by the chuck motor 5, 6, a penetrating rod 7 configured to be integrally rotatable, an elevating motor 8 for elevating the elevating platform 3, and a chain member 2a arranged in the longitudinal direction of the back surface of the support column 2. A sprocket 9 that can rotate by rotation, a support shaft 10 that rotates integrally with the sprocket 9, and a powder brake 11 that is connected to the support shaft 10 are arranged. The penetrating rod 7 can be loaded with a load of 1 KN by the total weight of the elevator 3 and the equipment arranged on the elevator 3. In the present embodiment, an example of the load applying unit described in the claims is constituted by the elevating platform 3 and each of the equipments arranged thereon. The configuration of each of these devices is the same as that disclosed in JP-A-8-292141.
[0007]
The penetrating rod 7 includes a rod portion 7a held by the chuck unit 6 and a screw point 7b connected to a tip of the rod portion 7a. The screw point 7b is configured in accordance with Japanese Industrial Standard A1221, and has a sharp drill shape with one twist applied to a length of 200 mm.
[0008]
The chuck motor 5 and the chuck unit 6 are connected by winding an endless chain 26 around a sprocket 24 connected to an output shaft 5a of the chuck motor 5 and a sprocket 25 integrally connected to a lower portion of the chuck unit 6. Have been. The output shaft 5a of the chuck motor 5 and the sprocket 24 are connected via a one-way clutch 27. The one-way clutch 27 is adapted to screw the screw point 7b into the ground in accordance with the twist. When the chuck motor 5 is driven to rotate (hereinafter, for convenience, the drive of the chuck motor 5 is referred to as normal rotation drive), the drive is transmitted to the sprocket 24. Therefore, the penetration rod 7 rotates in response to the forward rotation of the chuck motor 5. Conversely, when a rotation in a direction of screwing the screw point 7b into the ground and screwing it into the ground is input from the sprocket 24 side, the one-way clutch 27 idles with respect to the output shaft 5a. Therefore, when the screw point 7b receives the resistance of the soil and rotates according to the twist, the one-way clutch 27 idles with respect to the output shaft 5a, and the penetrating rod 7 is connected to the resistance of the speed reduction mechanism built in the chuck motor 5. It can rotate without receiving it. That is, the penetrating rod 7 is rotatable by the resistance of the soil in the penetrating state where the chuck motor 5 is not driven.
[0009]
The elevating motor 8 and the support shaft 10 are connected by meshing of bevel gears 12 and 13. A one-way clutch 14 is interposed between the bevel gear 13 and the support shaft 10, and the operation of the one-way clutch 14 drives the elevating motor 8 to rotate the sprocket 9 in the direction in which the elevating platform 3 moves up. The driving of the lifting motor 8 is transmitted to the sprocket 9 through the bevel gears 12 and 13 and the support shaft 10 only when the driving is performed for the sake of convenience. Conversely, when the lifting motor 8 is driven (for the sake of convenience, this driving is referred to as reverse rotation driving), the bevel gear 13 idles with respect to the support shaft 10 by the action of the one-way clutch 14. For this reason, it is possible to create a state in which the deceleration resistance of the speed reduction mechanism of the elevating motor 8 is not transmitted to the support shaft 10, and thus it is possible to purely apply the load based on the weight of the elevating platform 3 or the like to the penetrating rod 7. . Further, as shown in Japanese Patent Application Laid-Open No. 8-334143, the elevating motor 8 has a built-in electromagnetic brake 8b that operates to lock the output shaft 8a so that it cannot rotate when the power is cut off. . The electromagnetic brake 8b operates in conjunction with power supply to the lifting motor 8.
[0010]
The powder brake 11 includes a support shaft 10 and is configured to brake the support shaft 10 when necessary. The braking force is determined by a load current supplied from a brake control unit 20 of a control unit 15 described later. It is changed gradually. As described above, the powder motor 11 brakes the support shaft 10 in a state where the lifting motor 8 is driven in the reverse direction and the load based on the weight of the lifting platform 3 and its equipment is applied to the penetration rod 7, so that the penetration rod 7 is changed. That is, the load applied to the penetrating rod 7 is
The load (1 KN) based on the weight of the lifting platform is equal to the braking force of the powder brake 11.
[0011]
The control unit 15 for controlling the operation of the automatic penetration tester 1 includes a speed indexing unit 17 connected to an arithmetic processing unit 16, a lifting motor driving unit 18, a chuck motor driving unit 19, a brake control unit 20 , A storage unit 21, and an input unit 22. The speed indexing unit 17 obtains a pulse generated per unit time from a pulse signal obtained by ON / OFF of a sensor 23 that detects a tooth of the rotating sprocket 9, and calculates a penetration speed of the penetration rod 7 from this. It is configured. Further, the storage unit 21 stores a load current value to be applied to the powder brake 11, a limit rotation penetration speed calculated by the formula shown in the section of the related art according to the rotation speed given to the penetration rod 7, and other control parameters. Is stored.
[0012]
The penetration test by the automatic penetration tester 1 is performed in accordance with the Swedish sounding test method of Japanese Industrial Standard A1221. First, penetration by only a load that does not apply rotation to the penetration rod 7 (hereinafter, referred to as self-sinking penetration) is performed. At this time, the load applied to the penetration rod 7 is increased or decreased stepwise according to the penetration speed calculated by the speed indexing unit 17. That is, the arithmetic processing unit 16 sends a command signal to the brake control unit 20 according to the penetration speed calculated by the speed indexing unit 17, and the brake control unit 20 is applied to the powder brake 11 according to the command signal. Change the current. Thereby, the load applied to the penetrating rod 7 is increased or decreased in six stages of 50N, 150N, 250N, 500N, 750N, and 1KN. The load applied to the penetrating rod 7 is increased by one step each time the penetrating rod 7 reaches a harder soil layer and does not self-sink. Conversely, when the penetration rod 7 reaches the softer soil layer and the penetration speed exceeds a predetermined reference value, it is reduced by one step each time. During the penetration test, the elevating motor drive unit 18 controls the current applied to the elevating motor 8 and constantly drives the elevating motor 8 in reverse. As a result, the one-way clutch 14 idles, and the load based on the weight of the lift 3 and the like is accurately applied to the penetrating rod 7 without being affected by the reduction ratio of the lift motor 8.
[0013]
When the load is reduced when the penetrating rod 7 penetrates by itself, the arithmetic processing unit 16 issues a command signal for instructing the brake control unit 20 to change the applied current, and also sends a command signal to the lifting motor drive unit 18 to the lifting motor 8. A command signal is sent to temporarily interrupt the current (power supply) applied to the. In response to this, the electric current supplied to the elevating motor 8 is cut off by the elevating motor driving unit 18, the reverse rotation drive of the elevating motor 8 is temporarily stopped, and the brake mechanism 8 b is operated to output the output shaft of the elevating motor 8. 8a is locked so that it cannot rotate. For this reason, the lift 3 is once forcibly stopped, and the inertial force inherent in the penetrating rod 7 in the previous penetrating state is removed. As described above, when the load is changed, the penetration of the penetrating rod 7 is forcibly stopped once to remove the inertial force, thereby preventing the extra penetration rod 7 from penetrating due to inertia.
[0014]
Thereafter, a reverse drive command signal is again supplied to the lifting motor drive unit 18, whereby a reverse drive current is applied from the lift motor drive unit 18 to the lifting motor 8, the electromagnetic brake 8 b is released, and the output is output. The shaft 8a resumes reversing. Therefore, the penetrating rod 7 can penetrate into the ground under the load reduced by one step.
[0015]
At the time of self-settling, the soil resistance of the soil layer (self-settling layer) acts on the screw point 7b. The resistance of the soil acts as a force for turning the screw point 7b because the screw point 7b has a twisted shape. Here, if the screw point 7b is constrained, for example, the deceleration resistance of the chuck motor 5 acts on the penetrating rod 7, the screw point 7b cannot rotate according to the soil resistance. It becomes a brake resistance, and the penetrating rod 7 cannot penetrate the soil layer that should originally penetrate by self-settling. This becomes more remarkable in an auto-settling soil layer in which the soil layer is relatively tight and the soil resistance is high. In other words, if the screw point 7b cannot rotate due to the resistance of the soil, the soil layer where the soil is relatively tight but low-speed self-settling cannot occur cannot be determined.
[0016]
However, in the present automatic penetration tester 1, when the screw point 7b tries to rotate due to the resistance of the soil while the driving of the chuck motor 6 is stopped, the one-way clutch 27 idles with respect to the output shaft 5a. I do. Therefore, the penetrating rod 7 including the screw point 7b can rotate without opposing the resistance of the soil which the screw point 7b receives. Therefore, even for a relatively tight soil layer in which self-settling in a low-speed region occurs, the penetration rod 7 can be self-settled and penetrated under an accurate load state, and the soil layer can be accurately determined.
[0017]
As described above, the penetrating rod 7 self-submerges into the ground by changing the load. When the penetrating rod 7 does not self-penetrate with only a load of 1 KN, the arithmetic processing unit 16 then sends the same to the chuck motor driving unit 19. A command signal is sent, and the chuck motor 5 is driven to rotate forward. In response to this, the penetration rod 7 rotates, and the rotation penetration is performed with a load of 1 KN applied.
[0018]
During the rotational penetration, the penetration speed of the penetration rod 7 is continuously calculated by the speed indexing unit 17 and sent to the arithmetic processing unit 16. In the arithmetic processing unit 16, this penetration speed is compared with the limit rotation penetration speed read from the storage unit 21.
[0019]
When the screw point 7b reaches a relatively soft soil layer where self-sinking occurs, the penetration speed of the penetrating rod 7 increases. When the penetration speed exceeds the limit rotation penetration speed, the arithmetic processing unit 16 determines that self-sinking has occurred. Then, a drive stop command signal is given to the chuck motor drive unit 19. In response to this, the chuck motor driving unit 19 stops driving the chuck motor 5.
[0020]
The arithmetic processing unit 16 sends a drive stop command signal to the chuck motor drive unit 19 and, at the same time, sends a command signal to the lift motor drive unit 18 to temporarily cut off the current (power supply) applied to the lift motor 8. In response to this, the electric current supplied to the elevating motor 8 is cut off by the elevating motor driving unit 18, the reverse rotation drive of the elevating motor 8 is temporarily stopped, and the brake mechanism 8 b is operated to output the output shaft of the elevating motor 8. 8a is locked so that it cannot rotate. For this reason, the inertial force inherent in the penetration rod 7 at the time of rotation penetration is removed.
[0021]
Thereafter, a reverse drive command signal is again supplied to the lifting motor drive unit 18, whereby a reverse drive current is applied from the lift motor drive unit 18 to the lifting motor 8, the electromagnetic brake 8 b is released, and the output is output. The shaft 8a resumes reversing. Therefore, the penetrating rod 7 is self-sinking and penetrated under a load of only 1 KN. Thereafter, the load change or the rotation application / stop is repeated according to the penetration speed of the penetration rod 7.
[0022]
As described above, the penetration test is usually performed to a depth of 10 m to 15 m underground while switching between self-sinking and rotating penetration as necessary. In the meantime, the history of the load change in the case of self-sinking penetration, and the half rotation number required for the penetration rod 7 to penetrate 250 mm in the case of rotation penetration (the rotation of the penetration rod 7 counted as one rotation of the penetration rod 7 as 2). ) Are stored in the storage unit 21 in correspondence with the penetration depths. After the end of the test, the ground hardness at the point where the test was performed is determined from the load at each depth, the half-rotation speed at the time of rotation penetration, and the like recorded as test data in the storage unit 21.
[0023]
In the above description, an example in which the electromagnetic brake 8b built in the elevating motor 8 is used as the stopping means has been introduced. For example, the powder brake 11 constituting a part of the load changing unit is used as the stopping means. Alternatively, the electromagnetic brake 8b and the powder brake 11 may be used in combination as a stopping means. Further, when stopping the penetrating rod 7, the braking effect by the back electromotive force of the elevating motor 8 may be used, or a separate brake structure may be arranged in the elevating part 3 to use this as the stopping means. As described above, the restraining means described in the claims can employ conventionally known mechanisms and methods without departing from the gist of the present invention. The effect obtained when adopting is the same.
[0024]
【The invention's effect】
The automatic penetration tester according to the present invention temporarily stops the penetration of the penetration rod as necessary when the penetration rod penetrates into the ground. For this reason, the inertial force of the penetrating rod can be eliminated when self-sinking occurs during the rotational intrusion or when it is necessary to reduce the load during the self-sinking intrusion. Therefore, when there is a hard soil layer immediately below the soil layer where self-settling occurs, it is necessary to reduce the load when the penetrating rod reaches the soil layer where self-setting occurs during rotational penetration, or during self-settling Furthermore, when the soft soil layer is reached, it is possible to prevent the penetration rod from excessively penetrating into the soft soil layer due to inertia. Further, even when there is a hard soil layer immediately below the soil layer where self-settling occurs, it is possible to prevent the penetration rod from penetrating into the hard soil layer by inertia. Furthermore, even in the case where there is a thin and hard soil layer that does not cause self-settling between the soil layers that penetrate into itself, the penetration rod can be prevented from penetrating through such a thin soil layer by inertia. As described above, according to the present invention, there is an advantage that it is possible to accurately and finely determine the boundary of the soil layer, and it is possible to perform a more accurate penetration test.
[Brief description of the drawings]
FIG. 1 is a block diagram of an automatic penetration tester according to the present invention.
FIG. 2 is a perspective view of the automatic penetration tester according to the present invention.
FIG. 3 is an enlarged partial cutaway sectional view of a main part of the automatic penetration tester according to the present invention.
FIG. 4 is an enlarged partial cutaway sectional view of a main part of the automatic penetration tester according to the present invention.
FIG. 5 is an enlarged perspective view of an essential part of the automatic penetration tester according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Automatic penetration test machine 2 Post 3 Lifting stand 4a Weight 4b Weight 5 Motor for chuck 6 Chuck unit 7 Penetration rod 7a Rod part 7b Screw point 8 Lifting motor 9 Sprocket 10 Support shaft 11 Powder brake 12 Bevel gear 13 Bevel gear 14 One-way clutch 15 control unit 16 arithmetic processing unit 17 speed indexing unit 18 elevating motor drive unit 19 chuck motor drive unit 20 brake control unit 21 storage unit 22 input unit 23 sensor 24 endless chain 25 sprocket 26 sprocket 27 one-way clutch

Claims (2)

A penetrating rod configured to penetrate the ground,
Stopping means capable of stopping the penetration of the penetration rod into the ground,
An automatic penetration test machine comprising: a control unit that controls the stopping means as necessary when the penetration rod penetrates into the ground to temporarily suspend penetration of the penetration rod. A penetrating rod configured to penetrate the ground,
Rotation driving means for rotationally driving the penetrating rod,
A load applying unit for applying a predetermined load to the penetrating rod,
Restraining means provided to restrain the penetration of the penetration rod into the ground,
When the penetrating rod is penetrating into the ground, the load applied unit is controlled to increase or decrease the load applied to the penetrating rod, and the rotation driving means is controlled to apply / stop rotation to the penetrating rod. A control unit that controls the stopping means to temporarily stop the penetration of the penetration rod when the load applied to the penetration rod is reduced and when the rotation of the penetration rod is stopped. Features an automatic penetration tester.

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