JPH04323536A - Intrusion testing device - Google Patents

Abstract

PURPOSE:To perform an expected dynamic intrusion test simply and efficiently in use of an oil hydraulic hammer and to comprehend and analyze correctly the intrusion test result. CONSTITUTION:A climbing base 3 so supported on a vertical leader 1 as being able to rise and fall, and a climbing base pulling up means 8 being able to switch the climbing base 3 into free fall condition are provided. The climbing base 3 are provided with a vertical shaft for hitting 4 to be connected with a rod for intrusion test 6 and an oil hydraulic hammer 5 to hit the vertical shaft for hitting 4 in the shaft direction. A fall amount detection means 12 detecting the fall amount of the climbing base 3 in regard to the leader 1 is provided and an operation record means 17 operating and recording the change of soil hardness in the intrusion direction of the rod for intrusion test 6 based on the fall amount detected by the fall amount detection means 12 is provided also.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a penetration testing device for conducting a dynamic penetration test to investigate changes in hardness (strength) in the depth direction of the ground.

0002

[Prior Art] As specified by the JIS standard, the standard ground penetration test method involves hammering a rod with a penetrating tip, such as a cone, into the ground using a hammer with a weight of 63.5 kg and a falling height of 75 cm. The number of blows (N) required to penetrate 30 cm perpendicularly to the
This method measures the N value and estimates the hardness (strength) of the ground from this N value, but the conventional equipment for carrying out this penetration test method is a hammer that weighs 63.5 kg. In addition, a guide rod equipped with a knocking head is vertically supported by a trident or the like, a penetration test rod is connected to the lower end of the guide rod, and the hammer is pulled up to a height of 75 cm from the knocking head by a tow rope. The knocking head was struck by falling freely, and the penetration test rod was made to penetrate vertically by this striking force.

[0003] There is also known a structure in which the pulling rope for pulling up the hammer is automatically reeled in to a required amount by power and then released to allow the hammer to fall freely, but in any case, the conventional penetration test The device uses a hammer of a certain weight and repeatedly causes the hammer to fall freely at a certain fall height, and visually measures the amount of penetration of the penetration test rod by the impact of the hammer. The penetration test was performed by measuring the number of strikes with the hammer until the rod penetration amount reached a certain amount.

0004

[Problems to be Solved by the Invention] With the conventional penetration testing device as described above, it takes time and effort to install the device, and the efficiency is low because the hammer is dropped repeatedly, and furthermore, it is difficult to automatically record the test results. There were some problems, such as not being able to do it.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the present invention provides a lifting platform that is supported by a vertical leader so as to be able to rise and fall, and a platform that is capable of freely falling. The lifting platform is provided with a vertical striking shaft to which a penetration test rod is connected, and a hydraulic hammer for striking the vertical striking shaft in the axial direction. a descending amount detecting means for detecting the descending amount of the lifting platform relative to the descending height; and a calculation recording means for calculating and recording a change in ground hardness in the penetration direction of the penetration test rod based on the descending amount detected by the descending amount detecting means. This paper proposes a penetration testing device that is equipped with a

[0006]

Effect of the Invention: While the lifting platform of the penetration test device installed at a predetermined position is raised to a predetermined height by the lifting means, a penetration tip such as a cone is attached to the tip of the striking vertical shaft. By connecting the test rod and operating the hydraulic hammer with the lifting means switched to a state where the lifting platform can freely fall, the total weight of the lifting platform including the hydraulic hammer and the vibration repetition caused by the hydraulic hammer are reduced. By applying a striking force to the penetration test rod, the rod can penetrate into the ground.

[0007]The penetration amount of the rod for the penetration test is
Since the amount of descent of the lifting platform relative to the reader is automatically detected by the amount of descent detection means, the amount of descent (penetration amount) detected by the amount of descent detection means is set to the set value by the calculation recording means. By measuring the time required to reach , it is possible to automatically calculate and record the change in ground hardness in the direction of rod penetration, which is expressed by the time required per unit amount of penetration.

Of course, if a sensor for detecting the number of strikes of the hydraulic hammer is also used, for example, the number of strikes required for the descending amount (penetration amount) detected by the descending amount detecting means to reach a set value can be measured. It is also possible to automatically calculate and record the change in ground hardness in the direction of rod penetration, which is expressed by the number of strikes per unit amount of penetration.

Furthermore, by using a means for detecting the hydraulic pressure supplied to the hydraulic hammer, the number of strikes per unit amount of penetration obtained as described above is determined by the hydraulic pressure detected by the hydraulic pressure detecting means and the rod for the penetration test. Corrected based on the acting vertical load (total load of the lifting platform including hydraulic hammer etc.), so that
It is also possible to obtain an N value that is substantially the same as the test result obtained by the conventional Tekken-type standard dynamic penetration test using a hammer of a constant weight, using the arithmetic and recording means.

0010

[Embodiment] Hereinafter, an embodiment of the present invention will be explained based on the attached illustrative drawings. In FIG. It is supported so that it can be raised and lowered. Reference numeral 4 denotes a vertical striking shaft supported vertically on the lifting table 3, and is struck in the axial direction by a hydraulic hammer 5 mounted on the lifting table 3. Reference numeral 6 denotes a penetration test rod that is detachably connected to the percussion vertical shaft 4, and a penetration tip 7 such as a cone or sampler is attached to the lower end. The rod 6 is constructed by sequentially connecting rods of unit length according to the penetration depth. Reference numeral 8 denotes a means for lifting the lifting platform 3, which consists of a lifting wire 9 whose one end is locked to the lifting platform 3, and a winch 11 that winds the wire 9 through a pulley 10 pivotally supported on the upper end of the leader 1. Therefore, the winding drum of the winch 11 can be made free, and the lifting platform 3 can be switched to a state in which it can freely fall.

Reference numeral 12 denotes a descending amount detecting means for detecting the descending amount of the lifting platform 3 with respect to the reader 1. The descending amount detecting means 12 may be a magnetic linear scale consisting of a scale body 13a attached to the reader 1 and a detector 13b attached to the elevator platform 3, or the like. Any type of system may be used, such as a type that directly reads the value, or a type that counts pulses sent from a pulse encoder that rotates in conjunction with the lifting and lowering of the lifting platform 3 and replaces it with the amount of descent.

Reference numeral 14 denotes a sensor for detecting the number of strikes, which is composed of a vibration sensor etc. attached to the hydraulic hammer 5, and indirectly detects the number of strikes of the hydraulic hammer 5 from the oil pressure supplied to the hydraulic hammer 5. It may be something that is detected. Further, 15 is a hydraulic unit that supplies hydraulic pressure to the hydraulic hammer 5, which includes a hydraulic pressure detection means 16.
is installed.

Reference numeral 17 denotes an arithmetic recording means, which is composed of an arithmetic recording device 18 installed at the test site, for example, on the pedestal 2, and a personal computer 19 installed off-line at a suitable location such as an office. The calculation and recording device 17 includes a CPU 20 that takes in the detection signals from the lowering amount detection means 12, the number of hits detection sensor 14, and the oil pressure detection means 16 and performs calculations according to a program, a display unit 21 that displays the calculation results, and a display unit 21 that displays the calculation results. The personal computer 19 comprises a recording means 23 for recording the recorded contents of the IC card 22, a card reader 24 for reading the recorded contents of the IC card 22, a CPU 25 for processing the read contents according to a program, and displaying the calculation results. It consists of a display means 26 for displaying information, and a printer 27 for printing out the displayed contents.

In the penetration testing apparatus constructed as described above, the penetration testing rod 6 is connected to the striking vertical shaft 4 on the lifting table 3, and the lifting table 3 is set in a state where it can freely fall. By operating the hydraulic hammer 5 by the unit 15, the entire weight of the lifting platform 3 including the hydraulic hammer 5 is applied to the rod 6, and the rod 6 is vibrated in the axial direction, thereby utilizing the penetrating tip 7. The rod 6
can penetrate into the ground. When the rod 6 has penetrated to a predetermined depth, the striking vertical shaft 4 and the rod 6 are separated, and the elevating table 3 is pulled up by the leader 1 by means 8.
The rod 6 is pulled up to the upper end, the upper end of the separated rod 6 and the striking vertical shaft 4 are connected by another unit length rod, the rod 6 is extended, and the rod 6 is struck again with the hydraulic hammer 5. Penetrate.

As described above, the penetration test rod 6 is penetrated by impact, and the amount of penetration at this time, that is, the amount of descent of the lifting platform 3 with respect to the leader 1, is detected based on the detection signal of the amount of descent detection means 12. The number of times the rod is struck by the hydraulic hammer 4 is detected based on the detection signal of the number of strikes detection sensor 14, and the oil pressure supplied to the hydraulic hammer 4 is detected based on the detection signal of the oil pressure detection means 16. These detection data are sent to the CPU of the calculation and recording device 18.
In step 20, calculations are performed according to the program, and the required penetration time T for each unit penetration amount D (for example, 5 cm or 10 cm), the required number of penetration blows N for each unit penetration amount D, and the required penetration number N for each unit penetration amount D. It is processed into a recording format such as the required penetration impact force P and is automatically recorded on the IC card 22,
If necessary, each of the recording formats can be displayed in a graph form by the display means 21.

The data recorded on the IC card 22 can be transferred to the personal computer 19 using the IC card 22.
The card can be set in the card reader 24, read by the CPU 25, output to the printer 27, and printed out on chart paper. For example, the required penetration time T for each unit penetration amount D is determined by the vertical axis being the penetration depth, as shown in FIG.
It can be printed out as a T/D curve representing the required penetration time T for each unit penetration amount D, with the horizontal axis as the required penetration time, and the number of blows N required for each unit penetration amount D is:
As shown in FIG. 3, the vertical axis is the penetration depth and the horizontal axis is the number of blows, and N/D represents the number of blows N required for penetration per unit penetration amount D.
It can be printed out as a curve. Further, a P/D curve representing the required penetration force P for each unit penetration amount D can also be printed out in the same manner. Of course, these T/D curves, N/D curves, or P/D curves can also be displayed by the display means 26 if necessary.

Furthermore, taking into consideration data such as the hydraulic pressure value detected by the hydraulic pressure detection means 16 and the static load value acting on the rod 6 (total weight value of the lifting platform 3 including the hydraulic hammer 4),
The required number of penetration strikes N for each unit penetration amount D is the test result in a standard penetration test in which a hammer of a constant weight is dropped freely from a constant height and the rod is penetrated by striking, that is, the number of strikes required for penetration of 30 cm. It is also possible to incorporate a program that automatically corrects the data to be substantially the same as the number of hits N, and print out this corrected data on the printer 27 or display it on the display means 26.

Next, an example of the specific structure of the above-mentioned penetration test device is shown in FIG.
~ To explain based on FIG. 7, in FIG.
is installed. This leader 31 has a horizontal support shaft 32
A leader support stand 34 is pivotally supported around the cylinder unit 33 so as to be able to swing back and forth, and is supported at a predetermined angle by the cylinder unit 33.
It is held movably up and down, and its height is adjusted by a cylinder unit 35. Reference numeral 36 denotes a lifting platform, which lifts the leader 3 through rollers 38 (see FIG. 6) that engage with guide rails 37 laid on both left and right sides of the leader 31.
It is supported so as to be movable up and down along the vertical axis 3 for striking.
9, a hydraulic hammer 40 that applies an axial impact force to the perpendicular percussion shaft 39, and hydraulic motors 41 and 42 that apply rotational force in any forward or reverse direction to the perpendicular percussion shaft 39. .

As shown in FIG. 5, the striking vertical shaft 39 is spline-fitted to a driven gear 43 supported on the lifting table 36 so as to be slidable within a certain range in the axial direction. Two drive gears 44, 45 that mesh with the hydraulic motors 41, 42 are attached to the drive shafts of the hydraulic motors 41, 42. By distributing and supplying a constant hydraulic pressure to both the hydraulic motors 41 and 42, the percussion vertical shaft 39 is driven at low speed in forward and reverse arbitrary directions via both drive gears 44 and 45 and driven gear 43. You can also use the hydraulic motor 4 on one side.
By supplying a constant hydraulic pressure only to the drive gear 1, the perpendicular impact shaft 39 can be driven in any forward or reverse direction at high speed via the driving gear 44 and the driven gear 43 on one side. Of course, while the hydraulic hammer 40 is striking the striking vertical shaft 39 in the axial direction, the hydraulic motors 41 and 42 are
This enables the perpendicular hitting shaft 39 to be rotationally driven.

The lifting means for raising the lifting platform 36 along the leader 31 is constructed as follows. That is, as shown in FIGS. 6 and 7, an elevating drive shaft 48 that is rotatably driven in any forward or reverse direction by a motor 47 equipped with a brake 46 is horizontally supported on the elevating table 36. A clutch 50 is interposed between the drive shaft 48 and the lifting drive gear 49 which is loosely supported in a relatively rotatable manner. The clutch 50 includes a movable clutch piece 51 spline-fitted to the drive shaft 48, and a passive pawl 51b connected to the drive gear 49 so as to be able to engage and disengage from the transmission pawl 51a of the movable clutch piece 51. , a shift lever 52 for operating the movable clutch piece 51, and an actuator 53 for driving the shift lever 52, but any other type of clutch may be used.

As shown in FIG. 6, the leader 31 is provided with a chain 54 that engages with the lifting drive gear 49 of the lifting platform 36, with only both ends of the chain 54 fixed to both ends of the leader 31. The chain 5 is mounted on the lifting platform 36.
Guide free tooth wheels 55 and 56 for engaging the drive tooth wheel 49 with the drive tooth wheel 49 are pivotally supported.

As shown in FIG. 4, a rod clamp 57 and a wrench 58 for rod rotation operation are provided at the lower end of the leader 31, which are used for cutting off each unit rod constituting the penetration test rod 6. installed.

In the penetration testing apparatus constructed as described above, the lowering amount detection means 12, the number-of-strikes detection sensor 14, the hydraulic unit 15, and the hydraulic pressure detection means 16 shown in FIG.
, calculation recording means 17, etc. are not shown in the figure, but the penetration test rod 6 is set on the perpendicular impact shaft 39, and the penetration test rod 6 is shafted through the perpendicular percussion shaft 39 with the hydraulic hammer 40. By striking in the direction, a penetration test can be performed as described above. At this time, by disengaging the clutch 50 of the lifting platform pull-up means shown in FIG. As the rod 6 penetrates by impact, it can freely fall along the leader 31.

[0024] Also, during the penetration test, the hydraulic motor 41,
42 forcibly rotates the rod 6 via the striking vertical shaft 39 to enhance the effect of crushing gravel etc. by the penetrating tip 7,
It is possible to achieve rapid penetration through particularly hard strata. Of course, the forced rotational drive of the perpendicular percussion shaft 39 by the hydraulic motors 41 and 42 can also be used when the perpendicular percussion shaft 39 and the rod 6 are screwed together or when the screwed connection is released.

[0025] When adding and extending the rod 6,
During the extraction work, it is necessary to forcibly move the lifting platform 36 upward. At this time, the shift lever 52 of the clutch 50 shown in FIG. The motor 47 is operated in a predetermined direction with the elevating drive shaft 48 and the elevating drive gear wheel 49 connected by engaging them. Of course, at this time, the brake 46 is automatically released. Therefore, the rotation of the lifting drive shaft 48 is controlled by the clutch 5.
The rotation of the lifting driving gear 49 that engages with the fixed chain 54 applies a thrust in the upward direction to the lifting platform 36, and the lifting platform 3
6 moves upward along the leader 31.

When the lifting platform 36 that has risen to a predetermined height is to be stopped and fixed to the leader 31, the motor 47 is stopped without disengaging the clutch 50, and the brake 4 is stopped.
6 and lock the elevating drive shaft 48. When the motor 47 rotates the elevating drive shaft 48 in the opposite direction, the elevating table 36 is forcibly moved downward, thereby forcibly pushing down the penetration test rod 6.

[0027]

As described above, according to the penetration testing device of the present invention, by simply operating the hydraulic hammer with the leader set in a predetermined position, the total weight of the lifting platform side including the hydraulic hammer and the hydraulic hammer can be reduced. By applying a vibratory repeated impact force to the penetration test rod, the rod can be efficiently penetrated into the ground, and the desired dynamic penetration test can be easily and efficiently performed.

Moreover, changes in the ground hardness in the direction of rod penetration, expressed by the time required per unit amount of penetration, and changes in ground hardness in the direction of rod penetration, expressed by the number of hits per unit amount of penetration, are automatically measured. In addition, if necessary, the N value can be automatically calculated, which is virtually the same as the test result obtained by the conventional Tekken-type standard dynamic penetration test using a hammer with a constant weight. Since it can also be recorded, it becomes possible to accurately understand and analyze the penetration test results.

[Brief explanation of drawings]

FIG. 1 is a schematic side view and block diagram illustrating the overall configuration of the device of the present invention.

FIG. 2 is a diagram showing a chart paper on which a T/D curve, which is the result of a penetration test, is printed.

FIG. 3 is a diagram showing a chart paper on which an N/D curve, which is the result of a penetration test, is printed.

FIG. 4 is a side view showing the specific structure of the penetration test device.

FIG. 5 is a front view showing a drive means for the perpendicular shaft for impact of the device.

FIG. 6 is a side view showing the elevating platform lifting means of the device.

FIG. 7 is a front view showing a main part of the elevating platform lifting means of the device.

[Explanation of symbols]

1, 31...Leader, 3, 36... Lifting platform, 4, 39...vertical shaft for hitting; 5,40...Hydraulic hammer, 6...Penetration test rod, 7...Penetration tip, 8... Lifting platform lifting means, 9...Wire for lifting the lifting platform, 11...Winch, 12...Elevating platform lowering amount detection means, 14...Sensor for detecting the number of hits, 15...hydraulic unit, 16...Oil pressure detection means, 17...Calculation recording means, 18... Arithmetic recording device, 19...Personal computer, 41, 42...hydraulic motor, 46...brake, 47...Motor, 48...Elevating drive shaft, 49...Elevating drive gear wheel, 50...clutch, 53...Clutch switching actuator, 54...Chain.

Claims (4)

[Claims] Claim 1: A lifting platform supported by a vertical leader so as to be able to rise and fall; and lifting platform lifting means capable of switching the lifting platform to a free-falling state; and a hydraulic hammer for striking the vertical striking shaft in the axial direction,
A descending amount detecting means for detecting the descending amount of the lifting platform with respect to the leader, and a calculation record for calculating and recording a change in ground hardness in the penetration direction of the penetration test rod based on the descending amount detected by the descending amount detecting means. A penetration testing device that is equipped with a means. 2. A sensor for detecting the number of strikes of the hydraulic hammer, wherein the calculation recording means detects the number of strikes of the penetration test rod based on the descending amount detected by the descending amount detecting means and the number of strikes detected by the sensor. The penetration testing device according to claim 1, which calculates and records changes in ground hardness in the direction of penetration. 3. A device for detecting oil pressure supplied to the hydraulic hammer, wherein the calculation recording device detects the amount of descent detected by the amount detection device and the number of strikes detected by the sensor.
and based on the oil pressure etc. detected by the oil pressure detection means, a unit penetration depth that is substantially the same as the test result in a standard penetration test in which a hammer of a certain weight is freely dropped from a certain height and the rod is penetrated by impact. 3. The penetration testing device according to claim 2, which calculates and records changes in ground hardness expressed by the number of times each impact is made. 4. The penetration testing apparatus according to claim 1, wherein the elevating table is equipped with a hydraulic motor for driving the striking vertical shaft in forward and reverse rotation.