JP3059700B2 - Ground density measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground density measuring device for measuring the density of a ground.

[0002]

2. Description of the Related Art In embankment work, the density of the compacted ground is measured and the compaction degree is measured in order to satisfy the functional properties required at the time of completion, such as the strength of the ground, deformation due to load, and residual settlement. Construction is being performed while managing the work.

At this time, as a method for measuring the density of the compacted ground, a method based on the simplest principle called a "sand replacement method" has been used in many cases. in this way,
A small hole is dug in the ground, and the density and density of the ground are determined by accurately measuring the volume and weight of the excavated soil. In recent years, a ground density measuring method using an RI moisture density measuring device has also been used.
In this method, the density of the ground is measured using the transmission characteristics of radiation (gamma rays) in the soil.

[0004]

However, the conventional measuring method has the following problems.

[0005] That is, in the above sand displacement method, it takes at least about 24 hours until the density is obtained from the measurement operation. On the other hand, when the method using the RI moisture density measuring device is adopted. However, it takes about 15 minutes to several tens of minutes. Therefore, there is a problem that an enormous amount of time is required when the compaction degree of the embankment is measured over a wide range.

[0006] Such a problem is not limited to the measurement of the degree of compaction of the embankment, but is a problem that can generally occur when the density of the ground is measured.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a ground density measuring device capable of accurately measuring the density of the ground in a short time. .

[0008]

The present invention employs an apparatus for measuring the density of the ground by dropping and penetrating the cone with a weight into the ground and measuring the acceleration at that time. The above object is achieved by devising the configuration.

That is, in the ground density measuring apparatus according to the present invention, as described in claim 1, the cone with the weight is allowed to freely fall from a predetermined height to penetrate the ground, and the weight at the time of the ground penetration is obtained. An apparatus for measuring the density of the ground by measuring the acceleration of the cone with a weight, a clamp device that is detachably connected to the cone with a weight,
A first lifting / lowering drive device for raising / lowering this clamp device, a height setting member extending vertically in the vicinity of the clamp device, a second lifting / lowering drive device for raising / lowering this height setting member, and the first and second driving devices And a supporting member for supporting the lifting drive device.After setting the drop reference position by lowering the height setting member and bringing the lower end portion of the height setting member into contact with the ground surface, Lowering the clamp device to a drop reference position, and then releasing the engagement of the clamp device with the cone with the weight, so that the cone with the weight can be freely dropped, Is what you do.

The above-mentioned "cone with weight" means a downward cone having a weight (weight) integrally provided at the upper end. The shape of the "cone" does not necessarily have to be a conical shape as long as it has a pointed shape that can penetrate the ground when the cone with the weight is freely dropped from the predetermined height. The shape may be a pyramid or the like.

The "disengagement" operation of the clamp device with respect to the cone with the weight may be performed by an operator directly operating the clamp device, or the operator operates a remote switch. May be performed automatically, or may be performed automatically in conjunction with the completion of the lowering operation of the clamp device to the drop reference position.

[0012]

As described above, the ground density measuring apparatus according to the present invention drops the cone with the weight and penetrates the ground, and measures the acceleration at that time. By analyzing the acceleration, the density of the ground can be accurately measured in a short time, but in order to realize this, it is necessary to accurately set the drop height of the cone with the weight.

In this respect, the ground density measuring apparatus according to the present invention sets the drop reference position by lowering the height setting member and bringing the lower end portion into contact with the ground surface. Lower the above clamping device until
Thereafter, the cone with the weight is allowed to freely fall by releasing the engagement of the cone with the cone with the weight, so that the falling height of the cone with the weight is accurately set. Can be. In addition, the drop height can be set in an extremely short time.

Therefore, according to the present invention, the density of the ground can be accurately measured in a short time.

After the cone with the weight has fallen into the ground by free fall, it is necessary to return the cone with the weight, the clamp device, and the height setting member to their original positions. This operation can be performed in a relatively short time even if the operator manually performs the operation, and even if the return operation time is added, the ground density measurement time is the same as when the conventional measurement method is used. However, as described in claim 2, after the ground penetrates due to the free fall of the cone with the weight, the clamp device is lowered. After the engagement with the cone with the weight, the clamp device is raised to the original position, and the height setting member is raised to the original position. be able to. Further, by adopting such a configuration, the operator can be released from the force of lifting the cone with the weight.

In the present invention, in order to accurately set the drop height of the cone with the weight, the lower end portion of the height setting member is brought into contact with the ground surface to set a drop reference position and to set the drop reference position. The clamp device is lowered to a reference position. As a specific configuration, as described in claim 3, the height setting member is provided with a projection for setting the drop reference position, If the clamp device is provided with a height setting switch for stopping the drive of the first lifting / lowering drive device by coming into contact with the projection when the clamp device is lowered to the drop reference position, a simple configuration is provided. The falling height of the cone with a weight can be set accurately.

Further, in the above-mentioned configuration, if the clamping device and the guide rail for guiding the lifting and lowering of the cone with the weight are provided, the falling of the cone with the weight can be achieved. Since the posture can be stabilized, the accuracy of measuring the acceleration when the ground penetrates can be further improved, and a series of operations for measuring the acceleration can be smoothly performed.

In this case, if the pair of guide rails is formed integrally with the height setting member, the strengths of the guide rail and the height setting member can be reduced. It is possible to increase each other, thereby further improving the measurement accuracy.

In the above configuration, the “support member” is
The specific configuration is not particularly limited as long as the configuration is such that the position is fixed relative to the ground at the time of the acceleration measurement. With the configuration mounted on the moving means that can move on the ground, the ground density can be efficiently measured at a plurality of measurement points. In this case, as long as the “moving means” can move on the ground, it may be a bogie that moves manually, or may be a vehicle equipped with a traveling drive means. The vehicle may be a towed vehicle towed by the vehicle or a vehicle whose traveling is controlled by remote control.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.

FIG. 1 is a side view showing an entire configuration of a ground density measuring apparatus according to an embodiment of the present invention, and FIG.
It is the block diagram.

As shown in FIG. 1, this ground density measuring device 10 is a vehicle-mounted device for measuring the density (compacting degree) of the ground 2 such as embankment, and is a light truck 100 (moving means).
The control unit 14 and the notebook computer 16 mounted in the operator's cab, and a battery power supply 18 mounted in the lower part of the vehicle body are provided. Then, the weighted cone 20 of the measurement unit 12 is dropped freely from a predetermined height to penetrate the ground 2, and the acceleration of the weighted cone 20 when the ground penetrates is measured, whereby the ground 2
Is to be measured.

Before explaining the detailed structure of the ground density measuring device 10, the principle of the ground density measurement by the ground density measuring device 10 will be described.

FIG. 6 is a diagram showing a model of the relationship between the depth at which the weighted cone 20 penetrates the ground 2 and the fracture surface 4 of the ground 2.

In the figure, the fracture surface 4 expands as the penetration of the cone with weight 20 progresses. At this time, the penetration resistance of the cone with weight 20 also increases.
It increases as the penetration of 0 progresses. When the weighted cone 20 further penetrates, the fracture surface 4 has a constant size, and the penetration resistance has an extreme value.

FIG. 7 is a graph showing the relationship between the penetration depth of the cone 20 with a weight and the penetration resistance.

In the figure, a portion a where the penetration resistance increases with an increase in the penetration depth indicates a property related to the internal friction angle of the ground 2, and a portion b where the penetration resistance is constant is , The properties related to the shear resistance of the ground 2. Therefore, by using the gradient of the portion a (depth gradient of the penetration resistance) and the value of the portion b (extreme value of the penetration resistance) as index values, the measurement of the density of the ground 2 (evaluation of the degree of compaction) is performed. It can be performed with high accuracy.

The penetration resistance can be easily calculated by measuring the acceleration of the cone 20 with the weight when the ground penetrates.

That is, the equation of motion of the cone 20 with the weight when the ground penetrates is represented by m (d ² x / dt ² ) + R = 0. Since is known, the penetration resistance R can be calculated by measuring the acceleration (d ² x / dt ² ).

Incidentally, the resolution of the acceleration measurement depends on the mass of the cone 20 with the weight, and the amount of penetration of the cone 20 with the weight depends on the mass of the cone 20 with the weight and its falling height. Therefore, in order to accurately measure the penetration resistance at the required depth, the cone 20
It is important to set the mass and the falling height of these to appropriate values in advance according to the soil properties of the ground 2 to be measured. Specifically, for example, the cone 20 with the weight
Is set to an appropriate value within the range of several kg to several tens of kg, and the falling height of the cone 20 with the weight is set to an appropriate value within the range of several tens to hundreds of mm.

Next, the detailed structure of the ground density measuring device 10 will be described.

As shown in FIG.
Is a DC12V power supply, which supplies power to the control box 14 and to the notebook personal computer 16 via a DC12V / DC19V inverter 22. In addition, the control box 14 outputs a drive control signal for measuring the acceleration to the measuring unit 12. further,
The measuring unit 12 includes an accelerometer 24 attached to the cone 20 with a weight and a four-
The detection signals of the two limit switches 26, 28, 30, 32 and the landing sensor 48 (these will be described later) are output to the control box 14. The notebook personal computer 16 outputs the measurement condition set value of the acceleration measurement and the operation signal at the time of the acceleration measurement to the control box 14 by an operator's key input operation or the like. Analysis, recording, and screen display of the acceleration data to be performed are performed.

As shown in FIG. 1, the measuring unit 12
Are a cone 20 with a weight, a clamp device 34 that is detachably connected to the cone 20 with a weight, a first lifting / lowering drive device 36 that moves the clamp device 34 up and down, and a front of the clamp device 34. A height setting member 38 extending in the vertical direction in the vicinity, a second lifting / lowering drive device 40 for raising / lowering the height setting member 38, a support member 42 for supporting the first and second lifting / lowering drive devices 36, 40, The apparatus includes a clamp device 34 and a pair of guide rails 44 for guiding the lifting and lowering of the cone 20 with the weight.

FIG. 3 is an enlarged view of a main part of FIG. 1 showing the measuring unit 12 in detail, and FIG.

As shown in these figures, the cone with a weight 20 includes a cone portion 20a having a downward conical shape, a shaft portion 20b extending upward from the cone portion 20a, and a shaft portion 2a.
0b, and a pair of guide support portions 20d provided on both sides of the weight portion 20c.
And an engagement pin 20e extending upward from the weight 20c.
And is provided. Each of the guide supporting portions 20d has a built-in linear bearing so that the weighted cone 20 can be moved up and down with respect to the pair of guide rails 44 without sliding resistance. The above-described accelerometer 24 (see FIG. 2) is attached to the weight 20c.

The clamping device 34 is provided with a casing 34
a in the vicinity of the lower end of the casing 34a.
A pair of clamp levers 34b rotatably supported about a pair of horizontal axes, a solenoid 34c mounted on the inner surface of the upper wall of the casing 34a so as to be located above the clamp lever 34b, and A hanging device 34d fixed to the outer surface of the wall, and 1
It has a pair of guide support portions 34e and a projecting piece 34f fixed to the outer surface of the wall thereafter.

The pair of clamp levers 34b are spring-biased such that the upper ends thereof rotate toward each other, and come into contact with the output rod of the solenoid 34c from both sides. Also, the pair of clamp levers 34b are engaged with the upper end of the engaging pin 20e of the cone with weight 20 at the lower end, and support the cone with weight 20 in a suspended state. Has become. However, when the solenoid 34c is excited and its output rod is retracted upward, the pair of clamp levers 34b rotate in a direction approaching each other, whereby the pair of clamp levers 34b and the engagement pins 2b are rotated.
0e is disengaged, and the cone with weight 20 falls naturally.

The configuration of each guide support portion 34e is the same as the configuration of each guide support portion 20d of the cone 20 with the weight.

The support member 42 supports the light truck 10
0, a frame 42a mounted and fixed to the rear of the loading platform, a frame 42b fixed to the frame 42a on the rear side of the frame 42a, and both frames 42a,
And a top plate 42c fixed to the upper surface of the top plate 42b. The first and second lifting drive devices 36 and 40 are mounted on the top plate 42c of the support member 42.

The first lifting / lowering drive device 36 includes a wire 36a connected to a hanger 34d of the clamp device 34.
And a lifting drum 36b around which the wire 36a is wound.
And a motor unit 36c for rotating the lifting drum 36b, and a cover 36d for covering them. The motor unit 36c includes a motor and a speed reduction mechanism.

The height setting member 38 includes a vertically extending rod 38a and a landing plate 38c connected to a lower end of the rod 38a via a bracket 38b.
And a drop reference position setting piece 38d (projection) attached to an intermediate position of the rod 38a. The landing plate 3 of the height setting member 38
A lower end portion of each guide rail 44 is fixed to 8c, and a hanger 38e is fixed to a portion of the landing plate 38c near the bracket 38b. The drop reference position setting piece 38d can be fixed to the rod 38a at an arbitrary position in the vertical direction with the adjusting screw 38f.

As shown in FIG. 1, the height setting member 38
The rod 38a and the guide rails 44 are bolted to a connecting plate 46 for connecting them at an upper end thereof and to the landing plate 38c for connecting them at a lower end thereof. The setting member 38 and each of the guide rails 44 are integrally formed as a frame structure. Each of the guide rails 44 is slidably supported in the vertical direction with respect to the frame 42b of the support member 42.

As shown in FIG. 3, the second lifting / lowering drive device 40 comprises a wire 40a connected to a hanging member 38e of the height setting member 38, a guide roller 40b for guiding the wire 40a, An elevating drum 40c around which the elevating drum 40c is wound, a motor unit 40d for driving the elevating drum 40c to rotate, and a cover 40e covering these
And is provided. The motor unit 40d includes a motor and a speed reduction mechanism.

4 for drive control at the time of measuring the acceleration
Of the two limit switches 26, 28, 30, 32
The limit switches 26 and 28 are respectively attached to the outer surface of the front wall and the outer surface of the lower wall of the casing 34a, and the limit switch 30 is connected to the frame 42 of the support member 42.
The limit switch 32 is attached to the lower end of the rear end face of the frame 42a of the support member 42. The landing sensor 48 is attached to the lower surface of the landing plate 38c of the height setting member 38.

FIG. 5 is a side view of the measuring unit 12 for explaining the procedure for measuring the ground density by the ground density measuring apparatus 10.

First, the above-mentioned measuring unit 12 is shown in FIG.
The light truck 1 is held in the measurement standby position shown in FIG.
00 by moving the measuring unit 12
Is set above the measurement point on the ground 2.

In this state, when the operator performs a measurement start input operation on the notebook personal computer 16, the second lifting / lowering drive device 40 starts driving as shown in FIG. Then, the setting member 38 is lowered. Due to this lowering, the landing plate 38c of the height setting member 38
Comes into contact with the surface of the ground 2, the landing plate 3
The landing sensor 48 attached to 8c is turned on, and the driving of the second lifting / lowering drive device 40 is stopped, whereby the drop reference position is set. The drop reference position determines the drop height of the cone 20 with the weight as described later, and adjusts the fixing position of the drop reference position setting piece 38d with respect to the rod 38a of the height setting member 38. By doing so, it is set at a predetermined position in advance.

In conjunction with the turning-on operation of the landing sensor 48, as shown in FIG.
6 starts driving to lower the clamp device 34. When the limit switch 26 (height setting switch) attached to the clamp device 34 comes into contact with the drop reference position setting piece 38d and is turned on by this lowering, the driving of the first lifting / lowering drive device 36 is stopped. As a result, the clamp device 34 is set at the drop reference position. When set to the drop reference position, the height of the lower end point of the cone portion 20a of the cone 20 with the weight from the surface of the ground 2 is set to a predetermined drop height h.

Thereafter, when the operator performs a drop input operation on the notebook personal computer 16, the solenoid 34c of the clamp device 34 is excited and the clamp device 3 is turned on.
4 is disengaged from the engaging pin 20e of the cone 20 with the weight, whereby the cone 20 with the weight falls naturally as shown in FIG. The portion 20a penetrates the ground 2. At this time, the accelerometer 24 measures the acceleration of the cone 20 with the weight at the time of penetrating the ground, and outputs the measured data to the control box 14. And
This measurement data is automatically taken into the notebook computer 16 by a pre-trigger method, and the notebook computer 1
In step 6, the index calculation result is displayed on the screen and the measurement result is recorded in the memory. This measurement data processing is performed in a very short time.

When the measurement data processing is completed, as shown in FIG. 9E, the first lifting drive device 36 starts driving again, and the clamp device 34 is connected to the lower limit mounted on the lower surface thereof. The switch 28 contacts the upper surface of the cone 20 with the weight and is lowered to a position where it is turned on. At this time, the engaging pin 20e of the cone 20 with the weight is used.
Are a pair of clamp levers 34b of the clamp device 34.
Between the two clamp levers 34b against the urging force of the spring.
4b.

In conjunction with the turning-on operation of the limit switch 28, as shown in FIG. 9F, the first lifting / lowering drive device 36 starts to drive in the reverse direction, and the clamp device 34 is turned on. Along with the cone 20 with the weight, the projecting piece 34f attached to the rear surface of the clamp device 34 comes into contact with the limit switch 30 attached to the frame 42b of the support member 42 and moves up to a position where the limit switch 30 is turned on.

Further, in conjunction with the turning-on operation of the limit switch 30, as shown in FIG. 9G, the second lifting / lowering drive device 40 starts driving in the reverse direction, and the height setting member 38 Together with the pair of guide rails 44 until the front end of the landing plate 38c of the height setting member 38 comes into contact with the limit switch 32 attached to the frame 42a of the support member 42 to turn it on. Then, the measurement unit 12 is returned to the original measurement standby position shown in FIG.

With the above-described series of operations, the ground density measurement at the above measurement point is completed.

Thereafter, by moving the light truck 100 and setting the measuring unit 12 above the next measuring point on the ground 2, the ground density can be measured in the same manner as described above.

The ground density measuring operation can be sequentially performed for each operation by pressing the switch button 14a of the control box 14.

As described in detail above, the ground density measuring apparatus 10 according to the present embodiment drops the cone 20 with the weight, penetrates the ground 2, measures the acceleration at that time, and analyzes the acceleration. The density of the ground 2 is measured by the above method. As a specific configuration for measuring the acceleration, the height setting member 38 is lowered so that the lower end portion thereof is brought into contact with the surface of the ground 2. After setting the drop reference position, the clamp device 34 is moved to the drop reference position.
Is lowered, and then the engagement of the clamp device 34 with the cone 20 with the weight is released, so that the cone 20 with the weight is allowed to fall freely. The height h can be set accurately. In addition, the drop height can be set in an extremely short time.

Further, after the ground density measuring device 10 penetrates into the ground due to the free fall of the cone 20 with the weight, the clamp device 34 is lowered and the cone 20 with the weight is lowered.
Then, the clamp device 34 is raised to the original position, and the height setting member 38 is raised to the original position. 34 and the height setting member 3
8 can be returned to the original position in a very short time. Further, the operator can be released from the force of lifting the cone 20 with the weight.

According to this embodiment, the density of the ground can be accurately measured in a short time of about 1 to 2 minutes. In addition, even if the return operation is performed manually, the entire measurement time can be reduced to about several minutes.

In the present embodiment, the falling height h of the cone 20 with the weight is adjusted by the contact between the drop setting position setting piece 38d and the limit switch 26 of the clamp device 34 on the height setting member 38. Is set, the drop height h can be accurately set with a simple configuration.

Further, in the present embodiment, the lifting and lowering of the clamping device 34 and the cone 20 with the weight is guided by the pair of guide rails 44, so that the cone 20 with the weight is The falling posture can be stabilized, whereby the accuracy of measuring the acceleration when the cone with weight 20 penetrates the ground can be further improved, and a series of operations for measuring the acceleration can be performed smoothly. Moreover, the pair of guide rails 4
4 is integrally formed with the height setting member 38 in a frame shape, so that the strengths of the guide rails 44 and the height setting member 38 can be mutually increased, thereby further increasing the measurement accuracy. be able to.

The ground density measuring apparatus 10 according to this embodiment is mounted on the light truck 100,
By appropriately traveling the light truck 100,
The ground density measurement can be efficiently performed on a plurality of measurement points on the ground 2.

In the above-described embodiment, the falling of the cone 20 with the weight is performed by an operator's drop input operation on the notebook personal computer 16, but the drop reference position setting frame of the limit switch 26 is set. It is also possible to adopt a configuration in which the robot automatically falls in conjunction with the on operation by the contact with 38d.

In the above-described embodiment, the fixed position of the drop reference position setting piece 38d with respect to the rod 38a is adjusted by the adjusting screw 38f, but is adjusted by remote control from the control box 14. It is also possible.

[Brief description of the drawings]

FIG. 1 is a side view showing an overall configuration of a ground density measuring apparatus according to an embodiment of the first invention of the present application.

FIG. 2 is a block diagram showing the overall configuration of the above-mentioned ground density measuring device.

FIG. 3 is an enlarged view of a main part of FIG. 1, showing in detail a measuring unit of the ground density measuring device.

4 is a view in the direction of arrow IV in FIG. 3;

FIG. 5 is a side view of the measurement unit, illustrating a procedure of measuring the ground density by the ground density measurement device.

FIG. 6 is a diagram showing a model of the relationship between the depth at which the cone with the weight of the measurement unit penetrates the ground and the fracture surface of the ground.

FIG. 7 is a graph showing the relationship between the penetration depth of the cone with a weight and the penetration resistance.

[Explanation of symbols]

 2 Ground 4 Fracture Surface 10 Ground Density Measuring Device 12 Measuring Unit 14 Control Box 14a Switch Button 16 Notebook PC 18 Battery Power 20 Cone with Weight 20a Cone 20b Shaft 20c Weight 20d Guide Support 20e Engagement Pin 22 Inverter 24 Accelerometer 26 Limit switch (height setting switch) 28, 30, 32 Limit switch 34 Clamping device 34a Casing 34b Clamp lever 34c Solenoid 34d Hanging tool 34e Guide support 34f Projection 36 First lifting drive 36a Wire 36b Lifting drum 36c Motor unit 36d Cover 38 Height setting member 38a Rod 38b Bracket 38c Landing plate 38d Drop reference position setting frame (projection) 38e Suspension tool 38f Adjustment Alignment screw 40 Second lifting / lowering drive device 40a Wire 40b Guide roller 40c Lifting drum 40d Motor unit 40e Cover 42 Support member 42a, 42b Frame 42c Top plate 44 Guide rail 46 Connecting plate 48 Landing sensor 100 Light truck (moving means)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-196838 (JP, A) JP-A-5-230820 (JP, A) JP-A-5-239819 (JP, A) 135334 (JP, U) Registered utility model 3027598 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 1/00-1/08

Claims (6)

(57) [Claims] An apparatus for measuring the density of the ground by dropping a cone with a weight from a predetermined height to penetrate the ground and measuring the acceleration of the cone with the weight at the time of the ground penetration. A clamp device that is detachably connected to the cone with a weight, a first lifting / lowering drive device that moves the clamp device up and down, a height setting member that extends in the vertical direction near the clamp device, A second lifting device for raising and lowering the height setting member, and a support member for supporting the first and second lifting and lowering devices. The height setting member is lowered to lower the height setting member. After setting the drop reference position by bringing the lower end portion into contact with the ground surface, lower the clamp device to the drop reference position, and then engage the clamp device with the cone with the weight. And it is configured so as to free fall a cone with heavy weight by dividing, soil density measurement and wherein the. 2. After penetrating the ground due to free fall of the cone with weight, lowering the clamp device to engage with the cone with weight, raise the clamp device to the original position, The ground density measuring device according to claim 1, wherein the height setting member is configured to be raised to an original position. 3. The height setting member is provided with a projection for setting the drop reference position. The clamp device contacts the projection when the clamp device is lowered to the drop reference position. The ground density measuring device according to claim 1 or 2, further comprising a height setting switch for stopping driving of the first lifting drive device. 4. The ground density measuring device according to claim 1, further comprising a pair of guide rails for guiding the clamp device and the cone with a weight to move up and down. 5. The ground density measuring apparatus according to claim 4, wherein said pair of guide rails are formed integrally with said height setting member. 6. The ground density measuring apparatus according to claim 1, wherein said support member is mounted on a moving means capable of moving on said ground.