JP3352812B2 - Method and apparatus for measuring ground hardness - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the hardness index of a ground used for a foundation work machine such as an earth auger or an earth drill.

[0002]

2. Description of the Related Art Conventionally, when performing a foundation work on a building or the like, a boring survey is performed in advance to obtain a reliable bearing force of a pile constructed by a foundation construction machine such as an earth auger, and based on a result of the boring survey. A columnar map is created, and the required length of the pile to be mixed into the foundation ground is determined based on this. During excavation, the load current of the auger motor was considered to be proportional to the hardness of the ground, and the load current was compared with the soil column diagram to determine whether the pile reached the foundation ground. However, since the load current of the auger motor is affected not only by the hardness of the ground but also by the excavation speed, it is difficult to accurately know the hardness of the ground only by the load current.

For this reason, in the apparatus described in Japanese Patent Application Laid-Open No. 63-67319, a value ΔI / I obtained by dividing the increase ΔI of the load current of the auger motor from the no-load state by the auger excavation speed v.
Focusing on the point that v is proportional to the hardness of the ground, the value ΔI /
The v is always calculated and displayed so that the hardness of the ground can be grasped. When a hydraulically driven auger motor is used, the amount of increase ΔT in torque from the no-load state of the motor and the motor speed N are detected instead of ΔI, and the hardness is determined based on ΔT · N / v.

[0004]

In the apparatus described in the above-mentioned publication, when the excavation speed v decreases to near 0, ΔI / v and ΔT · N / v become infinite, so that the hardness of the ground can be accurately grasped. Can not.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and a method of measuring the hardness of a ground capable of accurately detecting the ground strength during actual excavation and improving the efficiency of construction. And to provide a device.

[0006]

(1) One embodiment of the present invention will be described with reference to FIGS. 2 and 4. According to the first embodiment, the hardness of the ground is detected by detecting the excavation state of the drive unit 4. The method is applied to a method for measuring the hardness of the ground, which calculates an index correlated to The purpose described above is to detect the excavation depth (steps S2 and S8), and based on the excavation state of the driving device 4,
This is achieved by calculating the excavation energy per unit volume while the excavation speed changes by a fixed amount as a value correlated with the hardness of the ground (steps S4 to S10). (2) Explaining in association with FIG. 1 and FIG. 2, the invention of claim 2, the excavating member 5 driven by the driving device 4,
6 is applied to a ground hardness measuring device used for a drilling device for drilling a hole in the ground, and the drilling depth is a fixed amount based on the drilling depth detecting means 11 for detecting the drilling depth and the drilling state of the driving device 4. The above-mentioned object is achieved by having a ground hardness index calculating means for calculating the excavation energy per unit volume during the change as an index correlated to the hardness of the ground. (3) The invention of claim 3 is the apparatus for measuring ground hardness according to claim 2, wherein the ground hardness index calculating means comprises:
Load detection means 9, 10, 1 for detecting the drive load T of
3, a digging depth detecting means 11 for detecting a digging depth D by the digging members 5 and 6, a rotational speed detecting means 10 for detecting a rotational speed N of the driving device 4, a detected driving load T, a digging depth D, Excavation area A by rotation speed N and excavation members 5 and 6
The excavation energy per unit volume while the excavation depth changes by a certain amount is defined as an index H correlated to the hardness of the ground, and H = {(T × N × Δt)} / A × L Δt is a sampling time of T, N, and L. The arithmetic means 13 is provided with a calculating means 13 for calculating L from a fixed amount of excavation depth calculated from the excavation depth D. (4) According to a fourth aspect of the present invention, in the ground hardness measuring apparatus of the second or third aspect, display means 15 and 17 for displaying a calculation result of the hardness index calculating means 13 are provided.

[0007]

According to the first and second aspects of the present invention, the excavation state per unit volume during a constant change in the excavation depth correlates with the hardness of the ground from the excavation state of the drive unit 4 and the detected excavation depth. Is calculated as According to the third aspect of the present invention, the driving load T detected by the driving load detecting means 9, the excavation depth D of the excavating members 5 and 6 detected by the excavation vibration detecting means 11, and the driving device 4 detected by the rotation speed detecting means 10. The index H correlated to the hardness of the ground is calculated by the hardness index calculating means 13 from the following equation based on the rotation speed N of the above and the excavated area A of the excavated members 5 and 6. H = {(T × N × Δt)} / A × L where Δt is a sampling time of T, N, and L L is a constant amount of excavation depth calculated from the excavation depth D. The calculation results of the exponent calculation means 13 are displayed on the display means 15 and 17.

[0008] In the means and means for solving the above-mentioned problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First Embodiment FIG. 2 shows an example of a machine for foundation work provided with an earth auger to which the present invention is applied. The machine 1 for foundation work
An auger unit 2 and an auger unit elevating chain 3 that suspends the auger unit 2 are provided. The auger unit 2 includes a digging mechanism 4 and an auger screw 5.
And an excavating head 6 attached to the tip of the auger screw 5. The excavating mechanism 4 includes a hydraulically driven auger motor (not shown), transmits rotation of the auger motor to the auger screw 5, and rotates the auger screw 5 and the excavating head 6.

FIG. 1 shows a block diagram of a first embodiment of the present invention. The excavation torque detector 9 detects the excavation torque from the inlet pressure of the auger motor, the rotation number detector 10 detects the rotation number of the auger screw, and the depth detector 11 determines the excavation position of the excavation head 6. It is to detect. Excavation torque detector 9, rotation speed detector 10
The detection result of the depth detector 11 is applied to the A / D conversion unit 12. The A / D conversion unit 12 includes a multiplexer and an A / D converter (not shown), and converts analog signals from the excavation torque detector 9, the rotation speed detector 10, and the depth detector 11 into digital signals. The microcomputer unit 13 calculates and outputs a ground hardness index H, as described later, based on the excavation torque, rotation speed, and depth digitized by the A / D conversion unit 12. Although not shown, the microcomputer unit 13 includes a microprocessor unit MPU for performing calculations and controls, and a read-only memory ROM storing a processing procedure program for the microprocessor unit MPU.
And a random access memory RAM for storing input data and calculation results.

The D / A converter 14 receives the output of the operation result of the hardness index H of the ground by the microcomputer unit 13, and the D / A converter 14 outputs the operation result output from the microcomputer unit 13. Is converted to an analog value. The D / A converter 14 is connected to a meter 15 and a recorder 16.
Indicates the D / A conversion result of the ground hardness index H by the D / A converter 14, and the recorder 16 indicates the D of the ground hardness index H.
Record the / A conversion result. Further, a printer 17 is connected to an output port of the microcomputer unit 13, and the printer 17 records an operation result of the microcomputer unit 13.

FIG. 3 is a view showing a state in which the auger unit 2 is lowered at a predetermined speed and the auger motor is operated to rotate the auger screw 5 and the excavating head 6 to excavate the ground. In FIG. 3, assuming that a hardness index (mainly ground shear stress) representing the hardness of the ground is ΔH, the excavation cut width is d, and the excavation width is b, the excavation force F is

## EQU1 ## F∝ΔH · d · b (1) Since the excavation cut width d corresponds to the excavation amount per rotation of the auger screw, if the excavation speed of the auger unit 2 is v and the rotation speed of the auger screw 5 is N, the expression (1) becomes

F２ΔH ・ v ・ b / N (2)

If the digging width b is equivalent to the radius of the auger screw 5, the digging area is πb ² , and if the digging area is A, the equation (2) becomes

## EQU3 ## F∝ΔH · v · A / N (3) The excavation speed v of the auger unit 2 corresponds to the excavation amount per unit time. Assuming that the unit time is Δt and the excavation amount per unit time is ΔL, the equation (3) becomes

F４ΔH · A · ΔL / Δt · N (4) The relationship between the excavation torque T and the excavation force F is

## EQU5 ## T し F (5), and the excavation torque T represents excavation energy. Therefore, from Equations (4) and (5), the ground hardness index ΔH per unit time is:

ΔH = T · N · Δt / ΔL · A (6)

In order to obtain the hardness index H of the ground for each certain excavation depth L, the excavation energy required to excavate the excavation depth L is an integrated value of the excavation energy from 0 to L. Can be expressed as Therefore, the hardness index H of the ground at each excavation depth L is given by:

H = Σ (T · N · Δt) / A · L (7) Therefore, the hardness index H of the ground for each excavation depth L is calculated by detecting the excavation torque T of the auger motor, the auger rotation speed N, and the depth D of the excavation head.
Note that as T, _a value (T _a −T ₀ ) obtained by subtracting the torque T ₀ at the time of no load (during no excavation) from the actual torque Ta at the time of excavation is used.

Next, the operation of the measuring apparatus of the first embodiment will be described.
The processing procedure in the microcomputer unit 13 will be described with reference to FIG. The microcomputer unit 13 starts the following processing upon receiving the excavation command. In step S1, the ground hardness index H and the excavation energy E held on the built-in memory of the microcomputer unit 13 are first cleared to zero. Then enter the depth D In step S2, in step S3, replacing the depth D which is held on the memory at this point in the drilling start depth D _0. In step S4, the excavation torque T is input, and in step S5, the auger rotation speed N is input. In step S6, the excavation torque T and the rotation speed N
And the predetermined sampling time Δt, the work amount ΔE of the excavator is calculated. In step S7, the work amount ΔE of the excavator calculated in step S6 is added to the excavation energy E. Note that Δt is set in advance as an approximate time required for one process from step S4 to step S9.

In step S8, the current depth D is input to update the stored value in the internal memory. Step S9, taking the difference between the drilling start depth D ₀ is replaced with the depth D and the step S3 input in step S8 (D-D _0), is compared with the depth L determines the hardness of the ground. When it is determined that the difference between the calculation depth D and the excavation start depth D ₀ is equal to or greater than the depth L, step S10 is performed to calculate the ground hardness index H.
Proceed to. When the difference between the operation time of the depth D and drilling start depth D ₀ is determined to be smaller than the determination depth L of the hardness of the ground, the process returns to step S4, and repeats the processing of step S4~ step S9. In Step 10, the hardness index H of the ground is calculated from the excavation energy E, the excavation area A, and the unit depth L,
In step S11, the calculation result of step S10 is output.

As described above, the processing of steps S1 to S11 is repeated to measure the hardness index H of the ground. The calculation result of the ground hardness index H is recorded on the printer 17 and is also converted by the D / A converter 14 into an analog signal and recorded on the meter 15 and the recorder 16. Since there is no v in the denominator, it can be determined even in the region of v = 0.

Second Embodiment Next, a second embodiment of the ground hardness measuring apparatus according to the present invention will be described with reference to FIG. 4 and FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
In the second embodiment, the microcomputer unit 13
The D / A converters 14 and 18 convert the hardness index H and the excavation depth D of the ground outputted from the XY recorder 1 into analog data.
9 is added. And XY recorder 1
9 graphically records the ground hardness index H with respect to the excavation depth D as shown in FIG.

As described above, in the second embodiment, the ground hardness index H calculated by the microcomputer unit 13 is graphed together with the excavation depth D and recorded in the XY recorder 19, so that the driver is able to excavate the ground while excavating. In addition, it is possible to more accurately grasp the hardness index H of the ground at a predetermined excavation depth. This enables reliable and clear construction management. The recording example shown in FIG. 5 is consistent with the boring result that there is a slightly hard layer at 2 m from the surface of the ground and a hard support layer at about 8 m. In the above, the auger motor is described as a hydraulic motor, but the auger can be driven by an electric motor. In this case, (TNN.DELTA.t) of the work amount .DELTA.E of the excavator may be replaced with (K.VI..DELTA.t). Here, the drive voltage value of the V electric motor, I hydraulic motor minus load current I ₀ of the no-load state from the load current I _a during excavation (I _a -I _0), K is the work rate of the electric motor This is a coefficient for converting the power into the power.

The present invention can be applied to a digging device for digging the ground such as an earth drill other than the earth auger. In the above embodiment, the excavating mechanism 4 rotates the driving device, the auger screw 5 and the excavating head 6 rotate the digging member, the digging torque detector 9 rotates the driving load detecting means, the depth detector 11 rotates the digging depth detecting means, and The number detector 10 constitutes the rotational speed detecting means, and the meter 15, the printer 17, and the XY recorder 19 constitute the display means.

[0021]

As described above, according to the present invention,
Since the excavation energy per unit volume at a certain amount of excavation depth is obtained as a value correlated with the hardness index of the ground, the excavation speed which could not be measured by the conventional method, even in the ground where the excavation speed is 0 or close to it, The hardness of the ground can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of a hardness index measuring device according to the present invention.

FIG. 2 is a schematic side view of a machine for foundation work.

FIG. 3 is a diagram for explaining excavation force.

FIG. 4 is a flowchart showing a flow of processing of the hardness index measuring device.

FIG. 5 is a block diagram of a second embodiment of the present invention.

FIG. 6 is a diagram showing measurement results recorded by an XY recorder according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 foundation work machine 2 auger unit 4 excavating mechanism 5 auger screw 6 excavating head 9 excavating torque detector 10 rotation speed detector 11 depth detector 13 microcomputer unit 15 meter 16 recorder 17 printer 19 XY recorder

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 3/40 E02D 1/02 E21B 47/04 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A method for measuring the hardness of a ground, which detects an excavation state of a driving device and calculates an index correlated with the hardness of the ground, comprising: detecting an excavation depth; A method for measuring the hardness of a ground, wherein the excavation energy per unit volume during a certain amount of change in the depth is calculated as the index. 2. A ground excavation member driven by a driving device.
For measuring the hardness of the ground used in drilling equipment for drilling holes
And Depth detection means for detecting the excavation depth; Excavation depth changes by a certain amount based on the excavation state of the drive unit
The excavation energy per unit volume during
Ground hardness index calculating means for calculating as an index correlated with
A soil hardness measuring device characterized by having: 3. The apparatus for measuring the hardness of ground according to claim 2.
hand, The ground hardness index calculation means, Drive load detecting means for detecting a drive load T of the drive device
When, Excavation depth detection for detecting excavation depth D by the excavation member
Means, Rotation speed detection means for detecting a rotation speed N of the driving device; The detected drive load T, excavation depth D, rotation speed N, and
Based on the excavated area A of the excavated member,
The excavation energy per unit volume during the quantitative change
As an index H correlated to the hardness of the board, H = {(T × N × Δt)} / A × L Where Δt is the sampling time of T, N, L L is a constant amount of excavation depth calculated from excavation depth D Characterized by comprising calculating means for calculating from the ground
Hardness measuring device. 4. A measuring apparatus according to claim 2 or 3 soil hardness according, soil hardness measuring apparatus characterized by comprising display means for displaying the calculation result of the stiffness index calculating means.