JP2019065617A - Rock property determination apparatus - Google Patents

Abstract

To provide an inexpensive rock property determination apparatus which can confirm the properties of the rock in the present cutting face.SOLUTION: A rock property determination apparatus 1 according to the present invention includes a current sensor 2 for detecting a current flowing through a motor M for driving a cutter head C provided at the tip of a boom B of a free section excavator E and a determination unit 3 for determining the property of the rock in the cutting face which cutter head C excavates on the basis of the current detected by the current sensor 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rock quality determination apparatus.

  Although there are several types of excavators that perform tunneling, free-section excavators are used to excise the cross-section into any shape. For example, the free cross section excavating machine has a cutter head at the tip of a boom mounted so as to be capable of turning in the left and right direction and raising and lowering in the up and down direction with respect to the traveling body. Move and dig.

  In the case of the tunnel excavation work, since any part of the exposed face is cut, unexpected changes in the ground conditions may cause a sudden spring, which may cause the face to fall or run off. In addition, when digging a hard ground, the load on the free cross-section drilling machine is high, so the drilling machine may break down and stop.

  Therefore, in the case of using a free cross section drilling machine, it is important to grasp the strength of the bedrock in the face in order to conduct tunnel excavation safely and efficiently. Conventionally, the strength of the forward rock was predicted in advance by drilling speed analysis, advanced boring, elastic wave exploration in a well, etc. However, these preliminary investigations are very expensive.

  Therefore, there is a proposal of a measurement system that measures the hardness of the rock at low cost. In this measurement system, the cutter head cuts the face vertically by a predetermined depth, and the amount of power consumed by the motor driving the cutter head The hardness of the rock is measured at (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 11-44622

  In the above-mentioned measurement system, since the hardness of the bedrock is measured by the amount of work when the cutter head excavates the bedrock, the behavior of the bedrock can not be determined in a timely manner while the face is being excavated. Further, in order to detect the amount of electric power of the motor, a plurality of sensors, that is, a current sensor and a voltage sensor, are required, which is expensive.

  Therefore, the present invention is to provide an inexpensive rock quality determination apparatus capable of confirming the nature of the rock quality in the current face.

  The rock quality determination apparatus according to the present invention includes a current sensor for detecting a current flowing through a motor for driving a cutter head provided at a tip of a boom of a free cross section drilling machine, a peak value which is an amplitude of a waveform of the current of the motor, and a current And a determination unit that determines the property of the rock in the face where the cutter head excavates based on the average value of the absolute value of the current value or the effective value of the current. In the rock quality determination apparatus configured as described above, since the property of the rock in the face can be determined from the current flowing to the motor, the property of the rock currently being excavated can be grasped.

  Specifically, in the determination unit, the crest value in the current waveform of the motor is higher than the reference crest value, and the average value of the absolute values of the current is lower than the reference average value, or the effective value of the current is greater than the reference effective value. If it is low, it is judged that the rock is composed of hard rock, the peak value in the motor current waveform is lower than the reference peak value, and the average absolute value of the current is higher than the reference average or the current If the effective value is lower than the reference effective value, it may be determined that the rock is composed of soft rock.

  Furthermore, another rock quality determination apparatus according to the present invention includes a current sensor for detecting a current flowing in a motor for driving a cutter head provided at a tip of a boom of a free cross section drilling machine, and vibration due to torque fluctuation of the current motor. And a determination unit that determines the property of the rock in the face where the cutter head excavates based on the frequency of the component and the average value of the absolute value of the current or the effective value of the current. In the rock quality determination apparatus configured as described above, in addition to the hardness of the rock, the magnitude of the crack included in the rock can also be determined.

  Specifically, the determination unit determines that the frequency of the vibration component of the current waveform caused by the torque fluctuation of the motor is higher than the reference frequency, and the average value of the absolute values of the current is lower than the reference average value or the effective value of the current Is lower than the reference effective value, it is determined that the bedrock is a hard rock having a large crack, the frequency is higher than the reference frequency, and the average value is higher than the reference average value or the effective value is the reference effective value If higher, it is determined that the bedrock is a hard rock having a small crack, the frequency is lower than the reference frequency, and the average value is higher than the reference average value or the effective value is higher than the reference effective value. It may be determined that the rock is soft rock.

  According to the rock quality determination apparatus of the present invention, it is possible to confirm the property of the rock in the current face at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view of the free cross-section drilling machine which mounts the rock quality determination apparatus in one Embodiment. (A) is the figure which showed the current waveform at the time of excavating a hard bedrock. (B) is a figure which showed the current waveform at the time of excavating a soft bedrock. It is a figure explaining the 1st example of the determination procedure of the hardness of the rock in the rock property determination apparatus of one Embodiment. It is a figure explaining the 2nd example of the determination procedure of the hardness of the rock in the rock property determination apparatus of one Embodiment. It is a figure showing the current waveform at the time of excavating a rock with a large crack and a rock with a small crack. It is a figure explaining the 3rd example of the determination procedure of the hardness of the rock in the rock property determination apparatus of one Embodiment. It is a figure explaining the 4th example of the judgment procedure of the hardness of the rock in the rock quality judgment device of one embodiment.

  Hereinafter, the present invention will be described based on the embodiments shown in the drawings. As shown in FIG. 1, the rock quality determination apparatus 1 according to one embodiment detects a current flowing to a motor M driving a cutter head C provided at the tip of a boom B of a free cross-section drilling machine E excavating a face. A current sensor 2 and a determination unit 3 which determines a property of a rock in a face where a cutter head C excavates based on a current detected by the current sensor 2 is configured.

  Hereinafter, each part of the rock quality determination apparatus 1 will be described in detail. First, the free cross section drilling machine E to which the rock quality determination device 1 is applied can be mounted for traveling body W provided with crawlers and turning in the lateral direction and elevation in the vertical direction with respect to the traveling body W It comprises a boom B which can be extended and retracted, a cutter head C rotatably mounted on the tip of the boom B, and a motor M for rotationally driving the cutter head C.

  The free cross-section drilling machine E configured in this way drives the boom B to rotate the cutter head C by the motor M and arranges the cutter head C to a position where digging of the face is desired, and the cutter head C is substantially constant. The rock face of the face is excavated by pressing it against the face with a pressure of The motor M is configured to rotate the cutter head C by receiving power supply of a constant voltage from a power supply (not shown).

  Subsequently, the rock quality determination apparatus 1 will be described. The current sensor 2 sequentially detects the current flowing through the motor M at a predetermined sampling cycle, and outputs the detected current to the determination unit 3.

  The determination unit 3 receives the input of the current detected by the current sensor 2 and determines the property of the rock in the face where the cutter head C is cutting. The determination unit 3 may receive an input of the current from the current sensor 2 by wire communication, or may be by wireless communication. Moreover, although the determination part 3 may be installed in the free cross-section drilling machine E, you may be installed in the management office which manages tunnel construction.

  Here, the cutter head C is biased by the hydraulic cylinder (not shown) from the boom B side while the free cross-section drilling machine E is excavating, and is pressed against the face with a substantially constant pressing force to obtain a bedrock of the face Excavate. The cutter head C is constantly rotationally driven by receiving resistance from the rock during drilling, and when the resistance acting on the cutter head C from the rock changes, the output torque of the motor M driving the cutter head C also fluctuates. . As described above, when excavating the face, the motor M receives the power supply of a constant voltage from the power supply (not shown) and rotationally drives the cutter head C. Therefore, when the torque fluctuates, it flows in the winding of the motor M The current also fluctuates.

  When excavating a hard bedrock with a cutter head C, the cutter head C is less likely to bite into the bedrock, so slippage is likely to occur between the cutter head C and the bedrock. Therefore, the resistance that the cutter head C receives from the rock during drilling tends to be low on average, so the average torque of the motor M also becomes low, as shown in FIG. The average of the absolute values also decreases. In addition, when the bedrock is hard, when the bedrock is excavated with a cutter head C, a large block of rock is likely to be detached from the bedrock. When such a large block of rock is detached from the rock, a large resistance acts on the cutter head C before the rock is detached from the rock, and the resistance acting on the cutter head C is significantly reduced after the rock is detached from the rock . Therefore, before and after the rock is peeled from the rock, the torque of the motor M fluctuates significantly, and therefore, as shown in FIG. 2A, the current flowing through the motor M also fluctuates significantly. Therefore, when the rock which is being excavated by the cutter head C is hard, the peak value of the current waveform of the motor M, that is, the amplitude of the current waveform tends to increase.

  On the other hand, when excavating a soft bedrock with the cutter head C, the cutter head C tends to bite into the bedrock, so the resistance that the cutter head C receives from the bedrock tends to be high on average. Therefore, as shown in FIG. 2 (B), the average torque of the motor M becomes high, and the average value of the absolute value of the current flowing through the motor M also becomes high. In addition, when the bedrock is soft, when the bedrock is excavated with the cutter head C, the rock of the particle is easily removed from the bedrock because the bedrock is easily scraped. As described above, when a fine stone is scraped from the rock by the digging of the cutter head C, the variation in resistance to which the cutter head C is subjected is smaller than that in the case of digging a hard rock. Therefore, as shown in FIG. 2B, when the rock which is being excavated by the cutter head C is soft, the peak value of the current waveform of the motor M tends to be small.

  As mentioned above, the determination part 3 determines the property of a rock based on the average value of the absolute value of the electric current which flows into the motor M, and the peak value of the waveform of an electric current. Specifically, as shown in FIG. 3, determination unit 3 sets a reference crest value to a crest value that is an amplitude of the current waveform of motor M, and also determines an average value of absolute values of current. A reference average value is set, and the property of the rock is determined based on the comparison result of the peak value and the reference peak value, and the comparison result of the average value of the absolute value of the current and the reference average value. More specifically, when the peak value in the current waveform of the motor M is higher than the reference peak value and the average value of the absolute values of the current is lower than the reference average value, the determination unit 3 determines that the bedrock is hard rock If the crest value in the waveform of the current is lower than the reference crest value and the average value of the absolute values of the current is higher than the reference average value, it is determined that the rock is composed of soft rock . The reference peak value serving as a reference for determining the magnitude of the peak value of the current waveform and the reference average value serving as a reference for determining the magnitude of the average value of the absolute values of the current The data obtained by drilling and the results of the hardness survey of the rock may be taken into consideration. As for the peak value, an average value of the amplitude of the current waveform or an average value of the amplitude extracted by extracting the determined number of large ones in the current waveform may be used as the peak value, or the maximum amplitude in the current waveform The peak value may be used.

  In this example, the rock quality is judged to be either hard rock or soft rock, but the hardness of the rock is lower as the average value of the absolute values of the current is lower and the wave height of the current is higher. The higher the average value of the absolute values of the current and the lower the peak value of the current waveform, the lower the hardness of the rock. Therefore, the determination unit 3 may output the hardness of the rock as a numerical value based on the average value of the absolute values of the current and the peak value of the waveform of the current in the determination of the property of the rock.

  Although not shown, when excavating a hard bedrock with a cutter head C, the effective value of the current is lowered as well as the average value of the absolute values of the current flowing through the motor M, and a soft bedrock is excavated with a cutter head C In this case, as well as the average value of the absolute values of the current flowing to the motor M, the effective value of the current also becomes high. Therefore, the determination unit 3 uses the effective value of the current instead of the average value of the absolute value of the current flowing through the motor M as a determination material to be used together with the peak value of the current waveform in the determination of hardness of the rock. Good.

  In this case, the determination unit 3 may determine the property of the rock based on the effective value of the current flowing through the motor M and the peak value of the current waveform. Specifically, as shown in FIG. 4, determination unit 3 sets a reference crest value for the crest value which is the amplitude of the current waveform of motor M, and also determines a reference effective value for the effective value of current. Is determined, and the property of the rock is determined based on the comparison result of the peak value and the reference peak value and the comparison result of the effective value of the current and the reference effective value. More specifically, the determination unit 3 determines that the rock is made of hard rock when the wave height value of the current waveform of the motor M is higher than the reference wave height value and the effective value of the current is lower than the reference effective value. If the crest value in the waveform of the current is lower than the reference crest value and the effective value of the current is higher than the reference effective value, it is determined that the rock is composed of soft rock. The reference effective value serving as a reference for determining the level of the effective value of the current may be determined based on, for example, data obtained by excavating the rock with a real machine and the result of the hardness survey of the rock.

  In addition, although it is judged that the property of the rock is either hard rock or soft rock, the lower the effective value of the current and the higher the wave height of the current waveform, the higher the hardness of the rock and the effective of the current The higher the value and the lower the crest value of the current waveform, the lower the rock hardness. Therefore, the determination unit 3 may output the hardness of the rock in a numerical value based on the effective value of the current and the peak value of the waveform of the current in the determination of the property of the rock.

  Also, the determination unit 3 determines the property of the rock based on the average value of the absolute values of the current flowing through the motor M and the frequency of the vibration component appearing in the waveform of the current of the motor M due to the torque fluctuation. Good. When excavating a hard bedrock with cutter head C, if rock bed is excavated with cutter head C, the rock will peel off from bedrock sequentially, so resistance that cutter head C receives from bedrock will fluctuate greatly, and the cycle of torque fluctuation of motor M will also be short. . On the other hand, in the case of excavating a soft bedrock with a cutter head C, since the torque fluctuation is small, the cycle of the torque fluctuation of the motor M becomes long. As shown in FIG. 2, the frequency of the vibration component appearing in the current waveform of the motor M due to the torque fluctuation coincides with the envelope of the current waveform of the motor M. Therefore, focusing on the frequency of the vibration component appearing in the waveform of the current of the motor M due to the torque fluctuation, as shown in FIG. 2, the waveform of the current when solid rock is excavated (solid line in FIG. Of the current waveform (solid line in FIG. 2 (B)) when the frequency of the envelope (broken line in FIG. 2 (A)) excavates a soft rock is It is higher than the frequency. Therefore, the determination unit 3 examines the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M input from the current sensor 2 and determines that the rock is composed of hard rock when this frequency is high. Do. In order to obtain the envelope, for example, Hilbert transform may be used, or an envelope detector may be used. Incidentally, in order to obtain the frequency of the vibration component appearing in the waveform of the current of the motor M due to the torque fluctuation, the envelope may be determined as follows. The current is filtered by a low pass filter or a band pass filter that extracts a frequency component of a vibration component caused by torque fluctuation lower than the drive frequency of the current required to drive the motor M from the detected current of the motor M Then, the vibration component may be extracted, and the frequency may be obtained from the extracted vibration component.

  Furthermore, in the case where the rock is hard and there is a crack in the rock, the resistance that the cutter head C receives from the rock differs depending on the size of the crack, and the cutter head C becomes larger as the rock in the rock becomes larger. We found that the average value of the resistance received from the bedrock is low. Therefore, as shown in FIG. 5, a current waveform (solid line in FIG. 5) when digging a hard rock with a large crack and a current waveform (dotted line in FIG. 5) when digging a hard rock with a small crack In comparison, the larger the crack, the lower the average absolute value of the current. Therefore, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is high and the average value of the absolute values of the current is low, the judgment unit 3 is composed of hard rock containing large cracks It is determined that there is. Further, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is high and the average value of the absolute values of the current is high, the judgment unit 3 is composed of hard rock containing small cracks It is determined that there is.

  On the other hand, when excavating a soft bedrock with cutter head C, if the bedrock is excavated with cutter head C, the bedrock is easily scraped off, so that the variation in resistance that cutter head C receives from the bedrock is small. It also gets longer. That is, the frequency of the vibration component appearing in the current waveform of the motor M due to the torque fluctuation is lowered. Therefore, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M input from the current sensor 2 is low, there is a possibility that the rock is composed of soft rock. Moreover, when excavating a soft bedrock with the cutter head C, the cutter head C easily bites into the bedrock, so the average torque of the motor M becomes high, and the average value of the absolute value of the current flowing through the motor M becomes high. Therefore, when the frequency of the vibration component due to torque fluctuation appearing in the waveform of the current of the motor M is low and the average value of the absolute values of the current is high, the determination unit 3 determines that the rock is composed of soft rock. .

  From the above, the determination unit 3 determines the property of the rock based on the frequency of the vibration component due to the torque fluctuation appearing in the current waveform of the motor M and the average value of the absolute value of the current flowing to the motor M. Specifically, as shown in FIG. 6, determination unit 3 sets the reference frequency to the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of motor M, and determines the average value of the absolute values of the current. Then, a reference average value is set, and the property of the rock is determined based on the comparison result of the frequency and the reference frequency, the average value of the absolute value of the current and the reference average value. More specifically, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is higher than the reference frequency and the average value of the absolute values of the current is lower than the reference average value, the determination unit 3 Determined to be composed of hard rock containing large cracks. In addition, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is higher than the reference frequency and the average value of the absolute values of the current is higher than the reference average, the determination unit 3 Determined to be composed of hard rock. Furthermore, when the determination unit 3 is lower than the frequency reference frequency of the vibration component due to torque fluctuation appearing in the current waveform of the motor M and the average value of the absolute values of the current is higher than the reference average value It is determined that the composition is made. Note that a reference frequency serving as a reference for determining the level of the frequency of the vibration component due to torque fluctuation appearing in the current waveform of the motor M and a reference average serving as a reference for determining the level of the average value of the absolute values of the current. The value may be determined, for example, based on the data obtained by excavating the rock with a real machine and the result of the rock hardness survey. The reference average value for determining the property of the rock based on the frequency of the vibration component due to torque fluctuation appearing in the current waveform of the motor M and the average value of the absolute value of the current flowing to the motor M is The reference average value may be set to a value different from the reference average value when determining the property of the rock based on the peak value of the current waveform and the average value of the absolute values of the current.

  In this example, it is determined whether the rock quality is hard rock or soft rock, and in the case of hard rock, whether the crack is large or small. The higher the frequency of the vibration component due to the torque fluctuation appearing in the current waveform of the motor M, the higher the hardness of the rock, and the lower the average absolute value of the current when the rock is hard rock, the larger the crack becomes. Further, the lower the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M, and the higher the average value of the current, the lower the hardness of the rock becomes. Therefore, the determination unit 3 may output the hardness of the rock and the magnitude of the crack numerically based on the average value of the frequency and the current in the determination of the property of the rock.

  In addition, although not shown in the drawings, comparing the current waveform in the case of excavating a hard rock with a large crack with the current waveform in the case of excavating a hard rock with a small crack, the absolute value of the current becomes larger as the crack becomes larger. The effective value of the current decreases as well as the average value of Therefore, if the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is high and the effective value of the current is low, the determination unit 3 determines that the rock is composed of hard rock containing a large crack You may Further, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is high and the effective value of the current is high, the determination unit 3 determines that the rock mass is composed of hard rock containing small cracks. You may That is, in the determination of the property of the rock, the determination unit 3 uses the frequency of the vibration component due to the torque fluctuation appearing in the current waveform of the motor M as a determination material to be used instead of the average value of the absolute value of the current flowing through the motor M. The effective value of the current may be used.

  In this case, specifically, determination unit 3 sets the reference frequency to the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of motor M, and sets the reference effective value to the effective value of the current. The nature of the rock may be determined based on the comparison result of the frequency and the reference frequency and the comparison result of the effective value of the current and the reference effective value. More specifically, as shown in FIG. 7, determination unit 3 determines that the frequency of the vibration component due to torque fluctuation appearing in the current waveform of motor M is higher than the reference frequency, and the effective value of the current is lower than the reference effective value. If so, determine that the bedrock is composed of hard rock containing large cracks. In addition, when the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M is higher than the reference frequency and the effective value of the current is higher than the reference effective value, the judging unit 3 It is determined that the composition is Furthermore, when the judgment unit 3 has a frequency reference frequency lower than the frequency reference frequency of the vibration component due to the torque fluctuation appearing in the current waveform of the motor M, and the effective value of the current is higher than the reference effective value, It is determined that there is. The reference effective value serving as a reference for determining the level of the effective value of the current may be determined based on, for example, data obtained by excavating the rock with a real machine and the result of the hardness survey of the rock. Further, the reference effective value for determining the property of the rock based on the frequency of the vibration component due to the torque fluctuation appearing in the waveform of the current of the motor M and the effective value of the current flowing to the motor M is the waveform of the current of the motor M The reference effective value may be set to a value different from the reference effective value when determining the property of the rock based on the peak value of the current and the effective value of the current.

  In this example, it is determined whether the rock quality is hard rock or soft rock, and in the case of hard rock, whether the crack is large or small. The higher the frequency of the vibration component due to the torque fluctuation appearing in the current waveform of the motor M, the higher the hardness of the rock, and the lower the effective value of the current when the rock is hard rock, the larger the crack becomes. Further, the lower the frequency of the vibration component due to the torque fluctuation appearing in the current waveform of the motor M and the higher the effective value of the current, the lower the hardness of the rock becomes. Therefore, the determination unit 3 may output the hardness of the rock and the size of the crack numerically based on the frequency and the effective value of the current in the determination of the property of the rock.

  As mentioned above, the rock quality determination apparatus 1 of the present invention is detected by the current sensor 2 for detecting the current flowing to the motor M for driving the cutter head C provided at the tip of the boom B of the free cross section drilling machine E And a determination unit 3 that determines the nature of the rock in the face where the cutter head C excavates based on the current. In the rock quality determination apparatus 1 configured as described above, since the property of the rock in the face can be determined from the current flowing to the motor M, even if the property of the rock changes during excavation, the property of the rock can be grasped in a timely manner. It can quickly detect the presence of danger such as collapse. Further, since the property of the rock can be determined only by detecting the current of the motor M, it is not necessary to install a plurality of sensors, and the property of the rock can be grasped easily and inexpensively. Originally, when the motor M is provided with a current sensor, this current sensor may be used as the current sensor 2 in the rock quality determination device 1.

  When the determination unit 3 determines the property of the rock based on the peak value of the current waveform of the motor M and the average value of the current, the hardness of the rock can be determined. In addition, specifically, when the crest value in the waveform of the current of the motor M is higher than the reference crest value and the average value of the current is lower than the reference average value, the determination unit 3 is made of hard rock If it is determined that the wave height value of the current waveform of the motor M is lower than the reference wave height value and the average value of the current is higher than the reference average value, it may be determined that the rock is composed of soft rock.

  Furthermore, the determination unit 3 may determine the property of the rock based on the frequency of the vibration component caused by the torque fluctuation of the waveform of the current of the motor M and the average value of the current of the motor M, in this case In addition to the hardness of the rock, it is also possible to judge the size of the cracks contained in the rock. In addition, specifically, when the frequency of the vibration component of the current waveform caused by the torque fluctuation of the motor M is higher than the reference frequency and the average value of the current is lower than the reference average value, the determination unit 3 If the frequency is higher than the reference frequency and the average value is higher than the reference average, it is determined that the rock is a hard rock having a small crack, and the frequency is higher than the reference frequency. If the average value is lower than the reference average value, it may be determined that the rock is soft rock.

  While the preferred embodiments of the present invention have been described above in detail, modifications, variations and changes are possible without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... rock quality determination apparatus, 2 ... current sensor, 3 ... determination part, B ... boom, C ... cutter head, E ... free cross section excavating machine, M ... motor

Claims (4)

A current sensor for detecting an electric current flowing to a motor for driving a cutter head provided at a tip of a boom of the free cross section drilling machine;
Based on the crest value which is the amplitude of the waveform of the current detected by the current sensor and the average value of the absolute value of the current or the effective value of the current, the property of the rock in the face where the cutter head excavates is determined A rock quality determination apparatus comprising: a determination unit; A current sensor for detecting an electric current flowing to a motor for driving a cutter head provided at a tip of a boom of the free cross section drilling machine;
In the face where the cutter head excavates based on the frequency of the vibration component due to the torque fluctuation of the motor detected by the current sensor and the average value of the absolute value of the current or the effective value of the current A rock quality determination apparatus comprising: a determination unit that determines a property of a rock. The determination unit is
When the peak value of the current is higher than the reference peak value and the average value of the absolute values of the current is lower than the reference average value or the effective value of the current is lower than the reference effective value, the rock is composed of hard rock It is determined that
If the crest value of the current is lower than the reference crest value and the average value of the absolute values of the current is higher than the reference average value or the effective value of the current is higher than the reference effective value, the rock mass is composed of soft rock The rock quality determination apparatus according to claim 1, wherein the rock quality determination apparatus is determined. The determination unit is
If the frequency is higher than a reference frequency and the average value is lower than the reference average value or the effective value is lower than the reference effective value, it is determined that the rock is a hard rock having a large crack;
If the frequency is higher than the reference frequency and the average value is higher than the reference average value or the effective value is higher than the reference effective value, it is determined that the rock is a hard rock having a small crack;
When the frequency is lower than the reference frequency and the average value is higher than the reference average value or the effective value is higher than the reference effective value, it is determined that the rock is soft rock. The rock quality determination device according to Item 2.

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