Filler injection system for rock bolt hole, and filler injection method

Abstract

To provide a method of injecting a filler into a rock bolt hole formed in the ground capable of filling the rock bolt hole with the filler of the required amount.SOLUTION: After inserting an injection tube 19 extending from an injection pump 10 into a rock bolt hole 5, a filler 6 from the injection pump 10 is injected into the rock bolt hole 5. The discharge flow rate q of filler 6 is measured using a flow meter 20. When the cumulative injection amount Q based on the flow rate measured by the flow meter 20 has reached the pre-filling injection amount Q1 where the required filling amount Q0 of the rock bolt hole 5 is subtracted by the inertial discharge forecast amount Q2 of the filler 6 during the inertial discharge time after the injection pump 10 is stopped, an indication light 40 and / or a buzzer 45 are used to instruct the injection pump 10 to stop.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a rock bolt construction method in which a rock bolt is inserted into a rock bolt hole formed in a natural ground such as around a tunnel or a slope surface, and particularly relates to a system and an injection method for injecting a filling material into the rock bolt hole before or after the insertion.

Background Art

[0002] For example, in the construction of a mountain tunnel, in order to stabilize the excavated natural ground, a rock bolt construction method is performed in which a rock bolt is inserted from the tunnel excavation surface into the natural ground. The rock bolt construction method includes a step of forming a rock bolt hole in the natural ground and injecting a filling material such as mortar into the rock bolt hole (see Patent Document 1, etc.).

[0003] In the injection step, after inserting the tip of an injection pipe extending from an injection pump to the inner end of the rock bolt hole, a filling material such as mortar is pumped by the injection pump. As a result, the filling material is discharged from the tip of the injection pipe and injected into the rock bolt hole. While injecting, the injection pipe is gradually pulled toward the operator side. When the filling material overflows from the near-side opening that opens to the tunnel excavation surface in the rock bolt hole, it is determined that the rock bolt hole is filled with the filling material, and the injection pump is stopped. After that, a rock bolt is inserted into the rock bolt hole. After inserting a rock bolt into the rock bolt hole, there may be a case where the gap between the inner circumference of the rock bolt hole and the rock bolt is filled with a filling material.

[0004] Patent Document 1 describes that by providing a flow meter in an injection pump and obtaining the filling amount of the filling material, it is useful for judging the presence or absence of construction defects and the state of the surrounding natural ground.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] If a flowmeter is provided in the injection pump as in Patent Document 1, it is considered that a system for determining whether filling is completed can be constructed from the measured value. On the other hand, according to the inventor's findings, when a certain amount of filling material was discharged from the injection pump, the integrated measured flow rate by the flowmeter was less than the certain amount. In view of such findings, an object of the present invention is to fill a required amount of filling material into a rock bolt hole formed in the natural ground in the process of injecting the filling material into the rock bolt hole.

Means for Solving the Problems

[0007] In order to solve the above problems, the inventor conducted intensive research. As a factor causing a deviation between the actual discharge amount by the injection pump and the integrated measured flow rate by the flowmeter, it can be cited that the filling material extruded from the injection pump into the injection pipe has inertia. Since this type of filling material has a relatively large mass, it also has a large inertia, and even after the power supply to the injection pump is stopped, it continues to flow through the injection pipe for a while and is discharged from the tip of the injection pipe. It is considered that this inertial discharge amount after the power supply stop causes a deviation from the integrated measured flow rate. In view of such circumstances, the system of the present invention is a filling material injection system for injecting a filling material into a rock bolt hole formed in the natural ground, an injection pump for discharging the filling material, an injection pipe extending from the injection pump and inserted into the rock bolt hole, a flowmeter for measuring the discharge flow rate of the filling material, a determination unit that determines whether the injection amount of the filling material into the rock bolt hole based on the measured flow rate by the flowmeter has reached a pre-injection amount obtained by subtracting the predicted inertial discharge amount of the filling material during the inertial discharge time after the stop of the injection pump from the required filling amount of the rock bolt hole, a stop instruction unit that gives an instruction to stop the injection pump according to the determination, and is characterized by comprising the above.

[0008] Preferably, the filler injection system includes a flow meter for measuring the flow rate of the discharged filler, and a calculation unit for calculating the predicted inertial discharge amount based on the measured flow rate by the flow meter. It further includes the above.

[0009] Preferably, the stop instruction unit includes a reporting unit for the stop. Examples of the reporting unit include an indicator light, a buzzer, a monitor, etc.

[0010] Preferably, the stop instruction unit includes an output unit for outputting a command signal for automatically stopping the injection pump.

[0011] The method of the present invention is a filler injection method for injecting a filler into a rock bolt hole formed in the natural ground by an injection pump, including a step of inserting an injection pipe extending from the injection pump into the rock bolt hole to perform the injection, a step of measuring the discharge flow rate of the filler with a flow meter, and a step of instructing to stop the injection pump when the injection amount of the filler into the rock bolt hole based on the measured flow rate by the flow meter reaches the pre-injection amount obtained by subtracting the predicted inertial discharge amount of the filler during the inertial discharge time after the stop of the injection pump from the required filling amount of the rock bolt hole. It is characterized by comprising the above.

[0012] Preferably, the filler injection method includes a step of measuring the discharge flow velocity of the filler with a flow meter, and a step of calculating the predicted inertial discharge amount based on the measured flow velocity by the flow meter. It further includes the above. The predicted inertial discharge amount may be set according to the length of the injection pipe. The predicted inertial discharge amount may be set according to the height difference between the injection pump and the rock bolt hole.

Effect of the Invention

[0013] According to the present invention, in the step of injecting a filler into a rock bolt hole formed in the natural ground, a required amount of the filler can be injected into the rock bolt hole.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a mountain tunnel 1 under construction. In the mountain tunnel 1, a rock bolt 3 is driven from a tunnel excavation face 1a sprayed with shotcrete (not shown) into the natural ground 2.

[0016] In the rock bolt work, a rock bolt hole 5 is drilled in the natural ground 2 by a drill jumbo 4. Mortar 6 (filler) is injected into the formed rock bolt hole 5 by a filler injection system 9, and then the rock bolt 3 is inserted.

[0017] As shown in FIG. 1, a transport vehicle 8 such as a 4t truck has entered the mountain tunnel 1 under construction. The transport vehicle 8 is parked near the drill jumbo 4. A filler injection system 9 is loaded on the loading platform of the transport vehicle 8. The filler injection system 9 includes an injection pump 10, an injection pipe 19, a flow meter 20, a flow velocity meter 21, a control panel 30, and transmitting units 40 and 45.

[0018] As shown in Fig. 2, the injection pump 10 is composed of a general concrete placing pump and includes a pump section 11, a mixer 12, and an on-off switch 13. A hopper 14 (solid raw material input section) is provided above the mixer 12. A water supply passage 15 (liquid raw material input section) is connected to the mixer 12.

[0019] A cylindrical pump section 11 extends from the mixer 12. A screw 11a is provided inside the pump section 11.

[0020] The on-off switch 13 is used to operate the start and stop of the injection pump 10. By operating the injection pump 10, the cement 6a (solid raw material) input into the hopper 14 and the water 6w (liquid raw material) from the water supply passage 15 are kneaded in the mixer 12 to form the mortar 6 (filler). The mortar 6 is pushed out from the pump section 11 to the injection pipe 19 by the rotation of the screw 11a.

[0021] As shown in Fig. 1, the injection pipe 19 extends from the discharge port 11p of the pump section 11 to the elevated work platform 4d of the drill jumbo 4 and is inserted into the rock bolt hole 5 to be injected from there.

[0022] As shown in Fig. 2, a flow meter 20 and a flow velocity meter 21 are interposed between the discharge port 11p and the injection pipe 19 or in the middle of the injection pipe 19. The flow meter 20 measures the discharge flow rate q (instantaneous flow rate) of the mortar 6 from the injection pump 10. Preferably, the flow meter 20 is an electromagnetic flow meter that detects the electromotive force (voltage) generated by the electromagnetic induction action of the flow of the fluid (conductor) and the magnetic field. More preferably, the flow meter 20 is a digital flow meter that outputs the detected voltage, that is, the measured value of the mortar flow rate, as a digital signal.

[0023] The flow velocity meter 21 measures the flow velocity v of the mortar 6 discharged from the injection pump 10. Preferably, the flow velocity meter 21 is a digital flow velocity meter that outputs the measured flow velocity value as a digital signal. Note that the flowmeter 20 may also serve as a flow velocity meter, and the flow velocity may be calculated by dividing the flow rate by the cross-sectional area of the flow path. The flow velocity meter 21 may also serve as a flowmeter, and the flow rate may be calculated by multiplying the flow velocity by the cross-sectional area of the flow path.

[0024] As shown in FIG. 2, the control panel 30 includes a processing unit 31 (determination unit, calculation unit), a signal conversion unit 32, and a setting unit 33. Preferably, the outer casing 34 of the control panel 30 has a waterproof and dustproof specification. The processing unit 31 includes a CPU 31a and a storage unit 31m, and performs a control operation of the filler injection system 9. In the storage unit 31m, a control program and arithmetic expressions for operating the filler injection system 9 are stored. Examples of the arithmetic expressions include an arithmetic expression for calculating the inertial discharge prediction amount Q2, which will be described later. The processing unit 31 may be configured by a personal computer (hereinafter referred to as "PC") or may be configured by a programmable logic controller (hereinafter referred to as "PLC").

[0025] The processing unit 31 and the signal conversion unit 32 are wired-connected by an Ethernet cable 35 or the like. Note that the processing unit 31 may include the signal conversion unit 32.

[0026] The signal conversion unit 32 is configured by, for example, an Ethernet switch. Through the signal conversion unit 32, the processing unit 31 and various input / output devices are connected so as to be able to transmit signals. Input devices connected to the signal conversion unit 32 and thus to the processing unit 31 include the on-off switch 13, the flowmeter 20, the flow velocity meter 21, the setting unit 33, and the like. Output devices connected to the signal conversion unit 32 and thus to the processing unit 31 include the indicator lamp 40 and the buzzer 45, and the like.

[0027] The setting unit 33 receives input of various setting values. Examples of the setting values include the required filling amount Q0 of the mortar 6 (filler) into each rock bolt hole 5. The required filling amount Q0 is the volume of the mortar 6 required to fill the rock bolt hole 5 to full capacity, and is derived based on, for example, the volume of the rock bolt hole 5, that is, the product of the diameter of the drilling bit and the drilling depth. The required filling amount Q0 may be set in consideration of the cross-sectional area of the rock bolt 3.

[0028] Preferably, the setting unit 33 is a digital device that receives a set value numerically (digitally) and outputs it to the signal conversion unit 32 as a digital signal. The set value such as the required filling amount Q0 by the setting unit 33 is input to the processing unit 31 via the signal conversion unit 32. The processing unit 31 (determination unit) determines whether the amount of mortar injected into the rock bolt hole 5 has reached the amount corresponding to the injection pump stop timing (the pre-filling injection amount Q1 described later) based on the measured flow rate q by the flow meter 20 and the required filling amount Q0 by the setting unit 33, etc.

[0029] As shown in FIG. 2, the indicator lamp 40 (alarm unit by light) is preferably arranged at a place with a good view of the mortar injection site in the tunnel 1. For example, the indicator lamps 40 are respectively provided at the upper ends of the columns 44 erected on the transport vehicle 8.

[0030] The indicator lamp 40 includes, for example, three (a plurality of) light emitting parts 41, 42, 43 arranged vertically. These light emitting parts 41 to 43 have different light emitting colors from each other. For example, the upper light emitting part 41 emits red light, the middle light emitting part 42 emits yellow light, and the lower light emitting part 43 emits blue or green light respectively, but the present invention is not limited to this. Preferably, the indicator lamp 40 is a rotating indicator lamp in which the light emitting parts 41 to 43 are rotated.

[0031] The indicator lamp 40 is controlled to blink by the control panel 30. The degree of mortar injection into each rock bolt hole 5 is notified by the number of the lit light emitting parts 41 to 43 in the indicator lamp 40. As the number of the lit light emitting parts 41 to 43 increases, it indicates that the injection degree is large. The lighting of all the light emitting parts 41, 42, 43 represents an instruction to stop the injection pump 10.

[0032] Also, the buzzer 45 (alarm unit by sound) is controlled by the control panel 30. The alarm sound from the buzzer 45 represents an instruction to stop the injection pump 10. The indicator lamp 40 and the buzzer 45 constitute a stop instruction unit that gives an instruction to stop the injection pump 10 according to the determination by the processing unit 31 (determination unit).

[0033] In the rock bolt work, the mortar (filler) is filled into the rock bolt hole 5 by operating the filler injection system 9 as follows. <Required filling amount setting step> In advance, the required filling amount Q0 of the mortar 6 (filler) in the rock bolt hole 5 to be injected is set by the setting unit 33. The set required filling amount Q0 is sent to the processing unit 31 and stored in the storage unit 31m. By inputting values such as the length and inner diameter of the rock bolt hole 5, which are the calculation factors of the required filling amount Q0, into the setting unit 33, the input data may be sent to the processing unit 31 via the signal conversion unit 32 so that the required filling amount Q0 is calculated in the processing unit 31. Preferably, the required filling amount setting step is executed each time the length or cross-sectional area of the rock bolt hole 5 to be injected is changed.

[0034] <Injection pipe insertion step> As shown in FIG. 1, the operator B in charge of the injection pipe operation rides on the elevated work platform 4d of the drill jumbo 4, for example, and inserts the injection pipe 19 into the rock bolt hole 5 from the hand-side opening 5a of the rock bolt hole 5 to be injected and into the inside of the rock bolt hole 5. When the tip of the injection pipe 19 is inserted to the far end of the rock bolt hole 5, a signal is given.

[0035] <Injection pump operation start step> The operator A in charge of the injection pump operation performs an operation to start the operation by the on / off switch 13 of the injection pump 10 in response to the signal.

[0036] <Injection step> By the operation of the injection pump 10, the mortar 6 is pumped from the injection pump 10 into the injection pipe 19, discharged from the tip of the injection pipe 19, and injected into the rock bolt hole 5. The operator B gradually pulls the injection pipe 19 toward the hand side while injecting. As a result, the mortar 6 is filled from the far end inside the rock bolt hole 5 toward the hand side.

[0037] <Flow measurement step> In the injection process, the flow rate q (L / min) of the mortar 6 is measured by the flow meter 20. The measured mortar flow rate is input to the processing unit 31 via the signal conversion unit 32. The processing unit 31 calculates the current measured injection volume Q (L) of the mortar 6 in the rock bolt hole 5 during injection by integrating the input measured flow rate.

[0038] <Injection degree calculation step> Furthermore, the processing unit 31 reads the set value of the required filling volume Q0 from the storage unit 31m and calculates the ratio R between the measured injection volume Q and the required filling volume Q0 according to the following formula. R = Q / Q0 (1) The ratio R indicates the mortar injection degree with respect to the required filling volume Q0 in the rock bolt hole 5 during injection.

[0039] The processing unit 31 adjusts the number of the light emitting parts 41 to 43 to be lit among the indicator lights 40 according to the calculated injection degree R. The operator B in charge of the injection pipe operation can accurately grasp in real time the injection degree of the mortar 6 in the rock bolt hole 5 during the injection operation by looking at the lighting status of the indicator light 40. According to the lighting status, the pulling degree of the injection pipe 19 to the operator's side is adjusted. Thereby, the operator B can pull the injection pipe 19 to the operator's side at an appropriate speed without relying on intuition.

[0040] <Inertial discharge prediction amount calculation step> In parallel with the flow rate measurement by the flow meter 20, the discharge flow velocity v (m / min) of the mortar 6 is measured by the flow velocity meter 21. The measured flow velocity v is input to the processing unit 31 via the signal conversion unit 32. The processing unit 31 (calculation unit) calculates the inertial discharge prediction amount Q2 based on the measured flow velocity v.

[0041] Specifically, the inertial discharge prediction amount Q2 is the amount (L) of the mortar 6 that is predicted to be discharged by inertia even after the injection pump 10 is stopped. Since the inertial force of the mortar 6 discharged from the injection pump 10 depends on the velocity v of the mortar 6, the inertial discharge prediction amount Q2 is represented by a functional formula (2) with the velocity v as a variable. Q2 = f(v) (2) Equation (2) may be a linear function of the velocity v or a quadratic function of the velocity v. The CPU 31a reads the function equation (2) from the storage unit 31m, applies the measured value of the flow velocity v to the function equation (2) for calculation, and obtains the inertial discharge prediction amount Q2. The inertial discharge prediction amount Q2 is, for example, about several percent to several tens of percent of the required filling amount Q0.

[0042] <Example 1 of Variation in Calculation of Inertial Discharge Prediction Amount> The inertial discharge prediction amount Q2 may be set according to the length L19 of the injection pipe 19. The larger the injection pipe length L19, the greater the flow resistance and the smaller the inertial discharge prediction amount Q2. The injection pipe length L19 is input in advance by the setting unit 33. The value of the input injection pipe length L19 is stored in the storage unit 31m. During the inertial discharge prediction amount calculation process, the CPU 31a reads the value of the injection pipe length L19 from the storage unit 31m and calculates the inertial discharge prediction amount Q2. The inertial discharge prediction amount Q2 may be calculated from the velocity v and the injection pipe length L19. The function equation (2) may include the velocity v and the injection pipe length L19 as variables.

[0043] <Example 2 of Variation in Calculation of Inertial Discharge Prediction Amount> The inertial discharge prediction amount Q2 may be set according to the height difference ΔH between the injection pump 10 and the lock bolt hole 5. When the lock bolt hole 5 is at a higher position than the injection pump 10, the greater the height difference ΔH, the smaller the inertial discharge prediction amount Q2. The height difference ΔH is input in advance by the setting unit 33. Strictly speaking, the height difference ΔH from the discharge port 11p of the injection pump 10 to the hand side opening 5a of the lock bolt hole 5 is input. The value of the input height difference ΔH is stored in the storage unit 31m. During the inertial discharge prediction amount calculation process, the CPU 31a reads the value of the height difference ΔH from the storage unit 31m and calculates the inertial discharge prediction amount Q2.

[0044] The inertial discharge predicted amount Q2 may be calculated from the velocity v or the injection pipe length L19 and the height difference ΔH. The function formula (2) may include the velocity v or the injection pipe length L19 and the height difference ΔH as variables. The inertial discharge predicted amount Q2 may be calculated from the velocity v, the injection pipe length L19, and the height difference ΔH. The function formula (2) may include the velocity v, the injection pipe length L19, and the height difference ΔH as variables. The inertial discharge predicted amount calculation step may be performed from the start or the initial stage of the injection step, or may be executed from the stage where the injection has progressed to a certain extent (for example, about 1 / 2 to 2 / 3 of the required filling amount Q0).

[0045] <Injection pump stop timing determination step> Furthermore, the processing unit 41 (determination unit) obtains the pre-filling injection amount Q1 by subtracting the inertial discharge predicted amount Q2 from the required filling amount Q0. Q1 = Q0 - Q2 (3) Then, it is determined whether or not the measured injection amount Q has reached the pre-filling injection amount Q1.

[0046] <Reporting step (injection pump stop instruction step)> When it is determined that the measured injection amount Q has reached the pre-filling injection amount Q1 (Q ≥ Q1), the processing unit 31 outputs an all-on instruction to the indicator lamp 40 via the signal conversion unit 32. As a result, all of the three light emitting units 41, 42, and 43 are lit. That is, a report instructing the stop of the injection pump 10 by light emission from the indicator lamp 40 is made. In addition, an alarm sound instructing the stop of the injection pump 10 is reported from the buzzer 45.

[0047] <Injection pump stop step> In response to this, the operator A performs an operation to stop the operation by the on-off switch 13 of the injection pump 10. As a result, the supply of driving power to the injection pump 10 is stopped, and the operation of the injection pump 10 is stopped.

[0048] <Modification example of injection pump stop step> Instead of manual stop by Operator A, the processing unit 31 (output unit) may output an automatic stop command signal to the injection pump 10 via the signal conversion unit 32, and the injection pump 10 may be automatically stopped according to the command signal.

[0049] <Inertial discharge process> During the inertial discharge time after the stop of the injection pump 10, the mortar 6 continues to be discharged from the tip of the injection pipe 19 due to inertia. Even after the stop of the injection pump 10, Operator B holds the tip of the injection pipe 19 inserted into the anchor bolt hole 5 during the inertial discharge time. Thereby, the mortar 6 discharged by inertia is injected into the anchor bolt hole 5. Therefore, it is possible to prevent the mortar 6 for inertial discharge from being wasted and discharged outside the anchor bolt hole 5. The inertial discharge time is, for example, about several seconds to several tens of seconds, preferably about 2 seconds to 5 seconds.

[0050] The actual discharge amount Q3 of the mortar 6 due to inertia after the injection pump stops approximates the inertial discharge predicted amount Q2 obtained by Equation (2). Q3≒Q2 (4) The total actual discharge amount Qt after the inertial discharge time elapses is a value obtained by adding the inertial actual discharge amount Q3 to the pre-filling injection amount Q1. Qt = Q1 + Q3 (5) Therefore, from Equations (3) to (5), the total actual discharge amount Qt approximates the required filling amount Q0. Qt≒Q0 (6) In this way, the anchor bolt hole 5 can be filled with the required amount of mortar 6.

[0051] <Flow measurement continuation process> Even after the stop of the injection pump 10 (stop of power supply), the power supply to the flow meter 20 continues at least until the inertial discharge time elapses. Then, the measurement of the mortar flow rate by the flow meter 20 continues until the inertial discharge time elapses. Thereby, the deviation between the final integrated injection amount Qe and the total actual discharge amount Qt after the inertial discharge time elapses by the measurement of the flow meter 20 can be reduced.

[0052] The processing unit 31 stores the final integrated injection amount Qe (≒ Qt) as the total injection amount into the rock bolt hole 5 in the storage unit 31m and resets the integrated injection amount. The data such as the stored injection amount is used for creating documents such as work reports.

[0053] The operator B pulls out the injection pipe 19 from the hand-side opening 5a of the rock bolt hole 5 filled with mortar. Subsequently, the rock bolt 3 is driven into the rock bolt hole 5 filled with mortar by operating the drill jumbo 4. In this way, the mortar 6 is filled in each drilled rock bolt hole 5 and then the rock bolt 3 is driven in.

[0054] The present invention is not limited to the above-described embodiment and can be variously modified. For example, the present invention is applicable not only to tunnel construction but also to slope work and the like as long as it is a method for injecting a filler into a rock bolt hole formed in a natural ground. That is, when driving a rock bolt into a slope, the present invention can also be applied to the step of injecting a filler into the rock bolt hole of the slope. The warning unit may be composed of only one of the indicator lamp 40 and the buzzer 45, and the other may be omitted. The warning unit may include a monitor that displays the injection degree and thus reports the injection stop timing. The filler injection system according to the present invention is applicable not only to the pre-injection method in which mortar is injected into the rock bolt hole 5 and then the rock bolt 3 is inserted, but also to the post-injection method in which the rock bolt 3 is inserted into the rock bolt hole 5 and then mortar injection is performed. The filler is not limited to mortar and may be a foamed resin such as a urethane-based resin.

Industrial Applicability

[0055] The present invention is applicable to, for example, rock bolt work in mountain tunnels.

Explanation of Signs

[0056] 1 Mountain tunnel 2 Rock mass 3 Rock bolt 5 Rock bolt hole 5a Hand-side opening 6 Mortar (filler) 9 Filler injection system 10 Injection pump 13 On-off switch 19 Injection pipe 20 Flow meter 21 Flow velocity meter 30 Control panel 31 Processing unit (judgment unit, calculation unit, output unit) 33 Setting unit 40 Indicator light (alarm unit) 41, 42, 43 Light emitting part 45 Buzzer (alarm unit)

Claims

1. A system for injecting a filler into a rock bolt hole formed in a natural ground, comprising: An injection pump that discharges the filler; an injection pipe extending from the injection pump and inserted into the rock bolt hole; A flow meter that measures the discharge flow rate of the filler; a determination unit that determines whether an injection amount of the filler into the rock bolt hole based on a flow rate measured by the flow meter has reached a pre-filling injection amount obtained by subtracting a predicted inertial discharge amount of the filler during an inertial discharge time after the injection pump is stopped from a required filling amount of the rock bolt hole; a stop instruction unit that instructs the injection pump to stop in response to the determination; A filler injection system comprising:

2. A flow meter that measures the flow velocity of the discharged filler; A calculation unit that calculates the inertial discharge predicted amount based on the flow velocity measured by the flow meter; The filler injection system of claim 1 further comprising:

3. The filler injection system according to claim 1 or 2, wherein the stop instruction unit includes an alarm unit for issuing an alarm for the stop.

4. 3. The filler injection system according to claim 1, wherein the stop instruction unit includes an output unit for outputting a command signal for automatically stopping the injection pump.

5. A method for injecting a filler into a rock bolt hole formed in natural ground by an injection pump, comprising: a step of inserting an injection pipe extending from the injection pump into the rock bolt hole to perform the injection; Measuring the discharge flow rate of the filler with a flow meter; a step of issuing an instruction to stop the injection pump when the injection amount of the filler into the rock bolt hole based on the flow rate measured by the flow meter reaches a pre-filling injection amount obtained by subtracting a predicted inertial discharge amount of the filler during an inertial discharge time after the injection pump is stopped from a required filling amount of the rock bolt hole; A filler injection method comprising:

6. Measuring the discharge flow rate of the filler with a flow rate meter; calculating the predicted inertial discharge amount based on the flow velocity measured by the flow meter; The method of claim 5 further comprising:

7. The method for injecting a filler material according to claim 5 , wherein the predicted inertial discharge amount is set according to the length of the injection tube.

8. The filler injection method according to claim 5 , wherein the predicted inertial discharge amount is set according to a height difference between the injection pump and the rock bolt hole.

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