JPH10114938A - Execution method and device of grouting in rock bed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase injection efficiency, by adding a pulsatory pressure with a specified frequency as a weight load to the injection pressure when a grout is injected in cracked rocks. SOLUTION: A grouting device S for rock beds is constituted of a pressure pipe line 1, a pressurizing feeder 2 of a grout, a pulsatory pressure generator 3, and an injection part 4 into rocks. The grout mixed in a grout storage tank 10 is pressurized by an injection pump 11 and fed to the pipe lines 1, in the pressurizing feeder 2. The grout fed from the pressurizing feeder 2 is sucked by a pulsatory pressure-generating pump 28 in the pulsatory pressure generator 3 and discharged thereby to send the grout with pressure into the injection part 4 while adding a pulsatory pressure with 30Hz or lower frequency, preferably about 10Hz frequency, to a steady pressure as a base, and the grout that a pulsatory pressure with a specified frequency is added to a specified injection pressure is injected into a rock bed R from a packer 21 in the injection part 4. In this way, the fluidizing resistance of the grout having a high concentration and viscosity is greatly reduced and the grout can be rapidly penetrated into fine cracks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grouting method and a grouting method for a ground including a rock mass, in particular, a so-called cracked rock mass including a large number of fine cracks. Further, the present invention does not exclude a ground or a concrete structure in which the waterproofness / stability needs to be significantly increased.

[0002]

2. Description of the Related Art In recent years, a storage system utilizing a deep underground rock cavity, such as a geological disposal of high-level radioactive waste and an underground storage of petroleum and LPG, has been receiving attention. It is an important issue to secure the sealing and stability of the rock cavity, and to control the advection of groundwater and strengthen the rock in the loose area of so-called cracked rock containing many microcracks. There is an urgent need to improve the performance of grouting technology for porous rock. In ordinary rock grouting work, ordinary cement is mainly used as the grout material, and the water-to-cement ratio (W / C) is gradually increased from 10 to 1 as a compound while gradually increasing the ratio under the prescribed injection pressure. It is common to inject steadily until the flow stops or a defined injection volume is reached. However, filling status packing density is low to crack under normal construction methods also becomes also the heterogeneous, for further penetration injection into the following fine cracks 100~200μm is difficult, permeability after improvements ^10-5 cm
/ S (about 1 in Lugion value) is the limit. However, in order to construct a storage system for rock cavities, it is essential to improve the surrounding rock to a low water permeability of 10 ^-6 to 10 ^-7 cm / sec or less. Performance is significantly lacking.

In order to improve the performance of the rock grouting technique, a method of improving the permeability by atomizing the material itself such as colloidal cement or ultrafine cement is mainly used. New construction methods have also been tried. This construction method was proposed in 1987 as a part of the research results of the Striper Project led by the OECD and Nuclear Energy Commission aiming at the geological disposal of high-level radioactive waste. This is a method of injecting a high-concentration, high-viscosity grout material while giving components. If the usual injection method is a static injection method, this construction method can be called a dynamic injection method. In this project, we conducted a special viscosity test in which the cup of the outer cylinder of a double-cylindrical rotational viscometer was vibrated vertically, examined the rheological properties of high-concentration, high-viscosity grout materials, and increased the frequency As a result, it was found that the apparent viscosity of the grout material decreased and the flow characteristics of the grout material approached Newtonian flow. More specifically, in a vibration state in which the frequency is 300 Hz or less, as the frequency and the shear strain amplitude (displacement amplitude due to vibration / gap width between the inner and outer cylinders) increase, the apparent viscosity of the grout material, that is, It concludes that flow resistance is reduced. The dynamic injection method was proposed by analogy with this finding, and the method used is different from that used in the viscosity test. However, by adding a dynamic pressure component to the injection pressure, the flow resistance of the grout material is increased as in the viscosity test. Was developed on the premise that it would decrease and thus improve permeability. Specifically, a dynamic pressurizing device P shown in FIG. 14 has been developed. That is, the piston 100 in the steel cylinder 102 is driven by the percussion drill 100 driven by the compressed air G.
The hammering is performed to continuously apply an impact pressure to the grout material stored in the cylinder 102. Furthermore,
In the figure, 104 is a slurry container, 106 is a detector,
108 is a valve. This grout material is a pressure-resistant hose 11
Packer 1 is inserted into injection hole H formed in rock R through
The injection is carried out while keeping hermetically sealed by 12. According to the above-mentioned conclusion in the viscosity test, the effect of the vibration is maximized at around 300 Hz. However, in the realized dynamic pressurizing device, the frequency is limited to 40 Hz and fixed due to the relation of the vibration input power. doing.

[0004] However, comparing the vibration viscosity test in the stripper project with the injection mechanism using a dynamic pressurizer, the following physical differences are observed, and the dynamic effect similar to the viscosity test is obtained. It is unknown whether it can be obtained in actual injections. That is, in the vibration viscosity test, the entire measurement sample periodically undergoes speed fluctuation due to sinusoidal vertical vibration of the outer cylinder. On the other hand, in the pressurization method using a percussion drill, an impulsive stress wave (pressure wave) rises on the piston surface every hammering, and these propagate sequentially through the grout material at the sound speed of the material.
Only the instantaneous pressure change is applied only to the portion where the stress wave is passing, and the entire grout is not subject to periodic speed fluctuation. In the vibration viscosity test, vibration is applied in a direction (perpendicular direction) perpendicular to the rotational flow direction of the measurement sample, and a speed fluctuation occurs in this direction. On the other hand, in the pressurization method using a percussion drill, a stress wave propagates as a longitudinal wave in the same direction as the flow direction of the grout material at the time of injection. In the pressurization method using a percussion drill, the pressure change due to the passage of a shocking stress wave is instantaneous in the order of several milliseconds, and it is difficult to sufficiently excite the constituent particles of the grout material. Further, it is not mechanically easy to control the amplitude of the pressure change, and the attenuation of the wave with respect to the propagation distance is remarkable. Percussion drill type dynamic pressing device and artificial crack test specimen (crack width 100 μm, flow path width 50 mm, length 3 m)
Does not clearly demonstrate the effect of dynamic injection on static injection. In addition, the percussion drill type dynamic pressurizing device has a problem that the machine is large and generates large vibration and noise.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and further develops the basic technical idea of the prior art disclosed in the striper project.
Regardless of the percussion method, the flow resistance of the grout material is further improved to increase its permeability,
It is an object of the present invention to provide a method for constructing a rock grout capable of efficiently injecting a high-concentration and high-viscosity grout material into a fine rock crack having a diameter of not more than m and an apparatus for performing the method. For this reason, the present inventors have newly developed a double cylinder rotational viscometer, and a viscosity test in which the outer cylinder cup of the double cylinder rotational viscometer is vibrated in the same horizontal rotational direction as the flow direction of the measurement sample. Pulsating pressure generating pump and artificial crack specimen (crack width 50-200 μm, channel width 40 mm, length 2.9 m)
Various static and dynamic injection tests were carried out, and by paying attention to the characteristics obtained from these two tests, the frequency of the pulsating pressure was 5
The effect of dynamic injection was confirmed in the range of 30 Hz to 30 Hz, and it was found that the effect was maximized especially at around 10 Hz, and the present invention was made based on this finding. In these viscosity tests and injection tests, 5
Although the frequency range smaller than Hz has not been implemented, it is fully anticipated that the lower limit of the frequency of the pulsating pressure includes a frequency lower than 5 Hz based on the above findings. Further, in the pulsating pressure generating pump, it is possible to apply a periodic speed fluctuation to the entire grout material under a selected predetermined frequency, and to generate a stable pulsating pressure, the effect of the present dynamic injection. Is also an indispensable factor for achieving the above, and a pulsating pressure generation mechanism was developed based on this finding. That is, the present invention has achieved the object of the present invention by a method of generating a regular pulsating pressure by incorporating a servo control mechanism into a pulsating pressure generating mechanism and adding this to the injection pressure.

[0006]

The rock grouting method and the rocking grouting apparatus according to the present invention have the following construction. That is, the first method of constructing a rock grout of the present invention is to feed grout material at a predetermined injection pressure through a pressure feed piping line, and to feed the grout material with an injection pipe at the end into an injection hole drilled in the cracked rock. In the grouting for injecting the grout material, a pulsating pressure having a specific frequency selected from a frequency range of 30 Hz or less is superimposed on the injecting pressure. Here, the lower limit of the frequency range includes a frequency range of several seconds in a cycle.
The second method for constructing a rock grout according to the present invention is a method for grouting a cracked rock mass, in which grout material is pumped at a predetermined injection pressure and injected into the rock through an injection pipe at the end thereof. A pulsating pressure generating pump is interposed in the middle of the pressure feed pipe line inserted into the hole, and the pulsating pressure generating pump generates a pulsating pressure having a specific frequency specified and selected from a frequency range of 30 Hz or less. Pulsating pressure is superimposed on the pulsating pressure. The third method of constructing a rock grout according to the present invention is a method for grouting a cracked rock mass, which is performed in a pressure feeding pipe line from an injection pump for feeding a grout material at a predetermined pressure to an injection pipe inserted into an injection hole. In addition, a positive displacement pulsating pressure generating pump driven by a hydraulic servo actuator is installed, and a means for suppressing the propagation of pressure fluctuations to the upstream side is provided at an inlet pipe portion of the pulsating pressure generating pump. Using a servo control device composed of an oscillator that oscillates signal waveforms such as waves, triangular waves, and square waves and a servo controller, a pressure waveform detected by a pressure sensor attached near the mouth of the injection pipe and a command from the oscillator And performing feedback control on the operation of the hydraulic servo actuator so that both waveforms match. More, in the pulsation pressure generating pump, 30H
z has a specified frequency selected from the frequency range equal to or less than z, and generates a pulsating pressure approximate to the signal waveform, and the function of the pressure fluctuation propagation suppressing means from the pulsating pressure generating pump to the injection pipe. The pulsating pressure is added only to the pressure-feeding piping line, and the component of the pulsating pressure is superimposed on the pressure of the infusion pump to improve the permeability of the grout material,
It is characterized in that a grout material is injected into small cracks quickly and with high density. The rock grout construction apparatus of the present invention is used to carry out each of the above methods, and has the following configuration. In grouting for cracked rock, an apparatus used for a method of dynamically injecting grout material by adding a pulsating pressure component to an injecting pressure, and an injection pump for feeding out grout material at a predetermined pressure When,
An injection pipe inserted into the injection hole to allow the grout material to penetrate the cracks in the rock, and a volumetric pulsating pressure generated by a hydraulic servoactuator, installed in the middle of a pressure feed pipe line from the injection pump to the injection pipe. A pump, means attached to the inlet pipe of the pulsating pressure generating pump, for suppressing propagation of pressure fluctuations to the upstream side, and a pressure sensor attached near the mouth of the injection pipe to detect the injection pressure. Further, using a servo control device including an oscillator that oscillates signal waveforms such as a sine wave, a triangular wave, and a square wave, and a servo controller, a pressure waveform detected by the pressure sensor and a signal instructed by the oscillator. By performing feedback control on the operation of the hydraulic servo actuator so that both waveforms match by comparing with the waveform, 30 Hz or less A pulsating pressure generating pump having a specific frequency selected and instructed from a frequency range and approximated to a signal waveform is generated by the pulsating pressure generating pump, and the pulsating pressure is supplied from the pulsating pressure generating pump to the injection pipe by a pressure feeding pipe. And pulsating pressure control means added only to the line.

(Operation) The grout material is pulsated at a predetermined frequency in the flow direction in the pressure feed pipe line. As a result, the entire grout material undergoes speed fluctuation, and the constituent particles of the grout material are sufficiently excited. Then, the grout material that enters the rock from the injection pipe has a reduced flow resistance, improves permeability, and penetrates into fine rock cracks. In addition, the pulsating pressure acts on the rock to contribute to preventing clogging of the grout material. In the rock grouting equipment, a displacement type pulsating pressure generating pump driven by a hydraulic servo actuator is installed in the middle of the pressure feed piping line from the injection pump to the injection pipe, and an oscillator that oscillates a signal waveform such as a sine wave. The operation of the hydraulic servo actuator is automatically controlled by using a servo controller including a servo controller so that the pressure waveform detected at the mouth of the injection pipe matches the signal waveform. As a result, a stable pulsating pressure is generated by the pulsating pressure generating pump based on the signal waveform selected from the frequency range of 30 Hz or less, and this pulsating pressure is added to the pressure feeding piping line up to the injection pipe.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for rock grout according to the present invention will be described with reference to the drawings.
1 and 2 show embodiments of a rock grouting apparatus according to the present invention. That is, FIG. 1 shows a system configuration of a rock grouting apparatus of one embodiment, and FIG. 2 shows another embodiment as a means for suppressing propagation of pressure fluctuation. Furthermore,
FIGS. 3 to 8 verify the effect of the embodiment of the present invention. FIG. 3 shows an injection specimen having an artificial crack.
6 to 6 show the results of the dynamic injection test, and FIGS. 7 and 8 show the results of the wave analysis.

The optimum frequency of the vibration viscosity test (FIGS. 9 to 13)
Before the description of the grouting apparatus of the present embodiment, the rheological characteristics of the grout material under vibration and the frequency range where the vibration effect is most remarkable in these characteristics will be described. FIG. 9 and FIG. 10 show an outline of a vibration viscosity test apparatus T using a double cylindrical rotary viscometer. In this vibrating viscosity test apparatus T, a test body 52 having a double cylinder configuration of an inner cylinder 50 and an outer cylinder 51 is mainly used, and the sample is an inner cylinder 5.
It is sealed in the gap between the outer cylinder 51 and the outer cylinder 51. The inner cylinder 50 is connected to a rotational viscometer 54 via a torque meter 53. The rotational viscometer 54 is supported on an XY moving table 55. The outer cylinder 51 is linked to a micro (small) vibrator 57 via a bracket 56. In addition, 58 is a vibration sensor, 59 is a drive power supply, 60 is a charge amplifier, 61
Is an oscilloscope. The specifications of the device are (inner cylinder radius: 13 mm, outer cylinder radius: 15 mm, gap: 2 mm, inner cylinder height: 70 mm, inner cylinder rotation speed: 5 to 400 rpm, 6-speed shift), and a small shaker. (Excitation force: 50 N, maximum acceleration: 33 g, frequency: DC to 14 kHz), and vibrates the outer cylinder sinusoidally in the same circumferential direction as the rotational flow direction. In this test, a method of monotonously increasing the rotation speed of the inner cylinder is applied, and the frequency (frequency) f and the speed amplitude uθ are applied.
(The maximum speed of the inner wall of the outer cylinder) was controlled. Where f and uθ
Is constantly measured by a vibration sensor and a vibration meter. At the time of measurement,
The sample is given the same shearing history and a measurement time of one minute for each rotation speed to enhance the reproducibility of the measured values. As the test material (grout material), ultra-fine cement (abbreviated as SF), bentonite from Yamagata (abbreviated as BE1), and bentonite from Wyoming (abbreviated as BE2) were used, and the water content was (W
/SF=0.5, W / BE1 = 8, W / BE2 = 12)
It is. As a dispersant, naphthalene sulfonate was used for SF, and sodium hexametaphosphate was used for BE1 and BE2, and 2% was added uniformly in a weight ratio with respect to a solid content. A high-speed shearing stirrer was used to knead the materials, and samples were prepared under predetermined procedures and time management. After kneading, SF was immediately used, and BE1 and BE2 were stirred again after 24 hours and subjected to the test.

FIG. 11 shows the results of a vibration viscosity test (including a vibration-free vibration test) at a constant speed (uθ = 3 cm / s) in which the frequency is changed in the range of f = 0 to 40 Hz. Speed D
This shows the relationship with the shear stress τ, that is, the flow curve. As can be seen from the measurement results, the properties of the non-Newtonian fluid are remarkable in the high-viscosity grout material. In BE2, a clear slip is seen between the cylindrical wall and the sample. In the low shear velocity region, the influence of the vibration is large, and it can be seen that, particularly in BE1, D ≦ 42 s ⁻¹ approaches the Newtonian fluid (the gradient of the flow curve approaches 45 °). As a feature common to all the materials, it is noted that the effect of the vibration becomes strongest around f = 10 Hz. Here, as shown in FIG.
_{When a} (= τ / D) is expressed, the above-mentioned features can be understood more clearly. The vibration input power given to the sample is (power ∝
uθ ² f). Therefore, in the constant speed test, f
As the power increases, the power also increases proportionally. As a result, the fluidity of the grout material is most improved in the frequency range where the power is small, and the importance of the frequency in dynamic injection can be understood. FIG. 13 shows the results of a vibration viscosity test in which the vibration input power was controlled to be constant. In this test, f = 10 Hz, uθ
= 3 cm / s, f and uθ were changed so that the power became constant, and the result that the excitation effect was greatly exhibited in the low frequency range of 7 Hz and 10 Hz was obtained.

As described above, a special vibration viscosity test was performed using a double cylindrical rotary viscometer that vibrated sinusoidally in the same direction as the flow of the sample, and the optimum frequency for the speed fluctuation given to the sample was around 10 Hz. Or it was found to be in a frequency range slightly lower than 10 Hz. This result is different from the findings of the Stripa project,
In order to promote the practical use of the dynamic injection method, it is necessary to develop a new method and equipment based on the above results.

Grouting Apparatus S (See FIGS. 1 and 2) With reference to FIG. 1, the configuration of a dynamic injection system according to an embodiment of the rock grouting apparatus of the present invention will be described. here,
S is a rock grouting apparatus, which includes a grout material pumping unit 2 and a pulsating pressure generating unit 3 via a pumping piping line 1.
And a rock injection part 4.

[0013] pumping pipeline 1 pumping pipe line 1, the pipe 1a connecting grout pumping unit 2, a pulsating pressure generator 3 and the rock injection part 4 in each series,
It comprises a main piping system 1b and 1c, and a subordinate piping system of a piping 1d branched from the piping 1a in the grout material pumping section 2.

Grout material pumping section 2 Grout material pumping section 2 includes a grout material storage tank 10, an injection pump 11, a pressure sensor 12 and a pressure gauge 13, a flow sensor 14 and a flow meter 15, a return valve 1 through a pipe 1a.
6 and a controller 17. More specifically, first, the grout material produced by a mixing device (not shown) is stored in the grout material storage tank 10. 18 is an agitator. Then, it is sucked and pressurized by the injection pump 11 and sent out to the pressure feeding piping line 1. At this time, the pressure of the pressure feed pipe line 1 is detected by the pressure sensor 12 and the pressure gauge 13, and the opening of the return valve 16 and the rotation of the injection pump 11 are controlled via the controller 17 so that the pressure always keeps the specified value. Automatically control the number. As described above, the grout material pumping unit 2 includes the pulsating pressure generating unit 3 in the subsequent stage.
Has a function of forming a base quasi-stationary injection pressure component when applying a pulsating pressure and continuously feeding the material. Here, the flow sensor 14 and the flow meter 15 are used for monitoring the injection amount and determining the injection completion stage.

The rock injection part 4 bedrock injection unit 4, the injection tube 20, packer 21, is composed of a pressure sensor 22 and the on-off valve 23, under conditions of injection pressure pulsation pressure is added, the grout to crack the rock R The material is dynamically injected and penetrated. More specifically, the pressure sensor 22 is attached near the mouth of the injection pipe 20 and constantly detects a pulsating injection pressure waveform. The packer 21 needs to have a structure and material which have high rigidity of the seal portion and do not cause pulsating pressure damping as much as possible due to the property of applying pulsating pressure. It should be noted that the rock injecting section 4 in the figure is an example of a configuration of a standard packer method, and various changes can be made within a known configuration.

[0016] are those pulsation pressure generating portion 3 pulsation pressure generating portion 3 forming the central structure of the present invention, the hydraulic unit 25 in the present embodiment, an oscillator 26, a servo controller 27, the pulsation pressure generating pump 2
8. Pressure waveform detector 29, pressure fluctuation propagation suppression means 30
It is composed of Here, a check valve with high responsiveness is used as a means for suppressing propagation of pressure fluctuation. More specifically, the pulsating pressure generating pump 28 includes a hydraulic servo actuator 28A and a positive displacement pump 28B driven by the hydraulic servo actuator 28A (in the present embodiment, a piston pump is used). Inhaled and exhaled grouted material at the piston part,
The grout material is pumped to the rock injection part while adding a pulsating pressure having a specific frequency to the base quasi-stationary pressure.
That is, a signal waveform having a specific frequency and shape is oscillated using an oscillator 26 that oscillates a signal waveform such as a sine wave, a triangular wave, and a square wave, and detected by the pressure sensor 22 and the pressure waveform detector 29 of the rock injection part 4. The obtained pressure waveform is compared with a signal waveform instructed by the oscillator 26, and the operation of the hydraulic servo actuator is feedback-controlled so that both waveforms match. The amplitude of the pulsating pressure can be arbitrarily set within the range of the responsiveness of the entire pulsating pressure generating section 3 and the entire rock injection section 4 including the rock R by adjusting the amplitude (peak voltage) of the signal waveform. it can. The pulsating pressure is prevented from being propagated to the upstream side by the check valve 30 provided at the inlet pipe of the pulsating pressure generating pump 28.
It is provided only to the pressure feeding piping line 1 from the pulsating pressure generating pump 28 to the injection pipe 30. Servo controller 27
Are a comparison circuit 32, a servo amplifier 33, and a servo valve 34.
And precisely controls the hydraulic servo actuator 28A. Regarding the condition of the pulsation pressure, according to the above-mentioned vibration viscosity test and the dynamic injection test described later, several Hz to 30 H
The frequency range of z is effective, and pulsation around 10 Hz is determined to be optimal. Therefore, the signal waveform specified by the oscillator 26 is given a specific frequency selected from this range, and the control of the hydraulic servo actuator is usually easy and the grout material can be smoothly vibrated. A sine waveform shall be given.

In the present grouting apparatus S, the material is continuously pumped while forming a quasi-stationary injection pressure component as a base by using the injection pump 11 of the grout material pumping section 2. A mode in which the pump 11 is omitted is also included in the technical scope of the present invention. That is, it is also possible to directly suck the material from the grout material storage tank 10 into the piston portion of the pulsating pressure generating pump 28 and form a predetermined injection pressure including the pulsating pressure only by the pulsating pressure generating pump 28. In this case, the grout material is intermittently injected according to the volume of the piston part of the pulsating pressure generating pump 28, but the effect of the present invention is sufficiently exhibited although the working efficiency is slightly reduced.

FIG. 2 shows another embodiment which is a means for suppressing the propagation of pressure fluctuation. That is, in the present embodiment, a method of using the electromagnetic valve 36 that forcibly opens and closes in synchronization with the signal waveform of the oscillator 26 instead of the check valve will be described. In the present embodiment, in order to eliminate the response delay between the signal of the oscillator 26 and the pulsating pressure waveform, the signal of the oscillator 26 is adjusted by the delay circuit 37 and input to the solenoid valve 36 via the controller 38,
It is necessary to properly synchronize the generation cycle of the pulsating pressure and the opening / closing cycle of the solenoid valve. On the other hand, unlike the present embodiment, the air pressure and the oil pressure are controlled by an electromagnetic valve operated by the signal of the oscillator, and the control pressure is used as the pilot pressure to operate the on-off valve provided at the inlet pipe of the pulsating pressure generating pump. Is also effective.

Grouting Method Next, an embodiment of the rock grouting method according to the present invention, which is performed using the above-described grouting apparatus S, will be described.
First, in order to perform the grouting work, the grouting apparatus S is installed at a construction site. A grout injection hole H is previously drilled in the bedrock R at the construction site by drilling.
The interval between the grout injection holes H is usually set to 2 to 3 m, but may be appropriately changed according to conditions. Then, the injection pipe 2 of the rock injection section 4 of the grouting apparatus S is inserted into the injection hole H.
0 is inserted, and the front and rear packers 21 are expanded and pressed against the hole wall. Thus, leakage of grout from other than between the packers 21 is prevented.

Next, each operating mechanism of the apparatus S is started. That is, in the grout material pumping unit 2, the grout material storage tank 10 is mixed and the injection pump 11 is operated, and in the pulsation pressure generation unit 3, the hydraulic unit 25 is driven and the pulsation pressure generation pump 28 is prepared for driving. Make Then, the on-off valve 23 of the rock injection part 4 is opened.

In the grout material pressurizing section 2, the grout material is mixed in a grout material storage tank 10, sucked and pressurized by an injection pump 11, and sent out to a pressure feeding pipe line 1 a. At this time, the pressure in the pressure feed pipe line 1 is detected by the pressure sensor 12 and the pressure gauge 13, and the opening of the return valve 16 and the rotation of the injection pump 11 are controlled via the controller 17 so that the pressure always keeps the specified value. Automatically control the number. That is, when a pressure exceeding the specified value is detected, the return valve 16 is opened or the opening degree is increased, and the grout material is returned to the grout material storage tank 10 via the pipe 1d. Alternatively, the rotation speed of the infusion pump 11 is reduced. The flow rate sensor 14 and the flow meter 15 monitor the injection amount and determine the injection completion stage. As a result, when the pulsating pressure is applied in the pulsating pressure generating section 3, the grout material pumping section 2 forms a quasi-steady injection pressure component serving as a base and exhibits a function of continuously feeding the material.

In the pulsating pressure generator 3, the oscillator 26 oscillates a specific signal waveform, for example, a sine wave at a predetermined frequency, for example, 10 Hz, and sends it to the comparison circuit 32. The comparison circuit 32 receives a signal from the pressure sensor 22 of the rock injection unit 4 via the pressure waveform detector 29, compares a signal waveform based on the actually measured waveform with a signal waveform from the oscillator 26, and servos the comparison signal. Send to amplifier 33. In response to the deviation signal based on the comparison signal, the servo amplifier 33 operates the servo valve 34 so that both waveforms match, that is, the frequency and the amplitude match. As a result, the hydraulic servo actuator of the pulsation pressure generating pump 28 operates. Perform feedback control. The pulsating pressure generating pump 28 is a positive displacement pump (in this embodiment, a piston pump is used), and the grout material pumped from the grout material pumping unit 2 is sucked and discharged by the piston unit, and specified as a quasi-stationary pressure serving as a base. The grout material is pumped to the rock injection part while applying a pulsating pressure having a frequency of. Further, since the propagation of the pulsating pressure to the upstream side is suppressed by the check valve 30 provided at the inlet pipe portion of the pulsating pressure generating pump 28, the pulsating pressure generating pipe line 1 from the pulsating pressure generating pump 28 to the injection pipe 20. Limited to be given.

In the rock injection part 4, the grout material is injected into the rock R from between the front and rear packers 21 at a pressure obtained by superimposing a predetermined injection pressure and a pulsating pressure of a predetermined frequency.

Optimal frequency of dynamic injection test (see FIGS. 3 to 8) A dynamic injection test was carried out using the pulsating pressure generating pump according to the present invention and an artificial crack specimen, and the consistency with the vibration viscosity test was determined. And the effect of dynamic injection on static injection was verified. FIG. 3 shows an outline of the artificial crack specimen. Crack (opening width H: 5
(0 to 200 μm, channel width: 40 mm) was formed by sandwiching a copper foil having a predetermined thickness between two steel blocks, arranging 16 mm bolts at 75 mm intervals, and tightening with a constant torque.
Here, the surface of the steel block is smooth and parallel finished by hard chrome plating and polishing. For pressure measurement is the measurement hole T ₀ through T _4, the static pressure distribution in the original pressure and the crack in the injection port was measured. The pulsating pressure generating pump is [P (= P _c
± P _o ): 2 ± 1 MPa, flow rate: 0.02 to 31 cm ³
/ S, frequency f: 0 to 30 Hz], and a pulsating pressure approximating a sine wave was applied to the artificial crack specimen. Here, P is the pressure of the injection, the P _c average pressure, is P _o represents the amplitude components of the pulsation pressure. In this injection test, the grout material was directly injected from the pulsating pressure generating pump into the artificial crack specimen without using the injection pump of the grout material pumping section. The grout material was produced according to the above-mentioned vibration viscosity test, and the compounding water amount was (W / SF = 0.5, W / BE1 = 8, 10, W / B
E2 = 12,15). The average grout flow rate in the crack was calculated from the piston speed of the pulsating pressure generating pump. Further, when the grout was closed in the crack, the penetration distance of the grout was visually read after the test piece was opened.

FIG. 4 shows a measurement example of the pressure waveform (W / SF = 0.
5, H = 100 μm). At the crack entrance, a pulsating pressure approximately similar to a sine wave is formed. Under this test condition, the pulsating pressure is affected by a range of one to one from the crack entrance.
m is about m. FIG. 5 shows the relationship between the frequency f and the penetration distance as a BE2 test result. Where W /
In the test with BE2 = 12, H = 200 μm, the grout closed after passing through the crack. In the result of this figure, a clear peak value appears at f = 10 Hz, and the same result as the vibration viscosity test was obtained. Further, as the permeation distance at f = 10 Hz, a value obtained by adding about 1.5 m to the result of static injection (f = 0) was obtained. FIG. 6 shows the relationship between f and the average flow velocity U in the crack as test results of SF and BE1. Although not as clear as the result of the penetration distance above,
As a whole, a peak value is observed around 10 Hz. Further, according to the results of FIGS. 5 and 6, it can be seen that when f = 30 Hz, the result tends to approach the result of the static injection, and the effect of the pulsation is considerably reduced.

FIGS. 7 and 8 show the results of one-dimensional wave analysis for the injection test. Here, the sound speed a of the calculation condition was fixed at 1 km / s. FIG. 7 shows the pressure drop in the crack, that is, the distance x from the inlet and the pulsating pressure component P.
_o represents the relationship of the degree of attenuation, the viscosity is 100
Times (μ = 0.1 Pa.s) and 1000 times (μ = 1 Pa.s).
For s), it is an analysis result of the effect of the frequency f.
In the analysis, except for the impact pressure from the analysis waveform, extracting the maximum value Pmax and a minimum value Pmin of the quasi-sinusoidal waveform, and organized in [(Pmax -Pmin) / P _o]. According to the results, as f increases, the pulsation attenuates significantly, so it is considered that the range of use is around 20 to 30 Hz. FIG. 8 is an analysis example of the flow velocity fluctuation component at the entrance and the exit of the simulated crack. For f = 10 Hz and 20 Hz, the difference between the maximum value umax and the minimum value umin of the flow velocity, that is,
The relationship between [umax-umin] and viscosity is shown. According to the analysis results, the velocity uθ = 3 cm / s set in the above-described vibration viscosity test indicates that μ = 0.0 at the crack entrance (x = 0).
1 Pa. It is a velocity value formed in the grout material around s (100 times viscosity of water), and it can be said that it is an appropriate value to see the general characteristics of the vibration viscosity test.

As described above, the dynamic injection test can be summarized as follows. The result of the vibration viscosity test and the result of the dynamic injection test agreed well. Using the apparatus of the present embodiment, a pulsating pressure having a frequency as set and approximated to a sine wave could be stably generated. The high-concentration and high-viscosity grout material could penetrate into fine cracks having an opening width of about 100 μm. As a condition under which the effect of the dynamic injection is exhibited, that is, a condition of the pulsating pressure, a range of 0 Hz <frequency f ≦ 30 Hz was effective, and particularly, f = around 10 Hz was optimal.

As described above, according to the grouting method and the grouting apparatus according to the embodiment of the present invention, a pulsating pressure having an appropriate frequency and having a proper waveform is applied to a flowing grout material instead of an impact pressure wave. It can be given stably.
Further, the grout material can be continuously pumped by using both the infusion pump and the pulsating pressure generating pump. Further, the pressure fluctuation propagation suppressing means can generate pulsating pressure without being affected by the configuration on the upstream side of the pulsating pressure generating pump, and can effectively transmit this to the injection pipe. The device according to the present embodiment is small in size, excellent in portability, and quiet in operation.

According to the rock grouting method of the present invention, by applying a specific vibration (pulsating pressure) of 30 Hz or less under a predetermined pressure, the flow resistance of the grout material is significantly reduced. , Improved permeability to rock cracks,
It becomes possible to efficiently and quickly inject a high-concentration and high-viscosity grout material into a fine rock crack having a size of from 00 to 200 μm or less. As a result, the rock mass to be injected has a permeability of 10 ^-6 to
It can be expected that the state can be improved to 10 ⁻⁷ cm / sec or less. Furthermore, according to the rock grouting method of the present invention, it is possible to stably apply not a shocking pressure wave but a pulsating pressure having an appropriate frequency and a regular waveform to a flowing grout material. As a result, the entire grout material is subject to speed fluctuations, in other words, the constituent particles of the grout material are sufficiently excited, which contributes to an improvement in permeability. In addition, the secondary effect of the pulsating pressure can eliminate the phenomenon (clogging) in which the grout material is blocked in the rock crack.

[Brief description of the drawings]

FIG. 1 is a view showing an entire configuration of a construction apparatus according to an embodiment for implementing a method for constructing a rock grout according to the present invention.

FIG. 2 is a view showing another embodiment of the pressure fluctuation propagation suppression means of the present invention.

FIG. 3 is a diagram showing a configuration of an injection specimen having an artificial crack.

FIG. 4 is a view showing a measurement result of a pulsating pressure according to the present invention.

FIG. 5 is a diagram showing the relationship between frequency and penetration distance as a result of an injection test according to the present invention.

FIG. 6 is a graph showing the relationship between frequency and average flow velocity in a crack as a result of an injection test according to the present invention.

FIG. 7 is a diagram showing a relationship between a propagation distance and a degree of pulsation pressure attenuation as a result of wave analysis.

FIG. 8 is a diagram showing the relationship between viscosity and the degree of attenuation of flow velocity fluctuation as a result of wave analysis.

FIG. 9 is a side view showing an outline of a vibration viscosity testing device.

FIG. 10 is a side view, partly in plan, showing an outline of a vibration viscosity test apparatus.

FIG. 11 is a diagram showing the relationship between shear rate and shear stress as a result of a vibration viscosity test at a constant speed.

FIG. 12 is a view showing an apparent viscosity in a low shear rate region as a result of a vibration viscosity test at a constant speed.

FIG. 13 is a view showing the relationship between shear rate and shear stress as a result of a vibration viscosity test at a constant power.

FIG. 14 shows a prior art percussion drill type dynamic infusion pump.

[Explanation of symbols]

S: rock grouting equipment, 1 ... pumping piping line, 2 ...
Grout material pumping section, 3 ... pulsation pressure generating section, 4 ... rock injection section,

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Ohashi 4-55, Kodena-ku, Osaka, Osaka Prefecture Konoike Gumi Co., Ltd. (72) Inventor Yoshiyuki Sawa, 4-55, Konohana-ku, Osaka, Osaka No. Konoike Gumi Co., Ltd. (72) Inventor Takeo Nasu 15-17 Sakuragaokacho, Shibuya-ku, Tokyo Japan Basic Technology Co., Ltd.Tokyo Head Office (72) Inventor Yasutaka Terado 15-17 Sakuragaokacho, Shibuya-ku, Tokyo Japan Foundation (72) Inventor Tohru Takada 15-17 Sakuragaoka-cho, Shibuya-ku, Tokyo Japan Basic Technology Co., Ltd.

Claims (8)

[Claims] In grouting, a grout material is pumped at a predetermined injection pressure through a pressure feed pipe line, and the grout material is injected into an injection hole formed in a cracked rock with an injection pipe at an end thereof. A pulsating pressure having a specific frequency selected from a frequency range of 30 Hz or less is superimposed on the pressure,
A rock grouting method characterized by the following. 2. The method according to claim 1, wherein the frequency of the pulsating pressure is 1
Construction method of rock grout where 0Hz is selected. 3. In grouting for a cracked rock mass, grout material is pumped at a predetermined injection pressure, and a grouting line is inserted into an injection hole formed in the rock mass through an injection pipe at an end thereof. A pulsating pressure generating pump is interposed on the way, and the pulsating pressure generating pump generates a pulsating pressure having a specified frequency selected from a frequency range of 30 Hz or less and superimposedly adds the pulsating pressure to the injection pressure. A rock grouting method characterized in that: 4. The pulsating pressure generating pump according to claim 3,
A method for constructing rock grout which is periodically operated based on a signal waveform of an oscillator and driven by a servo control mechanism based on a comparison signal between an actually measured waveform in an injection pipe and the signal waveform. 5. A grouting method for a cracked rock mass, which is driven by a hydraulic servoactuator in the middle of a pressure feeding pipe line from an injection pump for feeding a grout material at a predetermined pressure to an injection pipe inserted into an injection hole. In addition to installing a positive displacement pulsating pressure generating pump, a means for suppressing the propagation of pressure fluctuations to the upstream side is provided at the inlet piping portion of the pulsating pressure generating pump, while a signal such as a sine wave, a triangular wave, and a square wave is provided. Using a servo control device including an oscillator that oscillates a waveform and a servo controller, comparing a pressure waveform detected by a pressure sensor attached near the mouth of the injection pipe with a signal waveform commanded by the oscillator, By performing feedback control of the operation of the hydraulic servo actuator so that both of the waveforms match, the pulsating pressure generating pump is controlled. A pulsating pressure having a specified frequency selected and selected from a frequency range of 30 Hz or less and approximated to a signal waveform, and the function of the pressure fluctuation propagation suppressing means is used to generate a pulsating pressure from the pulsating pressure generating pump to the injection pipe. The pulsating pressure is limited to the pressure feed pipe line up to and the pulsating pressure component is superimposed on the pressure of the infusion pump to improve the permeability of the grout material, and the grout material is densely and finely divided into fine cracks. A rock grouting method characterized in that it is injected quickly. 6. A method for constructing rock grout according to claim 5, wherein the injection pump is abolished and a predetermined pressure for feeding the grout material is obtained by the pulsating pressure generating pump. 7. An apparatus used in a method for dynamically injecting grout material by adding a pulsating pressure component to an injection pressure in grouting for a cracked rock mass, wherein the grout material is fed. A pumping pipe line, which is disposed at the downstream end of the pumping pipe line, is inserted into an injection hole, and allows a grout material to penetrate a crack in the rock, and is installed in the middle of the pumping pipe line, and is provided by a hydraulic servo actuator. A driven positive displacement pulsating pressure generating pump, means attached to the inlet pipe of the pulsating pressure generating pump, for suppressing the propagation of pressure fluctuations to the upstream side, and a pump for detecting the injection pressure. A pressure sensor mounted near the mouth, and a servo control device consisting of an oscillator that oscillates signal waveforms such as sine, triangle, and square waves, and a servo controller There are, by feedback controlling the operation of said hydraulic servo actuator as both waveform match by comparing the signal waveform command from the oscillator and pressure waveforms detected from the pressure sensor, 3
The pulsating pressure generating pump generates a pulsating pressure having a specific frequency selected and instructed from a frequency range of 0 Hz or less, and approximated to a signal waveform, and generates the pulsating pressure from the pulsating pressure generating pump to the injection pipe. And a pulsating pressure control means that is added only to the pressure feed pipe line. 8. An apparatus used in a method for dynamically injecting a grout material by adding a component of a pulsating pressure to an injection pressure in grouting for a cracked rock mass, wherein the grout material is fed. An injection pump disposed upstream of the pressure-feeding pipe line and feeding the grout material at a predetermined pressure; an injection pipe inserted into an injection hole to penetrate the grout material into cracks in the rock; A positive displacement pulsating pressure generating pump installed in the middle of a pressure feeding pipe line from a pump to the injection pipe and driven by a hydraulic servo actuator, attached to an inlet pipe of the pulsating pressure generating pump, and upstream of pressure fluctuation Means for suppressing propagation to the injection pipe, a pressure sensor attached near the mouth of the injection pipe to detect the injection pressure, and signals such as sine, triangle, and square waves. Using a servo control device including an oscillator that oscillates a waveform and a servo controller, a pressure waveform detected by the pressure sensor is compared with a signal waveform commanded by the oscillator so that both waveforms match. The feedback control of the operation of the hydraulic servo actuator
The pulsating pressure generating pump generates a pulsating pressure having a specific frequency selected and instructed from a frequency range of 0 Hz or less, and approximated to a signal waveform, and generates the pulsating pressure from the pulsating pressure generating pump to the injection pipe. And a pulsating pressure control means that is added only to the pressure feed pipe line.