JP6405288B2 - Chemical injection method - Google Patents

Description

  The present invention relates to a chemical solution injection method for injecting a chemical solution into the ground.

  As disclosed in Patent Document 1, there is known a chemical solution injection method in which the injection rate or injection pressure of a chemical solution is dynamically changed and injected into the ground. According to this dynamic injection method, it is possible to widen the permeation range of the chemical solution and to improve the ground efficiently.

  Further, in Patent Document 2, when the dynamic injection method is applied to soft ground, a control waveform is generated by superimposing the periodic fluctuation of the short wave injection pressure on the periodic fluctuation of the long wave injection pressure. Thus, a method of performing injection according to the control waveform is disclosed.

  On the other hand, Patent Documents 3 and 4 describe that in the construction of a dam or a mountain tunnel, when the grout material is dynamically injected into the gap of the rock mass, control is performed to increase or decrease the amplitude of the injection pressure.

Japanese Patent No. 3731189 Japanese Patent Laid-Open No. 2008-231907 JP 2014-185469 A Japanese Patent Laid-Open No. 2004-197305

  However, if the chemical solution is continuously injected into the ground such as soft ground, the underground pressure gradually increases, and if the injection is continued without taking any measures, the ground may be raised.

  Therefore, an object of the present invention is to provide a chemical solution injection method capable of performing a predetermined amount of injection while controlling the penetration state of the chemical solution by controlling the injection method of the chemical solution.

  In order to achieve the above object, the chemical solution injection method of the present invention is a chemical solution injection method in which the injection rate or flow rate of the chemical solution is dynamically changed and injected into the ground, and the injection tube is installed on the target ground. And a step of performing injection by increasing / decreasing the injection rate or injection flow rate of the chemical solution to the injection tube, and the injection is performed when the injection pressure becomes a predetermined value or more, the average injection rate or the average injection flow rate. And the amplitude of the increase / decrease is reduced.

  Here, the amplitude of the increase / decrease when reducing the average injection rate or the average injection flow rate can be 5% -10% of the limit injection rate or the limit injection flow rate.

  Further, another chemical injection method of the present invention is a chemical injection method of injecting into the ground by dynamically changing the injection rate or injection flow rate of the chemical solution, the step of installing an injection tube on the target ground, Injecting by increasing / decreasing the injection rate or injection flow rate of the chemical solution to the injection tube, and repeating the increase / decrease by a predetermined number of cycles, and then injecting at a constant injection rate or injection flow rate. And thereafter repeating the increase / decrease by a predetermined number of cycles.

  Furthermore, another chemical injection method of the present invention is a chemical injection method for injecting into the ground by dynamically changing the injection speed or flow rate of the chemical solution, the step of installing an injection tube on the target ground, A step of performing injection by increasing / decreasing the injection rate or flow rate of the chemical solution to the injection tube, and the injection repeats an injection step of continuously performing an increase process and a decrease process of the increase / decrease amplitude. And

  In the chemical solution injection method of the present invention configured as described above, an injection pipe is installed on the target ground, and the injection speed or flow rate of the chemical liquid is increased or decreased from the injection pipe into the target ground.

  Then, when the injection pressure rises to a predetermined value or more, the injection is continued while decreasing the average injection speed or the average injection flow rate and decreasing the increase / decrease amplitude.

  For this reason, it is possible to prevent the underground pressure from rising uniformly, and it is possible to inject a predetermined amount of chemical solution such as a designed injection amount by continuing injection even after the increase.

  Further, by adopting an injection method that adjusts the injection speed and amplitude of the chemical solution while monitoring the underground pressure in this way, the infiltration state of the chemical solution is controlled, and the occurrence of unintended ground uplift can be suppressed.

  On the other hand, when dynamically injecting, after repeating the increase / decrease by a predetermined number of cycles, by interposing the injection at a constant injection speed, etc., the uniform increase in the underground pressure is suppressed, and the predetermined injection by the subsequent injection An amount of medicinal solution can be injected.

  In addition, when dynamically injecting, by adopting an injection method that repeats the injection step of continuously increasing and decreasing the amplitude of the increase / decrease of the injection, a uniform increase in the underground pressure is suppressed to a predetermined level. The medicinal solution can be injected until the amount is reached.

It is explanatory drawing for demonstrating the concept of the control waveform of the chemical injection method of embodiment of this invention. It is explanatory drawing which showed typically the structure of the apparatus used for a chemical | medical solution injection | pouring. It is explanatory drawing for demonstrating that injection pressure rises by continuing chemical | medical solution injection | pouring. It is explanatory drawing for demonstrating the concept of the control waveform of the chemical injection method of Example 1. FIG. It is explanatory drawing for demonstrating the concept of the control waveform of the chemical injection method of Example 2. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram for explaining the concept of control waveforms in the chemical solution injection method of the present embodiment.

  On the other hand, FIG. 2 is a diagram showing a schematic configuration of an apparatus used in the chemical injection method of the present embodiment. First, the structure of the dynamic infusion pump 2 and its surroundings will be described with reference to FIG.

  As a preparation process for injecting the chemical solution, the injection pipe 1 is installed on the ground G using the boring machine 4. Here, when the injection tube 1 also serves as a drilling rod, the swivel head 11 of the boring machine 4 is connected to the head of the injection tube 1, and the injection tube 1 driven into the target ground is used as a chemical solution. Used for injection.

  On the other hand, when a dedicated drilling rod (not shown) is used, the drilling rod is first connected to the swivel head 11 of the boring machine 4, and the drilling rod is injected after the drilling is completed. It replaces with the pipe | tube 1 and will perform chemical | medical solution injection | pouring.

  The swivel head 11 is connected to a dynamic infusion pump 2 capable of performing a chemical liquid injection method of increasing or decreasing the chemical liquid injection speed, injection flow rate, or injection pressure with time. That is, the dynamic injection pump 2 is a pump capable of dynamic injection that changes the injection speed, the injection flow rate, or the injection pressure over time.

  The dynamic infusion pump 2 is mainly composed of an infusion pump 21 having an electric motor as a drive unit, a waveform generator 22 serving as a function generator, and a flow rate / pressure measuring device 23.

  The injection pump 21 can change the discharge flow rate (injection flow rate) by arbitrarily changing the rotation speed of the electric motor. Here, the value obtained by dividing the discharge flow rate by the cross-sectional area of the pipe used for feeding the chemical solution is the injection speed.

  For this reason, when the rotation speed of the electric motor is lowered, the injection speed is lowered accordingly. On the other hand, when the rotational speed of the electric motor is increased, the injection speed is increased accordingly.

  The waveform generator 22 is a device that creates a control waveform such as a SIN wave (sine wave), for example. The waveform generator 22 can adjust the frequency f and amplitude of the waveform. Here, the amplitude is the difference between the maximum flow rate and the minimum flow rate (the difference between the maximum injection rate and the minimum injection rate, the difference between the maximum injection pressure and the minimum injection pressure).

  Furthermore, the flow rate / pressure measurement device 23 is a device that measures the flow rate and injection pressure of the chemical solution injected into the target ground (ground G) by the injection tube 1. From the flow rate value (L / min) measured by the flow rate / pressure measuring device 23, the injection flow rate (injection speed) of the chemical solution injected into the target ground can be grasped.

  In addition, the underground pressure can be estimated from the pressure value (kPa) measured by the flow rate / pressure measuring device 23. For example, when the pressure value measured by the flow rate / pressure measuring device 23 is increasing, it can be estimated that the underground pressure in the target ground is also increasing.

  The chemical solution injected by the dynamic injection pump 2 includes known chemical solution injection methods such as water glass solution type chemical solution, bentonite, high-concentration fine grout containing ultrafine cement, and mortar grout mixed with coarse particles. Various kinds of chemicals used in the above can be used.

  In addition, depending on the type of the chemical liquid to be injected, there are a liquid that is pumped immediately after mixing the two liquids, a liquid that is pumped in the state of one liquid, and the like. In FIG. 2, the structure which pumps immediately after mixing two liquids (A liquid, B liquid) is demonstrated.

  A chemical liquid mixer 3 is connected to the dynamic infusion pump 2. In the chemical liquid mixer 3, two liquids (A liquid and B liquid) are mixed. That is, the hardener (the raw material of the B liquid) conveyed from the hardener storage site 31, the water sent from the water storage tank 32, and the solution (A liquid) sent from the liquid storage tank 33 are contained in the chemical liquid mixer 3. Mix with.

  The curing material storage 31 is appropriately replenished with the curing material that has been carried to the site by the transport vehicle 311 or the like. Further, the water stored in the water storage tank 32 is supplied to the chemical mixer 3 by the water pump 321.

  Further, the solution transported by the tank lorry 333 or the like is stored in the liquid storage tank 33 and supplied to the chemical liquid mixer 3 by the liquid feed pump 331. Here, the amount of the solution supplied to the chemical mixer 3 is managed by the flow meter 332.

  Next, knowledge that is a premise for explaining the injection method of the chemical solution injection method of the present embodiment will be described with reference to FIG.

  The upper part of FIG. 3 shows a control waveform S of a sine wave that is injected at an average injection speed S0 with the difference between the maximum injection speed S1 and the minimum injection speed S2 as an amplitude. This control waveform S represents the instantaneous injection rate.

  In the dynamic injection method, the chemical solution is injected into the ground G while increasing / decreasing the injection speed by such a control waveform S. On the other hand, an injection pressure P indicating the underground pressure of the ground G is shown in the lower part of FIG.

  If the chemical liquid injection is continued, the chemical liquid is filled in the gap of the ground G, so that the injection pressure P gradually increases. Then, while the injection pressure P continues to rise, if the injection is continued with the same control waveform S, the control value P1 at which the possibility of the ground G to rise will eventually be exceeded. Therefore, in the chemical solution injection method according to the present embodiment, the injection method described below is applied.

  Next, the process and the operation of the chemical solution injection method according to the present embodiment will be described with reference to the drawings.

  First, as shown in FIG. 2, the injection tube 1 is driven to a predetermined depth of the ground G using a boring machine 4. Although not shown in the figure, a large number of injection pipes 1,... Are actually installed on the ground G with a wide area.

  And the chemical | medical solution is inject | poured in the ground G using the installed injection pipe 1. FIG. First, the dynamic injection method will be described with reference to the left part of FIG.

  Injection from the injection tube 1 is performed by increasing or decreasing the injection rate over time. Here, if the cross-sectional area of the pipe used for feeding the chemical liquid is constant, the change in the injection speed is the same as the change in the injection flow rate (L / min).

  For this reason, “managing with the injection rate” and “managing with the injection flow rate (discharge flow rate)” can be synonymous. Therefore, the injection rate can be managed by the measurement value of the flow rate / pressure measurement device 23.

  The average injection speed LS0 can be adjusted by changing the number of rotations of the injection pump 21. This average injection rate LS0 can be set to a limit injection rate, for example.

  The limit injection rate is a value at which it is said that a sufficient improvement effect can be obtained if the chemical injection method is less than this value. Various methods have been proposed for determining the limit injection rate. For example, it can be obtained from the result of an in-situ test in which water is injected into the ground G. As a concept, the limit injection rate can be a boundary value at which a transition from an injection rate mainly composed of osmotic injection to an injection rate mainly composed of split injection.

  On the other hand, the increase / decrease of the injection rate can be adjusted by the waveform generator 22. At the beginning of injection, a control waveform is a sine wave whose amplitude is the difference between the maximum injection speed LS1 and the minimum injection speed LS2. The waveform generator 22 also sets the frequency f (wavelength λ).

  The magnitude of the control waveform amplitude (LS1-LS2) at the beginning of the injection can be increased to, for example, 15% -20% of the average injection speed LS0 (limit injection speed).

  On the other hand, the underground pressure of the ground G during injection can be grasped by the injection pressure measured by the flow rate / pressure measuring device 23. When the injection pressure increases and becomes a predetermined value or more (for example, the management value P1 or more), the control waveform is changed.

  The right side of FIG. 1 shows the control waveform after the change. In the change, the number of revolutions of the infusion pump 21 is lowered to lower the average infusion rate SS0. Then, the waveform generator 22 is operated to reduce the amplitude of the control waveform (maximum injection rate SS1−minimum injection rate SS2).

  The magnitude of the control waveform amplitude (SS1-SS2) after the change is reduced to, for example, 5% -10% of the average injection speed LS0 (limit injection speed) at the beginning of injection.

  As a result, a uniform increase in the injection pressure is suppressed, and the injection pressure becomes smaller than the control value P1. On the other hand, the injection of the chemical solution can be continued until a predetermined injection amount is reached.

  In the chemical solution injection method of the present embodiment configured as described above, the injection tube 1 is installed on the target ground, and the injection rate (injection flow rate) of the chemical solution is increased or decreased from the injection tube 1 into the target ground. Do.

  When the injection pressure increases to the control value P1 or more, the average injection speed is reduced from LS0 to SS0 by decreasing the rotation speed of the injection pump 21. Further, the waveform generator 22 is operated to reduce the increase / decrease amplitude from (LS1-LS2) to (SS1-SS2).

  In this way, by controlling both the amount (injection speed) and the pressure (injection pressure) of the chemical solution injection, it is possible to prevent the underground pressure from rising uniformly, and the underground pressure once The infusion can continue after rising. As a result, it is possible to inject a predetermined amount of chemical solution such as a design injection amount to the end.

  Also, by adopting an injection method that adjusts the injection speed and amplitude of the chemical while monitoring the underground pressure in this way, the infiltration state of the chemical is controlled so that the underground pressure does not become too high, and the unintended ground Generation | occurrence | production of the protrusion of G can be suppressed.

  And since it inject | pours a chemical | medical solution continuously, reducing injection | pouring speed | velocity | rate, it can inject | pour a chemical | medical solution in a short time and is excellent in construction efficiency.

  Hereinafter, Example 1 of a form different from the chemical injection method described in the above embodiment will be described with reference to FIG. Note that the description of the same or equivalent parts as the contents described in the above embodiment will be described using the same terms or the same reference numerals.

  In the above-described embodiment, the injection method for reducing the average injection speed and the amplitude after the increase of the underground pressure has been described. However, in the first embodiment, static injection with a constant injection speed is sandwiched between dynamic injections. The chemical injection method will be described.

  FIG. 4 is an explanatory diagram for explaining the concept of the control waveform of the chemical injection method according to the first embodiment. First, dynamic injection is performed using a control waveform having an average injection rate S0, a maximum injection rate S1, a minimum injection rate S2, and a period T.

  This dynamic injection is performed for two periods (2T, two cycles). Thereafter, the static injection with the average injection speed S0 and the injection speed constant is performed for a length (0.5T) that is half the period T of the dynamic injection.

  Then, again, dynamic injection is performed for two periods (2T, two cycles) with a control waveform having an average injection speed S0, a maximum injection speed S1, a minimum injection speed S2, and a period T.

  The injection can be continued by repeating the static injection and the dynamic injection thereafter until the design injection amount is reached. Note that the length of one-step dynamic injection (period T, number of cycles) and the length of static injection can be arbitrarily set.

  The chemical injection method according to the first embodiment configured as described above repeats the increase / decrease of the injection rate at a predetermined number of cycles (2T), and then inserts the injection at a constant average injection rate S0, so that the underground pressure is reduced. By suppressing the uniform increase, the injection of a predetermined amount of a chemical solution such as the designed injection amount can be performed to the end by the subsequent injection.

  Other configurations and operational effects of the first embodiment are substantially the same as those of the above-described embodiment and other embodiments, and thus description thereof is omitted.

  Hereinafter, Example 2 of a form different from the chemical solution injection method described in the embodiment or Example 1 will be described with reference to FIG. Note that the description of the same or equivalent parts as those described in the above embodiment or Example 1 will be described using the same terms or the same reference numerals.

  In the above-described embodiment, the injection method for reducing the average injection speed and the amplitude after the increase in the underground pressure has been described. The chemical solution injection method to be performed will be described.

  FIG. 5 is an explanatory diagram for explaining the concept of the control waveform of the chemical injection method according to the second embodiment. In the control waveform of dynamic injection performed here, there are two processes of an increasing process in which the amplitude gradually increases and a decreasing process in which the amplitude gradually decreases in one injection step ST.

  The average injection rate S0 of Example 2 is always constant. For example, the average injection rate S0 is set to the limit injection rate. On the other hand, at the beginning of the injection step ST, the maximum injection speed XS1 and the minimum injection speed XS2 are the smallest. For this reason, the amplitude of the injection rate (maximum injection rate XS1-minimum injection rate XS2) is also the smallest.

  This amplitude gradually increases as time t elapses. In the center of the injection step ST, the maximum injection speed YS1 and the minimum injection speed YS2 are the largest. For this reason, the amplitude of the injection rate (maximum injection rate YS1−minimum injection rate YS2) is also the largest.

  The magnitude of this maximum amplitude (YS1-YS2) can be, for example, 15% -20% of the critical injection rate. In this injection method, a split vein is formed in the ground in the increasing process up to the maximum amplitude.

  After reaching the maximum amplitude, the amplitude gradually decreases. In the process of decreasing the amplitude, the injection range of the chemical solution in the ground is expanded. From such an increase in amplitude to a decrease (increase process and decrease process) is defined as one injection step ST. For example, the length of one injection step ST can be set to 15 seconds or less.

  FIG. 5 shows a state where the injection step ST is repeated twice. This injection can be continued by repeating the injection steps ST,... Until the designed injection amount is reached. The length of the injection step ST can be set arbitrarily.

  The chemical solution injection method according to the second embodiment configured as described above is an injection method that repeats the injection step ST in which the increase process and the decrease process of the increase / decrease of the injection are continuously performed, so that the ground pressure is uniform. The injection can be carried out until the end of the injection of a predetermined amount of chemical solution such as the design injection amount.

  In addition, about the other structure and effect of Example 2, since it is substantially the same as the said embodiment or another Example, description is abbreviate | omitted.

  The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to the embodiment and the example, and the design change is within a range not departing from the gist of the present invention. Are included in the present invention.

  For example, in the embodiments and examples described above, the case where the injection management is performed at the injection speed has been described. However, the present invention is not limited to this, and the injection management can be similarly performed according to the injection flow rate.

  In the above-described embodiment and examples, the case where the injection speed is increased / decreased with a sine wave has been described. However, the present invention is not limited to this, and various waveforms such as a rectangular waveform and a sawtooth waveform are used as control waveforms. Can do.

1 Injection pipe G Ground P Injection pressure P1 Control value (predetermined value)
LS0, SS0 Average injection speed LS1, SS1 Maximum injection speed LS2, SS2 Minimum injection speed T Period (cycle)
S0 Average injection speed S1 Maximum injection speed S2 Minimum injection speed ST Injection step XS1 Maximum injection speed XS2 Minimum injection speed YS1 Maximum injection speed YS2 Minimum injection speed

Claims (3)

A chemical solution injection method for dynamically changing the injection rate or flow rate of a chemical solution and injecting it into the ground,
Installing the injection tube on the target ground;
Injecting by increasing or decreasing the injection speed or injection flow rate of the chemical solution with respect to the injection tube,
The injection is a method of reducing the amplitude of the increase / decrease while reducing the average injection rate or the average injection flow rate when the injection pressure becomes a predetermined value or more ,
A chemical injection method characterized in that the amplitude of the increase / decrease when reducing the average injection rate or the average injection flow rate is 5% -10% of the limit injection rate or the limit injection flow rate . A chemical solution injection method for dynamically changing the injection rate or flow rate of a chemical solution and injecting it into the ground,
Installing the injection tube on the target ground;
Injecting by increasing or decreasing the injection speed or injection flow rate of the chemical solution with respect to the injection tube,
The injection is performed by repeating the increase / decrease at a predetermined number of cycles, then performing injection at a constant injection rate or flow rate, and thereafter repeating the increase / decrease at a predetermined number of cycles. A chemical solution injection method for dynamically changing the injection rate or flow rate of a chemical solution and injecting it into the ground,
Installing the injection tube on the target ground;
Injecting by increasing or decreasing the injection speed or injection flow rate of the chemical solution with respect to the injection tube,
The chemical injection method according to claim 1, wherein the injection repeats an injection step in which an increase process and a decrease process of the increase / decrease amplitude are continuously performed.