JPH0362845B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the injection state of a chemical liquid when it is injected into the ground or bedrock using a gamma ray transmission method, and a method for managing chemical injection construction using the measuring method. .

Conventional methods for measuring the injection status of chemical solutions using radioisotopes (hereinafter abbreviated as RI) include methods using reflection-type neutron moisture meters or scattering-type (reflection-type) gamma-ray densitometers that use boron as a tracer. is being attempted. In the former method, a probe containing a fast neutron source and a thermal neutron detector is inserted into a chemical liquid injection hole (hereinafter referred to as the injection hole), and the chemical liquid is doped with boron or a boron compound as an indicator.
This system measures the amount of boron within a measurable range after injecting a chemical solution. This measurement method applies the diffusion phenomenon of thermal neutrons and the absorption of thermal neutrons by boron, so even if a strong radiation source is used, the measurement range is not wide, and the radius is 5 to 10 cm at most.
It is not possible to measure the average concentration of boron within the measurement range because it is strongly influenced only by the boron concentration near the probe. This means that only data with low accuracy can be obtained for the purpose of measuring the amount of drug solution injected. Furthermore, there is a drawback that the directionality of the drug solution injection state cannot be discriminated.

On the other hand, the latter reflection type gamma ray densitometer detects gamma rays that have been scattered once, so the directionality of the injection state can be determined by installing a collimator, but the measurable range is at most 5 to The measurement value is approximately 10 cm, and the measured value is dependent on the density distribution within the measurement range, so it cannot be said that it represents the average density.
As with the former method, the amount of liquid medicine to be injected cannot be measured accurately.

In this way, the conventional measurement method using a reflection-type measuring device using RI has a narrow measurement range of 5 to 10 cm, so in order to accurately determine the injection state, it is necessary to drill a large number of test holes at narrow intervals. In addition, the number of measurements increases accordingly, which requires a great deal of effort and time, and furthermore, the accuracy is essentially low.

The present invention was made with the aim of improving such conventional measurement methods, and by applying a transmission type gamma ray densitometer, it is possible to measure the average density within a narrow directivity range, thereby improving measurement accuracy and making it possible to measure the same. Since the distance can be increased, taking advantage of this advantage, the ground density before and after chemical injection is calculated between the injection hole and multiple test holes, and the density difference is calculated. The size and shape of the permeation area, that is, the state of distribution, are measured.

In addition, using this measurement method, we can measure the change in ground density over time during chemical injection, and also measure the type and density of the injected chemical liquid, the injection amount, and the injection pressure over time. This invention provides a method for managing chemical injection construction in which the injection condition of the chemical liquid is measured from the mode of change and the mode of change in the above-mentioned injection amount and injection pressure, and the injection conditions are adjusted while checking the injection state of the chemical liquid. .

This will be explained in detail below.

FIG. 1 is a cross-sectional view for explaining the principle of the transmission type gamma-ray densitometer applied in the present invention, in which 1 is a chemical injection hole (hereinafter simply referred to as injection hole), 2 is a γ-ray source, and 3 is a γ-ray source. 2 is housed in the tip and an insertion tube is inserted into the injection hole 1; 4 is a test hole drilled at a predetermined distance from the injection hole 1; 5 is a probe; A detector) 6 accommodates a high-voltage power supply 7 for feeding power and a preamplifier 8 for amplifying the output signal of the detector 6, and is inserted into the test hole 4 via a cable 9 with a signal line attached thereto. 10 is a counter that counts the gamma ray detection signal sent through the signal line, and 11 is a chemical liquid compacted soil in which the injected chemical liquid is solidified.

In the gamma-ray transmission type densitometer arranged in this way,
Of the γ-rays emitted from the γ-ray source 2, only the γ-rays that have passed through the ground are detected, so the measurement range is between the dashed-dotted line A-A' in FIG.
This is a narrow range sandwiched between dashed-dotted line B-B' in FIG. 2, which is a plan view taken from the line in FIG. In this way, since this device is a transmission type gamma ray densitometer, the measured values are as shown on the dashed-dotted lines A-A' and B.
It indicates the average density of the ground within the area surrounded by −B′, and the measurement range has good directionality (narrow spread), so it is different from the conventionally used scattering type.
Measurement accuracy is significantly improved compared to RI instruments. Also, if the distance between the γ-ray source 2 and the detector 5 is 50 cm,
100μCi of cobalt-60 is used as gamma ray source 2 and detector 6
If a GM tube is used for measurement, the density of the ground can be measured with the necessary accuracy in about 10 minutes.
If Ci is used, it is possible to measure with the necessary accuracy in about 1 minute.

Figure 3 shows how the present invention can be used in one shot method or 1.5
4 is a cross-sectional view of an embodiment applied to the shot method chemical injection method, and FIG. 4 is a plan view showing the arrangement of the test holes 4, where 12 is an injection pipe, 13 is a discharge hole for injecting chemical liquid, and 14 is a pressure-feeding chemical liquid. An injection pump 15 is provided at the distal end of the injection tube 12 and is configured to allow the gamma ray source 2 to be detachably attached thereto;
-1 to 4-6 are test holes provided at equal intervals on a circumference centered on injection hole 1, and in this example, test holes are provided so as to be located at each apex angle of a regular hexagon. 6-1
-6-6 are detectors inserted into each of the test holes 4-1 to 4-6, and the counter 10 is inserted into each of the test holes 4-1 to 4-6.
It is configured to separately count the detection signals sent from 1 to 6-6.

Next, the measurement procedure will be explained.

First, the density of the ground before chemical injection is measured. If a 10 mCi gamma ray source 2 is used and the distance between the ray source 2 and the detector 6 is 50 cm, the required accuracy can be measured in a measurement time of about 1 minute. Next, the injection of the chemical solution is started, and each detector 6 is
The counting rate of -1 to 6-6 is recorded at predetermined time intervals (1 minute in this example), and finally, the density is measured and recorded after the injection is completed. Such operations are repeated while pulling up the injection tube 12 and probe 5 by a predetermined length to complete the injection of the chemical liquid at a predetermined stage.

In this way, based on these data, it is possible to determine the mode of change in the density of the ground around the injection hole when the chemical is injected, the distribution state of the ground density before and after the chemical is injected, that is, the increase value, its positional relationship, and the three-dimensional relationship between the two. Since the relationships can be known, it is possible to accurately measure the injection state of the chemical solution, that is, the size and shape of the chemical injection compacted soil 11, from this information.

Depending on the type of ground, it may not be necessary to know how the density of the ground changes when the chemical is injected, but in this case, the density of the ground is measured three-dimensionally before and after the chemical is injected, and the chemical solution is measured three-dimensionally. If the amount of increase in ground density due to injection (hereinafter simply referred to as density difference value) is calculated, the density difference value will indicate the amount of chemical solution injected within the measurement range, so the injection hole can be determined from the distribution of this density difference value. It is possible to measure the injection state of the drug solution around 1. In this case, probe 5 is inserted into each test hole 4.
It goes without saying that the measurements may be made by sequentially inserting the signals within -1 to 4-6.

Furthermore, the measurement of the ground density difference value (that is, the amount of chemical injection) is not limited to the measurement between the injection hole 1 and the test hole 4. For example, as shown in FIG. Insert the γ-ray sources 2-1 and 2-4 into the detectors 6-2, 6-3, 6-5, and 6, respectively.
-6, test holes 4-1 and 4-2, 4-1 and 4-6, 4-4 and 4-
The density difference value between 3 and 4-4 and 4-5 can be calculated, and by changing the position of the γ-ray source 2 and the detector 6, the density difference value between all the test holes 4-1 to 4-6 can be calculated. A density difference value can be calculated. This test hole 4
By adding the form of the distribution of density difference values between -1 and 4-6, it is possible to measure the injection state of the chemical liquid with even greater accuracy, and furthermore, it is possible to measure the injection state of the chemical liquid over time between these test holes at the time of the chemical liquid injection. By measuring such changes and adding the manner of the changes, it is possible to measure the injection state of the drug solution with even higher accuracy.

In addition, when injecting chemical liquid, the third method is used to measure the ground density.
If the injection tube 12 shown in the figure is used, the gamma ray source 2 can be used separately.
This is convenient because there is no need to insert .

The injection pipe shown in FIG. 3 shows an embodiment that is applied to one shot method or 1.5 shot method construction, and FIG. 6 shows an embodiment of a two shot method injection pipe.

In the figure, 16 is the inner tube, 17 is the outer tube, and the inner tube 1
6 is formed with a discharge hole 13 and is provided with a radiation source attachment part 15 at its tip, and the outer tube 17 is a double tube with a metal crown 18 attached to the tip for drilling an injection hole. An injection tube 12 is configured. The injected chemical solution is supplied from the inner tube 16 to the curing agent, and from the outer tube 17
The base agents are pumped through the tubes, mixed at the tip of the outer tube 17, and injected into the ground through the discharge port 19.

Further, in the embodiment shown in FIG. 4, the test holes 4 are arranged so as to form a regular hexagon on the circumference centered on the injection hole 1, but the test hole 4 is not limited to this example, and other regular polygons may be formed. Also, the distance from the test hole and the interval between the test holes do not necessarily have to be the same. However, by arranging the test holes 4 in a regular polygon, it becomes easier to analyze planar ground density changes, and by arranging them symmetrically with injection hole 1 as the center, it is easier to analyze cross-sectional ground density changes. There are advantages to becoming

Further, in the above embodiment, an example was shown in which the radiation source mounting part 15 was disposed at the tip of the injection tube, but it goes without saying that the position is not limited to this.

Next, a method for managing chemical injection construction using the above-mentioned method for measuring the distribution state of an injected chemical will be explained.

As shown in FIG. 3, the gamma ray source 2 and injection tube 12 are inserted into the injection hole 1, and the surrounding test holes 4-1 to 4-4 are inserted into the injection hole 1.
-6 are respectively inserted with detectors 6-1 to 6-6 to measure changes in density of the ground before and after and during injection of the chemical solution. At the same time, the injection amount Q and injection pressure P of the chemical solution during injection are constantly measured, and the injection status is monitored by comparing the changes in these changes with the changes in the density of the ground during injection, and any abnormalities are detected. At that time, necessary adjustments were made.

For example, if there is no increase in the density of the ground at a certain injection stage, it is thought that there is a layer at that injection stage where the chemical solution easily escapes, and in this case, the gelation time should be shortened, and the injection pressure P and injection volume should be adjusted. By appropriately adjusting Q and pouring, construction can be carried out that suits the ground condition.

In addition to this example, whether or not the injection amount Q and injection pressure P are appropriate based on the manner in which the ground density changes over time when the chemical solution is injected, and the manner in which the injection pressure P and injection amount Q of the chemical solution change over time. Since it is possible to accurately measure the end of injection and to judge whether the gelling time of the injected chemical is appropriate, it is possible to carry out construction management that manages injection conditions while monitoring the permeation state of the chemical.

As explained in detail above, the present invention provides test holes at appropriate intervals around the chemical injection hole, inserts a gamma ray source into one of the holes, and inserts a gamma ray detector into the other hole. The density of the ground before and after chemical injection is measured and the density difference is calculated between each desired hole, and the distribution of these density differences determines whether the chemical has been injected into the ground. This is designed to measure the injection state of the chemical solution.Since the measurement is performed using a transmission type gamma ray densitometer, the measurement range is wide, the number of test holes can be reduced, and information on the directional distribution can also be obtained. Since the value is the average density within the measurement range, it also has the advantage of being able to accurately measure the amount of chemical solution injected into the ground. Therefore, it is possible to accurately measure the injection state of the chemical solution from the distribution state of the difference in the density of the ground between each hole before and after the chemical injection, and also to measure the change in the density of the ground between each hole when the chemical solution is injected. By comprehensively determining this aspect in addition to the distribution state of the density difference in the ground before and after the chemical injection, it is possible to measure the injection state of the chemical liquid with even higher accuracy.

In addition, by looking at changes in the density of the ground during the injection of the chemical solution, and changes over time in the injection pressure P and injection amount Q of the chemical solution, it is possible to distinguish injection conditions such as escape of the chemical solution, and depending on the injection state. It is possible to carry out appropriate construction management.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view for explaining the principle of the transmission type gamma ray densitometer applied in the present invention, Fig. 2 is a plan view showing the measurement range as seen from the line in Fig. A sectional view of one embodiment, Fig. 4 is a plan view showing the arrangement of the test holes, Fig. 5 is a plan view showing an arrangement example of another embodiment, and Fig. 6 is a plan view showing the arrangement of the test holes. FIG. 3 is a cross-sectional view showing the configuration of the tip portion of the example. Explanation of symbols, 1... Chemical injection hole, 2, 2-1,
2-4... γ-ray source, 3... Insertion tube, 4, 4-1~
4-6...Test hole, 5...Probe, 6,6-1
~6-6... γ-ray detector, 7... High voltage power supply, 8...
... Preamplifier, 9 ... Cable, 10 ... Counter, 11 ... Chemical injection compacted soil, 12 ... Injection pipe, 13
...Discharge hole, 14...Medical solution injection pump, 15...
Source attachment part, 16... Inner tube, 17... Outer tube, 18
...Metal crown, 19...Discharge port.

Claims (1)

[Scope of Claims] 1. Test holes are provided at appropriate intervals around the chemical injection hole, and a γ-ray source is placed in either the injection hole or the test hole, and a γ-ray detector is placed in any of the other holes. The work of inserting the chemical into the hole and measuring the density of the ground before and after injecting the chemical solution and calculating the density difference value is performed between each desired hole, and the density difference value is calculated based on the distribution of these density difference values. A method for measuring the injection state of a chemical solution that measures the injection state of a chemical solution injected into the ground. 2. Measure the change in the density of the ground between each hole over time when the chemical solution is injected, and measure the injection state of the chemical solution injected into the ground by taking into account the changes in the ground density between these holes over time. A method for measuring the injection state of a medicinal solution according to claim 1. 3. A patent claim in which a gamma ray source is inserted into the chemical solution injection hole, and a gamma ray detector is inserted into each test hole to measure the density of the ground between the chemical solution injection hole and each test hole. A method for measuring the injection state of a medicinal solution according to item 1. 4. A patent claim in which a gamma ray source is inserted into one of the test holes and a gamma ray detector is inserted into one or more of the other test holes to measure the density of the ground between both test holes. A method for measuring the injection state of a medicinal solution according to scope 1. 5. The method for measuring the injection state of a chemical liquid according to claim 1, wherein a plurality of test holes are provided at equal intervals on a circumference centered on the chemical liquid injection hole. 6 Insert a gamma ray source along with a chemical injection tube into the chemical injection hole, and insert a gamma ray detector into each of the multiple test holes provided around the injection hole to detect the density difference in the ground before and after chemical injection. In addition, we measured the change over time in the density of the ground at the time of injection between the injection hole and each test hole, and measured the change over time in the injection amount and injection pressure during chemical injection. A chemical liquid injection construction management method, characterized in that the injection state of the chemical liquid is measured from the temporal change in density and the change in the injection amount and injection pressure.