WO2023210029A1 - Method for checking mixing state of soil improving body - Google Patents

Abstract

This method involves: a first step for preparing cement slurry to which a water-soluble fluorescent dye is added; a second step for discharging the cement slurry from the base of a digging blade, digging surrounding dirt and mixing surrounding dirt and the discharged cement slurry, and forming an uncured soil improving body; a third step for irradiating, with black light from a light source provided to the digging blade, a soil improving body at a depth at which the digging blade is located inside the uncured soil improving body; and a fourth step for measuring, by a measuring device provided to the digging blade, the reflection of the black light at a depth at which the digging blade is located inside the uncured soil improving body.

Description

How to check the mixing status of soil improvement bodies

The present invention relates to a method for checking the mixing state of a soil improvement body that can accurately check the stirring and mixing status of the soil improvement body in real time in parallel with stirring and mixing when creating the soil improvement body in the ground.

As a ground improvement method, there is a deep mixing method that creates a ground improvement body in the ground by discharging cement slurry into the ground and mixing it with mechanical agitation. The ground improvement method creates a vertical columnar ground improvement body in the ground by stirring and mixing the earth and sand that make up the ground and cement slurry.

In the ground improvement method, after the soil improvement body is created, it is important to check whether the improvement material is stirred and mixed correctly (especially the distribution of cement slurry in the radial direction), and whether the created soil improvement body has the diameter as designed. becomes a problem. Since the ground improvement body exists underground, it is not easy to check its condition from the ground.

Normally, after the cement slurry has hardened in the constructed soil improvement body, check boring is performed to collect samples of the soil improvement body from the ground using a boring machine to confirm the condition of the soil improvement body.

However, in this case, a large number of other devices are required in addition to the boring machine, making the device large-scale. Therefore, the work cost is high, it is very laborious, and it takes a lot of time.

In view of this situation, Patent Document 1 (Japanese Unexamined Patent Publication No. 2009-102892) proposes that after a soil improvement body is created in the ground and before the improvement material hardens, a camera is attached to a pipe rod to take pictures of the inside of the ground. By inserting a rod with an attached camera and displaying the image of the ground taken by the camera on a monitor on the ground, workers can visually confirm whether or not there is improvement material. Suggest a method to check.

It is dark underground, and images displayed on monitors tend to be unclear, making it difficult for workers to make accurate judgments.

On the other hand, Patent Document 2 (Patent No. 6,944,605) discloses methods for (1) comparing the brightness of images taken before the improvement with images taken after the improvement, or (2) comparing the brightness of images taken before the improvement of the ground. We propose a method to check the condition of a ground improvement body by comparing it with known images of the condition.

According to this method, it is necessary to compare and process two or more image groups, and it is not possible to check the condition of the ground improvement body immediately after shooting, and accurate judgment depends on the color of the soil (dark color) and the degree of lighting. can be difficult. In particular, in (2), brightness and color tend to change due to differences in comparison positions, which poses a problem in comparison accuracy.

Furthermore, Non-Patent Document 1 (Japan Building Center "2018 Edition Improvement Ground Design and Quality Control Guidelines for Buildings") states that by spraying a phenolphthalein solution during a stirring condition test, an alkaline reaction (red-purple ) is described.

The discoloration of phenolphthalein is caused by alkaline conditions of pH > 10.0, and is based on the fact that phenolphthalein discolors in areas where cement is present, and indicates the state of cement mixing.

However, it is difficult to spray and observe phenolphthalein during the construction of a soil improvement body in the ground.

No matter which method is used, it is difficult to accurately check the stirring and mixing status of the soil improvement body in real time in parallel with the stirring and mixing when the soil improvement body is created in the ground.
Japanese Patent Application Publication No. 2009-102892 Patent No. 6944605 Japan Building Center "2018 Edition Design and Quality Control Guidelines for Improved Ground for Buildings"

Therefore, an object of the present invention is to provide a method for checking the mixing state of a soil improvement body, which can accurately check the stirring and mixing status of the soil improvement body in real time in parallel with the stirring and mixing.

The method for checking the mixing state of a soil improvement body according to the first invention is as follows:
A first step of preparing a cement slurry to which a water-soluble fluorescent dye is added;
A second step of discharging cement slurry from the base of the excavation blade, mixing the discharged cement slurry with surrounding earth and sand, and constructing an unhardened ground improvement body;
a third step of irradiating the ground improvement body with black light from a light source provided on the excavation wing at a depth where the excavation wing is located within the uncured ground improvement body;
and a fourth step of measuring the reflected light of the black light at a depth where the excavation blade is located in the unhardened ground improvement body using a measuring instrument provided on the excavation blade.

Here, according to the above configuration, it is possible to determine whether the mixing state is good or bad based on the reflected light of the black light measured by the measuring device while the ground improvement body is in an uncured state. At this time, there is no need to add large-scale equipment such as a boring machine. Moreover, even underground, the water-soluble fluorescent dye emits light smoothly when exposed to black light, allowing accurate recognition of its condition. Furthermore, the results will not become unstable due to complicated processing or disturbance elements.

Here, the measuring instrument may be a sensor that captures reflected light from the soil improvement body, or a camera that captures an image of the soil improvement body.

The wavelength of the black light is preferably 365 to 405 nanometers. In this way, a light source can be easily secured.

Further, it is preferable to determine the luminescence rate based on the output of the measuring instrument.

Furthermore, it is more preferable to compare the luminescence rate with a predetermined threshold value to determine whether the mixed state is good or bad.

It is preferable that the light source and the measuring device rotate along a circular trajectory centered on the rotation axis that rotates the excavation blade.

In this way, the positions of the light source and the measuring device within the rotational plane of the excavation blade are determined only by the rotation angle of the rotation axis, and stable measurements can be performed.

According to the present invention, a ground improvement body can be constructed while accurately checking the stirring and mixing status of an unhardened ground improvement body in real time in parallel with excavation and agitation in the ground where excavation and agitation is performed. Therefore, the condition of the ground improvement body can be checked at the current excavation location without being adversely affected by the photographing conditions, the color of the soil, the level of lighting, etc., and is highly effective in practical use.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a ground improvement device according to an embodiment of the present invention, FIG. 2(a) is a schematic block diagram of the same excavation agitation device, and FIG. 2(b) is a partially enlarged view of the same excavation agitation device. The cross-sectional view and FIG. 3 are plan views of the same excavation stirring device.

As shown in Fig. 1, this ground improvement device includes a base machine 1 that runs on the ground G, a leader 2 that stands up vertically, and a leader 2 that is movable up and down. A drive unit 10 that is instructed to include an actuator such as a motor, a rotating shaft 3 that is given rotational force by the drive unit 10 and rotates horizontally about a vertical axis underground, and a rotating shaft 3 that is attached to the lower end of the rotating shaft 3. and a stirring head 4.

Furthermore, a control unit 20 that controls the drive unit 10 is housed within the base machine 1.

FIG. 2(a) shows a portion of the ground improvement device shown in FIG. 1 that corresponds to the excavation stirring device. The control section 20 outputs a control signal S1 to the drive section 10 to control the operating state of the drive section 10. Further, the control unit 20 inputs a measurement signal S2 including a state quantity (for example, rotation speed, drive current, resistance value to rotation, etc.) indicating the operation of the drive unit 10, and grasps the operation state.

The stirring head 4 attached to the tip of the rotating shaft 3 is equipped with the following elements. First, at the lower end of the stirring head 4, there is provided an excavating blade 5 that has claws 5a for excavating underground and excavating earth and sand, and this excavating blade 5 is pivotally attached to the rotating shaft 3. Further, as shown in an enlarged view in FIG. 2(b), on the upper surface 5b of the excavating blade 5, at a position away from the center of the rotating shaft 3 by a radius r (see also FIG. 3), the excavating blade 5 A storage chamber 5c that opens upward is provided by drilling a part of the storage chamber 5c.

Inside the accommodation chamber 5c, a pair of a light source 6 and a measuring instrument 7 are housed, each facing upward. Note that the storage chamber 5c may be configured to open downward. The light source 6 may be any type of fluorescent lamp, incandescent lamp, mercury lamp, or LED that irradiates the ground improvement body with black light (wavelength: 365 to 405 nanometers) underground, but LEDs are small and easy to use. The measuring device 7 may be a sensor such as a fluorometer or a camera equipped with an image sensor, which measures the ground improvement body irradiated with black light from the light source 6. Note that the luminescence rate will be described later using FIGS. 5 and 6.

Furthermore, a transparent or translucent protective cover 8 is attached to the opening of the storage chamber 5c, so that the storage chamber 5c is sealed and the light source 6 and the measuring device 7 are protected from surrounding dirt, slurry, etc. be protected as such. The protective cover 8 can be suitably constructed from a resin plate such as acrylic or a tempered glass plate. Therefore, the light source 6 and the measuring device 7 move up and down integrally with the excavation blade 5.

As shown in FIG. 2(a), it is desirable that the stirring head 4 is provided with a stirring blade 12 and a co-rotation prevention blade 11 above the excavation blade 5, but these are not essential and may be omitted. . Here, when the stirring head 4 descends (when pulled down), the excavating blade 5 goes first, followed by the stirring blade 12 and the co-rotation prevention blade 11. Conversely, when the stirring head 4 moves up (when pulled up), the stirring blades 12 and anti-rotation blades 11 go first, and the excavating blades 5 follow last.

Next, details of the control section 20 will be explained with reference to FIG. 4. FIG. 4 is a block diagram of a control unit in an embodiment of the present invention. First, the light source 6, measuring device 7, drive section 10, etc. are as already described.

Of the control unit 20, the storage unit 24 includes a storage such as a memory or a hard disk for storing a control program for realizing operations according to the flowchart of FIG. 7 and various data to be temporarily stored.

The control unit main body 21 is composed of a processor and the like, and executes a control program stored in the storage unit 24 to control peripheral elements.

The monitor 23 is a display that displays the operating status to the user.

The state quantity measurement unit 25 measures predetermined state quantities (depth, rotation speed, rotation angle, drive current, resistance value to rotation, etc.) based on the measurement signal S2 received from the drive unit 10, and stores the measured state quantities in the storage unit 24. Store.

The control signal generation unit 27 generates a control signal S1 to be output to the drive unit 10, and stores it in the storage unit 24.

The interface 22 is controlled by the control unit main body 21 and inputs and outputs the control signal S1 and the measurement signal S2 to the drive unit 10, turns on/off the light source 6, and receives the measurement value (measurement signal) from the measuring device 7. input.

Next, the luminescence rate calculated by the luminescence rate calculation unit 26 will be explained with reference to FIGS. 5 and 6.

As already explained with reference to FIG. 3, the accommodation chamber 5c that accommodates the light source 6 and the measuring device 7 is located at a distance of radius r from the center of the rotation axis 3, and its width is t. The trajectory 15 of the storage chamber 5c is as shown in FIG. 6(a). In FIG. 6(a), the center O coincides with the center of the rotating shaft 3. In FIG.

Here, the luminous rate is the ratio (%) of the area where light is reflected, with the area hit by the black light emitted by the light source 6 being 100 (%), and is determined based on the measured value of the measuring device 7. Ru. In this embodiment, the luminescence rate is an index expressing the degree of mixing of the slurry and the earth and sand. Of course, the closer the luminescence rate is to 100 (%), the better the mixing degree is.

If the distance at which the measuring device 7 captures the reflected light is l with respect to the distance L (=2πr) that the storage chamber 5c goes around once, then
Luminous rate=(l/L)*100(%) (1)

If the angle at which the measuring device 7 captures the reflected light is θ (radian) with respect to the angle at which the storage chamber 5c makes one revolution (2π radian), then
Luminous rate = (θ/2π) * 100 (%) (2)

Either of the above equations (1) and (2) may be used, or other equations equivalent to these may be used.

Regardless of which formula is used, the state in Figure 6(a) is expanded linearly, the state where the measuring instrument 7 captures the reflected light is hatched, and the state where the measuring instrument 7 does not capture the reflected light If no hatching is applied to the area, if the luminance rate is 100 (%), the entire length will be hatched as shown in FIG. 6(b).

On the other hand, if the luminescence rate is 50(%), the state will be as shown in FIG. 6(c). Here, in order to facilitate understanding, the hatched state and the unhatched state are shown as being continuous. However, it is thought that the state in which the measuring instrument 7 captures the reflected light and the state in which the measuring instrument 7 does not capture the reflected light are usually interchanged at random. Therefore, it must be understood that even if a hatched state and a non-hatched state occur randomly, this falls within the scope of protection of the present invention.

As shown in Figure 5, when the coefficient of variation (=standard deviation/average value) of intensity due to needle penetration is taken on the vertical axis and the luminescence rate (%) is taken on the horizontal axis, the luminescence rate (%) is the maximum value (100 (%)), the coefficient of variation decreases.

In this embodiment, TH=80(%) is adopted as the threshold value for determining the quality of the luminescence rate (%). Needless to say, this numerical value is only an example, and it should be understood that even if a higher threshold value is used, it still falls within the protection scope of the present invention.

Incidentally, if the case where the luminous efficiency matches this threshold value TH=80 (%) is illustrated in the same manner as FIG. 6(c), the result will be as shown in FIG. 6(d). Here as well, as described above, it must be understood that even if a hatched state and a non-hatched state occur randomly, this falls within the protection scope of the present invention.

Next, with reference to FIGS. 7 and 8, the operation of the excavation stirring device and the operation management method of the device in this embodiment will be explained.

First, as shown in step 1 of FIG. 7, cement slurry is prepared as usual. The type of cement can be selected as usual, and there are no particular restrictions here.

Next, as shown in step 2 of FIG. 7, a water-soluble fluorescent dye is attached to the slurry. This point differs from the conventional method. Water-soluble fluorescent dyes include strontium fluoroborate (SrB4O7F:Eu2+, peak wavelength is 368-371 nm) with a trace amount of europium added, and barium silicide (BaSi2O5:Pb+, peak wavelength is 350-371 nm) with a trace amount of lead added. 353 nanometers), florescen, quinine sulfate, etc. can be suitably used.

More specifically, it is sufficient to use a commercially available fluorescent leakage testing agent (for example, Super Glow Fluorescent Leakage Testing Agent DF-300 (trademark) manufactured by Marktec Co., Ltd.), and it is sufficient to use fluorescent dyes against water. The concentration may be 0.05 to 20 (%). Note that there is usually no need to change the water-soluble fluorescent dye depending on the type of cement.

Next, as shown in step 3 of FIG. 7 and FIG. Rotate. In this way, the excavating blade 5 is brought to the initial depth H1.

Next, as shown in step 4 of FIG. 7 and FIG. 8(b), the slurry is discharged from the root of the excavation blade 5 downward from the initial depth H1, and excavation mixing is performed by the stirring head 4. Here, as mentioned above, unlike usual, since a water-soluble fluorescent dye is added to the slurry, the water-soluble fluorescent dye will be mixed in the ground improvement body to be constructed as well.

This state continues until the target depth H2 (the lowest part of the ground improvement body to be constructed) is reached, as shown in step 5 of FIG. 7 and FIG. 8(c).

When the excavating blade 5 reaches the target depth H2, as shown in step 6 of FIG. 7 and FIG. 8(d), the vertical movement of the rotary shaft 3 is switched from "lowering" to "raising".

Then, at the current position, the light source 6 is turned on and measurement is performed using the measuring instrument 7. When the rotating shaft 3 makes one revolution, the luminous rate R (%) calculated by the luminous rate calculation unit 26 and the threshold value TH (in this example, 80 (%)) stored in the storage unit 24 are calculated by the control unit main body. 21 compares. At this time, either of the above-mentioned equations (1) and (2) may be used, and further, equations equivalent to these may be used.

In step 8 of FIG. 7, if the luminescence rate R is less than the threshold TH, the control unit main body 21 determines that the step condition is not satisfied and maintains the current position without lifting the excavation head 4. In the prior art, it can be said that such a check did not work, and the drilling head 4 was moved carelessly even when mixing was inherently insufficient. According to the present invention, when mixing is insufficient, stopping the step and continuing mixing (this operation is rational) can contribute to improving the quality of the constructed soil improvement body. .

In step 8 of FIG. 7, if the luminous rate R is equal to or greater than the threshold value TH, the controller main body 21 determines that the stepping condition is satisfied, and pulls up the excavation head 4 to move the current position forward.

Of course, in the above, if the luminous rate R is equal to or less than the threshold TH, the control unit main body 21 determines that the stepping condition is not satisfied, or if the luminous rate R exceeds the threshold TH, the control unit main body 21 determines that the stepping condition is not satisfied. It should be understood that even if comparisons and substitutions well known to those skilled in the art are made, such as when the following conditions are satisfied, the invention still falls within the protection scope of the present invention.

In this way, when pulling up, the ground improvement body can be constructed while accurately confirming the fact that the mixing at the current position of the excavation head 4 is being performed well using the luminescence rate at the site itself. The practical effects can be said to be great. In addition, the lifting work will not be unnecessarily delayed due to measurement, comparison, etc. of luminous efficiency. On the other hand, with the conventional technology, it is virtually impossible to guarantee the quality of the mixing level at the same time as the soil improvement work.

This state continues to the initial depth H1 (steps 9 and 10 in FIG. 7), as shown in FIGS. 8(e) to 8(g), and finally reaches step 11 in FIG. As shown in (h), the ground return operation is performed.

[Amendment under Rule 91 21.06.2022]
A side view of a ground improvement device in an embodiment of the present invention (a) Schematic block diagram of an excavation agitation device in an embodiment of the present invention (b) Partially enlarged sectional view of an excavation agitation device in an embodiment of the present invention A plan view of an excavation stirring device in an embodiment of the present invention Block diagram of a control unit in an embodiment of the present invention Graph showing the relationship between luminescence rate and coefficient of variation in an embodiment of the present invention (a) Graph showing trajectories of the light source and measuring device in one embodiment of the present invention (b) Development diagram showing 100% luminescence rate in one embodiment of the present invention (c) In one embodiment of the present invention Developed view showing a luminous rate of 50% (d) Developed diagram showing a luminous rate of 80% in an embodiment of the present invention Flowchart showing the operation management operation of the ground improvement device in one embodiment of the present invention (a) Process explanatory diagram using an excavation stirring device according to an embodiment of the present invention (b) Process explanatory diagram using an excavation stirring device according to an embodiment of the present invention (c) Explanatory diagram of a process using an excavation stirring device according to an embodiment of the present invention (d) Process explanatory diagram using an excavation stirring device according to an embodiment of the present invention (e) Process explanatory diagram using an excavation stirring device according to an embodiment of the present invention (f) Process explanatory diagram using an excavation stirring device according to an embodiment of the present invention (g) An explanatory diagram of the process using the excavation agitation device in an embodiment of the present invention. (h) An explanatory diagram of the process using the excavation agitation device in an embodiment of the present invention.

1 Base machine 2 Reader 3 Rotating shaft 4 Stirring head 5 Excavation blade 5a Claw 5b Upper surface 5c Storage chamber 6 Light source 7 Measuring device 8 Protective cover 10 Drive unit 11 Co-rotation prevention blade 12 Stirring blade 15 Orbit 20 Control unit 21 Control unit main body 22 Interface 23 Monitor 24 Storage unit 25 State quantity measurement unit 26 Luminous rate calculation unit 27 Control signal generation unit G Ground surface S1 Control signal S2 Measurement signal t Width r Radius θ Angle H1 Initial depth H2 Target depth

Claims (7)

1. A first step of preparing a cement slurry to which a water-soluble fluorescent dye is added;
   a second step of discharging the cement slurry from the root of the excavation blade, excavating and mixing the discharged cement slurry with surrounding earth and sand to construct an unhardened ground improvement body;
   a third step of irradiating the ground improvement body with a black light from a light source provided on the excavation wing at a depth within the unhardened ground improvement body where the excavation wing is located;
   a fourth step of measuring the reflected light of the black light at a depth where the excavation blade is located within the unhardened ground improvement body using a measuring instrument provided on the excavation blade; and a mixed state of the ground improvement body. Confirmation method.
2. 2. The method for checking the mixing state of a soil improvement body according to claim 1, wherein the measuring device is a sensor that captures reflected light from the soil improvement body.
3. The method for checking the mixing state of a soil improvement body according to claim 1, wherein the measuring device is a camera that takes an image of the soil improvement body.
4. The method for checking the mixing state of a ground improvement body according to claim 1, wherein the wavelength of the black light is 365 to 405 nanometers.
5. The method for checking the mixing state of a ground improvement body according to claim 1, further comprising a fifth step of determining a luminescence rate based on the output of the measuring device.
6. The method for checking the mixing state of a ground improvement body according to claim 5, further comprising a sixth step of comparing the luminescence rate with a predetermined threshold value to determine whether the mixing state is good or bad.
7. The method for checking the mixing state of a ground improvement body according to claim 6, wherein the light source and the measuring device rotate along a circular orbit centered on a rotation axis that rotates the excavation blade.

Images