JP6850624B2 - Construction status confirmation method of high-pressure injection agitator and construction method of ground improvement body using this method - Google Patents

Description

The present invention relates to a technique for confirming the construction status of a high-pressure jet agitator.

Conventionally, as a technique for confirming the construction status of a high-pressure injection agitator, for example, there is a technique disclosed in Patent Document 1. In this technique, a plurality of vertical holes are formed around the injection pipe inserted in the ground at different distances from the injection pipe, a built-in pipe is inserted into the vertical holes, and a sealing material is placed around the vertical holes. The built-in pipe is fixed by filling. After that, a detector for detecting the vibration generated by the built-in pipe is vertically installed in the built-in pipe, and then, the cured material is injected at high pressure from the injection nozzle of the injection pipe, and the vibration at that time is detected by the detector. Then, by monitoring this detection result, the cutting state of the ground is confirmed. In such a technique, a sound collecting microphone is used as a detector. In addition, by pulling up the sound collecting microphone with the raising device in synchronization with the pulling speed of the injection pipe, the sound collecting microphone is moved according to the injection position of the hardened material, and the sound of the hardened material hitting the built-in pipe is heard. It is possible to clearly monitor with a sound collecting microphone.

Japanese Unexamined Patent Publication No. 2012-62626

However, in the method of Patent Document 1, since the sound collecting microphone moves and its height position changes, it is difficult to grasp the exact arrival position of the injection nozzle in the height direction. Therefore, it is difficult to grasp the construction status such as the pulling speed (actual speed) of the injection pipe, which requires accurate reaching height position information of the injection nozzle.
In addition, since a common sound collecting microphone is used for multiple soil layers with different soil qualities and the sound of the hardening material hitting the built-in pipe is monitored while moving, the cause of the change in the collected sound is the soil. It is difficult to grasp the construction status of each soil layer, such as whether it is due to straddling the layers or other causes (such as non-arrival of injection in the radial direction).

Therefore, the present invention has been made by paying attention to the unsolved problems of such conventional techniques, and the accuracy of the specific height position of each soil layer constituting the ground portion for creating the ground improvement body is accurate. and its object is to provide a Do construction status confirmation method of a high-pressure jet stirred Engineering capable of confirming the construction status and reclamation how the ground improvement body using this method.

In order to achieve the above object, the method for confirming the construction status of the high-pressure injection stirrer according to the first aspect of the present invention is to inject the cured material at high pressure from the injection nozzle of the improved pipe inserted in the ground and the improved pipe. This is a method of confirming the construction status of a high-pressure injection agitator that creates a ground improvement body by pulling it up while rotating. It is a method of confirming the construction status of a high-pressure injection agitator, in the radial direction from the construction position before the construction of the ground improvement body. An observation hole drilling step of drilling an observation hole at a position separated by a preset distance, an external tube construction step of building an external tube in the observation hole, and the above-mentioned inside the external tube. At least an acceleration sensor that detects vibration transmitted via the external pipe is installed at each depth position corresponding to the position of each soil layer of the plurality of types of soil layers constituting the ground portion where the ground improvement body is constructed. After the sensor placement step of fixing and arranging one by one and the sensor placement step, the cured material is injected at high pressure from the injection nozzle, and the vibration transmitted through the external pipe by this high pressure injection corresponds to each soil layer. A vibration recording step of detecting with each of the acceleration sensors fixedly arranged at each depth position and recording vibration data indicating the detection result, and the high-pressure injection stirring based on the vibration data recorded by the vibration recording step. seen including a construction status confirmation step of confirming construction status of engineering, and the observation hole is construction depth than a depth of the soil improvement material, said outer intubation above construction depth of the soil improvement material It is a length, and in the sensor arranging step, a long support member having a length equal to or longer than the construction depth of the ground improvement body and a length position corresponding to the depth position of each soil layer of the support member. A sensor support having a plurality of the acceleration sensors arranged in each of the above is inserted into the external tube, and after the insertion, the inside of the external tube is filled with a vibration transmitting substance which is a substance capable of transmitting vibration. Is what you do.
Further, in order to achieve the above object, another aspect of the method for confirming the construction status of the high-pressure injection stirrer according to the first aspect of the present invention is to apply high pressure to the hardened material from the injection nozzle of the improved pipe inserted in the ground. This is a method of confirming the construction status of a high-pressure injection agitator that creates a ground improvement body by injecting and pulling up the improved pipe while rotating it. An observation hole drilling step of drilling an observation hole at a position separated by a preset distance in the radial direction from the construction position, an external tube construction step of building an external tube in the observation hole, and the outside Vibration transmitted via the external intubation is applied to each of the depth positions corresponding to the positions of the respective soil layers of the plurality of types of soil layers constituting the ground portion formed by the ground improvement body inside the intubation. A sensor arranging step in which at least one acceleration sensor to be detected is fixedly arranged, and a vibration transmitted by high-pressure injection of a cured material from the injection nozzle after the sensor arranging step and transmitted through the external tube. A vibration recording step of detecting with each of the acceleration sensors fixedly arranged at a depth position corresponding to each of the soil layers and recording vibration data indicating the detection result, and the vibration data recorded by the vibration recording step. The observation hole has a depth equal to or greater than the construction depth of the ground improvement body, and the external pipe is the ground improvement body. In the sensor placement process, a long support member having a length equal to or longer than the construction depth and having a length equal to or longer than the construction depth of the ground improvement body and the depth position of each soil layer of the support member A sensor support having a plurality of the acceleration sensors arranged at least one at a corresponding length position is fixedly arranged so that the sensor support is in contact with the inner surface of the external tube. It is installed in the intubation.

Further, in order to achieve the above object, in the method for creating the ground improvement body according to the second aspect of the present invention, the hardened material is injected at high pressure from the injection nozzle of the improvement pipe inserted in the ground, and the improvement pipe is injected. The high pressure according to the ground improvement body construction step of creating the ground improvement body by the high pressure injection agitator which creates the ground improvement body by pulling up while rotating, and the construction status confirmation method of the high pressure injection agitator according to the first aspect. Includes a construction status confirmation process for confirming the construction status of the jet stirrer.

According to the present invention, at least one acceleration sensor is fixedly arranged at a depth position corresponding to the position of each soil layer constituting the ground portion for creating the ground improvement body in the observation hole, and these are fixedly arranged. Each accelerometer is used to individually detect the vibration generated in the external tube at each soil layer position. As a result, as the construction status information of the high-pressure injection stirring method, it is possible to measure the vibration data of the vibration transmitted via the intubation to the acceleration sensor arranged at the depth position of each soil layer at the time of constructing the ground improvement body. It will be possible. In addition, it is possible to confirm the more accurate construction status in each soil layer where the acceleration sensor is placed based on the measured vibration data. In addition, by reflecting this confirmation result in the construction contents, it is possible to create a higher quality ground improvement body.

(A) to (c) are diagrams showing an example of the flow of the construction status confirmation method and the ground improvement body construction method of the high-pressure injection agitator according to the first embodiment, and are views in which the intubation tube is transparently displayed. .. It is a figure which shows an example of the composition of the soil layer of the ground improvement part, the pulling speed of an improvement pipe, the required improvement diameter, and the arrangement position of an acceleration sensor. (A) to (d) are views for explaining the structure of the sensor support and the mounting structure of the acceleration sensor, and (a) is a view of a part of the sensor support viewed from the front side and the side surface side. , (B) is a partially enlarged view including the rivet portion of (a), (c) is a partially enlarged view of the sensor mounting portion of (a) viewed from the side surface side and the back surface side, and (d) is a partially enlarged view. It is sectional drawing of the line AA of (a). It is a block diagram which shows the specific structure of the measuring apparatus which concerns on 1st Embodiment. (A) to (c) are diagrams showing an example of a procedure for forming a ground improvement body. (A) to (c) are waveform diagrams showing an example of the vibration waveform of the vibration detected by the first to third acceleration sensors. (A) to (c) are views in which a part of each vibration waveform of FIG. 6 is cut out and enlarged. (A) to (b) are diagrams showing a configuration example of the second intubation according to the second embodiment, and (c) to (d) are diagrams for explaining the effect at the time of pulling out. .. It is a figure which shows an example of the installation structure of the sensor support which concerns on the modification.

Next, the first and second embodiments of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the vertical and horizontal dimensions and scale of the members or parts may differ from the actual ones. Therefore, the specific dimensions and scale should be judged in consideration of the following explanation. In addition, it goes without saying that there may be parts in which the relations and ratios of the dimensions of the drawings are different from each other.
Further, the first and second embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the material of a component. The shape, structure, arrangement, etc. are not specified as follows. The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims stated in the claims.

(First Embodiment)
The high-pressure injection stirring method is one of the ground improvement body construction methods in which a liquid hardening material is jetted in the ground at high pressure and mixed and stirred with soil to create a ground improvement body. The first embodiment of the present invention is an embodiment of a method for confirming the construction status of construction (high-pressure injection stirring work) using this high-pressure injection stirring method.
As shown in FIG. 1A, the rough procedure of the high-pressure injection agitation method is as follows: First, a ground improvement machine 20 which is a known construction machine for creating an improved ground by the high-pressure injection agitation method is used to advance the ground to be improved. An improved pipe 21 composed of, for example, a triple pipe rod is inserted into the planned drilling point. To insert the improved pipe 21, first, a casing pipe (not shown) having a diameter larger than that of the improved pipe 21 is used to inject drilling water from the tip thereof, rotate the casing pipe to drill a hole, and drill a hole in the casing. Insert the pipe into the ground. Next, the improved pipe 21 is inserted inside the inserted casing pipe, and after the insertion, the casing pipe is pulled out in the example of FIG. 1 (a). As a result, the improved pipe 21 is inserted into the vertical hole 30 drilled by the casing pipe. However, the casing pipe may be left depending on the depth of construction of the ground improvement body and the condition of the ground. When the ground is improved with the casing pipe left, the casing pipe needs to be replaced.

After inserting the improved pipe 21 and pulling out the casing pipe, as shown in FIG. 1 (b), while rotating the improved pipe 21, ultra-high pressure water and compressed air are injected from the injection nozzle 21a to inject the ground. Is cut and the slime S is discharged to the slime pit 32 on the ground. At the same time, a hardening material such as cement milk is injected at high pressure into the voids formed in the ground. At this time, the rotation of the improved pipe 21 causes high-pressure injection of the cured material to the entire circumference of the improved pipe 21 and mixes and stirs the cured material and the cutting ground. In addition, the improved pipe 21 is pulled up at a preset pulling speed for each soil layer constituting the ground portion to be improved. As a result, a substantially cylindrical ground improvement body 31 having the required improvement diameter is created.

Here, the ground portion to be improved is composed of a plurality of types of soil layers having different soil qualities, depths, and the like. Then, the pressure of high-pressure injection, the rotation speed of the improvement pipe 21, and the pulling speed are determined according to the soil quality of each soil layer and the required improvement diameter.
Since the ground improvement body 31 is constructed in the ground, its quality cannot be confirmed from the ground. Therefore, a method of confirming (estimating) whether a ground improvement body satisfying the construction conditions (desired quality) has been constructed (whether the construction is successful) is required.

Next, a method of confirming the construction status of the high-pressure injection agitator and a method of creating a ground improvement body according to the first embodiment will be described.
(1) First, as shown in FIG. 1A, a drilling machine 7 such as a boring machine is used to position the improved pipe 21 inserted in the ground at a position separated by a distance r, which is the required improvement radius in the radial direction. , The observation hole 10 deeper than the insertion depth of the improved pipe 21 is drilled. Then, in the first embodiment, for example, a cylindrical intubation tube 1 made of polyvinyl chloride is built in the observation hole 10.

(2) Next, as shown in FIG. 1 (b), the sensor support 2 is inserted inside the intubation 1.
As shown in FIG. 2, the sensor support 2 includes a long support member 2a that reaches the depth of the tip position (the end on the injection nozzle 21a side) of the improved pipe 21 inserted into the ground from the ground. It has first to third acceleration sensors 3A to 3C fixed to the support member 2a.
The first to third acceleration sensors 3A to 3C are composed of, for example, a strain gauge type acceleration converter that is waterproof and can be used in water or soil. The strain gauge type acceleration converter is a sensor that measures how much acceleration is acting on the object to be measured based on the gravitational acceleration. Further, at the signal output terminals of the first to third acceleration sensors 3A to 3C, one end of an electric cable 4 having a length that can reach the measuring device 5 (described later) on the ground from the depth position at which each is arranged is provided. Each is connected. The other end of the electric cable 4 is connected to the input terminal of the dynamic strain measuring device 50 (described later) of the measuring device 5.

Further, the first to third acceleration sensors 3A to 3C are fixedly arranged at length positions corresponding to the depth positions of the soil layers to be observed on the support member 2a, respectively. That is, when the support member 2a is inserted into the intubation tube 1 and fixed, the first to third acceleration sensors 3A to 3C are fixed at the depth positions of each soil layer to be observed. Each acceleration sensor is fixedly arranged at each corresponding length position of the support member 2a.
Specifically, in the example shown in FIG. 2, the first accelerometer 3A is fixedly arranged at the depth position of the soil layer (silt layer) of cohesive soil in order from the lower layer side, and the second accelerometer 3B is sandy. It is fixedly arranged at the depth position of the soil layer (sandy layer) of the system, and the third acceleration sensor 3C is fixedly arranged at the depth position of the soil layer (buried soil layer) of the buried soil portion. Further, in the first embodiment, the first to third acceleration sensors 3A to 3C are arranged at the central height position in the depth direction of each soil layer.

Then, when the insertion and fixing of the sensor support 2 into the intubation tube 1 is completed, the inside of the intubation tube 1 is filled with a substance capable of transmitting vibration (hereinafter, referred to as “vibration transmitter substance”). In the first embodiment, sand is filled as a vibration transmitter.
Further, in the first embodiment, the support member 2a is composed of, for example, a half-width tubular long member made of aluminum, as shown in FIGS. 3 (a) to 3 (c). The first to third acceleration sensors 3A to 3C (hereinafter, abbreviated as "accelerometer 3" when it is not necessary to distinguish them) are fixedly arranged inside the half-width tubular support member 2a. ..

Specifically, as shown in FIGS. 3A and 3B, the support member 2a is configured by connecting a plurality of half-width tubular members in the longitudinal direction by rivets 2b. Then, as shown in FIGS. 3A and 3C, the acceleration sensor 3 is arranged inside the half-width tubular shape of the support member 2a, and the fastening member (two truss screws 2c in the example of FIG. 3) is used from the outside. Fix it.
More specifically, as shown in FIG. 3D, of the bottom portion 2d forming the half-width tubular shape of the support member 2a and the side walls 2e and 2f rising from both ends thereof, the bottom portion 2d and the side wall 2f are in contact with each other. The acceleration sensor 3 having a substantially cubic shape is arranged as described above. At this time, each acceleration sensor 3 is arranged at a length position corresponding to the depth position of each soil layer of the support member 2a. After that, the acceleration sensor 3 is fixed with two truss screws 2c from the outside of the bottom 2d.

(3) When the insertion and fixing of the sensor support 2 into the intubation 1 and the filling of sand are completed, the ground improvement machine 20 then creates the ground improvement body 31 as shown in FIG. 1 (b). To start. At the same time, the vibrations transmitted through the intubation 1 by the high-pressure injection of the cured material are detected by the first to third acceleration sensors 3A to 3C, and the vibration data as the detection result is obtained by the measuring device 5 shown in FIG. Record by. That is, the vibration transmitted through the soil by the high-pressure injection and the impact due to the collision of the hardening material vibrate the intubation 1, and this vibration is transmitted to the sensor support 2 through the sand filled in the intubation 1, and the acceleration sensor. Detected by 3. Then, the vibration data, which is the vibration data detected by the acceleration sensor 3, is recorded by the measuring device 5.

As shown in FIG. 4, the measuring device 5 includes a dynamic strain measuring device 50, a data recorder 51, a measurement control PC 52, a display device 53, an isolation transformer 54, and an uninterruptible power supply 55. ..
The electric power supplied from the generator 200 is stepped down through the isolation transformer 54 and supplied to the uninterruptible power supply 55. The uninterruptible power supply 55 charges its own secondary battery with the supplied step-down power, and supplies drive power to the data recorder 51, the measurement control PC 52, and the display device 53, respectively. The data recorder 51, the measurement control PC 52, and the display device 53 are driven by the drive power supplied from the uninterruptible power supply 55. Further, in the first embodiment, drive power is supplied to the dynamic strain measuring instrument 50 from the data recorder 51.

Although not shown, the dynamic strain measuring instrument 50 has a receiving unit that individually receives detection signals (strain gauge outputs) input from the first to third acceleration sensors 3A to 3C via the electric cable 4. I have. In addition, it includes an amplifier that amplifies each detection signal received by the receiving unit, and an A / D converter that converts each analog detection signal amplified by the amplifier into a digital signal. Then, each digital detection signal after A / D conversion is output to the data recorder 51 as a vibration signal (vibration data).
The data recorder 51 segregates and sequentially records each vibration data input in time series from the dynamic strain measuring device 50 for each soil layer corresponding to the first to third acceleration sensors 3A to 3C. Hereinafter, the soil layer (silt layer) corresponding to the first acceleration sensor 3A is the lower layer, the soil layer (sandy layer) corresponding to the second acceleration sensor 3B is the middle layer, and the soil layer corresponding to the third acceleration sensor 3C. (Silt layer) is the upper layer.

The measurement control PC 52 is composed of a personal computer, and by executing dedicated measurement software, it is possible to analyze each vibration data for each soil layer recorded by the data recorder 51. For example, the horizontal axis is time and the vertical axis is acceleration (vibration level), and the vibration waveform corresponding to each of the three types of soil layers of the upper layer, the middle layer, and the lower layer is displayed on the display device 53 at an arbitrary magnification. It is possible to cut out a part of the image and enlarge it.

Next, an example of the procedure for ground improvement and the procedure for measuring the vibration generated by the ground improvement will be described.
Here, the present inventors actually carried out a high-pressure injection stirring work for the configuration example of the soil layer shown in FIG. 2, the required improvement diameter (3.5 [m]), and the setting example of the pulling speed of the improvement pipe 21. It will be the same as the one at the time.
In the example shown in FIG. 2, the construction of the ground improvement body 31 is started from the lowest sandy layer (thickness 0.5 [m]), and when the improvement of this sandy layer portion is completed, it is continued in FIG. As shown in (a), the lower silt layer, which is the object of vibration measurement, is improved. The thickness of the silt layer is 1.5 [m] in the example shown in FIG. 2, and the ground improvement is performed at a lifting speed of 12 [minutes / m]. At the central height position in the depth direction of the silt layer, the first acceleration sensor 3A is fixedly arranged in the intubation 1, and the closer the hardened material injected with high pressure is to this central height position, the more the intubation tube 1 is located. The closer it is to 1, the larger the vibration (acceleration) is detected by the first acceleration sensor 3A. The vibration data of the vibration detected by the first acceleration sensor 3A is recorded by the measuring device 5. When the improvement of the silt layer is completed, as shown in FIG. 5A, a first ground improvement body 31a in which the cohesive soil and the hardening material are agitated and mixed is formed.

Subsequently, as shown in FIG. 5B, the sandy layer of the middle layer, which is the measurement target of vibration, is improved. The thickness of the sandy layer is 7.5 [m] in the example shown in FIG. 2, and the ground improvement is performed at a lifting speed of 9 [minutes / m]. A second acceleration sensor 3B is fixedly arranged in the intubation 1 at the central height position in the depth direction of the sandy layer, and the hardened material injected at high pressure approaches the central height position and is outside. The closer to the intubation 1, the larger the vibration detected by the second accelerometer 3B. The vibration data of the vibration detected by the second acceleration sensor 3B is recorded by the measuring device 5. When the improvement of the sandy layer is completed, as shown in FIG. 5B, a second ground improvement body 31b in which the sand and the hardening material are agitated and mixed is formed.

Subsequently, as shown in FIG. 5C, the upper embankment layer, which is the measurement target of vibration, is improved. The thickness of the embankment layer is 2.8 [m] in the example shown in FIG. 2, and the ground improvement is performed at a lifting speed of 9 [minutes / m]. The embankment layer is composed of the same sandy soil as the middle layer. A third acceleration sensor 3C is fixedly arranged in the intubation 1 at the central height position in the depth direction of the filling layer, and the hardened material injected at high pressure approaches the central height position and the intubation is intubated. The closer it is to 1, the larger the vibration is detected by the third acceleration sensor 3C. The vibration data of the vibration detected by the third acceleration sensor 3C is recorded by the measuring device 5. When the improvement of the embankment layer is completed, as shown in FIG. 5C, a third ground improvement body 31c in which sand and the hardening material are agitated and mixed is formed. As a result, the construction of the ground improvement body 31 having a structure in which the first to third ground improvement bodies 31a to 31c are laminated is completed.

(4) When the construction of the ground improvement body 31 is completed and the recording of the vibration data is completed, then, as shown in FIG. 1 (c), the sensor support 2 and the intubation 1 are pulled out by, for example, a boring machine or the like. The work is performed, and the acceleration sensor 3 is collected from the pulled out sensor support 2.

(5) On the other hand, the person in charge of the site who confirms the construction status operates the measurement control PC 52 and confirms the construction status of the high-pressure injection agitator based on the vibration data recorded in the data recorder 51.
Specifically, the person in charge of the site executes the measurement software on the measurement control PC 52 and displays the soil to be measured on the display device 53, for example, as shown in FIGS. 6 (a) to 6 (c). The vibration waveforms based on the vibration data recorded from the start to the end of the ground improvement for each layer are displayed in the order of the upper layer, the middle layer, and the lower layer from the top.
Here, FIGS. 6 (a) to 6 (c) are waveforms of actual measurement data when the high-pressure injection stirring work is actually carried out in the configuration of FIG.

As shown in FIG. 6C, in the lower layer, the vibration of the high-pressure injection is detected by the first acceleration sensor 3A in the range of about 900 [seconds] to 1300 [seconds] from the start of the ground improvement. I understand that. Further, as shown in FIG. 6B, it can be seen that the vibration of the high-pressure injection is detected by the second acceleration sensor 3B in the range of about 5200 [seconds] to 6500 [seconds] in the middle layer. .. Furthermore, as shown in FIG. 6A, in the upper layer, the third acceleration sensor has a range of about 8000 [seconds] to 8400 [seconds] and a range of about 9500 [seconds] to 9800 [seconds]. It can be seen that the vibration of the high pressure injection is detected at 3C.

The blank period between about 3500 [seconds] and 5200 [seconds] in FIG. 6 (b) and the blank period between about 8400 [seconds] and 9500 [seconds] in FIG. 6 (a) are defined. , It will be a period when the ground improvement work is temporarily stopped due to the replacement of the casing pipe.
In addition, the person in charge at the site arranges the upper layer, the middle layer, and the lower layer in this order from the top, as shown in FIGS. 7 (a) to 7 (c), using the measurement software, and FIGS. A part of the vibration waveform shown in c) is cut out and an enlarged waveform whose range is expanded is displayed on the display device 53.

As shown in FIG. 7 (c), the maximum value is "15.985" near 820 [seconds] in the lower layer, and the maximum value is around 5910 [seconds] in the middle layer as shown in FIG. 7 (b). Is "2.411", and as shown in FIG. 7A, it can be seen that in the upper layer, the maximum value is "19.111" near 9620 [seconds]. That is, from these maximum values, the arrival time of the high-pressure injection to the height positions where the first to third acceleration sensors 3A to 3C are arranged can be known.
In this way, the person in charge of the field displays each vibration waveform for analysis on the display device 53, and analyzes each displayed vibration waveform to position the hardened material at the required improved diameter (2r [m]). Check the construction status such as the injection arrival time to the height position (known) of each acceleration sensor. This confirmation result can be reflected in various settings such as the rotation speed and pulling speed of the improvement pipe 21 and the injection pressure of the hardened material when improving the ground having the same configuration, and the creation of a higher quality ground improvement body. It is possible to use it for.

Further, by using the acceleration sensor for the measurement of vibration, it is easy to improve the measurement accuracy as compared with the sound collection by the conventional microphone. For example, the vibration waveforms of FIGS. 7 and 8 are waveforms measured with a sampling period of 30 [Hz], but in the case of an accelerometer, this sampling period should be increased to, for example, 50 [Hz] to improve accuracy. Is easy.
Further details can be obtained by analyzing not only the vibration waveform but also the contents of the chart paper showing the measurement results of the flow meter (not shown) that measures the flow rate of the high-pressure injection pump (not shown) of the hardened material. It is possible to confirm the construction status.

Here, the construction status information measuring device for the high-pressure injection agitator is configured from the external intubation 1, the first to third acceleration sensors 3A to 3C, the vibration transmitting material (sand), and the measuring device 5. ..
Further, the dynamic strain measuring device 50 and the data recorder 51 of the measuring device 5 correspond to the vibration data recording unit.

(Effect of the first embodiment)
The method of confirming the construction status of the high-pressure injection agitator according to the first embodiment is as follows: First, before the construction of the ground improvement body 31, the ground improvement body 31 is located at a position separated by a preset distance r in the radial direction from the construction position. An observation hole 10 having a depth equal to or greater than the construction depth is drilled. Next, an intubation pipe 1 having a length equal to or greater than the creation depth of the ground improvement body 31 is built in the observation hole 10, and the ground portion where the ground improvement body 31 is formed is formed inside the built-in intubation pipe 1. It is transmitted via the intubation 1 to each of the depth positions corresponding to the positions of each of the constituent soil layers (three of the silt layer, the sandy layer, and the embankment layer in the first embodiment). At least one acceleration sensor that detects the vibration to be generated is fixedly arranged. In the first embodiment, a total of three acceleration sensors (first to third acceleration sensors 3A to 3C), one for each layer, are fixedly arranged. After arranging the acceleration sensor 3, the cured material is injected at high pressure from the injection nozzle 21a, and the vibration transmitted through the intubation 1 by this high pressure injection is fixedly arranged at the depth position corresponding to each soil layer. It is detected by the acceleration sensor 3. Then, the vibration data indicating the detection result is recorded (in the first embodiment, it is recorded by the measuring device 5). Furthermore, the construction status of the high-pressure injection agitator is confirmed based on the recorded vibration data.

As a result, each acceleration sensor 3 fixedly arranged at the depth position of each soil layer can individually detect the vibration generated in the intubation 1, and more accurately in each soil layer where the acceleration sensor 3 is arranged. It is possible to check the construction status.
The method for confirming the construction status of the high-pressure injection agitator according to the first embodiment further comprises a long support member 2a having a length equal to or greater than the construction depth of the ground improvement body 31 when the acceleration sensor 3 is arranged. With a plurality of acceleration sensors 3 (first to third acceleration sensors 3A to 3C in the first embodiment) arranged at least one at a length position corresponding to the depth position of each soil layer of the support member 2a. The sensor support 2 having the above is configured. Then, the sensor support 2 is inserted into the intubation tube 1, and after the insertion, the inside of the intubation tube 1 is filled with a substance (sand in the first embodiment) capable of transmitting vibration.
As a result, the vibration can be transmitted to the acceleration sensor 3 without directly contacting the acceleration sensor 3 with the intubation 1, and the degree of freedom in installing the acceleration sensor can be improved.

Further, in the method for creating the ground improvement body according to the first embodiment, the hardened material is injected at high pressure from the injection nozzle 21a of the improvement pipe 21 inserted into the ground, and the improvement pipe 21 is pulled up while rotating to rotate the ground improvement body. The ground improvement body 31 is created by a high-pressure jet stirrer. In addition, the construction status of the high-pressure injection agitator is confirmed by the method for confirming the construction status of the high-pressure injection agitator according to the first embodiment.
As a result, the same effect as the construction status confirmation method of the high-pressure injection agitator can be obtained, and by reflecting the construction status confirmation result in the construction content, it is possible to create a higher quality ground improvement body. Become.

Further, the construction status information measuring device for the high-pressure injection agitation work according to the first embodiment is provided at a position separated by a preset distance r in the radial direction from the construction position of the ground improvement body 31 to improve the ground from the ground surface. The intubation 1 is provided so as to reach below the construction depth of the body 31. Further, at least one fixedly arranged in the intubation 1 at a position corresponding to the depth position of each of the plurality of types of soil layers constituting the ground portion formed by the ground improvement body 31. The first to third acceleration sensors 30A to 30C are provided. Furthermore, a vibration transmitter (sand in the first embodiment) filled in the intubation 1 in which the first to third acceleration sensors 30A to 30C are arranged is provided. Then, the dynamic strain measuring device 50 and the data recorder 51 of the measuring device 5 record the vibration data detected by the first to third acceleration sensors 30A to 30C at the time of constructing the ground improvement body 31 by the high-pressure jet stirring work.
With this configuration, the vibration data of the vibration transmitted via the intubation 1 to the accelerometers arranged at the depth position of each soil layer at the time of construction of the ground improvement body is used as the construction status information of the high-pressure injection stirring method. It becomes possible to measure. This makes it possible to confirm the more accurate construction status in each soil layer where the acceleration sensor is placed based on the measured vibration data.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
In the second embodiment, the cylindrical intubation 1 was built in the observation hole 10 in the first embodiment, whereas the lid portion was provided at the bottom end of the cylindrical intubation 1. The difference is that the second intubation tube 1A of the configuration is built.
Hereinafter, the same components as those in the first embodiment will be designated by the same reference numerals, description thereof will be omitted as appropriate, and only the differences will be described in detail.

As shown in FIGS. 8A and 8B, the second intubation tube 1A has a cross-shaped bit at the bottom end of the cylindrical intubation tube having the same cylindrical shape as the intubation tube 1 of the first embodiment. It has a structure in which 1b is formed. The bit 1b has a hollow portion other than the cross portion, and is connected to the inside of the intubation. By covering the bottom end with the cross-shaped bit 1b in this way, as shown in FIG. 8C, when the second intubation tube 1A is pulled out from the observation hole 10, FIG. As shown in 8 (d), the cross portion of the bit 1b makes it possible to receive the sensor support 2. Further, at the time of drawing out, the sand filled inside can be discharged into the observation hole 10 through the hollow portion of the bit 1b.

(Effect of the second embodiment)
According to the construction status confirmation method of the high-pressure injection agitator according to the second embodiment, as an intubation tube to be built in the observation hole 10, a shape that blocks the passage of the sensor support 2 when the sensor support 2 is pulled out at the bottom end thereof. The second intubation tube 1A in which the lid portion (cross-shaped bit 1b in the second embodiment) was formed was used.
As a result, when the second intubation tube 1A is pulled out, the sensor support 2 can be received by the lid portion, so that the sensor support 2 can be prevented from falling off.
In addition, by providing a hollow portion such as a cross shape of the lid, it is possible to release the vibration transmitter such as sand filled inside through the hollow portion to the outside at the time of pulling out. It is possible to reduce the weight.

(Modification example)
(1) In each of the above embodiments, the inside of the intubation is filled with a vibration transmitter such as sand, but the configuration is not limited to this. For example, as shown in FIG. 9, the sensor support 2 is pressed against the inner peripheral surface of the intubation 1 (or the second intubation 1A) by the leaf spring 2s, and the intubation 1 (or the second intubation 1A) is injected with high pressure of the hardening material. The vibration generated in the second intubation tube 1A) may be directly transmitted to the sensor support 2. At this time, for example, as shown in FIG. 9, the leaf spring 2s is provided so that at least the portion of the sensor support 2 at the arrangement position of the acceleration sensor 3 is in contact with the intubation, and the other portions are provided, for example, as an auxiliary. To do so. With this configuration, it is not necessary to fill the inside of the intubation with a vibration transmitter such as sand, so it is possible to suppress the weight increase at the time of pulling up, and the acceleration sensor and the support member are worn due to the vibration transmitter. Can be suppressed.

(2) In each of the above embodiments, one acceleration sensor is provided for each soil layer to be measured for vibration, but the present invention is not limited to this configuration, and two or more acceleration sensors are provided for each soil layer. May be provided.
(3) In each of the above embodiments, the soil layer to which the acceleration sensor is provided is three types of soil layers, but the configuration is not limited to this configuration, and the configuration is such that the acceleration sensor is provided for two or less types or four or more types of soil layers. May be good.
(4) In each of the above embodiments, one observation hole 10 is drilled at a position separated by a distance r in the radial direction from the improved pipe 21 inserted into the ground to be improved, and vibration is measured. .. Not limited to this configuration, two or more observation holes may be provided around the improved pipe 21 to measure vibration at a plurality of observation hole positions.

(5) In each of the above embodiments, in order to form the ground improvement body, an improved pipe 21 composed of a triple pipe rod is used to inject air and water at high pressure to cut and stir the ground, and then a hardening material (grout) is applied. The configuration uses a triple pipe method for high-pressure injection, but the configuration is not limited to this configuration. For example, the present invention is also applied to other methods such as a single tube method in which only a hardened material is injected at high pressure using a single tube rod, and a double tube method in which a hardened material and air are mixed and injected using a double tube rod. It is possible.
(6) In each of the above embodiments, the inside of the intubation tube 1 after the sensor support 2 is inserted is filled with sand. However, the present invention is not limited to this configuration, and any substance capable of transmitting vibration, such as water, is used. It may be configured to be filled with other substances.

(7) In each of the above embodiments, as an acceleration sensor for measuring vibration, a strain gauge type acceleration converter has been described as an example, but the present invention is not limited to this configuration. For example, other types of acceleration sensors such as a piezoelectric acceleration sensor and a semiconductor acceleration sensor may be adopted.
(8) In each of the above embodiments, after the improved pipe 21 is inserted into the ground, the observation hole 10 is provided at a position separated by a distance r, which is the required improvement radius in the radial direction, from the improved pipe 21 inserted into the ground. It was configured to drill holes. The configuration is not limited to this, and for example, the observation hole 10 may be drilled before the casing pipe is inserted at the drilling point for creating the ground improvement body. Further, even after the improved pipe 21 is inserted, the observation hole 10 may be drilled before the previously inserted casing pipe is pulled out.

(9) In each of the above embodiments, the construction status is confirmed after the recording of the vibration data for all the soil layers to be measured is completed, but the configuration is not limited to this. For example, the configuration may be such that the confirmation work is performed for each soil layer during the recording of the vibration data, such as after the measurement for each soil layer is completed, at other timings.
(10) In each of the above embodiments, the depth of the observation hole 10, the length of the intubation 1 and the length of the sensor support 2 are set to be equal to or greater than the construction depth of the ground improvement body 31. However, it is not limited to this configuration. For example, when measuring vibration only for a specific soil layer above the bottom layer among multiple types of soil layers, the depth and length required to measure the soil layer to be measured. It may be configured as.

1 External tube 1A 2nd external tube 1b Bit 2 Sensor support 2a Support member 2s Leaf spring 3A to 3C 1st to 3rd acceleration sensors 4 Electric cable 5 Measuring device 7 Drilling machine 10 Observation hole 20 Ground improvement machine 21 Improved tube 21a Injection nozzle 31 Ground improved body 31a to 31c First to third ground improved body 50 Dynamic strain measuring instrument 51 Data recorder 52 Measurement control PC
53 Display device

Claims (4)

Check the construction status of the high-pressure injection agitator that creates a ground improvement body by injecting the hardening material at high pressure from the injection nozzle of the improved pipe inserted in the ground and pulling up the improved pipe while rotating it. It is a construction status confirmation method,
An observation hole drilling step of drilling an observation hole at a position separated by a preset distance in the radial direction from the construction position before the construction of the ground improvement body.
The process of building an intubation tube in the observation hole, and the process of building an intubation tube,
It is transmitted via the intubation to each of the depth positions corresponding to the positions of the soil layers of the plurality of types of soil layers constituting the ground portion formed by the ground improvement body inside the intubation. A sensor placement process in which at least one acceleration sensor that detects vibration is fixedly placed,
After the sensor placement step, the hardened material is injected at high pressure from the injection nozzle, and the vibration transmitted through the intubation by this high pressure injection is fixedly arranged at the depth position corresponding to each soil layer. A vibration recording step of detecting with the acceleration sensor and recording vibration data indicating the detection result,
See containing and a construction condition confirmation step of confirming construction status of the high-pressure injection stirring Engineering based on the recorded the vibration data was by the vibration recording step,
The observation hole has a depth equal to or greater than the formation depth of the ground improvement body, and the intubation has a length equal to or greater than the formation depth of the ground improvement body.
In the sensor placement step, at least one long support member having a length equal to or greater than the construction depth of the ground improvement body and one at a length position corresponding to the depth position of each soil layer of the support member. A sensor support having a plurality of the acceleration sensors arranged one by one is inserted into the external tube, and after the insertion, the inside of the external tube is filled with a vibration transmitting substance which is a substance capable of transmitting vibration. How to check the construction status of the work. Check the construction status of the high-pressure injection agitator that creates a ground improvement body by injecting the hardening material at high pressure from the injection nozzle of the improved pipe inserted in the ground and pulling up the improved pipe while rotating it. It is a construction status confirmation method,
An observation hole drilling step of drilling an observation hole at a position separated by a preset distance in the radial direction from the construction position before the construction of the ground improvement body.
The process of building an intubation tube in the observation hole, and the process of building an intubation tube,
It is transmitted via the intubation to each of the depth positions corresponding to the positions of the soil layers of the plurality of types of soil layers constituting the ground portion formed by the ground improvement body inside the intubation. A sensor placement process in which at least one acceleration sensor that detects vibration is fixedly placed,
After the sensor placement step, the hardened material is injected at high pressure from the injection nozzle, and the vibration transmitted through the intubation by this high pressure injection is fixedly arranged at the depth position corresponding to each soil layer. A vibration recording step of detecting with the acceleration sensor and recording vibration data indicating the detection result,
Including a construction status confirmation step of confirming the construction status of the high-pressure injection agitator based on the vibration data recorded by the vibration recording step.
The observation hole has a depth equal to or greater than the formation depth of the ground improvement body, and the intubation has a length equal to or greater than the formation depth of the ground improvement body.
In the sensor placement step, at least one long support member having a length equal to or greater than the construction depth of the ground improvement body and one at a length position corresponding to the depth position of each soil layer of the support member. A high-pressure injection stirrer in which a sensor support having a plurality of the acceleration sensors arranged one by one is installed in the external intubation so that the sensor support is fixedly arranged in a state of being in contact with the inner surface of the intubation. Construction status confirmation method. In the sensor arranging step, claim 1 or 2 uses the intubation having a lid formed at the bottom end to prevent the sensor support from passing through when the intubation is pulled out. The method for confirming the construction status of the high-pressure injection agitator described. A ground improvement body that creates the ground improvement body by a high-pressure injection stirrer that creates a ground improvement body by injecting a hardened material at high pressure from the injection nozzle of the improvement pipe inserted into the ground and pulling up the improvement pipe while rotating it. The construction process and
A ground improvement body comprising a construction status confirmation step of confirming the construction status of the high pressure injection agitator by the construction status confirmation method of the high pressure injection agitator according to any one of claims 1 to 3. How to create.

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