JP2018131735A - Construction status confirmation method for high pressure jet agitation work, method for creating soil improvement body using the same, and construction status information measuring device for high pressure jet agitation work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction status confirmation method for high pressure jet agitation work allowing confirmation of accurate construction status at a specific height position of each soil layer constituting the ground portion creating a soil improvement body.SOLUTION: An observation hole 10 is drilled at a position separated from a creating position of a soil improvement body by a distance of r in the radial direction, and a cylindrical external insertion pipe 1 is erected in the observation hole 10. Furthermore, an acceleration sensor is fixedly arranged to each of the depth positions corresponding to the position of respective soil layers of multiple kinds of soil layers constituting the soil parts to be improved. Then, a hardener is injected at a high pressure from an injection nozzle 21a of an improvement pipe 21, vibration caused by the high pressure injection and transmitted via the external insertion pipe 1 is detected by first to third acceleration sensors 3A-3C fixedly arranged at the depth positions corresponding to the respective soil layers, and vibration data showing the detection results are recorded in a measuring device 5. The construction status of the high pressure jet agitation work is confirmed on the basis of the recorded vibration data.SELECTED DRAWING: Figure 1

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 jet agitator, for example, there is a technique disclosed in Patent Document 1. In this technology, a plurality of vertical holes are formed at different positions around the injection pipe inserted into the ground at different distances from the injection pipe, a built-in pipe is inserted into the vertical hole, and a sealing material is provided around the vertical pipe. The erection pipe is fixed by filling. Thereafter, a detector for detecting the vibration generated by the built-in pipe is suspended in the built-in pipe, and then the curing material is injected at a high pressure from the injection nozzle of the injection pipe, and the vibration at that time is detected by the detector. And the cutting state of the ground is confirmed by monitoring this detection result. In this technique, a sound collecting microphone is used as a detector. In addition, by pulling up the sound collecting microphone with the lifting device in synchronization with the pulling speed of the injection pipe, the sound collecting microphone is moved following the injection position of the hardened material, and the sound that the hardened material hits the built-in pipe is more The sound can be monitored clearly with a microphone.

JP 2012-62626 A

However, in the method disclosed in Patent Document 1, since the sound collection microphone moves and its height position changes, it is difficult to grasp the accurate arrival position of the injection nozzle in the height direction. For this reason, it is difficult to grasp the construction status such as the pulling speed (actual speed) of the injection tube that requires accurate arrival height position information of the injection nozzle.
In addition, since a common sound collection microphone is used for multiple soil layers with different soil properties and the sound that the hardener hits the built-in pipe while being moved, the cause of the change in the collected sound is the soil. It becomes difficult to grasp the construction status of each soil layer, such as whether it is straddling the layer or other causes (radial injection failure, etc.).

  Therefore, the present invention has been made paying attention to such an unsolved problem of the prior art, and is accurate to the specific height position of each soil layer that constitutes the ground portion that forms the ground improvement body. To provide a construction status confirmation method for a high-pressure jet agitator capable of confirming the correct construction status, a method for creating a ground improvement body using this method, and a construction status information measuring device for a high-pressure jet agitator Yes.

  In order to achieve the above object, a method for confirming the construction status of a high-pressure jet agitator according to the first aspect of the present invention is a method of high-pressure jetting a hardener from a jet nozzle of an improved pipe inserted into the ground and the improved pipe. This is a method for confirming the construction status of a high-pressure jet agitator that creates a ground improvement body by pulling it up while rotating it, and in the radial direction from its creation position before creating the ground improvement body An observation hole drilling step for drilling an observation hole at a position separated by a preset distance, an extrapolation tube erection step for constructing an extratubation tube in the observation hole, and the inside of the extrapolation tube, At least an acceleration sensor for detecting vibrations transmitted through the extrapolation tube at 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 on which the ground improvement body is formed Fix one by one A placement position of the sensor, and a depth position corresponding to each of the soil layers, wherein the hardened material is sprayed from the spray nozzle at a high pressure after the sensor placement process, and the vibration transmitted through the outer cannula by the high pressure spray A vibration recording step for detecting vibration data that is detected by each of the acceleration sensors that are fixedly disposed on the recording medium, and recording vibration data indicating the detection results, and a construction status of the high-pressure jet agitator based on the vibration data recorded by the vibration recording step. And a construction status confirmation process for confirming.

  In order to achieve the above object, the ground improvement body according to the second aspect of the present invention includes a method for forming a ground improvement body by high-pressure injection of a hardened material from an injection nozzle of an improvement pipe inserted into the ground. The high pressure injection stirrer for forming the ground improvement body by a high pressure jet agitator for generating a ground improvement body by pulling up while rotating, and the high pressure injection stirrer construction status confirmation method according to the first aspect described above. A construction status confirmation step for confirming the construction status of the jet agitator.

  In order to achieve the above object, the construction status information measuring device for high-pressure jet agitator according to the third aspect of the present invention is a ground improvement body construction work for creating a ground improvement body by a high-pressure jet agitation method. A construction status information measuring device for high-pressure agitators that measures construction status information related to the construction status of the high-pressure jet agitator, and is provided at a position that is separated from the formation position of the ground improvement body by a predetermined distance in the radial direction. In addition, the outer intubation reaching from the ground surface to below the formation depth of the ground improvement body, and the depth of each soil layer of a plurality of types of soil layers that constitute the ground portion in the outer insertion pipe where the ground improvement body is created An acceleration sensor fixedly disposed at least one position corresponding to the position, a vibration transmitting substance that is a substance capable of transmitting vibrations filled in the outer tube where the acceleration sensor is disposed, and the high-pressure jet agitator In I and a vibration data recording unit for recording the vibration data detected by the acceleration sensor during reclamation the soil improvement material.

  According to the present invention, at least one acceleration sensor is fixedly arranged at each depth position corresponding to the position of each soil layer constituting the ground portion for forming the ground improvement body in the observation hole, and these fixed positions are arranged. Each acceleration sensor individually detects vibrations generated in the extratubation at each soil layer position. As a result, it is possible to measure vibration data of vibration transmitted through an extrapolation tube to an acceleration sensor arranged at the depth position of each soil layer when constructing a ground improvement body as construction status information of the high-pressure jet agitation method. It becomes possible. In addition, it becomes possible to confirm a more accurate construction status in each soil layer where the acceleration sensor is arranged based on the measured vibration data. Moreover, it becomes possible to create a higher quality ground improvement body by reflecting this confirmation result on the construction content.

(A)-(c) is a figure which shows an example of the flow of the construction status confirmation method of the high-pressure jet agitator which concerns on 1st Embodiment, and the construction method of a ground improvement body, and is the figure which transparently displayed the extratubation pipe | tube. . It is a figure which shows an example of the structure of the soil layer of a ground improvement part, the pulling-up speed of an improvement pipe | tube, a required improvement diameter, and the arrangement position of an acceleration sensor. (A)-(d) is a figure for demonstrating the structure of a sensor support body, and the attachment structure of an acceleration sensor, (a) is the figure which looked at a part of sensor support body 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) as viewed from the side surface and the back surface side, and (d) is It is AA sectional view taken on the line of (a). It is a block diagram which shows the specific structure of the measuring apparatus which concerns on 1st Embodiment. (A)-(c) is a figure which shows an example of the formation procedure of a ground improvement body. (A)-(c) is a wave form diagram which shows an example of the vibration waveform of the vibration detected with the 1st-3rd acceleration sensor. (A)-(c) is the figure which clipped and enlarged and displayed a part of each vibration waveform of FIG. (A)-(b) is a figure which shows the structural example of the 2nd extrapolation tube which concerns on 2nd Embodiment, (c)-(d) is a figure for demonstrating the effect at the time of extraction. . It is a figure which shows an example of the installation structure of the sensor support body which concerns on a modification.

Next, first to second embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and vertical and horizontal dimensions and scales of members or portions may be different from actual ones. Therefore, specific dimensions and scales should be determined in consideration of the following description. Of course, the drawings may include portions having different dimensional relationships and ratios.
In addition, the first to second embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material of components, The shape, structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

(First embodiment)
The high-pressure jet agitation method is one of ground improvement body construction methods in which a liquid hardening material is jetted at high pressure in the ground and mixed with agitation to create a ground improvement body. 1st Embodiment of this invention is one Embodiment of the method of confirming the construction condition of the construction (high pressure injection agitator) using this high pressure injection agitator method.
As shown in FIG. 1 (a), the rough procedure of the high-pressure jet agitation is first performed in advance on the ground to be improved by the ground improvement machine 20 which is a well-known construction machine for creating an improved ground by the high-pressure injection agitation method. An improved tube 21 made of, for example, a triple tube rod is inserted into the planned drilling point. The improved pipe 21 is inserted by first rotating a casing pipe with a casing pipe (not shown) having a diameter larger than that of the improved pipe 21 while rotating the casing pipe to cut a drilling point, and then casing the casing. Insert the tube into the ground. Next, the improvement pipe | tube 21 is inserted inside the inserted casing pipe | tube, and after insertion, a casing pipe | tube is pulled out in the example of Fig.1 (a). Thereby, the improved pipe 21 is inserted into the vertical hole 30 drilled by the casing pipe. However, the casing tube may be left depending on the depth of the ground improvement body and the ground condition. When ground improvement is performed with the casing pipe remaining, a replacement work for the casing pipe occurs.

  After the improved pipe 21 is inserted and the casing pipe is pulled out, as shown in FIG. 1 (b), the high pressure water and compressed air are jetted from the jet nozzle 21a while rotating the improved pipe 21, and the ground And the slime S is discharged into the slime pit 32 on the ground. At the same time, a hardener such as cement milk is sprayed at a high pressure into the gap formed in the ground. At this time, the improved pipe 21 rotates, whereby the high-pressure injection of the hardened material is performed on the entire periphery of the improved pipe 21 and the hardened material and the cutting ground are mixed and stirred. In addition, the improvement pipe | tube 21 is pulled up with the raising speed preset for every soil layer which comprises the ground part of improvement object. Thereby, the substantially cylindrical ground improvement body 31 which has a 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 properties and depths. And according to the soil quality and required improvement diameter of each soil layer, the pressure of high-pressure injection, the rotation speed of the improvement pipe 21, and the pulling-up speed are determined respectively.
Since the ground improvement body 31 is built in the ground, it cannot be confirmed whether it is good or bad from the ground. Therefore, a method for confirming (estimating) whether or not a ground improvement body that satisfies the creation condition (desired quality) has been created (whether the construction is successful) is required.

Next, a construction status confirmation method and a ground improvement body construction method for the high-pressure jet agitator according to the first embodiment will be described.
(1) First, as shown in FIG. 1 (a), a drilling machine 7 such as a boring machine is separated from the improved pipe 21 inserted in the ground by a distance r that is a required improved radius in the radial direction. The observation hole 10 deeper than the insertion depth of the improved tube 21 is drilled. In the first embodiment, for example, a cylindrical outer tube 1 made of polyvinyl chloride is installed in the observation hole 10.

(2) Next, as shown in FIG. 1 (b), the sensor support 2 is inserted into the outer tube 1.
As shown in FIG. 2, the sensor support 2 includes a long support member 2a that reaches from the ground to the depth of the tip of the improved tube 21 inserted into the ground (the end on the injection nozzle 21a side), It has 1st-3rd acceleration sensors 3A-3C fixed to the support member 2a.
The first to third acceleration sensors 3 </ b> A to 3 </ b> C are constructed of, for example, strain gauge type acceleration transducers that are waterproof and can be used in water or in 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 gravitational acceleration. In addition, the signal output terminals of the first to third acceleration sensors 3 </ b> A to 3 </ b> C have one end of an electric cable 4 having a length that can reach a measuring device 5 (described later) on the ground from the depth position at which each of the first to third acceleration sensors 3 </ b> A to 3 </ b> C is disposed. Each is connected. The other end of the electric cable 4 is connected to an input terminal of a dynamic strain measuring instrument 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 respective soil layers to be observed in the support member 2a. That is, when the support member 2a is inserted into the outer tube 1 and fixed, the first to third acceleration sensors 3A to 3C are fixed to the depth positions of the respective soil layers 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, in order from the lower layer side, the first acceleration sensor 3A is fixedly disposed at the depth position of the soil layer (silt layer) of the clay soil, and the second acceleration sensor 3B is sandy. The third acceleration sensor 3C is fixedly arranged at the depth position of the soil layer (buried layer) of the buried soil portion. In the first embodiment, the first to third acceleration sensors 3A to 3C are arranged at the center height position in the depth direction of each soil layer.

When the insertion and fixation of the sensor support 2 into the outer tube 1 is completed, the outer tube 1 is filled with a substance capable of transmitting vibration (hereinafter referred to as “vibration transmitting substance”). In the first embodiment, sand is filled as a vibration transmitting substance.
In the first embodiment, the support member 2a is composed of, for example, a half-tubular long member made of aluminum, for example, as shown in FIGS. The first to third acceleration sensors 3A to 3C (hereinafter, abbreviated as “acceleration sensor 3” when there is no need to distinguish them) are fixedly arranged inside the half-square cylindrical support member 2a. .

Specifically, as shown in FIGS. 3 (a) and 3 (b), the support member 2a is formed by connecting a plurality of half-square cylindrical 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-angle cylindrical shape of the support member 2a, and is fastened by a fastening member (in the example of FIG. 3, two truss screws 2c) from the outside. Fix it.
More specifically, as shown in FIG. 3 (d), the bottom 2d of the support member 2a and the side walls 2e and 2f rising from both ends of the bottom 2d are in contact with the bottom 2d and the side wall 2f. Thus, the substantially cubic acceleration sensor 3 is arranged. 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. Thereafter, the acceleration sensor 3 is fixed by two truss screws 2c from the outside of the bottom 2d.

(3) When the insertion and fixing of the sensor support body 2 into the extratubation tube 1 and the filling of the sand are completed, the ground improvement body 31 is then created by the ground improvement machine 20, as shown in FIG. To start. At the same time, vibrations transmitted through the outer tube 1 by high-pressure injection of the hardened material are detected by the first to third acceleration sensors 3A to 3C, and the vibration data as the detection results are detected by the measuring device 5 shown in FIG. Record by. That is, the vibration transmitted through the soil by the high-pressure jet and the impact caused by the collision of the hardened material vibrate the outer tube 1, and this vibration is transmitted to the sensor support 2 through the sand filled in the outer tube 1, and the acceleration sensor 3 is detected. Vibration data that is 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 instrument 50, a data recorder 51, a measurement control PC 52, a display device 53, an insulating transformer 54, and an uninterruptible power supply 55. .
The electric power supplied from the generator 200 is stepped down through the insulating transformer 54 and supplied to the uninterruptible power supply 55. The uninterruptible power supply 55 charges the secondary battery included in the uninterruptible power supply with the supplied step-down power, and supplies driving 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 driving power supplied from the uninterruptible power supply 55. In the first embodiment, the dynamic strain measuring instrument 50 is supplied with driving power from the data recorder 51.

Although not shown, the dynamic strain measuring instrument 50 includes a receiving unit that individually receives detection signals (outputs of strain gauges) input from the first to third acceleration sensors 3A to 3C via the electric cable 4, respectively. I have. In addition, 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 are provided. 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 classifies and sequentially records each vibration data input from the dynamic strain measuring instrument 50 for each soil layer corresponding to each of 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. (Fill layer) is the upper layer.

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

Next, an example of a procedure for ground improvement and a measurement procedure for vibration generated by the ground improvement will be described.
Here, in the configuration example of the soil layer shown in FIG. 2, the setting example of the required improved diameter (3.5 [m]) and the lifting speed of the improved pipe 21, the present inventors actually carried out high-pressure jet agitation. It will be the same as the time.
In the example shown in FIG. 2, the ground improvement body 31 is started from the bottom sandy layer (thickness 0.5 [m]). When the improvement of the sandy layer portion is completed, FIG. As shown to (a), the improvement of the lower silt layer which is a measuring object of a vibration is performed. In the example shown in FIG. 2, the thickness of the silt layer is 1.5 [m], and the ground improvement is performed at a lifting speed of 12 [min / m]. The first acceleration sensor 3A is fixedly disposed in the outer cannula 1 at the center height position in the depth direction of the silt layer. The closer the value is to 1, the greater the vibration (acceleration) detected by the first acceleration sensor 3A. 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 viscous soil and the hardener are mixed with stirring is created.

  Subsequently, as shown in FIG. 5 (b), the sandy layer of the middle layer that is the object of vibration measurement is improved. In the example shown in FIG. 2, the thickness of the sandy layer is 7.5 [m], and the ground improvement is performed at a lifting speed of 9 [min / m]. The second acceleration sensor 3B is fixedly arranged in the outer cannula 1 at the center height position in the depth direction of the sandy layer, and the hardened material injected with high pressure approaches the center height position and the outside is increased. The closer to the intubation 1, the greater the vibration is detected by the second acceleration sensor 3B. 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. 5 (b), the second ground improvement body 31b in which the sand and the hardener are stirred and mixed is created.

  Then, as shown in FIG.5 (c), the upper embankment layer which is a measuring object of a vibration is improved. In the example shown in FIG. 2, the thickness of the embankment layer is 2.8 [m], and the ground improvement is performed at a lifting speed of 9 [min / m]. The embankment layer is composed of the same sandy soil as the middle layer. The third acceleration sensor 3C is fixedly disposed in the outer cannula 1 at the center height position in the depth direction of the embankment layer, and the outer cannula is so close that the hardened material injected with high pressure approaches the center height position. The closer the value is to 1, the greater the vibration detected by the third acceleration sensor 3C. 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. 5 (c), a third ground improvement body 31c in which sand and a hardener are stirred and mixed is created. Thereby, creation of the ground improvement body 31 of the structure by which the 1st-3rd ground improvement bodies 31a-31c were laminated | stacked is completed.

(4) When the formation of the ground improvement body 31 is completed and the recording of the vibration data is completed, then, as shown in FIG. 1 (c), for example, the sensor support 2 and the extratubation tube 1 are pulled out by a boring machine or the like. Work is performed and the acceleration sensor 3 is recovered from the sensor support 2 that has been pulled out.

(5) On the other hand, the person in charge confirming the construction status operates the measurement control PC 52 and confirms the construction status of the high-pressure jet 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 measurement target soil 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 order from the top to the upper layer, the middle layer, and the lower layer.
Here, FIG. 6A to FIG. 6C are waveforms of actually measured data when the high-pressure jet stirring work is actually performed with 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 ground improvement. I understand that. Moreover, as shown in FIG.6 (b), in the middle layer, it turns out that the vibration of a high pressure injection is detected by the 2nd acceleration sensor 3B in the range of about 5200 [second]-6500 [second]. . 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.

Note that the blank period between about 3500 [seconds] to 5200 [seconds] in FIG. 6B and the blank period between about 8400 [seconds] to 9500 [seconds] in FIG. The ground improvement work is temporarily stopped by the replacement of the casing tube.
Moreover, the person in charge of the site arranges the upper layer, the middle layer, and the lower layer in order from the top, as shown in FIGS. 7A to 7C, for example, with the measurement software. An enlarged waveform obtained by cutting out a part of the vibration waveform shown in c) and expanding the range is displayed on the display device 53.

As shown in FIG. 7C, the maximum value is “15.985” in the vicinity of 820 [seconds] in the lower layer, and the maximum value is in the vicinity of 5910 [seconds] in the middle layer as shown in FIG. 7B. Becomes “2.411”, and as shown in FIG. 7A, in the upper layer, it is understood that the maximum value is “19.111” in the vicinity of 9620 [seconds]. That is, the arrival time of the high pressure injection to the height position where the first to third acceleration sensors 3A to 3C are arranged can be determined from these maximum values.
Thus, the person in charge on the site displays each vibration waveform for analysis on the display device 53, and analyzes each displayed vibration waveform, so that the position of the hardened material at the necessary improved diameter (2r [m]) is obtained. Whether or not it has reached, the construction status such as the injection arrival time to the height position (known) of each acceleration sensor is confirmed. 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 of the same configuration, and the creation of a higher quality ground improvement body. It is possible to help.

In addition, by using an acceleration sensor for vibration measurement, it is easy to increase the measurement accuracy as compared with sound collection by a conventional microphone. For example, the vibration waveforms in FIG. 7 and FIG. 8 are waveforms measured at a sampling period of 30 [Hz]. For an acceleration sensor, the sampling period is increased to, for example, 50 [Hz] for higher accuracy. Is easy.
Moreover, not only the vibration waveform but also the details of the chart paper showing the measurement result of the flow meter (not shown) that measures the flow rate of the high-pressure injection pump (not shown) of the hardened material are also analyzed in detail. It is possible to confirm the correct construction status.

Here, the extrapolation tube 1, the first to third acceleration sensors 3A to 3C, the vibration transmitting substance (sand) and the measuring device 5 constitute a construction status information measuring device for high-pressure jet agitator. .
The dynamic strain measuring instrument 50 and the data recorder 51 of the measuring device 5 correspond to a vibration data recording unit.

(Effect of 1st Embodiment)
In the construction status confirmation method of the high-pressure jet agitator according to the first embodiment, first, before the ground improvement body 31 is formed, the ground improvement body 31 is located at a position separated by a predetermined distance r in the radial direction from the formation position. The observation hole 10 having a depth greater than the formation depth is drilled. Next, in the observation hole 10, the extrapolation tube 1 having a length equal to or longer than the formation depth of the ground improvement body 31 is built, and the ground portion where the ground improvement body 31 is created inside the built-in extrapolation tube 1 Transmission through the extrapolation tube 1 to each of the depth positions corresponding to the positions of each of the multiple types of soil layers (in the first embodiment, three layers of silt layer, sandy layer, and embankment layer). At least one acceleration sensor for detecting the vibration to be detected 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 the arrangement of the acceleration sensor 3, the hardened material is injected at a high pressure from the injection nozzle 21a, and the vibration transmitted through the outer insertion tube 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, vibration data indicating the detection result is recorded (in the first embodiment, recorded by the measuring device 5). Furthermore, the construction status of the high-pressure jet agitator is confirmed based on the recorded vibration data.

Accordingly, it is possible to individually detect vibration generated in the outer cannula 1 by each acceleration sensor 3 fixedly arranged at the depth position of each soil layer, and more accurately in each soil layer where the acceleration sensor 3 is disposed. It is possible to confirm the correct construction status.
In the construction status confirmation method for the high-pressure jet agitator according to the first embodiment, when the acceleration sensor 3 is further disposed, the long support member 2a having a length equal to or longer than the formation depth of the ground improvement body 31 and the A plurality of acceleration sensors 3 (first to third acceleration sensors 3A to 3C in the first embodiment) arranged at least one each at a length position corresponding to the depth position of each soil layer of the support member 2a; The sensor support body 2 which has these is comprised. Then, the sensor support 2 is inserted into the outer tube 1 and, after the insertion, the inside of the outer tube 1 is filled with a substance capable of transmitting vibration (sand in the first embodiment).
This makes it possible to transmit vibration to the acceleration sensor 3 without bringing the acceleration sensor 3 into direct contact with the outer cannula 1 and to improve the degree of freedom of installation of the acceleration sensor.

Moreover, the ground improvement body creation method according to the first embodiment is that the ground improvement body is formed by high-pressure injection of the hardened material from the injection nozzle 21a of the improvement pipe 21 inserted in the ground and pulling up the improvement pipe 21 while rotating it. The ground improvement body 31 is formed by the high-pressure jet agitating process. In addition, the construction status of the high-pressure jet agitator is confirmed by the construction status confirmation method for the high-pressure jet agitator according to the first embodiment.
As a result, the same effect as the construction status confirmation method of the high-pressure jet agitator can be obtained, and it is possible to create a higher quality ground improvement body by reflecting the construction status confirmation result in the construction content. Become.

In addition, the construction status information measuring device for high-pressure jet agitator according to the first embodiment is provided with a ground improvement from the ground surface, which is provided at a position separated by a predetermined distance r in the radial direction from the formation position of the ground improvement body 31. An extratubation tube 1 that extends below the formation depth of the body 31 is provided. Furthermore, in the extrapolation tube 1, at least one is fixedly arranged at a position corresponding to the depth position of each soil layer of a plurality of types of soil layers constituting the ground portion on which the ground improvement body 31 is formed. 1st-3rd acceleration sensors 30A-30C are provided. Still further, a vibration transmitting material (sand in the first embodiment) filled in the outer intubation tube 1 in which the first to third acceleration sensors 30A to 30C are arranged is provided. And the dynamic strain measuring device 50 of the measuring apparatus 5 and the data recorder 51 record the vibration data detected by the 1st-3rd acceleration sensors 30A-30C at the time of constructing the ground improvement body 31 by a high-pressure jet agitator.
If it is this structure, the vibration data of the vibration transmitted through the extrapolation pipe 1 to the acceleration sensor arrange | positioned at the depth position of each soil layer at the time of construction of a ground improvement body as construction status information of a high-pressure jet stirring method It becomes possible to measure. Thereby, it becomes possible to confirm a more accurate construction situation in each soil layer in which the acceleration sensor is arranged 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 extrapolation tube 1 is built in the observation hole 10 in the first embodiment, but a lid is provided at the end on the bottom side of the cylindrical extrapolation tube 1. The difference is that a second extratubation tube 1A having a configuration is built.
Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted as appropriate, and only different points will be described in detail.

  As shown in FIGS. 8 (a) and 8 (b), the second extrapolation tube 1A has a cross-shaped bit at the end on the bottom side of the same cylindrical extrapolation tube as the extrapolation tube 1 of the first embodiment. 1b is formed. The bit 1b has a hollow portion other than the cross portion and communicates with the inside of the extratubation tube. Since the bottom end is thus covered with the cross-shaped bit 1b, as shown in FIG. 8C, when the second extrapolation tube 1A is pulled out from the observation hole 10, As shown in FIG. 8D, the sensor support 2 can be received by the cross portion of the bit 1b. In addition, at the time of drawing, the sand filled inside can be discharged into the observation hole 10 through the hollow portion of the bit 1b.

(Effect of 2nd Embodiment)
According to the construction status confirmation method of the high-pressure jet agitator according to the second embodiment, as an extrapolated tube to be built in the observation hole 10, a shape that obstructs the passage of the sensor support 2 when it is pulled out at the end on the bottom side. The second extratubation tube 1A in which the lid portion (the cross-shaped bit 1b in the second embodiment) is formed is used.
As a result, when the second extrapolation tube 1A is pulled out, the sensor support 2 can be received by the lid, so that the sensor support 2 can be prevented from falling off.
In addition, by providing a hollow part such as a cross shape of the lid, it is possible to release vibration transmitting substances such as sand filled inside through the hollow part when pulling out. The weight can be reduced.

(Modification)
(1) In each of the above embodiments, the inside of the extratubation tube is filled with a vibration transmitting substance such as sand. However, the present invention is not limited to this configuration. For example, as shown in FIG. 9, the sensor support 2 is pressed against the inner peripheral surface of the outer tube 1 (or the second outer tube 1 </ b> A) by the leaf spring 2 s, and the outer tube 1 (or the high pressure injection of the curing material). The vibration generated in the second extrapolation tube 1 </ b> A) 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 where the acceleration sensor 3 is arranged on the sensor support 2 is in contact with the outer insertion tube, and the other portions are provided, for example, in an auxiliary manner. Like that. With this configuration, it is not necessary to fill the extratubation tube with a vibration transmitting material such as sand, so that it is possible to suppress an increase in weight during pulling up and wear of the acceleration sensor and the support member due to the vibration transmitting material. Can be suppressed.

(2) In each of the above embodiments, one acceleration sensor is provided for each soil layer to be measured for vibration. However, the present invention is not limited to this configuration, and two or more acceleration sensors are provided for each soil layer. It is good also as a structure which provides.
(3) In each of the above embodiments, the soil layer in which the acceleration sensor is provided is three types of soil layers. However, the present invention is not limited to this configuration, and the acceleration sensor is provided in two or less types or four or more types of soil layers. Also good.
(4) In each of the above-described embodiments, the vibration is measured by drilling one observation hole 10 at a distance r in the radial direction from the improved pipe 21 inserted in the ground to be improved. . Not limited to this configuration, two or more observation holes may be provided around the improved tube 21 and vibration may be measured at a plurality of observation hole positions.

(5) In each of the above-described embodiments, the ground improvement body is formed by using the improvement pipe 21 composed of a triple pipe rod to inject air and water at a high pressure to cut and agitate the ground, and then the hardened material (grout). Although the triple-pipe system that performs high-pressure injection is used, the configuration is not limited to this. For example, the present invention is applied to other methods such as a single tube method in which only a hardened material is injected at a 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. Is possible.
(6) In each of the above embodiments, the inside of the outer tube 1 after the sensor support 2 is inserted is filled with sand. However, the present invention is not limited to this configuration. It is good also as a structure filled with other substances.

(7) In each of the above embodiments, a strain gauge type acceleration transducer has been described as an example of an acceleration sensor for measuring vibration, but the present invention is not limited to this configuration. For example, another type of acceleration sensor such as a piezoelectric acceleration sensor or a semiconductor acceleration sensor may be employed.
(8) In each of the embodiments described above, after the improved tube 21 is inserted into the ground, the observation hole 10 is placed at a position separated from the improved tube 21 inserted into the ground by a distance r that is a required modified radius in the radial direction. It was set as the structure which drills. For example, the observation hole 10 may be drilled before inserting the casing pipe into the drilling point for creating the ground improvement body. Further, even after the improved tube 21 is inserted, the observation hole 10 may be drilled before the previously inserted casing tube is pulled out.

(9) In each of the above embodiments, the construction status is confirmed after the recording of vibration data for all soil layers to be measured is completed. However, the present invention is not limited to this configuration. For example, a configuration may be adopted in which confirmation work is performed for each soil layer during recording of vibration data, for example, after completion of measurement for each soil layer, at other timings.
(10) In each of the above embodiments, the depth of the observation hole 10, the length of the extratubation tube 1, and the length of the sensor support 2 are set to a depth and length that are equal to or greater than the formation depth of the ground improvement body 31. However, the configuration is not limited to this. For example, when vibration is measured only for a specific soil layer above the lowest layer among multiple types of soil layers, the depth and length required to measure the soil layer to be measured You may comprise.

DESCRIPTION OF SYMBOLS 1 1 extrapolation tube 1A 2nd extrapolation tube 1b bit 2 sensor support body 2a support member 2s leaf spring 3A-3C 1st-3rd acceleration sensor 4 electric cable 5 measuring device 7 drilling machine 10 observation hole 20 ground improvement machine 21 Improved pipe 21a Injection nozzle 31 Ground improvement bodies 31a to 31c First to third ground improvement bodies 50 Dynamic strain measuring device 51 Data recorder 52 PC for measurement control
53 Display device

Claims (7)

The high pressure jet agitator confirms the construction status of the high pressure jet agitator that builds the ground improvement body by injecting the hardened material at a high pressure from the injection nozzle of the improved pipe inserted into the ground and pulling up the improved pipe while rotating. It is a construction status confirmation method,
An observation hole drilling step for drilling an observation hole at a position separated by a predetermined distance in the radial direction from the formation position before the formation of the ground improvement body;
In the observation hole, an extratubation tube installation step of installing an extratubation tube,
It is transmitted via the extrapolation tube to each of the depth positions corresponding to the positions of the respective soil layers of a plurality of types of soil layers constituting the ground portion on which the ground improvement body is created, inside the extrapolation tube. A sensor placement step of fixedly placing at least one acceleration sensor for detecting vibration;
After the sensor placement step, the curing material is jetted at a high pressure from the jet nozzle, and the vibration transmitted through the outer cannula by the high pressure jet is fixedly arranged at a depth position corresponding to each soil layer. A vibration recording step of detecting vibration data indicating the detection result detected by the acceleration sensor; and
A construction status confirmation method for confirming a construction status of the high-pressure jet agitator based on the vibration data recorded by the vibration recording step.   The construction state of the high-pressure jet agitator according to claim 1, wherein the observation hole has a depth equal to or greater than a formation depth of the ground improvement body, and the extratubation tube has a length equal to or greater than a formation depth of the ground improvement body. Confirmation method.   In the sensor placement step, at least one long support member having a length equal to or greater than the formation depth of the ground improvement body and a length position corresponding to the depth position of each soil layer of the support member. The sensor support body having a plurality of the acceleration sensors arranged one by one is inserted into the outer cannula, and after the insertion, the outer cannula is filled with a vibration transmitting substance that is a substance capable of transmitting vibration. The construction status confirmation method of the high-pressure jet agitator described.   In the sensor placement step, at least one long support member having a length equal to or greater than the formation depth of the ground improvement body and a length position corresponding to the depth position of each soil layer of the support member. The sensor support body having a plurality of the acceleration sensors arranged one by one is installed in the extrapolation tube so that the sensor support body is fixedly disposed in a state where the sensor support body is in contact with the inner surface of the extratubation tube. How to check the construction status of the high-pressure jet agitator.   5. The sensor placement step according to claim 3 or 4, wherein the outer tube is formed with a lid portion formed at a bottom side end portion that prevents passage of the sensor support when the outer tube is pulled out. The construction status confirmation method of the high-pressure jet agitator described. A ground improvement body that forms the ground improvement body by a high-pressure jet agitator that forms a ground improvement body by high-pressure injection of a hardening material from the injection nozzle of the improvement pipe inserted into the ground and pulling up the improvement pipe while rotating. Creation process,
The ground improvement body characterized by including the construction condition confirmation process which confirms the construction condition of the said high pressure injection agitator by the construction condition confirmation method of the high pressure injection agitator of any one of Claims 1-5. How to build. In the ground improvement body construction work that creates the ground improvement body by the high-pressure jet agitation method, it is a construction status information measuring device for high-pressure agitator that measures the construction status information related to the construction status of the high-pressure jet agitation,
An extrapolation tube that extends from the ground surface to a position below the formation depth of the ground improvement body, provided at a position that is separated from the creation position of the ground improvement body in a radial direction by a preset distance;
An acceleration sensor that is fixedly arranged at least one at a position corresponding to the depth position of each soil layer of a plurality of types of soil layers that constitute the ground portion in which the ground improvement body is formed, and in the extrapolation tube;
A vibration transmitting material which is a material capable of transmitting vibration filled in the outer cannula in which the acceleration sensor is disposed;
And a vibration data recording unit for recording vibration data detected by the acceleration sensor when the ground improvement body is created by the high-pressure jet agitator.

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