JP2007217963A - Ground improvement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground improvement method capable of accurately or easily obtaining information of the ground in a construction field necessary for forming an underground consolidation body and forming a high quality of the underground consolidation body having the same radial size. <P>SOLUTION: In a process boring a guide hole (h), an attainment depth of a boring means 3, the number of rotation of the boring means and a penetration velocity of a boring rod 2 are decided to measure a boring torque, the hardness of the ground is decided from the number of rotation of the boring means, the penetration velocity of the boring rod and the boring torque, a relation of the attainment depth of the boring and the hardness of the ground in a place wherein the guide hole is bored is obtained, and in a process jetting a solidifying agent to the radial outside from a fluid jetting means 9, an attainment distance in the ground of a solidifying agent jet is controlled according to the relation between the attainment depth of the boring means and the hardness of the ground. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ground improvement method for forming a cylindrical ground solid body by injecting a solidifying material (for example, cement milk) into the ground to be improved.

  It is preferable that the columnar underground solid body formed by the ground improvement method has a uniform radial dimension even when the depth is different. In the ground improvement method, the standard design effective diameter is determined according to the ground conditions. Therefore, the cylindrical submerged solid body whose radial dimension is equal to the standard design effective diameter is high quality regardless of the depth.

Here, in the ground improvement method, the cemented solidification material is injected at an ultra-high pressure to cut the local ground, and mixed and stirred to create an improved consolidated body in the ground. It becomes smaller and therefore the consolidated body becomes smaller.
Also, in the cohesive soil layer, the N value which is the standard penetration test value is increased, and at the same time, the consolidated body is reduced.
On the other hand, in soft ground, the N value decreases and the consolidated body becomes larger than necessary.

  However, conventionally, no survey boring is performed at the construction site or in the vicinity thereof, and the ground improvement method is sometimes constructed based on the data of the survey boring performed at a past time in the neighboring area. And in the construction concerned, there was a case where the quality of the underground solid body to be created could not be guaranteed.

As another prior art, an optical fiber is vertically built in the ground around the jet pipe of the ground improvement material jet, and the ground improvement material is jetted from the length of the optical fiber cut by the ground improvement material jet. A technique for detecting the depth in real time has been proposed (see Patent Document 1).
Such a technique is useful, but requires labor and cost for separately installing an optical fiber. In addition, since information other than the depth at which the ground improvement material is sprayed cannot be obtained, it is possible to meet the above-mentioned request to create a high-quality underground solid body having the same radial dimension. Absent.
JP-A-5-239825

  The present invention has been proposed in view of the above-described problems of the prior art, and accurately and easily obtains information on the ground at the construction site necessary for constructing an underground solid body, and thus, An object of the present invention is to provide a ground improvement method capable of creating a high-quality underground solid body having the same radial dimension.

  The ground improvement method of the present invention comprises a drilling step (FIG. 2) in which a guide hole (h) is drilled using a drilling rod (2) having a drilling means (3) at the tip, and a fluid jet at the tip. The step of inserting the injection rod (10) provided with the means (9) into the guide hole (h) (FIG. 4) and the radial direction (horizontal direction: slightly inclined with respect to the horizontal plane) from the fluid injection means (9) Including an injection step (FIG. 5) for rotating and pulling up the injection rod (10) while injecting a jet (J) of a solidified material (for example, cement milk) to the outside. In FIG. 2), the depth of arrival of the drilling means (3), the rotation speed of the drilling means (3) and the penetration speed of the drilling rod (2) are determined and the drilling torque is measured. ) Rotation speed, penetration speed of drilling rod (2) and drilling torque determine the hardness of the ground at the depth of reach Therefore, the relationship between the depth of the drilling means (3) at the location where the guide hole (h) is drilled and the hardness of the ground at the depth of arrival is obtained. Drilling means (3) determined in the process (FIG. 2), controlling the diameter of the underground solid body (K) formed in the ground from the relationship between the depth of arrival and the hardness of the ground at the depth of arrival. (Claim 1).

  In the present invention, in the injection step (FIG. 5), it is preferable to control the rotation speed of the injection means (monitor 9) in accordance with the hardness of the ground at the depth of the drilling means (FIGS. 8 and 9). Claim 2).

  Further, in the present invention, in the injection step (FIG. 5), a fluid (for example, solidified material jet J) is injected from the fluid injection rod (10: or monitor 9) in accordance with the hardness of the ground at the depth of the drilling means. Or water) is preferably controlled (FIGS. 10 and 11: Claim 3).

  Further, in the present invention, in the jetting step (FIG. 5), the fluid jetted from the fluid jetting means (9) corresponding to the hardness of the ground at the drilling means reaching depth (for example, solidified material jet J or water). It is preferable to control the flow rate (for example, solidified material flow rate) (FIGS. 12 and 13: Claim 4).

  In addition, in the present invention, in the injection step (FIG. 5), the concentration of the solidified material (cement milk concentration) in the slurry is measured (step S21 in FIG. 9), and the solidified material concentration is the first threshold value (solidified). If it is thinner than the lower limit value of the material concentration, control is performed to shorten the reach of the solidifying material jet in the ground (steps S25, S25A, S25B), and the solidified material concentration is the second threshold value (the upper limit of the solid material concentration allowable value). If it is darker than (value), it is preferable to perform control to increase the reach distance of the solidifying material jet in the ground (steps S24, S24A, S24B) (FIGS. 9, 11, and 13: claim 5).

Here, when controlling the reach of the solidifying material jet (J) in the ground in the injection step (FIG. 5), in order to increase the reach of the solidifying material jet (J) in the ground, for example, injection The rotational speed of the rod (10) is reduced, the injection pressure of the solidified material jet (J) from the fluid ejecting means (9) is increased, or the amount of solidified material ejected from the fluid ejecting means (9) ( Increase the injection flow rate.
On the other hand, in order to shorten the reach of the solidifying material jet (J) in the ground, for example, the rotational speed of the injection rod (10) is increased or the solidifying material jet (J) from the fluid injection means (9) is used. The injection pressure may be reduced, or the injection amount (injection flow rate) of the solidified material from the fluid injection means (9) may be reduced.

  In addition, the ground improvement method of the present invention is the depth and N value in the vicinity of the construction site (when the weight is dropped on the soil of the sample, the number of drops required for the weight to penetrate into a predetermined dimension: ground strength Alternatively, a survey boring process for performing survey boring while determining the soil hardness), a process for measuring the depth and excavation torque by drilling a guide hole (h) in the vicinity of the survey boring point, and the process The process of obtaining the characteristics of the excavation torque and N value from the depth and excavation torque measured in the above and the depth and N value determined in the survey boring process, and using the drilling rod (2) at the construction site, the guide hole (h ), In which the N value for a specific depth is estimated based on the characteristics of the determined excavation torque and the N value, and the construction specification is determined from the estimated N value. Appropriate at that depth based on The injection amount of solidified material (for example, cement), the injection pressure, the lifting speed (of the monitor 9 or the injection rod 10) are determined, and the solidified material jet (J) is injected radially outward from the fluid injection means (9). An injection step of rotating and pulling up the injection rod (10) while the injection step determines the solidified material (for example, cement) injection amount, injection pressure, and the determined amount corresponding to the depth of the fluid injection means (9). The construction is performed at a pull-up speed (of the monitor 9 or the injection rod 10) (Claim 6).

According to the present invention having the above-described configuration, first, when the guide hole (h) is drilled using the drilling rod (2), that is, where the improved body is made (just point) (in the drilling process). At the time of FIG. 2), the hardness of the ground at the reaching depth is determined, and when the solidified material (for example, jet J such as cement milk) is injected radially outward (injection process: FIG. 5), the determined ground Work with construction specifications that match the hardness of the machine. Specifically, the solidification material is injected by controlling any one of the rotation speed of the injection rod (10) or the injection means (monitor 9), the injection pressure of the solidification material, and the injection flow rate of the solidification material.
That is, the reach of the solidifying material jet (J) in the ground is constant, corresponding to the “ground hardness” which is the dominant factor in the reach of the solidifying material jet (J) in the ground. Since it is controlled, the diameter (improved diameter) of the formed underground solid body can be made constant.

In the injection step (FIG. 5), the mixture of the injected solidified material and the drilled soil is discharged to the ground side through the guide hole (h) as a slurry.
Here, the concentration of the solidified material in the slurry is measured, and when the solidified material concentration is high, it can be determined that the reach distance of the solidified material is shorter than the standard design effective diameter. On the other hand, when the solidifying material concentration is low, it can be determined that the reach of the solidifying material is longer than the standard design effective diameter.
In this case, the solidifying material concentration in the slurry is preferably measured while the slurry is present in the ground. However, it is possible to measure the solidified material concentration in the slurry on the ground.

  In the present invention, the concentration of the solidified material in the slurry is measured in the injection step, and when the concentration of the solidified material is high, the control for increasing the jet reach distance (reducing the rotation speed of the injection rod or the injection means, If the concentration of the solidified material is low, control for shortening the jet arrival distance (of the injection rod or the injection means) is performed. If the rotational speed is increased, the injection pressure of the solidified material is reduced, or the control of reducing the injection flow rate of the solidified material is performed (Claim 5), it is independent of the depth of the fluid injection means (9). In addition, since the reach of the solidifying material jet (J) becomes uniform, the radial dimension of the formed cylindrical underground solid body becomes uniform, and a high quality underground solid body is formed.

Further, in the present invention, referring to the result of the survey boring performed in the vicinity of the construction point in advance, the N value at each depth is estimated in the drilling process, and from the estimated N value, according to a known construction specification, An appropriate solidified material (for example, cement) injection amount, injection pressure, and pulling speed (of the monitor 9 or the injection rod 10) at a depth are determined. In the injection process, the determined solidified material (for example, cement) injection amount is determined for each depth. If the construction is carried out at the injection pressure and the pulling speed of the monitor 9 (or the injection rod 10) (Claim 6), it is accumulated based on the results of the survey boring conducted in the vicinity of the construction point and based on the existing construction results. Based on the known construction specifications made, it is possible to construct at an appropriate solidifying material (for example, cement) injection amount, injection pressure, and pulling speed of the monitor 9 (or injection rod 10). Come.
As a result, the construction efficiency is improved and the quality of the ground submerged structure is maintained.

Hereinafter, with reference to an accompanying drawing, an embodiment in the ground improvement construction method of the present invention is described.
First, a first embodiment will be described with reference to FIGS.
Here, prior to the description of the first embodiment, an outline of construction equipment will be described.

In FIG. 1, a construction machine 1 on which a drilling rod 2 for drilling a guide hole h is installed on the ground side of the construction area.
A drilling means 3 is attached to the tip of the drilling rod 2, and a data collecting / transmitting unit 4 is provided on the ground side of the drilling means 3,

The data collection / transmission unit 4 in the drilling rod 2 includes a power supply unit 41, a transmission antenna 42, a transmission unit 43, and a drilling torque measuring device 44. The excavation torque measuring device 44 is configured to measure the excavation torque (resistance torque) received by the drilling rod 2 during drilling or survey boring of the guide hole h, and a known or commercially available one can be applied. .
In FIG. 1, the excavation torque measuring device 44 is provided with the data collection / transmission unit 4 in the drilling rod 2, but may be provided in the construction machine 1.

Although not shown, when the drilling rod 2 is lowered, the depth of the drilling means 3 is automatically measured by the construction machine 1. Then, the drilling torque of the drilling means 3 at that depth is measured by the drilling torque measuring device 44 and is transmitted from the transmitter 43 via the transmitting antenna 42 as electromagnetic waves.
Further, the descent speed data of the hole drilling means 3 is also transmitted as electromagnetic waves via the transmitting antenna 42 as the amount of change in depth over time.
The electromagnetic wave transmitted from the transmitting antenna 42 is configured to be received by the receiver 6 via the receiving antenna 5 installed on the ground.

The measurement data received by the receiver 6 is sent to an analysis personal computer 7 which is a data processing device, and data processing is performed. Then, the hardness of the ground for each depth is calculated from the torque, the rotation speed (or the number of rotations) of the hole drilling means 3 and the penetration speed of the hole drilling means 3, and “depth” is stored in the database built in the analysis personal computer 7. It is memorized as a map showing the relationship between the “ground hardness” and the ground.
The analysis personal computer 7 is connected to a printer 8 which is a data output means, and is configured to output various data as required.

As described above, according to the illustrated first embodiment, the hardness of the ground can be determined (by the just point) from the measurement results of various numerical values (characteristic values) at the location where the improved body is created. And since it can construct with the construction specification which suited the hardness of the determined ground, the diameter of the underground solid body formed can be made substantially the same.
In order to make the diameters of the underground solid bodies formed substantially the same, specifically, the rotation speed of the injection rod 10 described later and the injection pressure of the monitor 9 which is fluid injection means described later are controlled.

  In FIG. 1, the guide hole is first drilled in creating the improved body, and the equipment for drilling the guide hole is described. At the same time, the equipment for measuring the hardness and the like of the construction area at the same time as the drilling is also described.

Next, with reference to FIGS. 2-6, the ground improvement construction method of this invention is demonstrated for every process order in order of a process.
FIG. 2 shows a process of drilling the guide hole h using the equipment described in FIG. 1 (a drilling process). That is, the soil G is drilled by the drilling means 3 attached to the tip of the drilling rod 2, and the guide hole h is drilled.

The drilling step in FIG. 2 is performed until digging to a predetermined depth hb (see FIG. 3).
During the drilling process of FIG. 2, the drilling torque for each depth is measured by the torque meter 44 of the data transmission unit 4, and the data is continuously sent to the ground analysis personal computer 7 by the method described above.
When the guide hole h is drilled to a predetermined depth hb, the drill rod 2 is lifted to the ground side (FIG. 3: drill rod lifting process).

Here, with reference to FIG. 7, the flow of the operation | work which determines the hardness of a ground at the time of drilling of the guide hole h of a ground improvement location in the drilling process of FIG. 2 is demonstrated.
Step S1 shows a state of waiting for the start of drilling of the guide hole h (a loop in which S1 is “NO”). When the drilling of the guide hole h is started (YES in step S1), the drilling torque is also measured at every predetermined control cycle (see step S7), and the depth of the drilled portion is determined by the construction machine 1. Then, the number of rotations of the drilling rod 2 is determined, and the penetration speed of the drilling rod 2 is also determined (step S2).

In the next step S3, the depth, the number of revolutions of the drilling rod 2 and the penetration speed are output to the analysis personal computer 7 which is a means for determining the hardness of the ground, and the torque measurement value measured by the torque meter 44 is displayed. It is transmitted to the personal computer 7 for analysis.
Then, the analysis personal computer 7 obtains the hardness of the ground at the depth from the data, and records the obtained hardness of the ground in the database as decision data (step S4).

In step S5, it is determined whether or not the drilling of the guide hole h is completed. If the drilling of the guide hole h is completed (YES in step S5), the drilling rod 2 is lifted to the ground in step S6. End control.
On the other hand, if the drilling rod has not been completed yet, the process proceeds to step S7, and if the time of one control cycle has elapsed (YES in step S7), the process returns to step S2, and the control after step S2 is repeated.

In the step shown in FIG. 4, an injection rod 10 in which a fluid injection means (monitor: in this specification, the solidification allowance injection means is described as “monitor”) 9 is attached to the tip at the bottom hb of the drilled guide hole h. Suspend.
Here, the monitor 9 is provided with a concentration meter (not shown) so that the concentration meter can measure the concentration of the solidified material in the slurry in the ground. It is also possible to provide a measuring device for measuring the concentration of the solidified material in the slurry on the ground side instead of the monitor 9. However, for the reason described later with reference to FIG. 9, it is preferable that the densitometer is provided in the monitor 9 in order to improve the accuracy of the underground solid body to be formed.

  In the step (injection step) of FIG. 5, a solidified material (for example, cement milk) jet (jet J) is injected from the monitor 9, and the injection rod 10 is rotated as indicated by the arrow R, as indicated by the arrow U. In the same way, it is lifted up (to the ground side) in the figure.

Then, the soil G is excavated or cut by the injected solidifying material jet J, and is rotated by rotating (R) the mixing rod 10 to mix the solidified material and the in-situ soil. Then, by lifting the injection rod 10 to the ground side as indicated by the arrow U, the in-situ soil is excavated or cut in a predetermined region in the axial direction of the injection rod 10 and mixed with the solidified material. .
The in-situ soil that is excavated or cut and mixed with the solidified material solidifies over time.

FIG. 6 shows a state in which the monitor 9 is pulled out to the ground after the solidified material injection is finished and the underground consolidated body K is completed.
Although not clearly shown in FIG. 5, the monitor 9 is provided with a concentration sensor for measuring the cement milk concentration in the slurry.

  In FIG. 5, based on the determined ground hardness (see FIGS. 2 and 7), the rotational speed of the monitor 9, the injection pressure of the solidified material (for example, cement milk) from the monitor 9, or the monitor 9 One of the injection flow rates of the solidified material (for example, cement milk) is controlled.

FIG. 8 is a flowchart showing the control of the rotation speed of the monitor 9.
Hereinafter, based on FIG. 8, the formation control method of an underground solid body in the case of using the rotational speed of the monitor 9 as a control parameter will be described.

Here, when the ground is hard, control is performed to reduce the rotation speed of the monitor 9 so that the jet of the solidified material can reach a predetermined distance, in other words, to extend the reach of the solidified material jet. .
On the other hand, when the ground is soft, control is performed to increase the rotational speed of the monitor 9 so that the jet of the binder does not exceed a predetermined distance, that is, the reach distance of the binder jet is shortened.

  In step S11 of FIG. 8, the depth of the injection means (monitor) 9 is determined (confirmed), the hardness of the ground at that depth is read from the database of the personal computer for analysis (step S12), and monitoring is performed based on the hardness of the ground. 9 is determined (step S13).

That is, in step S13, when the ground is hard, the rotational speed of the monitor 9 which is an injection means is decreased.
On the other hand, when the ground is not hard (soft), the rotation speed of the monitor 9 which is an injection means is increased.

In the next step S14, it is determined whether or not the determined rotational speed of the monitor 9 is substantially the same as the actual rotational speed (current rotational speed).
Here, “substantially the same” means that the deviation between the numerical value of the rotational speed determined in step S13 and the numerical value of the actual rotational speed (or the current value) is within a predetermined range. The predetermined range is determined on a case-by-case basis for each construction site.
If the determined rotational speed and the current rotational speed are approximately the same (YES in step S14), the process proceeds to step S16. On the other hand, if the rotational speed is not approximately the same (the rotational speed determined in step S13 and the current rotational speed). If the difference from the speed exceeds the predetermined range (NO in step S14), the process proceeds to step S15.

In step S15, the rotational speed of the monitor 9 is adjusted or controlled to a numerical value determined based on the hardness of the ground (the numerical value determined in S13). Then, the process proceeds to step S16.
In step S16, the solidified material is ejected while rotating the monitor 9 and pulled up to the ground side, and the formation of the underground consolidated body is executed (implementation work). Then, after a predetermined time has elapsed (or at a predetermined control timing), the process proceeds to step S17.
In step S17, it is determined whether or not the drilling is completed. If completed (step S17 is YES), the control is terminated. If the drilling is not completed (NO in step S16), the process waits until the time per control cycle elapses in step S18, returns to step S11, and repeats step S11 and subsequent steps.

In FIG. 8, the hardness of the ground is measured at a location (just point) where the improved body is made, and the rotation speed of the spray rod is adjusted to match the measured hardness of the ground.
In other words, in accordance with “the hardness of the ground” which is a factor that is dominant in the reach distance of the solidifying material jet J in the ground, the reach of the solidifying material jet J in the ground is controlled to be constant. Therefore, the diameter (improved diameter) of the formed underground solidified body can be made constant.

The control executed in the process shown in FIG. 5 is not limited to the control explained in FIG. 8, but the control explained in FIG. 9 is performed on the back side of the control explained in FIG.
That is, in the control method of FIG. 9, it is determined whether cutting and stirring are properly performed based on the cement concentration in the slurry, and the rotation speed of the monitor 9 is controlled in accordance with the cement concentration.

In the control of FIG. 9, first, in step S21, the cement concentration in the slurry is measured. In the next step S22, it is determined whether or not the measured value of the cement concentration is within the allowable range, that is, whether or not the measured value is not less than the allowable lower limit value and not more than the allowable upper limit value.
When the measured value of the cement concentration is higher than the allowable upper limit value, the amount of cutting of the soil is small, so the reach distance of the cement milk jet J in the soil, that is, the diameter of the ground solid body is larger than the standard design effective diameter. It can be seen that the length is shortened. Therefore, in order to increase the reach distance (the diameter of the underground solid body) of the cement milk jet J, it is necessary to perform control to reduce the rotational speed of the monitor 9 that is the injection means.

  On the other hand, when the measured value of the cement concentration is thinner than the allowable lower limit value, the amount of cutting of the soil is large. Therefore, the reach distance of the cement milk jet J in the soil, that is, the diameter of the ground solid body is effective for the standard design. It can be seen that it is longer than the diameter. Therefore, in order to shorten the reach distance (the diameter of the underground solid body) of the cement milk jet J, it is necessary to perform control to increase the rotational speed of the monitor 9 that is the injection means.

If the cement concentration in the slurry is appropriate (more than the allowable lower limit value and lower than the allowable upper limit value), the solidifying material jet (J) has reached the desired range in the ground, and cutting and stirring are performed. Therefore, the process proceeds to step S23 in order to maintain the rotational speed of the monitor 9 as the injection means at present.
When the cement concentration is high (the measured value exceeds the allowable upper limit value and the reach distance of the cement milk jet J is too short), only a region narrower than the desired range can be cut and stirred. In this case, the process proceeds to step S24.
When the cement concentration is low (the measured value is less than the allowable lower limit value and the reach distance of the cement milk jet J is too long), a wider range than the desired range is cut and stirred. In this case, the process proceeds to step S25.

Here, with reference to FIG. 16, the allowable lower limit value and the allowable upper limit value of the cement concentration in step S22, that is, an appropriate range of the cement concentration will be described.
The upper table in FIG. 16 shows the diameter Φ of the ground solid body (improved body) in the sand ground and the specific gravity of the slurry during the improvement work, and the lower table in FIG. 16 shows the ground solid body in the clay ground. The diameter (Φ) of the body (improvement) and the specific gravity of the slurry during the improvement work are shown.
Here, the specific gravity of the slurry during the improvement operation is a parameter corresponding to the cement concentration.

As is clear from the upper table and lower table in FIG. 16, the specific gravity or cement concentration of the slurry differs depending on the type of ground and the required diameter Φ of the ground solid body (improved body).
If the tolerance of the diameter Φ of the ground solid body (improved body) is ± 0.5 m, the appropriate range of the cement concentration in the case of sand ground is the range described below from the table at the top of FIG. Become.

That is, if the target diameter of the underground solid body (improved body) is 3.0 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.66 to 1.71.
If the target diameter of the ground solid body (improved body) is 3.5 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.69 to 1.72.
If the target diameter of the ground solid body (improved body) is 4.0 m, the appropriate range of the cement concentration is a range where the specific gravity of the slurry is 1.71 to 1.74.
If the target diameter of the underground consolidated body (improved body) is 4.5 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.72 to 1.75.

Similarly, if the tolerance of the diameter Φ of the ground solid body (improved body) is ± 0.5 m, the appropriate range of cement concentration in the case of clay ground is as follows from the table at the bottom of FIG. It is.
If the target diameter of the underground solid body (improved body) is 3.0 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.560 to 1.575.
If the target diameter of the ground consolidated body (improved body) is 3.5 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.570 to 1.580.
If the target diameter of the underground consolidated body (improved body) is 4.0 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.575 to 1.580.
If the target diameter of the underground consolidated body (improved body) is 4.5 m, the appropriate range of the cement concentration is a range in which the specific gravity of the slurry is 1.580 to 1.585.

  Regarding the allowable lower limit value and the allowable upper limit value in step S22 of FIG. 9 or the appropriate range of the cement concentration, the numerical values described above with reference to FIG. 16 will be described with reference to step S22 of FIG. 11 and step S22 of FIG. Are the same.

In step S23, the rotation speed of the monitor 9 is maintained as it is, and the process proceeds to step S26.
In step S24, control is performed to increase the jet arrival distance, that is, control is performed so as to decrease the rotational speed of the monitor 9, and then control proceeds to step S26.
In step S25, control is performed to shorten the jet reach distance, that is, control is performed to increase the rotational speed of the monitor 9, and then control proceeds to step S26.

In step S26, it is determined whether or not the injection process is completed.
If the injection process has been completed (YES in step S26), the control is terminated as it is. On the other hand, if the injection process has not yet been completed (NO in step S26), the process waits until the time per control cycle elapses (NO loop in step S27).
If the time per control cycle has elapsed (YES in step S27), the process returns to step S21, and step S21 and subsequent steps are repeated again.

  As a premise of the control explained in FIG. 9, in the injection process of FIG. 5, the mixture of the injected solidified material and the drilled soil is discharged to the ground side through the guide hole h as a slurry. In the control described with reference to FIG. 9, the solidified material concentration in the slurry is measured, and when the solidified material concentration is high, it is determined that only a region narrower than the desired range is formed by cutting and stirring. When the material concentration is low, it is determined that a wider range than the desired range is being cut and stirred.

  Here, it is difficult to accurately measure the cement concentration (concentration concentration) in the slurry unless it is measured in real time. For example, the slurry ejected to the ground side may be mixed with a plurality of types of slurries having different concentrations of the binder. Therefore, in the control shown in FIG. 9 (including the control shown in FIG. 11 and the control shown in FIG. 13), the cement concentration in the slurry is a concentration (not shown) provided in the monitor 9 (see FIGS. 4 and 5). It is preferable to measure with a meter.

In FIG. 9, the solidification material concentration in the slurry is measured in the injection process, and when the solidification material concentration is high, control is performed to increase the jet reach distance. Control is performed to shorten the reach.
By controlling in this way, even if the depth of the monitor 9 changes, the reaching distance of the solidifying material jet J becomes the same, so that a high-quality underground solid body having a uniform radial dimension can be created.

Here, in FIGS. 8 and 9, the parameter to be controlled is the rotation speed of the injection means (monitor 9), but other parameters can be controlled.
For example, in the control shown in FIGS. 10 and 11, the injection pressure of the solidified material (for example, cement milk) from the monitor 9 is selected as a parameter to be controlled, and in the control shown in FIGS. The injection flow rate of the solidified material (for example, cement milk) from the monitor 9 is selected as a parameter to be controlled.

The control shown in FIGS. 10 and 11 (hereinafter referred to as a first modification) will be described.
10 is substantially the same as the flowchart shown in FIG. 8, steps S11, S12, and S16 to S18 in FIG. 10 are the same as those in FIG. 8, and steps S13A to S15A in FIG. 10 are steps S13 to S13 in FIG. Corresponds to S15.
That is, in FIG. 10, the injection pressure of the solidified material from the monitor 9 is determined based on the hardness of the ground obtained in step S12 (step S13A), and if the ground is hard, the injection pressure of the consolidated material is increased. If the ground is soft, the injection pressure is reduced.

In the next step S14A, it is determined whether or not the determined injection pressure is substantially the same as the actual injection pressure (the current solidification material injection pressure), and the determined injection pressure and the current injection pressure are approximately the same. If there is (step S14A is YES), the process proceeds to step S16. On the other hand, if not substantially the same (if the difference between the injection pressure determined in step S13A and the current injection pressure exceeds a predetermined range) (step S14A NO), the process proceeds to step S15A.
In step S15A, the injection pressure of the solidified material from the monitor 9 is adjusted or controlled to a numerical value determined based on the hardness of the ground (the numerical value determined in S13A). Then, the process proceeds to step S16. The subsequent steps are the same as in FIG.

  11 is substantially the same as the flowchart shown in FIG. 9, steps S21, S22, S26, and S27 in FIG. 11 are the same as those in FIG. 9, and steps S23A to S25A in FIG. 11 are steps S23 to S23 in FIG. This corresponds to S25.

That is, in FIG. 11, the cement concentration in the slurry is determined in step S22. If the cement concentration in the slurry is appropriate (above the allowable lower limit value and below the allowable upper limit value), the solidifying material jet (J) is in the ground. Is determined to have reached the desired range, and the process proceeds to step S23A.
If the cement concentration is high (the measured value exceeds the allowable upper limit and the reach of the cement milk jet J is too short), it is determined that the reach of the solidified material is too short than the standard design effective diameter, Proceed to step S24A.
If the cement concentration is low (the measured value is less than the allowable lower limit value and the reach distance of the cement milk jet J is too long), it is determined that the reach distance of the solidified material is too long than the standard design effective diameter, and step S25A. Proceed to

In step S23A, the solidifying material injection pressure is maintained as it is, and the process proceeds to step S26.
In step S24A, in order to increase the jet reach distance, control is performed to increase (increase) the solidified material injection pressure from the monitor 9, and then the process proceeds to step S26.
In step S25A, control is performed to shorten the jet reach distance and control is performed so as to decrease (depressurize) the solidified material injection pressure from the monitor 9, and then the process proceeds to step S26.
Step S26 and subsequent steps are the same as those in FIG.

  Other configurations and operational effects of the first modified example of FIGS. 10 and 11 are the same as the control shown in FIGS.

Next, the control shown in FIGS. 12 and 13 (hereinafter referred to as a second modification) will be described.
12 is substantially the same as the flowcharts of FIGS. 8 and 10, steps S11, S12, and S16 to S18 of FIG. 12 are the same as those of FIGS. 8 and 10, and steps S13B to S15B of FIG. 8 corresponds to steps S13 to S15 of FIG. 8 and steps S13A to S15A of FIG.
In FIG. 12, the injection flow rate of the solidified material from the monitor 9 is determined based on the hardness of the ground obtained in step S12 (step S13B). If the ground is hard, the solidified material injection flow rate is increased. If is soft, the flow rate of the binder is decreased.

In the next step S14B, it is determined whether or not the determined solidification material injection flow rate is substantially the same as the actual solidification material injection flow rate (current solidification material injection flow rate), and the determined rotation speed and the current rotation speed are determined. Are approximately the same (YES in step S14B), the process proceeds to step S16. On the other hand, if they are not approximately the same (the difference between the solidified material injection flow rate determined in step S13B and the current solidified material injection flow rate falls within a predetermined range. If so (NO in step S14B), the process proceeds to step S15B.
In step S15B, the solidifying material injection flow rate from the monitor 9 is adjusted or controlled to a numerical value determined based on the hardness of the ground (the numerical value determined in S13B). Then, the process proceeds to step S16. The subsequent steps are the same as those in FIGS.

  13 is substantially the same as the flowchart shown in FIG. 9 or FIG. 11, steps S21, S22, S26, and S27 in FIG. 13 are the same as those in FIGS. 9 and 11, and steps S23B to S25B in FIG. This corresponds to steps S23 to S25 in FIG. 9 or steps S23A to S25A in FIG.

In FIG. 13, in step S22, the cement concentration in the slurry is determined. If the cement concentration in the slurry is suitable (above the allowable lower limit value and lower than the allowable upper limit value), the solidifying material jet (J) is desired in the ground. It is determined that the range has been reached, and the process proceeds to step S23B.
If the cement concentration is high (the measured value exceeds the allowable upper limit and the reach of the cement milk jet J is too short), it is determined that the reach of the solidified material is too short than the standard design effective diameter, Proceed to step S24B.
If the cement concentration is low (the measured value is less than the allowable lower limit value and the reach distance of the cement milk jet J is too long), it is determined that the reach distance of the solidified material is too long than the standard design effective diameter, and step S25B Proceed to

In step S23B, the injection flow rate of the solidified material is maintained as it is, and the process proceeds to step S26.
In step S24B, in order to increase the jet reach distance, control is performed to increase the injection flow rate from the monitor 9, and then the process proceeds to step S26.
In step S25B, control to shorten the jet reach distance and control to decrease the injection flow rate from the monitor 9, and then the process proceeds to step S26.
Step S26 and subsequent steps are the same as those in FIGS.

  Other configurations and operational effects of the second modified example of FIGS. 12 and 13 are the same as those of the control shown in FIGS. 8 and 9 or the first modified example.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In the first embodiment shown in FIGS. 1 to 13, any one of the rotation speed of the monitor 9, the injection pressure of the solidified material, and the injection flow rate of the solidified material is selected based on the hardness of the ground determined in the drilling step. Two parameters are determined. On the other hand, in the second embodiment shown in FIGS. 14 and 15, the N value at each depth (in the soil of the sample) is determined in the drilling process with reference to the result of the survey boring executed in advance in one of the construction areas. When the weight is dropped, the number of drops required for the weight to penetrate into a predetermined dimension is estimated: a numerical value representing ground strength or soil hardness), and the known N value is used for the estimated construction. According to the specifications, an appropriate solidifying material (for example, cement) injection amount, injection pressure, and pulling speed of the monitor 9 (or injection rod 10) at the depth are determined. In the injection process, the determined solidifying material (for example, for each depth) The cement is applied at the injection amount, the injection pressure, and the pulling speed of the monitor 9 (or the injection rod 10).

In the second embodiment, the survey boring is performed in a known manner, and the illustration is omitted except that the related portions are described in the flowchart of FIG.
Further, the equipment for constructing the second embodiment is substantially the same as that shown in FIG. 1 except for the part related to the control mechanism of FIG. The drilling process is the same as that shown in FIG. 2 except for the contents related to the control mechanism of FIG. 14, and the injection process is also shown in FIG. 5 except for the contents related to the flowchart of FIG. It is the same as shown.

A control mechanism for executing the second embodiment shown in FIG. 14 is indicated by reference numeral 100 as a whole, and is configured by the analysis personal computer 7 in FIG. 1 or provided in the construction machine 1. .
The control mechanism 100 includes a central processing unit 110 (C.U.), a database 112 (storage device), an N value determining unit 114, a drilling torque-N value characteristic determining unit 116, an N value estimating unit 118, An injection amount, an injection pressure, and a pulling speed determination means 120 are provided.

As will be described later with reference to FIG. 15, the N value determination unit 114 obtains an N value for a certain depth from the survey boring data. The obtained N value is input to the excavation torque-N value characteristic determining means 116 together with the depth data corresponding to the N value.
In addition to the depth and N value data from the N value determining unit 114, the excavation torque-N value characteristic determining unit 116 includes the depth when the guide hole is drilled in the vicinity of the location where the survey boring has been performed and the excavation at the depth. Torque is input. Thereby, the excavation torque-N value characteristic determination means 116 determines the correspondence or characteristic between the excavation torque and the N value.
The correspondence or characteristic of the depth, the excavation torque and the N value obtained by the excavation torque-N value characteristic determining means 116 is sent to the database 112 and stored therein.

The N value estimating means 118 receives the depth of the drilling process and the excavation torque at the depth during construction, and the correspondence between the excavation torque and the N value from the database 112. And based on the said correspondence, the N value in the depth is determined as an estimated value from the excavation torque in each depth of the drilling step. In other words, the N value estimation unit 118 functions to determine the correspondence between the depth and the N value.
The determined estimated value of the N value is sent to the injection amount, the injection pressure, and the lifting speed determination means 120.

The injection amount, injection pressure, and pulling speed determination means 120 are input with the determined N value estimated values (depth and N value estimated values), and also have the construction specifications stored in the database 112. Entered. This construction specification is obtained from conventional construction data, and defines the N value in the construction area, the optimum cement injection amount, the injection pressure, and the pulling speed of the monitor 9. The injection amount, the injection pressure, and the lifting speed determination means 120 are based on the estimated value of N value at a certain depth (hereinafter referred to as “estimated N value”) and the cement injection amount at a certain depth based on the construction specifications. The injection pressure and the lifting speed of the monitor 9 are determined, and the relationship between a certain depth and the cement injection amount, the injection pressure and the lifting speed of the monitor 9 at the depth is determined.
The relationship between the depth, the cement injection amount, the injection pressure, and the lifting speed of the monitor 9 is stored in the database 112 and is sent to the central processing unit 110 as necessary.

Next, the construction procedure of the second embodiment will be described with reference mainly to FIG.
First, survey boring (detailed illustration is omitted) is performed using survey boring equipment (not shown) in any of the construction areas where the ground improvement method according to the second embodiment is to be implemented. And the N value at each depth is measured (step S39 in FIG. 15).

Next, a guide hole is drilled using the construction machine 1 in the vicinity of the construction site for the survey boring. When drilling the guide hole, the depth and excavation torque at the depth (measurable by the construction machine 1) are measured (step S40).
Then, the depth and N value obtained in the survey boring (step S39) and the depth and excavation torque obtained in the guide hole drilling (step S40) performed in the vicinity of the survey boring location , N value determination means 114. Here, since the depth is common, the excavation torque-N value characteristic determining means 116 determines the characteristics of the excavation torque and the N value from the parameter obtained in step S39 and the parameter obtained in step S40. Is determined and stored in the database 112 (step S41).

If the characteristics of the excavation torque and the N value are obtained, the process proceeds to step S42, and the drilling process is executed at the point where the ground improvement method is to be constructed (step S42). Here, the drilling step is as described with reference to FIG.
When performing the drilling step, the depth and the excavation torque at the depth are measured by the construction machine 1, and the relationship between the depth and the excavation torque is stored in the database 112 (step S43).

If the excavation torque at a certain depth is determined, the N value estimation means 118 estimates the N value at the depth based on the characteristics of the excavation torque and the N value stored in the database 112 (step S44). .
If the N value is estimated, the cement (solidification) at each depth in the subsequent injection process by the injection amount, injection pressure, and pulling speed determination means 120 based on the construction specifications obtained from the accumulation of past construction results. The optimal value of the injection amount of the material), the injection pressure, the monitor 9 or the lifting speed of the injection rod 10 is obtained. Then, the determined optimum values of the injection amount, the injection pressure, and the lifting speed for each depth are stored in the database 112 (step S45).

In this manner, when the injection amount, injection pressure, and pulling speed for each depth are determined, the injection process as shown in FIG. 5 is started (step S46).
In the injection process, the central processing unit 110 controls the cement (solidified material) injection amount, the injection pressure, and the monitor 9 or the pulling-up speed of the injection rod 10 determined at step S45 for each depth. (Step S47). Then, the control (step S48 is NO loop) such that the injection amount, the injection pressure, and the pulling speed obtained in step S45 are continued until the injection process ends (step S48 is YES).

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated first embodiment, the case of automatic control has been described, but it is also possible to perform various processes manually by an operator.

The block diagram which showed the structure of the whole installation in the guide hole drilling process of 1st Embodiment of this invention. Process drawing which shows the guide hole drilling in the ground improvement construction method of 1st Embodiment. The removal process figure of the drilling rod after the completion of the guide hole in the ground improvement construction method of 1st Embodiment. In the ground improvement method of 1st Embodiment, the erection process drawing of the injection rod to a guide hole. The solidification material injection process figure in the ground improvement construction method of 1st Embodiment. The figure which showed the completion state of the underground solidified body in the ground improvement construction method of 1st Embodiment. The flowchart which showed the control which concerns on calculation of the hardness of the ground which concerns on 1st Embodiment. The flowchart explaining the method of controlling monitor rotational speed based on the hardness of a ground in 1st Embodiment. In 1st Embodiment, the flowchart explaining the method of controlling a monitor rotational speed with the cement density | concentration in a slurry. The flowchart explaining the method to control the injection pressure of a solidification material with the hardness of a ground in the 1st modification of 1st Embodiment. The flowchart explaining the method of controlling the injection pressure of a solidification material with the cement density | concentration in a slurry in a 1st modification. The flowchart explaining the method of controlling the injection flow rate of a solidification material with the hardness of a ground in the 2nd modification of 1st Embodiment. The flowchart explaining the method of controlling the injection flow rate of a solidification material with the cement density | concentration in a slurry in a 2nd modification. The block diagram which shows the control mechanism in 2nd Embodiment of this invention. The flowchart which shows the procedure of 2nd Embodiment. The figure which shows the relationship between the quality of soil, the creation target diameter of an improved body, and the specific gravity of a slurry as a table | surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Construction machine 2 ... Drilling rod 3 ... Drilling means 4 ... Data collection / transmission part 5 ... Receiving antenna 6 ... Receiver 7 ... Data processing apparatus / Processing personal computer 8 ... data output means / printer 9 ... fluid ejecting means / monitor 10 ... ejection rod 41 ... power supply unit 42 ... transmitting antenna 43 ... transmitting unit 44 ...・ Torque meter

Claims (6)

  A drilling step of drilling a guide hole using a drilling rod provided with a drilling means at the tip, a step of inserting a jetting rod provided with a fluid jetting means at the tip into the guide hole, and a radial direction from the fluid jetting means An injection step of rotating and pulling up the injection rod while injecting the jet outward, and in the drilling step, the depth of the drilling means, the rotation speed of the drilling means, and the penetration speed of the drilling rod are determined. Then, the hole drilling torque is measured, the hardness of the ground at the depth of arrival is determined from the rotation speed of the hole drilling means, the penetration speed of the hole drilling rod, and the hole drilling torque. In the injection process, the relationship between the depth of the drilling means and the hardness of the ground at the depth is determined in the injection process. Underground consolidated body to be created Ground improvement method to control means controls the diameter.   2. The ground improvement method according to claim 1, wherein in the spraying step, the rotation speed of the spray rod is controlled in accordance with the hardness of the ground at the depth of the drilling means.   The ground improvement method according to claim 1, wherein in the spraying step, the spray pressure of the fluid sprayed from the fluid spraying means is controlled in accordance with the hardness of the ground at the depth of the drilling means.   2. The ground improvement method according to claim 1, wherein in the spraying step, the flow rate of the fluid sprayed from the fluid spraying means is controlled in accordance with the hardness of the ground at the depth of the drilling means.   In the spraying step, the concentration of the solidified material in the slurry is measured, and when the solidified material concentration is lower than the first threshold, control is performed to shorten the reach distance of the solidified material jet in the ground. The ground improvement construction method according to any one of claims 1 to 4, wherein control is performed to increase a reach distance of the solidifying material jet in the ground when it is deeper than a threshold value of 2.   Survey boring process in which survey boring is performed while determining the depth and N value in the vicinity of the construction site, a process of drilling a guide hole in the vicinity of the survey boring point and measuring the depth and excavation torque, and measurement in the process A process of obtaining characteristics of excavation torque and N value from the depth and excavation torque and the depth and N value determined in the survey boring process, and a drilling process of drilling a guide hole using a drilling rod at a construction site. And in the drilling step, an N value for a specific depth is estimated based on the characteristics of the determined excavation torque and the N value, and an appropriate solidified material at the depth based on the construction specifications from the estimated N value. An injection step of determining an injection amount, an injection pressure, and a lifting speed, rotating and lifting the injection rod while injecting a jet of solidified material radially outward from the fluid injection means, Solidifying material injection amount the determined corresponding to the depth of the fluid injection means, the injection pressure, ground improvement method, characterized in that the construction at a pulling rate.

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