JP3583307B2 - Construction management system in ground improvement method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a construction management system applied to a ground improvement method belonging to the category of the deep mixing treatment method.
[0002]
[Prior art]
The deep mixing method is based on increasing the strength of the original ground by injecting a ground improvement material such as cement slurry into the original ground and mixing it with earth and sand to form a large number of improved piles on the original ground. This is a ground improvement method.
[0003]
FIG. 5 is a schematic diagram of a processing machine 1 applied to such a deep mixing processing method and a construction management system applied thereto. The processing machine 1 vertically supports a screw rod 3 provided with a stirring blade 2 at the tip by a base machine 4, rotates the screw rod 3 by a driving device 5 and penetrates the screw rod 3 to the deepest part of the range to be improved. Pulling out the screw rod 3 while injecting cement slurry as a ground improvement material into the ground from the discharge port provided at the tip of the rod 3 and mixing and stirring the injected cement slurry and earth and sand with the stirring blades 2 To form an improved pile.
[0004]
The construction management system in the case of forming an improved pile by the processing machine 1 includes a slurry flow meter 6, a shaft tachometer 7 of the screw rod 3, a current detector 8 of the driving device 5, a depth meter 9 of the screw rod 3, and An elevating speedometer 10 is provided, and the values detected by these sensors are input to the management device 11, and the injection amount of the cement slurry, the rotation speed of the screw rod 3, the attained depth, the penetration speed and the withdrawal speed are monitored as management items. Is configured. Reference numeral 12 denotes an operation monitor installed on the base machine 4, and reference numeral 13 denotes a personal computer for storing data.
[0005]
[Problems to be solved by the invention]
By the way, in the conventional general deep mixing treatment method as described above, it is inevitable that the volume of the original ground increases because a large amount of cement slurry as a ground improvement material is injected into the original ground. There is a concern that the original ground will rise or adversely affect the surrounding ground, and countermeasures are needed.
[0006]
Therefore, as a measure to prevent the adverse effect on the surrounding ground in the deep mixing method as described above, the volume expansion of the raw ground is avoided by discharging earth and sand equivalent to the injection amount of the cement slurry from the raw ground. Although an earth removal type deep mixing method is also being studied, an effective construction management system that can monitor and properly manage the earth removal amount has not been established yet.
[0007]
[Means for Solving the Problems]
In view of the above circumstances, the invention of claim 1 is that a screw rod having a stirring blade at a tip portion is made to penetrate into the ground, a soil improvement material is injected into the ground through the screw rod, and soil and sand are formed by rotation of the stirring blade. The screw rod is pulled out while being stirred and mixed, and is applied when implementing a soil improvement method in which soil equivalent to the injection amount of the soil improvement material is discharged from the ground by the screw rod, and the depth and rotation of the screw rod In the construction management system that detects and monitors the number, the penetration speed and the withdrawal speed, and the injection amount of the ground improvement material, calculates the estimated soil removal amount by the screw rod based on the rotation speed, and manages the estimated soil removal amount. It is characterized in that it is configured to monitor as an item.
[0008]
The construction management system according to the second aspect of the invention is configured to determine the quality of the construction by comparing the estimated earth removal amount with the injection amount of the ground improvement material.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a specific embodiment of the construction management system of the present invention will be described with reference to FIG. The ground improvement method to which the construction management system of the present embodiment is applied is an earth removal type deep mixing treatment method using the improvement machine 1 shown in FIG. In other words, the improved machine 1 is configured to discharge earth and sand equivalent to the injection amount of the cement slurry when the screw rod 3 is pulled out to avoid volume expansion of the original ground, and accordingly, the construction management system of the present embodiment Is based on the conventional construction management system shown in FIG. 5, adds “discharge amount” to the management item, monitors the amount of discharge by the improved machine 1, and maintains it properly. It is configured to prevent displacement of the ground (swelling and adverse effects on the surrounding ground). Further, in the construction management system of the present embodiment, the “number of blade cutting” is also added as a management item in order to quantitatively grasp the stirring and mixing state of the cement slurry and the earth and sand and appropriately manage the state.
[0010]
That is, as shown in FIG. 1, the construction management system according to the present embodiment includes “material”, “mixing”, “mixing (number of blade cutting)” as management items in quality control, and As the management items, “placement position”, “placement depth”, “landing”, and “discharge amount” are set as management items for managing the displacement of the ground. Among these management items, “material”, “mixing”, “placement position”, “placement depth”, and “landing” are common to the conventional construction management system shown in FIG. “Mixing (blade cutting frequency)” and “discharge amount” are management items added in the present embodiment.
[0011]
Among the management items common to the conventional ones, “material” manages the state of cement slurry (amount of cement and water) as a soil improvement material, and “mixing” indicates the amount of slurry injection detected by the slurry flow meter 6 and the rise and fall. The one that manages whether or not the injection amount per unit depth is appropriate based on the ascending and descending speed of the screw rod 3 detected by the speedometer 10, and the “placement position” determines the formation position of the improved pile by surveying using a transit or the like. What is managed, "placement depth" is the one that manages the position of the screw rod 3 by detecting the position of the screw rod 3 with the depth gauge 9, and "landing" is the operating state of the drive unit 5 and the ascent / descent speed detected by the ammeter 8. From the penetration speed detected by the total 10, it is managed whether or not the tip of the screw rod 3 has reached the deepest part of the improvement target range.
[0012]
In the management items added in the present embodiment, the “discharge amount” is an estimated discharge amount calculated from the rotation speed of the screw rod 3 detected by the shaft tachometer 7, the screw shape and the discharge coefficient. , So that it is equal to the slurry injection amount.
[0013]
In the present embodiment, the calculation of the estimated earth removal amount is performed as follows. The estimated soil removal amount V is a function of the screw cross-sectional area S, the screw pitch P, and the number of revolutions N, and the proportionality constant is defined as V = K · S · P · N
V: Estimated earth removal amount (m ³ )
K: soil removal coefficient S: screw cross-sectional area (m ² )
P: Screw pitch (m)
N: Number of rotations (times)
It is represented by Since the screw cross-sectional area S and the screw pitch P are constants specific to the improved machine, if the value of the soil removal coefficient K is determined, the estimated soil removal amount V can be calculated only by measuring the rotation speed N. The value of dumping factor K, by determining the approximate expression representing the relationship between the value of the measured earth discharging amount V ₁ and S × P × N as shown in FIG. 2 by performing actual measurement test using the improved machine Can be obtained in advance for each improved specification and soil condition.
[0014]
If the soil removal coefficient K, the screw cross-sectional area S, and the screw pitch P determined in advance as described above are input to the management device 11, the rotation speed N detected by the shaft tachometer 7 is input to the management device 11. Only by inputting, the estimated soil removal amount V can be obtained by the above equation. Then, in the construction management system of the present embodiment, every time one improved pile is constructed, the estimated soil removal amount V is calculated and compared with the slurry injection amount detected by the slurry flow meter 6 for construction. The pass / fail judgment is made. The estimated earth removal amount V can be increased or decreased by adjusting the rotation speed N. Therefore, if necessary, the estimated earth removal amount V can be controlled every moment so as to be appropriate.
[0015]
Further, “management number of blades”, which is another management item added in the present embodiment, is a value indicating the number of times blades are cut by each stirring blade 2 when the screw rod 3 is pulled out by a unit length. It is represented by an equation.
[0016]
T = M × n / v
T: Number of blade cutting (times / m)
M: Total number of stirring blades (sheets)
n: Number of rotations (times / minute)
v: Drawing speed (m / min)
[0017]
Since the total number M of the stirring blades 2 in the above equation is a constant unique to the improved machine, the blade cutting frequency T is increased by the rotation speed n detected by the shaft tachometer 7 and the drawing speed v detected by the speedometer 9. It can be obtained based on the formula.
[0018]
Each of the above management items is input to the management device (computer) 11 and evaluated, that is, the quality of the construction is determined, and based on the result, the correction construction is performed as necessary. Then, the construction data is stored in the office computer (PC), and if necessary, appropriate management data, for example, a “construction result table” as shown in FIG. 3 and a “pile driving daily report” as shown in FIG. 4 are printed out. You.
[0019]
According to the construction management system of the present embodiment described above, in addition to being able to perform the same quality control and workmanship management as in the past when soil improvement by the deep mixing processing method of the earth removal type, the estimated earth removal amount is It is possible to perform management so that it is equivalent to the slurry injection amount, and there is an effect that displacement of the original ground can be effectively and rationally prevented.
[0020]
In addition, in the construction management system of the present embodiment, the degree of agitation and mixing of the cement slurry and the earth and sand can be quantitatively grasped by managing the number of times of blade cutting, so that an excellent ground improvement effect can be obtained. .
[0021]
【The invention's effect】
The construction management system according to the first aspect of the present invention calculates the estimated amount of earth removal based on the rotation speed of the screw rod and uses the calculated amount as a management item, so that the amount of earth removal can be appropriately managed, and as a result, There is an effect that displacement of the original ground can be effectively and rationally prevented.
[0022]
The construction management system according to the second aspect of the present invention can determine the quality of the construction by comparing the estimated amount of earth removal with the amount of the ground improvement material injected, thereby ensuring sufficient construction reliability and necessitating repair work. Sex becomes clear.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of a construction management system according to an embodiment of the present invention.
FIG. 2 is a diagram showing a method of determining a soil removal coefficient used in the system.
FIG. 3 is a diagram showing an example of management data in the same system.
FIG. 4 is a diagram showing another example of management data in the system.
FIG. 5 is a diagram showing an outline of a processing machine and a construction management system in a conventional deep mixing processing method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Improvement machine 2 Stirrer blade 3 Screw rod 6 Slurry flow meter 7 Shaft tachometer 8 Current detector 9 Depth meter 10 Speedometer 11 Management device

Claims (2)

A screw rod having a stirring blade at the tip is penetrated into the ground, a ground improvement material is injected into the ground through the screw rod, and the screw rod is pulled out while being stirred and mixed with the earth and sand by the rotation of the stirring blade. Applied when implementing a soil improvement method of discharging soil from the ground by the screw rod corresponding to the injection amount of the improving material, the depth of the screw rod, the number of revolutions, the penetration speed and the withdrawal speed, the soil improving material In the construction management system for detecting and monitoring the injection amount, an estimated earth removal amount by the screw rod is calculated based on the rotation speed, and the estimated earth removal amount is monitored as a management item. Construction management system in the ground improvement method. The construction management system according to claim 1, wherein the estimated amount of soil removal is compared with the amount of ground improvement material injected to determine the quality of the construction.

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