JP2005009169A - Compaction pile formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compaction pile formation method capable of forming a sand pile having such an extent that no inconvenience occurs in terms of strength even if a natural ground is a soft ground and surely controlling a total construction time and the increase of a total amount of sand. <P>SOLUTION: In a compacting process, a compacting force F when the sand is compacted by a casing pipe and a pile diameter D of the sand compacted by the casing pipe is always calculated, and when the compacting force F reaches a predetermined set point F<SB>0</SB>before the pile diameter D of sand reaches a minimum pile diameter D1, compaction has completed when the compacting force F reaches a predetermined set point F<SB>0</SB>, and when the compacting force F reaches the predetermined set point F<SB>0</SB>before the pile diameter D of the sand compacted by the casing pipe reaches a maximum pile diameter D2, compaction has completed when the compacting force F reaches the predetermined set point F<SB>0</SB>, when the pile diameter D of sand reaches the maximum pile diameter D2 before the compacting force F reaches the predetermined set point F<SB>0</SB>, the compaction has completed when it reaches the maximum pile diameter D2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a compacted pile construction method for creating a pile of sand or the like in the ground in order to improve the ground.
[0002]
[Prior art]
As a construction method for improving soft ground or the like, a sand compaction pile construction method (SCP construction method) is conventionally known in which a sand pile is created in a suitable ground in an improvement area to improve the ground. The conventional compacted pile construction method by this sand compaction pile method will be described.
[0003]
As shown in FIG. 8, the compacting pile forming apparatus 1 includes a casing pipe 2 arranged in a vertical direction with respect to a construction machine main body (not shown), a vibrator 3 that vibrates the casing pipe 2, and a casing pipe 2. And a piston cylinder mechanism 5 for reciprocating the compacting member 4 in the vertical direction.
[0004]
Next, sand pile creation work using this compacted pile creation device 1 will be described. The vibrator 3 is operated to penetrate the casing pipe 2 to a predetermined depth in the ground 6. Next, a pulling process is performed in which sand is discharged from the lower end of the casing pipe 2 while reciprocating the piston cylinder mechanism 5 and the casing pipe 2 is pulled upward by a predetermined length while being compacted. By this drawing process, the space in the ground 6 from which the casing pipe 2 is drawn is filled with sand.
[0005]
Next, raising and lowering is stopped and sand is supplied into the casing pipe 2. And the process of pulling the casing pipe 2 upward again is performed. Sand is discharged and compacted while reciprocating the piston cylinder mechanism 5 during this pulling process. Thereafter, when compaction is performed in the drawing process until reaching the ground surface, a sand pile 7 as shown in FIG. 9 is formed at a position where the casing pipe 2 is penetrated. Such sand piles 7 are formed at appropriate intervals in the improved area.
[0006]
By the way, it is general that the strength of the original ground 6 to be improved is not uniform and varies. Therefore, the present applicant has previously proposed a method for changing either one or both of the pile diameter and strength of the sand pile 7 to be created according to the strength of the original ground 6 (Patent Document 1, Patent Document 2, Patent). Reference 3).
[0007]
For example, in the case where only the pile diameter is changed, this construction method will be described. In the compaction process, the piston cylinder mechanism 5 detects a pressing force pressing the sand pile 7 downward, and this pressing force reaches a predetermined installation value. Until the sand pile 7 is pressed. In the place where the original ground 6 is soft, the pressing force reaches a predetermined set value only when the sand pile 7 is greatly compressed and deformed in the direction of expanding the diameter, and the sand pile 7 having a large diameter is formed.
[0008]
Moreover, in the place where the original ground 6 is hard, the sand pile 7 does not expand so much, the pressing force reaches a predetermined set value, and the sand pile 7 having a relatively small diameter is formed. In this way, in the compaction process, the sand pile 7 with a constant pressing force of the piston cylinder mechanism 5 is created to reinforce the ground according to the softness of the original ground, thereby achieving a uniform ground improvement. Is.
[0009]
[Patent Document 1]
Japanese Patent Publication No. 61-25859 [0010]
[Patent Document 2]
Japanese Patent Publication No. 64-2725
[Patent Document 3]
US Pat. No. 4,487,524
[Problems to be solved by the invention]
However, in the conventional compacted pile construction method, if the original ground 6 is very soft, the diameter of the sand pile 7 becomes too large until the pressing force of the piston cylinder mechanism 5 reaches a predetermined set value. A large-diameter sand pile 8 as shown on the left side of FIG. 10 is formed. In the worst case, the pressing force of the piston / cylinder mechanism 5 does not reach a predetermined set value, and the operation is temporarily stopped. From the above, total construction time and total sand volume increased, and these increases led to an increase in construction costs.
[0013]
In particular, there was a high possibility that the above-described problems would occur in places where no sand piles 7 were formed around the beginning of the construction start.
[0014]
Therefore, the present invention has been made to solve the above-described problems, and a sand pile having a strength that does not cause any inconvenience in strength even when the original ground is very soft, and the total The object is to provide a compacted pile construction method that can reliably suppress the increase in construction time and total sand volume.
[0015]
[Means for Solving the Problems]
The invention according to claim 1 is a drawing step of drawing out the casing pipe while discharging the granular material from a lower end of the casing pipe after an initial penetration step of penetrating the casing pipe to a predetermined depth in the ground. In the compacted pile construction method in which a pile of granular material is formed in the ground by alternately repeating a compacting process of compacting the granular material discharged through re-penetration, in the compacting process, the casing pipe is powdered Always calculate the compaction force when compacting the granule and the pile cross-sectional area of the powder compacted by the casing pipe, and the pile cross-sectional area of the granular material is minimized by compacting the casing pipe When the compaction force reaches a predetermined set value before reaching the pile cross-sectional area, the compaction is completed when the pile cross-sectional area of the granular material reaches the minimum pile cross-sectional area, -If the compaction force reaches a preset value before the pile cross-sectional area of the granular material reaches the maximum pile cross-sectional area due to compaction of the singing pipe, the compaction is performed when the compaction force reaches the preset value. If the pile cross-sectional area of the granular material due to the compaction of the casing pipe reaches the maximum pile cross-sectional area before the compaction force reaches the predetermined set value, the pile cross-sectional area of the granular material is the maximum Compaction is completed when the pile cross-sectional area is reached.
[0016]
In this compacted pile construction method, the pile cross-sectional area does not exceed the maximum cross-sectional area even if the original ground is very soft, and the pile is not required to be compacted with the predetermined set-up force. Since the diameter has the maximum cross-sectional area, the necessary minimum strength is maintained. Therefore, a sand pile that does not cause any inconvenience in strength even when the original ground is very soft is created, and an increase in the total construction time and the total amount of sand is surely suppressed.
[0017]
Invention of Claim 2 is the compaction pile construction method of Claim 1, Comprising: In the said compaction process, while pressing the said casing pipe below and rotating the said casing pipe, the pile of a granular material is tightened The compaction force is characterized by a pressing force by which the casing pipe presses the powder pile and a rotational torque by which the casing pipe rotates with respect to the powder pile. .
[0018]
In this compacted pile construction method, in addition to the operation of the invention of claim 1, since the information in accordance with the compacted state, that is, the strength of the pile is obtained, a pile having a desired strength is created.
[0019]
Invention of Claim 3 is the compaction pile construction method of Claim 2, Comprising: The pressing force of the said casing pipe is P, The rotational torque of the casing pipe at the time of the said drawing process is T1, The casing at the time of the said compacting process Assuming that the rotational torque of the pipe is T2, the compaction time is t, and the coefficients obtained from the construction data are α and β, the compaction force F is calculated by the formula F = α · P · (T2 / T1) · t + β. It is characterized by having a value.
[0020]
In this compaction pile construction method, in addition to the effect of the invention of claim 2, since the relative rotational torque ratio between the immediately preceding drawing process and the subsequent compacting process is used as the rotational torque component, the difference in the depth of the ground The magnitude of the rotational torque excluding the friction resistance of the casing pipe due to the above becomes an element of the compaction force. Therefore, the compacted state, that is, the strength of the pile is grasped more accurately, and as a result, a pile having a desired strength is formed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0022]
1 to 6 show an embodiment of the present invention, FIG. 1 is a side view of a compacted pile building device, FIG. 2 (a) is a front view of a rotating mechanism, and FIG. 2 (b) is FIG. 2 (a). 3 is a cross-sectional view taken along the line AA, FIG. 3 is a main circuit block diagram of the control system of the compacted pile forming device, FIG. 4 is a flowchart at the time of compacted pile construction, and FIG. 5 illustrates the compacted pile creating method. Process drawing, FIG. 6 is a figure which shows the minimum pile diameter and maximum pile diameter of a creation pile.
[0023]
As shown in FIG. 1, the compacted pile forming apparatus 10 has a leader 12 on the front surface of the construction machine main body 11, and the leader 12 is erected in a vertical direction at a position above the surface of the ground 6. A casing pipe 13 is arranged on the reader 12 so as to be movable up and down along the vertical direction.
[0024]
The casing pipe 13 has a cylindrical shape, and a hopper 14 is provided on the upper end side thereof. The sand 15 which is a granular material can be put into the casing pipe 13 from the hopper 14. The casing pipe 13 is provided with a sand surface sensor 16 (shown only in FIG. 3) for detecting the sand surface position of the sand 15 (shown only in FIG. 5) accumulated in the casing pipe 13.
[0025]
The elevating mechanism 17 includes an elevating motor (not shown) and power transmission means (not shown) that transmits the rotational force of the elevating motor to the casing pipe 13, and moves the casing pipe 13 up and down in the ground 6. Further, the elevating mechanism 17 is provided with a hydraulic pressure sensor 18 that detects the hydraulic pressure during the elevating operation of the casing pipe 13. Further, the elevating mechanism 17 is provided with a depth meter 19 that detects the depth of the lower end of the casing pipe 13.
[0026]
As shown in FIGS. 2A and 2B, the rotation mechanism 20 includes a pair of left and right rotation motors 21, 21, a first gear 22 fixed to the rotation shaft of each motor 21, and each of the first gears 22. The first gear 22 meshes with the second gear 23 fixed coaxially on the outer periphery of the casing pipe 13, and the casing pipe 13 is rotated in a certain direction. The rotation mechanism 20 is provided with a current sensor 24 that detects the current value of the rotation motor 21.
[0027]
As shown in FIG. 2A, the swivel joint 25 is provided in the casing pipe 13 below the rotation mechanism 20, and the air pipe 26 is connected via the swivel joint 25. An air compressor (not shown) is connected to the other end of the air pipe 26 so that pressurized air can be supplied to the casing pipe 13 through the air pipe 26.
[0028]
Next, a control system of the compacted pile building device 10 will be described. As shown in FIG. 3, the detection outputs of the sand surface sensor 16, the hydraulic sensor 18, the depth meter 19, and the current sensor 24 are input to the control unit 25, and the control unit 27 rotates the lifting mechanism 17 and the rotation based on these information and the like. The mechanism 20, the air compressor, and the like are controlled. Since the hydraulic pressure value detected by the hydraulic sensor 18 is proportional to the pressing force (reaction force from the sand pile 30) that presses the sand pile 30 at the lower end 13a of the casing pipe 13, the control unit 27 determines the hydraulic pressure value of the hydraulic sensor 18. More pressing force is obtained by calculation. Since the current value detected by the current sensor 24 is proportional to the rotational load of the casing pipe 13, the control unit 27 obtains the rotational torque of the casing pipe 13 by calculation from the current value of the current sensor 24.
[0029]
In addition, the detection information of various sensors is displayed on the instrument panel 28 provided at the driver's seat position of the construction machine main body 11 by the control unit 27. The driver can grasp and monitor the state of the compacting work from the instrument panel 28.
[0030]
Next, the compaction pile creation work by the compaction pile creation device 10 will be described based on the flow of FIG. 4 and the explanatory diagram of FIG.
[0031]
First, as shown in the state of (1) in FIG. 5, the compacted pile forming apparatus 10 is moved to a desired construction position, and sand 15 is put into the standing casing pipe 13 from the hopper 14. Next, as shown in the state of (2) in FIG. 5, an initial penetration process is started in which the elevating mechanism 17 and the rotating mechanism 20 are driven to lower the casing pipe 13 while rotating into the ground 6 (step S1). . The depth meter 19 constantly checks whether or not the lower end 13a of the casing pipe 13 has reached a predetermined depth L (step S2). As shown in the state of (3) in FIG. 5, the lower end 13a of the casing pipe 13 is When the predetermined depth L is reached, the initial penetration process is terminated (step S3).
[0032]
Next, as shown in the state of (4) in FIG. 5, the inside of the casing pipe 13 is pressurized with pressurized air, and the casing pipe 13 is discharged by a predetermined length L1 while the sand 15 is discharged from the lower end 13a of the casing pipe 13. A drawing process for drawing is started (step S4). The depth meter 19 constantly checks whether or not the casing pipe 13 has been pulled out by a predetermined pulling amount L1 (step S5). When the casing pipe 13 is pulled out by a predetermined length L1, the pressurized air in the casing pipe 13 is removed. The extraction and extraction process is terminated (step S6). By this drawing process, the sand 15 is filled in the space in the ground 6 from which the casing pipe 13 is drawn.
[0033]
Next, as shown in the state of (5) in FIG. 5, a compacting process for re-penetrating is started by driving the elevating mechanism 17 and the rotating mechanism 20 to lower the casing pipe 13 while rotating (step S7). ). In the compaction step, whether (step S8) compaction force F by the casing pipe 13 is a predetermined set value F ₀ or more, when the compaction force F becomes the set value F ₀ or Sunakui径minimum D value whether reaches D1 above (step S9), and if the compaction force F is less than the set value F ₀ Sunakui径D it is checked whether or not reached the maximum value D2 (step S10).
[0034]
Here, the tightening force F is the pressing force of the casing pipe 13 as P, the rotational torque of the casing pipe 13 during the drawing process as T1, the rotational torque of the casing pipe 13 during the compacting process as T2, the compaction time as t, Assuming that the coefficients obtained from the construction data are α and β, the values are calculated by the equation F = α · P · (T2 / T1) · t + β.
[0035]
The pressing force P is calculated by multiplying the hydraulic value of the hydraulic sensor 18 by a predetermined coefficient, and the rotational torques T1 and T2 are calculated by multiplying the current value of the current sensor 24 by a predetermined coefficient. The minimum sand pile diameter D1 and the maximum sand pile diameter D2 are constructed with a fixed pile diameter, and the pressing force and preliminary boring data are compared for each soil layer, and determined with reference to past construction data. The sand pile diameter D is calculated by calculating the amount of sand discharged into the ground 6 by detecting the height difference between the sand surface position before the previous drawing process and the sand surface position after the drawing process from the sand surface sensor 16. The amount of sand and the compaction stroke S in the compaction process are calculated.
[0036]
And as shown in FIG. 6, before the pile diameter (pile cross-sectional area) of the sand pile 30 reaches the minimum pile diameter (minimum cross-sectional area) D1 by the compaction of the casing pipe 13, the compacting force F is a predetermined set value. when it reaches the F ₀ complete compaction when the pile diameter D of Sunakui 30 reaches the minimum pile diameter D1 (step S11). Compaction force F in the case of the compaction force F before the pile diameter D of the sand pile 30 reaches the maximum pile diameter (maximum pile cross-sectional area) D2 by compaction of casing pipe 13 reaches a predetermined set value F ₀ There completing the compaction at the time of reaching a predetermined set value F ₀ (step S11). Further, when the compaction force F is pile diameter D of Sunakui 30 by compaction of the casing pipe 13 before reaching the predetermined set value F ₀ is at the maximum pile diameter D2 is the Sunakui 30 pile diameter D When the maximum pile diameter D2 is reached, compaction is completed (step S11).
[0037]
Thereafter, the above-described drawing process and compacting process of the casing pipe 13 are repeated alternately. If the sand 15 in the casing pipe 13 decreases in these repeated processes, the air in the casing pipe 13 is extracted at that time and the sand 15 is replenished. And as shown to the state of (6) of FIG. 5, it complete | finishes when the depth of the lower end 13a of the casing pipe 13 reaches zero (step S12). Then, the sand pile 30 is created in the position where the casing pipe 13 is initially penetrated. The pile diameter D of the sand pile 30 to be created is in the range of D1 ≦ D ≦ D2.
[0038]
As described above, according to this compacted pile construction method, the pile diameter (pile cross-sectional area) of the sand pile 30 may exceed the maximum pile diameter (maximum cross-sectional area) D2 even if the raw ground 6 is a very soft spot. In addition, even if the pile diameter 30 is not compacted by a compaction force of a predetermined set value, the minimum necessary strength is maintained because the pile diameter 30 has the maximum pile diameter (maximum cross-sectional area) D2. Therefore, even if the original ground 6 is a very soft part, the sand pile 30 of the grade which does not generate | occur | produce an intensity | strength does not generate | occur | produce, and the increase in total construction time and total sand amount can be suppressed as much as possible. . In addition, even if the base ground 6 is very hard, the pile diameter (cross-sectional area) D of the sand pile 30 is not smaller than the minimum pile diameter (minimum cross-sectional area) D1, and the minimum necessary pile diameter (cut-off) Area) sand pile 30 is created.
[0039]
In the compacting process of the embodiment, the casing pipe 13 is pressed downward and the casing pipe 13 is rotated to compact the sand 15, and the compacting force F is a pressing force P at which the casing pipe 13 presses the sand 15. And the rotational torque T (= T2 / T1) at which the casing pipe 13 rotates with respect to the sand 13 is an element. In other words, when the columnar sand 15 is compacted, the pressing force P and the rotational torque T (= T2 / T1) are more reliably compacted than when only the pressing force P is applied from the casing pipe 13. . Accordingly, in order to grasp the compacted state of the sand 15, that is, the strength, the external force having the pressing force P and the rotational torque T (= T2 / T1) as elements is used as the compacting force, that is, the compacted state is accurate. The strength of the sand pile 30 can be grasped, and as a result, the sand pile 30 having a desired strength can be created.
[0040]
In the above embodiment, the pressing force of the casing pipe 13 is P, the rotational torque of the casing pipe 13 during the drawing process is T1, the rotational torque of the casing pipe 13 during the compacting process is T2, the compaction time is t, and the construction data When the obtained coefficients are α and β, the compaction force F is a value calculated by the equation F = α · P · (T2 / T1) · t + β. Accordingly, since the relative rotational torque ratio (T2 / T1) between the immediately preceding drawing process and the subsequent compacting process is used as the component of the rotational torque T, the friction resistance of the casing pipe 13 due to the difference in the depth of the ground 6 is excluded. The magnitude of the rotating torque T can be used as an element of compaction force. Therefore, the compacted state, that is, the strength of the sand pile 30 can be grasped more accurately, and as a result, the sand pile 30 having a desired strength can be created.
[0041]
FIG. 7 is a perspective view of a main part of a modification of the rotating mechanism. Although the rotating mechanism 20 of the above embodiment continuously rotates the casing pipe 13 in a fixed direction, the rotating mechanism (swinging mechanism) 31 of this modified example reciprocates alternately in the forward direction and the reverse direction. It is something to be made. That is, as shown in FIG. 7, the rotation mechanism (swing mechanism) 31 has a pair of hydraulic cylinder mechanisms 32, 32, and the tip of each piston rod 32 a of the pair of cylinder mechanisms 32, 32 is the casing pipe 13. Are connected to each connecting arm 33 projecting from a position facing substantially 180 degrees on the outer periphery of the outer periphery of the outer periphery of the outer periphery via a support pin 34.
[0042]
The pair of hydraulic cylinder mechanisms 32, 32 alternately advance and retreat their piston rods 32a, whereby the casing pipe 13 is alternately reciprocated in the forward direction and the reverse direction.
[0043]
Even when the rotation mechanism 31 of the modified example is applied to the compacting method of the present invention, the same operation and effect as in the above embodiment can be obtained. And since an air pipe etc. can be connected with casing pipe 13 without interposing swivel joint 25 compared with rotation mechanism 20 of the above-mentioned embodiment, there is an advantage that the mechanism of compaction pile creation device 10 becomes simple as a whole. .
[0044]
Moreover, as a compaction pile construction method, the sand pile 30 is replenished between the 1st stage which creates the sand pile 30 with a rough space | interval in the area which wants to improve ground, and the sand pile 30 with a rough space after this 1st stage. There is a two-step creation process in which the sand piles 30 are finally created by being divided into the second stage. In this construction method, the sand pile 30 to be created in the first stage does not always have to have a predetermined set strength, and it can be considered that there is only a certain level of strength. Therefore, the compacting construction method of the present invention is the first construction method. It can be said that the construction method is particularly excellent for the construction of the sand pile 30 on the stage. However, it is needless to say that the present invention can be applied to a construction method in which the sand piles 30 are sequentially formed at a close interval from the beginning.
[0045]
In addition, in the said embodiment, since the casing pipe 13 is cylindrical shape, it changes into the cross-sectional area of the sand pile 30, and uses a diameter dimension, and the sand pile diameter D is more than the minimum sand diameter D1 or more than the maximum sand diameter D2. It was determined. However, the case where the casing pipe 13 has a shape other than the cylindrical shape is also conceivable. In that case, the size of the sand pile 30 is controlled using the cross-sectional area. However, when the casing pipe 13 has a shape other than the cylindrical shape, it is difficult to rotate the casing pipe 13, so the sand pile 30 is compacted only by the pressing force P without rotating the casing pipe 13. . In this case, the compaction force F includes only the pressing force P not including the rotational torque T as an element.
[0046]
Moreover, in the said embodiment, although the sand 15 was used as a granular material which is a pile material, as a pile material, it is not restricted to the sand 15, Sand-like granular materials, solidification materials, such as gravel and a crushed stone, sand 15, gravel, etc. Of course, a mixture thereof including, for example, a mixture of crushed stone and iron powder may be used.
[0047]
【The invention's effect】
As described above, according to the invention of claim 1, in the compaction step, the compaction force when the casing pipe compacts the granular material and the pile breakage of the granular material compacted by the casing pipe. If the compaction force reaches a set value before the pile cross-sectional area of the granular material reaches the minimum pile cross-sectional area due to compaction of the casing pipe, the pile cross-sectional area of the granular material is calculated. When the minimum pile cross-sectional area is reached, the compaction is completed, and the compaction force reaches the set value before the pile cross-sectional area of the granular material reaches the maximum pile cross-sectional area due to the casing pipe compaction. When the compaction force reaches the specified set value, the compaction is completed, and before the compaction force reaches the specified set value, the pile cross-sectional area of the granular material due to compaction of the casing pipe is the maximum pile breakage. When the area is reached, the pile breaks Completing the compaction when the product has reached the maximum pile cross-sectional area. Since this compaction pile construction method is used, the pile cross-sectional area does not exceed the maximum cross-sectional area even if the ground is very soft, and the compaction force is set with a predetermined set value. Even if not, the minimum necessary strength is maintained because the pile diameter has the maximum cross-sectional area. Accordingly, it is possible to create a sand pile that does not cause any inconvenience in strength even if the original ground is very soft, and to reliably suppress an increase in total construction time and total sand amount.
[0048]
According to the invention of claim 2, in the compacting step, the casing pipe is pressed downward and the casing pipe is rotated to compact the pile of the granular material. Since the pressing force that presses and the rotational torque that the casing pipe rotates with respect to the pile of granular material is an element, it is possible to obtain information that is accurately compacted, that is, the strength of the pile, A pile having a desired strength can be created. That is, when the columnar powder is compacted, it is more reliably compacted when both the pressing force and the rotational force are applied than when only the pressing force is applied from the casing pipe. Therefore, in order to grasp the compacted state of the granular material, that is, the strength of the pile, more accurate information can be obtained if the external force with the pressing force and the rotational torque as elements is used as the compacting force.
[0049]
According to the invention of claim 3, the pressing force of the casing pipe is P, the rotational torque of the casing pipe during the drawing process is T1, the rotational torque of the casing pipe during the compacting process is T2, the compaction time is t, and the construction data Assuming that the coefficients obtained are α and β, the compaction force F is a value calculated by the equation F = α · P · (T2 / T1) · t + β. And a relative rotational torque ratio between the subsequent compaction process and the magnitude of the rotational torque excluding the friction resistance of the casing pipe due to the difference in the depth of the ground can be used as an element of the compaction force. Therefore, the compacted state, that is, the strength of the pile can be grasped more accurately, and as a result, a pile having a desired strength can be created.
[Brief description of the drawings]
FIG. 1 is a side view of a compaction pile forming apparatus according to an embodiment of the present invention.
2A and 2B show an embodiment of the present invention, in which FIG. 2A is a front view of a rotating mechanism, and FIG. 2B is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a main part circuit block diagram of a control system of the compaction pile forming apparatus according to the embodiment of the present invention.
FIG. 4 is a flowchart at the time of compaction pile construction showing an embodiment of the present invention.
FIG. 5 is a process diagram illustrating a compacted pile construction method according to an embodiment of the present invention.
FIG. 6 is a diagram showing a minimum pile diameter and a maximum pile diameter of a constructed pile according to an embodiment of the present invention.
FIG. 7 is a perspective view of a main part of a modification of the rotation mechanism.
FIG. 8 is a configuration diagram of a main part of a conventional compaction pile forming apparatus.
FIG. 9 is a cross-sectional view showing a sand pile created in the ground.
FIG. 10 is a cross-sectional view showing a sand pile formed on a very soft ground and a sand pile having a substantially standard diameter.
[Explanation of symbols]
10 Compaction pile creation device 13 Casing pipe 13a Lower end 15 Sand (powder)
30 Sand pile (pile of granular material)

Claims (3)

After the initial penetration step of penetrating the casing pipe to a predetermined depth in the ground, a drawing step of pulling out the casing pipe while discharging powder particles from the lower end of the casing pipe, and powder discharged by re-penetrating the casing pipe In the compacted pile construction method of creating a pile of granular material in the ground by alternately repeating the compacting process of compacting the granular material,
In the compacting step, the compaction force when the casing pipe compacts the granular material and the pile cross-sectional area of the granular material compacted by the casing pipe are always calculated, and the casing pipe is compacted. If the compaction force reaches the set value before the pile cross-sectional area of the granular material reaches the minimum pile cross-sectional area due to compaction, tightening will be performed when the pile cross-sectional area of the granular material reaches the minimum pile cross-sectional area. When the compaction force reaches a predetermined set value before the pile cross-sectional area of the granular material reaches the maximum pile cross-sectional area by compaction of the casing pipe by compaction of the casing pipe, the compaction force is a predetermined set value. If the pile cross-sectional area of the granular material due to compaction of the casing pipe reaches the maximum pile cross-sectional area before the compaction force reaches a predetermined set value, The pile cross-sectional area of the body reaches the maximum pile cross-sectional area Compaction pile reclamation method, characterized in that to complete the compaction at the. The compacted pile construction method according to claim 1,
In the compaction step, the casing pipe is pressed downward and the casing pipe is rotated to compact the powder pile. The compaction force is a pressure that the casing pipe presses the powder pile. A compacted pile construction method characterized by having pressure and rotational torque that the casing pipe rotates with respect to the pile of granular materials as elements. The compacted pile construction method according to claim 2,
The pressing force of the casing pipe is P, the rotational torque of the casing pipe at the time of the drawing process is T1, the rotational torque of the casing pipe at the time of the compacting process is T2, the compaction time is t, and the coefficient obtained from the construction data is α , Β, the compaction force F is a value calculated by the formula F = α · P · (T2 / T1) · t + β.

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