JP4200237B2 - Construction method of foundation pile - Google Patents

Description

  The present invention is a method for constructing a foundation pile by burying a ready-made pile in a pile hole, which mainly reduces the amount of soil discharged from industrial waste, and is used for solidifying agents such as cement milk used for the foundation pile construction. The present invention relates to a method for constructing a foundation pile for the purpose of reducing usage and saving.

  As a foundation structure such as a building, a pile foundation in which a ready-made pile is buried in a pile hole is frequently used. In this case, a soil cement layer was formed by injecting a solidifying agent such as cement milk into the root-fixing portion of the pile hole in order to increase the supporting force of the ready-made pile. This reinforces the ground of the pile hole to stabilize the supporting force and enhances the proof strength against vertical loads.

  In this case, cement milk was filled to the vicinity of the upper end of the pile hole in order to increase the bearing capacity, so when burying the ready-made pile, excavation mud or soil that contained a solidifying agent in an amount equivalent to the volume of the ready-made pile Soil cement overflowed from the pile hole and was discharged.

  Therefore, the drilling mud discharged from the pile hole is conventionally handled as follows.

(1) The drilling mud is sucked into a vacuum car as industrial waste, and is carried out from the construction site. In this case, there is a problem that not only the construction management becomes troublesome, but also the discharge work becomes large and the transportation cost increases.

(2) Cement is further added to the drilling mud mixed with the solidifying agent to increase the solidification strength of the drilling mud, and backfilled to the vacant ground surface at the construction site. This treatment method is limited to a site having a large excess of land where the drilling mud can be backfilled, and the construction site cannot be adopted narrowly in urban areas.

(3) At the construction site, the excavated muddy water discharged was treated and backfilled in the hollows of the pile holes or ready-made piles. This method generally requires a special treatment for reducing the volume of dewatered drilling mud and the like, resulting in an increase in cost.

(4) Moreover, in the ready-made pile, the construction method which reduces the excavation soil by screwing into the predetermined ground by using the structure of the ready-made pile as a steel pipe pile with a spiral wing is proposed (Patent Document 1).
The method of screwing and embedding steel pipe piles with spiral wings is a general concrete ready-made pile that has a limited construction ground and is limited to soil with a small bearing capacity, and exhibits a high bearing capacity on a relatively good ground. Was not available and was not versatile.

(5) Moreover, the construction method which eliminated the generation | occurrence | production of the residual soil using the ready-made pile formed so that an outer diameter may reduce from a cylindrical part to a front-end | tip part is proposed (patent document 2). In this construction method, the volume of the cylindrical part is configured to be larger than the tip part, and by inserting this ready-made pile, the surrounding soil is consolidated and the volume of earth and sand taken into the ready-made pile is reduced. Furthermore, the excavated soil was backfilled in the hollow part of the cylindrical part. This method has a problem in that it requires a large-scale device for consolidating the ground and burying ready-made piles.

(6) Also, in the field of ground improvement, excavate the so-called bad ground to be improved, and mix the excavated soil with a solidifying agent such as cement milk to create a soil cement column. Construction method is made. The purpose was to modify and create a predetermined ground strength with soil cement columns.
At this time, a method of excavating first and excavating the excavated soil partially in accordance with the injection of a solidifying agent such as cement milk has also been made. On the other hand, in the foundation pile, it is necessary to maintain the shape and dimension of the pile hole when excavating the pile hole, and further, it is necessary to transmit the frictional force and the like with the surrounding ground. Therefore, this method for ground improvement could not be applied to the creation of high quality pile holes.
In other words, foundation piles need to be excavated not only in poor ground but also in various soils and strengths. In the excavation, a pile hole having a desired inner wall is formed with a predetermined shape and size designed. It was. Also, the cement milk layer that maintains the shape and dimensions of the pile hole and adopts various mixing methods, agitation methods, etc. in the pile hole according to the supporting force required for each depth, etc., and having different solidification strength The soil cement layer was formed. Furthermore, in the foundation pile structure, it is necessary to smoothly lay the ready-made pile in the created pile hole, and as the constructed foundation pile, it is integrated with the surrounding ground to give a predetermined support force to the foundation pile. It was a construction method. Therefore, the foundation pile structure is completely different from the ground improvement method in which ground is simply excavated and solidified with the excavated soil to create a ground with a predetermined ground strength or more.
Japanese Utility Model Publication 4-31317 JP 9-49229 A

  Since the conventional technique has the above-mentioned problems, the present application has been invented for the following purposes as well as solving the problem.

(1) Significantly reduce the discharge of industrial waste (drilling mud) containing solidifying agents used in the construction of pile foundations in various grounds.
(2) Excavated soil discharged from pile foundation construction is classified as general residual soil and discharged.
(3) Do not mix the solidifying agent in the excavated soil, and save the amount of solidifying agent used.
(4) In general, improve the soil quality of the upper layer of soft construction sites with low bearing capacity, reinforce the pile surrounding ground in the upper layer of the pile hole, and improve the horizontal strength.
(5) The excavation rod directly above the excavation head facilitates the discharge of excavation soil above the pile hole and improves the excavation efficiency in the deep layer.

  However, according to the present invention, before the solidifying agent is charged and mixed, a predetermined amount of excavated soil (for example, excavated soil corresponding to the amount of the solidifying agent input, etc.) is discharged after excavating the excavated soil in the upper layer such as the ground surface. The problem was solved because the piles were buried.

That the present invention, the root compaction portion of Kuiana were drilled, by introducing a solidifying agent to form roots hardened layer, to the root consolidated layer, prefabricated pile linked alone or profiles pile hollow profiled piles Is a foundation pile construction method in which a pile circumference is formed above the root consolidation part of the pile hole, and a pile circumference fixing liquid layer is formed from the injected solidifying agent. “ This is a foundation pile construction method characterized by taking the following steps.
(1) Divide the solidification agent injection amount W1 to be poured into the root consolidation part by the pile hole cross-sectional area in advance to set an equivalent excavation length A, and set the solidification agent injection amount W2 to be introduced into the pile peripheral part. The equivalent excavation length B is set by dividing by the pile hole cross-sectional area, the volume excluding the volume of the hollow portion of the ready-made pile is taken as the actual volume, and the actual volume is divided by the cross-sectional area of the pile hole to obtain the equivalent excavation length. Set C.
(2) An excavating blade having a length L corresponding to the amount of earth excavated is formed above the excavating blade, and a kneading drum is mounted on the excavating means without providing an excavating means, and excavating. Configure the rod.
(3) in the drill rod, the Kuiana upper portion from the ground surface, the corresponding drilling length A, and the corresponding equivalent drilling length B and the corresponding drilled length C drilling on the earth surface side of the excavated soil To discharge. The discharged excavated soil is treated as general residual soil.
(4) Subsequently, the pile hole is excavated to a predetermined depth, a solidifying agent is injected into the pile hole, and "replaced with the remaining excavated soil" and / or "stirred and mixed with the remaining excavated soil" are mixed. ”To form a root consolidation layer and to form a pile circumference fixing liquid layer above the root consolidation layer .
(5) Subsequently, the ready-made pile is sunk in the pile hole, and the upper surface of the pile fixing liquid layer is placed in the pile hole, and the excavated soil mixed with the solidifying agent is not discharged to the ground.

Further, another aspect of the present invention, the root compaction portion of Kuiana were drilled, by introducing a solidifying agent to form roots hardened layer, to the root consolidated layer was ligated alone or profiles pile hollow profiled piles A method for constructing a foundation pile in which a foundation pile is constructed by burying a ready-made pile , wherein a pile periphery is formed above the root consolidation part of the pile hole, and a pile periphery fixed liquid layer is formed from the injected solidifying agent In addition, “ It is a foundation pile construction method characterized by taking the following steps.
(1) The amount of solidification agent injected into the root consolidation part is divided by the pile hole cross-sectional area in advance to set an equivalent excavation length A, and the amount of solidification agent injection W2 injected into the pile periphery fixing part. Is divided by the pile hole cross-sectional area to set the equivalent excavation length B, the volume excluding the volume of the hollow portion of the ready-made pile is taken as the actual volume, and the actual volume is divided by the pile hole cross-sectional area to obtain the equivalent excavation length Set C.
(2) An excavating blade having a length L corresponding to the amount of earth excavated is formed above the excavating blade, and a kneading drum is mounted on the excavating means without providing an excavating means, and excavating. Configure the rod.
(3) in the drill rod, the Kuiana upper portion from the ground surface, the corresponding drilling length A, and the corresponding equivalent drilling length B and the corresponding drilled length C drilling on the earth surface side of the excavated soil To discharge. The discharged excavated soil is treated as general residual soil.
(4) Subsequently, the pile hole is excavated to a predetermined depth, a solidifying agent is injected into the pile hole, and "replaced with the remaining excavated soil" and / or "stirred and mixed with the remaining excavated soil" are mixed. ”To form a root consolidation layer and to form a pile circumference fixing liquid layer above the root consolidation layer .

  In addition, in the above, after discharging the “predetermined amount of excavated soil” to the ground or before discharging, a casing having a length corresponding to the amount of excavated soil discharged is inserted into the hole of the pile, It is a construction method of a foundation pile characterized by excavation.

  Further, in the above, after discharging the “predetermined amount of excavated soil” to the ground or before discharging, the pile hole excavation is performed with the water filled up to the pile hole mouth. is there.

  In addition, in the above-mentioned foundation pile structure in which a ready-made pile is designed with standard values of a predetermined diameter and depth of a pile hole, a predetermined outer diameter, an inner diameter and a length based on a necessary supporting force, The diameter is larger than the standard value ”and / or“ the inner diameter of the ready-made pile is smaller than the standard value ”, the actual volume of the ready-made pile is set larger than the standard value, and the volume of the pile hole is It is a construction method for a foundation pile characterized in that it is embedded in combination with a ready-made pile having a relatively large actual volume, and the amount of solidifying agent used is relatively reduced.

  Furthermore, in the above, the ground around the pile hole mouth of the pile hole is excavated at a predetermined depth with “1.5 times the diameter of the pile hole diameter” to “a diameter not interfering with the adjacent pile hole”. It is the construction method of the foundation pile which forms an accommodating part.

  The solidifying agent in the above refers mainly to cement milk, but can be used if it is a hydraulic material that solidifies in the pile hole.

  Moreover, although the soil discharging means in the above mainly indicates a spiral rod, any member can be adopted as long as it is a conventional member capable of soil discharging.

Further, the length of the casing in the above “length corresponding to the amount of discharged excavated soil” refers to the volume of the excavated soil of “amount corresponding to the volume of the solidifying agent to be introduced” when discharged to the ground. This refers to the depth of the pile hole according to. For example, assuming that the cross-sectional area A (m ² ) of the pile hole and the input amount V (m ³ ) of the solidifying agent, the length L (m) of the casing = V ÷ A.

  In addition, in the above-mentioned housing portion, “diameter of 1.5 times the diameter of the pile hole” to “diameter in a range not interfering with the adjacent pile hole”, when 1.5 times or less, usually only a part of soil cement or the like is used. Since it is not accommodated, 1.5 times or more is preferable. In addition, the “diameter within the range not interfering with the adjacent pile hole” is usually formed by separating the adjacent pile hole by about 2.5 times the diameter of the pile hole. It is not preferable that the two come into contact with each other. In addition, the “predetermined depth” of the accommodating portion is selected and set according to the amount of excavated soil mixed with the solidifying agent to be processed, the thickness of the ground on the ground surface to be improved, and the like.

  The “predetermined amount of excavated soil” is set between “cement milk injection amount W” and “pile volume V and cement milk injection amount W”, and the soil soil properties of the ground and the method of creating the pile hole In particular, it refers to the amount and the like that are appropriately changed depending on the method and presence of kneading, the condition of the construction ground, and the like.

  In addition, “making the diameter larger than the standard value” in the above refers to making the outer diameter larger than the standard value, etc., although the outer diameter and inner diameter of the ready-made pile are determined as standard values.

(1) According to the present invention, the excavated soil corresponding to the volume of the solidifying agent to be injected or the ready-made pile to be used is discharged on the surface side “before injecting the solidifying agent” or “after injecting and before mixing”. In addition, after injecting the solidifying agent, some solidification agent mixed excavated soil such as the volume of the ready-made piles is discharged, so that there is an effect that it is possible to significantly reduce the industrial waste residue soil mainly composed of excavated soil.
In addition, by separating the drilling mud discharge time before and after the injection of the solidifying agent, the general residual soil (non-industrial waste) that is not mixed with the solidifying agent and the residual soil as mixed industrial waste are separated. Therefore, the amount of industrial waste discarded can be greatly reduced.

(2) In addition, since the excavated soil is discharged in advance from the ground surface where the ground strength is generally weak and there are many variations in strength, the solidifying agent layer (soil cement layer) around the pile is made into a higher quality and stronger layer. And the horizontal proof stress can be stabilized.
Here, if the solidification strength of the soil cement is made constant, the amount of cement milk to be injected can be similarly reduced.

(3) Also, if the excavation rod has a structure in which a soil removal means such as a spiral is provided directly above the excavation head and a spiral is not provided in the upper part of the excavation rod, a kneading means etc. are provided. , And the excavation speed at the excavation head is improved, the excavation speed is improved, and the soil cement variation is reduced even in the case of soil that contains viscous soil with poor excavability. be able to.

(4) In the present invention, the setting of the rotation speed N and the excavation speed v of the excavation rod is arbitrary, but considering the collapse property of the ground and excavation performance,
v / N ≦ L ₁ × n ₁ [Formula C]
v / N ≦ L ₂ × n ₂ [Formula D]
If the rotation speed N of the excavation rod and the excavation speed v are adjusted so that “v / N” is as small as possible, the pile hole wall is shaved a plurality of times at the same height. Since the kneading is done, it is possible to create a uniform and stronger high quality pile hole. Therefore, the pile hole wall can be prevented from collapsing or the risk of collapsing can be reduced, so that the formed solid support layer (soil cement layer) can be formed with high quality. Moreover, since the collapse of the pile hole wall can be prevented, the length of the casing to be installed to reinforce the pile hole wall at the pile hole opening can be made as short as possible, and furthermore, the casing itself can be made unnecessary by water injection of a predetermined amount.
Moreover, since the length of the casing is set to “the length according to the amount of excavated soil to be discharged”, the existing steel pipe can be diverted, and the casing can be easily procured, inserted and extracted, and is economical.

(5) In addition, if the present invention is applied, the pile head can be formed with water filled up to the pile hole mouth of the pile hole, so that the suspension for exposing the pile head of the foundation pile during the foundation base construction is exposed. Work can be reduced.

(6) Further, the present invention is not particularly limited in the type and structure of the ready-made pile to be used, but is particularly effective when a ready-made pile having a large gap between the outer surface of the ready-made pile to be used and the inner wall of the pile hole is used. .
For example, in the case of a deformed pile with a nodular or uneven projection provided on the outer surface of the shaft part of the ready-made pile, when excavating the pile hole, the maximum outer diameter of the ready-made pile (node or convex part) It is necessary to excavate a large-diameter pile hole as compared with the shaft diameter of the ready-made pile. Therefore, in this ready-made pile, the gap between the pile hole wall and the shaft outer peripheral surface of the ready-made pile may occur several times as compared with the case of a normal cylindrical pile, but the volume of the ready-made pile itself is The amount of the solidifying agent such as cement milk used is relatively small as compared with the diameter of the hole, and the amount of waste can be reduced accordingly.
Furthermore, here, as the ready-made pile, for example, by increasing the wall thickness and selecting and burying the ready-made pile having a relatively large pile hole actual volume compared to the pile hole volume, cement milk per foundation pile The amount of solidifying agent used can be saved. That is, it can be realized by increasing the outer diameter of the ready-made pile and / or decreasing the inner diameter, that is, by increasing the thickness and shape.
Therefore, according to this, “industrial waste mixed with solidifying agent” discharged to the ground can be reduced in the same manner, which is effective. That is, in the case of deformed piles such as ready-made piles with protrusions, if the excavated soil is discharged to the ground in advance by the amount of the solidifying agent to be injected, the effect of reducing “industrial waste mixed with the solidifying agent” becomes large.

(7) In addition, when forming the storage area around the pile hole mouth of the pile hole, excavated soil containing a solidifying agent such as cement milk overflowing from the pile hole can be stored in the storage area, and the original excavation is possible. The amount of discharged soil can be reduced, or the amount of solidifying agent such as cement milk can be increased. Furthermore, the ground on the ground surface side is strengthened by “excavated soil mixed with a solidifying agent” that is solidified in the accommodating portion.
Also, in this case, if the volume of the accommodating part matches the actual volume of the ready-made pile, even if only the excavated soil on the surface side according to the amount of solidifying agent such as cement milk is discharged, When the ready-made pile is sunk, the “excavated soil mixed with the solidifying agent” is accommodated in the accommodating portion and does not overflow to the ground. Therefore, “excavated soil mixed with solidifying agent” to be treated as industrial waste can be eliminated.

According to the design support force of the root consolidation part of the pile hole 5,
Ready-made pile 1 Length L ₁₀
Cross sectional area A ₁₀ (outer diameter D ₁₀ )
Actual volume (volume excluding hollow part) V
V = L ₁₀ × A ₁₀
Pile hole 5 Shaft cross-sectional area A ₁₁ (inner diameter D ₁ )
Depth H ₁₁
The total amount of cement milk (solidifying agent) injected is W
Set.
Assuming the injection amount W1 of the root-solidified portion and the injection amount W2 of the pile periphery fixing portion,
W = W1 + W2
It becomes.
Further, when the depth H ₁₂ of Kuiana 5 in accordance with the input amount of solidifying agent,
H ₁₂ = W ÷ A ₁₁
Further, the depth of the Kuiana 5 corresponding to the actual volume V of prefabricated pile 1 and H _10,
H ₁₀ = V ÷ A ₁₁
It becomes. The foundation pile structure 25 is constructed in the following procedure.

(1) from the ground 22 to a predetermined depth _{H 12,} and the pile hole drilling in the drilling head 16 of the drill rod 10, to discharge the excavated soil on the ground 22 (FIG. 3 (a). See FIG. 2 (a)) . Since the excavated soil to be discharged does not contain cement milk, the excavated soil is distinguished from industrial waste as general residual soil and can be treated as it is.
In general, the upper ground layer on the ground 22 side is soft and unfavorable when producing soil cement, and the ground 22 side excavated soil is easy to discharge, so the ground 22 side excavated soil is discharged.

(2) Then, to a predetermined depth _{H 11,} drilling Kuiana 5 (FIG. 3 (b), the Figure 2 (b)). At this time, the excavated soil is left in the pile hole 5, but can be appropriately discharged to the ground 22. In this case, since the cement milk is not yet injected, the excavated soil discharged can be treated as general residual soil.
In this state, the bottom side of the Kuiana 5, in which accumulated excavated soil S until _{H 17} (Figure 3 (b)). H ₁₇ is excavated soil other than H ₁₂ minutes excavated in (1) above.
Drilling until the depth H _12, also at any drilling depth H _11, during Kuiana excavation, carefully excavation while maintaining a predetermined shape and dimension Kuianakabe. Furthermore, it is necessary to secure a predetermined pile hole quality such as reinforcing and leveling the pile hole wall with a drilling rod.

(3) Next, a predetermined amount W1 of cement milk is injected at the bottom 8a of the root consolidation portion 6 of the pile hole 5, the excavated soil S is replaced with cement milk, or the mixture is stirred and mixed with cement milk. A hardened layer (solidified supporting force layer) 27 is formed (FIG. 3C). Depending on the required bearing capacity and the nature of the excavated soil, cement milk is injected at the root consolidation part 6 and mixed with the excavated soil to form a soil cement to form a root consolidation layer (solidified bearing capacity layer). You can also.

(4) Next, a predetermined amount W2 of cement milk is injected even above the consolidation layer and stirred and mixed with the excavated soil S to form a soil cement to form the pile fixing liquid layer 28, and the excavating rod 10 is Pull up to the ground 22 (FIG. 2 (c)). In this state, the pile peripheral fixed liquid layer (soil cement) 28 is usually filled up to the pile hole port 8 (FIG. 3D).

(5) Next, the ready-made pile 1 is buried in the pile hole 5. As the ready-made pile 1 descends, the actual volume of the ready-made pile 1 (volume excluding the hollow portion) V is
V = L ₁₀ × A ₁₀ = H ₁₀ × A ₁₁
The soil cement (excavated soil mixed with cement milk) overflows the ground 22 by a volume V of. With the ready-made pile 1 set in place, the pile circumference fixing liquid layer 28 is filled up to the pile hole 8 and the soil cement SC corresponding to the actual volume V overflows to the ground as a whole (FIG. 3 (e)). The overflow soil cement SC is treated as industrial waste.
After cement milk etc. solidify as mentioned above, foundation pile structure 25 is constituted (Drawing 3 (e) and Drawing 2 (d)).

(6) In the above, after discharging the excavated soil on the ground 22 side, before discharging, or while discharging, the steel tube casing 23 is inserted into the pile hole port 8 so that the surface side pile hole It is also possible to reliably prevent the wall from collapsing (FIG. 2 (b)).
Further, in order to prevent the pile hole wall from collapsing, the pile hole wall can be leveled by the kneading drum 13 of the excavating rod 10 during excavation. When the pile hole wall is particularly taken into consideration, the frictional support force of the ready-made pile 1 positioned in the pile circumferential fixed liquid layer is strengthened by the shaft portion 7 of the pile hole 5. Even in this case, at the site where the pile hole wall may collapse, the pile hole is filled with water or excavated soil in an amount corresponding to the amount of excavated soil discharged. Thus, the pile hole 5 can also be excavated.
Moreover, in the above, in the case of the foundation pile structure 25 which can ensure predetermined | prescribed support force only by the support force of a root hardening layer, a pile periphery fixed liquid layer can also be not formed. In this case, since the soil cement is not mixed in the excavated soil discharged to the ground 22 when the ready-made pile 1 is buried, the excavated soil can be distinguished and processed as general residual soil.

(7) Moreover, in the above, discharge of soil cement (excavated soil mixed with cement milk) can be completely eliminated (FIG. 4).
Drilling Kuiana discharges injection amount W of cement milk, the surface side of the excavated soil, which corresponds to the actual volume V of prefabricated pile 1 S (corresponding to the depth H ₁₄ of Kuiana) on the ground 22 (FIG. 4 (A)).
Subsequently, a predetermined depth to _{H 11,} drilling Kuiana 5 (Figure 4 (b)). In a state where the drilling Kuiana is completed, the Kuianasoko 8a side, excavated soil S depth H ₁₈ is left. still,
H ₁₈ = H ₁₁ −H ₁₄
It corresponds to.
Subsequently, cement milk having a total injection amount W (pile hole equivalent depth H ₁₂ ) is injected into the pile hole 5 (FIG. 4C).
The injected cement milk and excavated soil S are agitated and mixed to produce a soil cement SC, and a pile consolidation layer 27 is formed on the pile hole bottom 8a side, and a pile peripheral fixing liquid layer 28 is formed above the consolidation layer 27. (FIG. 4 (d)). In this state, a void 29 having a depth H ₁₀ corresponding to the actual volume V of the ready-made pile 1 is formed from the upper surface of the pile periphery fixing liquid layer 28 to the pile hole 8.
Subsequently, the ready-made pile 1 is set in the pile hole 5. Although the liquid level of the pile periphery fixed liquid layer 28 rises as it is laid, the upper surface of the pile periphery fixed liquid layer 28 is located near the pile hole 8 with the ready-made pile 1 set in place (FIG. 4 (e )), So there is no soil cement overflowing the ground 22 and discharged. After cement milk etc. solidify as mentioned above, foundation pile structure 25 is constituted (Drawing 4 (e)).
Here, if initially set to an amount smaller than the depth H ₁₄ the excavated soil S to be discharged on the ground, by cutting the ground around the mouth 8 of Kuiana 5, the housing portion 30 as the recess It can also be formed (FIG. 4 (d), dotted line 30). Housing section 30, for example, formed by 1.5 times the Kuiana径D _1, depth, and an amount corresponding to the first soil removing amount minute volume of less than H _14. In this case, the soil cement overflows from the pile hole 5 as much as the amount of soil is reduced, but no soil cement is accommodated in the accommodating portion 5 and discarded (FIG. 4 (f)).

  (8) In addition, the amount of discharge as general residual soil before mixing with cement milk is set appropriately depending on the soil quality of the ground, the method of creating the pile holes, the amount of soil that can be discharged according to the conditions of the construction ground, etc. It is desirable to set between “cement milk injection amount W” to “pile volume V and cement milk injection amount W” in view of construction management and quality stability.

  Embodiments of the present invention will be described with reference to the drawings.

[1] Construction specifications

Ready-made pile 1 BF pile
(Trademark of Mitani Sexan Co., Ltd. Concrete pile pile)
Shaft 2 diameter = 400φ,
Node 3 diameter = 550φ
Total length = 11.0m
Shaft 2 cross-sectional area = 0.0684m ²
Pile actual volume = 0.92m ³
Pile hole 5 Shaft 7 diameter = Shaft 2 diameter of ready-made pile 1 + 30 mm
= 580φ
Depth = 11.5m
Shaft 7 cross-sectional area = 0.264 m ²
Root consolidation part 6 length = 2m
Cement milk injection amount of root hardening part 6 (100% water cement ratio)
= 0.527m ³
Pile circumference (shaft part 7) Cement milk injection amount (100% water cement ratio)
= 0.790m ³ / 10m

[2] Relationship between injection volume, pile volume, etc. and corresponding pile hole length

Pile hole excavation length corresponding to the cement milk injection amount of the root hardening part 6 (hereinafter referred to as “equivalent excavation length”)
0.527 ÷ 0.264 ≒ 2.0m
Excavation length equivalent to the amount of cement milk (pile circumference fixing liquid) injected into the pile circumference 12
0.75 ÷ 0.264 ≒ 2.8m
The actual volume of the ready-made pile 1 and the equivalent excavation length
0.92 ÷ 0.264 ≒ 3.5m
In addition, the actual volume of the ready-made pile 1 is the volume of a ready-made pile, and refers to the volume of only parts, such as concrete except the volume of the hollow part.

[3] Configuration of excavation rod 10

  The excavation rod 10 is configured by attaching an excavation head 16 to the lower end of the rod body 11.

  The excavation head 16 has a connecting portion with the rod main body 11 at the upper end, a spiral 18 for earthing is formed on the outer periphery of the hollow cylindrical head main body 17, and fixed excavation blades 19, 19 at the lower end of the spiral 18. Is protruded with the cutting edge facing downward. Further, enlarged excavating blades 20 and 20 that expand in the radial direction (lateral direction) are attached to the middle portion of the spiral 18. A water injection port (not shown) is provided at the center of the lower end of the head body 17 so that water, cement milk, and the like can be appropriately injected into the pile hole 5 from the outside.

In the vertical direction (depth direction of Kuiana) the length and L _1, the length of the longitudinal direction of the cutting edge of the enlarged digging edge (depth direction of the Kuiana) L ₃ of the cutting edge of the fixed digging edge 19 It is as.

  The rod body 11 has a connecting portion with the excavation head 16 at the lower end, and a spiral 12 for earth removal is formed at the lower end. The spiral 12 is formed from the lower end of the digging blades 19 to a position of a length (height) L (L: at least 2 m or more) (FIG. 1). Above the spiral 12, a kneading drum and a stirring bar (not shown) are mounted, and no means for discharging soil (such as a spiral) is provided. The length L of the spiral 12 is set according to the amount of soil discharged as described above.

  The kneading drum 13 has a flat partial fan-shaped kneading portion 14 detachably attached to a drum mounting portion 13 a fixed to the head body 17. The kneading portions 14 are formed with an opening angle of about 90 degrees in plan view, and two kneading portions 14 are arranged at diametrically symmetrical positions. The upper and lower portions of the kneading portion are gradually reduced in diameter to form an introduction portion 15 in which the kneading surface 14a is narrowed obliquely.

Further, in the above, the longitudinal length of the mixing with portion 14 of the mixing with the drum 13 (the depth direction of the Kuiana) and L _2.

[4] Construction method of foundation pile 25

  The construction method is a normal pre-digging pile hole creation method, in which a measure is added to prevent the pile hole from collapsing according to the soil quality of the ground, and the excavation soil discharge method is changed from the conventional method. Specifically, foundation piles are constructed in the following procedure.

(1) The excavation rod 10 is rotated forward from the ground 22 and the ground is excavated by the fixed excavation blades 19 and 19 of the excavation head 16 (FIG. 1A). At this time, in the case where the soil has collapsibility (for example, sandy soil), excavation is performed while water is poured as needed.

(2) First, the pile hole 5 is excavated from the ground 22 to a depth of 4.8 m, and the excavated soil (corresponding to the amount of cement milk injected) is discharged to the ground 22 by spirals 18 and 12 (FIG. 1 (a)). Chain line shown 5). At this time, if necessary, the excavation rod 10 can be raised for efficient earth removal or the like. In addition, since the excavated soil discharged does not contain drilling fluid or cement milk other than water, it can be disposed of as general residual soil (non-industrial waste).

(3) Subsequently, or in parallel with excavation, a steel pipe casing 23 having an inner diameter (slightly larger than the excavation diameter) into which the excavation rod 16 can be inserted is installed in the pile hole opening 8 so that the pile hole wall near the ground Prevent collapse. Here, the excavation rod 16 is once lifted to the ground together with the earth removal, but if the excavation rod 16 has sufficient earth excavation capacity and the casing can be installed after the predetermined earth excavation, the excavation rod 16 is raised to the ground. There is no need.
The depth (length) H of the casing 23 in the above is about 4 of the length of the pile hole corresponding to the amount of cement milk injected into the root consolidation portion, that is, the “equivalent excavation length” of the amount of solidifying agent injected. .8 m (FIG. 2B).

(4) Subsequently, the ground is excavated to a predetermined depth (depth 11.5 m) with the excavation head 16 of the excavation rod 10. At this time, the excavation head 16 is excavated with appropriate water injection to assist excavation, and the excavation rod 10 is raised and lowered up and down, and the excavated soil and water are well agitated and excavated by the kneading drum 13. Knead the soil into the pile hole wall. By this stirring, the pile hole wall can be further prevented from collapsing, and the quality of the soil cement produced thereafter can be improved.
Unlike the conventional pile hole creation method, the pile hole 5 having a high-quality pile hole wall is different from the conventional pile hole creation method by adopting the following method so that the pile can be piled even after the excavated soil is discharged from the pile hole 5. Even if the hole wall collapses less and the soil quality (ground property) differs by depth in one pile hole 5, stable and reliable ready-made piles can be laid.

(5) Further, during the excavation, the length of the cutting edge in the depth direction of the fixed excavation blade 19 of the excavation head 16 is L ₁ (cm), the number of the cutting edges is n ₁ (pieces), and the rotation speed of the excavation rod 10 Is the excavation speed (pushing speed in the depth direction) v (cm / min.) Of the N (rpm) excavation head 16,
v ≦ L ₁ × n ₁ × N [Formula A]
The excavation speed v and the rotational speed N of the excavation rod 10 are adjusted so as to satisfy the above. By satisfy | filling Formula A, it can excavate so that a blade edge may scrape a pile hole wall at least once, it can excavate a pile hole wall without exception, and it will become a uniform pile diameter.
When the length in the depth direction of the kneading surface 14a by the kneading drum 13 of the excavating rod 10 is L ₂ (cm) and the number of kneading surfaces 14a having the same height is n ₂ (pieces),
v ≦ L ₂ × n ₂ × N [Formula B]
In order to satisfy the above, stirring and kneading are performed by adjusting the drilling speed v and the rotational speed N of the drilling rod 10. By satisfy | filling Formula B, the kneading surface 14a can level a pile hole wall at least once, and uniform kneading can be performed.
Here, in the case of excavation creation in a pile hole in normal ground, from Formula A, Formula B,
v / N = L ₁ × n ₁
v / N = L ₂ × n ₂
If the excavation rod 10 excavation speed v and the rotation speed N are adjusted so as to satisfy both formulas, the formation of the pile hole 5 can be realized most efficiently.
Also, if the ground is not good soil that tends to collapse, from Formula A and Formula B,
L ₁ × n ₁ = k ₁ , L ₂ × n ₂ = k ₂ ,
And when
v / N ≦ L ₁ × n ₁ = k ₁ [Formula C]
v / N ≦ L ₂ × n ₂ = k ₂ [Formula D]
If the value of “v / N” as small as possible is set so as to satisfy the condition, the number of times of kneading can be increased and the kneading can be performed thicker. That is,
v / N = (1/2) × k ₂
If v and N are set so that, the pile hole wall can be kneaded at least twice.

(6) When excavation, agitation, and kneading of the shaft portion 7 of the pile hole 5 is completed, the lower end of the excavation head 16 is positioned on the pile hole bottom 8a (FIG. 2 (b)), and a predetermined amount of preset is set. The cement milk for root consolidation part is discharged, the excavated soil left in the planned position of the root consolidation part 6 is pushed up, and it replaces with cement milk. Depending on the soil quality of the root consolidation part 6, cement milk can be discharged while stirring with excavated soil, and a root consolidation part with a desired solidification strength can be created.

(7) When the formation of the root consolidation part 6 is completed, the cement milk for the pile circumference fixing liquid is discharged from the tip of the excavation head 16 into the shaft part 7 of the pile hole 5 while pulling up the excavation rod 10. Further, the excavating rod 10 is moved up and down and / or rotated to agitate and mix the discharged cement milk and excavated soil to form a homogeneous soil cement layer, and the soil cement is kneaded to the pile hole wall. When the formation of the predetermined soil cement and the pile hole wall is completed, the casing 23 is pulled up to the ground 22 and the excavation rod 10 is also lifted to complete the formation of the pile hole 5 (FIG. 2 (c)).
In this state, a predetermined uniform soil cement layer (pile circumference fixing liquid layer) can be formed up to the vicinity of the pile hole mouth 8 of the pile hole 5 (a position corresponding to the pile head).

(8) Subsequently, the ready-made pile 1 is set in the pile hole 5. As the ready-made pile 1 is buried, the soil cement is filled between the hollow portion 1a of the ready-made pile 1 and the pile hole wall, and the soil cement overflows the ground 22.
When soil cement is filled up to the hole 8 of the pile, it is preferable because the soil cement adheres to the surface of the ready-made pile 1 without touching the excavated soil. 3.5m) of soil cement overflows the ground 22, and the overflowed soil cement is recovered and treated as industrial waste. Even in this case, the amount treated as industrial waste is reduced to about one-half or less as compared with the conventional method with the same pile hole diameter. The solidifying agent used can be saved as well.

(9) As described above, the filled soil cement and cement milk are solidified and integrated with the ready-made pile 1, and the construction of the foundation pile 25 of the present invention is completed (FIG. 2 (d)).

[5] Other embodiments

(1) In the above embodiment, first, the excavation length of about 5 m corresponding to the cement milk injection is raised to the ground 22 at the time of excavation on the surface side, and the pile hole discharge is treated as general residual soil. The pile hole discharge corresponding to the volume of excavation length of 3.5m was treated as industrial waste, and the pile hole mouth 8 was reinforced with a casing. However, the soil of the construction ground such as hard clay caused the collapse of the pile hole wall. If there is no danger, the casing 23 may not be used (not shown).
That is, during excavation of the pile hole, before the cement milk injection, 7.6 m of excavated soil is discharged from the ground in advance and treated as general residual soil. Up to this depth, the inside of the pile hole is emptied, 4.8m of the required cement milk is poured into the pile hole 5, and the excavated soil left in the pile hole and the cement milk are stirred and mixed. 5 to produce soil cement. Next, if the ready-made pile 1 is sunk, the 3.8 m portion corresponding to the actual volume of the ready-made pile 1 is empty, so that the soil cement is piled in the state where the ready-made pile 1 is buried to a predetermined depth. It reaches to the vicinity of the hole 8 (near the pile head), but it does not overflow to the ground. Accordingly, it is possible to substantially eliminate the discharge of excavated soil (soil cement) mixed with cement milk treated as industrial waste.

(2) In the above embodiment, the casing 23 was pushed into the upper part of the pile hole 5 for about 5 m to prevent the pile hole wall near the pile hole 8 from collapsing, but the construction ground is relatively less collapsible. Instead of pushing the casing 23, the pile hole 5 can be filled with water (not shown).
That is, after excavating 5 m of excavated soil from the ground 22 during excavation of the pile hole, water is injected into the pile hole 5 and the pile hole 5 is excavated in a state where water is always filled up to the vicinity of the pile hole opening 8. do. With the excavated soil and water in the pile hole 5, the pile hole 5 is excavated to a predetermined depth, and the excavated soil is stirred to level the pile hole wall.
Subsequently, if cement milk is injected into the root consolidation part 6 and the excavated soil of the root consolidation part 6 at the lower end of the pile hole is replaced or stirred with cement milk, the excavated soil or water above the pile hole 5 is Since no cement milk is mixed with the pile hole discharge overflowing and overflowing, it can be treated as general residual soil (non-industrial waste). Here, the depth of about 2.0 m of excavated soil (cement milk not mixed) in the upper part of the pile hole is discharged to the ground 22.
Subsequently, cement milk is injected and stirred into the shaft portion 7 of the pile hole 5 to form a pile peripheral fixed liquid layer by soil cement.
Subsequently, the ready-made pile 1 is buried in the pile hole 5.
In this case, since the pile circumference fixing liquid (excavated soil mixed with cement milk) equivalent to the volume of the ready-made pile 1 is discharged, this is treated as industrial waste, but the industrial waste to be treated is This can be reduced by about 25% compared to the conventional case.
Here, if a pile circumference fixed liquid layer by soil cement is not formed, a layer of excavated soil or water is formed above the root solidified liquid layer in the pile hole 5, and the specific gravity of water is the soil cement or cement. Since it is smaller than the specific gravity of milk (about 1.5 to 1.8), it is not mixed unless it is mixed. Therefore, if the ready-made pile 1 is buried, only excavated soil and / or water in which the cement milk above the root consolidation part 6 is not mixed is discharged to the ground. Therefore, the pile hole discharge can be treated as general residual soil (non-industrial waste).

(3) Also, in the foundation pile structure 25, the foundation base (such as a footing) is usually constructed by digging up the periphery of the foundation pile to a few meters below from the hole hole 8 and filling the concrete again. Therefore, in the said Example, although the soil cement was filled to the pile hole opening 8, the cement milk layer (pile circumference fixed liquid layer) around the pile hole opening 8 (pile head) was not formed beforehand, or was removed. (Not shown). In this case, an embodiment in which water is filled in the above-mentioned pile hole side without forming a cement milk layer is effective.

(4) Moreover, in the said Example, depending on the supporting force calculated | required by the foundation pile, the injection | pouring of the cement milk to the pile hole 5 is from the root solidified part 6 of the pile hole 5 lower part to the upper axial part (pile peripheral part) 7. Although the soil cement layer was formed in the order, the cement milk could be injected from the top to the bottom by reversing the injection order. When this method is adopted, a soil cement can be formed economically and easily.

  In this case, the excavated soil corresponding to the cement milk injection amount is discharged from the pile hole 5 in advance, and the pile hole 5 is excavated to the hole bottom 8a so that the excavated soil enters the pile hole 5. Subsequently, cement milk is poured into the upper part of the pile hole 5 and mixed with the excavated soil to form a soil cement layer (pile circumference fixing liquid layer). If necessary, the soil cement is kneaded into the pile hole wall. Apply and level. Subsequently, cement milk is injected at the root hardening portion 6 to replace the excavated soil, or by stirring and mixing with the excavated soil, a soil cement is formed.

(5) Further, in the above embodiment, the root hardening portion 6 has the same diameter as the shaft portion 7, but the bottom excavation can also be performed with the enlarged excavating blade 20 (shown in FIG. 2 with a chain line 6). In this case, since the amount of cement milk injection corresponding to the expanded bottom diameter increases, the excavated soil of the ground surface portion to be discharged increases accordingly.

(6) Moreover, in the said Example, the donut-shaped accommodating part 30 can also be formed in the periphery of the pile hole mouth 8 of the pile hole 5 at the time of a pile hole excavation (refer FIG.4 (d)). Housing section 30, for example, in diameter of about twice the drilling diameter D ₁ of the Kuiana 5 is formed at a depth 1m about. If the accommodating part 30 is formed, when the ready-made pile 1 is set in the pile hole 5, the soil cement overflowing from the pile hole 5 to the ground 22 can be accommodated, and the soil cement in the accommodating part 30 is contained in the pile hole 5. Solidifies integrally with the soil cement (see FIG. 4 (f)). Therefore, the soil cement as industrial waste overflowing from the pile hole 5 can be consumed in the field, and industrial waste to be disposed of can be further reduced.
In this case, the saving effect of the solidifying agent to be used is reduced, but the amount of soil discharged on the first surface 22 side can be reduced only by the volume of the container 5, and the amount of cement milk used can be increased. Furthermore, since the strength of the ground surface at the construction site can be reinforced to a practical strength, it is particularly effective when ground improvement on the ground 22 side is required.

(7) Further, in the above embodiment, the excavation length corresponding to the cement milk injection was raised to the ground 22 at the time of excavation on the surface side, and the pile hole discharge was treated as general residual soil. It is also possible to raise excavated soil corresponding to the integral of the pile to the ground 22 and treat the pile hole discharge as general residual soil.

  Next, another embodiment will be described.

[1] Construction specifications

Ready-made pile 1 Concrete pile for both lower pile, middle and upper pile Lower pile BFS pile (Trademark of Mitani Sekisan Co., Ltd.)
(Nickname: 700-6075)
Total length = 6.5m
Upper shaft length = 5m
Lower shaft length = 1.5m
Node diameter = 750φ,
Lower shaft diameter = 600φ
Upper shaft diameter = 700φ
Middle / Upper pile
PHC pile 30 m
(10m x 3 splices)
Pile outer diameter = 700φ
Pile wall thickness = 100mm
Pile cross-sectional area = 1.88m ² / 10m
Pile hole Shaft excavation diameter = 780φ
Shaft cross section = (78/2) x (78/2) x 3.14
≒ 0.477m ²
Cement milk injection amount (60% of water cement)
Root consolidation part = 2.38 m ³
Shaft part = 0.478m ³ / 10m

[2] Relationship between pile hole length corresponding to injection volume, pile volume, etc.

Cement milk injection amount equivalent excavation length Rooting part 2.38 ÷ 0.477 ≒ 5.0m
Pile circumference 0.478 ÷ 0.477 × 3 ≒ 3.0m
Pile actual volume and equivalent excavation length 6.64 ÷ 0.477 ≒ 14.0m

[3] Construction method of foundation pile

  The construction method is a normal pre-digging pile hole creation method, in which a measure is added to prevent the pile hole from collapsing according to the soil quality of the ground, and the excavation soil discharge method is changed from the conventional method. Specifically, as in Example 1, a foundation pile is constructed in the following procedure.

(1) The excavation head 16 a used in this embodiment has fixed excavation blades 19 and 9 at the lower end of the head main body 17 connected to the rod main body 11, and the base ends of the excavation arms 31 and 31 on both sides of the head main body 17. Are configured to be swingable (FIG. 1B). In this excavation head 16a, the excavation arms 31 and 31 are swung to one side by the forward rotation of the excavation rod 10, and the excavation blades 32 and 32 at the tip of the excavation arm 31 can excavate so as to cut the pile hole wall. The pile hole bottom is excavated by the fixed excavating blades 19 and 19 of the main body 17 (FIG. 1B). Further, the reverse rotation of the excavation rod 10 causes the excavation arms 31 and 31 to swing to the other side at a larger angle, and the excavation blades 32 and 32 at the distal end of the excavation arm 31 can be used to enlarge and excavate the rooted portion (not shown). Absent).

(2) The excavation head 16a is connected to the rod main body 11 of the first embodiment, and the excavation rod 10 is rotated forward from the ground 22 by the fixed excavation blades 19 and 19 and the excavation blades 32 and 32 of the excavation head 16a. If necessary, water is poured and the ground is excavated in the same manner as in Example 1 (see FIG. 1A). First, the pile hole 5 is excavated from the ground 22 to a depth of about 8 m, and the excavated soil (corresponding to the amount of cement milk injected) is discharged to the ground by the spirals 18 and 12 (FIG. 1 (a), the chain line shown in FIG. 5). The excavated soil discharged does not contain drilling fluid or cement milk other than water, so it can be disposed of as general residual soil (non-industrial waste).

(3) Subsequently or in parallel with excavation, a steel pipe casing (length of about 8 m) 23 having an inner diameter (slightly larger than the excavation diameter) into which the excavation rod 16 can be inserted is installed in the pile hole 8. , Prevent the pile hole wall near the ground 22 from collapsing. At this time, the shape of the pile hole can be reliably maintained by sequentially pushing the casing while excavating the excavating rod through the casing.

(4) Subsequently, the ground is excavated to a predetermined depth (depth 35 m) with the excavation head 16 of the excavation rod 10.
In the foundation pile structure 25 of this embodiment, if a high-quality pile hole 5 is created, the bearing capacity can be about twice as high as that of the conventional foundation pile structure 25 with the same diameter pile hole 5. That is, the formula C and the formula D of the first embodiment.
v / N ≦ L ₁ × n ₁ = k ₁ [Formula C]
v / N ≦ L ₂ × n ₂ = k ₂ [Formula D]
For example,
v / N ≦ (1/2) × k ₁
v / N ≦ (1/2) × k ₂
If the excavation rod 10 is operated by setting “decrease excavation speed v” and / or “increase the number of rotations”, the pile hole wall can be cut multiple times with the fixed excavation blade at the same depth. It can be piled up and piled up several times.

(5) While excavating and kneading under the above-mentioned conditions setting, to the predetermined depth (about 35 m), taking into account the collapse property of the ground, excavability, etc., as in Example 1 above. A high quality pile hole 5 is created. According to the excavation under such conditions, the quality of the soil cement can be improved when the pile hole wall is improved and the excavated soil is finely and more uniformly pulverized and then mixed with cement milk.

(6) When excavation is completed up to the bottom (bottom end) 8a of the pile hole, the excavation rod 10 is reversely rotated to open the enlarged excavation blades 20 and 20 to expand the pile hole wall (FIG. 2 (b)). Chain line shown 6). When the length L ₃ (m) in the depth direction of the enlarged digging blade 20 and the number of enlarged digging blades 20 at the same height are n ₃ (pieces), the equation D
v ≦ L ₃ × n ₃ × N [Formula D]
And transform this
v / N ≦ L ₃ × n ₃ = k ₃ [Formula E]
And here,
v / N ≦ (1/3) × k ₃
The excavation rod 10 is operated so that the excavation speed v is decreased and / or the rotation speed is set to be large so that the enlarged pile hole wall is formed more uniformly, and the excavation in the pile hole 5 is performed. While further finely pulverizing the soil, an enlarged diameter rooting portion (excavation diameter 1100 mm, height 2.5 m) 6 is formed (FIG. 2, chain line illustration 6).

(7) When the formation of the pile hole 5 is completed, cement milk is injected from the discharge port at the lower end of the excavation head 16 at the hole bottom 8a (deepest part) of the root hardening part 6. At this time, the excavation head 16 is rotated (moved up and down) a plurality of times in the root consolidation unit 6 while rotating, and is stirred and mixed with the excavated soil while injecting a predetermined amount of cement milk to obtain a root made of homogeneous soil cement. A firm layer is formed.
Here, cement milk can be injected from the bottom of the pile hole and replaced with excavated soil, and cement root can be filled into the root consolidation portion 6 to form a root consolidation layer.

(8) Subsequently, the excavation head 16 is raised, and the excavation head 16 is moved up and down while pouring a predetermined amount of cement milk from the discharge port at the shaft portion 7 of the pile hole 5, so that the cement milk and the excavation soil are removed. The soil cement is produced by stirring and mixing, and the soil cement is kneaded to the pile hole wall, and the pile hole wall is further uniformly and uniformly provided to have a predetermined size. When the creation of a predetermined high quality pile hole is completed, the excavation rod is pulled up (see FIG. 2C). In this state, the pile hole 5 is filled with uniform soil cement up to the pile hole port 8.

(9) Subsequently, the ready-made pile 1 is sunk in the pile hole 5, and the foundation pile structure is constructed after the soil cement is solidified (see FIG. 2 (d)). At this time, the soil cement of the integral integral of the ready-made pile 1 overflows from the ground surface 22 and is collected. This collected soil cement (substance integral of ready-made pile 1) is classified and treated as industrial waste. Since the discharge amount of the residual soil as the industrial waste is limited to the substantial integral of the ready-made pile 1, the amount treated as the industrial waste is greatly reduced (about 40%) as in the first embodiment.

(10) Other Embodiments As in the first embodiment, when the construction ground is strong and there is no risk of collapse of the pile hole wall, the casing 23 is not used, and the ground is previously ground before the cement milk is poured. 22, 21.9 m of excavated soil can be discharged as general residual soil (non-industrial waste) (not shown). In this case, there is almost no discharge of the excavated mud to the ground 22 when the cement milk is injected into the root consolidation portion and when the ready-made pile 1 is set up, and the residual soil mixed with cement milk as industrial waste can be eliminated.
Moreover, in the case of this Example, compared with the conventional foundation pile structure of the same pile hole diameter, in order to obtain about 2 times as high supporting force, high-quality construction management is required for creation of the conventional pile hole 5 Except for this, the other embodiments are the same as the first embodiment.
Moreover, in the said Example, the doughnut-shaped accommodating part 30 can also be formed in the periphery of the pile hole port 8 of the pile hole 5 at the time of a pile hole excavation similarly to Example 1 (refer FIG.4 (d)). Accommodating portion, for example in the size of about 4 times the drilling diameter D ₁ of the Kuiana 5 is formed at a depth 1m about. Similar to the first embodiment, when the accommodating portion 30 is formed, the soil cement overflowing from the pile hole 5 to the ground 22 can be accommodated when the ready-made pile 1 is set in the pile hole, and the soil cement in the accommodating portion 30 is stored. Solidifies integrally with the soil cement in the pile hole (see FIG. 4 (f)).

It is a front view of the excavation rod used for implementation of this invention. (A)-(d) is the schematic longitudinal cross-sectional view explaining the excavation method of this invention. (A)-(e) is a conceptual diagram showing the process of the embodiment of this invention. (A)-(e), (f) is a conceptual diagram showing the process of the other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ready-made pile 1a Hollow part of ready-made pile 2 Shaft part of ready-made pile 3 Node part 5 of ready-made pile 5 Pile hole 6 Shaking part of pile hole 7 Shaft part of pile hole 8 Pile hole port 8a Pile hole bottom 10 Excavation rod 11 Rod body DESCRIPTION OF SYMBOLS 12 Spiral 13 Kneading drum 16, 16a Excavation head 17 Head main body 18 Spiral 19 Fixed excavation blade 20 Expansion excavation blade 22 Ground 23 Casing 25 Foundation pile 27 Root consolidation layer 28 Pile circumference fixed liquid layer 30 Accommodating part 31 Excavation arm 32 Excavation blade (Drilling arm)

Claims (6)

Roots compaction portion of the excavated Kuiana, by introducing a solidifying agent to form roots hardened layer, to the root consolidated layer, by embedding the prefabricated pile linked alone or profiles pile hollow profiled Piles A method for constructing a foundation pile for constructing a pile , wherein a pile peripheral portion is formed above the root-solidified portion of the pile hole, and a pile peripheral fixed liquid layer is formed from the injected solidifying agent. A construction method of foundation pile characterized by taking.
(1) Divide the solidification agent injection amount W1 to be poured into the root consolidation part by the pile hole cross-sectional area in advance to set an equivalent excavation length A, and set the solidification agent injection amount W2 to be introduced into the pile peripheral part. The equivalent excavation length B is set by dividing by the pile hole cross-sectional area, the volume excluding the volume of the hollow portion of the ready-made pile is taken as the actual volume, and the actual volume is divided by the cross-sectional area of the pile hole to obtain the equivalent excavation length. Set C.
(2) An excavating blade having a length L corresponding to the amount of earth excavated is formed above the excavating blade, and a kneading drum is mounted on the excavating means without providing an excavating means, and excavating. Configure the rod.
(3) in the drill rod, the Kuiana upper portion from the ground surface, the corresponding drilling length A, and the corresponding equivalent drilling length B and the corresponding drilled length C drilling on the earth surface side of the excavated soil To discharge. The discharged excavated soil is treated as general residual soil.
(4) Subsequently, the pile hole is excavated to a predetermined depth, a solidifying agent is injected into the pile hole, and "replaced with the remaining excavated soil" and / or "stirred and mixed with the remaining excavated soil" are mixed. ”To form a root consolidation layer and to form a pile circumference fixing liquid layer above the root consolidation layer .
(5) Subsequently, the ready-made pile is sunk in the pile hole, and the upper surface of the pile fixing liquid layer is placed in the pile hole, and the excavated soil mixed with the solidifying agent is not discharged to the ground. Roots compaction portion of the excavated Kuiana, by introducing a solidifying agent to form roots hardened layer, to the root consolidated layer, by embedding the prefabricated pile linked alone or profiles pile hollow profiled Piles A method for constructing a foundation pile for constructing a pile , wherein a pile peripheral portion is formed above the root-solidified portion of the pile hole, and a pile peripheral fixed liquid layer is formed from the injected solidifying agent. A construction method of foundation pile characterized by taking.
(1) The amount of solidification agent injected into the root consolidation part is divided by the pile hole cross-sectional area in advance to set an equivalent excavation length A, and the amount of solidification agent injection W2 injected into the pile periphery fixing part. Is divided by the pile hole cross-sectional area to set the equivalent excavation length B, the volume excluding the volume of the hollow portion of the ready-made pile is taken as the actual volume, and the actual volume is divided by the pile hole cross-sectional area to obtain the equivalent excavation length Set C.
(2) An excavating blade having a length L corresponding to the amount of earth excavated is formed above the excavating blade, and a kneading drum is mounted on the excavating means without providing an excavating means, and excavating. Configure the rod.
(3) in the drill rod, the Kuiana upper portion from the ground surface, the corresponding drilling length A, and the corresponding equivalent drilling length B and the corresponding drilled length C drilling on the earth surface side of the excavated soil To discharge. The discharged excavated soil is treated as general residual soil.
(4) Subsequently, the pile hole is excavated to a predetermined depth, a solidifying agent is injected into the pile hole, and "replaced with the remaining excavated soil" and / or "stirred and mixed with the remaining excavated soil" are mixed. ”To form a root consolidation layer and to form a pile circumference fixing liquid layer above the root consolidation layer .   After discharging the "predetermined amount of excavated soil" to the ground or before discharging it, insert a casing with a length corresponding to the amount of discharged soil into the pile hole mouth, and excavate the pile hole The construction method of the foundation pile according to claim 1 or 2.   3. Construction of a foundation pile according to claim 1 or 2, wherein the pile hole is excavated in a state where water is filled up to the pile hole mouth before or after the "predetermined amount of excavated soil" is discharged to the ground. Method. Based on the required bearing capacity, in the foundation pile structure that designed the ready-made pile with the standard value of the pile hole of the predetermined diameter and depth, the predetermined outer diameter, inner diameter and length,
“The outer diameter of the ready-made pile is larger than the standard value” and / or “The inner diameter of the ready-made pile is smaller than the standard value”, the actual volume of the ready-made pile is set larger than the standard value,
The construction of a foundation pile according to claim 1 or 2, characterized in that a built-up pile having a relatively large actual volume compared to the volume of the pile hole is embedded in combination to relatively reduce the amount of solidifying agent used. Method.   Excavation of the ground around the pile hole mouth of the pile hole at a predetermined depth with a diameter of “1.5 times the diameter of the pile hole” to “a diameter that does not interfere with the adjacent pile hole” to form a housing part The construction method of the foundation pile of Claim 1 or 2 to do.

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