JP2007315027A - Construction method for foundation pile, structure of foundation pile, and designing method for foundation pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reasonable foundation pile structure utilizing a supporting force of an intermediate support layer acting on the front end of a foundation pile, and to simplify construction. <P>SOLUTION: In the ground having intermediate support layers 3 and a lower end support layer 2, a pile hole is drilled for each of dividing depth units H1 to H3 to set unit piles 12. Foundation pile structures 10A to 10C are set to calculate vertical loads P<SB>A</SB>, P<SB>B1</SB>, P<SB>B2</SB>, and P<SB>C</SB>that are transmitted through the foundation pile structures 10A to 10C, respectively. The structure of the foundation pile structure 10A is determined from load conditions including a horizontal load and a drawing load, and the vertical load P<SB>A</SB>born by the foundation pile structure 10A is determined. The structure of each of the foundation pile structures 10B<SB>1</SB>etc. is determined temporarily. This gives a total transmitted vertical load P=P<SB>A</SB>+P<SB>B1</SB>+P<SB>B2</SB>+P<SB>C</SB>, where a vertical load P<SB>B1</SB>=P-P<SB>A</SB>, a vertical load P<SB>B2</SB>=P-P<SB>A</SB>-P<SB>B1</SB>, a vertical load P<SB>C</SB>=P-P<SB>A</SB>-P<SB>B1</SB>-P<SB>B2</SB>. Whether each foundation pile structure can bear each vertical load is verified from a ground condition to adjust the structure of each foundation pile structure and a vertical load born by the same. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The purpose of this invention is to provide a rational support capacity in the foundation pile construction method, foundation pile construction method, foundation pile construction method for excavating pile holes and burying ready-made piles in the ground with an intermediate support layer And

  In the tip support pile, the foundation pile structure was comprised by burying the ready-made pile which connected the independent ready-made pile or several unit pile in the pile hole excavated to the support layer. In this case, in the support pile, the integral ready-made pile was embed | buried in a pile hole, and the root hardening liquid or the pile periphery fixing liquid was interposed between the pile hole and the ready-made pile.

In such a foundation pile, the vertical load, the pulling force, and the horizontal load that should be borne by one foundation pile are considered, and the tip support layer is designed to bear all the vertical loads. In addition, the friction force on the peripheral surface of the ready-made pile that is exhibited in the middle is ignored, so that even if the friction force is not zero, the tip of the ready-made pile bears the entire load of the pile head Had to design.
JP-A-4-93488 JP 2002-348868

  In the case of the conventional tip support pile, even if there is a slightly hard intermediate support layer in the middle of the tip support layer, the support force cannot be borne by the intermediate support layer.

  In addition, a structure that can effectively take the ground of the intermediate support layer as a support force has not been proposed.

  Moreover, in the conventional foundation pile, since it became large diameter more than needed in the intermediate part, and the weight also increased according to the large diameter, there was a problem that it was too heavy to be constructed. In order to avoid such a heavy machine weight limit, the length of the ready-made piles has to be shortened, and the connection work of the ready-made piles becomes complicated. In particular, it is a significant problem in the case of a large diameter exceeding 1 m in outer diameter.

  Moreover, in one pile hole, it was necessary to bury the ready-made pile continuously and rigidly connected by band or welding. For example, when only two or three stakes of 10m are connected for the convenience of the site, all have to be turned the next day. Therefore, the construction period was wasted.

  However, the present invention is a ground having an intermediate support layer, excavating a pile hole upper end forming a rooted portion in the uppermost intermediate support layer, and capable of bearing a pulling force and a horizontal load in the pile hole upper end. Therefore, the vertical load borne by the lower end pile can be reduced by effectively utilizing the support force of the intermediate support layer by the upper end pile, thus solving the above-mentioned problems.

That is, according to the present invention, in a ground having a “lower end support layer” and “one or more intermediate support layers”, a foundation pile is built by burying a ready-made pile in an excavated pile hole as follows. It is the construction method of the foundation pile characterized by this.
(1) The said pile hole is comprised from the pile hole upper end part of the uppermost intermediate support layer from the ground, and the lower end part of the pile hole from the lowermost intermediate support layer and the lower end support layer. When there are other intermediate support layers between the intermediate support layers, a pile hole intermediate portion is formed between each of the intermediate support layers.
(2) The support pile includes an upper end pile buried in the upper end portion of the pile hole, a lower end pile piled in the lower end portion of the pile hole, and a necessary intermediate pile. The intermediate pile is configured to be embedded in a corresponding pile hole intermediate portion when the pile hole intermediate portion exists.
(3) First, the pile hole is excavated from the ground to the bottom support layer.
(4) Next, the lower end pile corresponding to the length of the lower end portion of the pile hole is embedded in the lower end portion of the pile hole.
(5) Next, when each said pile hole intermediate part exists, each intermediate part pile is embed | buried in each pile hole intermediate part. The lowermost intermediate pile is placed on the upper end of the lower end pile, and the intermediate piles are stacked one above the other so as not to cause shaft misalignment.
(6) Next, at the upper end of the uppermost intermediate pile or lower pile, it has a length corresponding to the length of the upper end of the pile hole and resists the required pulling force and horizontal force. An upper end pile having

Moreover, in the above, when excavating a pile hole, it is the construction method of the foundation pile characterized by excavating as follows.
(1) Excavate the upper end of the pile hole, and store the excavation speed and accumulated current value data of the excavation in correspondence with the excavation depth direction or the ground N value of the depth.
(2) If there is an intermediate part of the pile hole, the excavation speed and the accumulated current value data of the excavation are made to correspond to the excavation depth direction or the ground N value of the depth for each excavation of the intermediate part of each pile hole. ,save.
(3) Excavate the lower end of the pile hole, and save the excavation speed and accumulated current value data of the excavation in correspondence with the excavation depth direction or the ground N value of the depth.

  Also, here, for each predetermined unit depth, the amount of water used during excavation is used so that the average integrated resistance value has a proportional relationship with the ground N value measured in advance, and the data of the amount of water used is a unit. It is a foundation pile construction method characterized by collecting and storing at each depth.

Moreover, in the above, after the root hardening liquid of a lower end part pile solidifies, it is the construction method of the foundation pile which embeds the intermediate part pile or upper end part pile located upward. Moreover, it is the construction method of the foundation pile which connected the upper end part of the foundation pile, comprised the footing which comprises the lower end surface of a ground structure, and comprised the lower surface by the same horizontal surface. Moreover, the lower end position of the lower end pile is located in the lower end support layer, the lower end position of the upper end pile is located in the intermediate support layer located at the top,
When an intermediate support pile exists, the lower end position of each intermediate support pile is located in each corresponding intermediate support layer, It is the construction method of the foundation pile characterized by the above-mentioned.

In another aspect of the present invention, in the ground having a lower end support layer and one or a plurality of intermediate support layers, a foundation pile formed by embedding a pre-made pile in the formed pile hole as follows. Structure.
(1) The said ready-made pile is comprised from a some unit pile, and the lower end part of each unit pile is located in the lower end support layer or intermediate support layer which adjoins up and down.
(2) The unit piles located above and below are not connected to each other, and the lower surface of the unit pile located above is placed on the upper surface of the unit pile located below.
(3) The unit pile located at the top has a structure that resists the pulling force and horizontal force required for the foundation pile.

  In the above, the unit pile has a foundation pile structure in which a protrusion is formed on the outer periphery of the lower end and the protrusion is positioned in the lower end support layer or the intermediate support layer.

In addition, in the ground having the lower end support layer and one or more intermediate support layers, the other invention constitutes a foundation pile structure by burying a ready-made pile in the formed pile hole as follows, It is a design method of foundation pile characterized by designing the necessary bearing capacity.
(1) The ready-made pile is composed of a plurality of unit piles, and the lower end portion of each unit pile is positioned in the lower end support layer or the intermediate support layer adjacent to each other in the vertical direction. The unit piles located on the top and bottom will not be rigidly connected, but will be installed with their axes aligned.
(2) First, determine the structure of the unit pile and the upper end of the pile hole, such as the pile diameter, so that the unit pile located at the top has the performance to withstand the pulling load and horizontal load required for the foundation pile. Units pile located in this top on the assumption that is supported on the intermediate support layer at the top, to calculate a vertical load unit pile and Kuiana upper end of the uppermost can bear, and vertical load P _A.
(3) Next, a unit pile located at the bottom end and fixed to the bottom support layer,
(Total vertical load P should be the burden of the foundation piles) - (vertical load _{P A} + vertical load _P B)
Assuming that the vertical load calculated by is transmitted, the structure of the unit pile located at the lowermost end and the structure of the lower end portion of the pile hole including the lower end support layer are determined.
(4) The vertical load B is set only when there are two or more intermediate support layers. In the case of ground having n intermediate support layers in addition to the uppermost intermediate support layer,
Vertical load P _B = Vertical load P _B1 + Vertical load P _B2 +... + Vertical load P _Bn
And However, the vertical loads P _B1 ,..., And the vertical loads P _Bn are the vertical loads defined by the following (5).
(5) In the case of (4), vertical load transmitted to each unit pile B ₁ , unit pile B ₂ ,..., Unit pile B _n is vertical load P _B1 , vertical load P _B2 ,. _Let P _Bn be
Vertical load P _B1 = (Total vertical load P to be borne by foundation pile) − (Vertical load P _A )
Vertical load P _B2 = (Total vertical load P to be borne by foundation pile)
- (vertical load _{P A} + vertical load _{P B1)}
Vertical load P _Bn = (Total vertical load P to be borne by foundation pile)
- (vertical load _P A + (vertical load _{P B1} + vertical load _P B2 + ··· + vertical load _{P Bn-1))}
As each vertical load _P B1, _..., based on the _{P Bn,} Unit pile _B 1 to bear it, to determine ..., the structure of _{B n.}

  Further, in the above, the pile heads of a plurality of foundation piles corresponding to the ground structure are connected by footing, the footing constituting the lower end surface of the ground structure, the bottom surface is constituted by a substantially horizontal plane, and the unit located at the top It is a setting method of the foundation pile which determines the structure of the unit pile located in the top so that it may have the performance which resists the drawing load, the horizontal load, and the vertical load which are required for the foundation pile with the pile and the footing .

  According to this invention, the structure of the ready-made pile can be an optimum structure for each depth of the ground, and it is not necessary to select a material having a larger diameter than necessary, and an appropriate structure is selected from the construction period, cost, etc. it can.

  Moreover, since it can also construct by using a ready-made pile having a large diameter and a relatively long length, it is possible to construct a foundation pile structure having a larger diameter and exhibiting a large supporting force by using the ready-made pile.

  Moreover, since a deeper pile hole and a unit pile can be made into a small diameter, the diameter of the pile hole excavated in a deep position can be made into a small diameter compared with the past. Therefore, a significant increase in bearing capacity can be expected based on the excavation diameter at the lower end.

  In addition, since it is not necessary to rigidly join the unit piles, complicated connection work is unnecessary and the construction period can be shortened.

1. Design of foundation pile structure 10

  Example of using grounding structure 6 (building) footing 7 as an independent foundation for piled rafts in the ground where there is one intermediate supporting layer 3 at an intermediate depth to the lower end supporting layer 2 (supporting ground) Will be described. Therefore, the ready-made pile is composed of two parts, a lower end pile 13 whose lower end is fixed to the lower support layer 2 and an upper end pile 12 whose lower end is fixed to the intermediate support layer 3. Therefore, the pile hole 20 consists of the pile hole lower end part 23 corresponding to the lower end part pile 13, and the pile hole upper end part 21 corresponding to the upper end part pile 12 (FIG. 1, FIG. 2).

(1) This invention uses the footing 7 as an independent foundation, applies a piled raft structure, and supports the vertical load of the ground structure 6 with the footing 7 and the six foundation pile structures 10 and 10.

If the total vertical load on the ground structure 6 was _{P total,} the vertical load of the footing 7 are borne _{P F,} the foundation pile structures 10 and 10 the vertical load to be borne is P,
_{P total} = P F + P
The vertical load P to be borne by one foundation pile structure 10 is
_{P = (P total -P F)} ÷ 6
It becomes.

The ground is
-Lower end support layer 2 (support ground layer) with N value (30) at a depth of about "H ₁ + H ₃ " from the ground 1
· N value _{H 1} a depth of about the ground first intermediate support layer (15) 3
Is present.

(2) The structure (outer diameter, etc.) of the upper end pile 12 is determined assuming that the horizontal load and the pulling force to be borne are all borne by the upper end piles 12 and 12 (FIG. 1B) c).
-Upper end pile 12: Length L ₁ , outer diameter D ₁
An annular protrusion 15 having an outer diameter D ₀₁ is formed at the lower end.
The cylindrical cover 19 is fixed to the outer periphery of the lower end. • Pile hole upper end portion 21: length H ₁ , outer diameter D ₁₁
Form roots 22 in the intermediate support layer 3

(3) With this upper end pile 12, the root consolidation part 22 is positioned in the intermediate support layer 3, the pile hole upper end part 21 is excavated, and the annular protrusion 15 is located within the root consolidation part 22 of the pile hole 20. considering the foundation pile structure 10A, the vertical load of the foundation pile structure 10A can bear the P _a.

(4) Then, the vertical load _{P C} to be imposed on the foundation pile structure of the lower end pile 13 (10) C. Since the vertical load to be borne by the entire foundation pile structure 10 is the total vertical load P,
(Vertical load to be borne by foundation pile C) P _C =
(Vertical load borne by the foundation pile structure A) (total vertical load) P- _{P A}
Accordingly, determining the vertical load _{P C.}

(5) determining the structure of the lower end pile 13 which can bear the vertical load _{P C} (Fig. 2 (a) (b)).
- the lower end pile 13: length L2, an outer diameter _{D 3 (D 3 <D 1} )
Forming an annular projection 16 of the outer diameter D ₀₃ to the lower end
The upper part 19a of the cylindrical cover 19 is fixed to the outer periphery of the lower end. ・ Pile hole lower end part 23: length H ₃ , outer diameter D ₃₃
A root 24 of the pile hole lower end portion 23 is formed in the lower end support layer 2.

(6) The foundation pile structure 10 is determined as described above.

(7) In the above, when the piled raft structure is not adopted, in (1), when the total vertical load of the ground structure 6 is P _total , the vertical load that one foundation pile structure 10 should bear P is
P = (P _total ) ÷ 6
It becomes.

(8) In the above, the case where there are two or more intermediate support layers that can be effectively used for securing the support force will be described with reference to FIG. For example, if there are a total of three intermediate support layers,
Above ground to the second intermediate support layer: H ₁
1st intermediate support layer to 2nd intermediate support layer: H ₂₁
2nd intermediate support layer to 3rd intermediate support layer (intermediate support layer located at the bottom): H ₂₂
Third intermediate support layer (intermediate support layer located at the bottom) to lower end support layer: H ₃
And Pile holes and unit piles are set for each of the depth units H1, H ₂₁ , H ₂₂ and H ₃ to be divided, and the foundation pile structure to be constructed is 10A, 10B ₁ , 10B ₂ and 10C. vertical load _P a transmitting _obtains the _{P B1, P B2, P C} .

Similarly to the above, first, the structure of the foundation pile structure 10A is determined from the load condition of the horizontal load and the pull-out load, and the ground condition (N value, etc.). Further, vertical load _{P A} that can be borne by the foundation pile structure 10A is determined.

From the determined structure of the foundation pile structure 10A, the structure of the foundation pile structures 10B ₁ , 10B ₂ , 10C is provisionally determined so as to have a smaller diameter, and the vertical load transmitted to each foundation pile structure is
_{P = P A + P B1 +} P B2 + P C
So
・ Vertical load P _B1 = P−P _A
・ Vertical load P _B2 = P−P _A −P _B1
・ Vertical load P _C = P−P _A −P _B1 −P _B2
It becomes. Thereby, it is verified from the ground conditions (N value or the like) whether or not the vertical load to be borne can be borne by each foundation pile structure, and the structure of each foundation pile structure and the vertical load to be borne are adjusted. The above is summarized in Table 1.

The vertical load is, for example,
・ Vertical load P = 10t
· Vertical load _P A = 4t
・ Vertical load P _B1 = 3t
・ Vertical load P _B2 = 2t
· Vertical load _P C = 1t
Confirm as follows. Because it reduces the vertical load P _C to transmit the foundation pile structure 10C, (diameter of = Kuiana lower end 23, the diameter of the unit piles 13) diameter of the foundation pile structure 10C to be reduced.

2. Construction of foundation pile structure 10

(1) Excavation of pile hole 20;
-Pile hole upper end 21: Above ground 1 to depth H ₁ : Diameter D ₁₁
· Kuiana lower portion 23: the depth _{H 1} ~ depth _{H 3:} diameter _{D 33 (D 33 <D 11} )
Then, the pile hole 20 is excavated. The root hardening part 24 of the pile hole lower end part 23 is filled with a root hardening liquid, and the other depth of the pile hole lower end part 23 is filled with a pile circumference fixing liquid.

(2) A cylindrical cover 19 is attached to the outer periphery of the lower end portion of the upper end pile 12, and the lower portion 19 b of the cover 19 is protruded downward from the lower surface 12 b of the upper end pile 12. The lower part 19 b of the cover 19 can be fitted to the upper end part of the lower end part pile 13.

(3) The lower end pile 13 is inserted into the pile hole 20 and the upper end of the lower end pile 13 is temporarily held near the ground 1.

  Subsequently, the lower surface 12 b of the upper end pile 12 is placed on the upper surface 13 a of the lower end pile 13. In this state, since the lower portion 19b of the cover 19 is fitted to the outer periphery of the upper end portion of the lower end pile 13, the upper end pile 13 and the lower end pile 12 are vertically overlapped so that the axes are not displaced, and a vertical load is applied. In such a case, the eccentric load does not act (FIG. 1 (d)).

(4) Subsequently, the holding of the lower end pile 13 near the ground is released, and the lower end pile 13 and the upper end pile 12 are inserted into the pile hole 20 in a stacked state.

(5) the annular projection 16 of the lower end pile 13, located in the root consolidated portion 24 of Kuiana lower portion 23, the length _{D 3} of about the lower surface 23a of the lower surface 13b is Kuiana lower end 23 of the lower end pile 13 The lower end pile 13 and the upper end pile 12 are held on the ground 1 while being positioned above.

Under the present circumstances, the upper surface 13a of the lower end part pile 13 is located in the root hardening part 22 (intermediate support layer 3) of the pile hole upper end part 21, and the lower surface 12b of the upper end part pile 12 is lower than the lower surface 21a of the pile hole upper end part 21. located in length D ₁ about the upper, annular projection 15 is located in the root consolidated portion 22 of Kuiana upper portion 21.

  In this state, a root hardening liquid is injected into the lower end portion of the pile hole upper end portion 21 to form the root hardening portion 22, and the lower end portion including the annular protrusion 15 of the upper end portion pile 12 is positioned in the root hardening portion 22. .

In the pile hole upper end portion 21, the pile periphery fixing liquid is filled above the root consolidation portion 22.

(6) Subsequently, the pile head of the foundation pile structure 10 (upper end pile 12) is exposed, and if necessary, the ground 1 is dug down to construct the footing 7, and the foundation pile structure 10 (upper end pile 12). ) Pile heads. The footing 7 is configured to satisfy the functions of the piled raft independent foundation.

  That is, the rigidity is increased by increasing the number of structural reinforcing bars, etc., and the entire lower surface 8 is configured to have substantially the same height (that is, the lower surface 8 is formed to be substantially flat) so as not to cause uneven settlement.

  As described above, the foundation pile structure 10 of the present invention is constructed (FIGS. 1A and 1B).

(7) Subsequently, a ground structure (building) 6 is constructed on the footing 7 by a normal method (FIGS. 1A and 1B).

The foundation pile structure of this invention is demonstrated based on drawing.

[1] Ground conditions

(1) The ground conditions are
First intermediate support layer at a depth of 10m from the ground N value (20)
Second intermediate support layer at a depth of 20m N value (30)
Lower end support layer at a depth of 30m N value (50)
The vertical load that should be borne by one foundation pile structure is 1000t. The pulling load is 5 t and the horizontal load is 10 t.

  The foundation pile structure 10 is configured by burying a ready-made pile 11 in a pile hole 20.

(2) In this case, it is assumed that a conventional structure in which a pre-made pile is embedded is adopted. The outer diameter of the ready-made pile buried in the pile hole needs to be 120 cm. When the ready-made pile has an outer diameter of 120 cm and a length of 10 m, the weight of one pile becomes about 771.6 t, and the construction becomes impossible. Considering the maximum handling weight of heavy machinery (usually about 500 to 600t), the maximum diameter (outside diameter) of ready-made piles will be about 100cm, and the number of ready-made piles will have to be increased, which is expected to make construction complicated. Is done.

[2] Foundation pile structure 10

(1) Therefore, by applying the present invention, the pile hole 20 is divided by the intermediate support layer, and the first intermediate support layer, the second intermediate support layer or the lower end support is provided for each divided pile hole 21, 25, 23. The unit piles 12, 14, and 13 are embedded in the divided pile holes 21, 25, and 23, respectively, with the layer as a rooted portion (Table 2).

  The structure of each unit pile 12, 14, 15 is as follows. The upper end pile 12 is formed with an annular protrusion (node) 15 over the entire length, the intermediate pile 14 is formed with an annular protrusion (node) 17 over the entire length, and the lower end pile 13 is formed with an annular protrusion (node) 17 over the entire length. ing. Moreover, it is set as the structure which formed the axial diameter of the lower end part thinly, and was made to correspond with the axial diameter of the unit pile connected below. The reduced diameter is processed below the annular protrusions (nodes) 15 and 17 of each unit pile (FIG. 4, Table 3).

  Moreover, the pile hole 20 corresponding to each unit pile is comprised like Table 3 as node diameter + 3cm.

  A cylindrical cover 19 is attached to the outer periphery of the lower end of the intermediate pile 12. The inner diameter of the cover 19 is the lower end shaft diameter of the intermediate pile 12 (= the shaft diameter of the lower end pile). Similarly, a cylindrical cover 19 having a corresponding inner diameter is attached to the outer periphery of the lower end of the upper end pile 12.

With this structure,
・ Foundation pile structure 10A = upper end pile 12 pile hole upper end 21 (root consolidation part: first intermediate support layer)
・ Foundation pile structure 10B = intermediate pile 14 intermediate pile portion 25 (root consolidation portion: second intermediate support layer)
-Foundation pile structure 10C = lower end pile 13 pile hole upper end 23 (root consolidation part: lower end support layer)
Configure.

[3] Design of foundation pile structure 10

The configuration of [2] is determined as follows.
(1) The foundation pile structures 10A, 10B, and 10C divided by the first intermediate support layer and the second intermediate support layer are set.
(2) The structure of the foundation pile structure 10A (the structure of the upper end pile 12 and the pile hole upper end part 21, the pile hole filler) is provisionally set based on the horizontal load / pulling load to be supported by the foundation pile structure 10A.
(3) foundation pile structure 10A, and calculates the vertical load _{P A} can be supported by the N value of the first intermediate support layer (20).
(4) Vertical bearing force P that the foundation pile structure 10 should bear,
P = P _A + P _B1 + P _B2 + P _C = 1000 t
More, assuming a vertical bearing force _{P B1, P B2, P C} to be transmitted to each foundation pile structure _{10B 1,} 10B 2, 10C, to determine the structure of each foundation pile structure 10B1,10B2,10C.
(5) It is verified whether or not the vertical support force P can be borne by the structures of the determined foundation pile structures 10B1, 10B2, and 10C and adjusted.
(6) The structure of each foundation pile structure 10B1, 10B2, 10C is determined as mentioned above (Table 3).
(7) In addition, in the above case (Table 3), with P = 1000t, each foundation pile structure 10A, the vertical load _P A that is transmitted to _{10B1,10B2,10C, P B1, P B2,} P C the following It is like that.
・ P _A = 1000t
・ P _B1 = 600t
・ P _B2 = 300t
・ P _C = 150t

[4] Construction method

Next, the construction method will be described.

(1) lower support layer to (depth _{H 1 + H 2 + H 3} = 30m), drilling head in the usual manner, drilling pile hole with diameter _{D 33.} Subsequently, the second intermediate support layer until (depth _{H 1 + H 2 = 20m)} , is expanded by conventional methods diameter from _{D 11} to _{D 22.} Subsequently, the diameter is expanded from D ₂₂ to D ₁₁ by a usual method up to the first intermediate support layer (depth H ₁ = 10 m). The pile hole 20 is constructed as described above.

(2) Subsequently, the lower end pile 13, the intermediate portion pile 14, and the upper end pile 12 are embedded in the pile hole in this order, the lower end pile 13 is the lower end support layer, the intermediate portion pile 14 is the second intermediate support layer, and the upper end. The piles are fixed to the first intermediate support layer.

  A root hardening liquid corresponding to the ground is injected into the lower end of the pile hole lower end 23, the lower end of the pile hole intermediate part 25, and the lower end of the pile hole upper end 21. Filled with liquid. Pile circumference fixing liquid is injected into a depth position corresponding to the shaft portion of the pile hole lower end portion 23. The lower end pile 13 is embedded in the lower end portion 23 of the pile hole by a normal method.

Injection timing of the roots hardened liquid and pile circumferential fixative is arbitrary as long as pile holes drilled later shaft D _33, it can be injected at a pulling time or separately injection tube at the lower end drilling head.

  In addition, the piles 13, 14, and 12 are placed through the cap 19 so that their axes are not displaced and are not rigidly joined. Therefore, the piles can be rotated and moved up and down until the pile periphery fixing liquid is solidified. It has become.

(3) The foundation pile structure 10 is constructed as described above.

(4) In this foundation pile structure 10, since it is a structure which supports the vertical load transmitted for every divided foundation pile structure 10B1, 10B2, 10C, it is necessary to embed each pile 13, 14, 12 continuously. There is no. For example, after fixing the lower end pile 23 to the lower end portion 13 of the pile hole (after the root hardening liquid has solidified, for example, several days later), the pile hole intermediate portion pile 14 is embedded in the pile hole intermediate portion 25. You can also.

Therefore, if the pile hole is also excavated after the D ₃₃ pile hole is excavated, the lower end pile 13 can be buried first even before the diameter of the pile hole D ₂₂ is expanded. However, in this case, it is necessary to support the lower end pile 13 on the ground until the root hardening liquid is solidified.

Therefore, throughout the construction site, the foundation pile construction required position, to build Kuiana lower end 23 first drilling diameter D _33, each pile hole bottom portion 23 by embedding the lower end pile 13 in order Subsequently, the foundation pile structure 20 can be completed by burying the intermediate pile 14 and the upper pile 12 while expanding each pile hole to D ₂₂ and D ₁₁ . Further, at each build position, we will build a Kuiana 20 completed drilling Kuiana was expanded to diameter D _11, in the next to Kakukuiana 20 sequentially lower end pile 13, the intermediate section piles 14, the upper end The foundation pile structure 20 can also be completed by burying the part pile 12.

  In addition, in the state where the pile periphery fixing liquid in the lower pile hole is solidified or solidified, a rooting liquid having a higher specific gravity than the lower pile periphery fixing liquid can be injected into the intermediate support layer directly above. Conventionally, it has been difficult to form a heavy-weight root-solidifying solution on top of a light-specific gravity pile-fixing solution, but according to this method, an intermediate support layer can be used without using a special jig. , A solidified layer can be formed in the corresponding pile hole.

  Furthermore, since it is not necessary to construct the lower end pile 13, the intermediate portion pile 14, and the upper end pile 12 in succession by combining these, the lower end pile 13, the intermediate portion pile 14, the upper end portion on different days. Since it is also possible to construct the pile 12, the foundation pile structure can be completed according to the loading status of the heavy machinery and the piles 13, 14, and 12. Therefore, the construction period can be saved and efficient construction can be performed.

[5] Other embodiments

(1) In the said Example, although each unit pile 13, 14, 12 reduced the diameter of the axial part, it was made to correspond to the axial diameter of the unit pile located below, If it can be embedded, it can be a structure that does not reduce the diameter (FIG. 2).

  Moreover, in the said Example, although each unit pile 13,14,12 formed the cyclic | annular protrusion (node) over the full length, an annular protrusion (node) was formed at least in the lower end part, and the annular protrusion (node) was rooted. If it can arrange | position in a firm part, it is good (FIG. 1, FIG. 2). Further, the annular protrusion (node) can be omitted if a sufficient tip support force can be secured without the annular protrusion (node) (FIG. 3).

(2) Moreover, in the said Example, although the foundation pile structure 10 (the ready-made pile 11) was divided | segmented with the intermediate | middle support layer, if a supporting force can be exhibited with a lower end support layer and each intermediate support layer, ie, intermediate support. If an annular protrusion (node) corresponding to the layer can be positioned, it is possible to connect a pre-made pile other than the intermediate support layer. Also in this case, it is not necessary to make a rigid joint.

(3) Moreover, in the said Example, if there is at least 1 intermediate | middle support layer, it can implement. In this case, the foundation pile structure 10 is comprised only from the foundation pile structure 10A (the upper end pile 12, the pile hole upper end part 22) and the foundation pile structure 10C (the lower end pile 14, the pile hole lower end part 24) (illustrated). Not)

(A) is a figure showing the plane structure of the foundation pile structure of this invention, (b) is the longitudinal cross-sectional view similarly generalized. (A) is a figure showing the structure of the ready-made pile used for the foundation pile structure of FIG. 1, (b) is a figure of the ready-made pile connected similarly. It is a conceptual diagram in case there are three intermediate | middle support layers of this invention. It is a front view of the ready-made pile used in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground 2 Lower end support layer 3 Intermediate support layer 6 Ground structure 7 Footing 8 Bottom surface of footing 10 Foundation pile structure (whole)
10A, 10B, 10B1, 10B2, 10C Foundation pile structure (part)
11 Ready-made pile 12 Upper end pile (unit pile)
13 Lower end pile (unit pile)
14, 14a, 14b Middle part pile (unit pile)
15 Annular projection (top pile)
16 Annular projection (Pile at the lower end)
17 Annular projection (intermediate pile)
19 Cover 20 Pile hole 21 Pile hole upper end part 22 Pile hole upper end part consolidation part 23 Pile hole lower end part 24 Pile hole lower end part consolidation part 25, 25a, 25b Pile hole middle part

Claims (10)

In the ground having a “lower end support layer” and “one or more intermediate support layers”, a foundation pile is constructed by burying a ready-made pile in an excavated pile hole as follows: How to build a pile.
(1) The said pile hole is comprised from the pile hole upper end part of the uppermost intermediate support layer from the ground, and the lower end part of the pile hole from the lowermost intermediate support layer and the lower end support layer. When there are other intermediate support layers between the intermediate support layers, a pile hole intermediate portion is formed between each of the intermediate support layers.
(2) The support pile includes an upper end pile buried in the upper end portion of the pile hole, a lower end pile piled in the lower end portion of the pile hole, and a necessary intermediate pile. The intermediate pile is configured to be embedded in a corresponding pile hole intermediate portion when the pile hole intermediate portion exists.
(3) First, the pile hole is excavated from the ground to the bottom support layer.
(4) Next, the lower end pile corresponding to the length of the lower end portion of the pile hole is embedded in the lower end portion of the pile hole.
(5) Next, when each said pile hole intermediate part exists, each intermediate part pile is embed | buried in each pile hole intermediate part. The lowermost intermediate pile is placed on the upper end of the lower end pile, and the intermediate piles are stacked one above the other so as not to cause shaft misalignment.
(6) Next, at the upper end of the uppermost intermediate pile or lower pile, it has a length corresponding to the length of the upper end of the pile hole and resists the required pulling force and horizontal force. An upper end pile having The method for constructing a foundation pile according to claim 1, wherein when excavating a pile hole, excavation is performed as follows.
(1) Excavate the upper end of the pile hole, and store the excavation speed and accumulated current value data of the excavation in correspondence with the excavation depth direction or the ground N value of the depth.
(2) If there is an intermediate part of the pile hole, the excavation speed and the accumulated current value data of the excavation are made to correspond to the excavation depth direction or the ground N value of the depth for each excavation of the intermediate part of each pile hole. ,save.
(3) Excavate the lower end of the pile hole, and save the excavation speed and accumulated current value data of the excavation in correspondence with the excavation depth direction or the ground N value of the depth.   Use the amount of water used at the time of excavation and collect data on the amount of water used at each unit depth so that the average integrated resistance value is proportional to the ground N value measured in advance for each predetermined unit depth. The foundation pile construction method according to claim 2, wherein the foundation pile is stored. The construction method of the foundation pile of Claim 1 or 2 which embeds the intermediate | middle part pile or upper end part pile located upward after the root hardening liquid of a lower end part pile solidifies.   The construction method of the foundation pile of Claim 1 or 2 which connected the upper end part of the foundation pile, and comprised the footing which comprises the lower end surface of an above-ground structure by the same horizontal surface. The lower end position of the lower end pile is located in the lower end support layer,
The lower end position of the upper end pile is located in the uppermost intermediate support layer,
The construction method of the foundation pile according to claim 1 or 2, wherein when an intermediate support pile exists, the lower end position of each intermediate support pile is located in each corresponding intermediate support layer. In a ground having a lower end support layer and one or a plurality of intermediate support layers, a foundation pile structure characterized in that a pre-made pile is embedded in a formed pile hole as follows.
(1) The said ready-made pile is comprised from a some unit pile, and the lower end part of each unit pile is located in the lower end support layer or intermediate support layer which adjoins up and down.
(2) The unit piles located above and below are not connected to each other, and the lower surface of the unit pile located above is placed on the upper surface of the unit pile located below.
(3) The unit pile located at the top has a structure that resists the pulling force and horizontal force required for the foundation pile. The structure of the foundation pile of Claim 7 which forms a processus | protrusion in a lower end part outer periphery, and this process part positions this processus | protrusion in a lower end support layer or an intermediate | middle support layer. In the ground having a lower end support layer and one or more intermediate support layers, the foundation pile structure is constructed by embedding pre-made piles in the formed pile holes as follows, and the necessary support force is designed. A design method for foundation piles.
(1) The ready-made pile is composed of a plurality of unit piles, and the lower end portion of each unit pile is positioned in the lower end support layer or the intermediate support layer adjacent to each other in the vertical direction. The unit piles located on the top and bottom will not be rigidly connected, but will be installed with their axes aligned.
(2) First, determine the structure of the unit pile and the upper end of the pile hole, such as the pile diameter, so that the unit pile located at the top has the performance to withstand the pulling load and horizontal load required for the foundation pile. Units pile located in this top on the assumption that is supported on the intermediate support layer at the top, to calculate a vertical load unit pile and Kuiana upper end of the uppermost can bear, and vertical load P _A.
(3) Next, a unit pile located at the bottom end and fixed to the bottom support layer,
(Total vertical load P should be the burden of the foundation piles) - (vertical load _{P A} + vertical load _P B)
Assuming that the vertical load calculated by is transmitted, the structure of the unit pile located at the lowermost end and the structure of the lower end portion of the pile hole including the lower end support layer are determined.
(4) The vertical load B is set only when there are two or more intermediate support layers. In the case of ground having n intermediate support layers in addition to the uppermost intermediate support layer,
Vertical load P _B = Vertical load P _B1 + Vertical load P _B2 +... + Vertical load P _Bn
And However, the vertical loads P _B1 ,..., And the vertical loads P _Bn are the vertical loads defined by the following (5).
(5) In the case of (4), the vertical load transmitted to each unit pile B ₁ , unit pile B ₂ ,..., Unit pile B _n is vertical load P _B1 , vertical load P _B2 ,. _Let P _Bn be
Vertical load P _B1 = (Total vertical load P to be borne by foundation pile) − (Vertical load P _A )
Vertical load P _B2 = (Total vertical load P to be borne by foundation pile)
- (vertical load _{P A} + vertical load _{P B1)}
Vertical load P _Bn = (Total vertical load P to be borne by foundation pile)
- (vertical load _P A + (vertical load _{P B1} + vertical load _P B2 + ··· + vertical load _{P Bn-1))}
As each vertical load _P B1, _..., based on the _{P Bn,} Unit pile _B 1 to bear it, to determine ..., the structure of _{B n.} The pile heads of a plurality of foundation piles corresponding to the ground structure are connected by footing, the footing that constitutes the lower end surface of the ground structure, and the lower surface is constituted by a substantially horizontal plane,
The structure of the unit pile located at the top is determined so that the unit pile located at the top and the footing have a performance against pulling load, horizontal load and vertical load required for the foundation pile. 9. Setting method of foundation pile according to 9.

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