JP2005299174A - Construction method of improved column body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method of improved column bodies that can considerably suppress the settlement of an unimproved part between the respective improved column bodies in the ground even if reducing the number of improved column bodies. <P>SOLUTION: In the construction method of the improved column bodies 15, the lower ends 15b of the improved column bodies 15 are constructed into a predetermined position to reach a bearing layer 11 below the soft ground 10, and pile head upper faces 15a of the improved column bodies 15 are formed to be almost flush with the upper face 10a of the soft ground 10. Further, a banking material 12 is mounded on the upper face 10a of the soft ground 10 and the pile head upper faces 15a of the improved column bodies 15. When a shearing angle in the banking material 12 to the peripheral edge of the pile head upper face 15a of the improved column body 15 is set to θ and an internal friction angle in the banking material 12 is set to ϕ, an expression θ=90°-ϕ is to be satisfied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for creating an improved column such as a soil cement column in soft ground, for example.

As an example of soft ground improvement by this type of improved column body building method, there is one shown in FIG. 7 (see, for example, Patent Document 1). In this soft ground improvement, as shown in FIG. 7, each lower end portion 5 a of the plurality of piles 5 is formed in the soft ground 1 to a position reaching the support layer 2 below the soft ground 1. Further, sand is laid on the upper surface of the soft ground 1 and the upper surface 5b of each pile head of the plurality of piles 5 to form a sand mat 3, and embankment such as high-quality earth and sand with little fear of subsidence on the sand mat 3. Filled with material 4
Japanese Patent Laid-Open No. 10-292360 JP 2003-64657 A

  However, in the conventional soft ground improvement, the unsettled amount of the unimproved portion between the piles 5 and 5 of the soft ground 1 is large, and the embankment material 4 is liable to sink or break in the unimproved portion. In order to cope with this, the number of piles 5 must be increased, and accordingly, the construction period took longer and the cost was increased.

  Therefore, the present invention has been made to solve the above-described problems, and even if the number of improved pillars is reduced, the amount of unsettled subsidence between the improved pillars of the ground can be greatly suppressed. An object of the present invention is to provide an inexpensive method for producing an improved column.

  In the invention of claim 1, the lower end portion of the improved column body is formed in the ground to a position reaching the support layer of the ground, and the upper surface of the ground and the upper surface of the pile head of the improved column body are substantially flush with each other. In the method of constructing an improved column body formed by embedding a filling material on the upper surface of the ground and the upper surface of the pile head of the improved column body, the edge of the upper surface of the pile head of the improved column body is When the shear angle in the embankment material is θ and the internal friction angle of the embankment material is φ, it is set to satisfy the equation θ = 90 ° −φ.

  The invention of claim 2 is a method for producing an improved pillar according to claim 1, characterized in that the shear angle θ in the embankment material is in the range of about 60 °.

  According to the invention of claim 3, the lower end of the improved column body is formed in the ground up to a position reaching the support layer of the ground, and the upper surface of the ground and the upper surface of the pile head of the improved column body are substantially flush with each other. And laying sand on the upper surface of the ground and the upper surface of the pile head of the improved column body and solidifying the surface layer, and then the upper surface of the ground and the pile head of the improved column body In the construction method of the improved pillar body formed by embanking the embankment material on the upper surface, θ ′ is the shear angle in the sand with respect to the periphery of the upper surface of the pile head of the improved pillar body, and θ is the shear angle in the embankment material, When the internal friction angle of the embankment material is φ, it is set to satisfy the formula θ ′ <θ = 90 ° −φ.

  A fourth aspect of the invention is a method for producing an improved pillar according to the third aspect of the invention, wherein a shear angle θ in the embankment material is set to a range of 60 ° or less.

  According to the invention of claim 5, the lower end portion of the improved column body is formed in the ground to a position that does not reach the support layer of the ground, and the upper surface of the ground and the upper surface of the pile head of the improved column body are substantially flush with each other. In the method of constructing an improved column body formed by embedding a filling material on the upper surface of the ground and the upper surface of the pile head of the improved column body, the peripheral edge of the upper surface of the pile head of the improved column body When the internal shear angle of the embankment material is θ and the internal friction angle of the embankment material is φ, it is set so as to satisfy the formula θ> 90 ° −φ.

  A sixth aspect of the invention is a method for producing an improved pillar according to the fifth aspect of the invention, wherein a shear angle θ in the embankment material is set to a range of 60 ° or more.

  In the invention of claim 7, the lower end portion of the improved column body is formed in the ground to a position not reaching the support layer of the ground, and the upper surface of the ground and the upper surface of the pile head of the improved column body are substantially flush with each other. And laying sand on the upper surface of the ground and the upper surface of the pile head of the improved column body and solidifying the surface layer, and then the upper surface of the ground and the pile head of the improved column body In the method of constructing the improved column body by embanking the embankment material on the upper surface of the pile, the shear angle in the solidified layer with respect to the periphery of the upper surface of the pile head of the improved column body is θ ′ and the shear angle in the embankment material is θ When the internal friction angle of the embankment material is φ, it is set so as to satisfy the equation θ ′ <θ> 90 ° −φ.

  The invention according to claim 8 is the method for producing the improved pillar according to claim 7, wherein the shear angle θ in the embankment material is set to a range of 60 ° or more.

  As described above, according to the invention of claim 1, the pile head of the improved column body in the bottoming type improved column body forming method in which the lower end portion of the improved column body is formed to the position reaching the support layer of the ground. By setting so that the shear angle in the embankment material with respect to the peripheral edge of the upper surface of θ is θ, and the internal friction angle of the embankment material is φ, θ = 90 ° −φ is set so as to satisfy the formula: While the amount of settlement of the unimproved portion in the meantime can be suppressed, the number of improved pillars can be reduced. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  According to the second aspect of the present invention, in the method of constructing the improved pillar body of the bottoming system, the unreformed portion between the respective improved pillar bodies of the ground is obtained by setting the shear angle θ in the embankment material to a range of about 60 °. The amount of subsidence can be suppressed, and the number of improved pillars can be reduced. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  According to the invention of claim 3, in the method of constructing the improved pillar body of the bottoming system, the shear angle in the sand is θ ′ and the shear angle in the embankment material is θ relative to the periphery of the upper surface of the pile head of the improved pillar body. When the internal friction angle of the embankment material is φ, by setting so as to satisfy the formula θ ′ <θ = 90 ° −φ, the amount of subsidence of the unimproved portion between the improved pillars of the ground is further increased. While being able to suppress further, the number of improved pillars can be further reduced. Thereby, the ground improvement of the ground can be performed in a short period of time and at low cost.

  According to the fourth aspect of the present invention, in the method of constructing the improved pillar body of the bottoming system, the unreformed portion between the improved pillar bodies of the ground is obtained by setting the shear angle θ in the embankment material to a range of 60 ° or less. The amount of subsidence can be further suppressed, and the number of improved pillars can be further reduced. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  According to invention of Claim 5, in the construction method of the floating type improved column body which forms the lower end part of the improved column body to the position which does not reach the support layer of the ground, the embankment with respect to the peripheral edge of the upper surface of the pile head of the improved column body When the internal shear angle is θ and the internal friction angle of the embankment material is φ, by setting to satisfy the formula of θ> 90 ° −φ, subsidence of the unimproved portion between each improved pillar of the ground The amount can be reduced and the number of improved columns can be reduced. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  According to invention of Claim 6, in the construction method of the floating type improved column body, the shear angle θ in the embankment material is set to a range of 60 ° or more, so that the unimproved portion between the improved column bodies of the ground is formed. The amount of settlement can be suppressed and the number of improved pillars can be reduced. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  According to the invention of claim 7, in the construction method of the floating type improved column body, the shear angle in the solidified layer with respect to the periphery of the upper surface of the pile head of the improved column body is θ ′ and the shear angle in the embankment material is θ, When the internal friction angle of the embankment material is φ, by setting so as to satisfy the formula θ ′ <θ> 90 ° −φ, the subsidence amount of the unimproved portion between the improved pillars of the ground is further increased. While being able to suppress, the number of improvement pillar bodies can be reduced further. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  According to invention of Claim 8, in the construction method of the floating-type improved pillar body, by setting the shear angle θ in the embankment material to a range of 60 ° or more, the unimproved portion between the improved pillar bodies of the ground The amount of settlement can be further suppressed, and the number of improved pillars can be further reduced. Thereby, the ground improvement of the ground can be performed in a short time and at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of the ground formed by the improved column forming method of the first embodiment of the present invention.

  As shown in FIG. 1, a lower end portion 15 b of a soil cement column (improved column) 15 is formed in a soft ground (ground) 10 to a predetermined position reaching the support layer 11 below the soft ground 10. Further, the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed to be substantially flush with each other, and the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed. An embankment material 12 such as high-quality earth and sand, which is less likely to sink, is embanked.

  Next, a procedure for improving the ground of the soft ground 10 by the method of forming the bottom soil cement column 15 will be described.

  First, the soil cement column 15 is formed in the soft ground 10 to a predetermined position where the lower end portion 15b reaches the support layer 11. At the time of this construction, construction is performed so that the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are substantially flush with each other.

Next, the embankment material 12 such as high-quality earth and sand having a low possibility of sinking is embanked on the upper surface 10 a of the soft ground 10 and the upper surface 15 a of the pile head of the soil cement column 15. At this time, when the shear angle in the embedding material 12 with respect to the periphery of the upper surface 15a of the pile head of the soil cement column 15 is θ, and the internal friction angle of the embedding material 12 is φ,
(Equation 1)
θ = 90 ° -φ
It is set so as to satisfy the above equation (1).

At this time, the subsidence amount Sc (m) of the unimproved portion between the soil cement columns (improved column bodies) 15 and 15 of the soft ground 10 is obtained by the following equation (2).
(Equation 2)
Sc = S ₀ · (ΔPc / ΔP)
Here, S ₀ is the untreated settlement amount (m), ΔPc is the embankment load (kN / m ² ) acting on the unimproved portion, and ΔP is the entire embankment load (kN / m ² ).

ΔP and ΔPc are obtained from the following equations (3), (4), and (5).
(Equation 3)
ΔP = V · γ / (λ + d) ²
Where V: total embankment volume (m ³ ) {= (λ + d) ² × H}, γ: embankment density (kN / m ³ ), λ: distance between improved columns (m), d: improved column The diameter of the body (m), H: the height of the embankment (m).

Here, Vc: fill volume (m ³ ) for applying a load to the unimproved portion.

Furthermore, Vc is obtained from the following equation (5).

Further, the settlement amount Sp of the soil cement column (improved column) 15 is obtained by the following equation (6).
(Equation 6)
Sp = (ΔPp / E) · L
Here, ΔPp: embankment load (kN / m ² ) acting on the improved column body, E: deformation coefficient (kN / m ² ) of the improved column body, and L: length (m) of the improved column body.

Further, the embankment load ΔPp acting on the improved column body is obtained from the following equations (7), (8), and (9).
(Equation 7)
E = 100 ・ qu
(Equation 8)
ΔPp = Vp · γ / (d / 4) ² π
(Equation 9)
Vp = V-Vc
Here, qu: uniaxial compressive strength (kN / m ² ) of the improved column body, Vp: embankment volume (m ³ ) that applies a load to the improved column body. At this time, ΔPp <qu is always satisfied.

Furthermore, the amount of unsettled subsidence ΔS (m) between the soil cement column (improved column body) 15 and the soil cement columns 15, 15 improved by the deep mixing treatment is the amount of settlement of the pile head of the soil cement column 15. From the settlement amount Sc of the unimproved portion between Sp and each of the soil cement columns 15, 15, the following formula 10 is used.
(Equation 10)
ΔS = Sc−Sp
In this way, in the construction method of the improved pillar body of the bottoming system in which the lower end portion 15b of the soil cement column 15 is constructed to a predetermined position reaching the support layer 11 below the soft ground 10, the pile head of the soil cement column 15 is By setting so that the shear angle in the embedding material 12 with respect to the periphery of the upper surface 15a is θ, and the internal friction angle of the embedding material 12 is φ, the equation of θ = 90 ° −φ in Equation 1 is satisfied. The subsidence amount Sc of the unimproved portion between the soil cement columns 15 and 15 of the soft ground 10 can be suppressed, and the number of the soil cement columns 15 can be reduced. Thereby, the ground improvement of the soft ground 10 can be performed in a short period of time and at low cost. In particular, when the shear angle θ in the embankment material 12 is set to 60 °, the ground improvement of the soft ground 10 can be performed more effectively.

  FIG. 2 is a cross-sectional view of the ground formed by the improved column forming method of the second embodiment of the present invention.

  As shown in FIG. 2, a lower end portion 15 b of a soil cement column (improved column) 15 is formed in a soft ground (ground) 10 to a predetermined position reaching the support layer 11 below the soft ground 10. Further, the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed to be substantially flush with each other, and the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed. The sand mat 13 is formed by laying the spread sand on the surface, and the surface layer is covered with a sheet 14 to strengthen the surface layer, and then the embankment material 12 such as high-quality earth and sand that is less likely to sink is embanked.

  Next, a procedure for improving the ground of the soft ground 10 by the method of forming the bottom soil cement column 15 will be described.

  First, the sand mat 13 is formed by laying laying sand on the upper surface 10 a of the soft ground 10. Next, the soil cement column 15 is formed in the soft ground 10 to a predetermined position where the lower end portion 15 b reaches the support layer 11. At the time of this construction, construction is performed so that the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are substantially flush with each other.

Next, after the surface of the sand mat 13 laid on the upper surface 10a of the soft ground 10 is covered with a sheet 14 and the surface layer is reinforced, the embankment material 12 such as high-quality earth and sand having a low possibility of sinking is placed on the sheet 14. Fill up. At this time, the shear angle in the sand mat (laying sand) 13 with respect to the peripheral edge of the upper surface 15a of the pile head of the soil cement column 15 is θ ′, the shear angle in the embankment material 12 is θ, and the internal friction angle of the embankment material 12 is φ. If
(Equation 11)
θ ′ <θ = 90 ° −φ
It sets so that the above formula 11 may be satisfied.

  Thus, when the shear angle in the spread sand 13 with respect to the periphery of the upper surface 15a of the pile head of the soil cement column 15 is θ ′, the shear angle in the embankment material 12 is θ, and the internal friction angle of the embankment material 12 is φ Further, by setting so as to satisfy the equation of θ ′ <θ = 90 ° −φ of the above formula 11, the soil cement columns 15 and 15 of the soft ground 10 between the soil cement columns 15 and 15 are not set as in the first embodiment. The amount of settlement Sc of the improved portion can be further suppressed, and the number of soil cement columns 15 can be further reduced. Thereby, the ground improvement of the soft ground 10 can be performed in a short period of time and at low cost. In particular, when the shear angle θ in the embankment material 12 is set in a range of 55 ° to 60 °, the ground improvement of the soft ground 10 can be more effectively performed.

  FIG. 3 is a cross-sectional view of the ground formed by the improved column forming method of the third embodiment of the present invention.

  In the second embodiment, the surface layer of the sand mat (laying sand) 13 is reinforced by covering it with the sheet 14. However, in the improved pillar body forming method of the third embodiment, the surface layer of the sand mat (laying sand) 13 ( The whole layer may be included. The original ground may also be included.) The only difference is that 13a is solidified with a solidifying material (not shown) such as cement or quicklime. The same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also in the third embodiment, the shear angle in the spread sand 13 with respect to the periphery of the upper surface 15a of the pile head of the soil cement column 15 is θ ′, the shear angle in the embankment material 12 is θ, and the internal friction angle of the embankment material 12 is φ. In this case, the soil cement columns 15 and 15 of the soft ground 10 are set in the same manner as in the first embodiment by setting so as to satisfy the equation of θ ′ <θ = 90 ° −φ of the above formula 11. The amount of settlement Sc of the unimproved portion in the meantime can be further suppressed, and the number of the soil cement columns 15 can be further reduced. Thereby, the ground improvement of the soft ground 10 can be performed in a short period of time and at low cost. In particular, when the shear angle θ in the embankment material 12 is set in a range of 55 ° to 60 °, the ground improvement of the soft ground 10 can be more effectively performed.

  FIG. 4 is a cross-sectional view of the ground formed by the improved column forming method of the fourth embodiment of the present invention.

  As shown in FIG. 4, the lower end portion 15 b of the soil cement column (improved column body) 15 is formed in the soft ground (ground) 10 to a predetermined position that does not reach the support layer 11 below the soft ground 10. . Further, the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed to be substantially flush with each other, and the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed. An embankment material 12 such as high-quality earth and sand, which is less likely to sink, is embanked.

  Next, a procedure for improving the ground of the soft ground 10 by the method for forming the floating soil cement column 15 will be described.

  First, the soil cement column 15 is formed in the soft ground 10 to a predetermined position where the lower end portion 15 b does not reach the support layer 11. At the time of this construction, construction is performed so that the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are substantially flush with each other.

Next, the embankment material 12 such as high-quality earth and sand having a low possibility of sinking is embanked on the upper surface 10 a of the soft ground 10 and the upper surface 15 a of the pile head of the soil cement column 15. At this time, when the shear angle in the embedding material 12 with respect to the periphery of the upper surface 15a of the pile head of the soil cement column 15 is θ, and the internal friction angle of the embedding material 12 is φ,
(Equation 12)
θ> 90 ° -φ
It sets so that the above formula 12 may be satisfied.

  In this way, in the method of constructing the floating type improved column body in which the lower end portion 15b of the soil cement column 15 is constructed to a predetermined position that does not reach the support layer 11 below the soft ground 10, the pile head of the soil cement column 15 is By setting so that the shear angle in the embedding material 12 with respect to the periphery of the upper surface 15a is θ and the internal friction angle of the embedding material 12 is φ, the equation of θ> 90 ° −φ in the above formula 12 is satisfied. The subsidence amount Sc of the unimproved portion between the soil cement columns 15 and 15 of the soft ground 10 can be suppressed, and the number of the soil cement columns 15 can be reduced. Thereby, the ground improvement of the soft ground 10 can be performed in a short period of time and at low cost. In particular, when the shear angle θ in the embankment material 12 is set to 82 ° to 84 °, the ground improvement of the soft ground 10 can be more effectively performed.

  FIG. 5 is a cross-sectional view of the ground formed by the improved column forming method of the fifth embodiment of the present invention.

  As shown in FIG. 5, the lower end portion 15 b of the soil cement column (improved column body) 15 is formed in the soft ground (ground) 10 to a predetermined predetermined position that does not reach the support layer 11 below the soft ground 10. It is. Further, the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed to be substantially flush with each other, and the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are formed. The sand mat 13 is formed by laying the spread sand on the surface, and the surface layer is covered with a sheet 14 to strengthen the surface layer, and then the embankment material 12 such as high-quality earth and sand that is less likely to sink is embanked.

  Next, a procedure for improving the ground of the soft ground 10 by the method for forming the floating soil cement column 15 will be described.

  First, the sand mat 13 is formed by laying laying sand on the upper surface 10 a of the soft ground 10. Next, the soil cement column 15 is formed in the soft ground 10 to a predetermined position where the lower end portion 15 b does not reach the support layer 11. At the time of this construction, construction is performed so that the upper surface 10a of the soft ground 10 and the upper surface 15a of the pile head of the soil cement column 15 are substantially flush with each other.

Next, after the surface of the sand mat 13 laid on the upper surface 10a of the soft ground 10 is covered with a sheet 14 and the surface layer is reinforced, the embankment material 12 such as high-quality earth and sand having a low possibility of sinking is placed on the sheet 14. Fill up. At this time, the shear angle in the sand mat (laying sand) 13 with respect to the peripheral edge of the upper surface 15a of the pile head of the soil cement column 15 is θ ′, the shear angle in the embankment material 12 is θ, and the internal friction angle of the embankment material 12 is φ. If
(Equation 13)
θ ′ <θ> 90 ° −φ
It is set so as to satisfy the above equation (13).

  Thus, when the shear angle in the spread sand 13 with respect to the periphery of the upper surface 15a of the pile head of the soil cement column 15 is θ ′, the shear angle in the embankment material 12 is θ, and the internal friction angle of the embankment material 12 is φ Further, by setting so as to satisfy the equation of θ ′ <θ> 90 ° −φ of the above equation 13, as in the fourth embodiment, the soil cement columns 15 and 15 of the soft ground 10 are not yet connected. The amount of settlement Sc of the improved portion can be further suppressed, and the number of soil cement columns 15 can be further reduced. Thereby, the ground improvement of the soft ground 10 can be performed in a short period of time and at low cost. In particular, when the shear angle θ in the embankment material 12 is set in the range of 75 ° to 82 °, the ground improvement of the soft ground 10 can be more effectively performed.

  FIG. 6 is a cross-sectional view of the ground formed by the improved column forming method of the sixth embodiment of the present invention.

  In the fifth embodiment, the surface layer of the sand mat (laying sand) 13 is reinforced by covering with the sheet 14, but in the improved column forming method of the sixth embodiment, the surface layer of the sand mat (laying sand) 13 ( The whole layer may be included. The original ground may also be included.) The only difference is that 13a is solidified with a solidifying material (not shown) such as cement or quicklime. The same components as those in the fifth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also in the sixth embodiment, the shear angle in the spread sand 13 with respect to the periphery of the upper surface 15a of the pile head of the soil cement column 15 is θ ′, the shear angle in the embankment material 12 is θ, and the internal friction angle of the embankment material 12 is φ. In this case, the soil cement columns 15 and 15 of the soft ground 10 are set in the same manner as in the fourth embodiment by setting so as to satisfy the equation of θ ′ <θ> 90 ° −φ of the above formula 13. The amount of settlement Sc of the unimproved portion in the meantime can be further suppressed, and the number of the soil cement columns 15 can be further reduced. Thereby, the ground improvement of the soft ground 10 can be performed in a short period of time and at low cost. In particular, when the shear angle θ in the embankment material 12 is set in the range of 75 ° to 82 °, the ground improvement of the soft ground 10 can be more effectively performed.

  In addition, according to each said embodiment, although the improved column body was comprised with the soil cement column, of course, the said each embodiment can be applied to improved column bodies other than a soil cement column.

It is sectional drawing of the ground created by the construction method of the improved pillar body of 1st Embodiment of this invention. It is sectional drawing of the ground created by the construction method of the improved pillar body of 2nd Embodiment of this invention. It is sectional drawing of the ground created by the construction method of the improved pillar body of 3rd Embodiment of this invention. It is sectional drawing of the ground created by the construction method of the improved pillar body of 4th Embodiment of this invention. It is sectional drawing of the ground created by the construction method of the improved pillar body of 5th Embodiment of this invention. It is sectional drawing of the ground created by the construction method of the improved pillar body of 6th Embodiment of this invention. It is sectional drawing which shows the improvement structure of the conventional soft ground.

Explanation of symbols

10 Soft ground (ground)
10a upper surface 11 support layer 12 embankment material 13 sand mat (laying sand)
14 Sheet 15 Soil cement column (improved column)
15a Upper surface of pile head 15b Lower end

Claims (8)

Forming the lower end of the improved column in the ground to a position reaching the support layer of the ground, and forming the upper surface of the ground and the upper surface of the pile head of the improved column so as to be substantially flush with each other; and In the construction method of the improved column body, which is embedding a fill material on the upper surface of the ground and the upper surface of the pile head of the improved column body,
When the shear angle in the embankment material with respect to the peripheral edge of the upper surface of the pile head of the improved column body is θ, and the internal friction angle of the embankment material is φ,
θ = 90 ° -φ
A method for constructing an improved column, characterized in that it is set so as to satisfy the following formula. A method for producing an improved column according to claim 1,
A method for producing an improved column, wherein a shear angle θ in the embankment material is set to a range of about 60 °. Forming the lower end of the improved column in the ground to a position reaching the support layer of the ground, and forming the upper surface of the ground and the upper surface of the pile head of the improved column so as to be substantially flush with each other; and Laying sand on the top surface of the ground and the top of the pile head of the improved column body and solidifying the surface layer, and then embedding a filling material on the top surface of the ground and the top surface of the pile head of the improved column body In the construction method of the improved pillar body,
When the shear angle in the sand is relative to the periphery of the upper surface of the pile head of the improved pillar body is θ ′, the shear angle in the embankment material is θ, and the internal friction angle of the embankment material is φ,
θ ′ <θ = 90 ° −φ
A method for constructing an improved column, characterized in that it is set so as to satisfy the following formula. A method for producing an improved column according to claim 3,
A method for producing an improved column, wherein a shear angle θ in the embankment material is set to a range of 60 ° or less. Forming the lower end of the improved pillar in the ground to a position that does not reach the support layer of the ground, and forming the upper surface of the ground and the upper surface of the pile head of the improved pillar to be substantially flush with each other, And in the creation method of the improved column body, which is embedding a fill material on the upper surface of the ground and the upper surface of the pile head of the improved column body,
When the fill material shear angle with respect to the peripheral edge of the upper surface of the pile head of the improved column body is θ, the internal friction angle of the fill material is φ,
θ> 90 ° -φ
A method for constructing an improved column, characterized in that it is set so as to satisfy the following formula. A method for producing an improved pillar according to claim 5,
A method for producing an improved column, wherein a shear angle θ in the embankment material is set to a range of 60 ° or more. Forming the lower end of the improved pillar in the ground to a position that does not reach the support layer of the ground, and forming the upper surface of the ground and the upper surface of the pile head of the improved pillar to be substantially flush with each other, And after laying laying sand on the upper surface of the ground and the upper surface of the pile head of the improved column body and solidifying the surface layer, embankment material is embanked on the upper surface of the ground and the upper surface of the pile head of the improved column body In the method of constructing the improved column,
When the shear angle in the solidified layer with respect to the peripheral edge of the upper surface of the pile head of the improved pillar is θ ′, the shear angle in the embankment material is θ, and the internal friction angle of the embankment material is φ,
θ ′ <θ> 90 ° −φ
A method for constructing an improved column, characterized in that it is set so as to satisfy the following formula. A method for producing an improved pillar according to claim 7,
A method for producing an improved column, wherein a shear angle θ in the embankment material is set to a range of 60 ° or more.

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