JP7007544B2 - Knot piles and joint piles - Google Patents

Description

This disclosure relates to knot piles and joint piles.

Ready-made piles applied to pile foundations are roughly classified into support piles and friction piles. The tip (bottom surface) of the support pile is reached to the support layer, and the support pile supports the superstructure by an upward force acting on the tip. In a friction pile, the superstructure is supported by the frictional force acting on the peripheral surface of the friction pile.
Conventionally, knot piles have been used as friction piles. The knot pile has a main body portion (shaft portion) and a plurality of annular knot portions projecting radially outward from the main body portion (see, for example, Patent Document 1). As a method of using the knot pile, there is a method of connecting a plurality of knot piles and using them as a joint pile.

Japanese Unexamined Patent Publication No. 2012-241500

The frictional bearing capacity of the pile peripheral surface generated between the soil cement (consolidation part or the peripheral part of the pile) surrounding the knot pile and the peripheral surface of the pile hole acts on the knot pile via the soil cement, and the knot part of the knot pile. Shear force is generated in. The friction bearing capacity of the pile peripheral surface changes depending on the peripheral friction coefficient of the foundation pile in the sandy ground, but the shear strength of the node is the maximum value of the friction bearing capacity of the pile peripheral surface generated in a short period (short-term maximum pile peripheral surface). It is desirable that it is larger than the friction bearing capacity).
On the other hand, in the knot pile, it is conceivable to increase the outer diameter of the main body in order to improve the horizontal strength. However, in this case, if the outer diameter of the main body is increased so as to surround the base of the conventional knot without changing the shape of the knot, the contact area between the main body and the knot (knot root area) becomes small. Become. As a result, the shear strength of the node is reduced. When the shear strength of the node is reduced in this way, the shear strength of the node becomes smaller than the short-term maximum pile peripheral friction bearing capacity.

In view of the above circumstances, an object of at least one embodiment of the present invention is that even when a short-term maximum pile peripheral friction bearing force acts on a knot pile, the shear strength of the knot is higher than the shear force acting on the knot. To provide large shear and joint piles.

(1) The knot pile according to at least one embodiment of the present invention is
Cylindrical body and
It is provided with at least two knots protruding from the outer peripheral surface of the main body.
The main body and the knots contain concrete and contain concrete.
Let Lr be the length of the base of the node on the main body side in the axial direction of the main body.
The length of the head of the node on the side opposite to the main body in the axial direction of the main body is Lt.
age,
The outer diameter of the main body is Dp.
When the protruding height of the node from the main body in the radial direction of the main body is Lh ,
The following formula:
Lr-2 × (3 ^ 0.5) × Lh ≦ Lt ≦ Lr-2 / (3 ^ 0.5) × Lh
Satisfy the relationship shown in
The outer diameter Dp of the main body is 600 mm or more and 1400 mm or less.
The length Lr at the base of the node is 230 mm or more and 300 mm or less.
The length Lt of the head of the node is 130 mm or more and 200 mm or less.
The protruding height Lh of the node is 40 mm or more and 100 mm or less.
The shear strength of the knot is determined by the root area of the knot and the short-term shear allowable stress of the concrete, and is larger than the short-term maximum pile peripheral friction bearing capacity per pitch of the at least two knots. ..

According to the above configuration (1), the length Lr at the base of the knot and the protruding height L h of the knot satisfy a predetermined relationship, and the knot is per at least two knots at a pitch. It has a shear strength larger than the short-term maximum pile peripheral friction bearing capacity . Therefore, the contact area between the main body and the node (the area at the base of the node) is sufficiently secured, and the shear strength of the node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the knot pile, the shear force of the knot portion is larger than the shear force acting on the knot part.
Further, according to the above configuration (1), the length Lt of the head of the node, the length Lr of the base of the node, and the protruding height Lh of the node satisfy a predetermined relationship, and the node The length Lt of the head of the head is sufficiently secured. Therefore, the short-term pile peripheral friction bearing capacity can be set based on the outer diameter of the node, and the short-term pile peripheral friction bearing capacity of a desired size can be realized.

(2) In some embodiments, in the above configuration (1),
When the short-term shear stress tolerance of the concrete is τ,
The length Lr at the base of the node is 230 mm or more and 300 mm or less.
The length Lt of the head of the node is 130 mm or more and 200 mm or less.
The protruding height Lh of the node is 50 mm, and the protrusion height Lh is 50 mm.
The pitch of the at least two nodes is 1 m.
The node is
The following formula:
Lr> 380 × (Dp + 2 × Lh) / (τ × Dp)
Satisfy the relationship indicated by.
According to the above configuration (2), the length Lr at the base of the node is 230 mm or more and 300 mm or less, and the protruding height Lh of the node is 50 mm, so that the contact area between the main body and the node is sufficient. It is secured and the shear strength of the node is sufficiently secured.
Further, according to the above configuration (2), the length Lt of the head of the node is 130 mm or more and 200 mm or less, and the length Lt of the head of the node is sufficiently secured.

(3) In some embodiments, in the above configuration (2),
The length Lr at the base of the node is 300 mm, and the length is 300 mm.
The length Lt of the head of the node is 200 mm .
According to the above configuration (3), since the length Lr at the base of the node is 300 mm and the protruding height Lh of the node is 50 mm, a sufficient contact area between the main body and the node is secured. Sufficient shear strength of the node is secured.
Further, according to the above configuration (3), the length Lt of the head of the node is 200 mm, and the length Lt of the head of the node is sufficiently secured.

(4) The joint pile according to at least one embodiment of the present invention is
In a joint pile provided with a first section pile and a second section pile connected to the first section pile.
The first section pile is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body portion and the first section portion include the first concrete, and the first main body portion and the first section portion include the first concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear allowable stress of the first concrete is τ1,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the allowable short-term shear stress of the first concrete, and the short-term maximum pile circumference per pitch of at least two first nodes. Greater than surface friction bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ1 × Dp1)
Satisfy the relationship shown in
The second section pile is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body portion and the second section portion include the second concrete, and the second main body portion and the second section portion include the second concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
Let Lh2 be the height of protrusion of the second node from the second main body in the radial direction of the second main body.
When the short-term shear allowable stress of the second concrete is τ2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second section is determined by the root area of the second section and the allowable short-term shear stress of the second concrete, and the short-term maximum pile circumference per pitch of at least two second sections. Greater than surface friction bearing capacity ,
The length Lr2 at the base of the second node is 300 mm.
The length Lt2 of the head of the second node is 100 mm, and the length Lt2 is 100 mm.
The protruding height Lh2 of the second node is 100 mm, and the protrusion height Lh2 is 100 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ2 × Dp2)
Satisfy the relationship shown in
The outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion.

According to the above configuration (4), in the first section pile, the length Lr1 at the base of the first section, the outer diameter Dp1 of the first main body, the protruding height Lh1 of the first section, and the first concrete. The short-term shear allowable stress τ1 of the Since the root length Lr1 of the first node is 230 mm or more and 300 mm or less, the protrusion height Lh1 of the first node is 50 mm, and the pitch of at least two first nodes is 1 m . The contact area between the first main body and the first node (the area at the base of the node) is sufficiently secured, and the shear strength of the first node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the first section pile, the shearing force of the first section is larger than the shearing force acting on the first section.
Further, according to the above configuration (4), in the first section pile, the length Lt1 of the head of the first section, the length Lr1 of the root of the first section, and the protruding height of the first section. After Lh1 satisfies a predetermined relationship, the length Lt1 of the head of the first node is 130 mm or more and 200 mm or less, and the length Lt1 of the head of the first node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the first section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
On the other hand, according to the above configuration (4), in the second section pile, the length Lr2 at the base of the second section, the outer diameter Dp2 of the second main body, the protruding height Lh2 of the second section, and the second. 2 Short-term shear tolerance of concrete τ2 satisfies the predetermined relationship, and the second node has a shear capacity larger than the short-term maximum pile peripheral friction bearing capacity per pitch of at least two second nodes. The length Lr2 at the base of the second node is 300 mm, the protrusion height Lh2 of the second node is 100 mm, and the pitch of at least two second nodes is 1 m . 2 The contact area between the main body and the second node (the area at the base of the node) is sufficiently secured, and the shear strength of the second node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the second section pile, the shearing force of the second section is larger than the shearing force acting on the second section.
Further, according to the above configuration (4), in the second section pile, the length Lt2 of the head of the second section, the length Lr2 of the root of the second section, and the protruding height of the second section. After Lh2 satisfies a predetermined relationship, the length Lt2 of the head of the second node is 100 mm, and the length Lt2 of the head of the second node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the second section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
Thus, according to the above configuration (4), even in the entire joint pile composed of the first section pile and the second section pile, the contact area between the first main body portion and the first section portion and the second main body portion and the first Sufficient contact area with the 2nd section is secured, and even when the short-term maximum pile peripheral surface friction bearing force acts on the joint pile, the 1st section is more than the shearing force acting on the 1st and 2nd sections. And the shear strength of the second section is large.
Further, according to the above configuration (4), even for the entire joint pile composed of the first section pile and the second section pile, short-term pile peripheral friction based on the outer diameters of the first section and the second section. The bearing capacity can be set, and a short-term pile peripheral surface friction bearing capacity of a desired size can be realized.
Further, according to the above configuration (4), since the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion, the horizontal bearing capacity of the first section pile is made larger than that of the second section pile. Can be done.

(5) The knot pile according to at least one embodiment of the present invention is
In a knot pile provided with a first portion and a second portion integrally connected to the first portion.
The first part is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body and the first section contain concrete and contain concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear stress tolerance of the concrete is τ,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two first nodes. Greater than bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ × Dp1)
Satisfy the relationship shown in
The second part is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body and the second section include the concrete and contain the concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
When the protrusion height of the second node portion from the second main body portion in the radial direction of the second main body portion is Lh2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second node is determined by the root area of the second node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two second nodes. Greater than bearing capacity ,
The length Lr2 at the base of the second node is 300 mm.
The length Lt2 of the head of the second node is 100 mm, and the length Lt2 is 100 mm.
The protruding height Lh2 of the second node is 100 mm, and the protrusion height Lh2 is 100 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ × Dp2)
Satisfy the relationship shown in
The outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion.

According to the above configuration (5), in the first portion, the length Lr1 at the base of the first node, the outer diameter Dp1 of the first main body, the protruding height Lh1 of the first node, and the short-term shearing of concrete. After the allowable stress τ satisfies a predetermined relationship, the first node has a shear strength larger than the short-term maximum pile peripheral friction bearing capacity per pitch of at least two first nodes, and the first Since the length Lr1 at the base of the node is 230 mm or more and 300 mm or less, the protrusion height Lh1 of the first node is 50 mm, and the pitch of at least two first nodes is 1 m , the first main body. The contact area between the portion and the first node (the area at the base of the node) is sufficiently secured, and the shear strength of the first node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the first portion, the shearing force of the first node is larger than the shearing force acting on the first node.

Further, according to the above configuration (5), in the first part, the length Lt1 of the head of the first section, the length Lr1 of the root of the first section, and the protruding height Lh1 of the first section. The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less, and the length Lt1 of the head of the first node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the first section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
On the other hand, according to the above configuration (5), in the second portion, the length Lr2 at the base of the second node, the outer diameter Dp2 of the second main body, the protruding height Lh2 of the second node, and the concrete. With the short-term shear tolerance τ satisfying the predetermined relationship, the second node has a shear bearing capacity greater than the short-term maximum pile peripheral friction bearing capacity per pitch of at least two second nodes. Since the root length Lr2 of the second node is 300 mm, the protrusion height Lh2 of the second node is 100 mm, and the pitch of at least two second nodes is 1 m , the second main body portion The contact area between the and the second node (the area at the base of the node) is sufficiently secured, and the shear strength of the second node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the second portion, the shearing force of the second node is larger than the shearing force acting on the second node.
Further, according to the above configuration (5), in the second part, the length Lt2 of the head of the second section, the length Lr2 of the root of the second section, and the protruding height Lh2 of the second section. The length Lt2 of the head of the second node is 100 mm, and the length Lt2 of the head of the second node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the second section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
Thus, according to the above configuration (5), the contact area between the first main body portion and the first node portion and the second main body portion and the second section of the entire knot pile composed of the first portion and the second portion also. Sufficient contact area with the parts is secured, and even when the short-term maximum pile peripheral friction bearing force acts on the knot pile, the first knot part and the first knot part and the second part are larger than the shear force acting on the first knot part and the second knot part. The shear resistance of each of the two nodes is large.
Further, according to the above configuration (5), the short-term pile peripheral friction bearing capacity of the entire joint pile composed of the first portion and the second portion is also based on the outer diameters of the first node portion and the second node portion. Can be set, and a short-term pile peripheral friction bearing capacity of a desired size can be realized.
Further, according to the above configuration (5), since the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion, the horizontal bearing capacity of the first portion can be made larger than that of the second portion. ..

(6) The joint pile according to at least one embodiment of the present invention is
In a joint pile provided with a first section pile and a second section pile connected to the first section pile.
The first section pile is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body portion and the first section portion include the first concrete, and the first main body portion and the first section portion include the first concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear allowable stress of the first concrete is τ1,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the allowable short-term shear stress of the first concrete, and the short-term maximum pile circumference per pitch of at least two first nodes. Greater than surface friction bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ1 × Dp1)
Satisfy the relationship shown in
The second section pile is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body portion and the second section portion include the second concrete, and the second main body portion and the second section portion include the second concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
Let Lh2 be the height of protrusion of the second node from the second main body in the radial direction of the second main body.
When the short-term shear allowable stress of the second concrete is τ2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second section is determined by the root area of the second section and the allowable short-term shear stress of the second concrete, and the short-term maximum pile circumference per pitch of at least two second sections. Greater than surface friction bearing capacity ,
The length Lr2 at the base of the second node is 230 mm or more and 300 mm or less.
The length Lt2 of the head of the second node is 130 mm or more and 200 mm or less.
The protruding height Lh2 of the second node is 50 mm, and the protrusion height Lh2 is 50 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ2 × Dp2)
Satisfy the relationship shown in
The outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion.

According to the above configuration (6), in the first section pile, the length Lr1 at the base of the first section, the outer diameter Dp1 of the first main body, the protruding height Lh1 of the first section, and the first concrete. The short-term shear allowable stress τ1 of the Since the root length Lr1 of the first node is 230 mm or more and 300 mm or less, the protrusion height Lh1 of the first node is 50 mm, and the pitch of at least two first nodes is 1 m . The contact area between the first main body and the first node (the area at the base of the node) is sufficiently secured, and the shear strength of the first node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the first section pile, the shearing force of the first section is larger than the shearing force acting on the first section.
Further, according to the above configuration (6), in the first section pile, the length Lt1 of the head of the first section, the length Lr1 of the root of the first section, and the protruding height of the first section. After Lh1 satisfies a predetermined relationship, the length Lt1 of the head of the first node is 130 mm or more and 200 mm or less, and the length Lt1 of the head of the first node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the first section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
On the other hand, according to the above configuration (6), in the second section pile, the length Lr2 at the base of the second section, the outer diameter Dp2 of the second main body, the protruding height Lh2 of the second section, and the second. 2 Short-term shear tolerance of concrete τ2 satisfies the predetermined relationship, and the second node has a shear capacity larger than the short-term maximum pile peripheral friction bearing capacity per pitch of at least two second nodes. The root length Lr2 of the second node is 230 mm or more and 300 mm or less, the protrusion height Lh2 of the second node is 50 mm, and the pitch of at least two second nodes is 1 m. Therefore, the contact area between the second main body and the second node (the area at the base of the node) is sufficiently secured, and the shear strength of the second node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the second section pile, the shearing force of the second section is larger than the shearing force acting on the second section.
Further, according to the above configuration (6), in the second section pile, the length Lt2 of the head of the second section, the length Lr2 of the root of the second section, and the protruding height of the second section. After Lh2 satisfies a predetermined relationship, the length Lt2 of the head of the second node is 130 mm or more and 200 mm or less, and the length Lt2 of the head of the second node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the second section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
Thus, according to the above configuration (6), even in the entire joint pile composed of the first section pile and the second section pile, the contact area between the first main body portion and the first section portion and the second main body portion and the first Sufficient contact area with the 2nd section is secured, and even when the short-term maximum pile peripheral surface friction bearing force acts on the joint pile, the 1st section is more than the shearing force acting on the 1st and 2nd sections. And the shear strength of the second section is large.
Further, according to the above configuration (6), even for the entire joint pile composed of the first section pile and the second section pile, short-term pile peripheral friction based on the outer diameters of the first section and the second section. The bearing capacity can be set, and a short-term pile peripheral surface friction bearing capacity of a desired size can be realized.
Further, according to the above configuration (6), since the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion, the horizontal bearing capacity of the first section pile is made larger than that of the second section pile. Can be done.

(7) The knot pile according to at least one embodiment of the present invention is
In a knot pile provided with a first portion and a second portion integrally connected to the first portion.
The first part is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body and the first section contain concrete and contain concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear stress tolerance of the concrete is τ,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two first nodes. Greater than bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ × Dp1)
Satisfy the relationship shown in
The second part is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body and the second section include the concrete and contain the concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
When the protrusion height of the second node portion from the second main body portion in the radial direction of the second main body portion is Lh2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second node is determined by the root area of the second node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two second nodes. Greater than bearing capacity ,
The length Lr2 at the base of the second node is 230 mm or more and 300 mm or less.
The length Lt2 of the head of the second node is 130 mm or more and 200 mm or less.
The protruding height Lh2 of the second node is 50 mm, and the protrusion height Lh2 is 50 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ × Dp2)
Satisfy the relationship shown in
The outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion.

According to the above configuration (7), in the first portion, the length Lr1 at the base of the first node, the outer diameter Dp1 of the first main body, the protruding height Lh1 of the first node, and the short-term shearing of concrete. After the allowable stress τ satisfies a predetermined relationship, the first node has a shear strength larger than the short-term maximum pile peripheral friction bearing capacity per pitch of at least two first nodes, and the first Since the length Lr1 at the base of the node is 230 mm or more and 300 mm or less, the protrusion height Lh1 of the first node is 50 mm, and the pitch of at least two first nodes is 1 m , the first main body. The contact area between the portion and the first node (the area at the base of the node) is sufficiently secured, and the shear strength of the first node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the first portion, the shearing force of the first node is larger than the shearing force acting on the first node.
Further, according to the above configuration (7), in the first part, the length Lt1 of the head of the first section, the length Lr1 of the root of the first section, and the protruding height Lh1 of the first section. The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less, and the length Lt1 of the head of the first node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the first section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
On the other hand, according to the above configuration (7), in the second portion, the length Lr2 at the base of the second node, the outer diameter Dp2 of the second main body, the protruding height Lh2 of the second node, and the concrete. With the short-term shear tolerance τ satisfying the predetermined relationship, the second node has a shear bearing capacity greater than the short-term maximum pile peripheral friction bearing capacity per pitch of at least two second nodes. The root length Lr2 of the second node is 230 mm or more and 300 mm or less, the protrusion height Lh2 of the second node is 50 mm, and the pitch of at least two second nodes is 1 m . 2 The contact area between the main body and the second node (the area at the base of the node) is sufficiently secured, and the shear strength of the second node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force acts on the second portion, the shearing force of the second node is larger than the shearing force acting on the second node.
Further, according to the above configuration (7), in the second part, the length Lt2 of the head of the second section, the length Lr2 of the root of the second section, and the protruding height Lh2 of the second section. The length Lt2 of the head of the second node is 130 mm or more and 200 mm or less, and the length Lt2 of the head of the second node is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force can be set based on the outer diameter of the second section, and the short-term pile peripheral surface friction bearing force of a desired size can be realized.
Thus, according to the above configuration (7), the contact area between the first main body portion and the first node portion and the second main body portion and the second section of the entire knot pile composed of the first portion and the second portion also. Sufficient contact area with the parts is secured, and even when the short-term maximum pile peripheral friction bearing force acts on the knot pile, the first knot part and the first knot part and the second part are larger than the shear force acting on the first knot part and the second knot part. The shear resistance of each of the two nodes is large.
Further, according to the above configuration (7), the short-term pile peripheral friction bearing capacity of the entire joint pile composed of the first portion and the second portion is also based on the outer diameters of the first node portion and the second node portion. Can be set, and a short-term pile peripheral friction bearing capacity of a desired size can be realized.
Further, according to the above configuration (7), since the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion, the horizontal bearing capacity of the first portion can be made larger than that of the second portion. ..

According to at least one embodiment of the present invention, even when the short-term maximum pile peripheral friction bearing force acts on the knot pile, the knot pile and the joint pile having a shear strength of the knot portion larger than the shear force acting on the knot portion are formed. Provided.

It is a figure which shows the state which the knot pile which concerns on one Embodiment of this invention is buried in the ground together with a straight pile. It is a side view schematically showing the joint pile which was formed by connecting the joint piles in FIG. 1 to each other. It is a figure which shows the knot pile in FIG. 1, the left half is a side view, and the right half is a sectional view. It is a schematic enlarged view of the region IV in FIG. It is a figure which shows the knot pile in FIG. 1, the left half is a side view, and the right half is a sectional view. It is a schematic enlarged view of the region VI in FIG. It is a schematic enlarged view of the area VII of FIG. 2, the left half is a side view, and the right half is a sectional view. It is a figure for demonstrating the pile peripheral friction bearing force (short-term pile peripheral friction bearing force) R1 acting on a foundation pile in a short time, and the shearing force acting on a node. It is a side view which shows roughly the node pile which concerns on one Embodiment of this invention. It is a side view which shows roughly the joint pile which concerns on one Embodiment of this invention. It is a figure which shows schematic the 2nd section pile used for the joint pile of FIG. 10, the left half is a side view, and the right half is a sectional view. It is an enlarged view of the region XII in FIG. It is a side view which shows roughly the node pile which concerns on one Embodiment of this invention. In the knot piles of Examples and Comparative Examples, the outer diameter of the knot, the outer diameter of the main body, the concrete design standard strength, the shear strength of the knot, the short-term maximum pile peripheral friction bearing capacity, and F1 are larger than Rmax. It is a table showing whether or not.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. do not have.
For example, expressions that represent relative or absolute arrangements such as "in one direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, the expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or a chamfer within the range where the same effect can be obtained. It shall also represent the shape including the part and the like.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions excluding the existence of other components.

FIG. 1 is a diagram schematically showing a state in which knot piles 2a and 2b according to an embodiment of the present invention are buried in the ground 6 together with straight piles 4. FIG. 2 is a side view schematically showing a joint pile 8a configured by connecting the joint piles 2a and 2b to each other. FIG. 3 is a diagram schematically showing a knot pile 2a, the left half is a side view, and the right half is a cross-sectional view. FIG. 4 is a schematic enlarged view of region IV in FIG. FIG. 5 is a diagram schematically showing a knot pile 2b, the left half is a side view, and the right half is a cross-sectional view. FIG. 6 is a schematic enlarged view of the region VI in FIG. FIG. 7 is a schematic enlarged view of the region VII of FIG. 2, the left half is a side view and the right half is a cross-sectional view.

As shown in FIG. 1, the two knot piles 2a and 2b and the straight pile 4 are connected in series to form one joint pile 10. The joint pile 10 can support a superstructure (not shown).

More specifically, the joint pile 10 is sunk inside the pile hole 11 previously excavated in the ground 6. A root hardening liquid is injected into the bottom of the pile hole 11 and the root hardening liquid is hardened to form a root hardening portion 12 surrounding the lower end portion of the joint pile 10. Further, above the bottom of the pile hole 11, the pile peripheral liquid is injected and the pile peripheral liquid is hardened, so that the pile peripheral portion 14 surrounding the joint pile 10 is formed. The joint pile 10 is supported by the ground 6 via the root consolidation portion 12 and the pile peripheral portion 14. The rooting liquid and the pile peripheral liquid each contain a cement component, and the cement component is mixed with the earth and sand generated by the excavation of the ground 6 and then hardened to form the root hardening portion 12 and the pile peripheral portion 14, respectively. To. The joint piles 2a and 2b, the straight pile 4, the root consolidation portion 12, and the pile peripheral portion 14 constitute one foundation pile 15.

As shown in FIGS. 3 and 4, the knot pile 2a has a main body portion (shaft portion) 16a and at least one knot portion 18a integrally formed with the main body portion 16a. The main body portion 16a and the knot portion 18a are made of concrete. The main body 16 has a cylindrical shape. An annular end plate 20a may be fixed to each upper and lower end surface of the main body portion 16, or a PC steel rod 22a may be bridged between the end plates 20a so as to penetrate the first main body portion 16a. .. Further, the outer peripheral surfaces of both ends of the main body 16a may be covered with a metal cylindrical cover 24a, and a spiral or linear reinforcing bar (not shown) is embedded inside the main body 16a. May be.

The first section 18a protrudes in the radial direction of the first main body 16a from the cylindrical outer peripheral surface 26a of the first main body 16a. The first section 18a has a ring shape so as to surround a part of the outer peripheral surface 26a of the first main body 16a. The first node portion 18a has, for example, a cylindrical outer peripheral surface 28a, and the outer peripheral surface 26a of the first main body portion 16a and the outer peripheral surface 28a of the first node portion 18a are arranged concentrically. Further, the first knot portion 18a has tapered stepped surfaces 30a on both sides in the axial direction of the first main body portion 16a, and the outer peripheral surface 26a of the first main body portion 16a and the outer peripheral surface of the first knot portion 18a. The 28a are connected via the stepped surface 30a. For example, the angle θa formed by the outer peripheral surface 26 and the stepped surface 30a of the first main body portion 16a is 30 ° to 60 °, preferably 45 °.

In the knot pile 2a, the length of the base of the knot 18a on the main body 16a side in the axial direction of the main body 16a is Lr, and the knot 18a on the opposite side of the main body 16a in the axial direction of the main body 16a. The length of the head is Lt, the outer diameter of the main body 16a is Dp, the protrusion height of the knot 18a from the main body 16a in the radial direction of the main body 16a is Lh, and the short-term shear allowable stress of concrete is set. When τ is used, the following two equations:
Lr> 380 × (Dp + 2 × Lh) / (τ × Dp)
Lr-2 × (3 ^ 0.5) × Lh ≦ Lt ≦ Lr-2 / (3 ^ 0.5) × Lh
The relationships indicated by are satisfied respectively.
Further, assuming that the outer diameter of the node 18a is Dn, the protrusion height Lh is expressed by the following equation: Lh = (Dn−Dp) / 2.

In this specification, the knot pile 2a, the main body 16a, and the knot 18a are also referred to as the first knot pile 2a, the first main body 16a, and the first knot 18a, respectively, and the first main body 16a and the first knot 18a are referred to. The concrete constituting 18a is also referred to as a first concrete. The length Lr at the base of the first node 18a on the first main body 16a side is also referred to as Lr1, the length Lt of the head of the first node 18a is also referred to as Lt1, and the outer diameter of the first main body 16a. Dp is also referred to as Dp1, the outer diameter Dn of the first node 18a is also referred to as Dn1, the protrusion height Lh of the first node 18a is also referred to as Lh1, and the short-term shear allowable stress τ of the first concrete is also referred to as τ1.

As shown in FIGS. 5 and 6, the knot pile 2b has a main body portion (shaft portion) 16b and at least one knot portion 18b integrally formed with the main body portion 16b. The main body portion 16b and the knot portion 18b are made of concrete. The main body 16b has a cylindrical shape. An annular end plate 20b may be fixed to each upper and lower end surface of the main body portion 16b, or a PC steel rod 22b may be bridged between the end plates 20b so as to penetrate the main body portion 16b. Further, the outer peripheral surfaces of both ends of the main body 16b may be covered with a metal cylindrical cover 24b, and a spiral or linear reinforcing bar (not shown) is embedded inside the main body 16b. May be.

The second section 18b protrudes in the radial direction of the second main body 16b from the cylindrical outer peripheral surface 26b of the second main body 16b. The second section 18b has a ring shape so as to surround a part of the outer peripheral surface 26b of the second main body 16b. The second node portion 18b has, for example, a cylindrical outer peripheral surface 28b, and the outer peripheral surface 26b of the second main body portion 16b and the outer peripheral surface 28b of the second node portion 18b are arranged concentrically. Further, the second knot portion 18b has tapered stepped surfaces 30b on both sides in the axial direction of the second main body portion 16b, and the outer peripheral surface 26b of the second main body portion 16b and the outer peripheral surface of the second knot portion 18b. The 28b is connected via the stepped surface 30b. For example, the angle θb formed by the outer peripheral surface 26b and the stepped surface 30b of the second main body portion 16b is 30 ° to 60 °, preferably 45 °.

In the knot pile 2b, the length of the root of the knot 18b on the main body 16b side in the axial direction of the main body 16b is Lr, and the knot 18b on the opposite side of the main body 16b in the axial direction of the main body 16b. The length of the head is Lt, the outer diameter of the main body 16b is Dp, the protrusion height of the knot 18b from the main body 16b in the radial direction of the main body 16b is Lh, and the short-term shear allowable stress of concrete is set. When τ is used, the following two equations:
Lr> 380 × (Dp + 2 × Lh) / (τ × Dp)
Lr-2 × (3 ^ 0.5) × Lh ≦ Lt ≦ Lr-2 / (3 ^ 0.5) × Lh
The relationships indicated by are satisfied respectively.
Further, assuming that the outer diameter of the node 18b is Dn, the protrusion height Lh is expressed by the following equation: Lh = (Dn−Dp) / 2.

In this specification, the knot pile 2b, the main body 16b, and the knot 18b are also referred to as the second knot 2b, the second main body 16b, and the second knot 18b, respectively, and the second main body 16b and the second knot 18b are referred to. The concrete constituting 18b is also referred to as a second concrete. The length Lr at the base of the second node 18b on the second main body 16b side is also referred to as Lr2, the length Lt of the head of the second main body 18b is also referred to as Lt2, and the outer diameter of the second main body 16b. Dp is also referred to as Dp2, the outer diameter Dn of the second section 18b is also referred to as Dn2, the protrusion height Lh of the second section 18b is also referred to as Lh2, and the short-term shear allowable stress τ of the second concrete is also referred to as τ2.
Further, in the present specification, the knot piles 2a and 2b, the main body portions 16a and 16b, the knot portions 18a and 18b and the angles θa and θb are collectively referred to as the knot pile 2, the main body portion 16, the knot portion 18 and the angle θ, respectively. ..

FIG. 7 schematically shows an example of a joint device 32 for connecting the knot pile 2a and the knot pile 2b. The fitting device 32 has an inner ring 34 and an outer ring 36.
The inner ring 34 has an annular portion 38 surrounding the ends of the knot pile 2a and the knot pile 2b, and two annular protrusions 40 protruding inward in the radial direction from the inner peripheral surface of the annular portion 38. Circumferential grooves 42a and 42b are formed at the ends of the joint piles 2a and the joint piles 2b adjacent to the end plates 20a and 20b, and the inner ring 34 has an annular projection 40 so as to mesh with the circumferential grooves 42a and 42b. Placed in. In order to enable such an arrangement, the inner ring 34 is composed of two half-split members 34a and 34b.

The outer ring 36 is fitted to the outside of the inner ring 34. Here, the outer peripheral surface of the inner ring 34 is formed of an inclined surface inclined with respect to the axial direction of the inner ring 34, and the inner peripheral surface of the outer ring 36 is also formed of an inclined surface inclined with respect to the axial direction of the outer ring 36. Has been done. The outer ring 36 is fitted to the inner ring 34 while rubbing the inclined surfaces against each other, thereby tightening the inner ring 34 by the wedge effect. The outer peripheral surface of the inner ring 34 and the inner peripheral surface of the outer ring 36 are formed with irregularities (not shown), and the meshing of these irregularities prevents the outer ring 36 from falling off from the inner ring 34. ..

Here, FIG. 8 is a diagram for explaining the pile peripheral friction bearing force (short-term pile peripheral friction bearing force) R1 acting on the foundation pile 15 in a short period of time and the shearing force acting on the node 18. As shown in FIG. 8, the short-term pile peripheral surface friction bearing force R1 is transmitted to the knot portion 18 via the pile peripheral portion 14, and a shear force is generated in the knot portion 18. Therefore, it is desirable that the shear strength F1 of the node 18 is larger than the maximum value of the assumed short-term pile peripheral friction bearing force R1 (short-term maximum pile peripheral friction bearing force Rmax) (F1> Rmax).

Hereinafter, the above desired conditions (F1> Rmax) will be examined.
The short-term pile peripheral friction bearing capacity R1 is calculated by the following equation:
R1 = 2/3 x Nave x β x Ls x φ ... (1)
It is represented by.
In the above formula (1), Nave is an average value of N values obtained by a standard penetration test in the ground 6 around the knot pile 2. However, when Nave> 30, Nave = 30.
β is a coefficient of frictional force on the peripheral surface of the pile in sandy / gravel ground, and is represented by β = 9.5ω when the peripheral liquid of the pile is an expansion type.
ω is expressed by the following equation: ω = De / Ds, and is 1.0 to 2.0.
De is the excavation diameter (enlarged excavation diameter) of the pile hole 11.
Ds is expressed by the following equation: Ds = Dn + 0.05, where the outer diameter of the node 18 is Dn.
Ls is the length in contact with the ground 6.
φ is the perimeter of the node 18, and the following equation:
φ = π × Dn ・ ・ ・ (2)
It is represented by.
When the pitch Lp of the node 18 is 1 m, the short-term maximum pile peripheral friction bearing capacity Rmax per 1 m is obtained by substituting Nave = 30, β = 9.5 × 2.0, and Ls = 1 into equation (1). By doing, the following equation:
Rmax = 2/3 × 30 × 9.5 × 2 × 1.0 × φ ・ ・ ・ (3)
It is represented by.

On the other hand, according to the Architectural Institute of Japan "Reinforced Concrete Structural Calculation Criteria / Explanation", the short-term shear stress tolerance τ of concrete is as follows:
τ = (0.49 + Fc / 100) × K ・ ・ ・ (4)
Is sought after.
In the above formula, Fc is a concrete design reference strength (unit: N / mm ² ), and K is a constant (1.5 or 2.0). In this embodiment, K = 1.5.
Assuming that the contact area between the knot 18 and the main body 16 (knot root area) is A1 (unit: mm ² ), A1 is expressed by the following equation:
A1 = Lr × π × Dp ・ ・ ・ (5)
It is represented by.
The shear strength F1 (unit: kN) of the node 18 is the following equation:
F1 = (τ × A1) / 1000 ... (6)
It is represented by.

In order for the shear strength F1 of the node 18 to be larger than the short-term maximum pile peripheral friction bearing capacity Rmax, the following equation:
F1> Rmax ・ ・ ・ (7)
Must be met. Therefore, by substituting the equations (3) to (6) into the equation (7), the following equation:
Lr> 380 × (Dp + 2 × Lh) / (τ × Dp) ・ ・ ・ (8)
Is obtained.

On the other hand, since the angle θ is 30 ° or more and 60 ° or less, the following equation:
Lr-2 × (3 ^ 0.5) × Lh ≦ Lt ≦ Lr-2 / (3 ^ 0.5) × Lh ... (9)
Is obtained.

In the knot pile 2 (2a, 2b) having the above configuration, the length Lr at the base of the knot 18, the outer diameter Dp of the main body 16, the protruding height Lh of the knot 18, and the short-term shear allowable stress of concrete τ However, the predetermined relationship represented by the above formula (8) is satisfied. Therefore, the contact area between the main body 16 and the node 18 (the area at the base of the node) is sufficiently secured, and the shear strength F1 of the node 18 is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the knot pile 2, the shear force F1 of the knot portion is larger than the shear force acting on the knot portion 18.
Further, in the knot pile 2 (2a, 2b) having the above configuration, the length Lt of the head of the knot portion 18, the length Lr of the root of the knot portion 18, and the protruding height Lh of the knot portion 18 are the above equations. The predetermined relationship represented by (9) is satisfied, and the length Lt of the head of the node 18 is sufficiently secured. Therefore, the short-term pile peripheral surface friction bearing force R1 can be set based on the outer diameter of the knot portion 18, and the short-term pile peripheral surface friction bearing force R1 having a desired size can be realized.

In some embodiments, the root length Lr of the node 18 is 230 mm or more and 300 mm or less, the head length Lt of the node 18 is 130 mm or more and 200 mm or less, and the protrusion height Lh of the node 18 is Is 50 mm.
According to the above configuration, the root length Lr of the node 18 is 230 mm or more and 300 mm or less, and the protrusion height Lh of the node 18 is 50 mm, so that the contact area between the main body 16 and the node 18 is sufficient. The shear strength F1 of the node 18 is sufficiently secured.
Further, according to the above configuration, the length Lt of the head of the node 18 is 130 mm or more and 200 mm or less, and the length Lt of the head of the node 18 is sufficiently secured.

In some embodiments, the root length Lr of the node 18 is 300 mm, the head length Lt of the node 18 is 200 mm, and the protruding height Lh of the node 18 is 50 mm.
According to the above configuration, since the length Lr at the base of the node 18 is 300 mm and the protruding height Lh of the node 18 is 50 mm, a sufficient contact area between the main body 16 and the node 18 is secured. , The shear strength F1 of the node 18 is sufficiently secured.
Further, according to the above configuration, the length Lt of the head of the node 18 is 200 mm, and the length Lt of the head of the node 18 is sufficiently secured.

In some embodiments, the outer diameter Dp of the main body 16 is 600 mm or more and 1400 mm or less.
In some embodiments, the root length Lr of the node 18 is 400 mm or less, preferably 300 mm or less.
In some embodiments, the pitch Lp of the node 18 is 500 mm or more and 1200 mm or less, preferably 1000 mm.
In some embodiments, the concrete design reference strength Fc is 85 N / mm ² or more and 123 N / mm ² or less, for example 85 N / mm ² , 105 N / mm ² , or 123 N / mm ² . The concrete design standard strength Fc is preferably 85 N / mm ² .

In some embodiments, the protruding height Lh of the node 18 is 40 mm or more and 100 mm or less, preferably 40 mm or more and 60 mm or less, and more preferably 50 mm.
In some embodiments, the knot pile 2 is a hollow ready-made pile, which is a high-strength prestressed concrete pile (PHC pile), but is a reinforced concrete pile (RC pile) or a high-strength prestressed reinforced concrete pile (PRC pile). There may be.

In some embodiments, the outer diameter Dp of the main body 16 of the knot pile 2 may be constant except for the knot 18 (standard type), but the outer diameter of one end of the knot pile 2 is the knot pile. It may be larger than the outer diameter Dp of the main body 16 at the center or the other end of 2. For example, the outer diameter of one end of the knot pile 2 may be larger than the outer diameter Dp of the main body 16 at the center or the other end of the knot pile 2 and smaller than the outer diameter Dn of the knot 18 (head expansion). It may be the same as the outer diameter Dn of the node 18 (intermediate diameter type) (head expansion type).

Hereinafter, the joint pile 8a according to the embodiment of the present invention will be described.
As shown in FIG. 2, the joint pile 8a includes the first section pile 2a and the second section pile 2b described above, respectively, and the first section pile 2a and the second section pile 2b are provided by, for example, a joint device 32. They are interconnected.
Specifically, the first section pile 2a has the following two equations:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ1 × Dp1)
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Each of the relationships shown in is satisfied.
The root length Lr1 of the first node 18a is 230 mm or more and 300 mm or less, the head length Lt1 of the first node 18a is 130 mm or more and 200 mm or less, and the protruding height of the first node 18a is Lh1 is 50 mm.
On the other hand, as described above, the second section pile 2b has the following two equations:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ2 × Dp2)
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Each of the relationships shown in is satisfied.
The root length Lr2 of the second node 18b is 230 mm or more and 300 mm or less, the head length Lt2 of the second node 18b is 130 mm or more and 200 mm, and the protruding height Lh2 of the second node 18b is Is 50 mm.
Further, in the joint pile 8a, the outer diameter Dp1 of the first main body portion 16a is larger than the outer diameter Dp2 of the second main body portion 16b.
Further, the outer diameter Dn1 of the first section 18a is larger than the outer diameter Dn2 of the second section 18b (Dn1> Dn2), and the height Lh1 of the first section 18a is the height Lh1 of the second section 18b. Equal (Lh1 = Lh2).
In this embodiment, Dn1> Dn2 is set, but Dn1 ≦ Dn2 may be set.

According to the above-mentioned joint pile 8a, in the first section pile 2a, the length Lr1 at the base of the first section 18a, the outer diameter Dp1 of the first main body 16a, the protruding height Lh1 of the first section 18a, and , The short-term shear allowable stress τ1 of the first concrete satisfies a predetermined relationship, the root length Lr1 of the first node 18a is 230 mm or more and 300 mm or less, and the protrusion height Lh1 of the first node 18a. Is 50 mm, so that the contact area between the first main body portion 16a and the first node portion 18a (the area at the base of the node portion) is sufficiently secured, and the shear strength F1 of the first node portion 18a is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the first section pile 2a, the shearing force F1 of the first section 18a is larger than the shearing force acting on the first section 18a.

Further, according to the above-mentioned joint pile 8a, in the first section pile 2a, the length Lt1 of the head of the first section 18a, the length Lr1 of the root of the first section 18a, and the first section 18a. The protrusion height Lh1 of the first section 18a satisfies the predetermined relationship, the head length Lt1 of the first section 18a is 130 mm or more and 200 mm or less, and the head length Lt1 of the first section 18a is sufficient. Secured. Therefore, the short-term pile peripheral friction bearing force R1 can be set based on the outer diameter Dn1 of the first section 18a, and the short-term pile peripheral friction bearing force R1 of a desired size can be realized.

On the other hand, according to the above-mentioned joint pile 8a, in the second section pile 2b, the length Lr2 at the base of the second section 18b, the outer diameter Dp2 of the second main body 16b, and the protruding height Lh2 of the second section 18b. , And, after the short-term shear stress tolerance τ2 of the second concrete satisfies a predetermined relationship, the root length Lr2 of the second node 18b is 230 mm or more and 300 mm or less, and the protrusion height of the second node 18b. Since Lh2 is 50 mm, the contact area between the second main body portion 16b and the second node portion 18b (the area at the base of the node portion) is sufficiently secured, and the shear strength F1 of the second node portion 18b is sufficiently secured. .. As a result, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the second section pile 2b, the shearing force F1 of the second section portion is larger than the shearing force acting on the second section portion 18b.

Further, according to the above-mentioned joint pile 8a, in the second section pile 2b, the length Lt2 of the head of the second section 18b, the length Lr2 of the root of the second section 18b, and the second section 18b. The protrusion height Lh2 of the second section 18b satisfies the predetermined relationship, the head length Lt2 of the second section 18b is 130 mm or more and 200 mm or less, and the head length Lt2 of the second section 18b is sufficient. Secured. Therefore, the short-term pile peripheral friction bearing force R1 can be set based on the outer diameter Dp2 of the second node 18b, and the short-term pile peripheral friction bearing force R1 of a desired size can be realized.

Thus, according to the above-mentioned joint pile 8a, the contact area between the first main body portion 16a and the first joint portion 18a and the first joint pile 8a composed of the first joint pile 2a and the second joint pile 2b also as a whole. 2 Even when the contact area between the main body 16b and the second section 18b is sufficiently secured and the short-term maximum pile peripheral surface friction bearing force Rmax acts on the joint pile 8a, the first section 18a and the second section 18b The shearing force F1 of the first node portion 18a and the second node portion 18b is larger than the shearing force acting on the pile.
Further, according to the above-mentioned joint pile 8a, the outer diameters Dp1 and Dp2 of the first section 18a and the second section 18b of the joint pile 8a composed of the first section pile 2a and the second section pile 2b as a whole. The short-term pile peripheral surface friction bearing force R1 can be set based on the above, and the short-term pile peripheral surface friction bearing force R1 having a desired size can be realized.
Further, according to the above-mentioned joint pile 8a, since the outer diameter Dp1 of the first main body portion 16a is larger than the outer diameter Dp2 of the second main body portion 16b, the horizontal bearing capacity of the first section pile 2a is higher than that of the second section pile 2b. Can also be increased.

Hereinafter, the knot pile 2c according to the embodiment of the present invention will be described. In the following description of the embodiment, the same or similar configurations as those of the preceding embodiments are designated by the same reference numerals, and the description thereof will be omitted or simplified.
FIG. 9 is a side view schematically showing the knot pile 2c. The joint pile 2c substantially corresponds to a jointly formed first joint pile 2a and a second joint pile 2b constituting the joint pile 8a.
Specifically, as shown in FIG. 9, the knot pile 2c includes a first portion 44a and a second portion 44b integrally connected to the first portion 44a. The first portion 44a substantially corresponds to the first section pile 2a, and the second portion 44b substantially corresponds to the second section pile 2b.

The first portion 44a has a first main body portion (shaft portion) 16a and at least one first node portion 18a integrally molded with the first main body portion 16a. The first main body portion 16a and the first section portion 18a are made of concrete. The first main body portion 16 has a cylindrical shape.

The first section 18a protrudes in the radial direction of the first main body 16a from the cylindrical outer peripheral surface 26a of the first main body 16a. The first section 18a has a ring shape so as to surround a part of the outer peripheral surface 26a of the first main body 16a. The first node portion 18a has, for example, a cylindrical outer peripheral surface 28a, and the outer peripheral surface 26a of the first main body portion 16a and the outer peripheral surface 28a of the first node portion 18a are arranged concentrically. Further, the first knot portion 18a has tapered stepped surfaces 30a on both sides in the axial direction of the first main body portion 16a, and the outer peripheral surface 26a of the first main body portion 16a and the outer peripheral surface of the first knot portion 18a. The 28a are connected via the stepped surface 30a. For example, the angle θa formed by the outer peripheral surface 26 and the stepped surface 30a of the first main body portion 16a is 30 ° to 60 °, preferably 45 °.

In the first portion 44a, the length of the root of the first node portion 18a on the first main body portion 16a side in the axial direction of the first main body portion 16a is Lr1, and the main body portion 16a in the axial direction of the first main body portion 16a. The length of the head of the first node 18a on the opposite side is Lt1, the outer diameter of the first main body 16a is Dp1, and the first from the first main body 16a in the radial direction of the first main body 16a. When the protruding height of the node 18a is Lh1 and the short-term shear stress tolerance of concrete is τ, the following two equations:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ × Dp1)
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
The relationships indicated by are satisfied respectively.
In the first portion 44a, the root length Lr1 of the first node portion 18a is 230 mm or more and 300 mm or less, and the head length Lt1 of the first node portion 18a is 130 mm or more and 200 mm or less, and the first section. The protruding height Lh1 of the portion 18a is 50 mm.

On the other hand, the second portion 44b has a second main body portion (shaft portion) 16b and at least one second node portion 18b integrally molded with the second main body portion 16b. The second main body portion 16b and the second node portion 18b are made of concrete. The second main body portion 16b has a cylindrical shape.

The second section 18b protrudes in the radial direction of the second main body 16b from the cylindrical outer peripheral surface 26b of the second main body 16b. The second section 18b has a ring shape so as to surround a part of the outer peripheral surface 26b of the second main body 16b. The second node portion 18b has, for example, a cylindrical outer peripheral surface 28b, and the outer peripheral surface 26b of the second main body portion 16b and the outer peripheral surface 28b of the second node portion 18b are arranged concentrically. Further, the second knot portion 18b has tapered stepped surfaces 30b on both sides in the axial direction of the second main body portion 16b, and the outer peripheral surface 26b of the second main body portion 16b and the outer peripheral surface of the second knot portion 18b. The 28b is connected via the stepped surface 30b. For example, the angle θb formed by the outer peripheral surface 26b and the stepped surface 30b of the second main body portion 16b is 30 ° to 60 °, preferably 45 °.

In the second portion 44b, the length of the root of the node 18b on the side of the second main body 16b in the axial direction of the second main body 16b is Lr, and the second main body 16b in the axial direction of the second main body 16b. The length of the head of the second node 18b on the opposite side is Lt2, the outer diameter of the second main body 16b is Dp2, and the second from the second main body 16b in the radial direction of the second main body 16b. When the protruding height of the node 18b is Lh and the short-term shear stress tolerance of concrete is τ, the following two equations:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ × Dp2)
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
The relationships indicated by are satisfied respectively.
Further, the outer diameter Dn1 of the first section 18a is larger than the outer diameter Dn2 of the second section 18b (Dn1> Dn2), and the height Lh1 of the first section 18a is the height Lh1 of the second section 18b. Equal (Lh1 = Lh2).
In this embodiment, Dn1> Dn2 is set, but Dn1 ≦ Dn2 may be set.

In the second portion 44b, the root length Lr2 of the second node 18b is 230 mm or more and 300 mm or less, and the head length Lt2 of the second node 18b is 130 mm or more and 200 mm or less, and the second section. The protruding height Lh2 of the portion 18b is 50 mm.
Further, in the joint pile 2c, the outer diameter Dp1 of the first main body portion 16a is larger than the outer diameter Dp2 of the second main body portion 16b.

The first main body portion 16a and the second main body portion 16b are integrally molded so as to be coaxially connected to each other, and are made of the same concrete.
In addition, annular end plates 20a and 20b may be fixed to the end faces of the first main body portion 16a and the end faces of the second main body portion 16b located at both ends of the joint pile 2c, and between the end plates 20a and 20b. A PC steel rod (not shown) may be bridged through the first main body portion 16a and the second main body portion 16b. Further, the outer peripheral surfaces of the end portions of the first main body portion 16a and the end portions of the second main body portion 16b located at both ends of the joint pile 2c may be covered with metal cylindrical covers 24a and 24b. Although not shown, spiral or linear reinforcing bars may be embedded inside the main body 16a and the second main body 16b.

According to the above-mentioned joint pile 2c, in the first section 44a, the length Lr1 at the base of the first section 18a, the outer diameter Dp1 of the first main body 16a, the protruding height Lh1 of the first section 18a, and After the short-term shear allowable stress τ of the concrete satisfies a predetermined relationship, the root length Lr1 of the first node 18a is 230 mm or more and 300 mm or less, and the protrusion height Lh1 of the first node is 50 mm. Therefore, the contact area between the first main body and the first node (the area at the base of the node) is sufficiently secured, and the shear strength F1 of the first node is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the first portion 44a, the shearing force F1 of the first node portion 18a is larger than the shearing force acting on the first node portion 18a.

Further, according to the above-mentioned knot pile 2c, in the first section 44a, the length Lt1 of the head of the first section 18a, the length Lr1 of the root of the first section 18a, and the first section 18a. After the protrusion height Lh1 satisfies a predetermined relationship, the head length Lt1 of the first node 18a is 130 mm or more and 200 mm or less, and the head length Lt1 of the first node 18a is sufficiently secured. Will be done. Therefore, the short-term pile peripheral friction bearing force R1 can be set based on the outer diameter Dp1 of the first section 18a, and the short-term pile peripheral friction bearing force R1 of a desired size can be realized.

On the other hand, according to the above-mentioned joint pile 2c, in the second section 44b, the length Lr2 at the base of the second section 18b, the outer diameter Dp2 of the second main body 16b, and the protruding height Lh2 of the second section 18b. Further, after the short-term shear allowable stress τ of the concrete satisfies a predetermined relationship, the root length Lr2 of the second node 18b is 230 mm or more and 300 mm or less, and the protrusion height Lh2 of the second node 18b is Since it is 50 mm, the contact area between the second main body portion 16b and the second node portion 18b (the area at the base of the node portion) is sufficiently secured, and the shear strength F1 of the second node portion 18b is sufficiently secured. As a result, even when the short-term pile peripheral surface friction bearing force acts on the second section pile, the shearing force F1 of the second section 18b is larger than the shearing force acting on the second section 18b.

Further, according to the above-mentioned knot pile 2c, in the second section 44b, the length Lt2 of the head of the second section 18b, the length Lr2 of the root of the second section 18b, and the second section 18b. After the protrusion height Lh2 satisfies a predetermined relationship, the head length Lt2 of the second node 18b is 130 mm or more and 200 mm, and the head length Lt2 of the second node 18b is sufficiently secured. To. Therefore, the short-term pile peripheral friction bearing force R1 can be set based on the outer diameter Dp2 of the second node 18b, and the short-term pile peripheral friction bearing force R1 of a desired size can be realized.

Thus, according to the above-mentioned knot pile 2c, the contact area between the first main body portion 16a and the first knot portion 18a and the second main body of the knot pile 2c composed of the first portion 44a and the second portion 44b as a whole. Sufficient contact area between the section 16b and the second section 18b is secured, and even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the knot pile 2c, it acts on the first section 18a and the second section 18b. The shearing force F1 of the first node portion 18a and the second node portion 18b is larger than the shearing force to be applied.
Further, according to the above-mentioned knot pile 2c, the knot pile 2c composed of the first portion 44a and the second portion 44b is also based on the outer diameters Dp1 and Dp2 of the first section 18a and the second section 18b. The short-term pile peripheral surface friction bearing force R1 can be set, and the short-term pile peripheral surface friction bearing force R1 of a desired size can be realized.
Further, according to the above-mentioned knot pile 2c, since the outer diameter Dp1 of the first main body portion 16a is larger than the outer diameter Dp2 of the second main body portion 16b, the horizontal bearing capacity of the first portion 44a is larger than that of the second portion 44b. can do.

Hereinafter, the joint pile 8b according to the embodiment of the present invention will be described. FIG. 10 is a side view schematically showing the joint pile 8b. FIG. 11 is a diagram schematically showing the second section pile 2b used for the joint pile 8b, the left half is a side view, and the right half is a cross-sectional view. FIG. 12 is a schematic enlarged view of region XII in FIG.
The joint pile 8b has a root length Lr2 of the second node 18b of 300 mm, a head length Lt2 of the second node 18b of 100 mm, and a protruding height Lh2 of the second node 18b of 100 mm. It is different from the above-mentioned joint pile 8a in that.
Further, the outer diameter Dp1 of the first main body portion 16a is made larger than the outer diameter Dp1 of the second main body portion 16b (Dp1> Dp2), and the outer diameter Dn1 of the first section portion 18a is changed to the outer diameter Dn2 of the second section portion 18b. Was equal to (Dn1 = Dn2).
In this embodiment, Dn1 = Dn2 is set, but Dn1> Dn2 or Dn1 <Dn2 may be used.

According to the above-mentioned joint pile 8b, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the first section pile 2a, the shear force of the first section 18a is higher than the shear force acting on the first section 18a. F1 is large.
Further, according to the above-mentioned joint pile 8b, in the first section pile 2a, the short-term pile peripheral surface friction bearing force R1 can be set based on the outer diameter Dn1 of the first section portion 18a, and has a desired size. A short-term pile peripheral surface friction bearing force R1 can be realized.

On the other hand, according to the above-mentioned joint pile 8b, in the second section pile 2b, the length Lr2 at the base of the second section 18b, the outer diameter Dp2 of the second main body 16b, and the protruding height Lh2 of the second section 18b. , And, after the short-term shear allowable stress τ2 of the second concrete satisfies a predetermined relationship, the root length Lr2 of the second section 18b is 300 mm, and the protrusion height Lh2 of the second section 18b is Since it is 100 mm, the contact area between the second main body portion 16b and the second node portion 18b (the area at the base of the node portion) is sufficiently secured, and the shear strength F1 of the second node portion 18b is sufficiently secured. As a result, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the second section pile 2b, the shearing force F1 of the second section portion is larger than the shearing force acting on the second section portion 18b.

Further, according to the above-mentioned joint pile 8b, in the second section pile 2b, the length Lt2 of the head of the second section 18b, the length Lr2 of the root of the second section 18b, and the second section 18b. The protrusion height Lh2 of the second section 18b satisfies the predetermined relationship, the head length Lt2 of the second section 18b is 100 mm, and the head length Lt2 of the second section 18b is sufficiently secured. .. Therefore, the short-term pile peripheral friction bearing force R1 can be set based on the outer diameter Dp2 of the second node 18b, and the short-term pile peripheral friction bearing force R1 of a desired size can be realized.

Thus, according to the above-mentioned joint pile 8b, the contact area between the first main body portion 16a and the first joint portion 18a and the first joint pile 8b composed of the first section pile 2a and the second section pile 2b as a whole. 2 Even when the contact area between the main body 16b and the second section 18b is sufficiently secured and the short-term maximum pile peripheral surface friction bearing force Rmax acts on the joint pile 8b, the first section 18a and the second section 18b The shearing force F1 of the first node portion 18a and the second node portion 18b is larger than the shearing force acting on the pile.
Further, according to the above-mentioned joint pile 8b, the outer diameters Dp1 and Dp2 of the first section 18a and the second section 18b of the joint pile 8b composed of the first section pile 2a and the second section pile 2b as a whole. The short-term pile peripheral surface friction bearing force R1 can be set based on the above, and the short-term pile peripheral surface friction bearing force R1 having a desired size can be realized.
Further, according to the joint pile 8b described above, since the outer diameter Dp1 of the first main body portion 16a is larger than the outer diameter Dp2 of the second main body portion 16b, the horizontal bearing capacity of the first section pile 2a is higher than that of the second section pile 2b. Can also be increased.

Hereinafter, the knot pile 2d according to the embodiment of the present invention will be described. FIG. 13 is a side view schematically showing the knot pile 2d.
The knot pile 2d substantially corresponds to one in which the first knot pile 2a and the second knot pile 2b constituting the joint pile 8b are integrally formed. Therefore, the knot pile 2d has a root length Lr2 of the second knot 18b of 300 mm, a head length Lt2 of the second knot 18b of 100 mm, and a protruding height Lh2 of the second knot 18b. Is 100 mm, which is different from the above-mentioned knot pile 2c.
Further, the outer diameter Dp1 of the first main body portion 16a is made larger than the outer diameter Dp1 of the second main body portion 16b (Dp1> Dp2), and the outer diameter Dn1 of the first section portion 18a is changed to the outer diameter Dn2 of the second section portion 18b. Was equal to (Dn1 = Dn2).
In this embodiment, Dn1 = Dn2 is set, but Dn1> Dn2 or Dn1 <Dn2 may be used.

According to the above-mentioned knot pile 2d, even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the first section 44a, the shear force F1 of the first section 18a is higher than the shear force acting on the first section 18a. Is big.
Further, according to the above-mentioned knot pile 2d, in the first section 44a, the short-term pile peripheral surface friction bearing force R1 can be set based on the outer diameter Dp1 of the first section 18a, and a short-term of a desired size can be set. The pile peripheral surface friction bearing force R1 can be realized.

On the other hand, according to the above-mentioned joint pile 2d, in the second section 44b, the length Lr2 at the base of the second section 18b, the outer diameter Dp2 of the second main body 16b, and the protruding height Lh2 of the second section 18b. Further, the short-term shear stress tolerance τ of the concrete satisfies a predetermined relationship, and the root length Lr2 of the second node 18b is 300 mm, and the protrusion height Lh2 of the second node 18b is 100 mm. Therefore, the contact area between the second main body portion 16b and the second node portion 18b (the area at the base of the node portion) is sufficiently secured, and the shear strength F1 of the second node portion 18b is sufficiently secured. As a result, even when the short-term pile peripheral surface friction bearing force acts on the second section pile, the shearing force F1 of the second section 18b is larger than the shearing force acting on the second section 18b.

Further, according to the above-mentioned knot pile 2d, in the second section 44b, the length Lt2 of the head of the second section 18b, the length Lr2 of the root of the second section 18b, and the second section 18b. After the protrusion height Lh2 satisfies a predetermined relationship, the length Lt2 of the head of the second node 18b is 100 mm, and the length Lt2 of the head of the second node 18b is sufficiently secured. Therefore, the short-term pile peripheral friction bearing force R1 can be set based on the outer diameter Dp2 of the second node 18b, and the short-term pile peripheral friction bearing force R1 of a desired size can be realized.

Thus, according to the above-mentioned knot pile 2d, the contact area between the first main body portion 16a and the first knot portion 18a and the second main body of the knot pile 2d composed of the first portion 44a and the second portion 44b as a whole. Sufficient contact area between the section 16b and the second section 18b is secured, and even when the short-term maximum pile peripheral surface friction bearing force Rmax acts on the knot pile 2d, it acts on the first section 18a and the second section 18b. The shearing force F1 of the first node portion 18a and the second node portion 18b is larger than the shearing force to be applied.
Further, according to the above-mentioned knot pile 2d, the knot pile 2d composed of the first portion 44a and the second portion 44b is also based on the outer diameters Dp1 and Dp2 of the first section 18a and the second section 18b. The short-term pile peripheral surface friction bearing force R1 can be set, and the short-term pile peripheral surface friction bearing force R1 of a desired size can be realized.
Further, according to the above-mentioned knot pile 2d, since the outer diameter Dp1 of the first main body portion 16a is larger than the outer diameter Dp2 of the second main body portion 16b, the horizontal bearing capacity of the first portion 44a is larger than that of the second portion 44b. can do.

[Examples and Comparative Examples]
FIG. 14 shows the outer diameter Dn of the knot portion 18, the outer diameter Dp of the main body portion 16, the concrete design standard strength Fc, the shear strength F1 of the knot portion 18, and the short-term maximum pile peripheral friction in the knot piles of Examples and Comparative Examples. It is a table which shows whether or not the bearing capacity Rmax and F1 are larger than Rmax. The shear strength F1 and the short-term maximum pile peripheral friction bearing capacity Rmax of the node 18 are calculated values obtained by the above equations (6) and (3), respectively.
As shown in FIG. 14, when the outer diameter Dn of the knot 18 is 600 mm, the outer diameter Dp of the main body 16 is 500 mm, and the concrete design standard strength Fc is 85 N / mm ² , the length of the root of the knot 18 is It can be seen that when Lr is 230 mm or more, the shear strength F1 of the node 18 becomes larger than the short-term maximum pile peripheral friction bearing force Rmax.

Finally, the present invention is not limited to some of the above-described embodiments, and includes a modified form of the above-mentioned embodiment and a form in which these forms are appropriately combined.

2,2c, 2d Knotted pile 2a 1st knotted pile 2b 2nd knotted pile 4 Straight pile 6 Ground 8a, 8b Jointed pile 10 Jointed pile 11 Pile hole 12 Firming part 14 Pile circumference 15 Foundation pile 16 Main body (shaft part) )
16a 1st main body (shaft)
16b 2nd main body (shaft)
18 Section 18a Section 1 Section 18b Section 2 20a, 20b End plate 22a, 22b PC steel rod 24a, 22b Cover 26a, 26b Outer surface 28a, 28b Outer surface 30a, 30b Step surface 32 Joint device 34 Inner ring 34a , 34b Half-split member 36 Outer ring 38 Circular portion 40 Circular protrusion 42a, 42b Circumferential groove 44a First part 44b Second part

Claims (7)

Cylindrical body and
It is provided with at least two knots protruding from the outer peripheral surface of the main body.
The main body and the knots contain concrete and contain concrete.
Let Lr be the length of the base of the node on the main body side in the axial direction of the main body.
Let Lt be the length of the head of the node on the opposite side of the main body in the axial direction of the main body.
The outer diameter of the main body is Dp.
When the protruding height of the node from the main body in the radial direction of the main body is Lh ,
The following formula:
Lr-2 × (3 ^ 0.5) × Lh ≦ Lt ≦ Lr-2 / (3 ^ 0.5) × Lh
Satisfy the relationship shown in
The outer diameter Dp of the main body is 600 mm or more and 1400 mm or less.
The length Lr at the base of the node is 230 mm or more and 300 mm or less.
The length Lt of the head of the node is 130 mm or more and 200 mm or less.
The protruding height Lh of the node is 40 mm or more and 100 mm or less.
The shear strength of the knot is determined by the root area of the knot and the short-term shear allowable stress of the concrete, and is larger than the short-term maximum pile peripheral friction bearing capacity per pitch of the at least two knots.
A knot pile characterized by that. When the short-term shear stress tolerance of the concrete is τ,
The length Lr at the base of the node is 230 mm or more and 300 mm or less.
The length Lt of the head of the node is 130 mm or more and 200 mm or less.
The protruding height Lh of the node is 50 mm, and the protrusion height Lh is 50 mm.
The pitch of the at least two nodes is 1 m.
The node is
The following formula:
Lr> 380 × (Dp + 2 × Lh) / (τ × Dp)
The knot pile according to claim 1, wherein the relationship indicated by the above is satisfied. The length Lr at the base of the node is 300 mm, and the length is 300 mm.
The length Lt of the head of the node is 200 mm .
The knot pile according to claim 2, characterized in that. In a joint pile provided with a first section pile and a second section pile connected to the first section pile.
The first section pile is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body portion and the first section portion include the first concrete, and the first main body portion and the first section portion include the first concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear allowable stress of the first concrete is τ1,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the allowable short-term shear stress of the first concrete, and the short-term maximum pile circumference per pitch of at least two first nodes. Greater than surface friction bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ1 × Dp1)
Satisfy the relationship shown in
The second section pile is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body portion and the second section portion include the second concrete, and the second main body portion and the second section portion include the second concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
Let Lh2 be the height of protrusion of the second node from the second main body in the radial direction of the second main body.
When the short-term shear allowable stress of the second concrete is τ2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second section is determined by the root area of the second section and the allowable short-term shear stress of the second concrete, and the short-term maximum pile circumference per pitch of at least two second sections. Greater than surface friction bearing capacity ,
The length Lr2 at the base of the second node is 300 mm.
The length Lt2 of the head of the second node is 100 mm, and the length Lt2 is 100 mm.
The protruding height Lh2 of the second node is 100 mm, and the protrusion height Lh2 is 100 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ2 × Dp2)
Satisfy the relationship shown in
A joint pile characterized in that the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion. In a knot pile provided with a first portion and a second portion integrally connected to the first portion.
The first part is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body and the first section contain concrete and contain concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear stress tolerance of the concrete is τ,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two first nodes. Greater than bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ × Dp1)
Satisfy the relationship shown in
The second part is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body and the second section include the concrete and contain the concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
When the protrusion height of the second node portion from the second main body portion in the radial direction of the second main body portion is Lh2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second node is determined by the root area of the second node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two second nodes. Greater than bearing capacity ,
The length Lr2 at the base of the second node is 300 mm.
The length Lt2 of the head of the second node is 100 mm, and the length Lt2 is 100 mm.
The protruding height Lh2 of the second node is 100 mm, and the protrusion height Lh2 is 100 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ × Dp2)
Satisfy the relationship shown in
A knot pile characterized in that the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion. In a joint pile provided with a first section pile and a second section pile connected to the first section pile.
The first section pile is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body portion and the first section portion include the first concrete, and the first main body portion and the first section portion include the first concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear allowable stress of the first concrete is τ1,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the allowable short-term shear stress of the first concrete, and the short-term maximum pile circumference per pitch of at least two first nodes. Greater than surface friction bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ1 × Dp1)
Satisfy the relationship shown in
The second section pile is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body portion and the second section portion include the second concrete, and the second main body portion and the second section portion include the second concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
Let Lh2 be the height of protrusion of the second node from the second main body in the radial direction of the second main body.
When the short-term shear allowable stress of the second concrete is τ2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second section is determined by the root area of the second section and the allowable short-term shear stress of the second concrete, and the short-term maximum pile circumference per pitch of at least two second sections. Greater than surface friction bearing capacity ,
The length Lr2 at the base of the second node is 230 mm or more and 300 mm or less.
The length Lt2 of the head of the second node is 130 mm or more and 200 mm or less.
The protruding height Lh2 of the second node is 50 mm, and the protrusion height Lh2 is 50 mm.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ2 × Dp2)
Satisfy the relationship shown in
A joint pile characterized in that the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion. In a knot pile provided with a first portion and a second portion integrally connected to the first portion.
The first part is
Cylindrical first body and
Includes at least two first nodes projecting from the outer peripheral surface of the first body.
The first main body and the first section contain concrete and contain concrete.
Let Lr1 be the length of the base of the first node on the side of the first main body in the axial direction of the first main body.
Let Lt1 be the length of the head of the first node portion opposite to the first main body portion in the axial direction of the first main body portion.
The outer diameter of the first main body is set to Dp1.
Let Lh1 be the height of protrusion of the first node portion from the first main body portion in the radial direction of the first main body portion.
When the short-term shear stress tolerance of the concrete is τ,
The following formula:
Lr1-2 × (3 ^ 0.5) × Lh1 ≦ Lt1 ≦ Lr1-2 / (3 ^ 0.5) × Lh1
Satisfy the relationship shown in
The shear strength of the first node is determined by the root area of the first node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two first nodes. Greater than bearing capacity ,
The length Lr1 at the base of the first node is 230 mm or more and 300 mm or less.
The length Lt1 of the head of the first node is 130 mm or more and 200 mm or less.
The protruding height Lh1 of the first node is 50 mm, and the protrusion height Lh1 is 50 mm.
The pitch of the at least two first nodes is 1 m.
The following formula:
Lr1> 380 × (Dp1 + 2 × Lh1) / (τ × Dp1)
Satisfy the relationship shown in
The second part is
Cylindrical second body and
Including at least two second nodes protruding from the outer peripheral surface of the second main body.
The second main body and the second section include the concrete and contain the concrete.
Let Lr2 be the length of the base of the second node on the side of the second main body in the axial direction of the second main body.
Let Lt2 be the length of the head of the second node portion on the side opposite to the second main body portion in the axial direction of the second main body portion.
The outer diameter of the second main body is set to Dp2.
Lh is the protruding height of the second node from the second main body in the radial direction of the second main body.
When it is 2,
The following formula:
Lr2-2 × (3 ^ 0.5) × Lh2 ≦ Lt2 ≦ Lr2-2 / (3 ^ 0.5) × Lh2
Satisfy the relationship shown in
The shear strength of the second node is determined by the root area of the second node and the short-term shear allowable stress of the concrete, and the short-term maximum pile peripheral friction per pitch of at least two second nodes. Greater than bearing capacity ,
The length Lr2 at the base of the second node is 230 mm or more and 300 mm or less.
The length Lt2 of the head of the second node is 130 mm or more and 200 mm or less.
The protruding height Lh2 of the second node is 50 mm, and the protrusion height Lh2 is 50 mm.
The pitch of the at least two second nodes is 1 m.
The following formula:
Lr2> 380 × (Dp2 + 2 × Lh2) / (τ × Dp2)
Satisfy the relationship shown in
A knot pile characterized in that the outer diameter Dp1 of the first main body portion is larger than the outer diameter Dp2 of the second main body portion.

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