JP6466236B2 - H steel pile and its placing method, and steel pipe pile placing method - Google Patents

Description

  The present invention relates to an H steel pile, a method for placing the steel pile, and a method for placing a steel pipe pile.

  Foundation piles such as H steel piles and steel pipe piles placed on the ground support the structures built on them. The support force of the foundation pile depends on the peripheral friction force with the ground and the support force of the tip part.

  Since the normal foundation pile has the circumference and pile tip area required for the part penetrating into the support layer of the ground over the entire length, when it is necessary to demonstrate high support force only at the tip part, Waste of material etc. of the main body portion is increased. Therefore, steel pipe piles whose tip portions are expanded in diameter are known as foundation piles that increase the support force of the tip portions (see, for example, Patent Documents 1 and 2). In these steel pipe piles, not only the support force of the tip portion is increased, but also the diameter of the main body portion is smaller than the diameter of the tip portion, so the material cost and the like are reduced.

JP-A-8-85939 JP 2004-316411 A

  In the steel pipe piles disclosed in Patent Documents 1 and 2, the placing method is limited by the shape of the tip portion thereof, and it is not necessarily applicable to a plurality of construction methods.

  Accordingly, the present invention provides an H steel pile that can obtain a high supporting force while reducing material costs and the like, and can be driven by a plurality of construction methods, a method for driving the steel pile, and a method for driving a steel pipe pile. The purpose is to provide.

  The present invention comprises a main body part, a tip part provided on one end side of the main body part and wider than the main body part, and a connection part for connecting the main body part and the tip part, and in the calculation of the bearing capacity of the pile The circumference of the tip and the pile tip area provide an H steel pile that is larger than the circumference and the pile tip area corresponding to the circumference and the pile tip area in the main body.

  According to this H-steel pile, a high support force is provided by the peripheral surface friction and the tip support force by causing the tip portion, which has been widened and the circumference and the tip end area of the pile, to reach the support layer of the ground. Can be obtained. Moreover, since the main-body part of the H steel pile is the normal aspect which is not widened, material cost etc. are reduced compared with the case where the whole H steel pile is formed with the width | variety of a front-end | tip part. And this H steel pile can use a several placement method.

  It is preferable that the connecting portion is interposed between the main body portion and the tip portion in the direction in which the H steel pile is placed, and is continuously widened from the main body portion side toward the tip portion side. With this shape, it is easy to allow the H steel pile to enter the ground, which is particularly convenient when using a driving method.

  Further, the present invention is an H steel pile placing method for placing the H steel pile on a ground having a support layer and a soft layer positioned above and softer than the support layer, the soft layer And a vertical hole forming step of excavating the support layer to form a vertical hole, an erection step of inserting an H steel pile into the vertical hole to reach at least a part of the tip portion in the support layer, and an erection step There is provided a method for placing an H steel pile having a driving step of driving the H steel pile by striking later, or a rooting step of solidifying at least a part of the tip portion with a solidifying material.

  Furthermore, the present invention is an H steel pile placing method for placing the H steel pile on the ground having a support layer and a soft layer located above and softer than the support layer, A method for placing an H steel pile having an erection process that penetrates the soft layer and reaches the inside of the support layer by hitting.

  As described above, a plurality of placing methods can be used to place the H steel pile on the ground. In any of the construction methods, the widened tip portion reaches and is fixed in the support layer, so that a high bearing force can be obtained by the large circumference and the pile tip area.

  Further, the present invention is a steel pipe pile placing method for placing a steel pipe pile on the ground having a support layer and a soft layer located above and softer than the support layer, the steel pipe pile being a main body And a tip provided on one end of the main body, extending in the direction of placing the steel pipe pile and having a diameter larger than that of the main body, and a connecting portion for connecting the main body and the tip. The circumference of the tip and the pile tip area in the calculation of the bearing capacity of the body are both larger than the circumference and the pile tip area corresponding to the circumference and the pile tip area in the main body, and the steel pipe pile is softened by indenting An erection process for penetrating the layer and reaching the support layer; an erection process for driving the steel pipe pile by striking after the erection process; or a consolidation process for solidifying at least a part of the tip with a solidifying material; , A method for placing a steel pipe pile.

  Furthermore, the present invention is a steel pipe pile placing method for placing a steel pipe pile on the ground having a support layer and a soft layer located above and softer than the support layer, wherein the steel pipe pile has a main body portion. And a tip portion provided on one end side of the main body portion, extending in the direction of placing the steel pipe pile and having a diameter larger than that of the main body portion, and a connecting portion for connecting the main body portion and the tip portion, In the bearing capacity calculation, the circumference of the tip and the pile tip area are both larger than the circumference and the pile tip area corresponding to the circumference and pile tip area in the main body, and the steel pipe pile is pierced to penetrate the soft layer. Thus, a method for placing a steel pipe pile having an erection process for reaching the inside of the support layer is provided.

  The steel pipe piles in the plurality of placement methods are easy to enter into the ground and can withstand driving because the tip portion extends in the direction of placement of the steel pipe pile. And after placing, since the front-end | tip part expanded in diameter so that perimeter and a pile front-end | tip area may become large has reached | attained in the support layer of a ground, high support force can be acquired. Moreover, since the main-body part is the normal aspect which is not diameter-expanded, material cost etc. are reduced compared with the case where the whole steel pipe pile is formed with the diameter of a front-end | tip part.

  According to the present invention, it is possible to obtain a high supporting force while reducing material costs and the like, and an H steel pile that can be driven by a plurality of construction methods, a method for driving the steel pile, and a steel pipe pile. A method can be provided.

It is a figure which shows the outline | summary of the ground which drives a pile. (A) is a front view of H steel pile, (b) is a side view of H steel pile. FIG. 3A is an end view taken along the line IIIa-IIIa in FIG. 2A, and FIG. 2B is an end view taken along the line IIIb-IIIb in FIG. It is a front view of a steel pipe pile. 5A is an end view taken along the line Va-Va in FIG. 4, and FIG. 5B is an end view taken along the line Vb-Vb in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part or an equivalent part, and the overlapping description is abbreviate | omitted.

  In this embodiment, the ground on which H steel piles and steel pipe piles (both pre-made piles) are placed as foundation piles is as seen in a coastal area reclaimed by, for example, dredging as shown in FIG. The ground has a soft layer 101 that reaches a depth of several tens of meters from the ground surface, and a support layer 102 that is composed of a gravel layer, a cohesive clay, or the like that extends below the soft layer 101. Here, the soft layer 101 refers to a layer that hardly contributes to the support of the foundation pile 10. The foundation pile 10 supports the structure 20 constructed on the ground, and the supporting force is determined by the peripheral frictional force of the portion in contact with the support layer 102 and the supporting force of the tip portion.

<First Embodiment>
As 1st Embodiment, the H steel pile and its placement method are demonstrated. As shown in FIG. 2 and FIG. 3, the H steel pile 1 of the present embodiment has a main body part 11 that is long in section H shape, and is wider than the main body part 11 on one end side of the main body part 11. A provided tip portion 12 having an H-shaped cross section is provided. The widening is performed in both the vertical and horizontal directions of the H shape.

  Between the main body part 11 and the front end part 12, a connection part 13 that is continuously widened while maintaining a cross-sectional H shape from the main body part 11 side toward the front end part 12 side is interposed. The part 12 is connected. Here, the distal end portion 12 and the connecting portion 13 extend in a direction that matches the central axis of the main body portion 11, that is, the direction in which the H steel pile 1 is placed. The main body part 11, the connection part 13 and the tip part 12 all have the same thickness, and are connected and integrated together by welding.

  Regarding the length in the placing direction, the length of the main body 11 depends on the depth of the support layer, but is usually 20 m to 40 m. The length of the distal end portion 12 is preferably 2 Bm to 4 Bm (B represents the width of the H steel pile), and preferably 1 m to 2 m. The length of the connecting portion 13 is preferably 2 Bm, and more preferably about 1 m when the main body portion is H-500.

  Regarding the size relationship between the widths of the front end portion 12 and the main body portion 11, the circumference of the front end portion 12 (referred to as “L1”) and the pile front end area (referred to as “S1”) in the calculation of the bearing capacity of the pile are the main body portion. 11 is larger than the circumference (referred to as “L2”) and the pile tip area (referred to as “S2”) corresponding to the circumference of the tip 12 and the pile tip area.

  Here, “peripheral length and pile tip area in pile bearing capacity calculation” is a quadrilateral formed by connecting the four corners in a straight line in order when the tip 12 of the H steel pile 1 is viewed from the axial direction. The length and area around the area A12 (see the two-dot chain line in FIG. 3A). 3A is an end view taken along the line IIIa-IIIa in FIG. 2A and does not represent the tip of the tip portion 12, but this figure is a diagram of the tip of the tip portion 12. FIG. As a substitute.

  Moreover, "the circumference and the pile tip area corresponding to the circumference of the tip part and the pile tip area in the main body part" means that the four corners when the body part 11 of the H steel pile 1 is viewed from the axial direction are connected in a straight line in order. The length and area around the square area A11 (see the two-dot chain line in FIG. 3B) formed by

  Specifically, regarding the circumference, L1 / L2 is preferably 1.3 to 1.7. Regarding the pile tip area, S1 / S2 is preferably 1.7 to 2.9.

  As for a specific circumference, L1 is preferably 200 cm to 360 cm, and L2 is preferably 120 cm to 280 cm.

  The angle of widening of the connecting portion 13 (see θ1 in FIG. 2) is 20 from the ease of placing the H steel pile 1 on the basis of the placing direction of the H steel pile 1 (the axial direction of the main body portion 11). Degrees to 35 degrees are preferable, and 25 degrees to 30 degrees are more preferable.

  A method for placing the H steel pile 1 will be described. H steel pile 1 manufactured at the factory as a ready-made pile is transported to the installation site. In the case where the length of the main body 11 becomes an obstacle to transportation, it may be transported after being disassembled into a plurality of suitable lengths and then connected on site. As a connection method, in addition to welding, connection by an attachment plate can be employed.

  The H steel pile 1 can be driven by a pre-boring method. First, in the ground having the soft layer 101 and the support layer 102 shown in FIG. 1, the soft layer 101 and the support layer 102 are excavated to form vertical holes (vertical hole forming step). Next, the H steel pile 1 is inserted into the vertical hole, and at least a part of the distal end portion 12 reaches the support layer 102 (building process). Thereafter, the H steel pile 1 is hammered to perform the final driving (driving process), or the solidified material is injected into the vertical hole to solidify at least a part of the tip portion 12 (rooting process). The steel pile 1 is fixed.

  Moreover, the H steel pile 1 can be driven by a driving method. That is, in the ground having the soft layer 101 and the support layer 102 shown in FIG. 1, the H steel pile 1 is set up in the vertical direction, penetrates the soft layer 101 by hammering, and reaches the tip 12 into the support layer 102. (Building process)

  When the H steel pile 1 is driven by the above-described construction method, the tip 12 having a large circumference and pile tip area reaches the support layer 102 of the ground. Therefore, high support is provided by the peripheral friction and the tip support force. You can gain power. Moreover, since the main-body part 11 of the H steel pile 1 has the normal width | variety which is not widened, compared with the case where the H steel pile 1 whole is formed with the width | variety of the front-end | tip part 12, material cost and construction cost are reduced. . Furthermore, in order to obtain the same supporting force as that exhibited by the H steel pile 1 of the present embodiment using a conventional H steel pile whose tip is not widened, the portion embedded in the support layer 102 In the H steel pile 1 of this embodiment, since the length of the entire pile can be reduced by the high supporting force of the widened tip portion 12, the material cost and the construction cost are high. It is further reduced.

  Moreover, since the connection part 13 is continuously widened toward the front-end | tip part 12 side from the main-body part 11 side, it is easy to make the H steel pile 1 approach in the ground during placement. This is particularly convenient for the driving method.

<Second Embodiment>
As a second embodiment, a steel pipe pile and its placing method will be described. As shown in FIGS. 4 and 5, the steel pipe pile 2 of the present embodiment is provided with a main body 21 having a circular cross section and extending in a long shape, and a diameter larger than that of the main body 21 on one end side of the main body 21. The tip portion 22 having a circular cross section is provided.

  Between the main body portion 21 and the distal end portion 22, there is a connecting portion 23 that is continuously expanded in diameter while maintaining a circular cross section from the main body portion 21 side toward the distal end portion 22 side. The part 22 is connected. Here, the front-end | tip part 22 and the connection part 23 are extended in the direction corresponding to the center axis | shaft of the main-body part 21, ie, the placement direction of the steel pipe pile 2. As shown in FIG. The main body part 21, the connection part 23, and the tip part 22 have the same thickness, and are connected and integrated together by welding.

  About the preferable dimension of the main-body part 21, the front-end | tip part 22, and the connection part 23, it is the same as that of the case of the H steel pile 1. FIG.

  Regarding the size relationship between the diameters of the tip portion 22 and the main body portion 21, the circumference of the tip portion 22 (referred to as “L3”) and the pile tip area (referred to as “S3”) in the pile bearing capacity calculation are the main body portion. 21, both the circumference of the tip 22 and the circumference corresponding to the pile tip area (referred to as “L4”) and the pile tip area (referred to as “S4”) are both greater.

  Here, “peripheral length and pile tip area in pile bearing capacity calculation” means the maximum circle when the tip 22 of the steel pipe pile 2 is viewed from the axial direction (that is, the circle formed by the outer circumferential surface of the steel pipe). ) Inside the region A22 (refer to the two-dot chain line in FIG. 5A). 5A is an end view taken along the line Va-Va in FIG. 4 and does not represent the tip of the tip portion 22, but this drawing is used as a diagram of the tip of the tip portion 22. ing.

  Moreover, "the circumference and the pile tip area corresponding to the circumference of the tip and the pile tip area in the main body part" means the region A21 inside the maximum circle when the main body 21 of the steel pipe pile 2 is viewed from the axial direction. (Refer to the two-dot chain line in FIG. 5B).

  Specifically, for the circumference, L3 / L4 is preferably 1.25 to 1.4. Regarding the pile tip area, S3 / S4 is preferably 1.6 to 2.0.

  As for a specific circumference, L3 is preferably 220 cm to 340 cm, and L4 is preferably 160 cm to 250 cm.

  The angle of expansion of the connecting portion 23 (see θ2 in FIG. 4) is 20 degrees with reference to the direction of placing the steel pipe pile 2 (the axial direction of the main body portion 21) from the ease of placing the steel pipe pile 2. -35 degrees are preferable, and 25 degrees to 30 degrees are more preferable.

  A method for placing the steel pipe pile 2 will be described. The steel pipe pile 2 manufactured at the factory as a ready-made pile is transported to the installation site. If the length of the main body 21 becomes an obstacle to transportation, it may be transported after being disassembled into a plurality of appropriate lengths, and then connected on site. As a connection method, welding can be employed.

  The steel pipe pile 2 can be driven by a medium excavation method. First, in the ground having the soft layer 101 and the support layer 102 shown in FIG. 1, the steel pipe pile 2 is press-fitted into the ground while being dug by an auger, and the tip portion 22 is penetrated through the soft layer 101 to the support layer. 102 is reached (building process). Then, the steel pipe pile 2 is fixed by hammering the steel pipe pile 2 to perform final driving (driving process) or by solidifying at least a part of the tip portion 22 with a solidifying material (root hardening process).

  Moreover, the steel pipe pile 2 can be driven by a driving method. That is, in the ground having the soft layer 101 and the support layer 102 shown in FIG. 1, the steel pipe pile 2 is set up in the vertical direction and penetrated through the soft layer 101 by hammering so that the tip 22 reaches the support layer 102. (Building process).

  When the steel pipe pile 2 is driven by the above-described construction method, the tip 22 having a large circumferential length and pile tip area reaches the support layer 102 of the ground. Can be obtained. Moreover, since the main-body part 21 of the steel pipe pile 2 has normal thickness which is not diameter-expanded, compared with the case where the steel pipe pile 2 whole is formed with the thickness of the front-end | tip part 22, material cost and construction cost are reduced. Yes. Furthermore, in order to obtain a supporting force equivalent to that exhibited by the steel pipe pile 2 of the present embodiment using a conventional steel pipe pile whose tip is not expanded, the length of the portion embedded in the support layer 102 is long. In the steel pipe pile 2 of the present embodiment, since the length of the entire pile can be reduced by the high supporting force of the expanded tip portion 22, the material cost and the construction cost are further increased. Reduced.

  Moreover, since the connection part 23 is continuously diameter-expanded toward the front-end | tip part 22 side from the main-body part 21 side, it is easy to make the steel pipe pile 2 approach in the ground during placement. This is particularly convenient for the driving method.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the connection portion is continuously widened or expanded in diameter while maintaining the cross-sectional shape from the main body portion side toward the distal end portion side. The shape does not need to be the same as that of the tip portion. For example, the main body portion and the tip portion may be connected by extending in the width direction of the pile. That is, in the case of the H steel pile, a flat plate wider than the main body portion may be connected so as to cover the front end surface of the main body portion, and the front end portion may be connected to the opposite surface of the flat plate. In the case of a steel pipe pile, the diameter of the main body portion may be folded at a right angle in the radial direction to expand the diameter, and after the diameter expansion, the tip portion may be folded at a right angle in the placing direction.

  Moreover, in the said embodiment, although the thickness of all the members showed the same aspect, you may make the thickness of a front-end | tip part thicker than the thickness of a main-body part.

  DESCRIPTION OF SYMBOLS 1 ... H steel pile, 2 ... Steel pipe pile, 11, 21 ... Main-body part, 12, 22 ... Tip part, 13, 23 ... Connection part, 101 ... Soft layer, 102 ... Support layer.

Claims (4)

The main body,
Provided on one end side of the main body part, and a tip part wider than the main body part,
A connecting portion for connecting the main body and the tip, and an H steel pile comprising:
The widening is such that the H-shaped shape in the H-shaped cross section of the H steel pile is expanded in both vertical and horizontal directions,
The H steel pile in which the circumference of the tip and the pile tip area in the pile bearing capacity calculation are both larger than the circumference and the pile tip area corresponding to the circumference and the pile tip area in the main body.   The connecting portion is interposed between the main body portion and the tip end portion in the direction of placing the H steel pile, and is continuously widened from the main body portion side toward the tip end side. The H steel pile according to claim 1. An H steel pile placing method for placing the H steel pile according to claim 1 or 2 on a ground having a support layer and a soft layer located above and softer than the support layer,
A vertical hole forming step of excavating the soft layer and the support layer to form a vertical hole;
An erection step of inserting the H steel pile into the vertical hole and reaching at least a part of the tip in the support layer;
An H steel pile driving method comprising a driving step of driving the H steel pile by hitting after the erection step, or a rooting step of rooting at least a part of the tip portion with a solidifying material. An H steel pile placing method for placing the H steel pile according to claim 1 or 2 on a ground having a support layer and a soft layer located above and softer than the support layer,
A method for placing an H steel pile, comprising the step of piercing the H steel pile by penetrating the soft layer and reaching the support layer.

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