JP6335564B2 - Foundation structure of abutment, retaining wall or structure - Google Patents

Description

The present invention relates to an abutment on which a front surface faces water and earth pressure from the back side acts, or a retaining wall foundation structure for preventing collapse of a slope due to earth pressure acting from the back side, and the back surface soil pressure from the side is about the basic structure of the structure to act.

  Structures such as piers and abutments are often constructed with soft ground such as rivers and seas, so steel pipe piles are built up to a good quality ground below the soft ground. The lower part of the structure is joined to the head of the steel pipe pile.

However, since the abutment supports the upper structure and plays a role of retaining the back surface, a load such as earth pressure from the back side acts in addition to the load from the upper structure.
In particular, horizontal force and bending moment due to earth pressure on the back side are generated at the pile head of the steel pipe, and the structure is greatly displaced or inclined in the front direction, which may cause various adverse effects. In addition, as a structure on which earth pressure from the back side acts, a retaining wall for preventing the slope from collapsing has the same problem.

  In Patent Document 1, for the seismic reinforcement of an existing abutment, an end of a tubular reinforcing member is installed on the ground on the back side, and the other end is installed on the abutment. The structure is disclosed.

Japanese Patent Publication No. 2011-168975

  However, the above-described seismic reinforcement method or the like has to provide a reinforcing member up to the ground on the back side. In addition, the existing abutments were only provided with seismic reinforcement.

New abutment it soil pressure acting from the back side of such abutment, retaining wall, or a valid foundation structure in the construction of structure creation, has been required to.

An object of the present invention is to provide a base structure capable of sufficiently resistive abutment soil pressure from the rear side you action, retaining walls or according earth pressure on the substructure of structure creation.

According to the present invention, a first characteristic feature of the basic structure of the abutment or retaining wall, front you soil pressure acting from the back side facing the water abutment or due to receiving earth pressure acting from the back side a foundation structure retaining wall for preventing collapse of the slope, comprising a plurality of steel pipe pile rows, with at least arranged front row steel pipe column to the front is the front side of the abutment or the retaining wall, than steel Kankuiretsu in the back side of the abutment or the retaining wall, in that the stiffness is configured high.

The abutment or retaining wall the soil pressure is that to act from the back side, the pile head of the steel pipe, the horizontal force and bending moment due to the back side of the earth pressure is generated. Therefore, a load is applied from the back side of the abutment or the retaining wall to the front side. By constructing at least the foremost steel pipe pile row arranged in the foreground to be more rigid than the other steel pipe pile rows, the front row steel pile column can support downward load, and the other Since the load in the upward direction can be supported, a large displacement or inclination in the front direction due to the load applied to the abutment or the retaining wall can be prevented. That is, it is possible to reduce the displacement and inclination of the abutment or retaining wall that the arising by the horizontal forces and bending moments.
For example, if the materials constituting the steel pipe pile are the same, the rigidity can be increased by increasing the plate thickness or increasing the diameter.

  The second characteristic configuration is that at least the steel pipe pile constituting the front row steel pipe pile row is thicker than the steel pipe pile constituting the other steel pipe pile row, and at least the steel pipe constituting the front row steel pipe pile row By increasing the thickness of the pile, the rigidity on the front side of the foundation structure can be increased.

  The third characteristic configuration is that at least the steel pipe pile constituting the front row steel pipe pile row is larger in diameter than the steel pipe pile constituting the other steel pipe pile row, and at least the steel pipe constituting the front row steel pipe pile row By increasing the diameter of the pile, the rigidity of the front side of the foundation structure can be increased.

  The fourth characteristic configuration is that at least the steel pipe pile constituting the front row steel pipe pile row is formed of a material having higher strength than the steel pipe pile constituting the other steel pipe pile row, and at least the front row steel pipe pile. The rigidity of the front side of the foundation structure can be increased by increasing the strength of the steel pipe piles constituting the pile row.

  The fifth characteristic configuration is that at least the steel pipe piles constituting the front row steel pipe pile row have a larger number than the steel pipe piles constituting the other steel pipe pile row, and at least the steel pipe constituting the front row steel pipe pile row By increasing the number of piles, the rigidity on the front side of the foundation structure can be increased.

The sixth characteristic configuration is that the steel pipe pile constituting the front row steel pipe pile row is a diagonal pile, and at least the steel pipe pile constituting the front row steel pipe pile row is a diagonal pile. Stiffness can be increased. Since the slant pile has a greater horizontal load bearing capacity than the steel pipe pile arranged vertically, the displacement and inclination of the abutment or retaining wall are efficiently suppressed. The effect is large when the proportion of the diagonal piles in all the piles is large.

According to the present invention, characteristic feature of the substructure of the structure is a substructure of a structure soil pressure from the rear side is applied, includes a plurality of steel pipe pile rows, the steel pipe pile string before Symbol plurality of rows Among them, all of the steel pipe pile rows located on the foremost side from the center of gravity of the structure are configured to have higher rigidity than the other steel pipe pile rows .

In structures where earth pressure from the back side acts, horizontal force and bending moment due to earth pressure on the back side are generated at the pile head of the steel pipe. At that time, a bending moment is generated around the center of gravity of the structure.

By configuring the steel pipe pile row at the forefront side of the center of gravity to be higher than the rigidity of other steel pipe pile rows, the displacement and inclination of the structure caused by horizontal force and bending moment can be effectively reduced. Can be reduced. For example, if the material constituting the steel pipe pile is the same, the rigidity can be increased by increasing the plate thickness or increasing the diameter.

  ADVANTAGE OF THE INVENTION According to this invention, the foundation structure which can fully resist the earth pressure concerning the structure where the earth pressure from the back side acts can be provided.

It is explanatory drawing of the abutment provided with the foundation structure by 1st embodiment of this invention. It is explanatory drawing of the arrangement | sequence of a steel pipe pile. It is explanatory drawing of the analysis item performed about the foundation structure. It is explanatory drawing of the analysis result performed about the foundation structure. It is explanatory drawing of the abutment provided with the foundation structure by 2nd embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

FIG. 1 shows an abutment 3 of a bridge over a river or the sea as a structure on which earth pressure from the back side acts.
The abutment 3 is constructed at the edge of the bridge and connects the attachment road and the bridge, and supports the load from the upper structure such as a bridge girder and the earth pressure load of the embankment 2 on the back side. The front of the abutment 3 faces the river 1 or the sea water 1. The abutment 3 is not limited to a bridge over a river or the sea, but is also applied to an overpass or overpass.

  Since the abutment 3 is often constructed with soft ground, in this embodiment, steel pipe piles (front row steel pipe pile row 10 and rear row steel pipe pile row 20) are cast to the good quality ground below the soft ground. The lower part of the abutment 3 is coupled to the head of the steel pipe pile (the front row steel pipe pile row 10 and the rear row steel pipe pile row 20). Accordingly, the steel pipe piles (the front row steel pipe pile row 10 and the rear row steel pipe pile row 20) are the foundation structure of the abutment 3.

  The steel pipe piles (front row steel pipe pile row 10 and rear row steel pipe pile row 20) are, for example, several tens of ones manufactured at a factory so as to reach a support layer that is a hard ground below the soft ground. When laying down to a depth of meters, it is built in the ground while sequentially connecting on site. Steel pipe piles (front row steel pipe pile row 10 and rear row steel pipe pile row 20) are an impact method installed in the ground by striking with a hydraulic hammer or the like, a vibration method installed in the ground while applying vibration by a vibro hammer, a pile body It is constructed by the Nakabori method, which is installed in the ground while excavating the hollow part of the steel, the rotary press-in method in which the blade is attached to the tip part and pressed into the ground while rotating, and the other steel pipe soil cement pile method.

  The arrangement of steel pipe piles (front row steel pipe pile row 10 and rear row steel pipe pile row 20) takes into account the shape and dimensions of the abutment 3 on the foundation, the size and number of steel pipe piles, the influence of group piles, construction conditions, etc. It is determined to receive the load evenly with respect to the sustained load. In this embodiment, as shown in FIG. 2, the front row steel pipe pile row 10 is composed of four steel pipe piles 11, 12, 13, and 14, and the rear row steel pipe pile row 20 is composed of four steel pipe piles 21, 22, 23. , 24. Each steel pipe pile 11-14, 21-24 is arrange | positioned at equal intervals, respectively by planar view.

  The steel pipe piles 11-14 which comprise the front row steel pipe pile row | line | column 10 are comprised with the SKK400 material of diameter 800mm and plate | board thickness 16mm. On the other hand, the steel pipe piles 21-24 which comprise the back row steel pipe pile row | line | column 20 are comprised with the SKK400 material of diameter 800mm and plate | board thickness 9mm. Even if they have the same diameter, if the plate thickness is increased, the bending rigidity of the steel pipe pile increases, so that a foundation structure having higher rigidity in the front row steel pipe pile row 10 than in the rear row steel pipe pile row 20 can be realized.

Based on FIG.3 and FIG.4, the analysis result performed about the foundation structure by this embodiment is demonstrated.
Here, δv2 is the axial displacement of the front row steel pipe pile row, δv1 is the axial displacement of the rear row steel tube pile row, V is the vertical load (acting force), H is the horizontal load (acting force), and M is the moment load ( Acting force), θ represents a rotation angle, δh represents a displacement in the front-rear direction, and δv2-δv1 represents a displacement in the vertical direction.
In the embodiment, the front row steel pipe pile row 10 is constituted by a steel pipe pile having a diameter of 800 mm and a plate thickness of 16 mm, and the rear row steel pipe pile row 20 is constituted by a steel pipe pile having a diameter of 800 mm and a plate thickness of 9 mm.

  As Comparative Example 1, the front row steel pipe pile row 10 was made of a steel pipe pile having a diameter of 800 mm and a plate thickness of 9 mm, and the rear row pipe tube pile row 20 was made of a steel pipe pile having a diameter of 800 mm and a plate thickness of 9 mm. As shown in FIG. 4, the example is more stable than the comparative example 1 over all items of the axial displacement δv2, the axial displacement δv1, the rotation angle θ, the longitudinal displacement δh, and the vertical displacement δv2-δv1. Recognize.

  As comparative example 2, as the comparative example 2, the front row steel pipe pile row 10 is constituted by a steel pipe pile having a diameter of 800 mm and a plate thickness of 9 mm, and the rear row steel pipe pile row 20 is constituted by a steel pipe pile having a diameter of 800 mm and a plate thickness of 16 mm. did. As shown in FIG. 4, as a conclusion, the example is more stable than the comparative example 2 over all items of the axial displacement δv2, the axial displacement δv1, the rotation angle θ, the longitudinal displacement δh, and the vertical displacement δv2-δv1. I understand that.

  In the second embodiment, the values of the axial displacement δv2 and the axial displacement δv1 are smaller than those in the first embodiment, but the rotation angle θ, the longitudinal displacement δh, and the vertical displacement δv2-δv1 are larger than those in the first embodiment. End up. Therefore, it turns out that it is not preferable to make the rigidity of the front row steel pipe pile row 10 smaller than the rear row steel pipe pile row 20.

  As described above, by configuring the front row steel pipe pile row 10 to be more rigid than the rear row steel pipe pile row 20, the displacement and inclination of the structure of the abutment 3 caused by the bending moment can be reduced.

  Although embodiment mentioned above demonstrated the case where the thickness of the steel pipe piles 11-14 which comprise the front row steel pipe pile row | line | column 10 was thicker than the thickness of the steel pipe piles 21-24 which comprise the back row steel pipe pile row | line | column 20, it is not restricted to this. Absent. Even if it is the same thickness, if the diameter is increased, the bending rigidity of the steel pipe pile increases, and the rigidity on the front side of the foundation structure can be increased. Moreover, even if it is the same shape, by using a material having a higher tensile strength, yield point or proof stress than SKK400, for example, using SKK490, or filling concrete in the steel pipe of SKK400, as a result, The bending rigidity increases and the rigidity of the front side of the foundation structure can be increased. Furthermore, even if the same steel pipe pile is used, by increasing the number of steel pipe piles constituting the front row steel pipe pile row 10 as compared with the steel pipe piles constituting the rear row steel pipe pile row 20, the rigidity on the front side of the foundation structure is increased. Can do.

  Moreover, as shown in FIG. 5, you may make the steel pipe pile which comprises the front row steel pipe pile row | line 10 into a diagonal pile. By making the steel pipe piles 11 to 14 constituting at least the front row steel pipe pile row 10 into diagonal piles, the rigidity on the front side of the foundation structure can be increased. Since the diagonal pile has a greater horizontal load bearing capacity than the steel pipe pile arranged vertically, the displacement and inclination of the structure are efficiently suppressed. The effect is large when the proportion of the diagonal piles in all the piles is large.

In addition, although embodiment mentioned above demonstrated the case where the foundation of the abutment 3 was comprised with the steel pipe pile of front and rear row steel pipe pile row | line | column 10 and the back row steel pipe pile row | line | column 20, the arrangement | sequence of a steel pipe pile is not restricted to this.
For example, three or more steel pipe piles may be provided before and after. Even in such a case, it is possible to effectively counter the bending moment by configuring the steel pipe pile row in at least the front row so as to have higher rigidity than the other steel pipe pile rows.
Since a bending moment is generated around the center of gravity of the abutment 3, by configuring all of the steel pipe pile rows on the forefront side from this center of gravity position to be more rigid than the other steel pipe pile rows, It can contribute to the stability of the structure effectively.

  In the above-described embodiment, the abutment has been described as an example of the structure on which earth pressure from the back side acts. However, the structure may be a retaining wall for preventing the slope from collapsing. By providing the above-mentioned foundation structure, the retaining wall is restrained from large displacement and inclination in the front direction.

  Each of the above-described embodiments is an example of the present invention, and the present invention is not limited by the description. The specific configuration of each part can be appropriately changed and designed within the range where the effects of the present invention are exhibited. is there.

10 Front row steel pipe pile row (foundation structure)
11 Steel pipe piles 12 Steel pipe piles 13 Steel pipe piles 14 Steel pipe piles 20 Back row steel pipe pile rows (foundation structure)
21 Steel pipe piles 22 Steel pipe piles 23 Steel pipe piles 24 Steel pipe piles 30 Diagonal piles

Claims (7)

Front you soil pressure acting from the back side facing the water abutment, or to a foundation structure of retaining wall for preventing collapse of the slope due to receive earth pressure acting from the back side,
With multiple steel pipe pile rows,
Together with at least placed front row steel pipe column to the front is the front side of the abutment or the retaining wall, than steel Kankuiretsu on the back side of the abutment or the retaining wall, the rigidity is configured high Basic structure characterized by   2. The foundation structure according to claim 1, wherein at least a steel pipe pile constituting the front steel pipe pile row is thicker than a steel pipe pile constituting the other steel pipe pile row.   The foundation structure according to claim 1 or 2, wherein a steel pipe pile constituting at least the front row steel pipe pile row has a larger diameter than a steel pipe pile constituting the other steel pipe pile row.   The steel pipe pile which comprises the said front row steel pipe pile row | line | column at least is formed with the material whose intensity | strength is higher than the steel pipe pile piece which comprises the said other steel pipe pile row | line | column. The basic structure described in 1.   The steel pipe pile which comprises the said front row steel pipe pile row | line at least has the number of steel pipe piles which comprise the said other steel pipe pile row | line, The foundation structure as described in any one of Claim 1 to 4 characterized by the above-mentioned.   The steel pipe pile which comprises the said front row steel pipe pile row | line | column is a diagonal pile, The foundation structure as described in any one of Claim 1 to 5 characterized by the above-mentioned. The basic structure of the structure where earth pressure from the back side acts,
With multiple steel pipe pile rows,
Of steel pipe piles string before Symbol plurality of rows, all of the steel pipe pile column in the center of gravity of the structure in the foreground side, from the other steel pipe pile column, characterized in that the rigidity is configured high foundation structure that.

Images