JP6287359B2 - Embankment reinforcement structure - Google Patents

Description

  The present invention relates to an embankment reinforcement structure that reinforces an embankment against an external force that tends to collapse the embankment mainly during an earthquake.

  Conventionally, as a reinforcement for embankments (bank bodies) of embankments such as rivers, the slope of the embankment is covered with a material with low water permeability or imperviousness, or the bottom edge on the bottom of the slope of the embankment In addition, it was known to construct a steel sheet pile wall in the ground along the extending direction (continuous direction) of the embankment.

  However, the slope covering does not reinforce the strength of the embankment itself, and cannot prevent the embankment from being destroyed when a large external force acts on the embankment during an earthquake or flood. In order to stabilize the embankment foundation ground against an earthquake, it is effective to place a steel sheet pile wall at the butt as described above. The steel sheet pile wall cannot prevent the embankment from collapsing.

  Therefore, for example, Patent Document 1 proposes a bank reinforcement structure in which at least one row of sheet pile walls is constructed along the length of the bank inside the bank other than the butt. More specifically, a structure in which a single sheet pile wall is constructed within the top edge of the embankment or near the shoulder on one side, or two connected to each other by a connecting material (tie rod) located near both shoulders. A structure for constructing a steel sheet pile wall in a row is described.

  By constructing steel sheet pile walls in two rows from the shoulder of the embankment to the top edge in this way, double steel sheet pile cut-off parts are constructed in the embankment, forming a structurally solid core and reinforcing the embankment can do. This makes it possible to cope with various external force conditions during floods and earthquakes. For example, it becomes possible to deal with infiltration, washing, overtopping during floods, and inertial forces and liquefaction of foundation ground during earthquakes. In the event of a flood or earthquake, the top height of the embankment can be maintained by two rows of steel sheet pile walls, preventing river flooding and preventing the bank from collapsing due to river flooding. .

JP 2003-13451 A

By the way, in order to compare the conventional embankment reinforcement structure having two rows of steel sheet pile walls and the non-measured structure without the steel sheet pile walls, the present inventors have produced models of these structures and added them. A shaking experiment was conducted.
As a result, in the conventional embankment reinforcement structure with two rows of steel sheet pile walls, the amount of settlement on the upper surface of the embankment can be reduced by about half compared to the countermeasureless measures without the steel sheet pile walls, but it is still unsatisfactory. did.
Therefore, by providing partition walls connecting the two rows of steel sheet pile walls at predetermined intervals in the continuous direction of the embankment between the two rows of steel sheet pile walls, the steel sheet pile walls are reinforced, and the deformation of the steel sheet pile during an earthquake is suppressed. Therefore, we thought that the amount of settlement on the upper surface of the embankment could be suppressed, and produced a model of this structure and conducted an excitation experiment.
As a result, it was found that the amount of settlement on the upper surface of the embankment can be sufficiently suppressed as compared with the reinforcing structure having the two rows of steel sheet pile walls.
However, when such an embankment reinforcement structure is actually constructed, it is necessary to use a large number of partition walls, so that there is a problem that the construction takes time and costs are increased.
In addition, as a result of the excitation experiment, a phenomenon was observed in which the slope (slope) of the embankment that became the model largely sinks along the steel sheet pile wall.

  This invention is made | formed in view of the said situation, and it aims at providing the embankment reinforcement structure which can reinforce effectively the steel sheet pile which comprises a steel sheet pile wall at low cost.

In order to achieve the above object, the embankment reinforcing structure of the present invention is a continuous embankment provided on an embankment foundation ground composed of a liquefied layer and a support layer below the liquefied layer, and a lower end of the embankment foundation ground. A steel sheet pile wall made of a steel sheet pile that is in the liquefied layer, reaches the upper surface of the support layer, or reaches the support layer, is provided along the continuous direction of the embankment. In the reinforcement structure,
In the steel sheet pile, a sheet pile reinforcing member is provided in a range including a boundary surface position between the embankment and the embankment foundation ground,
The steel sheet pile includes a web portion, a pair of flange portions formed continuously on both sides of the web portion, and a joint portion formed on the tip side of the pair of flange portions,
The sheet pile reinforcing member is a closing member that is joined across the ends of a pair of flange portions of the steel sheet pile and closes an open cross section of the steel sheet pile .

  In such a range, the sheet pile reinforcing member was provided based on the results of the experiment. The part where the distortion of the steel sheet pile increases during an earthquake, etc. This is because it has been found that it is near the boundary surface with the ground or below that including the boundary surface.

In the present invention, the portion where the steel sheet pile is greatly deformed at the time of an earthquake is near the boundary surface between the embankment and the embankment foundation ground, or below that including the boundary surface. By reinforcing the sheet pile with the sheet pile reinforcing member, the steel sheet pile can be effectively reinforced at low cost.
Therefore, the settlement of the whole embankment can be suppressed at a low cost as compared with a reinforcing structure having a conventional partition wall.
In addition, the steel sheet pile can be efficiently reinforced while suppressing the degree of processing, and the cost increase associated with the installation of the sheet pile reinforcing member can be suppressed.

In the configuration of the present invention, the sheet pile reinforcing member is disposed in the range of at least 2/5 of the embankment height from the vicinity of the boundary surface position between the embankment and the embankment foundation ground to the embankment foundation ground side. Is preferred.
Thus, the range of the arrangement of the sheet pile reinforcing member is limited, when the lower end of the steel sheet pile reaches the support layer constituting the lower layer in the embankment foundation ground, the part where the steel sheet pile greatly deforms during an earthquake, It is because it exists in the 2/5 range of embankment height from the boundary surface position vicinity of embankment and embankment foundation ground to the embankment foundation ground side.

  According to such a configuration, deformation of the steel sheet pile can be efficiently suppressed, and settlement of the embankment can be suppressed.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the said closing member is a substantially U-shaped cross section symmetrical to the web part and flange part of the said steel sheet pile.

  The closing member may be manufactured by processing a steel plate by welding, but it is preferable to use a member having the same cross section as the steel sheet pile and to join the member symmetrically with the steel sheet pile.

  According to such a configuration, the closing member has a substantially U-shaped cross section symmetrical to the steel sheet pile, and the closing cross section formed by the closing member and the steel sheet pile is closed when the steel sheet pile is placed. In addition, the settlement of the embankment at the time of the earthquake can be supported by this closed portion, and as a result, the settlement of the embankment can be suppressed.

  Moreover, in the said structure of this invention, the said steel sheet pile wall is provided in the said embankment by installing the said steel sheet pile in the vicinity of the both shoulders, respectively, and the said closing member is provided on the slope side of the said embankment May be directed to.

  According to such a configuration, when the steel sheet pile is placed, the earth and sand closes in the closed section by the closing member and the steel sheet pile, and the slope (slope) of the embankment tends to sink due to the subsequent earthquake. Thus, the subsidence can be supported by the closed portion in the closed section, and the subsidence can be suppressed.

Moreover, in the said structure of invention, the said steel sheet pile wall is provided in the said embankment by installing the said steel sheet pile in the vicinity of the both shoulders, respectively.
The closing member may be directed between two rows of the steel sheet pile walls.

  According to such a configuration, when the steel sheet pile is placed, the earth and sand are blocked in the closed section by the closing member and the steel sheet pile, and the movement of the earth and sand between the two rows of steel sheet pile walls is restricted. In addition to supporting the subsidence in the closed section in the closed section against the fact that the entire embankment is going to subside in the subsequent earthquake, by restraining the movement of the sand between the two rows of steel sheet pile walls of the embankment, The subsidence can be suppressed.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the processus | protrusion is formed in the surface of the side facing the said steel sheet pile in the said closure member.

  According to such a configuration, the projection between the surface of the closing member on the side of the steel sheet pile increases the friction between the clod that has entered the closed section and the closing member, and the closing effect of the closing portion can be enhanced.

Further, in the configuration of the present invention, the embankment foundation ground is composed of a liquefied layer and a support layer below it,
The lower end of the steel sheet pile is in the liquefied layer, reaches the upper surface of the support layer, or reaches the support layer.

According to such a configuration, the following effects can be obtained.
When the lower end of the steel sheet pile is in the liquefied layer, the lower end of the steel sheet pile is not fixed, so deformation that occurs in the steel sheet pile during an earthquake can be suppressed, the cross section of the steel sheet pile can be reduced, and the length of the steel sheet pile can also be shortened. The most advantageous in terms of cost.
Moreover, when the lower end of the steel sheet pile reaches the upper surface of the support layer, the lower end of the steel sheet pile is in contact with the upper surface of the support layer, so that the settlement of the steel sheet pile can be suppressed.
Further, when the lower end of the steel sheet pile reaches the support layer, the lower end of the steel sheet pile is reliably driven on the hard ground as the support layer, so that the settlement of the steel sheet pile can be reliably suppressed.

According to the present invention, the portion where the steel sheet pile is greatly deformed at the time of an earthquake is near the boundary surface between the embankment and the embankment foundation ground, or below that including the boundary surface. By reinforcing the sheet pile with a sheet pile reinforcing member, the steel sheet pile can be effectively reinforced at low cost.
Therefore, the settlement of the whole embankment can be suppressed at a low cost as compared with a reinforcing structure having a conventional partition wall.

It is sectional drawing which shows 1st Embodiment of the embankment reinforcement structure which concerns on this invention. It is sectional drawing which shows 2nd Embodiment of the embankment reinforcement structure which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the embankment reinforcement structure which concerns on this invention. It is sectional drawing which shows 4th Embodiment of the embankment reinforcement structure which concerns on this invention. It is sectional drawing which shows 5th Embodiment of the embankment reinforcement structure which concerns on this invention. It is sectional drawing which shows 6th Embodiment of the embankment reinforcement structure which concerns on this invention. An example of the steel sheet pile used for the embankment reinforcement structure which concerns on this invention is shown, (a) is sectional drawing of a steel sheet pile, (b) is sectional drawing which shows the state which joined the closure member to the steel sheet pile. The other example of the steel sheet pile used for the embankment reinforcement structure which concerns on this invention is shown, (a) is sectional drawing of a steel sheet pile, (b) is sectional drawing which shows the state which joined the closure member to the steel sheet pile. . It is a front view which shows the further another example of the steel sheet pile used for the embankment reinforcement structure which concerns on this invention. The closing member used for the embankment reinforcement structure which concerns on this invention is shown, (a) is a front view which shows an example of a closing member, (b) is a front view which shows the other example of a closing member. It is a figure for demonstrating the site | part where a steel sheet pile deform | transforms after a vibration experiment in the model of a banking reinforcement structure. In the model of the embankment reinforcement structure, it shows the slope settlement condition of the embankment after the vibration test, (a) a sectional view of the embankment reinforcement structure according to the present invention, (b) is a sectional view of a conventional embankment reinforcement structure is there.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the embankment reinforcement structure of 1st Embodiment is for reinforcing the embankment 1 used as the embankment of the sea, the river 5, etc. As shown in FIG.
The embankment 1 is a top end 1a having a horizontal upper surface at the highest part in the center. Inclined slopes 1b are formed on the left and right of the top end 1a, respectively. The upper end side of the slope 1b is a shoulder 1c, and the lower end is a slope 1d.
A river 5 extends along the embankment on the left side of the embankment 1 as the embankment. The river side of the embankment 1 is the outside of the embankment, and the opposite side of the river is the inside of the embankment.

In this embankment reinforcement structure, the steel sheet pile wall 4 which consists of the steel sheet pile 3 which reaches the embankment foundation ground 2 on the continuous embankment 1 provided on the embankment foundation ground 2 is a continuous direction of the embankment 1 (in FIG. (Perpendicular direction).
The steel sheet pile 3 is placed so as to penetrate the embankment 1 up and down from the vicinity of both shoulders 1c and 1c of the top end 1a of the embankment 1 and reaches the support layer 2a constituting the embankment foundation ground 2 to be supported. It is embedded in the layer 2a. As a result, steel sheet pile walls 4, 4 facing each other and extending along the continuous direction of the embankment 1 are constructed in the embankment 1.
The embankment foundation ground 2 is composed of a liquefied layer 2b and a support layer 2a below it. The embankment 1 is constructed on the liquefied layer 2b, and the steel sheet pile 3 penetrates the liquefied layer 2b. In the support layer 2a.

The heads (upper end portions) of the steel sheet pile walls 4, 4 are located at a height that is near the height of the top end 1 a of the embankment 1. And in the embankment 1, the structure frame | skeleton part 7 which consists of the embankment ground cut off by the steel sheet pile wall 4 and 4 provided in 2 rows is formed.
The steel sheet pile walls 4, 4 not only block the seepage flow, which is the flow of water that has permeated from the river, but also prevent the seepage failure from occurring in the embankment 1. By forming the steel sheet pile walls 4 and 4 up to the approximate top end 1a of the embankment 1, the upper part of the embankment 1 is prevented from collapsing, and an external force is applied by an earthquake or a flood. Even if this works, the river is prevented from breaking down.

  Note that the two rows of steel sheet pile walls 4, 4 may be provided with connecting members 8 such as tie rods provided at predetermined intervals along the continuous direction of the embankment 1. The connecting member 8 is bridged between the two rows of steel sheet pile walls 4 and 4 to connect them. This prevents the upper portions of the two rows of steel sheet pile walls 4 and 4 from being deformed in different directions when a large external force is applied due to a flood or an earthquake. The connecting member 8 may not be provided.

  The steel sheet pile 3 is provided with a sheet pile reinforcing member 10 in a range including a boundary surface position between the embankment 1 and the embankment foundation ground 2. Specifically, the sheet pile reinforcing member 10 is disposed in the range of at least 2/5 of the height of the embankment from the vicinity of the boundary surface position between the embankment 1 and the embankment foundation ground 2 to the embankment foundation ground 2 side.

As shown in FIGS. 7 and 8, the steel sheet pile 3 is manufactured by hot rolling, and a web portion 31 located at the center of the cross section and a pair of flange portions 32 formed continuously at both ends of the web portion 31. , 32 and joint portions 33, 33 formed on the distal end sides of the pair of flange portions 32, 32.
And the steel sheet pile 3 (3A) shown in FIG. 7 is what is called a U-shaped steel sheet pile, and had the substantially U-shaped cross-sectional shape in which the front-end | tips of a pair of flange parts 32 and 32 were provided substantially parallel. Is. On the other hand, the steel sheet pile 3 (3B) shown in FIG. 8 is a so-called hat-shaped steel sheet pile, and the ends of the pair of flange portions 32, 32 are opened in a H-shape, and the joint portions 33, 33 are formed laterally. It has a hat-shaped cross-sectional shape provided to extend.

The sheet pile reinforcing member 10 is closed between the distal ends of the pair of flange portions 32 and 32 in the middle portion in the longitudinal direction of the steel sheet pile 3 and is joined so as to close the open section of the steel sheet pile 3 to form a closed section. This is the member 10.
And the closing member 10 (10A) shown in FIG. 7 is formed by cutting the steel sheet pile 3A, which is a U-shaped steel sheet pile, into a predetermined length.
On the other hand, the closing member 10 (10B) shown in FIG. 8 cuts the steel sheet pile 3B, which is a hat-shaped steel sheet pile, into a predetermined length, and cuts the joint portions 33 and 33 into a substantially U-shaped cross section. It has been done.
Such a closing member 10 is welded to the joint portions 33 and 33 of the steel sheet pile 3 so as to be plane-symmetric with the web portion 31 and the flange portions 32 and 32 of the steel sheet pile 3.

Such a closing member 10 (10A, 10B) is directed to the slope 1b side of the embankment 1. That is, the closing member 10 (10A, 10B) is provided so as to protrude from the steel sheet pile 3 toward the outside (the slope 1b side).
The protruding amount (length) t of the closing member 10 from the steel sheet pile 3 is set to 0.01L ≦ t ≦ 0.08L, for example, where L is the length of the slope 1b in the horizontal direction. This is because when t is larger than 0.08L, the resistance when placing the steel sheet pile 3 becomes too large, and when t is smaller than 0.01L, the slope 1b of the embankment 1 as described later sinks. This is because the suppression effect is small.

  In addition, in this Embodiment, although the sheet pile reinforcement member 10 was comprised by the said closing member 10A, 10B, a closing member may be flat.

According to the present embodiment, the portion where the steel sheet pile 3 is greatly deformed at the time of an earthquake is near the boundary surface between the embankment 1 and the embankment foundation ground 2 or below that including the boundary surface. Since the steel sheet pile 3 is reinforced by the sheet pile reinforcing member 10 in the range to include, the steel sheet pile 3 can be effectively reinforced at low cost.
Therefore, the settlement of the whole embankment can be suppressed at a low cost as compared with a reinforcing structure having a conventional partition wall.

  In addition, when the lower end of the steel sheet pile 3 reaches the support layer 2a of the embankment foundation ground 2, the portion where the steel sheet pile 3 is greatly deformed at the time of an earthquake is from the vicinity of the boundary surface position between the embankment 1 and the embankment foundation ground 2. Since it is in the range of 2/5 of the height of the embankment on the ground 2 side, and the sheet pile reinforcing member 10 is arranged in this range, the deformation of the steel sheet pile 3 is efficiently suppressed and the settlement of the embankment 1 is suppressed. Can do.

  Furthermore, two rows of steel sheet pile walls 4 and 4 are provided on the embankment 1 by installing steel sheet piles 3 and 3 in the vicinity of the two shoulders 1c and 1c, respectively, and the closing member 10 is the slope 1b of the embankment 1. , 1b side, so that when the steel sheet pile 3 is placed, the earth and sand closes in the closed section of the closing member 10 and the steel sheet pile 3, and as shown by the arrow in FIG. On the other hand, the slopes (slopes) 1b, 1b of the embankment 2 are about to sink along the steel sheet pile walls 4, 4, and the sinking is supported by the closing portion in the closing section of the closing member 10, and the sinking Can be suppressed.

Further, the steel sheet pile 3 includes a web portion 31 and a pair of flange portions 32 and 32 continuously formed on both sides of the web portion 31, and the sheet pile reinforcing member 10 includes a pair of flange portions 32 and 32 of the steel sheet pile 3. Since the closing member 10 is joined between the tips of 32 and closes the open section of the steel sheet pile 3, the steel sheet pile 3 can be efficiently stiffened while suppressing the degree of processing, and the sheet pile reinforcing member (closing member) 10 can be stiffened. Cost increase accompanying installation can be suppressed.
Furthermore, the closed cross section formed by the closing member 10 and the steel sheet pile 3 is closed when the steel sheet pile is placed. Therefore, the settlement of the embankment at the time of an earthquake can be supported by this block part, and as a result, the settlement of the embankment can be suppressed.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a second embodiment of the present invention.
This second embodiment is different from the first embodiment in that the lower end of the steel sheet pile 3 does not reach the support layer 2a of the embankment foundation ground 2 and remains in the liquefied layer 2b. is there.
Since other configurations are the same as those of the first embodiment, common components are denoted by the same reference numerals, and description thereof is omitted or simplified.

In the second embodiment, as shown in FIG. 2, the lower end of the steel sheet pile 3 reaches only the liquefied layer 2b. And the closing member 10 is arrange | positioned from the boundary surface position vicinity of the embankment 1 and the embankment foundation ground 2 to the embankment foundation ground 2 side at least in the range of 2/5 of embankment height.
In the present embodiment, the sheet pile reinforcing member 10 can effectively reinforce the steel sheet pile 3 at low cost, and since the lower end of the steel sheet pile 3 is not fixed, deformation that occurs in the steel sheet pile 3 during an earthquake is suppressed. The cross section of the sheet pile can be reduced.
Furthermore, since the length of the steel sheet pile 3 can be shortened compared with the steel sheet pile 3 of 1st Embodiment, the steel material cost can be reduced by that much and cost reduction can be aimed at.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a third embodiment of the present invention.
The third embodiment is different from the first and second embodiments in that the lower end of the steel sheet pile 3 does not reach the support layer 2a of the embankment foundation ground 2, but reaches the upper surface of the support layer 2a. This is in contact with the upper surface.
Since other configurations are the same as those of the first and second embodiments, common components are denoted by the same reference numerals, and description thereof is omitted or simplified.

In 3rd Embodiment, as shown in FIG. 3, the lower end of the steel sheet pile 2 penetrates the liquefying layer 2b, and is in contact with the upper surface of the support layer 2a.
Therefore, when the liquefied layer is liquefied by an earthquake, the steel sheet pile 3 is about to sink, whereas the lower end of the steel sheet pile 3 is in contact with the upper surface of the support layer 2a. Can be suppressed.

  Moreover, by expanding the diameter of the lower end of the steel sheet pile 3, the settlement of the steel sheet pile 3 can be suppressed more effectively. In order to increase the diameter of the lower end of the steel sheet pile 3, for example, an auxiliary member formed by cutting the steel sheet piles 3A and 3B into a predetermined length is used as the web portion 31 and the flange portions 32 and 32 of the steel sheet pile 3. You may weld-join to the joint parts 33 and 33 of steel sheet piles 3A and 3B so that it may become plane symmetry.

Moreover, although the length of the steel sheet pile 3 becomes long compared with the steel sheet pile 3 of 2nd Embodiment, since it can shorten compared with the steel sheet pile 3 of 1st Embodiment, it is the steel material by that much. Costs can be reduced and costs can be reduced.
Needless to say, this embodiment can achieve the same effects as those of the first embodiment.

(Fourth embodiment)
FIG. 4 is a sectional view showing a fourth embodiment of the present invention.
The fourth embodiment differs from the first embodiment in that the closing members 10 and 10 are directed between the two rows of steel sheet pile walls 4 and 4.
Since other configurations are the same as those of the first embodiment, common components are denoted by the same reference numerals, and description thereof is omitted or simplified.

  In 4th Embodiment, as shown in FIG. 4, the closing members 10 and 10 protrude toward the inner side from the steel sheet piles 3 and 3. As shown in FIG. Similar to the first embodiment, the closing member 10 is disposed from the vicinity of the boundary surface position between the embankment 1 and the embankment foundation ground 2 to the embankment foundation ground 2 side in a range of at least 2/5 of the embankment height. ing.

In the present embodiment, since the closing member 10 is not directed to the slope 1b side of the embankment 1, the slope (slope) 1b, 1b of the embankment 2 is about to sink at the time of an earthquake. It cannot be supported by the closing part in the closing cross section of the closing member 10.
However, when the steel sheet pile 3 is placed, the earth and sand closes in the closed section of the closing member 10 and the steel sheet pile 3 and the movement of the earth and sand between the two rows of steel sheet pile walls 4 and 4 is restricted. In response to the fact that the entire embankment is going to sink in the subsequent earthquake, the settlement is supported by the closed portion in the closed section, and the movement of the sand between the steel sheet pile walls 4 and 4 of the embankment 1 is restricted. The subsidence can be suppressed.
In the present embodiment, it is needless to say that the same effects as those of the first embodiment can be obtained except for the suppression of settlement of the slopes (slopes) 1b, 1b of the embankment 2.

(Fifth embodiment)
FIG. 5 is a cross-sectional view showing a fifth embodiment of the present invention.
The fifth embodiment is different from the second embodiment in that the closing members 10 and 10 are directed between the two rows of steel sheet pile walls 4 and 4.
Since other configurations are the same as those of the second embodiment, common components are denoted by the same reference numerals, and description thereof is omitted or simplified.

  In 5th Embodiment, as shown in FIG. 5, the closing members 10 and 10 protrude toward the inner side from the steel sheet piles 3 and 3. As shown in FIG. Similar to the first embodiment, the closing member 10 is disposed from the vicinity of the boundary surface position between the embankment 1 and the embankment foundation ground 2 to the embankment foundation ground 2 side in a range of at least 2/5 of the embankment height. ing.

In this embodiment, since the closing member 10 is not directed to the slope 1b side of the embankment 1, the slope (slope) 1b, 1b of the embankment 2 is about to sink due to an earthquake, and the settlement is closed. The member 10 cannot be supported by the closed portion in the closed cross section.
However, when the steel sheet pile 3 is placed, the earth and sand closes in the closed section of the closing member 10 and the steel sheet pile 3 and the movement of the earth and sand between the two rows of steel sheet pile walls 4 and 4 is restricted. In response to the fact that the entire embankment is going to sink in the subsequent earthquake, the settlement is supported by the closed portion in the closed section, and the movement of the sand between the steel sheet pile walls 4 and 4 of the embankment 1 is restricted. The subsidence can be suppressed.
In the present embodiment, it goes without saying that the same effects as those of the second embodiment can be obtained except for the suppression of settlement of the slopes (slopes) 1b, 1b of the embankment 2.

(Sixth embodiment)
FIG. 6 is a cross-sectional view showing a sixth embodiment of the present invention.
The fifth embodiment is different from the third embodiment in that the closing members 10 and 10 are directed between the two rows of steel sheet pile walls 4 and 4.
Since other configurations are the same as those of the third embodiment, common components are denoted by the same reference numerals, and description thereof is omitted or simplified.

  In the sixth embodiment, as shown in FIG. 6, the closing members 10, 10 project inward from the steel sheet piles 3, 3. Similar to the first embodiment, the closing member 10 is disposed from the vicinity of the boundary surface position between the embankment 1 and the embankment foundation ground 2 to the embankment foundation ground 2 side in a range of at least 2/5 of the embankment height. ing.

In this embodiment, since the closing member 10 is not directed to the slope 1b side of the embankment 1, the slope (slope) 1b, 1b of the embankment 2 is about to sink due to an earthquake, and the settlement is closed. The member 10 cannot be supported by the closed portion in the closed cross section.
However, when the steel sheet pile 3 is placed, the earth and sand closes in the closed section of the closing member 10 and the steel sheet pile 3 and the movement of the earth and sand between the two rows of steel sheet pile walls 4 and 4 is restricted. In response to the fact that the entire embankment is going to sink in the subsequent earthquake, the settlement is supported by the closed portion in the closed section, and the movement of the sand between the steel sheet pile walls 4 and 4 of the embankment 1 is restricted. The subsidence can be suppressed.
In the present embodiment, it goes without saying that the same effects as those of the third embodiment can be obtained except for the suppression of the settlement of the slopes (slopes) 1b, 1b of the embankment 2.

In the first to sixth embodiments, the steel sheet pile 3 and the closing member 10 are preferably formed with protrusions 11a, 11b, and 11c as shown in FIGS.
Here, FIG. 9 is a front view showing the steel sheet pile 3 in the first to sixth embodiments, and FIG. 10 is a front view showing the closing member 10 in the first to sixth embodiments.
In FIG. 9, protrusions 11 a are formed by welding and fixing a plurality of rod-shaped steel materials on the inner surface of the web portion 31 in the middle portion in the vertical direction of the steel sheet pile 3, that is, the surface facing the closing member 10. These protrusions 11a are provided within a range of the length L of the closing member 10, that is, at a position that becomes a closed portion when the steel sheet pile 1 is driven on the ground, and are formed orthogonal to the longitudinal direction of the steel sheet pile 3. Has been.

On the other hand, in FIG. 10, on the inner surface of the closing member 10, that is, the surface facing the web portion 31 of the steel sheet pile 3, a plurality of parallel line-shaped protrusions 11b (FIG. 10 (a)) formed by rolling, Alternatively, a plurality of checker-like protrusions 11c (FIG. 10B) formed by rolling are formed. In addition, as parallel line-shaped protrusion 11b of the closing member 10 shown to Fig.10 (a), what fixed the rod-shaped steel material by welding may be used.
If the projections 11a, 11b, and 11c as described above are formed, the friction between the clod that has entered the closed cross-section portion of the closing member 10 and the closing member 10 and the steel sheet pile 3 increases, and the blocking effect of the blocking portion is increased. Can be increased.

Next, in the first to sixth embodiments, the sheet pile reinforcing member (closing member) 10 is applied to the steel sheet pile 3 from the vicinity of the boundary surface position between the embankment 1 and the embankment foundation ground 2 to the embankment foundation ground 2 side. The reason for providing at least in the range of 2/5 of the embankment height will be described.
First, as a model of the embankment reinforcement structure according to the present invention, as shown in FIG. 11, a two-layer ground is manufactured as a foundation foundation ground, a lower layer is a support layer (consolidation layer), and an upper layer is a liquefied layer. . Moreover, embankment was provided on this liquefied layer. The thickness of the support layer, the liquefied layer, and the height of the embankment were all 250 mm.

  And when steel piles (thickness 1.6 mm) were driven in from both shoulders of the embankment and installed so that the lower end reached the inside of the support layer (case C), it was installed so that the lower end reached the liquefied layer. In the case (Case D), a vibration experiment was performed, and the deformation of each steel sheet pile after vibration was measured. In this measurement, a plurality of strain gauges were attached to the sheet pile at predetermined intervals in the vertical direction, and the strain caused by the deformation of the sheet pile was measured by this strain gauge. In addition, the upper ends of the steel sheet piles driven into both shoulders of the embankment were connected by tie rods.

As shown in the graph shown on the right side of FIG. In this case, it was found that the portion with the largest strain, that is, the portion with the largest deformation, is located at a position of about 250 mm from the top of the sheet pile (the upper surface of the embankment).
That is, in the case C, it was found that the portion where the deformation of the steel sheet pile was the largest was a position of 50 mm to 100 mm from the vicinity of the boundary surface between the embankment and the embankment foundation ground to the embankment foundation ground side.
Moreover, in case D, it turned out that it is a position of the boundary surface vicinity of embankment and embankment foundation ground.
Therefore, since the height of the embankment is 250 mm, the sheet pile reinforcing member is at least 2/5 (100/250) of the embankment height from the vicinity of the boundary surface position between the embankment and the embankment foundation ground to the embankment foundation ground side. (Closed member) decided to provide.

  In addition, as shown in FIG. 12, in the embankment reinforcement structure model, a sheet pile reinforcement member (closing member) 10 is attached to the steel sheet pile 3 from the vicinity of the boundary surface between the embankment 1 and the embankment foundation ground 2. In addition, a vibration test was performed in the case where it was provided at least in the range of 2/5 (100/250) of the height of the embankment and in the case where the sheet pile reinforcing member (closing member) was not provided, and the slope of the embankment 1 (slope) ) When the amount of subsidence of 1b and 1b was examined, as shown in FIG. 12 (a), the case where the sheet pile reinforcing member (closing member) 10 is provided is compared with the case where it is not provided as shown in FIG. 12 (b). Thus, it was found that the amount of settlement on the slopes 1b and 1b was small.

DESCRIPTION OF SYMBOLS 1 Embankment 2 Embankment foundation ground 2a Support layer 2b Liquefaction layer 3 Steel sheet pile 4 Steel sheet pile wall 10 Sheet pile reinforcement member (closure member)
11a, 11b, 11c Projection 31 Web portion 32 Flange portion 33 Joint portion

Claims (6)

In the continuous embankment provided on the embankment foundation ground composed of the liquefaction layer and the lower support layer , the lower end is in the liquefaction layer of the embankment foundation ground or up to the upper surface of the support layer In the reinforcement structure of the embankment in which a steel sheet pile wall made of a steel sheet pile reaching or in the support layer is provided along the continuous direction of the embankment,
In the steel sheet pile, a sheet pile reinforcing member is provided in a range including a boundary surface position between the embankment and the embankment foundation ground,
The steel sheet pile includes a web portion, a pair of flange portions formed continuously on both sides of the web portion, and a joint portion formed on the tip side of the pair of flange portions,
The embankment reinforcing structure , wherein the sheet pile reinforcing member is a closing member that is joined between the ends of a pair of flange portions of the steel sheet pile and closes an open section of the steel sheet pile .   The said sheet pile reinforcing member is arrange | positioned in the range of at least 2/5 of the said embankment height from the boundary surface position vicinity of the said embankment and the said embankment foundation ground to the said embankment foundation ground side. The embankment reinforcement structure according to 1. The embankment reinforcing structure according to claim 1 , wherein the closing member has a substantially U-shaped cross section that is plane-symmetric with respect to the web portion and the flange portion of the steel sheet pile. By installing the steel sheet piles near the two shoulders on the embankment, two rows of the steel sheet pile walls are provided,
4. The embankment reinforcing structure according to claim 3 , wherein the closing member is directed to a slope side of the embankment. By installing the steel sheet piles near the two shoulders on the embankment, two rows of the steel sheet pile walls are provided,
4. The embankment reinforcing structure according to claim 3 , wherein the closing member is directed between two rows of the steel sheet pile walls. The embankment reinforcement structure using the steel sheet pile according to any one of claims 1 to 5 , wherein a projection is formed on a surface of the closing member facing the steel sheet pile.

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