JP2010209528A - Lateral flow countermeasure structure - Google Patents

Abstract

[PROBLEMS] To prevent damage to a structure of lateral flow caused by liquefaction of ground due to an earthquake, thereby reducing costs and labor.
A plurality of underground walls 2 in a direction parallel to a normal line of a revetment 13 are provided in a back ground 14 between the revetment 13 and a building 15 at a predetermined distance d in a direction along a side surface of the revetment 13. The disposition wall 3 is constructed in such a manner that the disposition wall 3 is perpendicular to the central portion of the plurality of underground walls 2 and the lower end portion 3a is embedded in the non-liquefaction layer 12. The underground wall 2 has a lower end 2a reaching the non-liquefied layer 12 in the ground and sufficiently rooted in the non-liquefied layer inner wall 21 and the lower end 2a is a liquefied layer in the ground. 11 and the liquefied layer inner wall 22 are arranged alternately.
[Selection] Figure 1

Description

  The present invention relates to a lateral flow countermeasure structure for reducing damage to a lateral flow structure caused by ground liquefaction due to an earthquake.

As is well known, the dangers of Tokai, Tonankai, Nankai earthquakes and earthquakes directly under the Tokyo metropolitan area have been screamed. For example, in power, oil plants and factories located on the landfills in the coastal areas, Measures are being taken to reduce damage to buildings and foundations due to lateral flow associated with liquefaction.
Lateral flow near the revetment due to earthquake liquefaction is a phenomenon in which the liquefied ground behind it becomes fluidized as the seabed ground liquefies and the bearing capacity is lost and the revetment is displaced to the sea. It is. Therefore, it is possible to reduce damage to buildings and foundations by taking measures to prevent the revetment from colliding with the building behind it.

Therefore, as a countermeasure against the lateral flow of the ground behind the revetment, for example, a density increasing method for increasing and improving the density of the ground such as a sand compaction pile in the back ground, an excessive pore water pressure dissipation method such as gravel drain, Solidification methods such as injecting cement-based materials and chemicals into the ground are being carried out.
However, with the density increasing processing method such as sand compaction pile, displacement may occur in the surrounding ground, such as the uplift of the construction ground due to improvement, so it is difficult to apply it around the existing structure, and the gravel drain In such an excessive pore water pressure dissipation method, if the earthquake input exceeds the design value even a little, the effect of suppressing the water pressure suddenly disappears, so that the effect cannot be expected when an earthquake more than expected occurs. Further, there has been a problem that cost and labor are required for the entire improvement by the solidification method.

Therefore, according to Patent Document 1, a plurality of underground walls rooted in the non-liquefaction layer in a direction perpendicular to the side surface of the structure to the ground around the structure are arranged along the side surface of the structure. A ground side flow countermeasure structure has been proposed that can prevent the side flow from being damaged even if the revetment collapses due to ground liquefaction caused by an earthquake. Yes. In addition, a plurality of underground walls rooted in the non-liquefaction layer are arranged at predetermined intervals in the direction along the revetment in the direction perpendicular to the revetment to the ground below the water side of the revetment. In addition, a side flow countermeasure revetment structure that prevents the revetment from moving to the water side due to liquefaction of the ground due to an earthquake has been proposed. The underground wall is, for example, a ground improvement body formed into a wall shape by a ground improvement method.
As described above, in the structure in which a plurality of underground walls rooted in the non-liquefied layer are arranged at predetermined intervals in the ground, the improvement volume is reduced as compared with the solidification method for improving the ground entirely. Therefore, cost reduction and labor reduction can be performed.

Japanese Patent Laid-Open No. 10-219676

  However, a plurality of underground walls such as a conventional ground lateral flow countermeasure structure according to Patent Document 1 and a lateral flow countermeasure bank revetment structure in which a plurality of underground walls are disposed on the ground below the water side of the revetment are non-liquid. Even in a structure that is sufficiently embedded in the formation layer, further cost reduction and labor reduction are desired.

  The present invention has been made in view of the above-mentioned problems, and can reduce damage to the structure of the lateral flow caused by the liquefaction of the ground due to the earthquake, and the lateral flow that can realize cost reduction and labor reduction. The purpose is to provide a countermeasure structure.

In order to achieve the above object, the lateral flow countermeasure structure according to the present invention includes a plurality of first parallel parallel to the revetment normal in the ground between the revetment and a structure disposed on the ground behind the revetment. The underground walls are arranged at predetermined intervals in the direction along the side of the revetment, and the second underground wall is arranged with a plurality of first underground walls in a direction intersecting the first underground wall. The lower end of part of the first underground wall and the second underground wall is embedded in the non-liquefaction layer, and the lower end of the others is non-exposed. It is characterized by not being embedded in the liquefied layer.
In the present invention, the lower ends of the first underground wall and the second underground wall disposed in the ground between the revetment and the structure are rooted in the non-liquefaction layer. Therefore, even if the revetment is displaced to the water side and lateral flow occurs, the ground on the revetment side of the structure is not attached to the first and second underground walls. It is restrained, the displacement of the structure can be prevented, and damage caused to the structure can be reduced.
The first underground wall and the part of the second underground wall are a part of a plurality of first underground walls, a whole of a plurality of first underground walls, or a second underground wall or a plurality of underground walls. A part of the first underground wall and the second underground wall are shown.
Compared to the conventional lateral flow countermeasure structure in which the lower end of all underground walls are embedded in the non-liquefied layer, the first underground wall and the Except for a part of the second underground wall, the lower end portion thereof is not embedded in the non-liquefaction layer, and the total volume of the underground wall can be reduced, so that cost and labor can be reduced.

Further, in the lateral flow countermeasure structure according to the present invention, the plurality of first underground walls have a first underground wall and a lower end part in the liquefied layer whose lower end part is embedded in the non-liquefied layer. It is good also as a structure by which a certain 1st underground wall is arranged by turns.
In the present invention, the first underground wall in which the lower end portion is embedded in the non-liquefied layer and the first underground wall in which the lower end portion is in the liquefied layer are alternately arranged, so that the structure The displacement of the object can be prevented, and the total volume of the first underground wall can be reduced, thereby reducing the cost and labor.

Moreover, in the lateral flow countermeasure structure according to the present invention, the second underground wall may be disposed orthogonal to the center of the plurality of first underground walls.
In the present invention, the second underground wall is orthogonal to the center of the plurality of first underground walls, thereby restraining the plurality of first underground walls, so that the ground flow can be suppressed.

In the lateral flow countermeasure structure according to the present invention, the second underground wall may be disposed on the side of the first underground wall on the structure side.
In the present invention, since the second underground wall is reinforced by a plurality of first underground walls against the external force in the direction from the back ground side to the revetment due to lateral flow, the revetment of the structure The ground on the side is constrained, the displacement of the structure can be prevented, and damage caused to the structure can be reduced.

In the lateral flow countermeasure structure according to the present invention, the first and second underground walls are preferably ground improvement bodies formed by a ground improvement method.
In the present invention, since the first and second underground walls are ground improvement bodies integrated with the liquefied layer and the non-liquefied layer in the ground, the displacement of the liquefied layer around the underground wall is restrained. Since the underground wall embedded in the non-liquefied layer is firmly supported by the non-liquefied layer, damage caused to the structure due to lateral flow can be reduced.

  According to the present invention, a part or all of the plurality of first underground walls arranged in the ground between the revetment and the structure, or at least one of the second underground walls is underground. Since the lower end of the wall is embedded in the non-liquefaction layer, even if the revetment is displaced due to lateral flow due to the liquefaction of the ground due to the earthquake, the structure and revetment are separated by the first and second underground walls. Can constrain the ground between them, prevent displacement of the structure, reduce the damage caused to the structure by lateral flow, reduce the total volume of the underground wall, reduce cost and labor Can be achieved.

(A) is a figure which shows an example of the side flow countermeasure structure by 1st embodiment of this invention, (b) is a top view of the side flow countermeasure structure shown to (a), (c) is (b) It is an AA sectional view taken on the line. (A) is a figure which shows an example of the side flow countermeasure structure by 1st embodiment of this invention, (b) is a top view of the side flow countermeasure structure shown to (a), (c) is (b) It is a BB sectional view taken on the line. (A) is a figure which shows an example of the side flow countermeasure structure by 1st embodiment of this invention, (b) is a top view of the side flow countermeasure structure shown to (a), (c) is (b) It is a CC sectional view taken on the line. (A) is a figure which shows an example of the side flow countermeasure structure by 1st embodiment of this invention, (b) is a top view of the side flow countermeasure structure shown to (a), (c) is (b) It is the DD sectional view taken on the line. (A) is a top view which shows the modification of the side flow countermeasure structure by 1st embodiment of this invention, (b) is the EE sectional view taken on the line of (a). (A) is a top view which shows the other modification of the side flow countermeasure structure by 1st embodiment of this invention, (b) is the FF sectional view taken on the line of (a). (A) is a top view which shows the modification of the side flow countermeasure structure by 2nd embodiment of this invention, (b) is the GG sectional view taken on the line (a). (A) is a top view which shows the other modification of the side flow countermeasure structure by 2nd embodiment of this invention, (b) is the HH sectional view taken on the line of (a). (A) is a top view which shows the modification of the side flow countermeasure structure by 3rd embodiment of this invention, (b) is the II sectional view taken on the line of (a). (A) is a top view which shows the other modification of the side flow countermeasure structure by 3rd embodiment of this invention, (b) is the JJ sectional view taken on the line of (a). (A) is a top view which shows the further another modification of the side flow countermeasure structure by 3rd embodiment of this invention, (b) is the KK sectional view taken on the line of (a). (A) is a top view which shows the modification of the side flow countermeasure structure by 1st embodiment of this invention, (b) is the LL sectional view taken on the line of (a). (A) is a top view which shows the other modification of the side flow countermeasure structure by 3rd embodiment of this invention, (b) is the JJ sectional view taken on the line of (a). (A) is a top view which shows the further another modification of the side flow countermeasure structure by 3rd embodiment of this invention, (b) is the KK sectional view taken on the line of (a).

Hereinafter, the lateral flow countermeasure structure according to the first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 (a) to (c), in the case of water W such as the sea or river in the ground where the liquefied layer 11 exists in the surface layer portion and the non-liquefied layer 12 exists below the surface layer, An existing sheet pile type revetment 13 is provided. The revetment 13 is a wall-shaped steel sheet pile structure formed long along the boundary portion between the water W and the back ground 14, the upper end is higher than the liquid level of the water W, and the lower end is the bottom of the water W. To the non-liquefied layer 12 following the formation. An existing building 15 is disposed in the vicinity of the revetment 13, and the building 15 includes a pile foundation 16, and a lower end portion of the pile foundation 16 reaches the non-liquefied layer 12.
The lateral flow countermeasure structure 10a according to the first embodiment includes a plurality of buttress-like underground walls 2 constructed in the back ground 14 between the revetment 13 and the building 15, It is comprised roughly from the arrangement | positioning wall 3 which intersects.

The underground wall 2 is made of a wall-like cement-based improved body formed by ground improvement, and is arranged in a direction parallel to the normal line of the revetment 13. The underground wall 2 has a lower end 2a reaching the non-liquefied layer 12 in the ground and sufficiently rooted in the non-liquefied layer inner wall 21 and the lower end 2a is liquefied in the ground. There is a liquefied layer inner wall 22 in the layer 11, the non-liquefied layer inner wall 21 and the liquefied layer inner wall 22 are alternately arranged, and the adjacent non-liquefied layer inner wall 22 A predetermined distance d is provided between 21 and the liquefied layer inner wall 22 in the direction along the side surface of the revetment 13.
And these underground walls 2 are arranged over the range wider than the width | variety of the direction along the side surface of the revetment 13 of the building 15. As shown in FIG. The underground wall 2 is spaced between the revetment 13 and the building 15, and the upper end 2 b reaches the vicinity of the surface of the back ground 14.

  The arrangement wall 3 is made of a wall-like cement-based improvement body formed by ground improvement, and extends to a length connecting a plurality of arranged underground walls 2 perpendicular to the center of the underground wall 2. Yes. The lower end 3 a of the disposition wall 3 is sufficiently embedded in the non-liquefied layer 12, and the upper end 3 b reaches the vicinity of the surface of the back ground 14.

Next, the effect of the side flow countermeasure structure according to the first embodiment will be described with reference to the drawings.
In the lateral flow countermeasure structure 10a according to the first embodiment, the plurality of underground walls 2 are constrained by the arrangement walls 3, and the non-liquefied layer inner wall 21 and the arrangement walls 3 are non-liquefied. Since it is in a stable state that is rooted in the layer 12 and supported by the non-liquefaction layer 12, the ground between the revetment 13 and the building 15 can be firmly restrained, and the ground is liquefied by an earthquake. Even if 13 is displaced to the water W side and a lateral flow occurs, the displacement of the building 15 can be prevented, and the effects that can reduce the damage caused to the building 15 can be achieved.

  Compared with the conventional lateral flow countermeasure structure 10a according to the first embodiment, the non-liquefied layer is compared with the conventional lateral flow countermeasure structure 10a in which all the underground walls and the disposition walls are embedded in the non-liquefied layer 12. Since the inner wall 21 and the inner wall 22 in the liquefaction layer are alternately arranged, the total volume of the underground wall 2 and the installation wall 3 can be reduced, and the construction period can be shortened by cost reduction and construction reduction. Can be realized.

Next, the second embodiment will be described with reference to the accompanying drawings, but the same or similar members and parts as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. A configuration different from that of the embodiment will be described.
As shown in FIGS. 2A to 2C, the lateral flow countermeasure structure 10b according to the second embodiment is provided in the lateral flow countermeasure structure 10a according to the first embodiment shown in FIG. Instead of the wall 3, a side wall 31 of a wall-shaped cement-based improvement body formed by ground improvement is disposed on the side surface 2 c of the underground wall 2 on the building 15 side.
The side wall 31 is disposed in contact with the side surface 2c of the underground wall 2 so that the lower end 31a is embedded in the non-liquefied layer 12 and extends to a length connecting both ends of the plurality of underground walls 2 arranged. Has been.

In the lateral flow countermeasure structure 10b according to the second embodiment, the side wall 31 is in contact with the non-liquefied layer inner wall 21 and the liquid in response to the external force in the direction from the back ground 14 side toward the revetment 13 due to lateral flow. Since the structure is reinforced by the inner wall 22 of the formation layer, the ground on the side of the revetment 13 of the building 15 is restrained, and displacement of the ground around the building 15 is prevented to reduce damage caused to the building 15. There are effects that can be achieved.
Moreover, like the side flow countermeasure structure 10a according to the first embodiment, the total volume of the underground wall 2 and the side wall 31 can be reduced, and the construction period can be shortened by cost reduction and construction reduction.

Next, the third embodiment will be described with reference to the accompanying drawings. However, the same or similar members and parts as those of the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted. A configuration different from the form will be described.
As shown in FIGS. 3A to 3C, in the lateral flow countermeasure structure 10c according to the third embodiment, the arrangement wall of the lateral flow countermeasure structure 10a according to the first embodiment shown in FIG. Instead of 3, a disposition wall 32 is disposed in which the lower end portion 32 a is not embedded in the non-liquefied layer 12 and is disposed in the liquefied layer 11.

In the lateral flow countermeasure structure 10 c according to the third embodiment, the arrangement wall 32 is not rooted in the non-liquefied layer 12, but the non-liquefied layer root wall 21 is rooted in the non-liquefied layer 12. Therefore, the same effects as those of the lateral flow countermeasure structure 10a according to the first embodiment can be obtained.
Moreover, since the underground wall 22 and the disposition wall 32 in the liquefied layer do not penetrate into the non-liquefied layer 12 and have a height up to the liquefied layer 11, the amount of ground improvement can be reduced, thereby reducing costs and construction. The construction period can be shortened.

Next, the fourth embodiment will be described with reference to the accompanying drawings, but the same or similar members and parts as those of the above-described embodiments will be denoted by the same reference numerals, and the description thereof will be omitted. A configuration different from the form will be described.
As shown in FIGS. 4A to 4C, in the side flow countermeasure structure 10d according to the fourth embodiment, the side wall 31 of the side flow countermeasure structure 10b according to the second embodiment shown in FIG. Instead, the side wall 33 is provided in which the lower end portion 33 a is not embedded in the non-liquefied layer 12 and is disposed in the liquefied layer 11.

  In the side flow countermeasure structure 10d according to the fourth embodiment, the side wall 33 is not rooted in the non-liquefied layer 12, but the non-liquefied layer root wall 21 is rooted in the non-liquefied layer 12. Therefore, the same effects as those of the side flow countermeasure structure 10b according to the second embodiment are achieved.

  Moreover, since the underground wall 22 and the side wall 33 in the liquefied layer do not penetrate into the non-liquefied layer 12 and have a height up to the liquefied layer 11, the amount of ground improvement can be reduced, and the construction period is reduced by cost reduction and construction reduction. Shortening can be realized.

  Next, modifications of the above-described embodiments will be described with reference to the accompanying drawings. However, the same or similar members and parts as those of the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted. A configuration different from that of the embodiment will be described.

In the lateral flow countermeasure structure 10e shown in FIGS. 5 (a) and 5 (b), the non-liquefied layer inner wall 21 and the liquefied layer inner ground provided in the lateral flow countermeasure structure 10a according to the first embodiment are used. Without arranging the walls 22 alternately, the non-liquefied layer inner wall 21 is arranged at the center and both ends, and the liquefied layer inner wall 22 is arranged between them.
In the lateral flow countermeasure structure 10f shown in FIGS. 6 (a) and 6 (b), the non-liquefied layer inner wall 21 and the liquefied layer interior in the lateral flow countermeasure structure 10a according to the first embodiment are provided. In this configuration, the walls 22 are not alternately arranged but the non-liquefied layer inner wall 21 is installed at both ends, and the liquefied layer inner walls 22 are arranged therebetween.

In the lateral flow countermeasure structure 10g shown in FIGS. 7 (a) and 7 (b), the non-liquefied layer inner wall 21 and the liquefied layer interior in the side flow countermeasure structure 10b according to the second embodiment are provided. Without arranging the walls 22 alternately, the non-liquefied layer inner wall 21 is arranged at the center and both ends, and the liquefied layer inner wall 22 is arranged between them.
In the lateral flow countermeasure structure 10h shown in FIGS. 8 (a) and 8 (b), the non-liquefied layer inner wall 21 and the liquefied layer interior in the lateral flow countermeasure structure 10b according to the second embodiment are provided. In this configuration, the walls 22 are not alternately arranged but the non-liquefied layer inner wall 21 is installed at both ends, and the liquefied layer inner walls 22 are arranged therebetween.

In the lateral flow countermeasure structure 10i shown in FIGS. 9 (a) and 9 (b), the non-liquefied layer inner wall 21 and the liquefied layer interior in the side flow countermeasure structure 10c according to the third embodiment are provided. Without arranging the walls 22 alternately, the non-liquefied layer inner wall 21 is arranged at the center and both ends, and the liquefied layer inner wall 22 is arranged between them.
In the lateral flow countermeasure structure 10j shown in FIGS. 10 (a) and 10 (b), the non-liquefied layer inner wall 21 and the liquefied layer interior in the lateral flow countermeasure structure 10c according to the third embodiment are provided. In this configuration, the walls 22 are not alternately arranged but the non-liquefied layer inner wall 21 is installed at both ends, and the liquefied layer inner walls 22 are arranged therebetween.
In the side flow countermeasure structure 10k shown in FIGS. 11 (a) and 11 (b), the non-liquefied layer inner wall 21 and the inside of the liquefied layer provided in the side flow countermeasure structure 10c according to the third embodiment. It is the structure which makes the underground wall 2 all the non-liquefaction layer rooting underground walls 21 without arranging the wall 22 alternately.

In the side flow countermeasure structure 10l shown in FIGS. 12 (a) and 12 (b), the non-liquefied layer inner wall 21 and the inside of the liquefied layer in the side flow countermeasure structure 10d according to the fourth embodiment are provided. Without arranging the walls 22 alternately, the non-liquefied layer inner wall 21 is arranged at the center and both ends, and the liquefied layer inner wall 22 is arranged between them.
In the lateral flow countermeasure structure 10j shown in FIGS. 13 (a) and (b), the non-liquefied layer inner wall 21 and the liquefied layer inner ground provided in the lateral flow countermeasure structure 10d according to the fourth embodiment are provided. In this configuration, the walls 22 are not alternately arranged but the non-liquefied layer inner wall 21 is installed at both ends, and the liquefied layer inner walls 22 are arranged therebetween.
In the lateral flow countermeasure structure 10k shown in FIGS. 14 (a) and 14 (b), the non-liquefied layer inner wall 21 and the liquefied layer interior in the lateral flow countermeasure structure 10d according to the fourth embodiment are provided. In this configuration, the walls 22 are not arranged alternately, and the underground walls 2 are all made into non-liquefied layer roots.
Each of the lateral flow countermeasure structures described above is selected according to various conditions such as the shape and strength of the revetment 13, the building 15, the back ground 14 and the like.

As mentioned above, although embodiment of the side flow countermeasure structure by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, the lateral flow countermeasure structure 10e according to the modification of the first embodiment described above, the lateral flow countermeasure structure 10g according to the modification of the second embodiment, and the side according to the modification of the third embodiment. In the flow countermeasure structure 10i and the lateral flow countermeasure structure 10l according to the modification of the fourth embodiment, the non-liquefied layer basement underground walls 21 are arranged at the center and both ends of the plurality of underground walls, The inner wall 22 of the liquefied layer is arranged on the wall, but the non-liquefied layer inner wall 21 is placed in an arbitrary place according to the shape and strength of the revetment 13, the building 15, the back ground 14 and the like. The liquefied layer inner wall 22 may be arranged in the other portion.
In addition, all the underground walls 2 provided in the side flow countermeasure structure 10f according to the modification of the first embodiment and the side flow countermeasure structure 10h according to the modification of the second embodiment are all in the liquefied layer interior. The inner wall 22 may be used.
In the above embodiment, the underground wall 2, the disposition walls 3 and 32, and the side walls 31 and 33 are wall-shaped ground improvement bodies. For example, columnar ground improvement bodies are arranged in a wall shape. Alternatively, a wall-like sheet pile may be used instead of the ground improvement body.
In short, it is only necessary to obtain the desired function in the present invention.

2 Underground wall 2a Lower end 2c Side surface 3, 32 Arrangement wall 3a, 32a Lower end 10a Lateral flow countermeasure structure 11 Liquefaction layer 12 Non-liquefaction layer 13 Revetment 14 Back ground 15 Building 21 Non-liquefaction layer penetration Underground wall 22 Underground wall 31, 33 Side wall 31a, 33a Lower end portion d interval W Water

Claims (5)

In the ground between the revetment and a structure disposed on the ground behind the revetment, a plurality of first underground walls parallel to the normal of the revetment have a predetermined direction in a direction along the side of the revetment. Arranged at intervals, and a second underground wall is arranged in a direction intersecting the first underground wall over an arrayed range of the plurality of first underground walls,
The lower end of a part of the first underground wall and the second underground wall is embedded in the non-liquefied layer, and the other lower end thereof is not embedded in the non-liquefied layer. Side flow countermeasure structure characterized by.   In the plurality of first underground walls, the first underground wall whose lower end is embedded in the non-liquefied layer and the first underground wall whose lower end is in the liquefied layer are alternately arranged. The lateral flow countermeasure structure according to claim 1, wherein the lateral flow countermeasure structure is arranged in a horizontal direction.   3. The lateral flow countermeasure structure according to claim 1, wherein the second underground wall is disposed orthogonal to the center of the plurality of first underground walls.   The lateral flow countermeasure structure according to claim 1 or 2, wherein the second underground wall is disposed on a side of the first underground wall on the structure side.   The lateral flow countermeasure structure according to any one of claims 1 to 4, wherein the first and second underground walls are ground improvement bodies formed by a ground improvement construction method.

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