JP2002180480A - Revetment structure for resisting lateral flow - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a revetment structure allowing effective measures against lateral flow due to ground liquefaction caused by an earthquake or the like, while being easy to construct a reduced cost because of the use of no caissons. SOLUTION: The revetment structure for resisting lateral flow 1 is designed to take measures against lateral flow due to ground liquefaction caused by an earthquake or the like. An earth-retaining wall 3 of L-shaped vertical cross section which consists of an upright wall 5 positioned between back ground 4 and water 2 and a heel plate 6 extending from the lower portion of the upright wall 5 to the back gourd 4 is provided between the back ground 4 and the water 2, with the lower end portion 5a of the upright wall 5 disposed to reach a non-liquefied layer 7 in the ground. The heel plate 6 is provided on its bottom surface with a shear cotter 8 reaching the non-liquefied layer 7 in the ground and backfilling for the upright wall 5 is provided, thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a revetment structure such as a sea or a river, and more particularly to a revetment structure in which a countermeasure is taken against lateral flow caused by liquefaction of the ground due to an earthquake or the like.

[0002]

2. Description of the Related Art Conventionally, a caisson-type seawall structure has been known as a seawall structure for a sea or a river. This caisson-type revetment structure is provided with displacement sand at the bottom of the water side such as the sea and rivers, and after raising dumping stones thereon, a box-shaped caisson is placed on this dumping stone, thereby supporting the ground behind It is intended to be.

However, such a caisson-type seawall structure has a problem in that the caisson is inevitably deformed at the time of a strong earthquake, so that the ground behind the lateral wall flows. Therefore, various countermeasures have conventionally been taken to deal with such a problem. For example,
There are (1) a method of improving the ground at the bottom and the ground behind the caisson, and (2) a method of using a considerably large and heavy caisson as an earthquake-resistant seawall.

[0004]

However, (1)
The method of improving the ground has little effect unless the improvement range is widened to some extent, and there is a disadvantage that the construction is difficult when the structures are close to each other.

In the method (2), the use of a large and heavy caisson requires a great deal of cost, and if the caisson slides or falls due to a strong earthquake, there is a complaint that it is difficult to recover.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an effective countermeasure against a lateral flow caused by liquefaction of the ground due to an earthquake or the like.
Moreover, it is an object of the present invention to provide a revetment structure which has good workability and can be inexpensively constructed without using a caisson.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained the following findings. In other words, in the caisson-type revetment structure, as a case of being damaged by lateral flow during an earthquake,
(1) The case where the liquefied soil behind the caisson moves the caisson by pushing the caisson (moves due to the earth pressure during an earthquake). (2) The caisson moves by inertia force. There are two cases, that is, the case where the ground moves behind the ground. In the 1995 Southern Hyogo Earthquake, investigations reported that case (2) was dominant. Therefore, the present inventor assumed that the case (2) mainly occurs during an earthquake, and considered that it is effective to prevent this, and completed the present invention.

[0008] That is, the revetment structure for lateral flow countermeasures of the present invention is a revetment structure in which countermeasures against lateral flow due to liquefaction of the ground due to an earthquake or the like are provided, and between the back ground side and the water side. An upright wall to be arranged, a mountain retaining retaining wall having a vertical cross section L-shaped and comprising a heel plate extending from the lower portion of the upright wall to the back ground side is provided between the back ground side and the water side, The lower end of the upright wall is disposed so as to reach the non-liquefied layer in the ground, and the heel plate is provided with a shear cotter that reaches the non-liquefied layer in the ground on the bottom surface thereof. The above-mentioned problem is solved by backfilling the upright wall.

According to the revetment structure for preventing lateral flow, the caisson is not used, so that the caisson does not move due to the inertial force during an earthquake, and the ground behind does not move. In addition, the "discarded stone" and "replacement sand" that were constructed on the bottom of the caisson are no longer necessary. In addition, the lower end of the upright wall is disposed so as to reach the non-liquefied layer in the ground, and a shear cotter that reaches the non-liquefied layer in the ground is provided on the bottom of the heel plate, Even in the event of a strong earthquake or the like, even if the back ground side causes lateral flow, the retaining wall itself is prevented from protruding to the water side. Furthermore, since the backing is performed on the heel plate with respect to the upright wall, the weight of the backing stabilizes the posture of the retaining wall and prevents the falling of the retaining wall.

Further, if the length of the heel plate is made longer than the height of the upright wall, the weight of the back-filling on the heel plate becomes larger, and the retaining wall for the mountain stay becomes more stable and the overturn can be performed more reliably. Is prevented. In addition, if a buttress for reinforcing the upright wall is provided on the inner corner formed by the upright wall and the heel plate, it becomes possible to further increase the bending strength of the upright wall, and thus, for example, against lateral flow on the back ground side. Even so, the bearing capacity for this is greater.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
FIG. 1 is a view showing one embodiment of a lateral flow countermeasure seawall structure of the present invention. In FIG. 1, reference numeral 1 denotes a lateral flow countermeasure seawall structure (hereinafter abbreviated as a seawall structure). The revetment structure 1 is a structure formed near the water 2 such as the sea or a river, and mainly includes a retaining wall 3 having an L-shaped vertical section.

The retaining wall 3 is composed of the water 2 side and the back ground 4
This is an L-shaped concrete structure having a vertical section (side section) composed of an upright wall 5 disposed between the side wall and a heel plate 6 extending from the lower portion of the upright wall 5 to the back ground 4 side. . The upright wall 5 is formed to be long along the boundary between the water 2 and the back ground 4, the upper end thereof is formed sufficiently higher than the liquid surface (water surface) of the water 2, and the lower end 5a thereof.
Are formed to reach the non-liquefied layer 7 following the bottom stratum on the water 2 side.

The heel plate 6 is disposed substantially horizontally at a lower portion of the upright wall 5, that is, slightly above the lower end thereof, and reaches the non-liquefied layer 7 on the bottom surface. A plurality of shear cotters 8 are provided. These shear cotters 8 are formed and arranged substantially parallel to the length direction of the upright wall 5. When a pressure is applied to the upright wall 5 toward the water 2 due to lateral flow during a strong earthquake, the shear cotter 8 becomes non-liquefied. By being held by the layer 7, the mountain retaining wall 3 is prevented from protruding toward the water 2.

The heel plate 6 is provided on the surface of the non-liquefied layer 7 in this embodiment, and is backfilled by burying or backfilling soil or the like. It is in a state of being left. In addition, the site | part formed by such landfill or backfilling in the back ground 4 is the liquefied layer 9. FIG. here,
It is preferable that the length L of the heel plate 6 of the present invention is longer than the height H of the upright wall 5, and if it is formed in this manner, the soil covering the heel plate 6 (backfill soil) ) Is larger, the posture of the retaining wall 3 is more stable, and the fall thereof can be more reliably prevented.

In such a revetment structure 1, since the caisson is not used, it is possible to prevent the caisson from moving due to the inertial force during an earthquake and the ground behind it being moved. In addition, it is not necessary to use "discarded stone" or "replacement sand" that had been constructed on the bottom of the caisson, so construction can be performed at low cost. In addition, the lower end 5a of the upright wall 5 is disposed so as to reach the non-liquefied layer 7 in the ground, and the shear cotter 8 that reaches the non-liquefied layer 7 on the bottom of the heel plate 6 is provided. In the event of a strong earthquake, even if the ground 4 behind
The mountain retaining wall 3 itself can be reliably prevented from protruding toward the water 2. Furthermore, since the backing or backfilling is performed on the heel plate 6 as backing to the upright wall 5, the weight of the soil and the like stabilizes the posture of the retaining wall 3 so that the fall can be prevented even during a strong earthquake. Can be prevented.

FIG. 2 is a view showing another example of reinforcement of the mountain retaining wall used in the revetment structure 1 shown in FIG. 1, and reference numeral 10 in FIG. 2 is a mountain retaining wall. This mountain retaining wall 10 differs from the mountain retaining wall 3 shown in FIG. 1 in that a buttress 11 is provided for reinforcement. That is, the buttress retaining wall 10 shown in FIG. 2 is provided with a plurality of buttresses 11 for reinforcing the upright wall 5 on the inner angle side (the acute angle side) formed by the upright wall 5 and the heel plate 6. These bad dresses 11 ...
Is a concrete structure formed so as to be continuous with both the upright wall 5 and the heel plate 6 and arranged mainly at predetermined intervals to mainly reinforce the bending strength of the upright wall 5. It is. With such a configuration, in the seawall structure using the mountain retaining wall 10 shown in FIG. 2, for example, the revetment structure having a greater resistance to the lateral flow on the back ground side is used. Becomes

[0017]

As described above, the side wall flow protection revetment structure of the present invention employs a structure that does not use a caisson, so that the caisson moves due to inertial force during an earthquake, thereby causing the caisson to move behind. It is possible to prevent the ground from moving, and it is not necessary to use "discarded stones" or "replacement sand" that had been constructed on the bottom of the caisson, so construction can be performed at low cost. In addition, since the lower end of the upright wall reaches the non-liquefied layer in the ground and is provided, and a shear cotter that reaches the non-liquefied layer on the bottom of the heel plate is provided, in the event of a strong earthquake, etc. Even if the back ground side flows laterally, the retaining wall itself can be reliably prevented from protruding to the water side. In addition, since the heel plate is buried or backfilled as a backfill against the upright wall, the weight of these soils etc. stabilizes the posture of the retaining wall and prevents it from falling even during a strong earthquake etc. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining an embodiment of a lateral flow countermeasure seawall according to the present invention.

FIG. 2 is a perspective view showing another example of reinforcement of a mountain retaining wall used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Side flow countermeasure revetment structure, 2 ... Water, 3 ... 10 ... Retaining wall, 4 ... Behind ground, 5 ... Upright wall, 5a ... Lower end, 6 ...
Heel plate, 7 ... non-liquefied layer, 8 ... shear cotter, 9 ...
Liquefied layer, 11 ... buttress.

Claims (3)

[Claims] 1. A revetment structure which takes measures against lateral flow accompanying liquefaction of the ground due to an earthquake or the like, comprising: an upright wall disposed between a back ground side and a water side; An L-shaped mountain retaining wall having a vertical cross section composed of a heel plate extending from the lower part to the back ground side is provided between the back ground side and the water side, and a lower end of the upright wall is a non-liquid in the ground. The heel plate is provided with a shear cotter that reaches the non-liquefied layer in the ground, and the heel plate is back-filled to the upright wall. The revetment structure against lateral flow is characterized. 2. The revetment structure for preventing lateral flow according to claim 1, wherein the length of the heel plate is longer than the height of the upright wall. 3. The revetment structure for preventing lateral flow according to claim 1, wherein a buttress for reinforcing the upright wall is provided on an inner corner formed by the upright wall and the heel plate.