JPH093923A - Sand boil prevention structure due to liquefaction - Google Patents

Abstract

PURPOSE: To prevent sand boil phenomenon due to liquefaction and suppress uneven settlement of an end of a building by installing a reinforced concrete floor slab of which one end is tightened and connected to the building between the end of the building built by floating foundation construction method and a boundary line of a lot. CONSTITUTION: A building 1 is constructed on loose sandy ground by floating foundation construction method, and a reinforced concrete floor slab 4 is installed between an end of the building 1 and a boundary line 2 of a lot. In this case, an end of the floor slab 4 is tightened and connected to an end of the building built by floating foundation construction method, and the floor slab 4 has enough strength and rigidity for preventing sand boil. Moreover, a beam is arranged to increase strength and rigidity furthermore, and it is made of prestressed concrete by the use of PC steel wires. The reinforced concrete floor slab 4 is provided on the ground, and a hanging wall 5 is arranged at an end of the boundary line 2 side of the lot. Furthermore, a groove 6 on a water drain side is supported by the hanging wall 5 when it is installed. Consequently, it is possible to expect further effect owing to the prevention of sand boil-phenomenon including the improvement of the ground 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand-sand prevention structure by liquefaction, which mainly prevents sand-sand from occurring due to a liquefaction phenomenon caused by an earthquake when a building is constructed by a floating foundation method in sandy soil type ground. It is a thing.

[0002]

2. Description of the Related Art When building a building on loose sandy ground,
When clear liquefaction is expected, it is common to adopt foundation piles or to carry out liquefaction prevention construction such as ground improvement even for direct foundations without piles.

However, in the case of a building having a large floor area but a small number of floors, by adopting a floating foundation construction method in consideration of the amount of earth and sand discharged and the weight of the building in terms of cost and construction period,
In many cases, complete liquefaction prevention construction is not performed. that is,
This is because it is considered that the floating foundation method with a large floor area is less likely to suffer from building subsidence and uneven subsidence due to liquefaction.

[0004]

FIG. 3 shows the construction of the building 1 by the floating foundation method as described above. From the relationship between the building width B and the liquefied layer H when the sand-sand phenomenon due to liquefaction is applied. When the building width B is sufficiently larger than the liquefaction layer H, sand liquefaction is less likely to occur under the building because it is restrained by the building.

On the other hand, at the end of the building, a sand blast phenomenon easily occurs, which causes the ground at the end of the building to sink and the building to sink. Considering the aspect of uneven settlement, it is rather possible that the settlement will concentrate on the edge of the building. In the figure, 3 indicates the expected settlement of the ground, and 2 indicates the site boundary line.

The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional examples, prevent sand blasting phenomenon due to liquefaction on the premises, and reduce unequal settlement of building edges. It is to provide a sand protection structure.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention has one end between the edge of the building and the site boundary line in the case of constructing a building by a floating foundation method on loose sandy ground. Reinforced concrete floor slabs that are tied to the building, and reinforced concrete floor slabs are provided with hanging walls at the edge of the site boundary line.In addition, reinforced concrete floor slabs are The gist is to support the drainage gutters at the side edges, and to make ground improvement between the edge of the building and the site boundary line.

[0008]

According to the first aspect of the present invention, if the floor slab made of reinforced concrete has strength and rigidity for preventing sand blowing, the sand blowing phenomenon on the site can be prevented. Moreover, even if a sand-blowing phenomenon occurs outside the site, the effect of ground subsidence is unlikely to reach the building.

According to the second aspect of the present invention, in addition to the above action, in the floor slab made of reinforced concrete, the hanging wall provided on the site boundary line side makes the sand sand phenomenon less likely to occur.

According to the present invention as set forth in claim 3, there is a risk that an independent drainage side groove will be exposed, but the drainage side groove is stabilized by being supported by the hanging wall.

According to the fourth aspect of the present invention, further improvement of the ground can be expected to further prevent the sand-blowing phenomenon.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a first embodiment of a structure for preventing sand from being liquefied according to the present invention, in which the same components as those in FIG. 3 showing the conventional example are designated by the same reference numerals.

That is, this is a case where the construction of the building 1 by the floating foundation method is constructed on loose sandy ground, and the floor slab made of reinforced concrete is provided between the end of the building 1 by the floating foundation method and the site boundary line 2. 4 is provided.

This reinforced concrete floor slab 4 has one end floating and tightly connected to the end of the building 1 by the basic construction method.
It should have sufficient strength and rigidity to prevent sand sand.

Although not shown, a beam may be provided to further increase the strength and rigidity, or a prestressed concrete structure made of PC steel wire may be used.

In this embodiment, the floor slab 4 made of reinforced concrete is provided on the ground, and the hanging wall 5 is provided at the end on the site boundary line 2 side.
When the drainage side groove 6 is provided, the hanging wall 5 supports the drainage side groove 6.

Further, between the end of the building 1 and the site boundary line 2 by the floating foundation method is below the floor slab 4 made of reinforced concrete, but ground improvement 7 may be applied to this. As the ground improvement 7 in this case, it is preferable to use vibration compaction, mechanical stirring, or the like.

By arranging the floor slab 4 made of reinforced concrete in this way, it is possible to prevent sand blast phenomenon due to liquefaction on the site and reduce uneven settlement at the end of the building. By providing the hanging wall 5, it becomes more effective.

When the ground improvement 7 is applied, a further effect can be expected by preventing the sand blowing phenomenon.

As a second embodiment of the invention, as shown in FIG. 2, a floor slab 4 made of reinforced concrete is provided in the ground, a side wall 8 is erected at the end of the site boundary line 2 side, and a drain gutter 6 is further provided. When provided, it may be supported by the side wall 8.

In this case, a buried soil 9 is applied on the floor slab 4 made of reinforced concrete.

[0022]

As described above, the liquefaction sand protection structure of the present invention prevents landscaping phenomenon due to liquefaction on the premises when a building is constructed on the loose sandy ground by the foundation construction method. In addition, it is possible to reduce uneven settlement at the end of the building.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first embodiment of a sand-sand protection structure by liquefaction of the present invention.

FIG. 2 is an explanatory view showing a second embodiment of the structure for preventing sand blow by liquefaction of the present invention.

FIG. 3 is an explanatory diagram showing construction of a building by a floating foundation method.

[Explanation of symbols]

1 ... Building by floating foundation method 2 ... Site boundary line 3 ... Expected settlement 4 ... Floor slab made of reinforced concrete 5 ... Hanging wall 6 ... Drain gutter 7 ... Ground improvement 8 ... Side wall 9 ... Buried soil

Claims (4)

[Claims] 1. When constructing a building by floating foundation method on loose sandy ground, a reinforced concrete floor slab with one end fastened to the building is provided between the end of this building and the site boundary. Characteristic liquefaction prevention structure for sand sand. 2. The sand blast prevention structure by liquefaction according to claim 1, wherein the floor slab made of reinforced concrete is provided with a hanging wall at an end on the site boundary line side. 3. The sand blast prevention structure by liquefaction according to claim 2, wherein the floor slab made of reinforced concrete supports the drainage gutter at the end on the site boundary line side. 4. The sand blast prevention structure by liquefaction according to any one of claims 1 to 3, wherein ground improvement is performed between an edge of the building and a site boundary line.