JP7356362B2 - underground wall - Google Patents

Description

The present invention relates to underground walls, and more particularly to the structure of underground walls.

For temporary underground walls such as retaining walls made of soil cement with a core material buried in it, the core material has a relatively high vertical support capacity so that it can be used as a foundation structure. It is proposed that

Conventionally, in order to increase the vertical bearing capacity of piles, it has been proposed to use foot protection piles, and it is conceivable to apply this to the core material of underground walls. A foot protection pile consists of solidified soil cement that fills a hole with an expanded bottom formed in the ground, a hollow ready-made pile built into the hole and located above the expanded bottom, and the tip of the ready-made pile. It consists of a cylindrical reinforcing cage extending downward from the inside to the widened part outside.

According to this foot protection pile, a portion of the soil cement directly under the ready-made pile that fills the expanded bottom of the hole is reinforced by the reinforcing cage, which contributes to improving the vertical bearing capacity of the ready-made pile. However, the effect of reinforcement is difficult to reach other surrounding soil cement parts other than the part of soil cement directly under the prefabricated pile at the bottom enlarged part of the hole. For this reason, there is a concern that damage such as cracks may occur in other surrounding soil cement parts during an earthquake, for example. In addition, the part (upper part) of the reinforcing bar basket that occupies the tip of the prefabricated pile may impede the ability of soil cement to fill the tip of the prefabricated pile, and this may become a factor that prevents the improvement of the vertical bearing capacity of the prefabricated pile. be.

Japanese Unexamined Patent Publication No. 6-158654

In view of the above-mentioned conventional circumstances, the present invention provides a new underground wall structure that increases the vertical support capacity of a core material buried in soil cement or concrete that fills the inside of a trench formed underground.

The underground wall according to the present invention (first invention) is made of a mixture of excavated earth and sand in the ground and cement milk that fills a groove formed by excavating the ground and consisting of a plurality of interconnected holes. Soil cement in which milk has solidified or concrete which has filled the groove and is in a solidified condition, and shaped steel or prefabricated steel which are spaced apart from each other in the direction of extension within the groove and are located above the bottom of the groove. a plurality of core materials consisting of piles, a plurality of reinforcing bar cages arranged on the bottom of the groove and extending under the lateral regions of the plurality of core materials in the extending direction of the groove, the plurality of reinforcing bar cages or the plurality of reinforcing bar cages; Two other reinforcing bar cages are included that extend in the extending direction of the groove between both the reinforcing bar cage and the plurality of core members .

According to the first invention, a part of the soil cement or concrete located under the area on both sides of each core material is a part reinforced by the reinforcing cage (reinforced part), and a part directly below each core material Another part of the soil cement or concrete located at the reinforcement part can be a restrained part restrained by the reinforcement part. By forming the reinforcing portion and the constrained portion, it is possible to improve the vertical supporting force of each core material. Furthermore, it is possible to prevent cracks from occurring in the reinforced portion and the restrained portion during an earthquake. Furthermore, the underground wall includes two other reinforcing bar cages extending in the extension direction of the groove between both the plurality of core materials and the plurality of reinforcing bar cages, so that in the periphery surrounding the plurality of core materials, By reinforcing the soil cement or concrete, the vertical supporting capacity of each core material can be further improved.

In order to prevent the occurrence of cracks, it is desirable that the length of each of the two reinforcing bar cages located at both ends of the groove in the extending direction be two to three times the diameter of the hole.

Moreover, the underground wall according to the present invention (second invention) includes the same soil cement or concrete as in the first invention, and a plurality of core materials. The underground wall further includes a rebar cage disposed on the bottom of the trench and extending below the plurality of core members in the direction of extension of the trench. Both ends of the one reinforcing bar cage reach below the side regions of two core members located at both ends of the groove in the extending direction. The underground wall further includes two other reinforcing bar cages extending in the direction of extension of the trench between the reinforcing bar cages.

According to the second invention, a part of the soil cement or concrete located under both side areas of each core material and a part of the soil cement or concrete located directly below each core material are The reinforcement section can be reinforced with two reinforcing cages. By forming the reinforcing portions, it is possible to improve the vertical supporting force of each core material. Furthermore, it is possible to prevent cracks from occurring in the reinforced portion during an earthquake. The underground wall according to the second invention further includes two other reinforcing bar cages that extend in the extending direction of the groove between both the plurality of core materials and the plurality of reinforcing bar cages. By reinforcing the soil cement or concrete around the core material, the vertical supporting capacity of each core material can be further improved.

In the second invention, it is desirable that the lengths of both ends of the one reinforcing cage be two to three times the diameter of the hole in order to prevent the occurrence of cracks.

Moreover, the underground wall according to the present invention (third invention) includes soil cement or concrete similar to that in the first embodiment, and a plurality of core materials. The underground wall according to the present invention further includes a plurality of cylindrical reinforcing bar cages arranged on the bottom of the trench, each cylindrical reinforcing bar cage extending from the bottom to the periphery of a part of each core material. Contains multiple cylindrical reinforcing cages.

According to the third invention, each cylindrical reinforcing cage allows the soil cement or concrete to be applied to a part of both side areas of each core material and under the both side areas, as well as directly below each core material. Can be reinforced. By this reinforcement, it is possible to improve the vertical supporting force of each core material. Furthermore, it is possible to prevent cracks from occurring in the soil cement or concrete under the regions on both sides of the core material during an earthquake.

The underground wall according to the third invention further includes another cylindrical reinforcing bar cage arranged on the bottom of the groove and located between two reinforcing bar cages adjacent to each other in the extending direction of the groove. be able to. According to this, it is possible to reinforce the soil cement or concrete between the side regions of both core materials.

Further, in any of the underground walls according to the first to third inventions, unlike the conventional root protection pile, a part of the reinforcing bar cage is disposed within the hollow ready-made pile, and accordingly, It is possible to avoid poor filling properties of the soil cement or concrete in the lower end of the ready-made pile, which may occur due to the above-mentioned method.

FIG. 2 is a plan view of an underground wall including an example reinforcing cage. FIG. 2 is a plan view of an underground wall having a relatively large thickness. 2 is a cross-sectional view of the underground wall taken along line 3-3 of FIG. 1; FIG. It is a sectional view of an underground wall including a reinforcing cage of another example. It is a sectional view of an underground wall including a reinforcing cage of still another example. FIG. 2 is a plan view of an underground wall including a cylindrical reinforcing cage. FIG. 2 is a cross-sectional view of an underground wall including a cylindrical reinforcing cage.

Referring to FIGS. 1-3, an underground wall is generally designated by the numeral 10.

The underground wall 10 is made of a mixture of excavated earth and sand in the ground 12 and cement milk that is supplied into a groove 14 formed in the ground 12 and fills the groove, and is made of soil cement 16 (FIG. 3) in which the cement milk is solidified. ), a plurality (three in the figure) of core members 18 made of section steel, and a plurality (four in the figure) of reinforcing bar cages 22, 24 arranged on the bottom 20 (Figure 3) of the groove 14. . The quantities of the core material 18 and the reinforcing bar cages 22, 24 can be determined arbitrarily. The illustrated rebar cages 22, 24 have a rectangular cross-sectional shape.

The groove 14 is formed by excavating the ground 12 and consists of a plurality of holes 26 that are connected to each other, and extends linearly. Here, the trench 14 shown in FIG. 1 consists of seven holes 26 arranged horizontally in the figure, and the underground wall 10 has a relatively thin thickness. Further, the groove 14 shown in FIG. 2 consists of 35 holes 26 arranged in five horizontal rows in the figure, and the number of holes 26 in each row is seven. The underground wall 10 shown in FIG. 2 has a smaller thickness than the underground wall 10 shown in FIG. The number of holes 26 and therefore the length and thickness of the underground wall 10 can be determined arbitrarily.

Instead of the soil cement, it is possible to use concrete that is supplied into the groove 14, fills the groove, and solidifies. Both the cement milk in the soil cement and the concrete solidify over time. In addition, in FIG. 3, in order to avoid complication of the figure, the drawing of the point (*) indicating the soil cement 16 covering the core material 18 and the reinforcing bar cages 22, 24 is omitted.

The illustrated steel section, which is the core material 18, is made of H section steel. The core material 18 may be made of a ready-made pile such as a steel pipe or a concrete pipe instead of the shaped steel.

The three core members 18 are located above the bottom 20 of the groove 14. More specifically, it is located at a height spaced above the bottom 20 and extends vertically through the soil cement 16. In the example shown in FIG. 1, three core members 18 are installed in three consecutive holes 26 located in the center of the row. In the example shown in FIG. 3, three core members 18 are installed in three consecutive holes 26 located at the center of the third row. Instead of the illustrated example, for example, as shown in FIG. 6, the plurality of core members 18 may be installed in every other or two or more holes 26.

Four rebar cages 22, 24 are arranged on the bottom 20 of the groove 14 and extend in the direction of extension of the groove 14 below the four lateral areas 28, 30, 32, 34 of the three cores 18, respectively. In the illustrated example, the four rebar cages 22, 24 have relatively large height dimensions, below the four lateral regions 28, 30, 32, 34 and within the four lateral regions 28, 30, 32, 34. It extends in the direction of extension of the groove 14 on both sides.

Furthermore, in the illustrated example, the regions 28 and 30 on both sides of the middle core material 18 (which is designated by the reference numeral 18a for convenience) out of the three core materials 18 are different from those of the two adjacent core materials on both sides. The two lateral regions 32 and 34 are common to both sides of the two adjacent core materials 18b and 18c, respectively. It forms the other side of the area.

The four rebar cages 22, 24 reinforce the portions 36, 38, 40, 42 (FIG. 3) of the soil cement 16 located below the lateral areas 28, 30, 32, 34 of the three cores 18, respectively. do. Also, due to the reinforced portions (reinforced portions) 36, 38, 40, and 42, the three soil cement portions 44, 46, and 50 located directly below the three core members 18 are aligned with the axis of the groove 14. Constrained in direction. More specifically, both reinforcing portions 36 and 38 constrain a portion 44 between them, both reinforcing portions 36 and 40 constrain a portion 46 between these portions, and both reinforcing portions 38 and 42 constrain a portion 44 between them. A portion 50 between these is restrained. By forming the reinforcing parts 36, 38, 40, 42 and the restrained parts 44, 46, 50, which are the restrained parts, the vertical supporting force of the three core members 18 is improved, and these parts This prevents cracks from forming during earthquakes. In the illustrated example, the soil cement 16 is further reinforced by four reinforcing bars 22, 24 in a portion of each of the lateral regions 28, 30, 32, 34 of the three cores 18.

Preferably, the length dimensions of the two reinforcing bar cages 24 located at both ends of the groove 14 in the extending direction are each set to be two to three times the diameter of the hole 26. This makes it possible to further improve prevention of the occurrence of cracks, and also prevents the soil cement 16 from being applied at the bottom of the hole 26 where the core material 18 is not installed and, in the illustrated example, at the upper part thereof. Can be reinforced.

The underground wall 10 having a relatively large thickness as shown in FIG. It is desirable that reinforcing cages 52 and 54 be included. In the illustrated example, both reinforcing bar cages 52 and 54 have the same height dimension as the two reinforcing bar cages 24, are formed integrally with the two reinforcing bar cages 24, and are connected to the two reinforcing bar cages 24. . Both reinforcing bar cages 52 and 54 are respectively arranged in the upper two horizontal rows of holes 26 and the lower horizontal two rows of holes 26 in the figure, and serve to reinforce the soil cement 16 in these holes 26. to do.

The four rebar cages 22, 24, which have smaller height dimensions than in the illustrated example, can be placed below the lateral areas 28-32 of the three cores 18. At this time, the other two reinforcing bar cages 52 and 54 are also set to have small height dimensions, and the four reinforcing bar cages 22 and 24 are placed between them.

Further, as shown in FIGS. 4 and 5, instead of the four reinforcing bar cages 22 and 24 having small height dimensions, one reinforcing bar cage 56 having a similar height dimension may be used.

The reinforcing bar cage 56 is disposed on the bottom 20 of the groove 14 and extends below the three core members 18 in the direction in which the groove 14 extends. The reinforcing bar cage 56 has both ends 56a and 56b that extend below the side regions 32 and 34 (see FIGS. 1 and 2) of the two core members 18b and 18c located at both ends in the extending direction of the groove 14, respectively. In the example shown in FIG. 5, the reinforcing bar cage 56 is placed on the bottom 20 of the groove 14 via a plurality of pairs (seven pairs in the illustrated example) of legs 57 made of reinforcing bars.

Both ends 56a and 56b of one reinforcing bar cage 56 can each have a length that is two to three times the diameter of the hole 26, as in the above example. Further, as in the above example, two other reinforcing bar cages (not shown) extending in the direction of extension of the groove 14 may be included between one reinforcing bar cage 56.

Next, referring to FIGS. 6 and 7, an underground wall 10 is shown that includes a plurality of cylindrical (cylindrical in the illustrated example) reinforcing bar cages 58. The groove 14 consists of a plurality of (seven in the illustrated example) holes 26 arranged in a horizontal row, and four core members 18 are installed in every other four holes 26. The illustrated cylindrical rebar cage 58 has an outer diameter that is slightly smaller than the diameter of the hole 26.

Four rebar cages 58 are placed on the bottom 20 of the groove 14. Each rebar cage 58 extends upwardly from the bottom 20 of the groove 14 to around a portion of each core 18 and surrounds a portion of each core 18 . The height dimension of the reinforcing bar cage 58 can be determined arbitrarily. As an example, the reinforcing bar cage 58 located at the left end in the figure has a relatively small height dimension, and surrounds the core material 18 near the lower end of the portion of the core material 18. Further, the other three reinforcing bar cages 58 have relatively large height dimensions and surround the lower portions of the three core members 18 that extend upward from the lower ends of the core members 18 .

According to this underground wall 10, the soil cement 16 is applied to a part of both side areas 60 of each core material 18, that is, both side areas near the lower end of the core material 18, or Reinforcement is provided in both side regions 60 of the lower portion of the core material 18 and below these both side regions 60, and in addition to these, directly below each core material 18. By this reinforcement, the vertical supporting force of each core material 18 can be improved. Furthermore, cracks in the soil cement 16 below both side regions 60 of the core material 18 can be prevented from occurring during an earthquake.

Further, another cylindrical (cylindrical in the illustrated example) located between two reinforcing bar cages 58 disposed on the bottom portion 20 of the groove 14 and adjacent to each other in the extending direction of the groove 14, and located within the hole 26 in the illustrated example. The reinforcing bar cage 62 may be included. In the illustrated example, rebar cage 62 has the same height and outer diameter as rebar cage 58 and is disposed within one hole 26 and extends therein from the bottom of groove 14 upwardly. According to this, it is possible to reinforce the soil cement 16 between the side regions 60 of both core materials 18, in the illustrated example, within the one hole 26.

10 Underground wall 12 Soil 14 Groove 16 Soil cement 18 Core material 20 Base of underground wall 22, 24, 56, 58 Rebar cage 26 Holes 28, 30, 32, 34, 60 Lateral areas of core material 52, 54, 62 Other reinforcing bars

Claims (4)

A mixture of cement milk that fills a groove consisting of a plurality of interconnected holes formed by excavating the ground and excavated soil of the ground, and the cement milk is solidified with soil cement, or soil cement that fills the groove and solidifies. Concrete in condition and
a plurality of core members made of shaped steel or prefabricated piles arranged in the groove at intervals from each other in the direction of its extension and located above the bottom of the groove;
a plurality of reinforcing bar cages arranged on the bottom of the groove and each extending in the direction of extension of the groove below the lateral regions of the plurality of core members;
An underground wall comprising the plurality of reinforcing bar cages or two other reinforcing bar cages extending in the direction of extension of the groove between the plurality of reinforcing bar cages and both of the plurality of reinforcing bar cages and the plurality of core materials. The underground wall according to claim 1, wherein the two reinforcing bar cages located at both ends of the groove in the extending direction each have a length that is two to three times the diameter of the hole. A mixture of cement milk that fills a trench consisting of a plurality of interconnected holes formed by excavating the ground and excavated earth and sand in the ground, and the cement milk is solidified with soil cement, or soil cement that fills the trench and solidifies. Concrete in condition and
a plurality of core members made of shaped steel or prefabricated piles arranged in the groove at intervals from each other in the direction of its extension and located above the bottom of the groove;
One reinforcing bar cage arranged on the bottom of the groove and extending below the plurality of core members in the extending direction of the groove, the opposite ends of which are on the sides of two core members located at both ends in the extending direction of the groove. one reinforcing bar cage extending under each area,
An underground wall comprising two other reinforcing bar cages extending in the direction of extension of the trench with the reinforcing bar cage between them. The underground wall according to claim 3, wherein both ends of the one reinforcing bar cage each have a length that is two to three times the diameter of the hole.

Images