JP7436182B2 - Underground structure design method, underground structure construction method, and underground structure - Google Patents

Description

The present invention relates to a method for designing an underground structure, a method for constructing an underground structure, and an underground structure.

Generally speaking, deep foundations are constructed by repeating the procedure of sequentially connecting the left and right and top and bottom edges of liner plates while excavating the ground until a specified depth is reached, constructing an earth retaining wall inside the shaft, and installing reinforcing bars inside the earth retaining wall. It is constructed by erecting the concrete and pouring concrete. An example of a prior art related to such a deep foundation is described in Patent Document 1.

In the technique described in Patent Document 1, a space holder is fixed to a liner plate, a hoop muscle is placed on a bracket that is attached to the space holder via a guide bar, and the intersection of the bracket and the hoop muscle is tied with a wire. Furthermore, by erecting the main reinforcing bars inside the hoop reinforcements and binding the intersections between the main reinforcing bars and the hoop reinforcements with wire, the process of erecting the reinforcing bars before placing concrete in the deep foundation is completed.

Utility model registration No. 3158383

However, the technology described in Patent Document 1 requires members such as space holders, guide bars, and brackets to erect reinforcing bars, which increases the cost of the members and also There was a problem in that the process of arranging the above-mentioned members would lengthen the construction period.

Therefore, the present invention provides an underground structure that reduces the amount of reinforcing bars or eliminates reinforcing bars in underground structures having earth retaining members, thereby reducing costs and shortening the construction period for the reinforcing process. The purpose of this invention is to provide a method for designing a structure, a method for constructing an underground structure, and an underground structure.

[1] An earth retaining member installed along the wall of a shaft formed by excavating the ground, an inner solidified material filled inside the earth retaining member, and a material filled between the earth retaining member and the wall of the shaft. A method for designing an underground structure including an outer solidified material, in which an earth retaining member is considered as a reinforcing member of a structure formed by the inner solidified material and the outer solidified material.
[2] Considering the earth retaining member and the reinforcing bars buried in the inner solidified material as reinforcing members, and reducing the amount of reinforcing bars by considering the earth retaining member as the reinforcing member, or omitting the reinforcing bars, The method for designing an underground structure according to [1].
[3] The reinforcing bars consist of main bars that extend in the depth direction of the shaft and hoop bars that extend in the circumferential direction of the shaft, and the amount of hoop bars can be reduced by considering earth retaining members as reinforcing members, or The method for designing an underground structure according to [2], in which the striations are omitted.
[4] The method for designing an underground structure according to any one of [1] to [3], wherein the main body surface of the earth retaining member has a corrugated cross section.
[5] A cylindrical earth retaining wall is constructed by arranging a plurality of earth retaining members in the depth direction and circumferential direction of the shaft and connecting them to each other, and the plurality of earth retaining members are arranged in either the depth direction or the circumferential direction. The method for designing an underground structure according to any one of [1] to [4], which is arranged in a staggered manner.
[6] An excavation process in which a shaft is formed by excavating the ground, an earth retention member installation process in which an earth retaining member is installed along the wall of the shaft, and an outer solidifying material is filled between the earth retaining member and the wall of the shaft. An underground structure that includes a filling process and an inner filling process of filling the inside of the earth retaining member with an inner solidified material, but does not include a reinforcement process of arranging reinforcing bars to be buried in the inner solidified material inside the earth retaining member. construction method.
[7] An excavation process in which a shaft is formed by excavating the ground, an earth retention member installation process in which an earth retaining member is installed along the wall of the shaft, and an outer solidifying material is filled between the earth retaining member and the wall of the shaft. A cylindrical earth retaining wall is formed by arranging a plurality of earth retaining members in the depth direction and circumferential direction of the shaft and connecting them to each other, including a filling step and an inner filling step of filling the inside of the earth retaining member with an inner solidified material. A construction method for an underground structure, wherein the earth retaining member installation step includes a step of arranging a plurality of earth retaining members in a staggered manner either in the depth direction or in the circumferential direction.
[8] It further includes a reinforcing step of arranging reinforcing bars to be buried in the inner solidified material inside the earth retaining member, and the reinforcing step includes a step of arranging main reinforcing bars extending in the depth direction, and hoop reinforcing bars extending in the circumferential direction. The method for constructing an underground structure according to [7], which does not include the step of arranging.
[9] The outer filling step includes a spraying step of spraying the first solidified material onto the wall surface of the shaft, and a pouring step of pouring the second solidified material between the earth retaining member and the first solidified material, [6 ] to [8]. The construction method for an underground structure according to any one of [8].
[10] An earth retaining member installed inside a shaft formed by excavating the ground, an outer solidified material filled between the earth retaining member and the wall of the shaft, and an inner solidified material filled inside the earth retaining member. An underground structure that includes steel but does not contain reinforcing steel embedded in the inner solidified material.
[11] An earth retaining member installed inside a shaft formed by excavating the ground, an outer solidified material filled between the earth retaining member and the wall of the shaft, and an inner solidified material filled inside the earth retaining member. A cylindrical earth retaining wall is constituted by a plurality of earth retaining members arranged in the depth direction and circumferential direction of the shaft and connected to each other, and the plurality of earth retaining members are arranged in the depth direction and circumferential direction of the shaft and are connected to each other. Underground structures arranged in a staggered manner.
[12] The underground structure according to [11], further including reinforcing bars embedded in the inner solidified material, the reinforcing bars including main bars extending in the depth direction and not including hoop bars extending in the circumferential direction.
[13] The underground structure according to any one of [10] to [12], wherein the earth retaining member has a main body surface having a corrugated cross section and a flange formed at an end of the main body surface.
[14] The underground structure according to [13], wherein the earth retaining member further includes a welded portion or a rib formed between the main body surface and the flange.
[15] The underground structure according to any one of [10] to [14], wherein the inner solidified material is filled between the internal space formed at the center and the earth retaining member.
[16] From [10], the outer solidified material includes a first solidified material sprayed onto the wall surface of the shaft, and a second solidified material poured between the first solidified material and the earth retention member. The underground structure according to any one of [15].
[17] The underground structure according to any one of [10] to [16], wherein the earth retaining member is formed of a steel material having a yield point exceeding 205 N/mm ² .

According to the above configuration, in an underground structure having earth retaining members, by reducing the amount of reinforcing bars or omitting reinforcing bars, it is possible to reduce the cost and shorten the construction period for the reinforcing process.

It is a sectional view of the deep foundation according to the first embodiment of the present invention. FIG. 3 is a sectional view of a deep foundation according to a second embodiment of the present invention. FIG. 3 is a sectional view of a deep foundation according to a third embodiment of the present invention. It is a figure which shows the example of the staggered arrangement|positioning of the earth retention member in the circumferential direction. It is a figure which shows the example of the staggered arrangement|positioning of the earth retention member in the depth direction. It is a figure which shows the example which adds a fillet weld to an earth retaining member. 7 is a sectional view taken along the line VII-VII in FIG. 6. FIG. It is a figure which shows the example of adding a rib to a retaining member. 9 is a sectional view taken along the line IX-IX in FIG. 8. FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals and redundant explanation will be omitted.

FIG. 1 is a sectional view of a deep foundation according to a first embodiment of the present invention. As illustrated, the underground structure 1 includes an earth retaining member 4 installed along a wall surface 3W of a shaft 3 formed by excavating the ground 2, and an inner solidification member filled inside the earth retaining member 4. It includes a material 5, an outer solidified material 6 filled between the earth retaining member 4 and the wall surface 3W of the shaft 3, and reinforcing bars 7 buried in the inner solidified material 5. In the illustrated example, the outer solidified material 6 is applied by spraying the first solidified material 6A onto the wall surface 3W of the shaft 3, and by pouring it between the first solidified material 6A and the earth retaining member 4. and a second solidified material 6B. The inner solidified material 5 and the outer solidified material 6 are, for example, concrete or mortar. The reinforcing bars 7 include main bars 7A extending in the depth direction of the shaft 3 and hoop bars 7B extending in the circumferential direction of the shaft 3. The underground structure 1 may further include a formwork member 8 used when pouring the second solidified material 6B as described below.

The earth retaining member 4 has a main body surface 41 and a flange 42 formed at an end of the main body surface 41. A plurality of earth retaining members 4 are arranged in the depth direction of the shaft 3 and in the circumferential direction of the shaft 3, and are connected to each other at flanges 42 using bolts or the like, thereby forming a cylindrical earth retaining wall. In the illustrated example, four stages of retaining members 4 are connected in the depth direction. The cross-sectional shape of the earth retaining wall constituted by the earth retaining member 4 may be, for example, circular, oval, rectangular, or horseshoe-shaped. As the earth retaining member 4, for example, a liner plate whose main body surface 41 has a corrugated cross section can be used, but in addition to what is called a liner plate, various members having similar functions can also be used as the earth retaining member 4. can.

In this embodiment, the inner solidified material 5 filled inside the earth retaining member 4 is fixed on the corrugated cross section of the main body surface 41 of the earth retaining member 4 and on the flange 42 arranged so as to protrude inside the earth retaining member 4. . The outer solidified material 6 filled on the outside of the earth retaining member 4 is also fixed to the corrugated cross section of the main body surface 41 of the earth retaining member 4. Furthermore, as described above, the earth retaining members 4 constitute an integral earth retaining wall by being connected to each other in the depth direction and the circumferential direction of the shaft 3. Therefore, in this embodiment, the earth retaining member 4 functions as a reinforcing member of the structure formed by the inner solidified material 5 and the outer solidified material 6 in both the depth direction and the circumferential direction.

Therefore, in this embodiment, when designing the underground structure 1, the amount of reinforcing bars 7 can be reduced by considering both the earth retaining members 4 and the reinforcing bars 7 as reinforcing members. Specifically, a design may be considered in which the earth retaining member 4 is considered as the main reinforcing member and the shortfall in the amount of steel material is compensated for with reinforcing bars 7. Therefore, the total cross-sectional area (number of arrangements x cross-sectional area) of each of the main reinforcing bars 7A and the hoop reinforcing bars 7B included in the reinforcing bars 7 is smaller than when the retaining member 4 is not considered as a reinforcing member. As a result, all the hoop reinforcements 7B may be omitted and only the main reinforcements 7A may be arranged. By reducing the amount of reinforcing bars 7, it is possible to reduce costs associated with the reinforcement process and shorten the construction period.

In order to make the earth retaining member 4 effectively function as a reinforcing member as described above, the earth retaining member 4 is made of a steel material with a yield point exceeding 205 N/mm ² , specifically, for example, SS400 material (yield point 245 N/mm ² ) or It may be formed from SM490 material (yield point: 325 N/mm ² ).

On the other hand, as described above, the outer solidified material 6 includes the first solidified material 6A applied by spraying and the second solidified material 6B applied by pouring. The first solidified material 6A is a fast-curing concrete or mortar suitable for spray construction, for example, concrete or mortar containing about 30 kg to 60 kg of a rapid setting agent per 1 m ³ of the solidified material. On the other hand, the second solidified material 6B is highly fluid concrete or mortar suitable for pouring construction. Since the second solidified material 6B is poured into the narrow space on the back side of the earth retaining member 4, it is preferable that it has enough fluidity to exhibit sufficient filling performance even in situations where it is difficult to vibrate with a vibrator. For example, the second solidified material 6B may be concrete or mortar having a slump flow value of 30 cm or more and containing 3 kg or more of a high-performance AE water reducer per 1 m ³ of the solidified material. After hardening, both the first solidifying material and the second solidifying material have a strength equivalent to or higher than that of the inner solidifying material 5 cast inside the earth retaining member 4, specifically, for example, a compressive strength of 24N/28 days after the material age. It is preferable to express mm ² or more.

In this embodiment, by spraying the first solidified material 6A of the outer solidified material 6 onto the wall surface 3W of the shaft 3 in advance, the wall surface 3W collapses during construction of the outer solidified material 6 and the earth retaining member 4 It is possible to prevent the distance between the wall surface 3W and the wall surface 3W from becoming closer than designed, or the earth retaining member 4 from coming into direct contact with the wall surface 3W. The distance between the earth retaining member 4 and the wall surface 3W can be visually confirmed from the upper end or lower end of the earth retaining member 4 or from an observation opening formed in the earth retaining member 4 before pouring the second solidified material 6B. can. Thereby, an appropriate cover thickness can be ensured between the earth retaining member 4 and the wall surface 3W by filling with the outer solidified material 6, and the earth retaining member 4 can be considered as a reinforcing member as described above.

Here, if the step of pouring the second solidified material 6B is carried out within a relatively short time after the step of spraying the first solidified material 6A, the second solidified material 6B may be sprayed after the completion of the underground structure 1. A seam is unlikely to remain between the first solidified material 6A and the second solidified material 6B. However, as described above, since the material properties of the first solidified material 6A and the second solidified material 6B are different, even if the first solidified material 6A and the second solidified material 6B are Even if the boundary with the material 6B is not clear, if samples are taken and analyzed on the wall surface 3W side of the outer solidified material 6 and on the earth retaining member 4 side, it can be determined that it is the first solidified material 6A applied by spraying. , and the second solidified material 6B formed by pouring can be identified.

Note that even if the outer solidification material 6 is not applied by a combination of spraying and pouring as described above, the earth retaining member 4 can be reinforced if an appropriate cover thickness is secured between the earth retaining member 4 and the wall surface 3W. It can be considered as a member. Therefore, the embodiments of the present invention are not limited to examples in which the outer solidified material 6 is applied by a combination of spraying and pouring.

The underground structure 1 according to this embodiment is constructed, for example, by the following steps. First, an excavation step is performed in which the ground 2 is excavated to form the shaft 3, and then a spraying step is performed in which the first solidified material is sprayed onto the wall surface 3W of the shaft 3. Since the second solidified material 6B is further poured in a later step, the sprayed thickness of the first solidified material 6A is a minimum thickness sufficient to stabilize the wall surface 3W until the second solidified material 6B is poured. It is sufficient if the thickness is at least the maximum thickness. Such a spraying thickness may be thinner than that of conventional spraying methods, and specifically may be, for example, 1 cm or more and less than 10 cm.

Next, an earth retaining member installation step of installing the earth retaining member 4 inside the shaft 3 is carried out. In this example, since the spraying process is performed before the earth retaining member installation process, the earth retaining member 4 is installed inside the first solidified material 6A that has already been sprayed. A formwork member 8 is installed at the lower end of the earth retaining member 4 located at the lower end of the earth retaining wall constructed at this point. The formwork member 8 may be provided with an opening for pouring the second solidified material 6B in the next step.

After installing the earth retaining member 4 and the formwork member 8, a pouring step is carried out in which the second solidified material 6B is poured between the earth retaining member 4 and the first solidified material 6A. The above-described excavation process, spraying process, earth retaining member installation process, and pouring process are repeated a predetermined number of times (one time is sufficient), and then an inner filling process is performed in which the inner solidified material 5 is filled inside the earth retaining member 4. By doing so, an underground structure 1 as shown in FIG. 1 is constructed.

In addition, in the above example, the outer filling process for filling the outer solidified material 6 was carried out as a spraying process and a pouring process before and after the earth retaining member installation process, but in other examples, the outer filling process for filling the outer solidified material 6 was performed after the earth retaining member installation process. The outer filling process may be performed all at once. In this case, in the spraying process, a spraying nozzle is inserted through the gap between the upper or lower side of the retaining member 4 and the wall surface 3W of the shaft 3, and the spraying process of the first solidified material 6A is carried out.

FIG. 2 is a sectional view of a deep foundation according to a second embodiment of the present invention. In this embodiment, unlike the first embodiment described above, all reinforcing bars are omitted by considering the earth retaining member 4 as a reinforcing member of the structure formed by the inner solidified material 5 and the outer solidified material 6. . That is, in the illustrated example, the underground structure 1 does not include reinforcing bars embedded in the inner solidified material 5. As a result of considering the earth retaining member 4 as a reinforcing member, if the required amount of steel is satisfied only with the earth retaining member 4, it becomes possible to design using only the earth retaining member 4 as a reinforcing member. In this case, the method for constructing the underground structure 1 does not include a reinforcing step of arranging reinforcing bars inside the earth retaining member 4.

FIG. 3 is a sectional view of a deep foundation according to a third embodiment of the present invention. In this embodiment, an internal space SP is formed at the center of the underground structure 1. In this case, the inner solidified material 5 is filled between the internal space SP and the earth retaining member 4. At the time of construction, a formwork member corresponding to the internal space SP is arranged, and the inner solidified material 5 is filled between the formwork member and the earth retaining member 4. The embodiments of the present invention thus include both cases where the underground structure 1 has a hollow structure and cases where it has a solid structure. The hollow underground structure 1 is used, for example, as a deep foundation, a vertical shaft, or a water collection well. Alternatively, earth and sand such as leftover soil from earth excavation may be poured into the internal space SP of the underground structure 1 and then used as a deep foundation. The solid underground structure 1 is used, for example, as a deep foundation. In addition, in the example shown in FIG. 3, all reinforcing bars are omitted as in the second embodiment, but as in the first embodiment, reinforcing bars 7 with a reduced amount of reinforcement are arranged. Good too.

FIG. 4 is a diagram showing an example of a staggered arrangement of earth retaining members in the circumferential direction. In the first to third embodiments described above, a plurality of earth retaining members 4 are arranged in the depth direction and circumferential direction of the shaft 3 and connected to each other, thereby forming a cylindrical earth retaining wall. In the example shown in FIG. 4, a plurality of retaining members 4A are arranged in a staggered manner in the circumferential direction of the shaft 3. In other words, the earth retaining members 4A arranged in a plurality of stages in the height direction (depth direction of the shaft 3) are arranged so that circumferential joints are alternated between adjacent stages.

When considering the earth retaining member 4 as a reinforcing member of the structure formed by the inner solidified material 5 and the outer solidified material 6 as described above, the joint between the earth retaining members 4 becomes a structural weak point. Therefore, in the example shown in FIG. 4, by arranging the earth retaining members 4A in a staggered manner in the circumferential direction, the force acting on the circumferential joints of the earth retaining members 4A is reduced between the earth retaining members 4A arranged adjacent to each other in the height direction. Due to the shear resistance between them, it is possible to flow into the main body of another earth retaining member 4A, and the joint can be reinforced. This improves the function of the earth retaining member 4A as a reinforcing member in the circumferential direction. Although not included, it is also possible to reduce the amount of hoop muscles 7B.

FIG. 5 is a diagram showing an example of a staggered arrangement of earth retaining members in the depth direction. In the example shown in FIG. 5, unlike the example shown in FIG. 4 above, the plurality of retaining members 4B are arranged in a staggered manner in the height direction (depth direction of the shaft 3). In other words, the earth retaining members 4B arranged in a plurality of rows are arranged so that the seams in the height direction alternate between adjacent rows. As a result, the force acting on the joint in the height direction of the earth retaining member 4B can be transferred to the main body of another earth retaining member 4B due to the shear resistance between the earth retaining members 4B arranged adjacent to each other in the circumferential direction. , seams can be reinforced. This improves the function of the earth retaining member 4B as a reinforcing member in the height direction, so that the amount of reinforcement of the main reinforcing bars 7A among the reinforcing bars 7 can be effectively reduced, for example, as in the illustrated example.

FIGS. 6 and 7 are diagrams showing an example of adding fillet welds to earth retaining members. In the illustrated example, the retaining member 4 has flanges 42 formed at both ends of the main body surface 41 in the height direction, as well as flanges 43 formed at both ends of the main body surface 41 in the circumferential direction. The flange 43 is arranged in a direction intersecting the corrugated cross section of the main body surface 41. In the example shown in FIGS. 6 and 7, the earth retaining member 4 further includes fillet welds 44 on both sides formed between the main body surface 41 and the flange 43. As a result, stress is effectively transmitted from the main body surface 41 to the flange 43 (preferably, the entire stress is transmitted), and the plurality of connected earth retaining members 4 can function as an integral reinforcing member in the circumferential direction. . Note that other types of welds capable of transmitting stress, such as groove welds, are not limited to the fillet welds 44 on both sides.

FIGS. 8 and 9 are diagrams showing an example of adding ribs to the earth retaining member. In the illustrated example, the earth retaining member 4 further includes a rib 45 formed between the main body surface 41 and the flange 43 in addition to the main body surface 41 and the flanges 42 and 43. This effectively transmits the stress (preferably the entire stress) from the body surface 41 to the flange 43, similar to the example described above with reference to FIGS. The earth retaining member 4 can function as an integral reinforcing member in the circumferential direction. Note that the ribs 45 are not limited to the triangular shape as in the illustrated example, but ribs having other shapes such as a trapezoid or a fan shape may be formed.

Note that, as long as stress can be sufficiently transmitted between the main body surface 41 and the flange 43, the reinforcing structure as described above does not need to be provided. Moreover, although the example in which the earth retaining member 4 has flanges 42 and 43 at the end of the main body surface 41 has been described above, for example, a corrugated pipe without flanges 42 and 43 may be used as the earth retaining member 4. In this case, there is no flange at the joint between the earth retaining members 4, and the earth retaining members 4 are connected by fixing the overlapping parts of the body surfaces 41 with bolts, etc., so the body surfaces and flanges as described above are connected. There is no need for a reinforcing structure between the two.

Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

1... Underground structure, 2... Ground, 3... Vertical shaft, 3W... Wall surface, 4, 4A, 4B... Earth retaining member, 5... Inner solidified material, 6... Outer solidified material, 6A... First solidified material, 6B... Second solidified material, 7... Rebar, 7A... Main reinforcement, 7B... Hoop reinforcement, 8... Formwork member, 41... Body surface, 42, 43... Flange, 44... Fillet weld, 45... Rib, SP... Inside space.

Claims (16)

An earth retaining member installed along the wall of a shaft formed by excavating the ground, an inner solidified material filled inside the earth retaining member, and a material filled between the earth retaining member and the wall of the shaft. In a method for designing an underground structure including an outer solidified material,
Considering the earth retaining member as a reinforcing member of the structure formed by the inner solidified material and the outer solidified material,
The retaining member includes a body surface having a corrugated cross section with no openings , and the outer solidified material is filled between the body surface and the wall surface of the shaft;
The strength of the outer solidified material is equal to or higher than the strength of the inner solidified material,
A method for designing an underground structure, wherein at least the main body surface of the earth retaining member is considered as the reinforcing member . The earth retaining member further includes a flange formed at an end of the main body surface, and a fillet weld formed on both sides of the main body surface between the main body surface and the flange. Design method for underground structures described. The earth retaining member further includes a flange formed at an end of the main body surface, and a rib formed between the main body surface and the flange, the plate surface of which intersects the main body surface and the flange. The method for designing an underground structure according to claim 1 or claim 2. The method for designing an underground structure according to claim 1, wherein the earth retaining member is a corrugated pipe. As the reinforcing member, the earth retaining member and the reinforcing bars buried in the inner solidified material are considered, and the amount of reinforcement of the reinforcing bars is reduced by considering the earth retaining member as the reinforcing member, or the reinforcing bars are The method for designing an underground structure according to any one of claims 1 to 4, wherein the method is omitted. The reinforcing bars consist of main bars extending in the depth direction of the shaft and hoop bars extending in the circumferential direction of the shaft, and the amount of reinforcement of the hoop bars is reduced by considering the earth retaining member as the reinforcing member; The method for designing an underground structure according to claim 5, wherein the hoop reinforcement is omitted. A cylindrical earth retaining wall is constructed by arranging the plurality of earth retaining members in the depth direction and circumferential direction of the shaft and connecting them to each other,
The method for designing an underground structure according to any one of claims 1 to 6, wherein the plurality of earth retaining members are arranged in a staggered manner in either the depth direction or the circumferential direction. An underground structure designed using the underground structure design method according to any one of claims 1 to 7. an excavation process in which the ground is excavated to form a shaft;
an earth retaining member installation step of installing an earth retaining member along the wall surface of the shaft;
an outer filling step of filling an outer solidified material between the earth retaining member and the wall surface of the shaft;
and an inner filling step of filling an inner solidified material inside the earth retaining member,
Does not include a reinforcing step of arranging reinforcing bars to be buried in the inner solidified material inside the earth retaining member,
The retaining member includes a body surface having a corrugated cross section with no openings , and the outer solidified material is filled between the body surface and the wall surface of the shaft;
The strength of the outer solidified material is equal to or higher than the strength of the inner solidified material,
A method of constructing an underground structure, wherein at least the main body surface of the earth retaining member is considered as a reinforcing member of a structure formed by the inner solidified material and the outer solidified material . The earth retaining member further includes a flange formed at an end of the main body surface, and a fillet weld formed on both sides of the main body surface between the main body surface and the flange. Construction method of the underground structure described. The earth retaining member further includes a flange formed at an end of the main body surface, and a rib formed between the main body surface and the flange, the plate surface of which intersects the main body surface and the flange. The method for constructing an underground structure according to claim 9 or claim 10. The method for constructing an underground structure according to claim 9, wherein the earth retaining member is a corrugated pipe. an excavation process in which the ground is excavated to form a shaft;
an earth retaining member installation step of installing an earth retaining member along the wall surface of the shaft;
an outer filling step of filling an outer solidified material between the earth retaining member and the wall surface of the shaft;
and an inner filling step of filling an inner solidified material inside the earth retaining member,
A cylindrical earth retaining wall is constructed by arranging the plurality of earth retaining members in the depth direction and circumferential direction of the shaft and connecting them to each other,
The earth retaining member installation step includes a step of arranging the plurality of earth retaining members in a staggered manner in either the depth direction or the circumferential direction,
The retaining member includes a body surface having a corrugated cross section with no openings , and the outer solidified material is filled between the body surface and the wall surface of the shaft;
The strength of the outer solidified material is equal to or higher than the strength of the inner solidified material,
A method of constructing an underground structure, wherein at least the main body surface of the earth retaining member is considered as a reinforcing member of a structure formed by the inner solidified material and the outer solidified material . Further comprising a reinforcement step of arranging reinforcing bars to be buried in the inner solidified material inside the earth retaining member,
14. The method for constructing an underground structure according to claim 13, wherein the reinforcement step includes a step of arranging main reinforcements extending in the depth direction and does not include a step of arranging hoop reinforcements extending in the circumferential direction. The outer filling step includes:
a spraying step of spraying a first solidified material onto the wall surface of the shaft;
The method for constructing an underground structure according to any one of claims 9 to 14, comprising: a pouring step of pouring a second solidified material between the earth retaining member and the first solidified material. An underground structure constructed using the method for constructing an underground structure according to any one of claims 9 to 15.

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