JP5681827B2 - Vertical shaft construction method - Google Patents

Description

  The present invention relates to a shaft construction method.

  Conventionally, as a technique in such a field, a ground excavation method described in Patent Document 1 below is known. In this excavation method, a retaining wall is installed along the periphery of the excavation surface of the ground, and then water is spread to a position higher than the ground surface in an area surrounded by the retaining wall. Then, the excavation surface is excavated underwater while the water level in the retaining wall is maintained.

JP 2006-219947 A

  By the way, in recent years, a method for constructing a deeper shaft has been studied. In such a deep shaft, it is required to construct a structure constituting the shaft while ensuring quality as designed. An object of this invention is to provide the shaft construction method which can construct | assemble the structure which comprises a shaft, ensuring the quality as designed.

  One aspect of the present invention is a shaft construction method for constructing a shaft, the first step of constructing a cylindrical retaining wall from the ground, and maintaining the water level inside the retaining wall at a predetermined height. A second step of excavating the region inside the retaining wall underwater to form a shaft hole with a predetermined depth and a substantially disk-shaped steel shell having a floating structure are prepared. The main body side wall is attached to the main body side wall so as to close the bottom of the main body side wall including the steel shell and the main body side wall in which the plurality of main body side wall portions are connected in the depth direction of the shaft. A fourth step of forming the main body side wall of the shaft main body wall having a bottom plate while adding the main body side wall portion on the circumferential edge of the steel shell in the atmosphere above the water surface, and the inside of the retaining wall in plan view In this area, the gap between the inner surface of the retaining wall and the outer surface of the shaft main body wall is filled. Comprising a fifth step, a sixth step of connecting the ends of ground earth retaining wall and body sidewall, the.

  In this shaft construction method, water is filled in the shaft hole inside the retaining wall, and the shaft is constructed by repeatedly adding the main body side wall onto the steel shell floating on the water surface. When the main body side wall is formed on the steel shell, the shaft main body wall sinks to a position where the buoyancy exerted by the shaft main body wall and the gravity are balanced. Furthermore, when another main body side wall part is added, the said main shaft wall will sink to the position where the buoyancy which a vertical shaft main body wall plays, and gravity balance. By repeating this step, the main body side wall of the shaft main body wall can be constructed in the water inside the retaining wall. Here, the operation of adding the main body side wall is performed in the atmosphere above the water surface. Therefore, since it becomes possible to construct a main part side wall part, confirming a construction state, quality as designed can be secured in a main part side wall of a main shaft wall which constitutes a vertical shaft. As a result, the certainty of construction in shaft construction can be improved. Further, in the sixth step, the retaining wall and the main body side wall are connected and integrated, so the total weight of the shaft is the sum of the weight of the retaining wall and the weight of the shaft main body wall. Therefore, the lifting resistance performance against the buoyancy acting on the shaft can be improved.

  The fourth step is a step of adding the main body side wall portion so that a connecting surface between the added main body side wall portion and another added main body side wall portion is located above the water surface, and concrete is applied to the steel shell body. Filling the bottom plate and filling the main body side wall with water so that the end of the main body side wall on the ground side is located near the ground. After the sixth step, the main body side wall You may further provide the 7th process of draining the water in the inside.

  According to this process, since the connecting surface between the added main body side wall and another added main body side wall is located above the water surface, the newly constructed main body side wall is entirely exposed to the atmosphere. Will be. Therefore, since it becomes possible to confirm a construction state over the whole body side wall part newly constructed | assembled, the quality as designed can be ensured more reliably in the main body side wall of a shaft main body wall. Moreover, according to this process, since the steel shell is filled with concrete, the strength of the bottom portion of the shaft main body wall is increased and it is possible to withstand high water pressure. Furthermore, according to this process, since water is poured into the main body side wall, it is possible to adjust the balance between the buoyancy and the gravity exerted by the shaft main body wall.

  The second step is the step of manufacturing the bottom slab structure forming the steel shell at a location different from the construction site of the shaft, the step of bringing the bottom slab structure into the construction site of the shaft, and the construction site of the shaft It is good also as having the process of assembling the bottom slab structure part carried in and forming a steel shell, and the process of lifting a steel shell and floating the steel shell on the water surface inside a retaining wall. According to this step, an increase in the work area necessary for preparing the steel shell can be suppressed.

  The second step is a step of constructing a dry dock adjacent to the shaft shaft and partitioned by a retaining wall, a step of assembling the steel shell in the dry dock, and assembling the steel shell Later, the process of pouring water into the dry dock, the process of removing a part of the retaining wall separating the shaft hole and the dry dock, and the steel shell from the dry dock are laterally pulled to place the steel shell inside the retaining wall. And a step of floating on the water surface. According to this process, the steel shell can be easily arranged on the water surface inside the retaining wall without using a huge lifting machine for assembling the steel shell.

  A 4th process is good also as having further the process of arrange | positioning the roller for making the shaft main body wall settle stably between the earth retaining wall and the main body side wall. According to this process, since the space | interval of a retaining wall and a main body side wall is maintained at a fixed distance, a shaft main body wall can be settled stably.

  In the fifth step, the underwater non-separable concrete may be filled between the inner surface of the retaining wall and the outer surface of the shaft main body wall. According to such a material, construction can be performed without causing material separation in water.

  The fifth step may further include a step of filling the space between the bottom plate and the bottom surface of the shaft pilot hole in a region inside the retaining wall in plan view. According to this process, the space between the bottom plate and the bottom surface of the shaft hole can be reliably filled.

  The shaft construction method is a step of filling the space between the bottom plate and the bottom surface of the shaft pilot hole in the region inside the retaining wall in plan view after the second step and before the third step. It is good also as having. According to this process, there is no need to work in a narrow space under the bottom plate, which may increase work efficiency and be advantageous in terms of quality.

  The main body side wall portion is composed of a plurality of main body side wall pieces, and the main body side wall piece is a precast material, and in the fourth step, the main body side wall portion is formed by connecting the precast material in the circumferential direction of the steel shell. It is good to do. According to the main body side wall portion combined with the precast material, the main body side wall piece, which is the precast material, can be manufactured at a place different from the construction site of the shaft. Therefore, the amount of work required for the main body side wall at the construction site of the shaft can be reduced.

  According to the shaft construction method of the present invention, a structure constituting the shaft can be constructed while ensuring quality as designed.

It is sectional drawing of the shaft constructed | assembled by the shaft construction method of this invention. It is a flowchart of the shaft construction method concerning one form of the present invention. It is sectional drawing which shows a 1st process and a 2nd process. It is sectional drawing which shows a 3rd process. It is sectional drawing which shows a 4th process. It is sectional drawing which shows the process of constructing | assembling the main body side wall in a 4th process. It is sectional drawing which shows a 4th process. It is sectional drawing which shows a 4th process and a 5th process. It is sectional drawing which shows a 6th process and a 7th process. It is a flowchart of the shaft construction method which concerns on a modification. It is sectional drawing which shows the main processes concerning a modification.

  Hereinafter, embodiments of the shaft construction method of the present invention will be described in detail. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. As shown in FIG. 1, the shaft 1 of the present embodiment is a cylindrical shaft having a large depth such as a diameter of about 35 m and a depth of about 110 m. The vertical shaft 1 has an opening on the ground 2 and is used as a vertical shaft for carrying a shield machine, for example. The interior of the shaft 1 is partitioned from the surrounding ground by a retaining wall 3, a shaft main body wall 4 and a filling portion 6. A shield machine (not shown) is carried into the bottom through the shaft 1, and a shield tunnel 5 extending in the horizontal direction from the bottom of the shaft 1 is constructed by the shield machine.

  The shaft 1 includes a substantially cylindrical retaining wall 3 extending downward from the ground 2, a shaft body wall 4 disposed inside the retaining wall 3, and a filling portion 6. The shaft main body wall 4 has a main body side wall 8 in which a plurality of main body side wall portions 7 are connected in the depth direction of the shaft 1, and a bottom plate 9 attached to the main body side wall 8 so as to close the bottom portion of the main body side wall 8. doing. The bottom plate 9 is a structure in which concrete is filled in a steel shell 11 having a floating structure and a bottom plate concrete 10 is cast. The earth retaining wall 3 and the shaft main body wall 4 are connected to each other at the end on the ground 2 side by a continuous wall coupling portion 12. Further, the filling portion 6 is formed between the bottom plate 9 and the shaft bottom surface 1 a and between the inner peripheral surface of the retaining wall 3 and the outer peripheral surface of the main body side wall 8.

  Hereinafter, a shaft construction method for constructing the shaft 1 will be described with reference to FIGS.

(First step)
As shown in FIG. 3A, in the first step S1, a retaining wall (continuous wall) 3 (see FIG. 3B) is constructed from the ground 2. Specifically, a hole 13 having a depth of about 120 m and a width of 1.5 m in a ring shape is excavated from the ground 2 by the continuous wall excavator M1, and the rebar bar 14 is suspended using the crane M2 to puncture the hole 13. Install in. Then, the concrete retaining wall 3 having a cylindrical shape is constructed by placing concrete in the hole 13.

(Second step)
Subsequently, in the second step S2, after dry excavation (not shown) to a predetermined depth, the water level filled in the retaining wall 3 is set to a predetermined height (for example, as shown in FIG. 3B). While maintaining the groundwater level 17), an inner region of the retaining wall 3 is excavated to form a shaft hole 16. The shaft hole 16 has a predetermined depth (for example, about 120 m) from the ground 2 to the shaft bottom surface 1a (see FIG. 1). In the second step S2, since the depth of the shaft pilot hole 16 is deeper than the groundwater level 17, most of the excavation process for forming the shaft pilot hole 16 is underwater excavation. In this excavation process, first, the ground is easily broken by forming a plurality of pores 18 in the ground excavated using the drill excavator M3. And the earth and sand are removed using the heavy machine M4 which has a clam shell, crushing the ground.

(Third step)
Subsequently, as shown in FIGS. 4A and 4B, in the third step S <b> 3, the steel shell body 11 is floated on the water surface 19. The steel shell 11 is a box having a substantially disk shape. First, as shown in FIG. 4A, the dry dock 21 adjacent to the shaft hole 16 is constructed, and the steel shell 11 is grounded in the dry dock 21. The dry dock 21 is a shallow hole having the same diameter as the retaining wall 3, and is partitioned from the shaft hole 16 by the retaining wall 3. After assembling the steel shell 11, water is poured into the dry dock 21, the water level of the dry dock 21 is matched with the water level of the adjacent shaft hole 16, and then the earth retaining wall 3 separating the shaft 1 and the dry dock 21. Remove the department. Then, as shown in FIG. 4B, the steel shell body 11 is laterally drawn using the crane M <b> 6, and the steel shell body 11 is floated on the water surface 19 inside the retaining wall 3. According to the third step S <b> 3, the steel shell body 11 can be easily disposed on the water surface 19 inside the retaining wall 3.

(Fourth process)
Subsequently, as shown in FIGS. 5A to 8A, the shaft main body wall 4 is constructed in the fourth step S <b> 4. In the following description, the completed shaft main body wall (see FIG. 1) will be referred to as “shaft main body wall 4”, and the unfinished shaft main body wall (see FIG. 5 (b), etc.) will be referred to as “the shaft main body wall being constructed”. 4 '"or simply" vertical body wall 4'".

(Process of constructing the main body side wall)
As shown in FIGS. 6 (a) and 6 (b), first, the main body side wall 7A is formed on the circumferential edge 11a of the steel shell 11 in the atmosphere above the water surface 19 (FIG. 6 (b)). reference). Then, since the weight of the shaft main body wall 4 ′ during construction is the sum of the weight of the steel shell 11 and the weight of the main body side wall 7 A, the shaft main body wall 4 ′ has a depth at which gravity and buoyancy are balanced. It sinks to this point. During the sedimentation, a part of the water filled in the retaining wall 3 is discharged. Here, in the settled shaft main body wall 4 ′, the connection surface 4 a between the steel shell body 11 and the main body side wall 7 </ b> A is located above the water surface 19. Subsequently, as shown in FIG. 6C, a new main body side wall portion 7B is added to the end portion 7a of the shaft main body wall 4 ′. The end portion 7a of the shaft main body wall 4 ′ is an end surface on the ground 2 side of the main body side wall portion 7A. Then, since the weight of the shaft main body wall 4 ′ is a sum of the weight of the steel shell 11 and the weight of the main body side wall portions 7A and 7B, the shaft main body wall 4 ′ has a depth to which gravity and buoyancy are balanced. Settling. Also in this case, the connecting surface 4b between the main body side wall portion 7A and the main body side wall portion 7B is positioned above the water surface 19 in the settled vertical shaft main body wall 4 ′.

(Process to arrange rollers)
The shaft main body wall 4 ′ during construction needs to be laid along the axial direction of the retaining wall 3. Then, in the 4th process S4, it has further the process of arrange | positioning the roller 22 for setting the shaft main body wall 4 'stably between the earth retaining wall 3 and the shaft main body wall 4' (FIG. 6 (c)). A gap of about 1.0 m is generated between the earth retaining wall 3 and the shaft main body wall 4 ′. Therefore, the roller 22 may be attached to the main body side wall portion 7A when the main body side wall portion 7A is formed. The rollers 22 are arranged at a predetermined interval along the depth direction of the shaft 1. According to this roller 22, since the space | interval of the retaining wall 3 and the shaft main body wall 4 'is maintained at a fixed distance, the shaft main body wall 4' can be stably settled.

(Process to fill the steel shell with concrete)
When the process of constructing the main body side wall portion 7 described above is repeatedly performed, the steel shell body 11 sequentially sinks into the shaft shaft 16. As the depth increases, the water pressure acting on the steel shell 11 increases. Therefore, as shown in FIG. 5B, when the steel shell 11 reaches a predetermined depth, the steel shell 11 is filled with concrete to increase the strength of the steel shell 11. As an example, when the steel shell 11 reaches a depth of about 50 m from the ground 2, the steel shell 11 is filled with concrete. According to this process, since the steel shell 11 is filled with concrete, the strength of the bottom of the shaft main body wall 4 ′ is increased, and it is possible to withstand high water pressure. After that, as shown in FIG. 7A, the process of constructing the main body side wall portion 7 described above is repeatedly performed to construct the main body side wall 8.

(Process for placing bottom slab concrete)
Since the main body side wall part 7 is a ring-shaped member, when the main body side wall part 7 is added to the shaft main body wall 4 ', the increase in buoyancy is greater than the increase in gravity. Therefore, it is necessary to adjust the balance between buoyancy and gravity so that the end of the main body side wall 8 on the ground 2 side is positioned in the vicinity of the ground 2 when the plurality of main body side walls 7 are added. Moreover, it is necessary to adjust the balance between the center of buoyancy and the center of gravity because of the stability of the floating body. Therefore, as shown in FIG. 7 (b), the bottom slab concrete 10 is placed on the steel shell 11 filled with concrete to increase the mass of the entire shaft main body wall 4 ', thereby reducing the amount of gravity. Make up. In the present embodiment, it is assumed that the bottom plate 9 is a structure in which the bottom plate concrete 10 is placed on the steel shell body 11 filled with concrete. Then, the process of constructing the main body side wall portion 7 described above is repeatedly performed to construct the main body side wall 8.

(Water injection process)
The phenomenon caused by the main body side wall portion 7 being a ring-shaped member proceeds every time the main body side wall portion 7 is added even after placing the bottom slab concrete 10, so the balance between buoyancy and gravity is adjusted again. There is a need. Therefore, as shown in FIG. 8A, the shortage of gravity is compensated by injecting water 24 into the shaft main body wall 4 ′ to increase the mass of the entire shaft main body wall 4 ′. Then, the process of constructing the main body side wall described above is repeatedly performed on the shaft main body wall 4 ′ filled with water to construct the main body side wall 8. According to this process, since water is injected into the main body side wall 8, the balance between the buoyancy and gravity exerted by the shaft main body wall 4 'is adjusted, and the end portion 8a of the main body side wall 8 on the ground 2 side becomes the ground surface. 2 can be controlled to be located in the vicinity of 2.
In the present embodiment, assuming that a highly permeable ground is distributed deeper than the bottom slab depth, adjustment is performed by re-watering, but impermeable ground is distributed deeper than the bottom slab depth. If it is, the buoyancy and gravity can be adjusted only by discharging the water inside the retaining wall from the clearance between the retaining wall 3 and the main body side wall 8.

(Fifth step)
Subsequently, as illustrated in FIG. 8B, in the fifth step S <b> 5, the filling portion 6 is formed. The filling portion 6 has a filling bottom portion 6a and a filling side portion 6b. The filling bottom portion 6a is formed between the bottom plate 9 and the shaft bottom surface 1a in a region inside the retaining wall 3 in plan view. The filling bottom portion 6a guides the filler supply pipe 26 connected to the concrete pump truck M7 and the mixer truck M8 on the ground 2 to the bottom plate 9 and the bottom shaft 1a through the bottom wall 9 and the bottom plate 9 to the bottom plate 9a. It is formed by filling a filler between the shaft bottom 1a and the shaft bottom (step S5a). The filling side portion 6 b is formed between the inner peripheral surface of the earth retaining wall 3 and the outer peripheral surface of the shaft main body wall 4. The filling side portion 6b guides the filler supply pipe 27 to the gap between the retaining wall 3 and the main body side wall 8, and fills the filler between the inner peripheral surface of the retaining wall 3 and the outer collecting surface of the main body side wall 8. It is formed (step S5b). For this filler, for example, underwater non-separable concrete is used.

(Sixth step)
Subsequently, as illustrated in FIG. 9A, in the sixth step S <b> 6, the continuous wall coupling portion 12 that connects the end portions of the earth retaining wall 3 and the shaft main body wall 4 is formed. First, the height of the end on the ground 2 side of the shaft main body wall 4 is matched with the height of the end on the ground 2 side of the retaining wall 3. For example, when the end of the shaft main body wall 4 is lower than the end of the retaining wall 3 (see FIG. 8B), the ground-side end of the retaining wall 3 is removed by a predetermined length. Then, in a plan view, a ring-shaped mold having a width 12a that can cover the end surfaces of the shaft main body wall 4 and the retaining wall 3 is formed, and concrete is placed in the mold. According to the sixth step S6, since the earth retaining wall 3 and the main body side wall 8 of the shaft main body wall 4 are connected and integrated, the total weight of the shaft 1 is equal to the weight of the earth retaining wall 3 and the shaft main body wall 4. The total weight. Therefore, the lifting resistance performance against the buoyancy acting on the shaft 1 can be improved.

(Seventh step)
Then, as FIG.9 (b) shows, in the 7th process S7, the water in the shaft main body wall 4 is drained. Then, a desired structure such as a ring beam 28 is constructed on the inner wall surface of the shaft main body wall 4. The shaft 1 is constructed through the above steps.

  Then, the effect by the shaft construction method of this embodiment mentioned above is demonstrated. In this shaft construction method, the shaft pilot hole 16 inside the retaining wall 3 is filled with water, and the main body side wall 7 is repeatedly added onto the steel shell body 11 floating on the water surface 19 to construct the shaft 1. When the main body side wall 7 is formed on the steel shell 11, the shaft main body wall 4 ′ sinks to a position where the buoyancy exerted by the shaft main body wall 4 ′ and gravity are balanced. Further, when another main body side wall portion 7 is added, the vertical shaft main body wall 4 ′ sinks to a position where the buoyancy exerted by the vertical shaft main body wall 4 ′ and gravity are balanced. By repeating this process, the main body side wall 8 of the shaft main body wall 4 can be constructed in the water inside the retaining wall 3. Here, the work of adding the main body side wall portion 7 is performed in the atmosphere above the water surface 19. Therefore, since it is possible to construct the main body side wall portion 7 while confirming the construction state, it is possible to ensure the quality as designed in the main body side wall 8 of the shaft main body wall 4 constituting the shaft 1. As a result, the certainty of construction in shaft construction can be improved.

  According to this process, since the connecting surface 4b between the added main body side wall portion 7 and another added main body side wall portion 7 is located above the water surface 19, the newly constructed main body side wall portion 7 is entirely Is exposed to the atmosphere. Therefore, since it becomes possible to confirm a construction state over the whole main body side wall part 7 newly constructed | assembled, the quality as designed in the main body side wall 8 of the shaft main body wall 4 can be ensured more reliably.

  Moreover, in the shaft construction method of this embodiment, the retaining wall 3 which is a water-impervious wall is constructed, and internal excavation is performed underwater. That is, since the interior of the retaining wall 3 is filled with water, the water pressure difference acting on the retaining wall 3 during excavation is almost zero, and the pressure acting on the retaining wall 3 is only earth pressure. Therefore, the wall thickness of the retaining wall 3 can be made thinner than the retaining wall when water pressure and earth pressure act. Moreover, since the interior of the retaining wall 3 is filled with water, it is possible to eliminate the need for ground improvement for stabilizing the bottom of the excavation.

  Here, when draining the water filled in the retaining wall 3, the amount of water that can be discharged to a river or the like is determined. Therefore, it is necessary to discharge the water while complying with this standard. Then, in the case where the water filled in the retaining wall 3 is discharged all at once, a case where a considerable period of time is required only by drainage may occur. On the other hand, in the shaft construction method of this embodiment, the drainage of the water filled in the retaining wall 3 is sequentially discharged when the shaft main body wall 4 ′ is constructed. More specifically, when the main body side wall portion 7 is added and the shaft main body wall 4 ′ is laid down, it is discharged from the clearance between the earth retaining wall 3 and the main body side wall 8. Therefore, since the process of discharging the water filled in the retaining wall 3 in a lump is not required, the construction period of the shaft 1 can be prevented from being prolonged.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and may be modified without changing the gist described in each claim. For example, in the embodiment, the present invention is applied to the cylindrical shaft 1, but the present invention can also be applied to shafts other than a complete cylindrical shape, such as a regular polygonal cylindrical shape and an elliptical cylindrical shape. .

  Further, for example, the second step may be a method that does not use the dry dock 21. In this case, first, the bottom slab structure part forming the steel shell 11 is manufactured at a place different from the construction site of the shaft 1. Next, the bottom plate structure part is carried into the construction site of the shaft 1, the bottom plate structure part is assembled, and the steel shell 11 is formed. Then, the steel shell 11 may be lifted and the steel shell 11 may be floated on the water surface 19 inside the retaining wall 3. In this case, an increase in work area necessary for preparing the steel shell 11 can be suppressed.

  Moreover, the main body side wall part 7 is not constructed by concrete placement, but may be constructed by connecting main body side wall pieces, which are precast materials. In this case, the ring-shaped main body side wall part 7 consists of a some arc-shaped main body side wall piece, and this main body side wall piece is a precast material. And in 4th process S4, it is good also as forming the main body side wall part 7 by connecting a precast material on the circumferential direction of the steel shell 11 on the end surface of the main body side wall part 7 constructed previously. . In this case, the main body side wall piece, which is a precast material, can be manufactured at a place different from the construction site of the shaft. Therefore, the amount of work required for forming the main body side wall 7 at the construction site of the shaft can be reduced.

  Moreover, as FIG.10 and FIG.11 shows, the filling bottom part 6a of the filling filling part 6 is made into bottom part leveling concrete, before arrangement | positioning of the steel shell 11 (after 2nd process S2, 3rd process S3). It is also possible to form (step S5a). There is no need to work in a confined space under the bottom plate 9, which may increase work efficiency and be advantageous in terms of quality. Further, when the filling bottom portion 6a is formed after the second step S2 and before the third step S3, the filling side portion 6b is placed after the fourth step S4 and before the sixth step S6. Form (step S5b).

DESCRIPTION OF SYMBOLS 1 ... Vertical shaft, 1a ... Vertical shaft bottom, 2 ... Above ground, 3 ... Earth retaining wall, 4 ... Vertical shaft main body wall, 4a ... Connection surface, 6 ... Filling filling part, 7, 7A, 7B ... Main body side wall part, 8 ... Main body side wall , 9 ... Bottom plate, 10 ... Bottom slab concrete, 11 ... Steel shell, 12 ... Connecting wall joint, 16 ... Shaft hole, 17 ... Ground water level, 19 ... Water surface, 21 ... Dry dock, 22 ... Roller, S1 ... 1 process, S2 ... 2nd process, S3 ... 3rd process, S4 ... 4th process, S5 ... 5th process, S6 ... 6th process, S7 ... 7th process.

Claims (12)

A shaft construction method for constructing a shaft,
A first step of constructing a cylindrical retaining wall from the ground;
A second step of excavating a region inside the retaining wall underwater while maintaining a water level inside the retaining wall at a predetermined height to form a shaft shaft having a predetermined depth;
Preparing a substantially disk-shaped steel shell having a floating structure, and floating the steel shell on the water surface inside the retaining wall;
A shaft main body wall having a main body side wall in which a plurality of main body side wall portions are coupled in the depth direction of the shaft, and a bottom plate that includes the steel shell and is attached to the main body side wall so as to close the bottom of the main body side wall. A fourth step of forming the main body side wall while adding the main body side wall to the circumferential edge of the steel shell in the atmosphere above the water surface;
A fifth step of filling the space between the inner surface of the retaining wall and the outer surface of the shaft main body wall in a region inside the retaining wall in plan view;
A sixth step of connecting ends of the earth retaining wall and the main body side wall on the ground , and
The fourth step includes
A first adding step of adding the main body side wall portion so that a connecting surface between the added main body side wall portion and another added main body side wall portion is located above the water surface;
After the first adding step, filling the steel shell with concrete to form the bottom plate;
After the step of forming the bottom plate, a second side wall is added to the main body side wall portion so that a connecting surface between the added main body side wall portion and another added main body side wall portion is located above the water surface. A shaft construction method comprising: a step of adding a shaft. The fourth step includes a step of pouring water into the main body side wall after the second adding step so that an end of the main body side wall on the ground side is located in the vicinity of the ground,
The shaft construction method according to claim 1, further comprising a seventh step of draining water in the side wall of the main body after the sixth step. The second step includes
A step of manufacturing the bottom slab structure part forming the steel shell at a place different from the construction site of the shaft,
Carrying the bottom slab structure into the construction site of the shaft,
Assembling the bottom slab structure carried into the construction site of the shaft and forming the steel shell; and
The shaft construction method according to claim 1, further comprising a step of lifting the steel shell and floating the steel shell on the water surface inside the retaining wall. The second step includes
A step of constructing a dry dock adjacent to the shaft hole and partitioned by the retaining wall with the shaft hole;
Assembling the steel shell in the dry dock;
After assembling the steel shell, pouring water into the dry dock;
Removing a part of the earth retaining wall that partitions the shaft shaft and the dry dock;
The shaft construction method according to claim 1, further comprising: horizontally pulling the steel shell from the dry dock and floating the steel shell on the water surface inside the retaining wall. A shaft construction method for constructing a shaft,
A first step of constructing a cylindrical retaining wall from the ground;
A second step of excavating a region inside the retaining wall underwater while maintaining a water level inside the retaining wall at a predetermined height to form a shaft shaft having a predetermined depth;
Preparing a substantially disk-shaped steel shell having a floating structure, and floating the steel shell on the water surface inside the retaining wall;
A shaft main body wall having a main body side wall in which a plurality of main body side wall portions are coupled in the depth direction of the shaft, and a bottom plate that includes the steel shell and is attached to the main body side wall so as to close the bottom of the main body side wall. A fourth step of forming the main body side wall while adding the main body side wall to the circumferential edge of the steel shell in the atmosphere above the water surface;
A fifth step of filling the space between the inner surface of the retaining wall and the outer surface of the shaft main body wall in a region inside the retaining wall in plan view;
A sixth step of connecting ends of the earth retaining wall and the main body side wall on the ground, and
The second step includes
A step of constructing a dry dock adjacent to the shaft hole and partitioned by the retaining wall with the shaft hole;
Assembling the steel shell in the dry dock;
After assembling the steel shell, pouring water into the dry dock;
Removing a part of the earth retaining wall that partitions the shaft shaft and the dry dock;
The shaft construction method comprising: horizontally pulling the steel shell from the dry dock and floating the steel shell on the water surface inside the retaining wall. The fourth step includes
A step of adding the main body side wall portion so that a connecting surface between the main body side wall portion that has been added and another main body side wall portion that has been added is positioned above the water surface;
Filling the steel shell with concrete to form the bottom plate;
Pouring water into the main body side wall so that the end of the main body side wall on the ground side is located in the vicinity of the ground, and
The shaft construction method according to claim 5, further comprising a seventh step of draining water in the main body side wall after the sixth step. The said 4th process further has the process of arrange | positioning the roller for making the said shaft main body wall settle stably between the said earth retaining wall and the said main body side wall, The any one of Claims 1-6. The shaft construction method described in 1. The shaft construction method according to any one of claims 1 to 7 , wherein in the fifth step, underwater non-separable concrete is filled between an inner surface of the retaining wall and an outer surface of the shaft main body wall. The fifth step, in the inner region of the earth retaining wall in a plan view, further comprising the step of Matsume filled between the bottom surface of the bottom plate and the vertical shaft pilot hole, any one of claims 1-8 The shaft construction method described in the item. After the second step and before the third step, a step of filling the space between the bottom plate and the bottom surface of the shaft prepared hole in a region inside the retaining wall in a plan view. The shaft construction method according to any one of claims 1 to 9 , further comprising: The main body side wall portion comprises a plurality of main body side wall pieces,
The body side wall piece is a precast material,
The shaft construction method according to any one of claims 1 to 10 , wherein in the fourth step, the main body side wall portion is formed by connecting the precast material in a circumferential direction of the steel shell body. The shaft construction method according to any one of claims 1 to 11, wherein the steel shell is a box.

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