JP6445892B2 - Method for constructing subsidence structure and subsidence structure - Google Patents

Description

  The present invention relates to a construction method and a construction structure for a construction structure constructed by substituting a tubular construction body in the ground.

In order to construct a subsidence structure such as a shaft or pier reinforcement in the ground, a subsidence method is known in which a subsidence body in which a plurality of ring bodies are overlapped and connected in the axial direction is submerged in the ground.
When sinking a submerged object in the ground, provide a cutting edge ring on the ground surface of the construction site, excavate the ground inside the cutting edge ring, and then turn the top edge of the cutting edge ring toward the ground using a sinking device. Press and sink the blade ring into the ground. After sinking the blade ring to a certain depth, another ring body is connected to the upper end of the blade ring, the inside of the ring body is excavated, and the upper end of the ring body is pressed toward the ground by the sinking device, The ring body is set in the ground. In this way, by repeating the assembly of the sinking body by connecting a plurality of ring bodies, the excavation of the ground, and the pressing of the sinking body in order, the sinking body can be set in the ground (for example, see Patent Document 1). ).

Japanese Patent No. 3967494

In recent years, construction of subsidence structures with large cross sections and depths has increased, but the conventional method of connecting ring bodies, excavating the ground, and pressing the subsidized structures in order, requires construction of large cross sections and large depths. As it becomes, the time required for each process increases and the construction period becomes longer.
In order to solve this problem, a method of excavating the ground while connecting the ring bodies may be considered. However, when carrying out excavated earth and sand out of the ring body, the bucket of a heavy machine etc. passes above the operator who is connecting the ring body, making it difficult to ensure safety.
Therefore, it has been desired to shorten the construction period while ensuring safety even in construction with a large cross section and a large depth.

  Therefore, the present invention has been made in view of the above problems, and a construction method and a construction of a submerged structure capable of shortening a construction period while ensuring safety even in construction with a large cross section and a large depth. The object is to provide a structure.

  In order to solve the above problems, the present invention includes a step of assembling a first sinking body by overlapping and connecting the first ring bodies in the axial direction thereof, and after connecting the first ring bodies, Excavating the ground inside the sinking body and applying force from above the first sinking body to sink the first sinking body into the ground, and assembling and setting the first sinking body After completion, assembling the second sinking body so as to surround the first sinking body by overlapping and connecting the second ring body having a diameter larger than that of the first ring body in the axial direction; and While assembling the second sinking body, the ground inside the second sinking body is excavated, and the excavated soil is put inside the first sinking body, and a force is applied from above the second sinking body. And the step of sinking the second sinking body into the ground and the inside of the first sinking body A step of removing the said the Kezudo first sinking body, and having a.

  In addition, after the assembly of the second subsidence body and the completion of the subsidence, the groundwater inside the second subsidence body is drained, and after the drainage of the groundwater is completed, the excavated soil that has been poured into the first subsidence body And the first sinking body are preferably removed.

  In parallel with the assembly of the second sinking body, it is preferable that the excavated soil and groundwater put inside the first sinking body are discharged and only the groundwater is returned to the first sinking body.

  A step of excavating the ground below the first sinking body through a through-hole penetrating along the axial direction of the first ring body; and taking a reaction force on the excavated ground, A step of installing a first anti-lifting anchor that is locked to the sinking body to prevent the first sinking body from being lifted; and a first through the through-hole penetrating along the axial direction of the second ring body. A step of excavating the ground below the subsidence body 2 and a second levitation that takes a reaction force on the excavated ground and engages with the second subsidence body to prevent the second subsidence body from rising And a step of installing a prevention anchor.

  Moreover, it is preferable that each levitation prevention anchor is latched in the through-hole of each sinking body.

  A step of constructing a concrete layer on the inner bottom of the first sinking body after assembling the second sinking body after completing the setting of the first sinking body; It is preferable to have a step of constructing a concrete layer at the bottom inside the second sedimentation body outside the first sedimentation body before draining the groundwater after completion of the sedimentation.

  Moreover, it has the process of constructing | assembling a 2nd concrete layer on the upper surface of the constructed said concrete layer, after removing the excavated soil thrown into the inside of the said 1st sedimentary body, and the said 1st sedimentary body. Is preferred.

  Moreover, it is preferable to guide the groundwater inside the first sinking body to the outside of the first sinking body through a flow hole formed in the first ring body.

  Before assembling the first sinking body, a step of installing a first sinking anchor that takes a reaction force when sinking the first sinking body into the ground, and assembling the second sinking body It is preferable to have a step of installing a second anchoring anchor that takes a reaction force when the second sinking body is submerged in the ground.

  The present invention is a subsidence structure constructed by the construction method of the subsidence structure described above, wherein each ring body includes a plate forming a wall surface, and a main girder erected on the upper end and lower end of the plate Each main girder has a through-hole penetrating along the axial direction of each ring body.

  The levitation prevention anchor is provided in the fixing portion fixed to the ground excavated below each sinking body, the connecting portion connected to the fixing portion and inserted into the through hole, and the connecting portion. It is preferable to include a locking portion locked to each ring body.

  Moreover, it is preferable that the said latching | locking part is formed so that the area of a cross section may become larger than the opening area of the said through-hole.

  Moreover, it is preferable to have the concrete layer constructed | assembled in the bottom part inside the said sedimentation body, and to latch the said latching | locking part to each ring body within the range of the depth by which the said concrete layer is constructed | assembled.

  According to the present invention, the construction period can be shortened while ensuring safety even in construction with a large cross section and a large depth.

It is the schematic front view which looked at a part of submerged structure laid in the ground. It is a top view of a ring body. It is a perspective view of a segment. It is the schematic which shows the structure of the lower end part of a sunk anchor. It is the schematic which shows the structure of the lower end part of a levitation prevention anchor. It is the schematic which shows the structure of the bottom board part vicinity after completion of the installation of a sinking body. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure. It is a figure which shows the method of constructing a sunk structure.

  A preferred embodiment of the present invention will be described with reference to the drawings. In addition, embodiment shown below is one illustration and can take a various form in the scope of the present invention.

<Configuration of subsidence structure>
FIG. 1 is a schematic front view of a part of a submerged structure 10 submerged in the ground, showing an example in which the subsidence structure 10 is applied to a shaft. FIG. 2 is a plan view of the ring body 11. FIG. 3 is a perspective view of the segment 12.
As shown in FIG. 1, the subsidence structure 10 is provided at an excavation start point or an intermediate point of a tunnel T constructed in the ground by a shield method or the like, and a space S inside the subsidence structure 10 is a shield machine. It becomes a conveyance path and a vent.
As shown in FIG. 1, the subsidence structure 10 includes a subsidence body 1 submerged in the ground, a bottom plate part 2 provided on a bottom portion inside the subsidence body 1, and a subsidence body 1 when subsiding in the ground. And the anti-floating anchor 4 for preventing the floating of the sinking body 1.

(Sink)
As shown in FIG. 1, the sinking body 1 is constructed in a cylindrical shape, and is set in the ground so that its axis is along the vertical direction. The sinking body 1 is assembled by connecting a plurality of ring bodies 11 having an annular shape in plan view as shown in FIG. 2 in the axial direction thereof. The ring body 11A at the lowest end among the ring bodies 11 constituting the set-up body 1 is a blade edge ring 11A having a blade edge. As shown in FIG. 1, in the ring bodies 11 adjacent to each other in the upper and lower directions, the segments 12 of the upper ring body 11 and the segments 12 of the lower ring body 11 are shifted in the circumferential direction of the ring body 11 and staggered. Is arranged.
The ring body 11 is assembled by connecting segments 12 as shown in FIG. 3 along the wall surface direction.

As shown in FIG. 3, the segment 12 includes a rectangular plate 12a that is curved in an arc shape, two main girders 12b erected on the outer edge along the curve of the plate 12a, and each main girder 12b. Two joints 12c erected on the outer edge of the plate 12a so as to connect both ends, and a rib 12d provided on the inner surface side of the plate 12a in parallel with the joint 12c so as to connect between the two main girders 12b, It has. The main beam 12b, the joint 12c, and the rib 12d may all be joined to the plate 12a by welding, or a part thereof may be formed integrally with the plate 12a.
The main girder 12b is erected on the upper end portion and the lower end portion of the plate 12a when the segment 12 is used as the ring body 11. Each main girder 12b is formed with a plurality of through holes 12f through which bolts are inserted at predetermined intervals along the extending direction. Here, the through holes 12f of the two main girders 12b are formed such that the through holes 12f penetrate each other along the same axis parallel to the axis of the ring body 11, and each of the through holes 12f of the main girders 12b. They are formed so as to face each other. When connecting the ring bodies 11 to each other, the main girders 12b of the adjacent ring bodies 11 are butted together, and bolts are inserted into both through holes 12f and tightened with nuts to connect the adjacent ring bodies 11 to each other. The sinking body 1 can be constructed. Note that all the through holes 12f may be used for connecting the ring bodies 11, or some of the through holes 12f may be used as holes through which the anti-levitation anchors 4 are passed.
Each joint 12c is formed with a plurality of through holes 12g through which bolts are inserted at predetermined intervals along the extending direction. When connecting the segments 12 to each other, the joints 12c of the adjacent segments 12 are butted together, and bolts are inserted into both through holes 12g and tightened with nuts to connect the adjacent segments 12 to each other. Can be built. At this time, the plate 12 a constitutes the wall surface of the ring body 11.

(Bottom board)
As shown in FIG. 1, the bottom plate part 2 serves as a foundation for the subsidence structure 10 and prevents underground water from flowing into the subsidence body 1.
The bottom board part 2 is constructed by, for example, underwater concrete. The base 2 is a foundation concrete layer 21 that is constructed by being placed in a plurality of times, and a surface that is constructed by constructing the top surface of all the foundation concrete layers 21 at once after the foundation concrete layer 21 is constructed. And a concrete layer 22.
Each foundation concrete layer 21 is constructed so that the depth of the layer is substantially the same. The surface concrete layer 22 is constructed such that its upper surface is substantially along a horizontal plane.

(Sink anchor)
FIG. 4 is a schematic view showing the configuration of the lower end portion of the sinking anchor 3.
As shown in FIG. 1, in the step of sinking the sinking body 1, the sinking anchor 3 is applied to the ground when a force is applied to the ring body 11 from above the uppermost ring body 11 and pushed into the ground. The reaction force is taken. As shown in FIG. 4, the anchoring anchor 3 is embedded in and fixed to the ground excavated outside and below the settling position of the sinking body 1, and is connected to the fixing part 31. It has a connecting part 32 that extends to the ground surface along the wall surface and is connected to a stationary part (such as a base part) of a sinking device 90 (see FIG. 8) that pushes the ring body 11.
The fixing unit 31 is formed of, for example, a grout poured into the excavated ground. The fixing portion 31 is constructed at a position deeper than the blade ring 11 </ b> A outside the blade ring 11 </ b> A at the lowermost end of the set-up body 1.
The connection part 32 is formed with the steel wire (wire rope), for example. The lower end portion of the connecting portion 32 is embedded and fixed in the fixing portion 31 by solidification of the grout, and the upper end portion is connected and fixed to the immovable portion of the settling device 90.
The fixing portion 31 and the connecting portion 32 are formed to extend on the same axis along a direction perpendicular to the ground surface.

(Anti-floating anchor)
FIG. 5 is a schematic diagram showing the configuration of the lower end portion of the anti-floating anchor 4.
As shown in FIG. 1, the anti-lifting anchor 4 prevents the sinking body 1 from rising after the sinking body 1 is set. As shown in FIG. 5, the levitation prevention anchor 4 is connected to the fixing unit 41, embedded in and fixed to the ground excavated below the ring body 11 constituting the sinking body 1, and the ring body 11. A connecting portion 42 that is inserted into the through-holes 12f of the segment 12 that constitutes and extends through all the ring bodies 11 to the ground surface, and is connected to a structure or ground near the ground surface, and is provided in the connecting portion 42. And a locking portion 43 that is locked to the segment 12 of the ring body 11.
The fixing unit 41 is formed by, for example, a grout poured into the excavated ground. The fixing unit 41 is constructed at a position below the lowermost blade edge ring 11 </ b> A of the sinking body 1.
The connecting portion 42 is formed of, for example, a steel wire (wire rope). The lower end portion of the connecting portion 42 is embedded and fixed in the fixing portion 41 by solidifying the grout, and the upper end portion is connected and fixed to a structure or ground near the ground surface.
The locking portion 43 is provided in the middle of the connecting portion 42, has a cross-sectional area smaller than the opening area of the through hole 12f of the ring body 11, and is smaller than the opening area of the through hole 13f of the blade ring 11A. The cross section of the cross section is formed to be large. That is, when the connecting portion 42 is inserted into the through holes 12f and 13f, the locking portion 43 can pass through the through hole 12f of the ring body 11 but cannot pass through the through hole 13f of the blade ring 11A. It is configured. Thereby, when the sinking body 1 tries to float up toward the ground surface, the locking part 43 is locked in the through hole 13f of the blade ring 11A, and the sinking body 1 is prevented from being lifted. The locking portion 43 is locked to the ring body 11 within a depth range where the foundation concrete layer 21 is constructed. The locking portion 43 may be formed integrally with the connecting portion 42 or may be formed separately.

FIG. 6 is a schematic view showing a configuration in the vicinity of the bottom plate part 2 after the set-up body 1 is completely set.
As shown in FIG. 6, after the installation of the sinking anchor 3 and the anti-floating anchor 4, when the bottom board part 2 is formed, the lower part of the bottom board part 2 is in a state where the ground is supported by a plurality of fixing parts 31, 41. Since the support points increase in a continuous beam shape, the thickness of the bottom plate portion 2 can be suppressed. Moreover, since the connection parts 32 and 42 of both anchors 3 and 4 are left in the concrete layer which forms the bottom board part 2, using the connection parts 32 and 42 as a reinforcing bar which strengthens the concrete layer of the bottom board part 2 is used. it can.

<Method of constructing a submerged structure>
Next, a method of constructing the subsidence structure 10 by substituting the subsidence body 1 will be described with reference to FIGS. The construction method of the submerged structure 10 described below is a method useful for construction with a large cross section and a large depth, and after the first submerged body 5 (for example, the outer diameter is about 10 m) having a small cross section, A second sinking body 1 having a large cross section (for example, an outer diameter of about 30 m) is set to surround the first sinking body 5, and after the second sinking body 1 is set, the first sinking body 5 is removed. Is.

  First, as shown in FIG. 7, a plurality of excavation holes are formed using a rotary percussion 91 on the outside of a construction location where the sinking body 5 is constructed. The excavation hole is formed in an annular shape with a predetermined interval along the outer wall of the subsidence body 5 to be subsidized. The excavation hole is formed to a position deeper than the lower end of the sinking body 5 along a direction perpendicular to the ground surface. A grout is injected into each of the formed excavation holes, and a connecting portion (wire rope) 32 is inserted into the excavation hole. At this time, the lower end portion of the connecting portion 32 is immersed in the grout. By fixing the grout, the fixing portion 31 and the connecting portion 32 fixed to the fixing portion 31 are constructed, and installation of the sinking anchor 3 (first sinking anchor) is completed.

Next, as shown in FIG. 8, the settling device 90 is installed at a construction location where the settling body 5 is constructed, and the upper end of the connecting portion 32 is connected to a non-moving portion (a leg portion or the like) of the settling device 90. The sinking device 90 is configured by, for example, a hydraulic jack, and the ring body 51 can be set in the ground by pressing the uppermost ring body 51 toward the ground.
A blade ring 51 </ b> A disposed at the lowermost end portion of the settling body 5 is installed below the settling device 90. The ground inside the installed blade ring 51A is excavated by a clam shell 93 attached to the tip of the crawler crane 92. When excavation at a depth necessary for the installation of the blade ring 51A is completed, the excavation is stopped, and the setting device 90 By pressing the upper surface of the blade edge ring 51A toward the ground, the blade edge ring 51A is laid down. After the blade edge ring 51A is set, the ring body 51 is overlapped and connected to the upper side in the axial direction of the blade edge ring 51A. After the connection of the ring body 51, the ground inside the ring body 51 is excavated by the clam shell 93, and when the excavation of the depth necessary for the sinking of the ring body 51 is finished, the excavation is stopped and The upper surface is pressed toward the ground, and the blade ring 51A and the ring body 51 are set down. After the ring body 51 is set, another ring body 51 is overlapped and connected to the upper side in the axial direction of the ring body 51. By repeating these steps, all the ring bodies 51 necessary for constructing the set-up body 5 are connected and set, and the set-up of the set-up body 5 is completed.
In addition, when the blade ring 51A and the ring body 51 are set, a force is applied to the settling device 90 to rise due to a reaction force from the ground, but the settling anchor 3 is connected to the settling device 90. So do not float up. In addition, when the settling device 90 is removed after the settling body 5 is set, the upper end portion of the connecting portion 32 is connected and fixed to a structure or the ground near the ground surface.

  Next, as shown in FIG. 9, after the setting of the settling body 5 is completed, underwater concrete is placed on the bottom of the settling body 5 to construct the foundation concrete layer 21. Further, the drill pipe of the rotary percussion 91 is inserted into the through holes formed in the ring body 51 and the blade edge ring 51A of the settling body 5, and the ground below the blade edge ring 51A is drilled to form a plurality of excavation holes. To do. The excavation holes are formed in an annular shape with a predetermined interval along the axis of the through hole 52f of the ring body 51 to be deposited. The excavation hole is formed to a position deeper than the lower end of the sinking body 5 along a direction perpendicular to the ground surface. A grout is injected into each of the formed excavation holes, and a connecting portion (wire rope) 42 is inserted into the excavation hole. At this time, the lower end portion of the connecting portion 42 is immersed in the grout. By fixing the grout, the fixing portion 41 and the connecting portion 42 fixed to the fixing portion 41 are constructed. The upper end portion of the connecting portion 42 is connected and fixed to a structure or ground near the ground surface.

  As shown in FIG. 5, similar to the through holes 12f and 13f of the ring body 11 and the blade edge ring 11A, in the vicinity of the upper end portion of the blade edge ring 51A after the connecting portion 42 is inserted into the ring body 51 and the blade edge ring 51A. Is provided with a locking portion 43 having a cross-sectional area smaller than the opening area of the through-hole 52f of the ring body 51 and a cross-sectional area larger than the opening area of the through-hole 53f of the blade ring 51A. Yes. That is, when the connecting portion 42 is inserted into the through holes 52f and 53f, the locking portion 43 can pass through the through hole 52f of the ring body 51 but cannot pass through the through hole 53f of the blade ring 51A. It is configured. Thereby, the latching | locking part 43 is latched by the through-hole 53f of 51 A of blade edge rings. Installation of the levitation prevention anchor 4 (first levitation prevention anchor) is completed by the engagement of the engagement portion 43 with the through hole 53f.

  Next, as shown in FIG. 10, a plurality of excavation holes are formed using a rotary percussion 91 on the outside of the construction location where the sinking body 1 is constructed. The excavation hole is formed in an annular shape with a predetermined interval along the outer wall of the subsidence body 1 to be submerged. The excavation hole is formed to a position deeper than the lower end of the sinking body 1 along a direction perpendicular to the ground surface. A grout is injected into each of the formed excavation holes, and a connecting portion (wire rope) 32 is inserted into the excavation hole. At this time, the lower end portion of the connecting portion 32 is immersed in the grout. By fixing the grout, the fixing portion 31 and the connecting portion 32 fixed to the fixing portion 31 are constructed, and the installation of the settling anchor 3 (second settling anchor) is completed.

Next, as shown in FIG. 11, a settling device 90 is installed at a construction location where the settling body 1 is constructed, and the upper end of the connecting portion 32 is connected to a non-moving portion (such as a leg portion) of the settling device 90. The sinking device 90 is configured by, for example, a hydraulic jack, and the ring body 11 can be set in the ground by pressing the uppermost ring body 11 toward the ground.
Below the settling device 90, a blade edge ring 11A, which is disposed at the lowermost end of the settling body 1 and has a diameter larger than the blade edge ring 51A, is installed so as to surround the blade edge ring 51A. The ground inside the blade ring 11A that has been installed is excavated by the clam shell 93 attached to the tip of the crawler crane 92, and the excavated soil C is not carried out to the outside, but the space inside the already constructed substructure 5 In In parallel with this excavation, the sinking device 90 presses the upper surface of the blade ring 11A toward the ground, thereby setting the blade ring 11A. After the blade edge ring 11A is set, the ring body 11 having a larger diameter than the ring body 51 is overlapped and connected to the upper side in the axial direction of the blade edge ring 11A. During this time, excavation is continued, and the ring body 11 is connected and set according to the pace of excavation. Here, the excavation work and the assembly work of the ring body 11 are performed using separate crawler cranes 92, respectively. For example, four crawler cranes 92 are arranged around the set-up body 1 at equal intervals (positioned every 90 ° when viewed from the center of the set-up body 1). Excavation soil C is put into the ground excavation and sinking body 5, and the segment 12 is suspended by the other crawler crane 92 b to construct the ring body 11 and connect the ring body 11.
Thereby, all the ring bodies 11 necessary for constructing the sinking body 1 are connected and set, and the sinking of the sinking body 1 is completed.

  Next, as shown in FIG. 12, after the setting of the settling body 1 is completed, underwater concrete is placed on the bottom of the settling body 1 to construct the foundation concrete layer 21. Further, the drill pipe of the rotary percussion 91 is inserted into the through holes formed in the ring body 11 and the blade edge ring 11A of the settling body 1, and the ground below the blade edge ring 11A is drilled to form a plurality of excavation holes. To do. The excavation hole is formed in an annular shape with a predetermined interval along the axis of the through hole 12f of the ring body 11 to be deposited. The excavation hole is formed to a position deeper than the lower end of the sinking body 1 along a direction perpendicular to the ground surface. A grout is injected into each of the formed excavation holes, and a connecting portion (wire rope) 42 is inserted into the excavation hole. At this time, the lower end portion of the connecting portion 42 is immersed in the grout. By fixing the grout, the fixing portion 41 and the connecting portion 42 fixed to the fixing portion 41 are constructed. The upper end portion of the connecting portion 42 is connected and fixed to a structure or ground near the ground surface.

As shown in FIG. 5, in the vicinity of the upper end portion of the blade ring 11A after the connecting portion 42 is inserted into the ring body 11 and the blade edge ring 11A, the cross-sectional area is larger than the opening area of the through hole 12f of the ring body 11. A locking portion 43 having a small cross-sectional area and a cross-sectional area larger than the opening area of the through hole 13f of the blade ring 11A is provided. That is, when the connecting portion 42 is inserted into the through holes 12f and 13f, the locking portion 43 can pass through the through hole 12f of the ring body 11 but cannot pass through the through hole 13f of the blade ring 11A. It is configured. Thereby, the latching | locking part 43 is latched by the through-hole 13f of 11 A of blade edge rings. Installation of the levitation prevention anchor 4 (second levitation prevention anchor) is completed by the engagement of the engagement portion 43 with the through hole 13f of the blade ring 11A.
As a result, the excavated soil C is introduced only inside the settling body 5, and the groundwater is filled inside the settling body 1 and the settling body 5. In addition, a flow hole 51f that allows only water to pass through the excavated soil C without passing through the excavated soil C is formed in a segment of a part of the ring body 51 constituting the subsidence body 5. It can flow freely between the inside of the sinking body 1 on the outside. Therefore, the groundwater level is the same.

  Next, as shown in FIG. 13, a submersible pump is installed in the groundwater inside the settling body 1 and outside the settling body 5, and the groundwater is discharged to the outside of the settling body 1. Here, when the groundwater inside the settling body 1 is pumped up, the groundwater inside the settling body 5 moves to the outside of the settling body 5 through the flow holes 51f because a difference from the groundwater level inside the settling body 1 occurs. Eventually, not only the ground water inside the sinking body 1 but also the ground water inside the sinking body 5 can be pumped by the submersible pump. The excavated soil C and the groundwater introduced into the inside of the submerged body 5 are simultaneously pumped up, the excavated soil C and the groundwater are separated on the ground, and only the groundwater is returned to the submerged body 5 again to construct the submerged body 1. It may be performed simultaneously with the process, and in this case, since the excavated soil C can be carried out and the set-up body 1 can be constructed at the same time, the construction period can be further shortened.

Next, as shown in FIG. 14, the excavated soil C introduced into the settling body 5 is removed to the outside by a clamshell 93 attached to the tip of the crawler crane 92, and the ring body 51 is separated by another crawler crane 92. Is dismantled and removed to the outside. In addition, the connection part 32 of the sinking anchor 3 and the connection part 42 of the levitation prevention anchor 4 used in the construction of the sinking body 5 have substantially the same depth as the upper surface of the foundation concrete layer 21 above the locking part 43. Cut in place.
After the removal of the excavated soil C and the ring body 51 is completed, concrete is placed on the upper surface of the foundation concrete layer 21 to form the surface concrete layer 21. Thereby, the bottom board part 2 is completed.
The subsidence structure 10 is constructed through the above steps.

<Action, effect>
According to the construction method of the subsidence structure 10 as described above, when the subsidence body 1 having a large cross section (large diameter) is subsidized, the subsidence body 5 is not installed from the beginning, but the subsidence body 5 having a small diameter is provided. The subsidence body 1 has been submerged after being submerged, and the excavated soil C at the time of the subsidence body 1 is temporarily placed inside the subsidence body 5 so that the clam shell 93 that grabs the excavated soil C is a ring body. Excavation work can be continued without passing above 11.
Thereby, the ground inside the sinking body 1 can be excavated while assembling and sinking the sinking body 1 in a state in which safety is ensured without the clamshell 93 passing over the operator's head. Even in deep construction, it is not necessary to sequentially assemble the subsiding body 1, substituting it, and excavate the ground inside the subsiding body 1, thereby shortening the construction period.

Further, after the small-diameter subsidence body 5 is submerged in the ground, the large-diameter subsidence body 1 is subsidized in the ground, and the excavated soil C when the subsidence body 1 is subsidized is temporarily placed inside the subsidence body 5. Therefore, it is not necessary to secure a temporary storage space for the excavated soil C on the ground surface, and it is possible to sequentially carry out the excavating soil C carrying process which requires a relatively long work time, so that the construction period can be shortened.
Moreover, since the sinking body 5 is finally removed, the ring body 51 used for the sinking body 5 can be reused.
In addition, since some of the ring bodies 51 are formed with flow holes 51f that allow only water to pass therethrough without passing the excavated soil C, the ring bodies 51 are charged not only in the groundwater inside the settling body 1 but also inside the settling body 5. Since the groundwater contained in the excavated soil C can also be pumped up, the work efficiency when removing the excavated soil C and the subsiding body 5 is improved.

In addition, after the foundation concrete layer 21 is formed on the inner bottom of the settling body 5, the foundation concrete layer 21 is placed on the bottom outside the settling body 5 inside the settling body 1. The strength of the foundation concrete layer 21 can be exhibited earlier than the case where the underwater concrete is cast at once inside the subsiding body 1, and the strength of the bottom plate part 2 can be exhibited earlier. be able to.
Further, when the bottom board 2 is formed after the installation of the sinking anchor 3 and the anti-floating anchor 4, the lower part of the bottom board 2 is in a state of being supported by the plurality of fixing parts 31 and 41 and is supported in a continuous beam shape. Since the number of points increases, the thickness of the bottom board 2 can be suppressed. Moreover, since the connection parts 32 and 42 of both anchors 3 and 4 are left in the concrete layer which forms the bottom board part 2, using the connection parts 32 and 42 as a reinforcing bar which strengthens the concrete layer of the bottom board part 2 is used. it can.

Further, by providing the sinking anchor 3, it is possible to prevent the sinking device 90 from being lifted when the sinking bodies 1 and 5 are sinking.
Moreover, since the levitation preventing anchor 4 is inserted into the ring bodies 11 and 51, the construction area is not widened.
In addition, it is possible to prevent the sinking bodies 1 and 5 from being lifted with a simple configuration in which the locking portion 43 of the anti-lifting anchor 4 is locked to the through holes 13f and 53f of the ring bodies 11 and 51.
Moreover, since the latching | locking part 43 is latched by the ring bodies 11 and 51 within the range of the depth in which the bottom board part 2 is formed, the latching part 43 and the ring body are made of the concrete which constructs the bottom board part 2. 11 and 51 can be further strengthened.

<Others>
The present invention is not limited to the above embodiment. For example, the ring body is not limited to a circular shape in plan view, and may be formed in an elliptical shape in plan view (oval shape) or a polygonal shape in plan view.
In addition, each ring body is not limited to one formed by connecting a plurality of segments, but may be formed integrally from the beginning.
Moreover, in the anti-floating anchor, the position where the locking portion is provided is arbitrary, and can be freely changed according to the strength of the ground in order to ensure sufficient earthquake resistance. In other words, by providing the locking portion as low as possible, the axial durability of the ring body in the event of an earthquake is weakened, but the segment behavior is flexible, so that the seismic isolation performance of the subsidized body is improved.
Moreover, in the sinking body provided with a plurality of levitation prevention anchors, the position of each locking portion can be freely changed for each levitation prevention anchor. Thereby, the force which acts on the axial direction of a sedimentation body can be adjusted.

1 sinking body (second sinking body)
2 Bottom plate part 3 Sink anchor 4 Lifting prevention anchor 5 Sink body (first sink body)
10 Substituting structure 11 Ring body (second ring body)
12 segment 12f through-hole 13f through-hole 21 foundation concrete layer 22 surface concrete layer 31 fixing part 32 connecting part 41 fixing part 42 connecting part 43 locking part 51 ring body (first ring body)
51f Flow hole 52 Segment 52f Through hole 53f Through hole C Excavated soil

Claims (13)

Assembling the first sinking body by overlapping and connecting the first ring bodies in the axial direction;
After connecting the first ring body, excavating the ground inside the first sinking body and applying a force from above the first sinking body to sink the first sinking body into the ground And a process of
After the assembly of the first sinking body and the completion of the sinking, a second ring body having a diameter larger than that of the first ring body is overlapped in the axial direction so as to surround the first sinking body. Assembling the two sinking bodies;
While assembling the second sinking body, the ground inside the second sinking body is excavated, and the excavated soil is put inside the first sinking body, and a force is applied from above the second sinking body. In addition, the step of sinking the second sinking body in the ground,
Removing the excavated soil thrown inside the first sinking body and the first sinking body;
A method for constructing a submerged structure characterized by comprising:   After the assembly of the second sinking body and the completion of the sinking, the groundwater inside the second sinking body is drained, and after the drainage of the groundwater is completed, the excavated soil put inside the first sinking body and the The construction method of a subsidence structure according to claim 1, wherein the first subsidence body is removed.   In parallel with the assembly of the second sinking body, the excavated soil and groundwater put inside the first sinking body are discharged, and only the groundwater is returned to the first sinking body. Item 2. A construction method of a submerged structure according to Item 1. Excavating the ground below the first sinking body through a through-hole penetrating along the axial direction of the first ring body;
Installing a first anti-lifting anchor that takes a reaction force on the excavated ground and engages the first sinking body to prevent the first sinking body from lifting;
Excavating the ground below the second sinking body through a through-hole penetrating along the axial direction of the second ring body;
Installing a second anti-lifting anchor that takes a reaction force on the excavated ground and locks to the second sinking body to prevent the second sinking body from lifting;
The construction method of a submerged structure according to any one of claims 1 to 3, characterized by comprising:   The method for constructing a sinking structure according to claim 4, wherein each floating prevention anchor is locked in a through hole of each sinking body. Constructing a concrete layer on the inner bottom of the first sinking body after assembling the first sinking body and before assembling the second sinking body;
After draining the second sinking body, before draining the groundwater inside the second sinking body, a concrete layer is placed on the bottom inside the second sinking body outside the first sinking body. Building process;
The method for constructing a subsidence structure according to any one of claims 1 to 5, characterized by comprising:   It has the process of constructing a 2nd concrete layer on the upper surface of the constructed concrete layer, after removing excavation soil thrown into the inside of the 1st sedimentary body, and the 1st sedimentary body. The construction method of the subsidence structure according to claim 6.   The groundwater inside the first sinking body is guided to the outside of the first sinking body through a flow hole formed in the first ring body. A method for constructing a submerged structure according to claim 1. Before assembling the first sinking body, installing a first anchoring anchor that takes a reaction force when sinking the first sinking body into the ground; and
Before assembling the second sinking body, installing a second anchoring anchor that takes a reaction force when sinking the second sinking body into the ground;
The construction method of a subsidence structure according to any one of claims 1 to 8, characterized by comprising: A subsidence structure constructed by the construction method of a subsidence structure according to any one of claims 1 to 9,
Each ring body
A plate forming a wall;
A main girder erected on the upper end and lower end of the plate,
Each main girder is provided with a through-hole penetrating along the axial direction of each ring body. A subsidence structure constructed by the construction method of a subsidence structure according to claim 4 or 5,
The first anti-levitation anchor and the second anti-levitation anchor are:
A fixing portion fixed to the ground excavated below each sinking body;
A connecting portion connected to the fixing portion and inserted into the through hole;
A locking portion provided in the connecting portion and locked to each ring body;
A submerged structure characterized by comprising:   The sinking structure according to claim 11, wherein the locking portion is formed so that an area of a cross section is larger than an opening area of the through hole. Having a concrete layer built at the bottom inside the sinker,
The subsidence structure according to claim 11 or 12, wherein the locking portion is locked to each ring body within a depth range in which the concrete layer is constructed.

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