JP3168197B2 - Caisson anchor structure and construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caisson anchor structure which is settled on a ground set ground by a caisson method such as a pneumatic caisson method, and a method of constructing the anchor structure.

[0002]

2. Description of the Related Art A caisson as a foundation which is settled on an underground setting ground is not usually provided with anchor means for enhancing its stability. As shown in FIG. 15, the supporting ground G was used because the weight and the surrounding supporting ground were balanced.
If 1 is not homogeneous, the support is installed in a balanced state with a bias in the supporting force of the peripheral support ground. For this reason, when a large earthquake or unexpected large loosening of the set ground occurs, a situation in which the entire caisson including structures such as supporting piers is tilted sometimes occurs.

[0003]

SUMMARY OF THE INVENTION A caisson anchor structure and a method of constructing the same according to the present invention have been developed in order to prevent the occurrence of the above-mentioned situation, and have a foundation for supporting a structure such as a pier. It has been proposed for the purpose of improving the stability of a caisson, or reducing the cross-sectional area of the caisson, thereby constructing an economically advantageous caisson foundation.

[0004]

In order to achieve the above object, a caisson anchor structure according to claim 1 of the present invention is characterized in that a plurality of vertical holes drilled at appropriate intervals in a caisson setting ground. A lower anchor member is inserted into each, and the lower anchor member in each vertical hole is fixed by solidification of the grout, and a plurality of lower anchor members corresponding to the positions of the plurality of lower anchor members are mounted on the ceiling slab of the caisson work room. The upper anchor member is embedded and fixed, and the lower end of the upper anchor member and the upper end of the lower anchor member corresponding to each other are connected by connecting means, respectively, and furthermore, concrete is buried in the caisson work room. It is characterized by.

According to a second aspect of the present invention, in the caisson anchor structure of the first aspect, the connecting means includes a first connecting block attached to a lower end of an upper anchor member;
A plurality of connection bolts inserted through the first and second connection blocks for calling and connecting the second connection block attached to the upper end of the lower anchor member to the first and second connection blocks; It is characterized by comprising nuts screwed to these connection bolts.

According to a third aspect of the present invention, in the caisson anchor structure of the first aspect, the connecting means includes a first bolt having an upper end screwed to a screw coupler provided in an upper anchor member, and a first bolt thereof. A turnbuckle having an upper end screwed to the lower end of the bolt, a second bolt having an upper end screwed to the lower end of the turnbuckle, and an upper end screwed or welded to the lower end of the second bolt; And a sleeve joint fixed to the upper end of the lower anchor member by welding or crimping.

In addition, the method for constructing a caisson anchor structure according to claim 4 of the present invention is as follows: (A) A caisson is provided on a ground above a predetermined set ground of a caisson with a drilling machine at an appropriate interval. A step of drilling a plurality of vertical holes under the ground to be set, (B) a step of inserting a lower anchor member into each vertical hole and installing it at the bottom of the vertical hole, and (C) grouting each vertical hole through an injection pipe. Injecting and solidifying the lower anchor member in the vertical hole, (D) installing a reinforced concrete caisson on the ground on the ground to be set, and installing the lower anchor member on the ceiling slab of the lower working room A step of burying and fixing a plurality of upper anchor members corresponding to the position, (E) a step of excavating the lower surface of the caisson work chamber and sinking it to a predetermined position, and (F) each upper part projected or exposed into the caisson work chamber. Step of binding a connecting means lower and upper ends of each of the lower anchor member anchor member, and (G)
The method further comprises the step of casting infill concrete into a caisson work chamber and embedding the lower end of the upper anchor member and the upper end of the lower anchor member connected by the connecting means in the work chamber.

According to a fifth aspect of the present invention, in the method for constructing a caisson anchor structure according to the fourth aspect, each of the lower anchor members is configured as an aggregate of a plurality of unit anchor members, and the lower anchor member of the injection grout is provided. The contact area with respect to is increased.

Further, the invention of claim 6 is the invention of claim 4 or 5
In the construction method of the caisson anchor structure of the above, the sheath tube is fixed around each of the lower anchor members, and the tip portions of two grout injection tubes inserted into the sheath tube are connected to the lower anchor member. Attached to the member, the tip of one injection tube was opened inside the sheath tube, the tip of the other injection tube was opened outside the sheath tube, and grout was separately injected into and outside the sheath tube. It is characterized by.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A caisson anchor structure and a method for constructing the caisson according to the present invention will be described below in detail with reference to an embodiment shown in the drawings. 1 to 9 show the construction method according to the order of the working steps. Hereinafter, the construction method of the present invention will be described mainly with reference to FIGS. 1 to 9, but the caisson anchor structure of another invention will be clarified in the course of the description of the construction method.

(1) Step of Drilling a Vertical Hole and Step of Inserting and Installing a Lower Anchor Member (See FIG. 1) Caisson 6 described later in the pneumatic caisson method
Is set by the drilling machine 10 on the ground (ground surface) G above the ground S to be set, which is finally set by sinking.
While press-fitting a, a plurality of vertical holes 1 extending below the ground S to be set of the caisson 6 are formed at appropriate intervals in a plane. In addition, the code | symbol W has shown an example of the water level of the groundwater.

Next, a rod-shaped lower anchor member 3 is suspended from each vertical hole 1 using a crane 20 or the like, and is installed at the bottom of the vertical hole 1. Each lower anchor member 3 shall be installed at a position such that its upper end protrudes upward from the ground S to be set of the caisson 6. Reference numeral 2 denotes a suspended steel wire connecting the hook of the crane 20 and the lower anchor member 3. The upper end side of the suspended steel wire 2 after the lower anchor member 3 is hung by the crane 20 or the like so that the installation depth does not fluctuate due to the sinking of the lower anchor member 3 due to its own weight until the grout 5 is injected and solidified as described below. It may be attached to an appropriate fixed object on the ground G. The insertion and installation of the lower anchor member 3 can also be performed manually by an operator by appropriately installing a manually wound winch or the like.

The lower anchor member 3 may be, for example, a single steel rod (not shown) having an uneven surface.
In this embodiment, as shown in FIGS. 10 and 11, a rope-shaped unit anchor member 31 formed by twisting steel wires is bundled at a small interval by a plurality of spacers 32.

A steel sheath bellows tube or other sheath tube 33 having irregularities on its inner and outer surfaces is fixed around the plurality of unit anchor members 31 via plug means 34 and the like described later. Unit anchor members 31 inside the
In the central part of the tube, two injection tubes 4, 4 for grout injection are provided.
Are attached along the length direction of the unit anchor member 31. As the injection tube 4, for example, a vinyl chloride tube or the like is used.

The tip 41 of one injection tube 4 is opened inside the sheath tube 33, and the tip 42 of the other injection tube 4 is opened outside the sheath tube 33. The upper ends of the injection pipes 4 and 4 are all projected above the ground G. The injection pipes 4, 4 are both suspended when the lower anchor member 3 is suspended.

In FIGS. 10 and 11, reference numeral 34a denotes a partition plate provided at a lower end portion of the sheath tube 33 at an interval.
Reference numeral 34b denotes a sealing material such as a mortar or a waterproof material made of steel or the like filled between the upper and lower partition plates 34a, 34a, and these members 34a, 34b are used to inject one of the materials into the sheath tube 33 as described later. Internal grout injected through tube 4 is sheath tube 3
While constituting the plug means 34 for preventing it from flowing out of the outside 3, it serves to fix the sheath tube 33 to the unit anchor member 31.

Reference numeral 35 indicates that when the lower anchor member 3 is hung, the open end 42 of the other injection pipe 4 for discharging the external grout does not abut against the bottom of the vertical hole 1 to be closed. In order to achieve this, an end cap having a grout discharge port 35a on the side, which is attached and fixed to the distal end portion of the sheath tube 33, is indicated by reference numeral 36.
In order to allow the sheath tube 33 to occupy a concentric position with respect to the vertical hole 1, that is, the casing 10 a which is press-fitted by the drilling machine 10 for drilling the vertical hole 1 when the is suspended. And a guide member provided around the sheath tube 33. Further, reference numeral 37 denotes a synthetic resin tube coated with rustproof oil applied to the upper end portion of each unit anchor member 31 and then non-adhered and movably covered.

(2) Grout injection step (FIG. 2, FIG. 3,
After the insertion and installation of the lower anchor member 3, as shown in FIG.
The grout is mixed with cement, sand, an appropriate admixture and water by the grout mixer 30, and the grout is used by using a grout injector 40 such as a grout pump. Are injected into each vertical hole 1 at a required pressure through the injection pipes 4 and 4. The grout components used here are not limited to those described above. 2 in FIG.
Numeral 0a denotes a grout injection machine hose, and the ground G of each injection pipe 4
It is connected to the upper end protruding upward.

The grout is first injected inside the sheath tube 33 by one injection tube 4, and then outside the sheath tube 33 by the other injection tube 4. One injection tube 4 and sheath tube 3
The internal grout 5 injected into the inside 3 has a lower end with a plug means 34.
The inside of the sheath tube 33 sealed with is filled over the entire length. Then, in the sheath tube 33, the lower anchor member 3 inserted therethrough is buried by the internal grout 5 slightly over the upper end.

The external grout 5 injected from the lower end opening of the other injection pipe 4 is connected to the end cap 3 of the sheath pipe 33.
5 is discharged to the outside from a discharge port 35a provided therein, and is filled upward from below while excluding groundwater present between the outer surface of the sheath tube 33 and the inner wall of the vertical hole 1. The outer grout 5 to be filled has its uppermost surface at least reaching the ground S to be set of the caisson 6. The casing 10a press-fitted when drilling the vertical hole 1 is pulled out by the drilling machine 10 when the external grout 5 is injected. In all the vertical holes 1, as shown in FIG. 3, when the injection grout 5 for fixing the lower anchor member 3 is filled,
At the next operation step, the grout 5 is solidified.

In this embodiment, the sheath tube 33 attached at a distance around the lower anchor member 3 is fixed to the lower anchor member 3 in the vertical hole 1 in a biased manner, or the lower anchor member 3 is fixed in the presence of groundwater. This is to eliminate the inconvenience that the attachment strength of the lower anchor member 3 to the ground is weakened, for example, by decreasing the adhesion of the grout 5 to the surface of the lower anchor 3.

Further, since the lower ends of the injection pipes 4 and 4 are fixed to the lower anchor member 3 in this example, they remain as a part of the lower anchor member 3 even after the completion of the anchor structure of the present invention. Will be.

However, each of the injection pipes 4 and 4 has an internal grout 5
The filling tube 4 may be drawn out while filling with, and then the filling tube 4 may be drawn out while filling the external grout 5. When the sheath tube 33 is not provided, the grout injection tube 4 is of course one, and can be separately inserted into the vertical hole 1 without being fixed to the lower anchor member 3. The entire tube 4 can be withdrawn from the well 1 after grouting.

(3) Step of installing caisson on the ground and fixing upper anchor member (see FIG. 4) At least the lower part 61 of the reinforced concrete caisson 6 is constructed on the ground G at a predetermined position above the ground S where the caisson is to be set. Installed, ceiling slab 6 of the work room 62
3, a plurality of rod-shaped upper anchor members 7 made of a steel round bar or the like corresponding to the position of the lower anchor member 3.
Is embedded and fixed such that the lower end protrudes or is exposed in the working chamber 62.

When a protective cap (not shown) made of synthetic resin, rubber, or the like is detachably fitted to the lower end of each upper anchor member 7, it is safe in the subsequent work in the work chamber 62. Further, the upper end of the upper anchor member 7 may be straight, but is preferably bent in a U-shape as shown in the figure because the fixing strength of the caisson 6 to the ceiling slab 63 is enhanced. Further, the upper anchor member 7
The upper end of the caisson 6 can be hooked or welded to a reinforcing steel bar (not shown) before the concrete of the caisson 6 is cast.

(4) Caisson subsidence process (see FIG. 5) The excavator 50 is installed in the work room 62 of the caisson 6 constructed and installed on the ground G, and the soil at the bottom of the work room 62 is excavated to remove the caisson 6. Settle to the set ground S. At this time, the suspended steel wire 2 and the injection pipe 4 that continuously appear in the working chamber 62 with the excavation are cut or otherwise appropriately cut so as not to hinder the excavation. In the figure, reference numeral 64 denotes a peripheral wall made of reinforced concrete which is a part of the caisson 6 constructed on the lower portion 61 of the caisson 6, and 65 denotes a peripheral wall constructed on the caisson peripheral wall 64. A partition wall to be removed, 67 is a man lock on a man shaft 66 erected in communication with the working chamber 62, 69 is a working chamber 62
A material lock 60 on the material shaft 68 erected in communication with the caisson 6 is a water load of the caisson 6. These parts or facilities are all constructed or used in the currently practiced pneumatic caisson method and are known. The above-mentioned excavator 50 is removed when the caisson 6 is lowered to a predetermined set ground S.

(5) Step of joining upper and lower anchor members (see FIG. 6) In the working chamber 62 of the caisson 6 after sinking, the lower ends of the plurality of upper anchor members 7 projecting from the ceiling slab 63 and the set ground The upper ends of a plurality of corresponding lower anchor members 3 protruding from S are connected to each other by connecting means 8.

The connecting means 8 used in this embodiment
As shown in FIG. 13, the first connecting block 81 inserted into the lower end of each upper anchor member 7 is attached to the upper anchor member 7 with a locking nut 82 screwed from below so as not to come off. The second connection block 83 inserted through the upper end of the anchor member 3 is fixedly attached by wedge means 84, and a plurality of connection bolts 85 inserted through the first and second connection blocks 81 and 83 together.
The first and second connection blocks 81 and 83 are mutually called by nuts 86 screwed to the connection bolts 85, and the upper anchor member 7 and the lower anchor member 3 are connected in a tensioned state. . In addition, each vertical hole of the first connection block 81 may be a female screw hole, and may be screwed to each upper anchor member 7.
The connection block 81 and the connection bolt 85 may be screwed together.

[0029] More specifically, the wedge means 84
Outside the second connection block 83 (upper surface side), a plurality of unit anchor members 3 constituting each lower anchor member 3
A wedge receiver 84b at the front end (upper end) of the device 1 via a seat plate 87
Is inserted, and the wedge piece 84a is driven into the insertion hole of the wedge receiver 84b so as to be inserted between the plurality of unit anchor members 31.

In FIG. 13, reference numeral 88 denotes a cap fixed to the upper surface of the second connecting block 83 via the above-mentioned seat plate 87 with a set screw or the like so as to surround the upper end of the lower anchor member 3. A small hole 88a provided in the top of the cap body 88
Through which a rust preventive 89 is filled. Each member constituting the connecting means 8 in this example can be made of steel except for the rust preventive 89.

FIG. 14 shows another example of the connecting means 9. The connecting means 9 in this example includes a first bolt 91 and a turnbuckle 9 screwed to the bolt 91 in order from the top.
2. The second bolt 9 screwed to the turnbuckle 92
3 and a sleeve joint 94 fixed to the lower end of the second bolt 93 by screwing or welding.
Each of the members constituting the connecting means 9 may be made of steel.

The upper anchor member 7 to be connected by the connecting means 9 is a rod-shaped anchor member body 71 whose upper end is bent in a U-shape and a screw coupler screwed to the lower end of the anchor member body 71. And both members 71 and 72 are embedded in the ceiling slab 63,
The lower end of the screw coupler 72 is exposed to the working chamber 62.

Accordingly, the upper end of the first bolt 91 in the connecting means 9 is screwed to the lower end of the screw coupler 72 in the upper anchor member 7, and the lower end of the sleeve joint 94 in the connecting means 9 is connected to the lower anchor member 3. The upper anchor member 7 and the lower anchor member 3 are joined by being fitted to the upper end and fixed by welding or crimping. In this connecting means 9, the turning operation of the turn buckle 92 adjusts the entire length of the connecting means 9, and controls the upper anchor member 7 and the lower anchor member 3.
Enables the connection in a tension state.

As means for connecting the upper anchor member 7 and the lower anchor member 3, the above two examples 8, 9 are used.
Instead of this, it is needless to say that any known means can be adopted as long as it is a connecting means between two rod-shaped bodies, although not shown.

When the connection between the upper anchor member 7 and the lower anchor member 3 by the connecting means 8 is completed, the water load 60 is discharged from the caisson 6 and the outfitting, that is, the man shaft 66, the man lock 67, the material shaft 6
8 and the material lock 69 are removed.

(6) Casting concrete filling step (see FIGS. 7 to 9) After the water load 60 has been discharged and the outfitting has been removed, as shown in FIG. Casts and fills the embedded concrete 101, and fills the embedded concrete 1
At 01, the projecting lower ends of all the upper anchor members 7 into the working chamber 62, the projecting lower ends of the lower anchor members 3 into the working chamber 62, and the connecting means 8 connecting them are buried. Here, the characteristic part of the caisson anchor structure according to the present invention is completed.

Thereafter, as shown in FIGS. 8 and 9, the hollow portion of the caisson 6 is filled with the filling water 102, and the reinforced concrete is formed on the uppermost portion, similarly to the construction of the basic structure by the conventional pneumatic caisson method. Is constructed. Reference numeral 104 denotes a structure such as a bridge pier constructed on the top plate 103, and reference numeral 105 denotes a backfilled portion made of soil which is made flush with the ground G after removing the partition wall 65.

[0038]

According to the caisson anchor structure and the construction method of the invention described above, the following effects can be obtained. According to the anchor structure of the present invention, the caisson as a basis of the structure supported on the setting ground is provided between the caisson and the setting ground, and is firmly connected to each other through the connecting means. The supporting condition is reinforced by the upper and lower anchor members joined together, so that even if a large earthquake or large ground loosening occurs, the caisson does not tilt with the supporting structure, making it extremely safe. is there. In addition, as the stability of the basic caisson is improved on the ground, the cross-sectional area of the caisson can be reduced and the weight of the caisson's body can be reduced, so that the cost of building the basic caisson can be reduced . Since the anchor structure using the connecting means according to claim 2 or 3 can be constructed in a state where the upper and lower anchor members are tensioned, damage to the anchor member due to bending can be prevented, and its function can be maintained for a long time. Can be demonstrated. According to the method for constructing an anchor structure of the present invention, there is an advantage that the anchor structure of a caisson of another invention can be rationally and efficiently constructed and provided. According to the construction method of claim 5, since each lower anchor member is an aggregate of a plurality of unit anchor members, the mounting area of the lower anchor member in the vertical hole is increased by increasing the contact area of the grout with the lower anchor member. Can be enhanced. According to the construction method of claim 6, since the sheath tube is fixed around the lower anchor member and grout can be separately injected into and out of the sheath tube, the lower anchor member may be biased in the sheath tube. In addition, the inner grout adheres to the lower anchor member and the inner surface of the sheath tube, and the outer grout adheres to the outer surface of the sheath tube and the inner wall of the vertical bore. Therefore, the fixing state of the lower anchor member to the vertical hole is extremely stable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an outline of a step of forming a vertical hole and a step of inserting and installing a lower anchor member in an embodiment of a method for constructing a caisson anchor structure according to the present invention.
(However, in this figure, the illustration of the grout injection pipe suspended with the lower anchor member is omitted.)

FIG. 2 is a longitudinal sectional view showing an outline of a grout injection step in the embodiment of the construction method. (However, in this figure, the entry of the suspended steel wire for suspending the lower anchor member is omitted.)

FIG. 3 is a longitudinal sectional view showing an outline at the end of a grout injection step.

FIG. 4 is a longitudinal sectional view showing an outline of a caisson installation on the ground and a fixing process of an upper anchor member.

FIG. 5 is a longitudinal sectional view showing an outline of a caisson sinking process.

FIG. 6 is a longitudinal sectional view showing an outline of a joining process of an upper anchor member and a lower anchor member.

FIG. 7 is a longitudinal sectional view showing an outline of a step of placing concrete in the same manner. Is

FIG. 8 is a longitudinal sectional view showing an outline of a state in which an anchor structure of a caisson is completed by pouring infill concrete.

9 is a transverse sectional view taken along line IX-IX in FIG.

FIG. 10 is a vertical sectional front view showing an outline of a lower anchor member inserted into a vertical hole.

11A is an enlarged cross-sectional plan view taken along line XIA-XIA in FIG. 10, FIG. 11B is an enlarged cross-sectional plan view taken along line XIB-XIB in FIG. 10, and FIG. It is an expansion vertical front view of a part.

FIG. 12 is a longitudinal sectional front view showing a state in which an outer grout is provided outside a sheath tube and an inner grout is provided inside a sheath tube.

FIG. 13 is a front view showing an outline of a connecting means in which the upper anchor member and the lower anchor member are connected in the embodiment.

FIG. 14 is a front view showing the outline of another connecting means.

15A and 15B show a state where a conventional caisson is sunk, wherein FIG. 15A is a longitudinal sectional front view, and FIG. 15B is a plan projection view showing a state where the caisson is supported by a supporting ground G1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Drilling machine 10a Casing 20 Crane 30 Grout mixer 40 Grout injection machine 40a Hose 50 Excavator 60 Water load 1 Vertical hole 2 Suspended steel wire 3 Lower anchor member 31 Unit anchor member 32 Spacer 33 Sheath tube 34a Partition plate 34b Sealing material 34 stopper means 35 end cap 35a grout outlet 36 guide member 37 tube 4 injection pipe 41 tip of one injection pipe 42 tip of other injection pipe 5 grout 6 caisson 61 lower part 62 work room 63 ceiling slab 64 caisson peripheral wall 65 partition Wall 66 Man shaft 67 Man lock 68 Material shaft 69 Material lock 7 Upper anchor member 71 Anchor member main body 72 Screw coupler 8 Connecting means 81 First connection block 82 Lock nut 83 Second connection block 84 Kusa Wedge piece 84a wedge piece 84b wedge receiver 85 connecting bolt 86 nut 87 seat plate 88 cap body 88a small hole 89 rust preventive agent 9 another connecting means 91 first bolt 92 turnbuckle 93 second bolt 94 sleeve joint 101 concrete filling 102 Filling water 103 Top plate 104 Structure 105 Backfilling part G Ground S Ground to be set, Ground to be set W Groundwater level

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Koichi Fujita 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo Co., Ltd. (72) Inventor Yukio Kato 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo Shiraishiuchi ( 72) Inventor Tomihiko Yanagisawa 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo (72) Shiroishiuchi Inventor Masamichi Suzuki 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo Shiroishiuchi (72) Inventor Shun Ando Tokyo 1-14 Kanda Iwamotocho, Chiyoda-ku Co., Ltd. (72) Inventor Hiroshi Too 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo Co., Ltd. (72) Inventor Mamoru Aoyagi 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo Shiroishiuchi (72) Inventor Yoshinao Kurachi 1-14 Kanda Iwamotocho, Chiyoda-ku, Tokyo 1-14 Shiraishiuchi (72) Inventor Taro Iwamoto, Tokyo 1-14 Kanda Iwamotocho, Ta-ku Shiraishinai (72) Inventor Tsubasa Kubota New Design Co., Ltd. 2-11-2 Iwamotocho, Chiyoda-ku, Tokyo (56) References JP-A-4-68123 (JP, A) JP-A-11-117321 (JP, A) JP-A-59-34332 (JP, A) JP-A-4-128434 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) E02D 23/08 E02D 3/12 101 E02D 27/20 E02D 27/00

Claims (6)

(57) [Claims] 1. A lower anchor member is inserted into each of a plurality of vertical holes drilled at an appropriate interval in a setting ground of a caisson, and the lower anchor members in the respective vertical holes are fixed by solidifying an injection grout. A plurality of upper anchor members are buried and fixed to the ceiling slab of the caisson work room corresponding to the positions of the plurality of lower anchor members, and the lower ends of the corresponding upper anchor members and the upper ends of the lower anchor members are connected to each other. An anchor structure for a caisson, wherein the anchor structure is formed by joining concrete by means of a concrete buried in a caisson work room. 2. The first connecting block attached to the lower end of the upper anchor member, the second connecting block attached to the upper end of the lower anchor member, and the first and second connecting blocks. To attach and combine,
2. The caisson anchor structure according to claim 1, wherein the anchor structure comprises a plurality of connecting bolts inserted into the first and second connecting blocks and nuts respectively screwed to the connecting bolts. 3. A first bolt having an upper end screwed to a screw coupler provided in an upper anchor member, a turnbuckle having an upper end screwed to a lower end of the first bolt, and the turnbuckle having the coupling means. A second bolt having an upper end screwed to a lower end of the second bolt, and a sleeve having an upper end fixed to the lower end of the second bolt by screwing or welding, and a lower end fitted to an upper end of the lower anchor member and fixed by welding or crimping. 2. The caisson anchor structure according to claim 1, wherein the anchor structure comprises a joint. (A) drilling a plurality of vertical holes under the caisson's planned ground with a drilling machine at appropriate intervals in the ground above the planned ground of the caisson;
(B) a step of inserting a lower anchor member into each vertical hole and installing it at the bottom of the vertical hole; (C) grout is injected into each vertical hole through an injection pipe, and the lower anchor member is fixed in the vertical hole by solidification. (D) installing a reinforced concrete caisson on the ground on the ground to be set, and burying and fixing a plurality of upper anchor members in the ceiling slab of the lower working room corresponding to the position of the lower anchor member; (E) a step of excavating the lower surface of the caisson work chamber and lowering it to a predetermined position; (F) connecting a lower end of each upper anchor member and an upper end of each lower anchor member projected or exposed into the work chamber of the caisson by connecting means. And (G) above the lower end portion and the lower anchor member of the upper anchor member connected by connecting means in the caisson's work room by placing concrete infill in the work room. Construction method of the anchor structure of caisson, characterized in that it comprises a step of embedding the section. 5. The caisson anchor according to claim 4, wherein each of the lower anchor members is formed as an aggregate of a plurality of unit anchor members, and a contact area of the grout with the lower anchor member is increased. Construction method of the structure. 6. A sheath tube is fixed around each of said lower anchor members, and tip portions of two grout injection tubes inserted into the sheath tubes are attached to the lower anchor member. The tip of one injection tube is opened inside the sheath tube, the tip of the other injection tube is opened outside the sheath tube, and grout is separately injected into and outside the sheath tube. Item 6. The method for constructing a caisson anchor structure according to item 4 or 5.