JP3255894B2 - Steel tower base structure and its 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 foundation structure for fixing and installing legs of a tower or a temporary tower for overhead power transmission lines and a method of constructing the foundation.

[0002]

2. Description of the Related Art A tower for an overhead power transmission line is buried in the ground in order to fix a leg at the bottom of the tower at an installation location, and the leg is connected to the leg base and fixed. The footing foundation is
A buried hole is dug in the setting place, and in the buried hole, the foundation leg material is connected to the member installed at the bottom of the hole, then concrete is poured into the buried hole and the whole is solidified and integrated and fixed to the surrounding land You.

[0003] With respect to an overhead transmission line constructed using a tower installed in this way, the tower is used for a long time and becomes old, or the tower height needs to be increased due to power transmission circumstances. For this reason, the tower may be replaced.
In such a case, a temporary tower is installed adjacent to the original tower,
Temporarily moving the overhead power transmission line to the temporary tower and supporting it, removing the original tower together with its footing foundation, installing a new tower and footing foundation, and then returning the overhead transmission line to its original state Done.

Japanese Unexamined Patent Publication No. Hei 9-111775 proposes a leg material basic structure capable of easily and safely installing the above temporary iron tower by placing a casting block in a shallow excavation hole and a temporary construction method thereof.

[0005] In this method, a cast iron block is used as a base material for a temporary iron tower. In the method, a flat cast block is provided with an uneven portion around the outer periphery of the cast iron block so that the same soil can be fitted to each other. Placing the floor plate material in the excavation hole, providing the leg material mounting beam on the floor plate material, stacking a large number of the casting blocks on the floor plate material and laying it down to secure a sufficient lifting support force, It is used in a structure in which four legs of a steel tower are integrated.

[0006]

By the way, the footing base for the temporary tower, which is temporarily installed at the time of the above-mentioned tower replacement work,
In the method of burying the footing foundation in a deep excavation hole and hardening it with concrete, the same design as the legroom foundation that is provided normally is also installed at the temporary location, and the new footing foundation is installed at the original position. Once installed, the overhead power lines will be moved to the new tower,
The footing base for the temporary tower will be removed.

However, in this case, since the base of the leg material is entirely hardened with concrete, it is extremely difficult to break the concrete and take it out of the excavation hole, and it takes a lot of labor and time, and replacement work is required. Costs will be higher. Also, the removed foot material foundation is destroyed and cannot be reused, and must be treated as industrial waste.

In the case of a method using a casting block, the drilling hole is shallow, a floor plate is placed in the hole, and the casting block is stacked thereon, so that the construction is simple and the work safety is sufficient. Although it is possible to reuse the substructure, it is necessary to use a flat and large area to obtain the bearing capacity to support the tower and the lifting capacity, so its use is limited to temporary towers on flat ground. Have been. Therefore, it cannot be used even if it is intended to be used for a legged foundation structure as it is for a temporary tower.

The present invention is based on the above-mentioned various problems of the conventional steel tower base material foundation structure, and is simple in construction, has sufficient structural safety, sufficient bearing strength, and sufficient pulling support force, and has a basic structural member. An object of the present invention is to provide a foundation structure for each leg of a tower that can be reused and can be constructed at an economical cost.

[0010]

According to the present invention, as a means for solving the above-mentioned problems, a support column is disposed in a dug hole for installing a steel tower leg member by connecting a support leg portion to a lower end thereof.
A liner plate is attached along the peripheral wall of the excavation hole, the improved soil is loaded between the liner plate and the peripheral wall of the hole, and the support columns and the support legs are connected to the upper and lower portions of the liner plate by connecting members, respectively.
The foundation structure of the steel tower legs was constructed by burying the soil in the space inside the hole.

The basic structure of the present invention having the above-described structure supports the steel tower legs with sufficient supporting strength and pull-out supporting force, and is used as a permanent foundation as well as the temporary iron tower. Since the supporting columns installed in the excavation hole are connected to the liner plate by the connecting members, the horizontal force acting on the supporting columns is transmitted to the ground via the liner plate and statically supported by the reaction force.

In addition, since the improved soil is loaded into the gap between the liner plate and the peripheral wall, the adhesion to the ground is enhanced, and the soil is buried in the space in the hole. Supporting strength and pulling-up supporting force are ensured, so that it supports the tower leg material and has sufficient strength against side-down force.

As a construction method for forming the above-mentioned basic structure,
The excavation hole is dug at the installation position of the steel tower leg material, a liner plate is attached along the peripheral wall of the excavation hole, a support pillar having a support leg at the lower end is inserted into the excavation hole, and the liner plate and the peripheral wall are connected. It is possible to employ a construction method of a steel tower leg base material structure in which the improved soil is charged in the middle and the excavated soil is backfilled in the space in the hole.

According to this method, after the liner plate is attached to the excavation hole, the support pillar is inserted, and the improved soil is filled between the hole and the liner plate. May be performed first or may be performed in parallel. The bearing capacity and pull-out bearing capacity are enhanced by backfilling the soil in the space, but this soil is used by using excavated soil.

When the basic structure is removed, it can be easily and completely removed by the operation opposite to the above-mentioned method, and the basic structure can be reused because the basic structure is taken out without being destroyed. It is not necessary to process as

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main vertical cross-sectional view of a steel tower leg base structure according to an embodiment. Although the steel tower base material basic structure of this embodiment is mainly intended for a temporary steel tower, it may be used as it is for an original steel tower. As shown in the figure, the tower base material base structure is formed in a ground G at a temporary position of a steel tower with a drilled hole 10 having a predetermined depth.

In the above-mentioned tower tower base material basic structure, a support column 11 having a support leg 12 at a lower end is provided in a drilling hole 10, and a liner plate 13 is attached along a peripheral wall of the drilling hole.
a, a connecting member 14a for connecting the upper liner plate 13a to the upper portion of the supporting column, and a connecting member for connecting the lower liner plate 13b to the supporting leg. 14b is attached, and the space in the hole is backfilled with soil.

As shown in the figure, a steel pipe of sufficient strength is used for the support column 11, a short pipe C for connecting to a steel tower leg is connected to the upper end, and the support leg 12 at the lower end is as shown in FIG. As shown, a plurality of leg members 12a (six in the illustrated example) extending horizontally from the lower end of the support column 11 and a collecting plate 12t attached to the lower end from the middle of the support column 11 radially diagonally downward. A plurality (six) of extending leg members 12b are provided.

The liner plate 13 is formed by forming a plate having a corrugated cross section in a ring shape along the entire peripheral wall of the excavation hole 10, and is attached so as to be of a certain size in the height direction and to be stacked in a plurality of upper and lower stages. Upper liner plate 1 of liner plates 13
Improved soil 15 is charged and loaded between each of the lower liner plate 3a and the lower liner plate 13b and the peripheral wall in order to increase the degree of connection. In addition, the liner plate is discontinuous by a certain size between the lower liner plate 13b and the liner plate above the lower liner plate 13 for improved soil injection.

The improved soil 15 includes upper and lower liner plates 1.
It is injected into a gap (10 cm in the illustrated example) formed between the excavated peripheral wall and the hole diameter slightly larger than 3a and 13b, and solidified. This improved soil is formed by mixing the excavated soil, the solidifying agent, and water with stirring and injecting and curing into the gaps. The solidifying agent is a cement-based solidifying agent, which is an inorganic material used for solidifying general soft ground. For example, an improved soil is prepared by well stirring and mixing 200 kg of solidifying agent and 400 kg of water with respect to 1 m ³ (1600 kg) of excavated soil.

The upper liner plate 13a is connected and fixed to the upper end of the support column 11 at a plurality of locations by a connection frame 14a as shown in the figure, whereby the horizontal force of the force transmitted from the tower leg material to the support column is provided. I am receiving it. The lower liner plate 13b is connected to the support leg 12 via a reinforcing connection member 14b.

The lower liner sheet 13b, as shown in FIG. 4 (b), is fixed by fixing strength by improving soil 15 injected between the slightly larger diameter 10 _R wall of the inner peripheral wall of the drilling hole 10, A connecting piece 14b is connected to an upper end of the lower liner plate 13b by a connecting piece, and a lower end of the connecting pillar 14b is connected to the supporting leg 12 by a bracket to form the supporting leg 1b.
2 is connected to the lower liner plate 13b. in this way,
The pull-out strength of the support column 11 is obtained through the lower liner plate 13b and the improved soil 15, and in order to increase the pull-out strength, the bottom of the excavation hole is widened and excavated to increase the pull-out strength.
b, interposing a coupling piece 13 _Y for coupling the connecting member 14b to the widened hole section.

Support column 11, support leg 12, liner plate 1
3. When the connecting member 14 and the improved soil 15 are assembled in the state shown in the cross section of FIG. 1, the remaining space of the excavation hole 10 is backfilled with the soil 16 existing before the first excavation of the hole. This completes the basic structure.

The tower base material base structure having the above-described structure supports the tower base material with sufficient strength, and can be used without any deformation even when used for a long period of time. When this foundation structure is used as a footing foundation for a temporary tower, it is relatively easy to remove it from the excavation hole at the installation position, and the material of the removed foundation structure can be reused.

The construction method for assembling the above-mentioned basic structure is as follows.
This is performed according to the procedure shown in FIG. First, a circular excavation hole 10 shown in FIG. 5A is excavated at the installation position of the foundation structure (in the illustrated example, the diameter is about 3 m and the depth is 3 to 4 m). This excavation is performed with a mechanical force of a shovel or the like until the rough hole is formed, but the peripheral wall and the lower bottom for accurately finishing the hole diameter are finished by hand digging.

Thereafter, the liner plate 13 is set along the peripheral wall of the hole (FIG. 7B). The liner plate 13 is buried in a corrugated plate that is divided into a plurality of steps (6 to 8 steps) in the depth direction and a plurality of sections (equally divided into 4 to 6) in the radial direction so as to be entirely circular along the hole peripheral wall. Join the joints of each split liner plate with bolts and nuts.

Next, as shown in FIG. 3C, a support column 11 having a support leg 12 is inserted into the excavation hole 10. The support leg portion 12 and the support column 11 may be previously assembled integrally on the ground, and both may be hung and lowered into the hole for installation, or both may be separately put in the hole and assembled in the hole. In the hole, the end of the radial frame of the support leg 12 is connected to the connection column 14b. The upper connecting member 14a is also attached to the upper liner plate 13a via the connecting flange 13x and the connecting bracket 14c. Further, as shown in FIG. 3D, the improved soil 15 is sent out from the pump P into a gap between the upper peripheral liner plate 13a and the lower peripheral liner wall of the lower liner plate 13b, and injected from the end of the hose. The liner plate 13 is cut by a short dimension between the lower liner plate 13b and the intermediate portion so that the improved soil 15 can be injected into the back side of the lower liner plate 13b.

When the support pillar 11 and the support leg 12 are fixed in the hole, the soil 16 dug by excavation is then backfilled as shown in FIG. At this time, the soil is compacted with a vibrator at each height as the height is gradually increased so that the soil becomes the same as the original ground. When the soil is backfilled and solidified to the original ground level, the construction of the foundation structure is completed.

FIG. 6 is a diagram showing the relationship between the tower and the base structure of the tower leg material. As can be seen from the figure, the lower end of the tower leg is connected by connecting the four legs F of the tower to the flange of the short pipe C on the upper part of the support column 11.

In the above embodiment, the improved soil is filled between the liner plate and the peripheral wall after the support pillar is inserted, but the order may be reversed.

[0031]

As described in detail above, the tower base material base structure of the present invention has a support pillar inserted in a digging hole, a liner plate is attached to a peripheral wall of the hole, and an improvement is provided between the liner plate and the peripheral wall. Put the soil, connect the liner plate and the support pillar with the connecting member, and bury the soil in the space space, so that horizontal strength, gravity, supporting strength against overturning moment, pull-out supporting force without using concrete However, the temporary tower can of course be used as a foundation for the original tower, which is easy to assemble, can be manufactured at economical cost, and can be reused even if it is removed from the hole, and therefore industrial waste Various advantages are obtained, such as being usable without becoming a product.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view of a steel tower leg base structure according to an embodiment.

FIG. 2 is a plan view as viewed from an arrow II-II in FIG. 1;

FIG. 3 is a plan view seen from an arrow III-III in FIG. 1;

FIG. 4 is a partial sectional view of the above.

FIG. 5 is an explanatory view of a construction method.

FIG. 6 is an explanatory diagram showing a relationship with tower leg materials.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Drilling hole 11 Support pillar 12 Support leg 13 Liner board 15 Improved soil 16 Soil

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Shikata 3-3-22 Nakanoshima, Kita-ku, Osaka Kansai Electric Power Company (72) Inventor Masaaki Ikemoto 3-2-2 Nakanoshima, Kita-ku, Osaka Kansai Electric Power (72) Inventor Yuzo Morinaga 3-3-22 Nakanoshima, Kita-ku, Osaka-shi Kansai Electric Power Co., Ltd. (72) Inventor Shuji Nagao 3-2-2, Nakanoshima, Kita-ku, Osaka Kansai Electric Power Co., Ltd. 72) Inventor Tsutomu Ikeda 2-3-1, Honjohigashi, Kita-ku, Osaka-shi Kindennai Co., Ltd. (72) Inventor Hideo Miyamoto 2-3-1, Honjohigashi, Kita-ku, Osaka-shi Kindenuchi Co., Ltd. (56) References JP-A-64-34383 (JP, A) JP-A-9-111775 (JP, A) JP-A-2000-204569 (JP, A) JP-A-48-6852 (JP, Y1) (58) Int.Cl. ⁷ DB name) E02D 27/42

Claims (3)

(57) [Claims] 1. A support pillar is connected to a support leg at a lower end thereof in an excavation hole for installing a tower leg material, and a liner plate is attached along a peripheral wall of the excavation hole. The improved structure is loaded between them, and the supporting columns and supporting legs are connected to the upper and lower parts of the liner plate by connecting members, respectively, and the soil is buried back in the space in the hole. 2. An improved soil is loaded between an upper liner plate from the upper end of the hole to a predetermined depth and a lower liner and a peripheral wall from the bottom of the hole to a predetermined height, and the lower liner plate and the upper part of the liner plate above the liner plate. The steel tower base material base structure according to claim 1, wherein a liner plate is provided discontinuously by a fixed size between the liner plate and the soil for improved soil injection. 3. A drilling hole is drilled at a position where a steel tower leg material is to be installed, a liner plate is attached along a peripheral wall of the drilling hole, a support pillar having a support leg at a lower end is inserted into the drilling hole, and the liner is inserted. A method of constructing a steel tower footing foundation structure in which improved soil is loaded between a plate and a surrounding wall, and the excavated soil is backfilled in the space in the hole.