Foundation blocks, method for constructing foundation structures, and foundation structures

Abstract

The object of the present invention is to solve the problems of the prior art, namely, to provide a foundation block, a method for constructing a foundation structure, and a foundation structure that can construct a support structure for electrical equipment in a shorter period of time compared to the prior art. [Solution] The foundation block of the present invention is a precast foundation block that constitutes the foundation structure of electrical equipment, and includes ordinary foundation blocks and perforated foundation blocks. The foundation structure is formed by arranging the ordinary foundation blocks and perforated foundation blocks in a single row in the direction of the foundation axis, and then installing joint materials in the joint box cutouts. The electrical equipment is then placed on the foundation structure so that the leg anchors are accommodated in the anchor housing holes, and the electrical equipment can be firmly supported by filling the anchor housing holes with filler material.

Description

Technical Field

[0001] The present invention relates to a technology for supporting electrical equipment such as transformers, and more specifically, to a foundation block that enables construction of a support structure for electrical equipment in a shorter period of time compared to conventional technologies, a foundation structure constituted by the foundation block, and a method for constructing the foundation structure.

Background Art

[0002] Electric power of thousands to tens of thousands of volts is generated in power plants, and in order to avoid loss due to electrical resistance, the voltage is increased to an ultra-high voltage of approximately several hundreds of thousands of volts before power transmission. Then, the voltage is gradually reduced at each substation such as ultra-high voltage substations, primary substations, secondary substations, and distribution substations before being supplied to factories and the like, and further reduced by pole-mounted transformers and the like before being supplied to households. In any case, the electricity generated at power plants is supplied to consumers via transmission lines and distribution lines.

[0003] For example, if a 66kV transformer installed in an outdoor substation is placed directly on the ground, the 66kV transformer may suffer uneven subsidence or topple over during an earthquake. Therefore, 66kV transformers are usually placed on concrete slabs. More specifically, after excavating the ground surface, crushed stone is laid, leveling concrete is laid thereon, and then a concrete slab serving as the foundation for the 66kV transformer is constructed further thereon. Conventionally, when constructing this concrete slab, a cast-in-place concrete method has been employed as disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] To construct cast-in-place concrete, it is first necessary to design the concrete slab to be constructed. Specifically, based on the ground conditions (presence or absence of a bearing layer, physical properties such as cohesion c, internal friction angle φ, and unit weight γ) and the specifications of electrical equipment such as transformers (various dimensions, weight, center of gravity, etc.), various elements such as the dimensions of the concrete slab, reinforcement arrangement, and concrete mix design are determined after checking whether there will be insufficient support for the applied load and whether the electrical equipment will not overturn or slide.

[0006] Furthermore, constructing a concrete slab on-site involves numerous steps. Specifically, it involves first assembling the reinforcing bars, then assembling the formwork, pouring concrete while compacting it with a high-frequency vibrator, leveling the concrete surface with a trowel, curing it for a specified period, and finally removing the formwork to complete the project. Of these steps, assembling the reinforcing bars and formwork requires a certain level of experience and skill, and in particular, finishing the concrete surface with a trowel is an extremely delicate task that greatly affects the horizontal installation of electrical equipment. However, in today's labor shortage, it is becoming increasingly difficult to secure such workers.

[0007] Thus, the construction of cast-in-place concrete structures required a significant amount of work during both the design and construction phases, resulting in considerable time and cost. In particular, the curing period for the concrete to reach its full strength could last as long as 28 days, meaning that it took an extremely long time before transformers could be installed. The time it took to install the transformers meant that the start of their operation was delayed, which in turn meant that it took time for consumers to be able to use electricity. Moreover, in some cases, the electricity supply may have to be shut off until the transformers are installed, which has a particularly severe impact on consumers.

[0008] The object of the present invention is to solve the problems of the prior art, namely, to provide a foundation block, a method for constructing a foundation structure, and a foundation structure that can construct a support structure for electrical equipment in a shorter period of time compared to the prior art. [Means for solving the problem]

[0009] The present invention focuses on standardizing the foundation structure by adopting a standard design and utilizing precast foundation blocks in that foundation structure, and is based on an unprecedented idea.

[0010] The foundation block of the present invention is a precast foundation block that constitutes the foundation structure of electrical equipment, and is a set of foundation blocks that includes ordinary foundation blocks and perforated foundation blocks. The ordinary foundation block has a concrete body and a joint box cutout, while the perforated foundation block has a concrete body, a joint box cutout, and anchor housing holes. The concrete body is roughly rectangular in plan view, with the foundation axis direction of the foundation structure being the short side and the direction perpendicular to the foundation axis of the foundation structure being the long side. The joint box cutout is a box cutout formed on the surface of the foundation block that is perpendicular to the foundation axis (i.e., the surface that is the long side), and the anchor housing holes provided in the concrete body are holes that can accommodate the leg anchors of electrical equipment. The foundation structure is formed by arranging these ordinary foundation blocks and perforated foundation blocks in a single row along the foundation axis and then installing jointing materials in the joint box cutouts. The electrical equipment can then be firmly supported by placing it on the foundation structure so that the leg anchors are accommodated in the anchor housing holes, and then filling the anchor housing holes with filler material.

[0011] The present invention relates to a method for constructing a foundation structure for electrical equipment using a plurality of precast foundation blocks, and comprises a foundation layer formation step, a level layer formation step, a foundation block arrangement step, and a foundation block connection step. The foundation blocks include ordinary foundation blocks and perforated foundation blocks. Ordinary foundation blocks have a concrete body and a joint box cutout, while perforated foundation blocks have a concrete body, a joint box cutout, and anchor housing holes. In the foundation layer formation step, a foundation layer is formed on the ground from the bottom in the order of crushed stone layer and leveling concrete layer. In the level layer formation step, a self-leveling layer is formed by laying a self-leveling material on the upper surface of the foundation layer. In the foundation block arrangement step, a plurality of foundation blocks are arranged in a single row in the direction of the foundation axis on the upper surface of the self-leveling layer. In the foundation block connection step, adjacent foundation blocks are connected by installing a joint material in the joint box cutout of each adjacent foundation block in the direction of the foundation axis. The electrical equipment can then be firmly supported by placing it on the foundation structure so that the leg anchors are accommodated in the anchor housing holes, and then filling the anchor housing holes with filler material.

[0012] The foundation structure construction method of the present invention may further include a foundation block selection step. In this case, however, two or more types of foundation structures with different planar dimensions are set in advance as standard foundations, and two or more types of foundation blocks with different planar dimensions are prepared by dividing these standard foundations in the direction of the foundation axis. In the foundation block selection step, an appropriate type of foundation block is selected from two or more types of foundation blocks using a pre-created standard foundation judgment table. This standard foundation judgment table is created for each electrical equipment with different specifications, and also for each standard foundation, and further indicates the suitability of adopting that type of foundation block based on the ground physical properties and the design horizontal seismic intensity. In the foundation block selection step, the standard foundation judgment table related to the specifications of the target electrical equipment is used, and the appropriate type of foundation block is selected by comparing the standard foundation judgment table related to each type of standard foundation with the design horizontal seismic intensity corresponding to the construction site of the foundation structure, and the ground physical properties at the construction site. In this case, the foundation block placement step is to place the type of foundation block selected in the foundation block selection step.

[0013] The foundation structure construction method of the present invention can also be a method that uses a standard foundation judgment table created for each electrical equipment specification. In this case, even if the specifications of the electrical equipment are the same, if the specifications of the electrical equipment differ, for example, if the manufacturers are different, a separate (manufacturer-specific) standard foundation judgment table will be created for each. The electrical equipment specifications include at least the weight and center of gravity of the electrical equipment. In the foundation block selection process in this case, the appropriate type of foundation block is selected by comparing the standard foundation judgment table related to the electrical equipment specifications of the target electrical equipment with the design horizontal seismic intensity and ground physical properties.

[0014] The foundation structure construction method of the present invention may further include a foundation block arrangement planning step. In the foundation block arrangement planning step, the number of foundation blocks to be used and the arrangement (order) of ordinary foundation blocks and perforated foundation blocks are planned using a pre-created foundation block arrangement table. This foundation block arrangement table is created for each type of standard foundation and shows the number of foundation blocks to be used and the arrangement of ordinary foundation blocks and perforated foundation blocks according to the shape of the electrical equipment. The shape of the electrical equipment includes at least the planar dimensions of the electrical equipment and the position of the leg anchors. In this case, the foundation block arrangement planning step uses the foundation block arrangement table related to the type of foundation block selected in the foundation block selection step, and plans the number of foundation blocks to be used and the arrangement of ordinary foundation blocks and perforated foundation blocks based on the shape of the electrical equipment to be used. In the foundation block arrangement step, the foundation blocks are arranged according to the number and arrangement planned in the foundation block arrangement planning step.

[0015] The foundation structure construction method of the present invention may further include a foundation pile installation step and a foundation pile connection step. However, in this case, the foundation block includes a pile head foundation block. This pile head foundation block has a concrete body portion, a joint box cutout portion, and a pile head housing hole, of which the pile head housing hole is provided within the concrete body portion and penetrates the concrete body portion in the thickness direction. In the foundation pile installation step, foundation piles are installed, and in the foundation pile connection step, the foundation piles are connected to the pile head foundation block. In this case, in the foundation block placement step, the pile head foundation block is positioned so that the heads of the foundation piles are housed in the pile head housing hole, and in the foundation pile connection step, a filler material is filled into the pile head housing hole in which the heads of the foundation piles are housed.

[0016] The foundation structure of the present invention is a foundation structure for supporting electrical equipment, comprising a foundation layer, a self-leveling layer, and a foundation block layer. The foundation layer is formed in the order of crushed stone layer and leveling concrete layer from bottom to top, and the self-leveling layer is a layer placed on the upper surface of the foundation layer and formed by a self-leveling material. The foundation block layer is placed on the upper surface of the self-leveling layer and is a layer consisting of multiple foundation blocks. The foundation blocks include ordinary foundation blocks and perforated foundation blocks. The foundation block layer is formed by arranging multiple foundation blocks in only one row in the direction of the foundation axis, and adjacent foundation blocks are connected by installing joint materials in the joint box cutouts of each adjacent foundation block in the direction of the foundation axis. [Effects of the Invention]

[0017] The foundation block, foundation structure construction method, and foundation structure of the present invention have the following effects. (1) Compared to conventional cast-in-place concrete construction methods, the foundation structure for electrical equipment can be constructed in a significantly shorter period of time. As a result, transformers and other equipment can be put into operation quickly, meaning that consumers will be able to use electricity sooner than before. (2) Because standardized foundation blocks are used according to the standard design, there is no need to perform design calculations each time. As a result, defects due to design errors can be avoided, and costs such as labor costs associated with design can be reduced. (3) Conventional cast-in-place concrete construction methods are affected by weather conditions, such as the need to avoid construction in rainy weather and the need for considerable measures in situations like cold or hot weather. In contrast, the present invention allows construction to be carried out without being affected by weather conditions. [Brief explanation of the drawing]

[0018] [Figure 1] A perspective view showing a transformer supported by the basic structure of the present invention. [Figure 2] A schematic side view showing the basic structure of the present invention. [Figure 3] A plan view schematically showing the basic structure of the present invention. [Figure 4] (a) is a plan view schematically showing a normal foundation block among the foundation blocks, and (b) is a side view schematically showing a normal foundation block among the foundation blocks. [Figure 5] (a) is a plan view schematically showing a perforated foundation block among the foundation blocks, and (b) is a cross-sectional view schematically showing a perforated foundation block among the foundation blocks. [Figure 6] (a) is a cross-sectional view schematically showing a leg anchor with a locking plate accommodated in an anchor accommodation hole, and (b) is a cross-sectional view schematically showing a J-shaped leg anchor accommodated in an anchor accommodation hole. [Figure 7] (a) is a plan view schematically showing a pile cap foundation block among the foundation blocks, and (b) is a cross-sectional view schematically showing a pile cap foundation block among the foundation blocks. [Figure 8] A cross-sectional view schematically showing the head of a foundation pile accommodated in a pile head accommodation hole. [Figure 9] A model diagram schematically showing an example of a standard foundation determination table. [Figure 10] A model diagram schematically showing an example of a standard foundation determination table created for each electrical facility having different standards. [Figure 11] A model diagram schematically showing an example of a standard foundation determination table created for each different transformer having the same primary voltage. [Figure 12] A model diagram schematically showing an example of a foundation block arrangement table. [Figure 13] A flow chart showing the flow of main steps of a foundation structure construction method based on a spread foundation type. [Figure 14] A flow chart showing the flow of main steps of a foundation structure construction method based on a pile foundation type. MODE FOR CARRYING OUT THE INVENTION

[0019] An example of the foundation block, foundation structure construction method, and embodiment of the foundation structure of the present invention will be described with reference to the figures. Although the present invention can be used to support various electrical equipment, for convenience, an example of supporting a transformer will be described here.

[0020] 1.Overview Figure 1 is a schematic diagram illustrating the outline of the present invention, and is a perspective view showing a transformer TR supported by the base structure 200 of the present invention. As shown in this figure, the base structure 200 of the present invention is a slab-like structure that prevents the transformer TR from sinking and firmly supports the transformer TR so that it does not tip over or slide.

[0021] 2.Fundamental structure The basic structure 200 of the present invention will be described in detail with reference to the diagram. Since the basic block of the present invention constitutes the basic structure 200, the basic block will also be described while describing the basic structure 200. Furthermore, since the method for constructing the basic structure of the present invention is a method for constructing the basic structure 200 of the present invention, the basic structure 200 and the basic block of the present invention will be described first, and then the method for constructing the basic structure of the present invention will be described in detail.

[0022] Figure 2 is a side view of the foundation structure 200 of the present invention, and Figure 3 is a top view of the foundation structure 200 of the present invention. As shown in Figure 2, the foundation structure 200 of the present invention consists of multiple layers, namely a structure stacked in the order of foundation layer 230, self-leveling layer 220, and foundation block layer 210 from bottom to top. Of these, the foundation layer 230 is composed of two layers: a lower crushed stone layer 232 and an upper leveling concrete layer 231.

[0023] The self-leveling layer 220 is a layer formed by laying a "self-leveling material." This self-leveling material has the property of becoming flat on its own and is sometimes used as a subfloor. Gypsum-based self-leveling material or cement-based self-leveling material can be used. As will be described later, a foundation block layer 210 is formed by arranging multiple foundation blocks 100, and the transformer TR is placed on this foundation block layer 210. Therefore, in order to install the transformer TR in a horizontal position, it is important that the foundation blocks 100 are arranged in a horizontal position, that is, it is important that a horizontal surface is formed in the layer below the foundation block layer 210.

[0024] Conventionally, transformers TR were placed on top of a cast-in-place concrete foundation. Therefore, in order to install the transformer TR in a horizontal position, the surface of the cast-in-place concrete had to be finished as horizontally as possible, meaning that an extremely delicate trowel finish was required. On the other hand, in the present invention, since the transformer TR is placed on a precast foundation block 100, at least the mounting surface of the transformer TR (in this case, the surface of the foundation block 100) is ensured to be flat. However, if the surface of the lower layer of the foundation block 100 (for example, the leveling concrete layer 231) is not horizontal, the foundation block 100 will be placed at an angle, and as a result, the transformer TR cannot be installed in a horizontal position. In other words, in the conventional art, great effort was made to make the mounting surface of the transformer TR horizontal, but in the present invention, it is necessary to devise a way to make the mounting surface of the foundation block 100 horizontal. Therefore, the inventors of the present invention focused on a self-leveling material as the base for the foundation block layer 210. Using self-leveling material significantly reduces labor and time, as it automatically levels surfaces, eliminating the need for surface finishing, while also allowing for the creation of highly accurate horizontal surfaces.

[0025] The foundation block layer 210 is formed by arranging and connecting the foundation blocks 100 of the present invention, as shown in Figures 2 and 3. However, the foundation structure 200 is constructed by arranging multiple (five in the figures) foundation blocks 100 in only one row. For convenience, the direction in which the foundation blocks 100 are arranged (left and right in the figures) will be referred to as the "foundation axis direction," and the horizontal direction perpendicular to the foundation axis (up and down in the figures) will be referred to as the "direction perpendicular to the foundation axis."

[0026] The foundation block 100 of the present invention is a precast concrete product manufactured in advance at a factory or the like, and can be installed immediately after being transported to the site. Furthermore, the foundation block 100 is a "set of blocks" that includes at least a standard foundation block 100N and a perforated foundation block 100H, and can also be made into a set of three types including a pile head foundation block 100P. For example, in Figure 3, perforated foundation blocks 100H are placed at both ends, and three standard foundation blocks 100N are placed in between. The following describes each type of foundation block 100.

[0027] Figure 4 is a schematic diagram of a standard foundation block 100N among the foundation blocks 100, where (a) is a plan view seen from above and (b) is a side view seen in the direction of the foundation axis. As shown in this figure, the standard foundation block 100N is composed of a concrete structural body 110 and multiple (six in the figure) joint box cutouts 130. The concrete structural body 110 is made of concrete and has a roughly rectangular shape in plan view. However, when arranged as a foundation block layer 210, it is arranged so that its short side is in the direction of the foundation axis and its long side is perpendicular to the foundation axis.

[0028] The joint box cutout 130 is a box cutout formed on the side perpendicular to the foundation axis (i.e., the longitudinal direction in Figure 4), and is a space for installing the joint material 140 (Figure 2). By installing the joint material 140 in the joint box cutout 130, a joint section 211 is formed, thereby connecting adjacent foundation blocks 100 in the foundation axis direction. Specifically, as shown in Figure 2, a predetermined space is formed by the joint box cutouts 130 on both sides of the facing foundation blocks 100, and by installing the joint material 140 in that space, a joint section 211 is formed, connecting adjacent foundation blocks 100 in the foundation axis direction (left and right in the figure). For this joint section 211, the so-called "cotter joint" method disclosed in "Japanese Patent Application Publication No. 2001-214694" can be used. Of course, as long as adjacent foundation blocks 100 can be connected, various conventional methods can be adopted, not limited to cotter joints.

[0029] In the standard foundation block 100N shown in Figure 4, three joint box cutouts 130 are formed on each of the two opposing sides (left and right sides in the figure) in the direction of the foundation axis. However, joint box cutouts 130 can be formed on only one of the sides, and the number of joint box cutouts 130 to be formed can be designed arbitrarily. Furthermore, box cutouts can be formed on the underside of the standard foundation block 100N to accommodate reinforcing bars (so-called "inserted bars") installed in the self-leveling layer 220.

[0030] Figure 5 is a schematic diagram of a perforated foundation block 100H among the foundation blocks 100, where (a) is a plan view seen from above, and (b) is a cross-sectional view (in the direction of arrow AA) taken from a plane perpendicular to the foundation axis. As shown in this figure, the perforated foundation block 100H is composed of a concrete body section 110, multiple (three in the figure) joint box cutouts 130, and anchor housing holes 120. Of these, the concrete body section 110 and the joint box cutouts 130 are the same as those of the ordinary foundation block 100N.

[0031] The anchor housing hole 120 is a hole (for example, a through hole) provided in the concrete structure 110, as shown in Figure 5(b). Typically, transformers TR are equipped with various leg anchors AC, such as the leg anchor AC with a locking plate shown in Figure 6(a), or the "J-shaped" leg anchor AC shown in Figure 6(b). The anchor housing hole 120 is used as a space to accommodate these leg anchors AC. That is, when the transformer TR is placed on the foundation block layer 210, the leg anchors AC are positioned to be housed in the anchor housing hole 120, and a filler material such as non-shrink mortar is filled into the anchor housing hole 120 where the leg anchors AC are housed. This ensures that the transformer TR is supported not only vertically but also horizontally by the foundation block layer 210, which is advantageous.

[0032] In the perforated foundation block 100H shown in Figure 5, two anchor housing holes 120 are formed, but the number can be designed arbitrarily. Also, in this figure, three joint box cutouts 130 are formed on one side facing the foundation axis direction (the right side in the figure), but joint box cutouts 130 can also be formed on both sides facing the foundation axis direction (the left and right sides in the figure), and the number of joint box cutouts 130 to be formed can also be designed arbitrarily. Furthermore, on the lower side of the perforated foundation block 100H, box cutouts can be formed to accommodate reinforcing bars (so-called "inserted bars") installed in the self-leveling layer 220, similar to the ordinary foundation block 100N.

[0033] Figure 7 is a schematic diagram of the pile head foundation block 100P of the foundation block 100, where (a) is a plan view seen from above, and (b) is a cross-sectional view (in the direction of arrow BB) taken from a plane perpendicular to the foundation axis. As shown in this figure, the pile head foundation block 100P is composed of a concrete body section 110, a plurality (six in the figure) of joint box cutouts 130, and a pile head housing hole 150. Of these, the concrete body section 110 and the joint box cutouts 130 are the same as those of the ordinary foundation block 100N.

[0034] As shown in Figure 7(b), the pile head accommodating hole 150 is a through-hole that penetrates the concrete structure 110 in the direction of its thickness and is provided within the concrete structure 110. If the ground on which the foundation block 100 is to be installed is compacted sandy soil, cohesive soil with high cohesion, or bedrock, then a "direct foundation" type can be used, in which ordinary foundation blocks 100N or perforated foundation blocks 100H are simply placed on the ground. On the other hand, in places where the supporting layer is located at a considerably deep position, ground improvement will be carried out or a "pile foundation" type will be adopted. The pile head accommodating hole 150 is then used as a space to accommodate the head of the foundation pile PL, as shown in Figure 8. That is, when the pile head foundation block 100P is placed after the foundation pile PL has been installed, it is positioned so that the head of the foundation pile PL is accommodated within the pile head accommodating hole 150, and then a filler material such as non-shrink mortar is filled into the pile head accommodating hole 150 where the head of the foundation pile PL is accommodated. As a result, the foundation block layer 210, including the pile head foundation block 100P, is supported not only vertically but also horizontally by the foundation pile PL, which is preferable.

[0035] In the pile head foundation block 100P shown in Figure 5, two pile head accommodating holes 150 are formed, but the number can be designed arbitrarily. Also, in this figure, three joint box cutouts 130 are formed on each of the two opposing sides (left and right sides in the figure) in the direction of the foundation axis, but joint box cutouts 130 can be formed on only one of the sides, and the number of joint box cutouts 130 to be formed can also be designed arbitrarily.

[0036] By the way, the dimensions of the foundation blocks 100 of the present invention, such as the ordinary foundation block 100N, the perforated foundation block 100H, and the pile head foundation block 100P, can be infinitely varied (especially in the direction of the foundation axis) depending on the dimensions of the foundation of a transformer or the like to which the foundation blocks are connected (hereinafter referred to as the overall foundation) and the number of divisions of the overall foundation. However, when actually selecting a foundation block, a wide range of choices makes it difficult to select a foundation block with the optimal dimensions, and also increases management and manufacturing costs. Therefore, it is desirable to use only a finite number of foundation blocks 100 that can be selected (for example, two types), or in other words, it is desirable to standardize the foundation blocks.

[0037] The dimensions of the overall foundation are determined by designing the specifications of the transformer TR to be constructed (hereinafter referred to as "electrical equipment specifications"), the physical properties of the supporting ground (hereinafter simply referred to as "ground physical properties"), and the "design horizontal seismic intensity" set for each region. The foundation must also satisfy all the allowable values ​​for support, overturning, and sliding of the transformer TR (hereinafter referred to as "judgment conditions"). An overall foundation that covers a considerable range of ground physical properties and design horizontal depth and satisfies the judgment conditions is defined as the standard foundation, and its dimensions are adopted as the standard foundation dimensions. The electrical equipment specifications include at least the weight and center of gravity of the transformer TR, and the ground physical properties include the N value obtained from the standard penetration test, cohesion c, internal friction angle φ, and unit weight γ. By dividing the standard foundation into a fixed number of equal parts along the foundation axis, it becomes possible to standardize the dimensions of the foundation blocks. For example, if there are two types of standard foundation dimensions, "short side 2,600mm x long side 5,000mm x slab thickness 600mm" (e.g., standard foundation type A) and "short side 3,000mm x long side 5,000mm x slab thickness 600mm" (e.g., standard foundation type B), then dividing these into five sections perpendicular to the foundation axis results in two types of standard dimensions for foundation block 100: "2,600mm x 1,000mm x 600mm" (hereinafter referred to as standard A) and "3,000mm x 1,000mm x 600mm" (hereinafter referred to as standard B).

[0038] As mentioned above, the standard foundation satisfies the judgment criteria under design conditions that cover a considerable range of ground physical properties and design horizontal depth. Therefore, the range in which the standard foundation can be adopted (i.e., the "adoptable range" that satisfies the judgment criteria) and the range in which the standard foundation cannot be adopted (i.e., the "non-adoptable range" that does not satisfy the judgment criteria) are known in advance. Thus, the table that organizes the adoptable and non-adoptable ranges is the "Standard Foundation Judgment Table" shown in Figure 9. As shown in this figure, the standard foundation judgment table uses the design horizontal seismic intensity on the horizontal axis and the N value (ground physical property value) on the vertical axis, and further divides each into predetermined ranges to create a mesh of the design horizontal seismic intensity and N value ranges, and then indicates whether it can be adopted ("OK" in the figure) or not ("NG" in the figure) for each mesh. This makes it possible to see at a glance which "adoptable ranges" the foundation block 100 can be used in and which "non-adoptable ranges" it cannot be used in.

[0039] Figure 10 shows another pattern of the standard foundation judgment table. For example, the upper part of Figure 10 shows whether standard foundation types A, B, and C can be used for a 66kV transformer. Also, similar to Figure 9, the horizontal and vertical axes of the standard foundation judgment table use the design horizontal seismic intensity on the vertical axis and the N-value (ground physical property value) on the vertical axis, allowing for a quick determination of whether or not to use a standard foundation based on differences in transformer foundation capacity and design conditions. The lower part of Figure 10 shows the suitability of each standard foundation type for a 154kV transformer, similar to the upper part of Figure 10. Thus, a separate standard foundation judgment table is created for each standard foundation type, and also for electrical equipment with different specifications (for 66kV transformers and 154kV transformers).

[0040] Even if electrical equipment specifications such as transformers (TR) are the same, if the manufacturers are different, the electrical equipment specifications (weight and center of gravity) will naturally differ. For example, even with the same 66kV transformer, the electrical equipment specifications of manufacturer X and manufacturer Y may differ, meaning that standard foundation type A may be applicable to manufacturer X's transformer but not to manufacturer Y's. Therefore, the adoption or non-adoption of a standard foundation must be considered on a case-by-case basis, depending on the manufacturer and model number. Figure 11 summarizes 66kV transformers by manufacturer. This allows for a quick determination of whether a manufacturer's standard foundation can be adopted for each transformer capacity. Thus, a standard foundation determination table is created separately for each electrical equipment specification of the target electrical equipment.

[0041] The decision on whether to adopt a standard foundation is made using the standard foundation determination tables in Figures 9-11, either alone or in combination. First, the capacity of the transformer to be installed is determined, and Figure 10 is used to make a preliminary judgment on the feasibility of adopting a standard foundation. After that, the manufacturer or model number is determined, and Figure 11 is used to determine whether or not to adopt a standard foundation and which standard foundation type to adopt. Once the standard foundation type is determined, the specifications and number of foundation blocks that make up the standard foundation are determined, and the order in which the ordinary foundation blocks 100N, perforated foundation blocks 100H, and pile head foundation blocks 100P are arranged (hereinafter referred to as "block arrangement") is planned. At this time, it is necessary to select a foundation block 100 that corresponds to the shape and dimensions of the transformer TR and the specifications including the position of the leg anchor AC (hereinafter referred to as "electrical equipment shape"), and more specifically, it is necessary to select a foundation block 100 that has anchor housing holes 120 suitable for the position and size of the leg anchor AC related to the transformer TR. Similarly, it is necessary to select a pile head foundation block 100P corresponding to the planned foundation pile PL, and more specifically, to select a pile head foundation block 100P equipped with a pile head receiving hole 150 suitable for the position and size of the foundation pile PL. Therefore, it is advisable to pre-determine the number of foundation blocks 100 to be used and their arrangement for each type of transformer TR.

[0042] Figure 12 is a model diagram showing an example of a quick reference table (hereinafter referred to as the "foundation block arrangement table") that shows the correspondence between the type of transformer TR, the number of foundation blocks 100 used, and the block arrangement. As shown in this figure, a foundation block arrangement table is created for each type of transformer TR (in the figure, a combination of primary voltage and manufacturer) and for each type of standard foundation (in the figure, standard foundation type A to standard foundation type C), showing the number of foundation blocks 100 used and the block arrangement. Therefore, once the type of transformer TR and the standard foundation to be adopted are determined, the number of foundation blocks 100 used and the block arrangement corresponding to the type of transformer TR can be grasped at a glance by referring to the foundation block arrangement table related to that transformer TR and standard foundation.

[0043] 3.Foundation structure construction method Next, the method for constructing the foundation structure of the present invention will be explained in detail with reference to the diagram. Note that the method for constructing the foundation structure of the present invention is the method for constructing the foundation structure 200 described so far. Therefore, explanations that overlap with those described for the foundation structure 200 and foundation block 100 will be avoided, and the explanation will mainly focus on the aspects specific to the method for constructing the foundation structure of the present invention. In other words, anything not described here is the same as what is described in "2. Foundation Structure".

[0044] As previously described, if the ground on which the foundation block 100 is to be installed is compacted sandy soil, cohesive soil with high cohesion, or bedrock, then a "direct foundation" type can be used, in which the ordinary foundation block 100N or perforated foundation block 100H is simply placed on the ground. On the other hand, in places where the supporting layer is located at a considerably deep position, a "pile foundation" type may be adopted. Therefore, the foundation structure construction method of the present invention can be broadly divided into the direct foundation type and the pile foundation type. Accordingly, we will explain the foundation structure construction method for each of the direct foundation type and the pile foundation type separately.

[0045] Figure 13 is a flowchart showing the main steps in the construction method of a foundation structure using a direct foundation type. As shown in this figure, when constructing a foundation structure 200 using foundation blocks 100, first the specifications and manufacturer of the transformer TR to be adopted are determined, and the overall shape and dimensions (especially the planar dimensions) of the foundation structure 200 on which the transformer TR will be placed are planned, and then the foundation blocks 100 to be used are selected (Step 311 in Figure 13). Specifically, the "ground physical properties" and "design horizontal seismic intensity" of the site where the transformer TR is to be installed are determined. At this time, the ground physical properties can be determined by actually conducting boring surveys or standard penetration tests, or if there are test results from the surrounding area that have already been obtained, those can be used. Then, a standard foundation judgment table is selected based on the specifications of the transformer TR to be installed (or the electrical equipment specifications including the manufacturer), and the appropriate type of foundation block 100 is selected by comparing the ground physical properties and design horizontal seismic intensity with that standard foundation judgment table. Of course, the appropriate number of foundation blocks to be used can also be planned according to site conditions such as the delivery route and construction space.

[0046] Once the foundation block 100 to be adopted is determined, the "number of blocks to be used" and the "block arrangement" of the foundation block 100 to be used to construct the foundation block layer 210 are planned (Step 312 in Figure 13). At this time, a foundation block arrangement table can be used, or the plan can be made as appropriate according to the site conditions without using this table.

[0047] Once the number of foundation blocks 100 to be used and their placement are planned, the actual work at the site begins. Specifically, the foundation layer 230 is formed by first excavating the surface layer of the ground, laying crushed stone to form a crushed stone layer 232, and laying leveling concrete to form a leveling concrete layer 231 (Step 313 in Figure 13). Once the foundation layer 230 is formed, a self-leveling layer 220 is formed by laying gypsum-based self-leveling material or cement-based self-leveling material on the upper surface of the foundation layer 230 (Step 314 in Figure 13). Then, the ordinary foundation blocks 100N and perforated foundation blocks 100H are laid on the upper surface of the self-leveling layer 220 according to the planned number of blocks to be used and their placement (Step 315 in Figure 13). At this time, as previously described, only one row of ordinary foundation blocks 100N and perforated foundation blocks 100H is laid in the direction of the foundation axis.

[0048] When the standard foundation blocks 100N and perforated foundation blocks 100H are placed side by side as planned, a joint material 140 is installed in the space formed by the joint box cutout 130 of adjacent foundation blocks 100 in the foundation axis direction, thereby connecting the adjacent foundation blocks 100 (Step 316 in Figure 13). Then, the transformer TR is placed on the foundation block layer 210 so that the leg anchors AC are housed in the anchor housing holes 120, and the transformer TR is firmly supported in the foundation block layer 210 by filling the anchor housing holes 120 in which the leg anchors AC are housed with a filler material such as non-shrink mortar.

[0049] Figure 14 is a flowchart showing the main steps in the construction method of a foundation structure using a pile foundation. Similar to the direct foundation method, the construction method of a foundation structure using a pile foundation method first involves selecting the foundation blocks 100 to be used (Step 321 in Figure 14), and then planning the number of foundation blocks 100 to be used and their arrangement (Step 322 in Figure 14). However, in this case, the arrangement of blocks includes ordinary foundation blocks 100N, perforated foundation blocks 100H, and pile head foundation blocks 100P.

[0050] Once the number of foundation blocks (100) to be used and their placement are planned, on-site work begins. Specifically, similar to direct foundations, the ground surface is first excavated, and foundation piles (PL) are installed so that the pile heads protrude to a certain extent (Step 323 in Figure 14). When installing the foundation piles (PL), the appropriate method can be selected depending on the ground conditions, such as the press-in method or the rotary impact method.

[0051] After installing the foundation pile PL, a foundation layer 230 is formed (Step 324 in Figure 14), and then a self-leveling layer 220 is formed on the upper surface of the foundation layer 230 (Step 325 in Figure 14). Then, ordinary foundation blocks 100N, perforated foundation blocks 100H, and pile head foundation blocks 100P are arranged on the upper surface of the self-leveling layer 220 in the planned number and block arrangement (Step 326 in Figure 14). At this time, the pile head foundation blocks 100P are positioned so that the heads of the foundation pile PL are housed within the pile head housing holes 150. Next, the foundation block layer 210, including the pile head foundation blocks 100P, and the foundation pile PL are connected by filling the pile head housing holes 150, in which the heads of the foundation pile PL are housed, with a filler material such as non-shrink mortar (Step 327 in Figure 14).

[0052] As planned, the standard foundation blocks 100N, perforated foundation blocks 100H, and pile head foundation blocks 100P are arranged in a line, and adjacent foundation blocks 100 are connected to each other using jointing material 140 (Step 328 in Figure 14). Then, the transformer TR is placed on the foundation block layer 210 so that the leg anchors AC are housed in the anchor housing holes 120, and the transformer TR is firmly supported on the foundation block layer 210 by filling the anchor housing holes 120 in which the leg anchors AC are housed with a filler material such as non-shrink mortar. [Industrial applicability]

[0053] The foundation block, foundation structure construction method, and foundation structure of the present invention can be used to support transformers and various other electrical equipment. According to the present invention, transformers can be put into operation quickly, and as a result, consumers can utilize electricity sooner. Therefore, this invention is not only industrially applicable but also has the potential to make a significant contribution to society. [Explanation of Symbols]

[0054] 100 Basic block of the present invention 100N (of the foundation blocks) Standard foundation block 100H (of the foundation blocks) Perforated foundation block 100P (of the foundation blocks) Pile head foundation block 110 Concrete structure (of the foundation block) 120 (Anchor housing holes in perforated foundation blocks) 130 (Foundation block) Joint box removal section 140 (Foundation block) Joint material 150 (Pile head foundation block) Pile head accommodating hole 200 Basic structure of the present invention 210 (Foundation block layer of foundation structure) 211 Joint section (of the foundation block layer) 220 Self-leveling layer (of the foundation structure) 230 (Foundation layer of the foundation structure) 231 (Leveling concrete layer of the foundation) 232 (Crushed stone layer of the foundation layer) AC Leg Anchor PL foundation pile TR transformer

Claims

1. A precast foundation block that constitutes the foundation structure of electrical equipment, Including ordinary foundation blocks and perforated foundation blocks, The aforementioned ordinary foundation block has a concrete frame portion that is roughly rectangular in plan view, with the foundation axis direction of the foundation structure being the shorter direction and the direction perpendicular to the foundation axis of the foundation structure being the longer direction, and a joint box cutout portion formed on the surface perpendicular to the foundation axis. The perforated foundation block comprises the concrete body portion, the joint box cutout portion, and the anchor housing hole provided within the concrete body portion. The foundation structure is formed by arranging the ordinary foundation block and the perforated foundation block in a single row along the foundation axis, and then installing a joint material in the joint box cutout. The electrical equipment can be supported by placing it on the foundation structure such that its leg anchors are accommodated in the anchor housing holes, and then filling the anchor housing holes with filler material. A foundation block characterized by the following features.

2. A method for constructing the foundation structure of electrical equipment using multiple precast foundation blocks, The aforementioned foundation blocks include ordinary foundation blocks and perforated foundation blocks. The aforementioned ordinary foundation block has a concrete frame portion that is roughly rectangular in plan view, with the foundation axis direction of the foundation structure being the shorter direction and the direction perpendicular to the foundation axis of the foundation structure being the longer direction, and a joint box cutout portion formed on the surface perpendicular to the foundation axis. The perforated foundation block comprises the concrete body portion, the joint box cutout portion, and the anchor housing hole provided within the concrete body portion. The foundation layer formation process involves forming a foundation layer on the ground in the order of crushed stone layer and leveling concrete layer from the bottom up, A level layer formation step is performed by laying a self-leveling material on the upper surface of the aforementioned base layer to form a self-leveling layer, A foundation block placement step involves arranging a plurality of foundation blocks in a single row along the foundation axis direction on the upper surface of the self-leveling layer, The process includes a foundation block connecting step, in which a connecting material is installed in the joint box cutout of each of the foundation blocks adjacent to each other in the foundation axis direction, thereby connecting adjacent foundation blocks. The electrical equipment can be supported by placing it on the foundation structure such that its leg anchors are accommodated in the anchor housing holes, and then filling the anchor housing holes with filler material. A method for constructing a foundation structure characterized by the following features.

3. Two or more types of the aforementioned foundation structure with different planar dimensions are set in advance as standard foundations, and two or more types of the aforementioned foundation blocks are provided by dividing the standard foundation in the direction of the foundation axis. The system further includes a foundation block selection step, in which one foundation block is selected from two or more types of foundation blocks using a pre-created standard foundation determination table. The aforementioned standard foundation determination table is created for each electrical equipment with different specifications, and also for each type of standard foundation. Furthermore, the standard foundation determination table indicates the suitability of adopting the standard foundation of that type, based on the ground properties and the design horizontal seismic intensity set for each region. In the foundation block selection process, the standard foundation determination table relating to the specifications of the electrical equipment to be used is used, and the foundation block relating to the standard foundation determination table relating to each type of standard foundation is selected by comparing the design horizontal seismic intensity corresponding to the construction site of the foundation structure and the ground physical properties at the construction site. In the aforementioned foundation block placement step, the foundation blocks of the type selected in the aforementioned foundation block selection step are placed. The method for constructing a foundation structure according to claim 2, characterized by its features.

4. The aforementioned standard basic judgment table is created for each piece of electrical equipment that has the same standard but different electrical equipment specifications. The specifications for the electrical equipment include the weight and center of gravity of the electrical equipment. In the foundation block selection process, one foundation block is selected by comparing the standard foundation determination table relating to the electrical equipment specifications of the target electrical equipment with the design horizontal seismic intensity and the ground physical properties. The method for constructing a foundation structure according to claim 3, characterized by its features.

5. The system further includes a foundation block arrangement planning step, which involves planning the number of foundation blocks to be used and the arrangement of the ordinary foundation blocks and the perforated foundation blocks using a pre-created foundation block arrangement table. The aforementioned base block arrangement table is created for each type of standard base, Furthermore, the aforementioned foundation block arrangement table indicates the number of foundation blocks to be used and the arrangement of the ordinary foundation blocks and the perforated foundation blocks, according to the shape of the electrical equipment. The shape of the electrical equipment includes the planar dimensions of the electrical equipment and the position of the leg anchors. In the foundation block arrangement planning step, the foundation block arrangement table relating to the type of foundation block selected in the foundation block selection step is used, and the number of foundation blocks to be used, and the arrangement of the ordinary foundation blocks and perforated foundation blocks are planned based on the shape of the electrical equipment to be used. In the aforementioned foundation block placement step, the foundation blocks are placed in the number and arrangement planned in the aforementioned foundation block placement planning step. A method for constructing a foundation structure according to claim 3 or 4, characterized by the features described above.

6. The aforementioned foundation block includes a pile head foundation block. The pile head foundation block comprises the concrete body portion, the joint box cutout portion, and a pile head housing hole provided within the concrete body portion and penetrating the concrete body portion in the thickness direction. The process of installing foundation piles, The system further comprises a foundation pile connecting step for connecting the aforementioned foundation pile to the aforementioned pile head foundation block, In the aforementioned foundation block placement step, the pile head foundation block is positioned so that the head of the foundation pile is accommodated in the pile head receiving hole. In the aforementioned foundation pile connection process, a filler material is filled into the pile head housing hole in which the head of the foundation pile is housed. The method for constructing a foundation structure according to claim 2, characterized by its features.

7. A foundation structure that supports electrical equipment, The foundation layer is formed in the order of crushed stone layer and leveling concrete layer from the bottom, A self-leveling layer is installed on the upper surface of the aforementioned foundation layer and is formed by a self-leveling material, The system comprises a foundation block layer consisting of a plurality of foundation blocks arranged on the upper surface of the self-leveling layer, The aforementioned foundation blocks include ordinary foundation blocks and perforated foundation blocks. The aforementioned ordinary foundation block has a concrete structure that is roughly rectangular in plan view, with the foundation axis direction being the shorter direction and the direction perpendicular to the foundation axis being the longer direction, and a joint box cutout formed on the surface perpendicular to the foundation axis. The perforated foundation block comprises the concrete body portion, the joint box cutout portion, and the anchor housing hole provided within the concrete body portion. The aforementioned foundation block layer is formed by arranging a plurality of the foundation blocks in only one row in the direction of the foundation axis, Furthermore, the foundation block layer is connected to adjacent foundation blocks by installing jointing material in the joint box cutouts related to each of the foundation blocks adjacent to each other in the foundation axial direction. The electrical equipment can be supported by placing it on such a surface that its leg anchors are accommodated in the anchor housing holes, and then filling the anchor housing holes with filler material. A foundation structure characterized by the following features.

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