Building and construction method thereof

Abstract

To provide a building having a high degree of freedom in design by suppressing the limitation of the improvement of the strength of a soil cement column row wall, and its construction method.SOLUTION: In the architectural structure 100, at least a batholith 12 of an underground part 11 provided in a building 10 in a foundation G and a soil-cement column-row type continuous wall 20 provided around the building 10 are joined, the soil-cement column-row type continuous wall 20 has a steel core material 40 buried inside soil-cement 30, and the soil-cement 30 penetrates a non-support layer G1 of the foundation G and is embedded in the middle of a support layer G2 below the non-support layer inner wall. The soil-cement 30 is provided with a high-strength soil-cement 31 of relatively high strength in a lower part and a low-strength soil-cement 32 of relatively low strength in an upper part, and the high-strength soil-cement 31 is provided in a range from a midway position of the non-bearing layer G1 to the bearing layer G2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a building and a construction method thereof. [Background technology]

[0002] Retaining walls include prefabricated sheet pile walls such as horizontal sheet pile walls and steel sheet pile walls, and cast-in-place walls such as column-row walls and continuous underground walls. Column-row walls include cast-in-place reinforced concrete column-row walls, steel pipe column-row walls, and soil cement column-row walls (soil cement column-row continuous walls).

[0003] For example, while the above-mentioned soil cement diaphragm column wall is a temporary structure, there is also a form in which the soil cement diaphragm column wall is used as part of the foundation of a permanent building by being connected to the basement or the like of the underground part of the building. In this way, by using the soil cement diaphragm column wall not only as an earth retaining wall but also as part of the foundation of the permanent structure, the structure of the foundation of the permanent structure can be simplified, and for example, the amount of concrete and rebar in the foundation can be reduced, thereby enabling a significant reduction in construction costs.

[0004] Patent Document 1 proposes a building foundation structure in which a soil cement column wall is used in place of foundation piles near the perimeter of the building. The soil cement column wall has a core member buried in soil cement, which comprises multiple steel frames arranged horizontally and steel members extending horizontally that connect these steel frames on both sides of the wall, and the soil cement column wall reaches the supporting layer, which is made of high-strength soil cement. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-257743 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the building foundation structure described in Patent Document 1, by using soil cement pilaster walls as foundation piles and using high-strength soil cement for the soil cement in the support layer, it is possible to form a building foundation structure equipped with soil cement pilaster walls that are strong enough to bear the vertical load of the building. However, because the high-strength soil cement is limited to the support layer, the improvement in the bearing capacity of the soil cement pilaster walls is limited, and it can be said that this is a foundation structure with limited design freedom.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a building with a high degree of design freedom and a construction method thereof that can suppress restrictions on improving the bearing capacity of soil cement column walls. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of the building according to the present invention is as follows: A building in which at least a basement of an underground portion of a building located in the ground is joined to a soil cement continuous column wall provided around the building, and the soil cement continuous column wall has a steel core material buried inside the soil cement, The soil cement penetrates the non-bearing layer of the ground and is embedded in the middle of the bearing layer below it, The soil cement comprises a high-strength soil cement located at the bottom and having a relatively high strength, and a low-strength soil cement located at the top and having a relatively low strength, The high-strength soil cement is provided in the range from the middle of the non-supporting layer to the supporting layer.

[0009] According to this aspect, the soil cement that constitutes the soil cement columnar continuous wall, which is located within the ground and joined to at least the base of the underground part of the building, penetrates the non-bearing layer of the ground and is embedded halfway into the bearing layer below. This soil cement comprises a high-strength soil cement at the bottom that is relatively high in strength and a low-strength soil cement at the top that is relatively low in strength. Since the high-strength soil cement is provided in the range from the middle of the non-bearing layer to the bearing layer, the construction position of the high-strength soil cement is not limited to the bearing layer but extends to the middle of the non-bearing layer. Therefore, the construction range of the high-strength soil cement can be adjusted according to the required strength, which prevents restrictions on the improvement of strength and increases the design freedom.

[0010] Here, "at least the base of the building" includes not only the (underground) base of the building, but also columns (exterior columns), exterior walls, etc. Also, "midway through the non-bearing layer" refers to various depth positions in the range from the bottom surface of the base to the bearing layer when there is a non-bearing layer (including multiple types of non-bearing layers) in the range from the bottom surface of the base to the bearing layer, and the "midway through the non-bearing layer", which indicates the height position of the high-strength soil cement, is set according to the vertical bearing capacity (strength to resist the building load) required of the soil cement column-type continuous wall, etc.

[0011] Furthermore, the formation of high-strength soil cement and low-strength soil cement is determined, for example, by the volume ratio of cement to sand. High-strength soil cement can be formed by using a rich mix with a high cement ratio, while low-strength soil cement can be formed by using a lean mix with a low cement ratio. For example, low-strength soil cement has a compressive strength of 0.5 N / mm 2 The soil cement can be made with a low mix ratio when forming this soil cement. On the other hand, high strength soil cement has a compressive strength of 0.5N / mm 2 Exceeding 5N / mm 2 The soil cement can be made to have a range of the above, and the blending when forming this soil cement can be made rich blending.

[0012] Another aspect of the building according to the present invention is The core material is characterized in that a first shear connector is provided in a region corresponding to high-strength soil cement.

[0013] According to this embodiment, a first shear connector is provided in the area of ​​the core material corresponding to the high-strength soil cement, thereby forming a soil cement column-type continuous wall with high strength against both the building load (push load) and the pull-out load acting from the building.

[0014] Another aspect of the building according to the present invention is The first shear connector is a headed stud.

[0015] According to this aspect, the first shear connector is a headed stud, which makes it possible to increase bearing pressure resistance while minimizing manufacturing costs.

[0016] Another aspect of the building according to the present invention is The first shear connector is characterized by comprising a perforated steel plate and a frame-shaped protrusion provided around the hole on the wide surface of the perforated steel plate.

[0017] According to this aspect, the first shear connector comprises a perforated steel plate and a frame-shaped protrusion provided around the hole on the wide surface thereof, thereby making it possible to obtain high bearing resistance with a small bearing area, and the small bearing area can improve the ease of erecting the core material.

[0018] In another aspect of the building according to the present invention, A plurality of columns are joined to the base of the building at intervals in the circumferential direction in a plan view, and the building load is transmitted to the base via the plurality of columns, The soil cement diaphragm wall comprises a load-bearing wall that supports the building load transmitted from the base plate and a non-load-bearing wall that does not support the building load, At least, the soil cement forming the load-bearing wall is embedded in the middle of the support layer, and the soil cement comprises the high-strength soil cement and the low-strength soil cement.

[0019] According to this aspect, the soil cement columnar continuous wall comprises a load-bearing wall that supports the building load transmitted from the base plate and a non-load-bearing wall that does not support the building load, and the soil cement that forms at least the load-bearing wall is embedded halfway through the supporting layer, and the soil cement comprises high-strength soil cement and low-strength soil cement, thereby realizing economical construction of the soil cement columnar continuous wall as a whole while forming a high-strength load-bearing wall in part of it.

[0020] Here, "at least the soil cement forming the load-bearing wall is embedded halfway through the supporting layer" means that it includes both a configuration in which only the load-bearing wall is embedded halfway through the supporting layer, and a configuration in which both the load-bearing wall and the non-load-bearing wall are embedded halfway through the supporting layer.

[0021] The load-bearing wall is a soil cement diaphragm wall in an area corresponding to the columns erected from the base of the building. Alternatively, if the building load acts from the columns to the base and spreads at a predetermined gradient (for example, 45 degrees) toward the underside of the base and is transmitted below the base, the load-bearing wall may be a soil cement diaphragm wall in an area where the building load spreads at this base.

[0022] Since the non-load-bearing walls between the load-bearing walls corresponding to the columns erected at intervals do not support the building load, they may, for example, be embedded at a position midway through the non-bearing layer, and only low-strength soil cement may be used for the soil cement that is formed.In this way, by changing the length of the load-bearing and non-load-bearing walls and the material (mixture) of the soil cement, it is possible to form an economical, high-strength soil cement column-type continuous wall.

[0023] In addition, one aspect of the construction method for a building according to the present invention is as follows: A construction method for a building in which at least a basement of an underground portion of a building located in the ground is joined to a soil cement diaphragm wall provided around the building, Process A involves constructing a soil cement column-type continuous wall by placing soil cement in the ground and erecting a steel core material inside the soil cement; Step B: cutting the soil cement at the upper end of the soil cement diaphragm wall to expose a portion of the core material and joining a second shear connector to the exposed portion; and step C of joining the base plate and the soil cement columnar continuous wall by embedding the second shear connector in the base plate, In the step A, The soil cement penetrates the non-bearing layer of the ground and is embedded halfway into the bearing layer below, with relatively low-strength low-strength soil cement being placed above and relatively high-strength high-strength soil cement being placed below, and the high-strength soil cement being placed in the range from the midpoint of the non-bearing layer to the bearing layer.

[0024] According to this aspect, the soil cement that constitutes the soil cement columnar continuous wall, which is located within the ground and joins to at least the base slab of the underground portion of the building, penetrates the non-bearing layer of the ground and is embedded halfway into the bearing layer below it, and at this time, relatively low-strength low-strength soil cement is placed above, and relatively high-strength high-strength soil cement is placed below, and the high-strength soil cement is placed in the range from the middle of the non-bearing layer to the bearing layer.As a result, the placement position of the high-strength soil cement is not limited to the bearing layer but extends to the middle of the non-bearing layer, and therefore the bearing strength of the soil cement columnar wall can be changed by adjusting the placement range of the high-strength soil cement, which makes it possible to prevent restrictions on the improvement of bearing strength and increases the degree of freedom in design.

[0025] Another aspect of the construction method for a building according to the present invention is as follows: In the step A, When the diameter of the soil cement is d, The construction switching level between the high-strength soil cement and the low-strength soil cement is set at a position 3d and 2m or more above the design switching level.

[0026] According to this embodiment, by setting the construction switching level between high-strength soil cement and low-strength soil cement at a position 3d and 2m or more above the design switching level, it is possible to prevent low-strength soil cement from being mixed into areas where high-strength soil cement is required.

[0027] Another aspect of the construction method for a building according to the present invention is as follows: In the step A, The construction is characterized in that a retarder is added to the high-strength soil cement.

[0028] According to this embodiment, by applying a retarder when constructing high-strength soil cement, for example, which has a rich cement content and therefore accelerates hardening, good workability can be ensured when constructing a core material into the high-strength soil cement.

[0029] In another aspect of the construction method for a building according to the present invention, A plurality of columns are joined to the base of the building at intervals in the circumferential direction in a plan view, The soil cement diaphragm wall comprises a load-bearing wall that supports the building load transmitted from the base plate and a non-load-bearing wall that does not support the building load, In the step A, The soil cement forming the load-bearing wall is formed by applying the low-strength soil cement and the high-strength soil cement, The soil cement forming the non-load bearing wall is formed by applying the low strength soil cement.

[0030] According to this aspect, the soil cement columnar continuous wall comprises a load-bearing wall that supports the building load transmitted from the base slab and a non-load-bearing wall that does not support the building load, and the soil cement that forms the load-bearing wall is formed by applying low-strength soil cement and high-strength soil cement, and the soil cement that forms the non-load-bearing wall is formed by applying low-strength soil cement, thereby realizing economical construction of the soil cement columnar continuous wall as a whole while constructing a high-strength load-bearing wall in part of it.

[0031] In another aspect of the construction method for a building according to the present invention, The soil cement diaphragm wall comprises alternating load-bearing walls and non-load-bearing walls around the periphery of the building; In the step A, The non-load-bearing walls are constructed first, and then the load-bearing walls are constructed between the non-load-bearing walls that have already been constructed.

[0032] According to this aspect, in a configuration in which a soil cement column-type continuous wall has load-bearing walls and non-load-bearing walls alternating around a building, by constructing the non-load-bearing walls first and then constructing the load-bearing walls between the non-load-bearing walls that have already been constructed, it is possible to prevent high-strength soil cement from entering the area where the non-load-bearing walls are to be formed, and to construct the load-bearing walls and non-load-bearing walls in the areas where they should be formed, respectively. [Effects of the Invention]

[0033] As can be understood from the above explanation, the building and construction method of the present invention can prevent restrictions on improving the bearing capacity of the soil cement column wall, and can provide a building and construction method with a high degree of design freedom. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a vertical cross-sectional view of an example of a building according to an embodiment. [Figure 2] FIG. 2 is a view taken along the line II-II in FIG. [Figure 3]FIG. 10 is a vertical cross-sectional view of another example of a building according to an embodiment. [Figure 4] FIG. 4 is a view taken along the line IV-IV in FIG. 3. [Figure 5] FIG. 1 is a perspective view of an example of a first shear connector. [Figure 6] FIG. 1 is a diagram showing an example of a construction cycle for low-strength soil cement and high-strength soil cement. [Figure 7] FIG. 1 is a diagram showing an example of the construction sequence of a soil cement diaphragm wall in the circumferential direction of a building. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, a building and a construction method thereof according to an embodiment will be described with reference to the accompanying drawings. In this specification and drawings, substantially identical components are designated by the same reference numerals, and redundant explanations may be omitted.

[0036] [Building according to the embodiment and its construction method] An example of a building according to an embodiment and a construction method thereof will be described with reference to Fig. 1 to Fig. 7. Fig. 1 is a longitudinal cross-sectional view of an example of a building according to an embodiment, and Fig. 2 is a view taken along arrows II-II in Fig. 1. Fig. 3 is a longitudinal cross-sectional view of another example of a building according to an embodiment, Fig. 4 is a view taken along arrows IV-IV in Fig. 3, and Fig. 5 is a perspective view of an example of a first shear connector. Fig. 6 is a diagram showing an example of a construction cycle for low-strength soil cement and high-strength soil cement, and Fig. 7 is a diagram showing an example of the construction sequence of a soil cement diaphragm wall in the circumferential direction of a building.

[0037] The building 100 shown in Fig. 1 is constructed by joining a base 12 of the underground section 11 of a building 10 located in the ground G to a soil cement diaphragm column wall 20 constructed around the periphery of the building 10. For example, a soil cement diaphragm column wall 20 having a rectangular frame shape in plan view is constructed around the base 12 of the underground section 11 of a building 10 that is rectangular in plan view, and the two are joined at multiple locations. Note that the shape of the building 10 in plan view is diverse, and the soil cement diaphragm column wall 20 is constructed in a frame shape that corresponds to the shape of the building 10 in plan view.

[0038] 7, a plurality of outer columns 13 are erected at intervals in the circumferential direction of the base 12 of the basement 11 of the building 10 in a plan view, and a load-bearing wall 20A (one example of a soil cement diaphragm wall 20) is constructed in the area corresponding to each outer column 13, while a non-load-bearing wall 20B (another example of a soil cement diaphragm wall 20) is constructed in the other area. The load-bearing wall 20A has a constituent soil cement 30 that includes high-strength soil cement 31 and low-strength soil cement 32, while the soil cement 30 that constitutes the non-load-bearing wall 20B includes only low-strength soil cement 32.

[0039] The building 10 may be made of RC (Reinforced Concrete), S (Steel), SRC (Steel Reinforced Concrete), or a hybrid of these structures, and includes a variety of types of buildings, such as office buildings, apartment buildings, gymnasiums, shopping malls, and various public buildings. In the illustrated example below, the building will be described as having at least the basement 12 of the basement 11 made of reinforced concrete.

[0040] On the other hand, the soil cement continuous column wall 20 is constructed so that portions of the soil cement 30, which are circular in plan view, overlap each other, and a core material 40 made of H-shaped steel is buried inside the soil cement 30 in the circular drilled hole Ga in plan view. Here, in addition to H-shaped steel, I-shaped steel, steel sheet piles, secondary concrete products, etc. may also be used as the core material.

[0041] The soil cement 30 is produced by mixing and stirring the earth and sand generated by excavating the ground G with cement milk discharged from the tip of a multi-shaft mixing auger or the like (not shown), and is constructed by inserting a core material 40 into the soil cement before it hardens.

[0042] The soil cement column-type continuous wall 20 shown in the figure not only serves as a retaining wall when constructing the building 10, but also functions as the foundation of the building 10 after it is constructed by being joined to the underground section 11 of the building 10.

[0043] Of the core material 40 embedded in the soil cement 30, a second shear connector 50 consisting of a plurality of headed studs is welded to the first flange 42 on the upper building 10 side and protrudes laterally, and the protruding second shear connector 50 is embedded in the base plate 12 of the underground portion 11, thereby integrating the building 10 and the soil cement diaphragm-pillared wall 20. Here, the illustrated example is one in which the second shear connector 50 is joined to the base plate 12, but the second shear connector 50 may also be joined to the outer columns 13 and an exterior wall (not shown) joined to the outer columns 13 in addition to the base plate 12.

[0044] The ground G in the illustrated example has a non-bearing layer G1 with a relatively small N value, and a bearing layer G2 below the non-bearing layer G1 with a large N value. The non-bearing layer G1 is, for example, a sand layer or a clayey soil layer, and the bearing layer G2 is, for example, a gravel layer, a gravel layer, or clayey soil with an N value of 10 or more. If the non-bearing layer G1 is a clayey soil layer, the surface friction force between the soil cement 30 and the non-bearing layer G1 can be fully expected, and even if it is a sandy layer, the surface friction force can be expected to a certain extent.

[0045] The N value defining the non-support layer G1 can be set to, for example, about 5 or less, and the N value defining the support layer G2 can be set to, for example, about 30 or more, but the method for setting each N value is left to the designer.

[0046] The tip 45 of the core material 40 can be set on the top surface of the support layer G2 or at a position slightly embedded in the support layer G2. On the other hand, the bottom end 35 of the soil cement 30 in which the core material 40 is buried can be set at a position embedded, for example, about 1d (d is the diameter of the soil cement 30) or 1m into the support layer G2.

[0047] The building load N (vertical load) acting on the base 12 from the outer columns 13 etc. of the underground portion 11 is transmitted to the core material 40 of the soil cement column-type continuous wall 20 via the second shear connector 50, from the core material 40 to the surrounding soil cement 30, and from the soil cement 30 to the surrounding ground G, thereby ensuring the bearing capacity (vertical bearing capacity) of the soil cement column-type continuous wall 20.

[0048] This vertical bearing capacity is the sum of the tip bearing force Q1 that the lower end 35 of the soil cement 30 receives from the supporting layer G2 below, and the peripheral friction force Q2 that the peripheral surface of the soil cement 30 receives from the surrounding ground G.

[0049] On the other hand, the building load N is transmitted from the core material 40 to the surrounding soil cement 30 due to the adhesion resistance between the core material 40 and the soil cement 30 and the bearing resistance of the soil cement 30 at the tip 45 of the core material 40. In the illustrated example, a plurality of headed studs 60 (an example of a first shear connector) are provided that protrude laterally from the web 41 of the core material 40, and the headed studs 60 are embedded in the soil cement 30, thereby obtaining shear resistance and bearing resistance, and these additional forces improve the transmission of the building load N to the soil cement 30.

[0050] One way to increase the various resistance forces between the core material 40 and the soil cement 30, and between the soil cement 30 and the surrounding ground, is to increase the cement ratio in the soil cement. Specifically, the lower region of the soil cement 30 required for design is made of high-strength soil cement 31 with a high cement ratio and a rich mix, and the other upper region is made of low-strength soil cement 32 with a lean mix and a low cement ratio.

[0051] In the illustrated example, when the height from the lower end 12a of the base plate 12 to the lower end 35 of the soil cement 30 is t1, the range of the high-strength soil cement 31 is set to the height required for design within this height t1.

[0052] In other words, the range of the high-strength soil cement 31 is not limited to the area of ​​the supporting layer G2, but extends up to the middle of the non-supporting layer G1, so the application range of the high-strength soil cement 31 can be adjusted according to the required strength, preventing restrictions on the improvement of strength and allowing the formation of a soil cement column-type continuous wall 20 with a high degree of design freedom.

[0053] In addition, in the foundation structure of the building described in the aforementioned Patent Document 1, the high-strength soil cement is limited to the supporting layer, which limits the improvement in the bearing capacity of the soil cement column wall, resulting in a foundation structure with low design freedom.

[0054] Here, the low-strength soil cement 32 has a compressive strength of 0.5 N / mm 2 , which is the compressive strength of the soil cement forming the soil cement column-type continuous wall of a general earth retaining wall. 2 The soil cement is formed with a lean mix.

[0055] On the other hand, high-strength soil cement 31 has a compressive strength of 0.5N / mm 2 Exceeding 5N / mm 2 The soil cement formulation (rich formulation) is in the range of

[0056] In addition, in the design of high-strength soil cement 31, if the cement ratio is set high (for example, 5N / mm 2 Since a high-strength soil cement 31 with a cement ratio that can exert a compressive strength close to that of the original soil is shorter in height than when the cement ratio is set lower, the mix is ​​set from the perspectives of both cement ratio and height.

[0057] In Figure 1, the height level at which high-strength soil cement 30 is required by design, in other words, the design switching level between the high-strength soil cement 31 below and the low-strength soil cement 32 above, is L1 (depth from the underside of the base plate 12 is t2).

[0058] However, since it is difficult to carry out construction strictly at the switching level L1, as shown in Figure 1, the switching level L2, which is ΔL higher than the design switching level L1, is set as the construction switching level, and high-strength soil cement 31 is constructed below the construction switching level L2 (depth from the underside of the base plate 12 is t3) and low-strength soil cement 32 is constructed above it.

[0059] Here, ΔL can be set to 3d and a length of 2 m or more, where d is the diameter of the soil cement.

[0060] In this way, by setting the construction switching level L2 between high-strength soil cement 31 and low-strength soil cement 32 at a position 3d and 2m or more above the design switching level L1, it is possible to reliably prevent low-strength soil cement 32 from being mixed into areas where high-strength soil cement 31 is required due to construction errors, etc.

[0061] As described above, a plurality of headed studs 60 are provided below the web 41 of the core material 40. More specifically, a plurality of headed studs 60 are joined by welding or the like at intervals along the longitudinal direction of the web 41 in the range of the high-strength soil cement 31 (in the range deeper than the design switching level L1), and as shown in Figure 2, the headed studs 60 are joined to both sides of the web 41.

[0062] Since the shear resistance and bearing resistance of the headed studs 60 embedded in the soil cement 30 depend on the strength of the soil cement 30, by embedding the headed studs 60 inside the high-strength soil cement 31, which has a rich composition, it is possible to achieve good transmission of the building load N to the soil cement 30 with as few headed studs 60 as possible.

[0063] The building 100A shown in Figure 3 differs from the building 100 in which headed studs 60 are connected in that a plurality of burring shear connectors 70 (another example of the first shear connector) are connected at intervals along the longitudinal direction to the web 41 of the core material 40 that forms the soil cement column-type continuous wall 20, which is in the range of the high-strength soil cement 31 (in the range deeper than the design switching level L1).

[0064] As shown in Figures 4 and 5, the barring shear connector 70 comprises a perforated steel plate 71 and a frame-shaped protrusion 78 provided around a hole 75 on a wide surface 72 of the perforated steel plate 71, and an end surface 73 (end portion) of the perforated steel plate 71 is welded to the web 41.

[0065] The perforated steel plate 71 in the illustrated example is rectangular (square or rectangular) when viewed from the front, and has circular holes 75 (through holes) when viewed from the front provided in its wide surface 73. The linear shape of the frame-shaped protrusion 78 is circular and follows the linear shape of the holes 75, and therefore the frame-shaped protrusion 78 is cylindrical.

[0066] Here, the first shear connector 70 in the illustrated example is a burring shear connector in which burring processing has been applied to a steel plate, but it may also be a shear connector in which a frame-shaped protrusion 78 is welded to the wide surface 72 of a perforated steel plate 71.

[0067] As shown in FIG. 4, in the soil cement diaphragm wall 20, high-strength soil cement 31 is filled into the holes 75 of the perforated steel plate 71 of the first shear connector 70 and the inside of the frame-shaped protrusion 78.

[0068] 4, two first shear connectors 70 at the same level are welded to two wide surfaces 41a of the web 41 of the core material 40 at positions spaced apart from each other. If the thickness of the web 41 is relatively thin, welding the first shear connectors 70 to corresponding positions on the two wide surfaces 41a is likely to cause welding stress in the web 41, so the first shear connectors 70 are welded to positions spaced apart from each other as in the illustrated example.

[0069] If the thickness of the web 41 is relatively large and welding stress is unlikely to occur in the web 41 even if the first shear connectors 70 are welded to corresponding positions on the two wide surfaces 41a, two first shear connectors 70 at the same level may be welded to corresponding positions in the center of the web 41, for example.

[0070] As shown in Figure 5, when the first shear connector 70 (the core material 40 to which it is welded) is erected in the X1 direction inside the high-strength soil cement 31, the frame-shaped protrusion 78 extending from the web 41 of the core material 40 is cylindrical, which makes it easier for the high-strength soil cement 31 to flow laterally in the X2 direction along its curved side, improving the erection properties of the core material 40.

[0071] For this reason, the lower linear portion of the perforated steel plate may also be processed into a quarter circle or semicircle, for example, to make it easier for the high-strength soil cement 31 to flow laterally (not shown).

[0072] As shown in Fig. 4, high-strength soil cement 31 is filled into the holes 75 of the perforated steel plate 71 and inside the frame-shaped protrusions 78, so that when a building load N (indentation load) or a pull-out load N2 acts on the core material (not shown), a shear resistance force S is exerted, as shown in Fig. 5. Furthermore, because the first shear connector 70 is equipped with the frame-shaped protrusions 78, a bearing resistance force P is exerted by the frame-shaped protrusions 78.

[0073] In addition, Figure 5 shows a state in which an upward bearing pressure resistance force P is exerted on the lower side of the frame-shaped protrusion 78 in response to a push-in load N1, but a downward bearing pressure resistance force is exerted on the upper side of the frame-shaped protrusion 78 in response to a pull-out load N2.

[0074] In this way, by welding the first shear connector 70 to the area corresponding to the high-strength soil cement 31 in the core material 40, a building 100A is formed that has high resistance to both the push-in load N1 and the pull-out load N2 acting from the building.

[0075] Although not shown, a first shear connector may be applied in which two frame-shaped protrusions 78 are provided around each of the holes 75 on the two wide surfaces 72 of the perforated steel plate 71. This first shear connector can further increase the bearing resistance.

[0076] Furthermore, although not shown in the drawings, a first shear connector may be applied that has an elliptical hole that is elongated in the vertical direction when viewed from the front, or a polygonal hole that is polygonal when viewed from the front, and that has a frame-shaped protrusion that follows the linear shape of the elliptical or polygonal hole.

[0077] Next, an example of a construction method for a building according to the embodiment will be described.

[0078] In a construction method for a building, first, prior to construction of the building, a soil cement diaphragm wall having, for example, a rectangular frame shape in plan view is constructed around the construction area of ​​the building as an earth retaining wall. More specifically, as shown in Fig. 7, a plurality of outer columns 13 are joined to the base slab 12 of the building at intervals in the circumferential direction in plan view, and the soil cement diaphragm wall 20 comprises a load-bearing wall 20A that supports the building load N transmitted from the base slab 12 and a non-load-bearing wall 20B that does not support the building load N.

[0079] The building load N acting from the outer columns 13 to the base slab 12 is assumed to be transmitted downward while being dispersed and spread at an angle of 45° inside the base slab 12 toward its underside.Therefore, the soil cement column-type continuous wall 20 within the range taking into account the spread of the building load N on the base slab 12 is assumed to form a load-bearing wall 20A, and the rest are assumed to be non-load-bearing walls 20B.

[0080] The soil cement 30 forming the load-bearing wall 20A is formed by applying low-strength soil cement 32 and high-strength soil cement 31.

[0081] The method of construction of the soil cement 30 can be the well-known SMW (Soil Mixing Wall) method, etc., which begins with the removal of underground obstacles, the installation of a guide wall (not shown), the mixing of the soil cement, and the drilling and mixing of the designed cement slurry from the tip of the auger head of a multi-shaft auger machine or the like.

[0082] In the construction of the soil cement 30 that forms the load-bearing wall 20A of the soil cement column-type continuous wall 20, as shown in Figure 6, drilling and mixing are carried out using lean soil cement up to the construction switching level L2, at which point the mix is ​​switched to rich mix, and drilling and mixing is carried out using rich soil cement up to the designed soil cement construction depth.

[0083] At the designed soil cement application depth, the auger head is turned and raised to the application switching level L2, then turned again and pushed down to the designed soil cement application depth, and bottom hole mixing is performed.

[0084] Next, the auger head is turned again to raise it to the construction switching level L2, and at the construction switching level L2 the mix is ​​switched to a lean mix, and the lean mix soil cement is used to raise the auger head.

[0085] Through the above-described series of construction cycles, the soil cement 30 that forms the load-bearing wall 20A is constructed.

[0086] Furthermore, when constructing the high-strength soil cement 31, it is preferable to add a retarder to the rich-mix soil cement before construction, as this delays the hardening of the high-strength soil cement, which is accelerated due to its rich mix, and ensures good workability when erecting the core material 40 into the high-strength soil cement 31.

[0087] The load-bearing wall 20A has high-strength soil cement 31 and low-strength soil cement 32. In contrast, the non-load-bearing wall 20B does not support the building load N, and is therefore composed only of low-strength soil cement 32. In this way, by forming the soil cement of the load-bearing wall 20A with two types of rich mix and lean mix, and forming the soil cement of the non-load-bearing wall 20B with a lean mix, it is possible to form a soil-cement diaphragm columned wall 20 with load-bearing walls 20A and non-load-bearing walls 20B having high-strength soil cement 31 in necessary areas, with excellent economic efficiency.

[0088] Returning to Figure 7, in the construction of a soil cement diaphragm wall, which functions only as a retaining wall and therefore does not have a load-bearing wall, as in the construction of a conventional soil cement diaphragm wall, the wall is constructed starting from the left or right side (in the comparative example in Figure 7, construction starts from the left).

[0089] On the other hand, in this example (the embodiment in Figure 7) in which the soil cement pilaster-type continuous wall 20 has load-bearing walls 20A and non-load-bearing walls 20B alternatingly, the non-load-bearing walls 20B having only low-strength soil cement are constructed first, and then the load-bearing walls 20A are constructed between the non-load-bearing walls 20B that have already been constructed.

[0090] This construction method can prevent the high-strength soil cement 31 from entering the area where the non-load-bearing wall 20B is to be formed, and the load-bearing wall 20A and the non-load-bearing wall 20B can be constructed in the areas where they should be formed.

[0091] Here, as shown in FIG. 7, the core material 40 in the non-load-bearing wall 20B does not need to support the building load N like the core material 40 in the load-bearing wall 20A, so its length is set to be relatively short.

[0092] As described above, the soil cement prismatic continuous wall 20 having the load-bearing wall 20A and the non-load-bearing wall 20B is constructed around the building (step A).

[0093] Next, a portion of the soil cement 30 at the upper end of the soil cement diaphragm wall 20 is cut away to expose a portion of the core material 40, and a second shear connector 50 is joined to the exposed portion (step B).

[0094] Next, the base plate 12 is constructed so as to bury the second shear connectors 50, and the base plate 12 and the soil cement diaphragm wall 20 are joined together, thereby constructing the building 100 (step C).

[0095] According to this construction method, when constructing the load-bearing wall 20A that supports the building load N, relatively low-strength low-strength soil cement 32 is constructed at the top, and relatively high-strength high-strength soil cement 31 is constructed at the bottom, and the high-strength soil cement 31 is constructed in the range from the middle of the non-bearing layer G1 to the bearing layer G2.As a result, the construction position of the high-strength soil cement 31 is not limited to the bearing layer G2 but extends to the middle of the non-bearing layer G1, and therefore the bearing strength of the soil cement column wall 20 (load-bearing wall 20A) can be changed by adjusting the construction range of the high-strength soil cement 31, which makes it possible to prevent restrictions on the improvement of bearing strength and increase the degree of design freedom.

[0096] The present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0097] 10: Building 11: Underground 12: Bottom board 12a: Bottom edge 13: Outer pillar (pillar) 14: Ceiling slab 15: Middle pillar 20: Soil cement diaphragm wall 20A: Load-bearing wall (soil cement diaphragm wall) 20B: Non-load bearing wall (soil cement diaphragm wall) 30: Soil cement 31: High-strength soil cement 32: Low-strength soil cement 35: Bottom edge 40: Core material (H-beam) 41:Web 41a: Wide surface 42: First flange 43: Second flange 45: Tip 50: Headed stud (second shear connector) 60: Headed stud (first shear connector) 70: Barring shear connector (first shear connector) 71: Perforated steel plate 72: Wide surface 73: End face (end) 75: Hole 78:Frame-like projection 100, 100A: Buildings G: Ground G1: Non-supporting layer G2: Support layer Ga: Drilling N: Building load (vertical load) N1: Indentation load N2: Pull-out load S: Shear resistance P: Bearing resistance force Q1:Tip bearing capacity Q2: Circumferential friction force L1: Design switching level L2: Construction switching level

Claims

1. A building in which at least a basement of an underground portion of a building located in the ground is joined to a soil cement continuous column wall provided around the building, and the soil cement continuous column wall has a steel core material buried inside the soil cement, The soil cement penetrates the non-bearing layer of the ground and is embedded in the middle of the bearing layer below it, The soil cement comprises a high-strength soil cement located at the bottom and having a relatively high strength, and a low-strength soil cement located at the top and having a relatively low strength, A building characterized in that the high-strength soil cement is provided in the range from the middle of the non-supporting layer to the supporting layer.

2. The building according to claim 1, wherein a first shear connector is provided in a region of the core material corresponding to the high-strength soil cement.

3. 3. The building of claim 2, wherein the first shear connector is a headed stud.

4. 3. The building according to claim 2, wherein the first shear connector comprises a perforated steel plate and a frame-shaped protrusion provided around the hole on the wide surface of the perforated steel plate.

5. A plurality of columns are joined to the base of the building at intervals in the circumferential direction in a plan view, and the building load is transmitted to the base via the plurality of columns, The soil cement diaphragm wall comprises a load-bearing wall that supports the building load transmitted from the base plate and a non-load-bearing wall that does not support the building load, 2. The building described in claim 1, characterized in that at least the soil cement forming the load-bearing wall is embedded in the middle of the supporting layer, and the soil cement comprises the high-strength soil cement and the low-strength soil cement.

6. A construction method for a building in which at least a basement of an underground portion of a building located in the ground is joined to a soil cement diaphragm wall provided around the building, Step A: constructing a soil cement column-type continuous wall by placing soil cement in the ground and erecting a steel core material inside the soil cement; Step B: cutting the soil cement at the upper end of the soil cement diaphragm wall to expose a portion of the core material and joining a second shear connector to the exposed portion; and step C of joining the base plate and the soil cement columnar continuous wall by embedding the second shear connector in the base plate, In the step A, A method of constructing a building, characterized in that the soil cement penetrates the non-bearing layer of the ground and embeds itself halfway into the bearing layer below, and at this time, relatively low-strength low-strength soil cement is laid above, and relatively high-strength high-strength soil cement is laid below, and the high-strength soil cement is laid in the range from the middle of the non-bearing layer to the bearing layer.

7. In the step A, When the diameter of the soil cement is d, 7. A construction method for a building as described in claim 6, characterized in that the construction switching level between the high-strength soil cement and the low-strength soil cement is set at a position 3d and 2 m or more above the design switching level.

8. In the step A, 7. The method for constructing a building according to claim 6, characterized in that a retarder is added to the high-strength soil cement before construction.

9. A plurality of columns are joined to the base of the building at intervals in the circumferential direction in a plan view, The soil cement diaphragm wall comprises a load-bearing wall that supports the building load transmitted from the base plate and a non-load-bearing wall that does not support the building load, In the step A, The soil cement forming the load-bearing wall is formed by applying the low-strength soil cement and the high-strength soil cement, 7. The method for constructing a building according to claim 6, wherein the soil cement forming the non-load-bearing wall is formed by applying the low-strength soil cement.

10. The soil cement diaphragm wall comprises alternating load-bearing walls and non-load-bearing walls around the periphery of the building; In the step A, 10. The method for constructing a building according to claim 9, wherein the non-load-bearing walls are constructed first, and the load-bearing walls are constructed between the non-load-bearing walls that have already been constructed.

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