JP6994919B2 - Ground improvement solid foundation method - Google Patents

Description

The present invention relates to a ground improvement solid foundation method for small-scale buildings such as detached wooden houses, and is particularly suitable as a countermeasure against ground freezing in cold regions.

In cold regions such as Hokkaido where the ground freezes, the water freezes and the volume increases, which may adversely affect the foundation. In other words, the main factors that affect the frost heaving of the ground are temperature, soil quality, and water, and they occur when these three conditions are met at the same time, but it is said that the influence of water is the largest. Therefore, when constructing a solid foundation to build a building, the actual situation is that the local government in which it is located sets its own freezing depth.

However, in the current solid foundation, it is a fact that such effective measures were not taken against this freezing depth, and the depth of the ground improvement part is usually only about 250 mm from the GL line. There wasn't. Therefore, it becomes difficult to completely block the water outside the ground improvement part from entering the foundation through the ground improvement part, and it is inevitable that the ground will rise due to the increase in volume due to the freezing of this water. As a result, there is a problem that the foundation may be adversely affected, such as the foundation being lifted and deformed.

According to the applicant's search, there is Patent Document 1 as a method of constructing a building and a heat insulating material in which a heat insulating function is added to a foundation portion as prior art documents.

However, in this building and construction method, only a heat insulating material is provided on the outer circumference from the upper end to the lower end of the reinforced concrete cloth foundation, running costs are suppressed, and the underfloor space is almost the same as the internal space of the building body. It can be expected to have the effect of creating a temperature environment and designing the depth of the foundation of the building to be shallower than the freezing depth in the frozen area of the ground, but the height of the lower end of the foundation is constructed to be almost the same as the freezing depth. Therefore, it was not possible to prevent water outside the buried portion of the foundation from entering the foundation from the lower side of the buried portion.

Japanese Unexamined Patent Publication No. 9-60140

Therefore, the present invention can solve the problem of the conventional technique and block the water outside the ground improvement part (the buried part of the foundation) from entering the foundation through the ground improvement part, and it is possible to prevent the water from entering the foundation in a cold region. It is an object of the present invention to provide a ground improvement solid foundation method suitable for ground freezing countermeasures in Japan.

In order to solve the above problems, the invention according to claim 1 constructs a rising portion along the lower end of a pillar or a bearing wall of a building, and a bottom plate portion made of a reinforced concrete slab covering the entire building surface of the building. In the ground improvement solid foundation method to be carried out, a step of excavating a trench groove for creating a ground improvement part having a predetermined width in the ground below the bottom plate part and deeper than the freezing depth from the ground surface, and a step required for the bottom surface of the trench groove. A step of laying a number of crushed stones to form a crushed stone portion having a predetermined thickness, a step of forming a ground improvement portion for a solid foundation with ground improvement in a trench groove above the crushed stone portion, and a step of forming the ground improvement portion of the ground improvement portion. It is characterized by having a process of arranging a solid foundation reinforcement on the upper part, placing concrete, and constructing a rising portion .

The invention according to claim 2 is a ground improvement solid foundation method for constructing a rising portion along the lower end of a pillar or a bearing wall of a building and a bottom plate portion made of a reinforced concrete slab over the entire building surface of the building. A step of excavating a trench groove for creating a ground improvement portion having a predetermined width in the ground below the bottom plate portion and deeper than the freezing depth from the ground surface, and a plate-shaped foamed resin on the outward inner wall surface of the trench groove. The process of providing the material, the process of forming the ground improvement part for the solid foundation with the ground improvement in the trench groove inside the foamed resin material, and the step of arranging the solid foundation reinforcement above the ground improvement part and concrete. It is characterized by having a process of placing and constructing a rising portion .

The invention according to claim 3 is a ground improvement solid foundation method for constructing a rising portion along the lower end of a pillar or a bearing wall of a building and a bottom plate portion made of a reinforced concrete slab over the entire building surface of the building. A step of excavating a trench groove for creating a ground improvement portion having a predetermined width in the ground below the bottom plate portion and deeper than the freezing depth from the ground surface, and a plate-shaped foamed resin on the outward inner wall surface of the trench groove. A step of providing the material, a step of laying a required number of crushed stones on the bottom surface of the trench groove inside the foamed resin material, and a step of providing a crushed stone portion having a predetermined thickness so as to form an L shape with the foamed resin material. The process of forming a solid foundation ground improvement part with ground improvement in the trench groove partitioned by the crushed stone part and the foamed resin material, and placing concrete by arranging the solid foundation reinforcement above the ground improvement part. It is characterized by having a process of constructing a rising portion .

The invention according to claim 4. In the ground improvement solid foundation method to construct a rising part along the lower end of a building pillar or a bearing wall and a bottom plate part made of reinforced concrete slabs over the entire building surface, the ground below the bottom plate part. A step of excavating a trench groove for creating a ground improvement part having a predetermined width and deeper than the freezing depth from the ground surface, a step of providing a plate-shaped foamed resin material on the bottom surface of the trench groove, and an outward direction of the trench groove. A step of providing a plate-shaped second foamed resin material on the inner wall surface so as to form an L-shape with the foamed resin material, and ground improvement in the trench groove partitioned by the foamed resin material and the second foamed resin material. It is characterized by having a step of forming a ground improvement portion for a solid foundation that has been applied, and a step of arranging a solid foundation reinforcement arrangement on the upper part of the ground improvement portion and placing concrete to construct a rising portion .

The invention according to claim 5 is characterized in that, in claim 4 , the foamed resin material and the second foamed resin material are polystyrene foam.

The present invention is as described above, and according to the invention of claim 1, in the ground improvement solid foundation method, the ground has a predetermined width on the ground below the bottom plate portion and is deeper than the freezing depth from the ground surface. The process of excavating a trench groove for creating an improved part, the process of laying a required number of crushed stones on the bottom surface of the trench groove to form a crushed stone part of a predetermined thickness, and the ground improvement in the trench groove above the crushed stone part. Since it has a step of forming a ground improvement part for a solid foundation and a step of placing a solid foundation reinforcement on the upper part of the ground improvement part and placing concrete to construct a rising part , these steps are used. In the ground improvement solid foundation to be constructed, the water outside the ground improvement part can be blocked from entering the foundation through the ground improvement part by the solid foundation ground improvement part. Therefore, since the foundation is not lifted and deformed and has no adverse effect on the foundation, it can be expected to have an excellent effect of being suitable as a countermeasure against ground freezing in cold regions.

According to the invention according to claim 2, in the ground improvement solid foundation method, a step of excavating a trench groove for creating a ground improvement portion having a predetermined width and deeper than the freezing depth from the ground surface in the ground below the bottom plate portion. And a step of providing a plate-shaped foamed resin material on the outward inner wall surface of the trench groove, and a step of forming a solid foundation ground improvement portion in which the trench groove inside the foamed resin material is ground-improved. Since it has a process of arranging a solid foundation reinforcement in the upper part of the ground improvement part, placing concrete, and constructing a rising part, even in the ground improvement solid foundation constructed by these steps, the ground improvement The water on the outside of the portion can be blocked from entering the foundation through the ground improvement portion by the solid foundation ground improvement portion and the foamed resin material on the outside thereof, and has the same effect as the invention according to claim 1. Can be expected.

According to the invention of claim 3, in the ground improvement solid foundation method, a step of excavating a trench groove for creating a ground improvement portion having a predetermined width and deeper than the freezing depth from the ground surface in the ground below the bottom plate portion. A step of providing a plate-shaped foamed resin material on the outward inner wall surface of the trench groove, and a crushed stone portion having a predetermined thickness by laying a required number of crushed stones on the bottom surface of the trench groove inside the foamed resin material. A step of forming an L-shape with the foamed resin material, a step of forming a solid foundation ground improvement portion in which the trench groove partitioned by the crushed stone portion and the foamed resin material is formed, and the ground . Since there is a process of arranging a solid foundation reinforcement in the upper part of the improved part, placing concrete, and constructing a rising part, even in the ground improvement solid foundation constructed by these processes, the outside of the ground improvement part. The invention according to claim 1, wherein the water can be blocked from entering the foundation through the ground improvement part by the solid foundation ground improvement part, the foamed resin material on the outside thereof, and the crushed stone part on the lower side. The same effect can be expected.

According to the invention of claim 4, in the ground improvement solid foundation method, a step of excavating a trench groove for creating a ground improvement portion having a predetermined width and deeper than the freezing depth from the ground surface in the ground below the bottom plate portion. And the step of providing a plate-shaped foamed resin material on the bottom surface of the trench groove, and the plate-shaped second foamed resin material on the outward inner wall surface of the trench groove so as to be L-shaped with the foamed resin material. A step of forming a ground improvement part for a solid foundation in which a ground improvement is applied to a trench groove partitioned by the foamed resin material and a second foamed resin material, and a solid foundation arrangement on the upper part of the ground improvement part. Since it has a process of arranging streaks, placing concrete, and constructing a rising part, even in the ground improvement solid foundation constructed by these processes, the water outside the ground improvement part passes through the ground improvement part. It is possible to block the entry into the foundation by the solid foundation ground improvement portion, the second foamed resin material on the outside thereof, and the foamed resin material on the lower side, and the same effect as that of the invention according to claim 1. Can be expected.

FIG. 1 is a plan sectional view of a ground-improved solid foundation along the line AA of FIG. 2 showing the first embodiment of the present invention. It is a vertical sectional view of the same as above. It is a vertical sectional view corresponding to FIG. 2 of the ground improvement solid foundation which shows Embodiment 2. FIG. It is a vertical sectional view corresponding to FIG. 2 of the ground improvement solid foundation which shows Embodiment 3. FIG. It is a vertical sectional view corresponding to FIG. 2 of the ground improvement solid foundation which shows Embodiment 4. FIG.

Embodiments of the present invention will be described with reference to the drawings.
<Embodiment 1>

First, the ground improvement solid foundation according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
Reference numeral 1 in the figure indicates a ground improvement solid foundation, and this solid foundation 1 is continuous with the rising portion 2 provided along the lower end of the pillar or bearing wall of the building and the bottom of the rising portion. The bottom plate portion 3 provided over the entire building surface, the ground improvement portions (stabilizers) 4 and 5 provided in the ground below the bottom plate portion, and the lower surface of the ground improvement portion 4 having a predetermined thickness. It is composed of the formed crushed stone portion 6.

The rising portion 2 is a reinforced concrete structure having a vertically long rectangular shape (see FIG. 2) with a predetermined bar arrangement according to the structural design, and imparts a predetermined flexural rigidity to the foundation to apply a load to the building. It has a function of transmitting to the bottom plate portion 3.

The bottom plate portion 3 is a structure made of a reinforced concrete slab in which predetermined reinforcement is arranged according to the structural design, and has a function of evenly transmitting the load of the building to the ground. When the ground on which the solid foundation 1 is constructed is liable to cause uneven subsidence due to liquefaction, a plurality of holes (not shown) for injecting a chemical solution are provided in the bottom plate portion 3 at a predetermined ratio, for example, so as to be uniform. It may be provided.

The ground improvement portions 4 and 5 have been referred to as stabilizers from the past, and are provided in a grid pattern in a plan view and have a function of enhancing the resistance force by supporting the bottom plate portion 3 of the ground. There is. In this example, the ground improvement portion 4 has a vertically long rectangular shape with a vertical cross section, and its dimensions are longer than the width (in this example, the height is about 50 cm and the width is about 45 cm). The upper surface thereof is in contact with the lower surface of the bottom plate portion 3, and the lower surface is in contact with the upper surface of the crushed stone portion 6. Further, the outer surface of the ground improvement portion 4 is flush with the outer surface of the rising portion 2. The lower surface of the ground improvement portion 4 having such a shape and dimensions is located below the freezing depth (in this example, the depth is set to 60 cm). In this example, the ground improvement portion 5 has a horizontally long rectangular shape with a vertical cross section, and its dimensions are shorter than the width (in this example, the height is about 30 cm and the width is about 45 cm). The depth deeper than the freezing depth means a depth equal to or greater than the freezing depth.

The crushed stone portion 6 is formed so that its upper surface is in contact with the lower surface of the ground improvement portion 4, and its dimensions are shorter than the width (in this example, the height is about 15 cm and the width is about 45 cm).

In order to construct the ground improvement solid foundation 1 as described above, the following construction method is used.

First, as shown in FIG. 1, the ground in or near the foundation construction part after the predetermined foundation has been rooted is excavated with a heavy excavation machine such as a small backhoe to a predetermined width from the ground surface. A trench ditch 7 for creating the ground improvement portion 4 deeper than the freezing depth is excavated. The trench groove 8 for creating the ground improvement section 5 is also excavated in parallel.

Next, a required number of crushed stones are laid on the bottom surface of the trench groove 7 for the ground improvement portion 4 to form a crushed stone portion 6 having a predetermined thickness. When forming the crushed stone portion 6, the upper surface thereof is set to be deeper than the freezing depth, that is, further below the lower line of the freezing depth. After that, a required amount of cement-based solidifying material such as soil cement is added to the excavated soil from above the crushed stone portion 6 and mixed and stirred to obtain improved soil (reinforced soil), which is then backfilled in the original state. Backfilling is performed several times while rolling with a rammer, thereby creating a strong and tough ground improvement section 4. Similarly, for the trench groove 8 for the ground improvement portion 5, the ground improvement portion 5 is formed by backfilling and rolling the improved soil. After constructing the ground improvement parts 4 and 5, solid foundation reinforcements are placed and concrete is placed in the ground area including the upper part of these ground improvement parts to construct the bottom plate part 3 and the ground improvement part 4 When the solid foundation reinforcement is arranged on the upper part and concrete is placed to construct the rising portion 2, the ground improvement solid foundation 1 integrated with the ground improvement portions 4 and 5 is created.

According to the ground-improved solid foundation 1 constructed as described above, the ground-improved solid foundation 4 is formed in the trench groove 7 for creating the ground-improved portion deeper than the freezing depth from the ground surface. Since it has a structure, water outside the ground improvement portion 4 does not enter the foundation through the ground improvement portion 4, and the problem as before can be solved.

<Embodiment 2>

FIG. 3 shows the ground improvement solid foundation 11 according to the second embodiment. In order to construct the ground improvement solid foundation 11 according to the second embodiment, after forming the same trench groove 17 as the trench groove of the first embodiment, the outward inner wall surface of the trench groove is used as a foamed resin material. A plate-shaped polystyrene foam 19 is provided, and a solid foundation ground improvement portion 14 in which the trench groove 17 inside the polystyrene foam 19 is further ground-improved is formed in the same manner as the ground improvement portion 4 of the first embodiment. The solid foundation ground improvement portion 15 having the ground improvement also applied to the trench groove 18 is formed in the same manner as the ground improvement portion 5 of the first embodiment. After that, the same as the first embodiment is performed, whereby the ground improvement solid foundation 11 integrated with the ground improvement portions 14 and 15 is created.

The polystyrene foam 19 is made of a plate material having a predetermined thickness, and its dimensions are such that the height is longer than the width (thickness) (in this example, the height is about 50 cm and the thickness is about 2 cm). Therefore, the ground improvement portion 14 is displaced inward of the foundation by the thickness thereof. The polystyrene foam 19 is provided on the outer surface of the ground improvement portion 14 so as to cover the outer periphery thereof, so as to prevent water from the outside of the ground improvement portion 14 from entering the solid foundation 1 from the lower side of the ground improvement portion 14. It has become. A plurality of polystyrene foams 19 are usually provided by connecting a plurality of polystyrene foams 19 along the trench groove 17.

Further, since the polystyrene foam 19 is made of extruded expanded polystyrene foam, it is difficult to transfer heat, does not absorb water, and is light and durable. Also, unlike a normal styrene board, it is not made by compacting the grains, so it does not easily become ragged and it is easy to cut straight lines.

Even in the solid foundation structure 11 as described above in which the polystyrene foam 19 is provided on the outside of the ground improvement portion 14 without providing the crushed stone portion on the lower side of the ground improvement portion 14, the water on the outside of the ground improvement portion 14 improves the ground. It does not enter the foundation through the portion 14, and the same action and effect as in the first embodiment can be expected.

<Embodiment 3>

FIG. 4 shows the ground improvement solid foundation 21 according to the third embodiment. In order to construct the ground improvement solid foundation 21 according to the third embodiment, after forming the trench groove 27 in the same manner as the trench groove 17 of the second embodiment, the foamed resin is formed on the outward inner wall surface of the trench groove. A plate-shaped polystyrene foam 29 is provided as a material. After that, a required number of crushed stones are laid on the bottom surface of the trench groove 27 inside the polystyrene foam 29, and the crushed stone portion 26 having a predetermined thickness is provided so as to form an L shape with the polystyrene foam 29. Further, a solid foundation ground improvement section 24 in which the trench groove 27 partitioned by the polystyrene foam 29 and the crushed stone section 26 is ground-improved is formed in the same manner as the ground improvement section 4 of the first embodiment. After that, the same applies to the first and second embodiments, whereby the ground improvement solid foundation 21 integrated with the ground improvement portions 24 and 25 is created. The ground improvement unit 24 has the same basic structure as the ground improvement unit 14 of the second embodiment, and also has the same height dimension.

In this case as well, the water outside the ground improvement portion 24 does not enter the foundation through the ground improvement portion 24, and the same effect can be expected.

<Embodiment 4>

FIG. 5 shows the ground improvement solid foundation solid foundation 31 according to the fourth embodiment. In order to construct the solid foundation 31 according to the fourth embodiment, after forming the trench groove 37 in the same manner as the trench groove 27 of the third embodiment, a plate-shaped foam resin material is formed on the bottom surface of the trench groove. Polystyrene foam 38 is provided. After that, a plate-shaped polystyrene foam 39 as a second foamed resin material is provided on the outward inner wall surface of the trench groove 37 so as to form an L-shape with the polystyrene foam 38. Further, a solid foundation ground improvement section 34 in which the trench groove 37 partitioned by both polystyrene foams 38 and 39 is ground-improved is formed in the same manner as the ground improvement section 4 of the first embodiment. After that, the same applies to the third embodiment, whereby the ground improvement solid foundation 31 integrated with the ground improvement portions 34 and 35 is created.

In the above, the polystyrene foam 38 is provided and then the polystyrene foam 39 is provided, but conversely, the polystyrene foam 39 may be provided first, and then the polystyrene foam 38 may be provided.

The polystyrene foam 38 has substantially the same dimensions as the polystyrene foam 39 (in this example, the polystyrene foam 38 has a width of 45 cm and a height of about 5 cm). Further, the height of the ground improvement portion 34 is the same as the height of the ground improvement portion 14 as in the ground improvement portion 24.

Further, since the polystyrene foam 38 is an extruded expanded polystyrene foam, like the polystyrene foam 19, it is difficult to transfer heat, does not absorb water, and is light and durable. Also, unlike a normal styrene board, it is not made by compacting the grains, so it does not easily become ragged and it is easy to cut straight lines.

In this case as well, the water outside the ground improvement portion 34 does not enter the foundation through the ground improvement portion 24, and the same effect can be expected.

As described above, the shapes and the like of the constituent members shown in the respective embodiments of the present invention are merely examples, and they may be other than those shown in the drawings as long as they have the same effect. Needless to say. Further, the polystyrene foam mentioned as the foamed resin material is merely an example.

1 Solid foundation 2 Rising part 3 Bottom plate part 4, 5 Ground improvement part 6 Crushed stone part 7, 8 Trench groove 11 Solid foundation 12 Rising part 13 Bottom plate part 14, 15 Ground improvement part 17, 18 Trench groove 19 Polystyrene foam (foam resin material) )
21 Solid foundation 22 Rising part 23 Bottom plate part 24,25 Ground improvement part 26 Crushed stone part 27 Trench groove 29 Polystyrene foam (foam resin material)
31 Solid foundation 32 Rising part 33 Bottom plate part 34,35 Ground improvement part 37 Trench groove 38,39 Polystyrene foam (foam resin material)

Claims (5)

In the ground improvement solid foundation method to construct the rising part along the lower end of the pillars and bearing walls of the building and the bottom plate part made of reinforced concrete slabs over the entire building surface of the building.
A step of excavating a trench groove for creating a ground improvement part having a predetermined width and a depth deeper than the freezing depth in the ground below the bottom plate portion, and a predetermined number of crushed stones being laid on the bottom surface of the trench groove. A step of forming a crushed stone portion of a thickness, a step of forming a ground improvement portion for a solid foundation with ground improvement in the trench groove above the crushed stone portion, and a solid foundation reinforcement arrangement above the ground improvement portion. A ground improvement solid foundation method characterized by having a process of placing concrete and constructing a rising part . In the ground improvement solid foundation method to construct the rising part along the lower end of the pillars and bearing walls of the building and the bottom plate part made of reinforced concrete slabs over the entire building surface of the building.
A step of excavating a trench groove for creating a ground improvement portion having a predetermined width in the ground below the bottom plate portion and deeper than the freezing depth from the ground surface, and a plate-shaped foamed resin on the outward inner wall surface of the trench groove. The process of providing the material, the process of forming the ground improvement part for the solid foundation with the ground improvement in the trench groove inside the foamed resin material, and the step of arranging the solid foundation reinforcement above the ground improvement part and concrete. A ground improvement solid foundation method characterized by having a process of placing and constructing a rising part . In the ground improvement solid foundation method to construct the rising part along the lower end of the pillars and bearing walls of the building and the bottom plate part made of reinforced concrete slabs over the entire building surface of the building.
A step of excavating a trench groove for creating a ground improvement portion having a predetermined width in the ground below the bottom plate portion and deeper than the freezing depth from the ground surface, and a plate-shaped foamed resin on the outward inner wall surface of the trench groove. A step of providing the material, a step of laying a required number of crushed stones on the bottom surface of the trench groove inside the foamed resin material, and a step of providing a crushed stone portion having a predetermined thickness so as to form an L shape with the foamed resin material. The process of forming a ground improvement part for a solid foundation with ground improvement in the trench groove partitioned by the crushed stone part and the foamed resin material, and placing the solid foundation reinforcement above the ground improvement part and placing concrete. A ground improvement solid foundation method characterized by having a process of constructing a rising part . In the ground improvement solid foundation method to construct the rising part along the lower end of the pillars and bearing walls of the building and the bottom plate part made of reinforced concrete slabs over the entire building surface of the building.
A step of excavating a trench groove for creating a ground improvement portion having a predetermined width in the ground below the bottom plate portion and deeper than the freezing depth from the ground surface, and a step of providing a plate-shaped foamed resin material on the bottom surface of the trench groove. A step of providing a plate-shaped second foamed resin material on the outward inner wall surface of the trench groove so as to form an L-shape with the foamed resin material, and the foamed resin material and the second foamed resin material. A process of forming a ground improvement part for a solid foundation with ground improvement in the partitioned trench groove, and a process of arranging a solid foundation reinforcement in the upper part of the ground improvement part and placing concrete to construct a rising part. A ground improvement solid foundation method characterized by having. The ground improvement solid foundation method according to claim 4 , wherein the foamed resin material and the second foamed resin material are polystyrene foam.

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