JP2007120240A - Foundation structure of building in weak ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foundation structure capable of correcting an inclination of a building while supporting weight in a well-balanced state even when unequal settlement is caused by restraining the occurrence of the unequal settlement in the building constructed above the weak ground. <P>SOLUTION: This foundation structure 10 of the building 11 in the weak ground can correct the inclination of the building 11 when the unequal settlement is caused in the building constructed above the weak ground, and is composed of a base layer 12 by a surface layer improving construction method arranged in a surface layer part of the foundation ground of the building 11, a plurality of support piles 13 by a columnar improving construction method arranged in the foundation ground by supporting a central part 12a of the base layer 12 and a mat foundation 14 arranged in layers above the base layer 12. The base layer 12 is formed higher by one state in the central part 12a supported by the support piles 13, and a central part 14a of the mat foundation 14 is placed, and adjusting sand 16 is filled in clearance 15 between the base layer 12 and the mat foundation 14 around the central parts 12a and 14a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a basic structure of a building in soft ground, which can correct the inclination of the building when uneven settlement occurs in a building constructed above the soft ground.

For example, if the ground that constitutes back marsh, coastal landfill, delta lowland, drowning valley, coastal sand bar, etc. is formed by peat or ground with slow consolidation, etc., it is soft ground There are many. Such soft ground has a small ground supporting force and is likely to continue to be consolidated and settled.Therefore, when building a building above the soft ground, a method of installing a supporting pile such as a steel pipe pile or a friction pile, Various methods are adopted as measures for soft ground such as a method for improving ground (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
JP-A-7-189249 JP 7-279184 A JP 2004-116156 A JP 2000-8398 A

  On the other hand, the soft ground is not uniform in ground properties due to changes in soil quality and layer thickness, etc., and if the consolidation settlement proceeds non-uniformly after the building is built, it tends to cause uneven settlement (unequal settlement) in the building. In addition, it is economically difficult to accurately understand the behavior of the soft ground after building the building by conducting a thorough ground survey, and pre-measures corresponding to the amount of subsidence are predicted in advance. That is practically difficult. Therefore, as a countermeasure against soft ground, not only does the structure of the foundation part of the building not have a structure that is unlikely to cause uneven settlement, but when the uneven settlement occurs, the technology that makes it possible to correct the slope due to the settlement afterwards. Development is desired.

  Moreover, although the technique which corrects the inclination of a building using a jack when the uneven subsidence arises in a building is disclosed (for example, refer to patent documents 4), only by jacking up the sinking part of a building Since it is necessary to correct the inclination while lifting the building while supporting the large weight of the building with the jack, the work becomes large and it is difficult to correct it while balancing the whole building. In addition, it takes a lot of work to re-integrate the frame of the lifted building with the foundation and foundation. If the integration is insufficient, stability may be lost and problems such as earthquake resistance may occur. .

  The present invention has been made paying attention to such a conventional problem, and can suppress the occurrence of uneven settlement in a building constructed above the soft ground, and even when uneven settlement occurs in the building, An object is to provide a foundation structure of a building on soft ground that can correct the inclination while supporting the weight of the building in a well-balanced manner and can easily secure the stability of the building even after the correction of the inclination. .

  The present invention is a foundation structure of a building that can correct the inclination of the building when a subsidence occurs in a building constructed above soft ground, and is provided on the surface layer portion of the foundation ground of the building Comprising a base layer, a plurality of support piles provided in the base ground to support a central portion of the base layer, and a solid foundation disposed on top of the base layer, The central part supported by the support pile is raised one step higher, the central part of the solid foundation is placed, and the clearance between the base layer and the solid foundation around the central part is adjusted. The above object is achieved by providing a foundation for a building in soft ground filled with sand.

  Further, according to the foundation structure of the building in the soft ground of the present invention, the base layer is a planar solid body formed by a surface layer improvement method, and the support pile is a columnar solid body formed by a column shape improvement method. It is preferable that it is a ligature.

  Furthermore, according to the foundation structure of the building in the soft ground according to the present invention, when the subsidence occurs in the building, the adjustment sand between the foundation layer and the solid foundation in the portion that becomes higher with the central portion as a fulcrum In addition, the inclination of the building can be easily adjusted by adding adjustment sand between the foundation layer and the solid foundation in the lowered portion.

  According to the basic structure of the building in the soft ground of the present invention, it is possible to suppress the occurrence of uneven subsidence in the building constructed above the soft ground, and to balance the weight of the building even if the subsidence occurs in the building. The inclination can be corrected while being supported, and the stability of the building can be easily secured even after the inclination is corrected.

  The basic structure 10 of the building in the soft ground according to a preferred embodiment of the present invention shown in FIGS. 1 to 3 is, for example, a residential building as a building on a landfill created by embankment above the soft ground. When building 11, it suppresses the occurrence of uneven settlement in the residential building 11 after construction, and for example, the residential building 11 sinks unevenly after several months to several decades, and the residential building 11 has a considerable degree. In order to be able to quickly correct such an inclination even when it is inclined, it is incorporated in advance when the residential building 11 is constructed.

  Here, even if consolidation settlement occurs in the soft ground, if the foundation ground of the residential building 11 sinks uniformly, no uneven settlement will occur, and there will be little effect on the life inside the residential building 11. Conceivable. On the other hand, when the foundation ground of the residential building 11 sinks unevenly and the residential building 11 sinks unevenly, for example, when the residential building 11 tilts beyond the allowable range of about 6/1000, For example, the base part 11a of the residential building 11 is cracked, it becomes difficult to open and close doors and windows, or an obstacle that causes an abnormal feeling of life occurs. The foundation structure 10 according to the present embodiment can easily adjust the inclination of the residential building 11 even when uneven settlement occurs in the residential building 11, and can stably support the frame portion after correcting the inclination. It has a configuration that can quickly restore the foundation structure.

  In FIGS. 1 to 3, as a main part of the foundation structure 10 of the present embodiment, the housing part 11 is omitted and only the foundation part 11 a is shown, and the foundation structure 10 of the present embodiment is shown. The landfilled ground created above the soft ground on which is installed is omitted. Furthermore, in this embodiment, the foundation part 11a of the residential building 11 is shown in a simplified manner so as to have a substantially rectangular planar shape.

  And the foundation structure 10 of the building in the soft ground of this embodiment is the foundation which made it possible to correct the inclination of the residential building 11 when uneven settlement occurs in the residential building 11 built above the soft ground. A base layer 12 provided on the surface layer portion of the foundation ground of the residential building 11, a plurality of support piles 13 provided in the foundation ground to support the central portion of the base layer 12, and the base layer 12 The base layer 12 has a central portion 12a supported by the support pile 13 that is raised one step higher, and the central portion 14a of the solid base 14 is placed thereon. The gap 15 between the base layer 12 and the solid base 14 around the central portions 12a and 14a is filled with adjustment sand 16.

  The base layer 12 constituting the base structure 10 of the present embodiment is preferably provided as a planar solid body formed by a surface layer improvement method (shallow layer processing method). The surface layer improvement method is a method in which a cement-type solidifying material such as lime or cement is mixed with the earth and sand of the surface layer portion of the improved ground, for example, by repeating agitation and thickness reduction every layer thickness of about 30 to 50 cm. This is a known method for forming a ground improvement layer. In this embodiment, the base layer 12 has a rectangular solid shape that is slightly larger than the base portion 11a of the residential building 11 and has a thickness of about 0.78 m, for example, by the surface layer improvement method. Formed as. In the present embodiment, the central portion 12a of the rectangular base layer 12 formed by the planar consolidated body is one step higher than the surrounding portion, for example, at a height of about 100 mm, as shown in FIG. It is a stepped part. A central portion 14a of the solid foundation 14 is placed on the central portion 12a, and a gap 15 of about 100 mm is held between the base layer 12 and the solid foundation 14 around the central portions 12a and 14a. (See FIG. 3).

  The basement layer 14 has a function of effectively suppressing subsidence and non-uniform subsidence of the residential building 11 by distributing the weight of the residential building 11 evenly to the foundation ground while dispersing the weight of the residential building 11 by a large ground contact area with respect to the foundation ground. As will be described later, when jacking up the solid foundation 14 in order to correct the inclination of the residential building 11, it also functions as a reaction force board that receives the reaction force of the jack. The base layer 14 can also exert a surface restraining effect that suppresses liquefaction of the ground during an earthquake. In addition, the base layer 14 does not necessarily need to be a planar solid body by the surface layer improvement construction method, and can be formed by using, for example, concrete or laying an iron plate.

  In the present embodiment, the support pile 13 provided in the foundation ground by supporting the central portion 12a, which is one step higher from the base layer 12, from the lower side is preferably a columnar shape formed by a columnar improvement method (deep shallow layer mixed processing method). It is formed as a consolidated body. In the columnar improvement method, a stirring rod with stirring blades is inserted into the ground at a predetermined depth, and the stirring rod is rotated while spraying a cement-based solidifying material such as cement, for example. It is a known method of forming inside. In the present embodiment, the support piles 13 are built in the ground below the central portion 12a of the base layer 12 by a columnar improvement method, for example, with a pile diameter and length of φ600, L = 5.0 m. .

  By providing the support pile 13 in the ground below the central portion 12a of the base layer 12, it is possible to strengthen the central portion of the residential building 11 to which a lot of building power is distributed when building on soft ground. At the same time, when the inclination of the residential building 11 is corrected as will be described later, the central portion 12a of the base layer 12 is firmly supported from below and can function more effectively as a fulcrum of leverage. . In addition, the pile diameter of the support pile 13, length, arrangement | positioning density, etc. are suitably designed according to the magnitude | size of the housing building 11, the property of a foundation ground, etc. Moreover, the support pile 13 does not necessarily need to be a columnar solid body formed by the columnar improvement method, and may be, for example, a sand pile, an RC pile, a PC pile, or the like. The construction of the support pile 13 is performed prior to the construction of the base layer 12.

  In this embodiment, the solid foundation 14 placed over the base layer 12 is made of concrete or reinforced concrete. For example, the base layer 12 is formed by the surface layer improvement method, and the adjustment sand 16 is laid around the central portion 12a. After finishing the upper surface to be flush with each other, the central portion 14a is placed in close contact with the central portion 12a of the base layer 12 by placing the formwork and, if necessary, placing reinforcing bars and placing concrete. Thus, it can be easily formed. As a result, the periphery of the central portions 12a, 14a of the base layer 12 and the solid foundation 14 that are in close contact with each other is 100 mm between the upper surface of the base layer 12 and the lower surface of the solid foundation 14 in a state where the adjustment sand 16 is filled. The gap 15 having a certain thickness is held. In addition, on the upper surface side of the solid foundation 14, a rising wall 17 is provided upright according to the floor plan shape of the housing portion of the residential building 11. Further, for example, a base is installed on the upper surface of the rising wall 17, and a housing part is assembled further upward to construct the residential building 11.

  The adjustment sand 16 filled in the gap 15 between the base layer 12 around the central portions 12a and 14a and the solid base 14 is made of, for example, mountain sand, river sand, sea sand, etc., and is buried with the base layer 12 interposed. By being separated from the creation ground, it is filled in a dry state. As a result, even if liquefaction of the ground occurs during an earthquake, this area is not affected. Moreover, when correcting the inclination of the residential building 11 as described later, water or air is used to adjust the adjustment sand 16 from the gap 15 between the base layer 12 and the solid base 14 as necessary. It can be easily put in and out. In addition, when the adjustment sand 16 is taken in and out using water, it is restored to a dry state so as not to be liquefied by sucking water with vacuum or applying heat to dry it.

  And according to the foundation structure 10 of the soft ground of this embodiment provided with the above-mentioned structure, it is possible to suppress the occurrence of uneven settlement in the residential building 11 constructed above the soft ground, and the residential building 11 Even if uneven settlement occurs, the inclination can be corrected while supporting the weight of the residential building 11 in a well-balanced manner, and the stability of the residential building 11 can be easily secured even after the inclination is corrected. .

  That is, according to this embodiment, the base layer 12 provided on the surface layer portion of the foundation ground of the residential building 11 transmits the weight of the residential building 11 evenly over a wide range to the foundation ground while being distributed. In addition, since the support pile 13 provided below the central portion 12a of the base layer 12 firmly supports the central portion to which a large amount of building force is distributed, the residential building 11 may be subsidized or unevenly subsidized. It is possible to effectively suppress the occurrence.

  Moreover, when uneven settlement occurs in the residential building 11, for example, a jack is set at a necessary place through a gap 15 between the base layer 12 and the solid foundation 14, and the base layer 12 and the solid foundation 14 are While supporting the majority of the load from the house building 11 at the closely contacted central portions 12a and 14a, the tilt can be easily corrected in a gradual manner using the central portions 12a and 14a as leverage points while expanding and contracting the jack. It becomes possible. In addition, it is possible to adjust the inclination of the building by removing the adjustment sand 16 in the gap 15 at the heightened portion with the central portions 12a and 14a as fulcrums and adding the adjustment sand 16 to the gap 15 at the lowered portion. Become. As a result, it is possible to correct the inclination while supporting the weight of the residential building 11 in a well-balanced manner, and the adjustment sand 16 is put into and out of the gap 15 between the base layer 12 and the solid foundation 14 even after the correction of the inclination. Thus, by maintaining the state in which the adjustment sand 16 is filled, the stability of the residential building 11 can be easily ensured.

  Furthermore, the basic structure 10 of the building according to the present embodiment can be economically constructed by employing inexpensive known methods such as a surface layer improvement method and a columnar improvement method.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the foundation portion and the base layer of the building do not necessarily have a substantially rectangular planar shape, and can be a base portion and a base layer of various shapes according to the floor plan of the building. Moreover, the building to be constructed does not necessarily need to be a residential building.

It is a schematic perspective view which shows the principal part of the foundation structure which concerns on preferable one Embodiment of this embodiment. It is a schematic plan view which shows the principal part of the foundation structure which concerns on preferable one Embodiment of this embodiment. It is a schematic side view which shows the principal part of the foundation structure which concerns on preferable one Embodiment of this embodiment. It is a fragmentary perspective view explaining the structure of a base layer.

Explanation of symbols

10 Building foundations on soft ground 11 Residential buildings (buildings)
11a Foundation part of a residential building 12 Basement layer (planar solidified body by surface layer improvement method)
12a Center part of base layer 13 Support pile (columnar solidified body by columnar improvement method)
14 Solid foundation 14a Central portion 15 of solid foundation 15 Clearance 16 between foundation layer and solid foundation Adjusting sand 17 Rising wall

Claims (3)

A basic structure of a building that allows the inclination of the building to be corrected when a subsidence occurs in a building constructed above soft ground,
A basement layer provided on a surface layer portion of the foundation ground of the building, a plurality of support piles provided in the foundation ground to support a central portion of the basement layer, and a layer placed above the basement layer Consisting of the basics,
In the base layer, the central portion supported by the support pile is raised one step higher, the central portion of the solid foundation is placed, and between the base layer and the solid foundation around the central portion. In the gap, the basic structure of the building in soft ground filled with adjustment sand.   The foundation of a building in soft ground according to claim 1, wherein the base layer is a planar solid body formed by a surface layer improvement method, and the support pile is a columnar solid body formed by a columnar method. Construction. When uneven settlement occurs in the building, the adjustment sand between the base layer and the solid foundation at the heightened portion with the central portion as a fulcrum is removed, and the base layer and the solid foundation at the lowered portion are removed. The foundation structure of the building in the soft ground according to claim 1 or 2, wherein the inclination of the building is adjusted by adding adjustment sand between the two.

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