JP2010196346A - Support structure and construction method of concrete floor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support structure and a construction method of a concrete floor of high quality suppressing the occurrence of settlement and unevenness of the concrete floor 11 and improving construction efficiency in constructing the concrete floor 11 to reduce construction cost. <P>SOLUTION: The existing soft ground G1 is provided with a floating support body 22 including a settlement restraining pile 221 driven into the soft ground G1 and not reaching the lower layer support ground G2, and the concrete floor 11 is supported on the soft ground G1 and the floating support body 22 through a load transmission layer 21. A vertical load W from the concrete floor 11 is thereby transmitted to the floating support body 22 including the settlement restraining pile 221 through the load transmission layer 21 and transmitted to the soft ground G1 through the load transmission layer 21 and the floating support body 22. The occurrence of unevenness of the concrete floor 11 due to excessive bearing power is thereby absorbed effectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a support structure between concrete soils and a construction method in a building constructed on soft ground and having a first floor made of concrete soil.

  For example, in the construction of buildings such as logistics facilities, warehouses, factories, stores, etc., where the ground floor is made of concrete soil, the compaction that causes inconvenience in use in the concrete soil (first floor) due to the soft layer existing in the ground If subsidence is expected, in order to suppress the subsidence, an interstitial pile that only bears the load between the concrete soils or between the concrete soils and the object loaded on the concrete soils is placed under the concrete soils. It has been known.

  FIG. 11 is a cross-sectional view showing a conventional support structure between concrete soils by a soil receiving pile, that is, reference numeral G is an existing ground composed of a soft ground G1 and a solid supporting ground G2 below it, and 21 is an existing ground G (soft Improved ground formed on the ground G1) by mixing with a solidified material, 101 is a ground receiving pile that reaches the supporting ground G2 in the soft ground G1 from the improved ground 21, and 102 is cast on the improved ground 21 A concrete soil bonded to a pile head of the receiving pile 101. A similar technique is disclosed in Patent Document 1 below.

JP 2006-207118 A

  However, according to the prior art, since the allowable bearing force of the interstitial pile 101 reaching the supporting ground G2 is too large, the soft viscous soil layer in the soft ground G1 is consolidated by the load from above, and the consolidated subsidence G1a As a result, the concrete soil 102 sinks at a position away from the pile head 101a of the soil receiving pile 101, whereas the concrete soil 102 does not sink at the position supported by the soil receiving pile 101. For this reason, there has been a risk that the relative “push-up” may cause unevenness in the concrete soil 102 and hinder use.

  Therefore, in order to employ the concrete soil 102 supported by the soil receiving pile 101, the consolidation of the consolidated subsidence G1a caused by the load of the concrete soil 102, the load of the load loaded on the concrete soil 102 or the load of the improved ground 21 is achieved. It is necessary to predict the amount (subsidence amount) with high accuracy or to make the concrete soil 102 a thick slab so that there is no problem even if a relative “push-up” occurs due to subsidence. However, when the slab is thickened, not only the amount of settlement is increased, but also the construction cost is increased, and the rigidity is increased, so that there is a problem that even a slight settlement tends to cause cracks.

  Moreover, before constructing the improved ground 21 on the existing ground G, as shown in FIG. 12, the head 101 a of the soil receiving pile 101 is in a state of protruding from the surface GL of the existing ground G. Large-scale heavy machinery cannot be used for embankment work for building construction, mixing and stirring of consolidated materials, rolling compaction, compaction, etc., or even when used, the efficiency is remarkably reduced or the quality of the improved ground 21 May decrease. For this reason, the construction of the improved ground 21 is forced to use a relatively small heavy machine or a rolling / compacting machine, and there is a problem that construction efficiency does not increase.

  The present invention has been made in view of the above points, and its technical problem is to suppress the occurrence of subsidence and unevenness between concrete soils and to construct the concrete soil space 11. It is to provide a support structure and a construction method for high quality concrete soil by improving construction efficiency and reducing construction cost.

  As a means for effectively solving the technical problem described above, the support structure between concrete soils according to the invention of claim 1 is placed on the existing soft ground, and on the lower support ground. A floating support including a settlement suppression pile that does not reach is provided, and the concrete soil is supported on the soft ground and the floating support via a load transmission layer. For this reason, the vertical load from the concrete soil is transmitted to the floating support including the settlement restraint pile through the load transmission layer, and is transmitted to the soft ground through the load transmission layer and the floating support. Settling is effectively suppressed. The load transmission layer transmits a vertical load from between the concrete soil while diffusing in the plane direction, and has an action of making the settlement uniform.

  According to a second aspect of the present invention, there is provided a support structure between concrete soils according to the first aspect of the present invention. The plane projected area of the load receiving plate is larger than the pile diameter of the settlement restraint pile.

  In the support structure between concrete soils according to the invention of claim 3, the levitation support body described in claim 1 includes an extension portion formed on a pile head of the settlement suppression pile, and the extension portion has a plane projection area. A cone or polygonal pyramid that is larger toward the upper side and larger than the pile diameter of the main body portion of the settlement suppression pile is formed.

  In the support structure between concrete soils according to the invention of claim 4, the load transmission layer described in claim 1 is composed of embankment or crushed stone layer by improved ground.

  In the support structure between concrete soils according to the invention of claim 5, the load transmission layer described in claim 1 is made of an elastically deformable cushioning material.

  In the construction method between concrete soils according to the invention of claim 6, in order to construct the support structure between concrete soils according to the invention of claim 1, a settlement suppression pile that does not reach the underlying support ground is placed on the existing soft ground. And a step of constructing the floating support including the settlement restraining pile, a step of forming a load transmission layer on the soft ground and the floating support, and a step of constructing the concrete soil on the load transmission layer, , Are provided.

  According to the support structure between the concrete soils according to the invention of claim 1, even if a vertical load that would cause a subsidence that has conventionally been a problem in use between the concrete soils is applied, this load is applied to the load transmission layer and the floating support. Therefore, the subsidence is effectively suppressed and the occurrence of unevenness due to relative “push-up” is also suppressed. And it is not necessary to make a concrete slab into a thick slab for this, and construction cost can be reduced.

  According to the support structure between concrete soils according to the invention of claim 2 or 3, since the support force of the levitating support body against a vertical load is improved, the occurrence of subsidence and resulting unevenness can be more effectively suppressed.

  According to the support structure between the concrete soils according to the fourth aspect of the present invention, the occurrence of unevenness can be effectively absorbed by the appropriate deformability of the load transmission layer composed of the improved ground, embankment, or crushed stone layer.

  According to the support structure between the concrete soils according to the fifth aspect of the present invention, the occurrence of unevenness can be effectively absorbed by the moderate deformability of the load transmission layer made of the cushioning material.

  According to the construction method between concrete soils according to the invention of claim 6, since the subsidence suppression pile placed on the existing soft ground does not become an obstacle when constructing the load transmission layer with improved ground or embankment, large heavy machinery In addition, it is possible to efficiently perform construction using a large-sized rolling compaction and compaction machine. As a result, it is possible to reduce the cost of construction and to build a high-quality support structure between concrete soils.

It is sectional drawing which shows the 1st form of the support structure between the concrete soils concerning this invention. It is sectional drawing which shows the construction process of the support structure of a 1st form. In 1st form, it is sectional drawing which shows the example which formed the improved ground in the surface layer part of the existing ground. It is a diagram which shows the effect by the support structure of the Example of this invention compared with the conventional support structure (Comparative Example 1, Comparative Example 2). It is sectional drawing which shows the support structure of an Example, the comparative example 1, and the comparative example 2. FIG. It is sectional drawing which shows the 2nd form of the support structure between the concrete soils concerning this invention. It is sectional drawing which shows the 3rd form of the support structure between the concrete soils concerning this invention. It is sectional drawing which shows the 4th form of the support structure between the concrete soils concerning this invention. It is sectional drawing which shows the construction example which applied the support structure between the concrete soils concerning this invention to the construction of the building which has a concrete soil space. FIG. 10 is a plan view showing a load receiving plate in FIG. 9. It is sectional drawing which shows the support structure between the conventional concrete soil by a soil receiving pile. It is sectional drawing which shows the process of constructing the support structure between the conventional concrete soil.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. First, FIG. 1 is a sectional view showing a first embodiment of a support structure between concrete soils according to the present invention.

  In FIG. 1, reference numeral G is an existing ground composed of a soft ground G <b> 1 and a solid supporting ground G <b> 2 below it. The soft ground G1 is provided with a levitation support body 22 composed of a subsidence suppression pile 221 placed vertically on the soft ground G1, and an improved ground 21 having an appropriate layer thickness is provided on the soft ground G1 and the levitation support body 22. The concrete soil space 11 is constructed on the improved ground 21.

  The improved ground 21 is a load transmission layer according to claim 1, and is mixed with a solidified material such as cement to a soil material, mixed and stirred, and rolled to compress the concrete soil 11 and stored on it. It expresses a supporting force against a vertical load due to the weight of an object or the like. Therefore, this improved ground 21 has the effect | action which transmits the vertical load W from the concrete soil 11 to the soft ground G1 from the bottom face 21a, diffusing in the plane direction, and equalizes the consolidation settlement of the soft ground G1.

  In addition, as the settlement suppression pile 221, it is possible to suitably use a ready-made pile, a cast-in-place pile, or a soil cement column. The pile head of the settlement restraining pile 221 is located at or near the bottom surface 21a of the improved ground 21, and has a length at which the lower end does not reach the support ground G2.

  In the construction of the concrete soil 11 having the above-described configuration, as shown in FIG. 2, the floating support 22 is first constructed by placing a settlement suppression pile 221 on the soft ground G1 in the existing ground G. At this time, the settlement suppression pile 221 is placed so that the pile head does not protrude from the surface GL of the existing ground G.

  Next, the earth material generated by the placement of subsidence suppression piles 221 and the construction of foundation work is piled up on the existing ground G (soft ground G1), the solidified material is added, mixed and stirred, and rolled. Thus, the improved ground 21 is constructed. At this time, since the pile head of the settlement suppression pile 221 as the levitation support body 22 does not protrude from the surface GL of the existing ground G (soft ground G1), a heavy machine is used to raise soil materials and the like to construct the improved ground 21 It is not an obstacle to mixing and stirring the solidified material and rolling it, and large heavy machinery and large rolling and compacting machines can run freely vertically and horizontally. For this reason, the improved ground 21 can be constructed efficiently, and as a result, the construction cost can be reduced and the improved ground 21 with high quality can be constructed.

  When the construction of the improved ground 21 is finished, the concrete soil 11 is constructed on the improved ground 21 by a normal method.

  In addition, you may replace the improved ground 21 with what consists of the embankment ground which mixed crushed stone, regenerated crushed stone, or a crushed stone layer. Further, the improved ground 21 may be formed on the surface layer portion of the existing ground G as shown in FIG. 3, but in the construction in this case, the head is improved when the subsidence suppression pile 221 is placed. Drive in so that it is located at the depth that will be the bottom of the ground.

  According to the above-described embodiment, the vertical load W resulting from the sum of the load between the concrete soil 11 and the load of the load loaded on the concrete soil 11 is set via the improved ground 21 serving as a load transmission layer. It is transmitted to (floating support 22) and soft ground G1. And since the resistance force F which becomes large toward the lower end side of the settlement subsidence pile 221 is generated between the settlement subsidence pile 221 and the soft ground G1, the vertical load W has conventionally caused subsidence that is a problem in use in the concrete soil 11. Even if it is large, subsidence is effectively suppressed by the resistance force F of the subsidence suppression pile 221, in other words, the consolidated subsidence G1a generated by the consolidation of the soft viscous soil layer in the soft ground G1. Consolidation (settlement) is reduced.

  In addition, since the settlement suppression pile 221 does not reach the solid support ground G2 below the soft ground G1, a certain amount of settlement is allowed, and therefore, the relative “protrusion” of the concrete soil 11 due to excessive support force is allowed. “Up” is suppressed. Further, the load transmission layer made of the improved ground 21 (or a crushed stone layer or the like) has a buffering property that allows a certain degree of deformation between the settlement suppression pile 221 and the concrete soil 11, and the vertical load from the concrete soil 11. Since it has the action of transmitting W while diffusing in the plane direction to make the consolidation settlement of the soft ground G1 uniform, the occurrence of unevenness in the concrete soil 11 is effectively absorbed. Therefore, it is not necessary to make the concrete soil 11 into a thick slab, and the construction cost can be reduced.

  Furthermore, since the settlement suppression pile 221 improves the horizontal shearing force of the soft ground G1, the liquefaction phenomenon when an earthquake occurs can be effectively suppressed.

  In addition, since the resistance force F by the friction of the settlement suppression pile 221 becomes larger as the length of the settlement suppression pile 221 is longer, it is appropriately set in consideration of the predicted consolidation settlement amount.

  FIG. 4 is a diagram showing the effect of the support structure of the present invention in comparison with a conventional support structure. In the embodiment in this diagram, as shown in FIG. 5A, the concrete soil 11 is supported on the soft ground G1 and the subsidence suppression pile 221 via the improved ground 21, that is, similarly to the above-described form. As shown in FIG. 5 (B), the comparative example 1 in the diagram of FIG. 4 is configured such that a part of the concrete soil 11 is in contact with and supported by the pile heads of the settlement suppression piles 221. 11 described in FIG. 11, and Comparative Example 2 in the diagram of FIG. 4 has a structure in which the concrete soil 11 is not supported by the settlement suppression pile 221 as shown in FIG. 5C. It is a thing.

  From the diagram of FIG. 4, in Comparative Example 1 in which the concrete soil 11 is directly supported by the settlement suppression pile 221, the support force by the settlement suppression pile 221 is too large, and relative to the concrete soil 11 as the surrounding settlement occurs. In the comparative example 2 where the large unevenness occurs due to the thrust and is not supported by the settlement suppression pile 221, a large settlement occurs between the concrete soils 11, whereas according to the example, the settlement is reduced as compared with the comparative example 2. In addition, it can be seen that uneven landing due to relative thrust is also prevented.

  FIG. 6 is a sectional view showing a second embodiment of the support structure between concrete soils according to the present invention. In the second embodiment, the difference from the first embodiment shown in FIG. 1 described above is that the floating support 22 is installed on the soft ground G1 (between the soft ground G1 and the improved ground 21). The load receiving plate 222 is included. The load receiving plate 222 has a plane projection area sufficiently larger than the pile diameter of the settlement restraining pile 221, and is made of a precast concrete plate, cast-in-place concrete, or a rust-proof iron plate. And the like can be suitably employed, and are preferably coupled to the pile head of the settlement restraining pile 221. Other parts can be basically configured in the same manner as in FIG.

  Therefore, according to the second embodiment, the vertical load W resulting from the sum of the load between the concrete soil 11 and the load of the load loaded on the concrete soil 11 is transferred from the improved ground 21 which is a load transmission layer to the load receiving plate 222. Therefore, the vertical load W can be supported with a larger area.

  FIG. 7 is a cross-sectional view showing a third form of the support structure between concrete soils according to the present invention. In the third embodiment, the difference from the first embodiment shown in FIG. 1 described above is that the levitation support 22 includes an extended portion 223 formed on the pile head of the settlement restraining pile 221. . The extended portion 223 has a conical shape or a polygonal pyramid shape having a larger planar projection area toward the upper side and larger than a pile diameter of the settlement suppression pile 221. Other parts can be basically configured in the same manner as in FIG.

  Therefore, according to the third embodiment, the vertical load W resulting from the sum of the load between the concrete soil 11 and the load of the load loaded on the concrete soil 11 is caused by the extension portion 223 from the improved ground 21 which is a load transmission layer. Therefore, the vertical load W can be supported by a larger area than the pile head of the settlement suppression pile 221. Moreover, since the tapered side surface 223a of the extended portion 223 acts to expand the surrounding ground due to the vertical load transmitted to the extended portion 223, the resistance to subsidence is improved.

  FIG. 8: is sectional drawing which shows the 4th form of the support structure between the concrete soils concerning this invention. In the fourth embodiment, a difference from the first embodiment shown in FIG. 1 described above is that the load transmission layer interposed between the concrete soil 11 and the existing ground G (soft ground G1) is an improved ground. 21 and the buffer material 23. The cushioning material 23 is provided directly above the installation position of the levitation support 22 (subsidence suppression pile 221), and is made of an elastically deformable material such as a rubber material, a synthetic resin material having rubber-like elasticity, or asphalt. It is. Other parts can be basically configured in the same manner as in FIG.

  Therefore, according to the fourth embodiment, the vertical load W resulting from the sum of the load of the concrete soil 11 and the load of the load loaded on the concrete soil 11 is the improved ground 21 around the installation position of the settlement suppression pile 221. Is transmitted to the soft ground G <b> 1, while being transmitted to the settlement suppression pile 221 via the cushioning material 23 at the installation position of the settlement suppression pile 221. For this reason, since the supporting force with respect to the vertical load W is relieved by the deformation characteristics of the buffer material 23, the occurrence of unevenness due to the relative push-up of the settlement suppression pile 221 accompanying the settlement around the installation position of the settlement suppression pile 221. Can be absorbed effectively.

  In addition, the levitation support body 22 shown in FIG. 8 also has a configuration in which the load receiving plate 222 as shown in FIG. 6 and the extended portion 223 as shown in FIG. be able to.

  Next, FIG. 9 is a sectional view showing a construction example in which the support structure between concrete soils according to the present invention is applied to construction of a building having a concrete soil space, and FIG. 10 is a plan view showing a load receiving plate in FIG. .

  In FIG. 9, reference numeral 10 is a building used as, for example, a distribution facility, a warehouse, a factory, a store, etc., and is built on the soft ground G <b> 1 and the first floor is made of concrete soil 11.

  The pillar 12 of the building 10 is supported by a support pile 13 placed on the existing ground G through a foundation beam 14 made of reinforced concrete so as to reach a solid support ground G2 below the soft ground G1. 11 is constructed on the soft ground G1 through the improved ground 21 or the crushed stone layer.

  The soft ground G1 in the existing ground G is provided with a levitating support 22 located between the support positions of the building 10 by the support pile 13 and the foundation beam 14. The levitating support 22 is vertically placed on the soft ground G1 and the lower end of the subsidence suppression pile 221, the lower end of which does not reach the support ground G2, and the top of the subsidence suppression pile 221 is installed on the soft ground G1. As shown in FIG. 10, the pile heads of the four settlement restraining piles 221 are coupled to the vicinity of the four corners of each of the square load receiving plates 222. .

  In the construction of the building 10 described above, first, in parallel with the foundation work such as the placement of the support pile 13 on the existing ground G and the construction of the foundation beam 14 using reinforced concrete, the settlement suppression pile 221 is placed on the soft ground G1. The floating support body 22 is installed such that the load receiving plate 222 is installed on the soft ground G1 and coupled to the pile head of the settlement restraining pile 221.

  Next, the earth material generated by the placement of the support pile 13 and the subsidence suppression pile 221 and the construction of the foundation beam 14 is piled up on the existing ground G (soft ground G1), and the solidified material is added and mixed and stirred. Then, the improved ground 21 as a load transmission layer is constructed by rolling. At this time, since the floating support 22 does not protrude from the surface GL of the existing ground G in the area partitioned by the foundation beam 14, the earthen material or the like is piled up by heavy machinery, or the solidified material is mixed and stirred to perform rolling. Large heavy machinery and large compaction and compaction machines can run freely vertically and horizontally. For this reason, mixing agitation and rolling can be performed efficiently. As a result, the construction cost can be reduced and the improved ground 21 with high quality can be constructed.

  When the construction of the improved ground 21 is finished, the concrete soil 11 on the first floor is constructed on the improved ground 21 by a normal method. Subsequent construction of the building 10 is performed in the same manner as usual.

According to the building 10 described above, the vertical load W ₁ resulting from the sum of the load of the concrete soil 11 and the load of the load loaded on the concrete soil 11 is due to the support pile 13 and the foundation beam 14 shown in FIG. In the vicinity of the support position, it is transmitted to the foundation beam 14 and the support pile 13 by the rigidity of the concrete soil 11.

On the other hand, in the position away from the support position by the support piles 13 and footing beams 14, and the load of the concrete earth floor 11, vertical load W ₂ by the sum of the load of the loading material to be stacked on the concrete dirt floor 11, load transfer layer It is transmitted to the load receiving plate 222 of the levitation support 22 through the improved ground 21, and further transmitted from the settlement suppression pile 221 of the levitation support 22 to the existing ground G (soft ground G1). For this reason, even if the vertical load W ₂ is large in the past, which causes a settlement that causes a problem in use in the concrete soil 11, the settlement is effectively caused by the resistance force generated between the floating support 22 and the soft ground G 1. In addition, the occurrence of unevenness in the concrete soil 11 due to relative “push-up” is effectively absorbed.

10 Building 11 Concrete soil 12 Column 13 Support pile 14 Foundation beam 21 Improved ground (load transmission layer)
21a Bottom surface 22 Levitation support body 23 Buffer material 221 Settling suppression pile 222 Load receiving plate 223 Expansion part G Existing ground G1 Soft ground G1a Consolidation subsidence G2 Support ground

Claims (6)

  The existing soft ground is provided with a levitation support including a settlement restraining pile that is placed on the soft ground and does not reach the underlying support ground, and a load transmission layer is provided on the soft ground and the levitation support. Support structure between concrete soils, characterized by being supported between concrete soils.   The levitation support body is provided on a soft ground and includes a load receiving plate supported by a pile head of a settlement subsidence pile, and a plane projection area of the load support plate is larger than a pile diameter of the settlement subsidence pile. The support structure between concrete soils of Claim 1.   The levitation support has an extension formed on the pile head of the settlement restraining pile, and this extension has a cone or polygonal pyramid shape having a larger plane projection area on the upper side and larger than the pile diameter of the body portion of the settlement restraining pile. The supporting structure between concrete soils according to claim 1, wherein:   The support structure between concrete soils according to claim 1, wherein the load transmission layer is composed of an embankment made of improved ground or a crushed stone layer.   The support structure between concrete soils according to claim 1, wherein the load transmission layer is made of an elastically deformable cushioning material.   In order to construct a support structure between concrete soils according to the invention of claim 1, a subsidence suppression pile that does not reach the underlying support ground is placed on an existing soft ground, and a floating support including this subsidence suppression pile is constructed. A construction method between concrete soils, comprising: a step; a step of forming a load transmission layer on the soft ground and the floating support; and a step of constructing a concrete soil between the load transmission layers.

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