JP2018017104A - Composite body of earth structure and concrete structure and construction method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite body of an earth structure and a concrete structure and a construction method thereof, capable of realizing efficient construction and firm support of the concrete structure, by establishing the earth structure being a ground improvement body for performing a plurality of functions.SOLUTION: A construction method of a composite body of an earth structure and a concrete structure comprises: a first step of agitating and mixing an original ground G1 and a solidification material to establish column row ground improvement bodies 1A and 1B, and juxtaposing and establishing the column row ground improvement bodies 1A and 1B to establish a gravity type retaining wall-shaped earth structure 10; a second step of installing the concrete structure on a B part with the B part of the earth structure 10 as a support body 3 of the concrete structure while executing earth retaining with an A part of the earth structure 10 as an earth retaining wall 2; and a third step of constructing the composite body of the earth structure and the concrete structure by backfilling beside and above the concrete structure.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a composite of a soil structure and a concrete structure and a construction method thereof.

  When constructing a concrete structure on soft ground, there are many cases in which this soft ground is improved by various methods to improve the ground to support the concrete structure.

  As this ground improvement method, when the soft ground is shallower than about 2 m, there is a surface improvement method in which the soft ground and the solidified material are mixed by stirring to create an improved material and then compacted with heavy machinery or rollers. In the case where the depth is 2 m or more, for example about 10 m or more, the solidified material is injected into the ground from the tip while stirring the ground with a stirring blade, and the ground and the solidified material are stirred and mixed to form a columnar ground improvement body. There is a deep layer improvement method (deep layer mixed processing method).

  Here, in Patent Document 1, the ground and the solidified material are agitated and mixed to create a gravitational retaining wall-like earth structure in the ground outside the excavation area, and the earth structure that is the improved ground is held in place. An earth retaining method using a gravity retaining wall-like soil structure is disclosed in which the excavation area is excavated while functioning as a wall to prevent the soil surrounding the excavation area from collapsing with the earth structure.

JP-A-2-252817

  According to the earth retaining method using the gravitational retaining wall-shaped soil structure described in Patent Document 1, the workability is good regardless of the size of the excavation area, and the expected safety is achieved even when the excavation depth is large. It can be easily secured.

  However, the gravity-type retaining wall-like soil structure described in Patent Document 1 has only a function as a retaining wall, and can only be expected to prevent surrounding ground collapse during excavation in the excavation area.

  The present invention has been made in view of the above-described problems, and by realizing a soil structure that is a ground improvement body having a plurality of functions, it is possible to achieve efficient construction and support of a solid concrete structure. An object of the present invention is to provide a composite of a soil structure and a concrete structure, and a construction method thereof.

  In order to achieve the above object, the method for constructing a composite of an earth structure and a concrete structure according to the present invention is to create a columnar ground improvement body by stirring and mixing the original ground and the solidified material, and the columnar ground improvement body The first step of creating a gravitational retaining wall-shaped earth structure by arranging the earth walls side by side, the part B of the earth structure is concreted while retaining the earth using the part A of the earth structure as the earth retaining wall A second step of installing the concrete structure on the part B of the earth structure as a support for the structure, backfilling the side and upper side of the concrete structure, and the earth structure and the concrete structure; It consists of a third step of constructing a composite of objects.

  The method for constructing a composite structure of a soil structure and a concrete structure according to the present invention is a method of forming a gravity retaining wall-like soil structure by arranging columnar ground improvement bodies, and using the A part of the soil structure as a retaining wall. By installing the concrete structure on the B part of the earth structure using the B part of the earth structure as a support for the concrete structure while fastening, the function as the earth retaining wall on the earth structure and the concrete structure It is a construction method that has a function as a support for an object.

  Here, the “gravity type retaining wall-like earth structure” refers to a structure in which a plurality of columnar ground improvement bodies provided together are in a lump and resists earth pressure. This means that the earth retaining wall directly resists earth pressure, but the earth structure as a whole is a stable structure that does not slide or fall over the earth pressure. In addition, “A part” and “B part” mean that both are part of the earth structure and are different from each other, and both A part and B part are within the earth structure. There are multiple locations.

  First of all, in the first step, a plurality of columnar ground improvement bodies are constructed so as to be a gravitational retaining wall-like soil structure, so that the plurality of columnar ground improvement bodies are regarded as a lump structure. It is possible to eliminate the provision of, for example, a steel core for each columnar ground improvement body. In the conventional deep mixing method for retaining walls, a steel core is a constituent element because it is not based on such a design concept.

  In the first step, in the creation of the earth structure, for example, a deep mixing process is performed from the original ground surface, and a plurality of columnar ground improvement bodies are arranged side by side to create a part (A part) that becomes a retaining wall. It is preferable to construct the entire earth structure by continuously constructing a portion (B portion) that becomes a support of the concrete structure.

  As for the earth structure, a part (A part) is a retaining wall, the other part (B part) is a support body of a concrete structure, and it becomes a gravitational retaining wall-like earth structure as a whole. Yes. For example, the earth structure is made by setting the upper end level of the support of the concrete structure that is the other part of the earth structure to be lower than the upper end level of the earth retaining wall that is a part of the earth structure. The concrete structure can be constructed on the support of the inner concrete structure that is earthed by the earth retaining wall that is a part of the object.

  Therefore, in the second step, the concrete structure is placed on the support of the concrete structure which is the B part of the earth structure that has already been created, while retaining the earth retaining wall of the A part of the earth structure. Since it can be constructed, it is possible to significantly reduce the entire process from the earth retaining to the construction of the concrete structure as compared with the conventional construction method.

  Also, for example, when there is no earth retaining wall consisting of a part of such a soil structure, when trying to create a support for a concrete structure, an excavation slope with a predetermined gradient from the support for the concrete structure. However, there is a problem that the effective space is reduced by this excavation slope, in other words, a problem that the construction area is widened.

  However, in the construction method of the present invention, the gravitational retaining wall-like earth structure created in the first step is a continuum of a part that serves as a retaining wall and a part that serves as a support for a concrete structure. From the above, it is possible to construct a concrete structure on the side (near) the retaining wall. As a result, it is possible to construct a concrete structure having a predetermined size within a narrow construction area.

  In addition, a part of the gravitational retaining wall-like earth structure is used as a retaining wall, and construction can be performed inside the retaining wall, which leads to securing construction safety.

  Once the entire earth structure has been constructed, the excavation area inside the retaining wall is excavated with the heavy equipment on the back side of the part A that will be the retaining wall of the earth structure, and the concrete in the part B of the earth structure Expose the top edge of the support of the structure.

  After constructing the concrete structure on the top edge of the exposed concrete structure support, the third step is to backfill the concrete structure sideways and upwards, thereby combining the earth structure and the concrete structure. The body is constructed.

  Here, the construction of the concrete structure may be a method in which the concrete structure is sequentially constructed upward from the foundation on the support inside the retaining wall, or a precast produced in a factory or the like. A method of installing the structure on the support with a heavy machine may be used.

  In the first step, it is preferable that at least the lower end of the columnar ground improvement body constituting the part B of the earth structure reaches the support layer of the original ground.

  Among the columnar ground improvement bodies that constitute the earth structure, the bottom of the columnar ground improvement body that constitutes the support for the concrete structure is allowed to reach the support layer, thereby preventing problems such as settlement of the concrete structure. The concrete structure can be firmly supported without causing it.

  Further, as an embodiment of the method for constructing a composite structure of a soil structure and a concrete structure according to the present invention, the concrete structure is a portal culvert, and in the first step, a biped of the portal culvert is attached. In the second step, the soil structure is formed at the corresponding position, and in the second step, the gate-type culvert bipod is installed at the B portion of each soil structure.

  In the present embodiment, for example, two caster-type culverts made of precast or on-site construction are respectively installed on the B section at two locations, and backfilling is performed laterally and upwardly of the portal-type culvert. .

  By installing the portal culvert, it is possible to construct a three-dimensional intersection road with the inside of the portal culvert as a road tunnel and the upper floor of the portal culvert as a road bridge.

  When constructing this three-dimensional crossing road, by applying the construction method of the present invention, prior to constructing the upper road by backfilling the side and upper side of the portal culvert, the inside of the portal culvert It will be possible to use the road immediately. For example, when a highway is constructed above the portal culvert and an ordinary road is constructed inside the portal culvert, the operation of the ordinary road can be started prior to the operation of the expressway.

  Further, the present invention extends to a composite of a soil structure and a concrete structure, and this composite is a gravitational retaining wall provided with a plurality of columnar ground improvement bodies made of a solid ground and a solidified material. A soil structure, wherein part A of the soil structure is a retaining wall, part B of the soil structure is a support for a concrete structure, and the soil structure A concrete structure disposed on the portion B, a side of the concrete structure, and an upper backfill soil are provided.

  In the composite of a soil structure and a concrete structure according to the present invention, a gravity retaining wall-like soil structure, which is a component thereof, has an A part that serves as a retaining wall and a B part that serves as a support for the concrete structure. Therefore, the concrete structure can be constructed on the support of the concrete structure while retaining the earth with the retaining wall.

  Here, also in this composite body, it is preferable that the lower end of the columnar ground improvement body constituting the part B of the earth structure reaches the support layer of the original ground.

  Further, as an embodiment of a composite of a soil structure and a concrete structure, the concrete structure is a portal culvert, and the soil structure is disposed at a position corresponding to a bipod of the portal culvert. It can be mentioned that the gate-shaped culvert bipod is disposed in the B part of the earth structure.

  According to the composite structure of a soil structure and a concrete structure of the present invention and its construction method, the gravity retaining wall-shaped soil structure to be constructed functions as a retaining wall and functions as a support for the concrete structure. Therefore, by installing the concrete structure on the support of the concrete structure while retaining the earth with the retaining wall, the composite of the earth structure and the concrete structure can be efficiently performed. It is possible to construct a composite in which a concrete structure is firmly supported.

It is the longitudinal cross-sectional view explaining the 1st step of the construction method of this invention. It is an II-II arrow line view of FIG. It is the longitudinal cross-sectional view explaining the 2nd step of the construction method of this invention. It is the longitudinal cross-sectional view explaining the 2nd step of the construction method following FIG. It is the longitudinal cross-sectional view explaining the 3rd step of the construction method of this invention, Comprising: It is the figure which showed the composite_body | complex of the earth structure and concrete structure of this invention. It is a figure explaining the situation which is operating a three-dimensional intersection road.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a composite structure of a soil structure and a concrete structure and a construction method thereof according to the present invention will be described below with reference to the drawings. In the illustrated example, the concrete structure is a gate-type culvert provided on a three-dimensional intersection road, but it is needless to say that the concrete structure is not limited to the gate-type culvert.

(Embodiment of composite structure of earth structure and concrete structure and its construction method)
FIG. 1 is a longitudinal sectional view illustrating the first step of the construction method of the present invention, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIGS. It is a longitudinal cross-sectional view explaining the 2nd step. FIG. 5 is a longitudinal sectional view explaining the third step of the construction method of the present invention, showing a composite of the earth structure and the concrete structure of the present invention, and FIG. 6 is a three-dimensional intersection. It is a figure explaining the situation which is using the road.

  A solidification material (improvement material) plant (not shown) is installed on the ground surface, a stirring blade mounted on a base machine (not shown) is rotationally pressed into the original ground G1, and the solidification material is loosened while loosening the original ground G1 with the stirring blade. Is injected into the ground, and the original ground G1 and the solidified material are stirred and mixed to form the columnar ground improved bodies 1A and 1B shown in FIGS.

  In the illustrated example, the original ground G1 is a relatively soft ground, and a hard support layer G2 exists at a predetermined depth of the original ground G1.

  A plurality of columnar ground improvement bodies 1A not reaching the support layer G2 constitute the retaining wall 2, and a plurality of columnar ground improvement bodies 1B reaching the support layer G2 is a support 3 of a concrete structure. The earth retaining wall 2 and the support body 3 constitute an earth structure 10 having a gravitational retaining wall shape.

  That is, the earth structure 10 has a part (A part) of the earth retaining wall 2 and the other part (B part) is a support 3 of the concrete structure, and as a whole is a gravitational retaining wall-like earth. It is a structure 10.

  As will be described later, the columnar ground improvement body 1A constituting the retaining wall 2 is not necessarily required to reach the support layer G2 because it only needs to resist earth pressure. On the other hand, it is desirable that the columnar ground improvement body 1B constituting the support 3 for the concrete structure should reach the support layer G2 in order to support the load of the concrete structure and prevent subsidence. Even in this form, the columnar ground improvement body 1B reaches the support layer G2. However, considering the earth pressure resistance, the sliding stability, etc. of the earth structure 10, the columnar ground improvement body 1A may reach the support layer G2 in the same manner as the columnar ground improvement body 1B as necessary. Good.

  In the embodiment shown in FIGS. 1 and 2, two gravitational retaining wall-like earth structures 10 in which the retaining wall 2 and the support 3 are integrated are formed at intervals (hereinafter, the first). Step).

  Next, as shown in FIG. 3, the original ground G1 between the two earth structures 10 is excavated. More specifically, a heavy machine such as a clam shell (not shown) on the back surface of the retaining wall 2 or a heavy machine such as a backhoe (not shown) suspended in the excavation area is used in combination. A temporary pier or the like is constructed between the base retaining wall 2 and excavation is performed by using a heavy machine on the temporary pier.

  As shown in FIG. 3, the earth retaining wall 2 constituting the earth structure 10 directly resists the main earth pressure Pa, and excavation is performed while preventing the collapse of the back ground.

  By performing this excavation until the top end face 3a of the support 3 constituting the earth structure 10 is exposed, an excavation region E is formed between the two earth structures 10.

  Here, the passive earth pressure Pp is acting from the front surface of the support body 3, and regarding the sliding stability of the earth structure 10 by the main earth pressure Pa, this passive earth pressure Pp, the earth structure 10 and the ground The value obtained by dividing the resultant force with the frictional resistance force F by the sliding force resulting from the main earth pressure Pa satisfies a predetermined safety factor or more.

  When the excavation area E is formed, a portal culvert 20 that is a concrete structure is installed on the support 3 as shown in FIG.

  More specifically, the two legs 20 a constituting the portal culvert 20 are installed on the support 3 of the corresponding earth structure 10. Here, the installation of the portal culvert 20 includes a method of suspending and installing the precast portal culvert 20 with heavy machinery, and a method of constructing the portal culvert 20 directly on site, taking into consideration the construction period and cost. One of the methods is selected (the second step).

  As shown in FIG. 4, the load W that directly acts on the support 3 from each leg 20 a is dispersed in the support 3 (dispersion angle 30 ° in the illustrated example), and the dispersed load W is reduced by load distribution. 'Is loaded on the support layer G2, and this dispersion load W' is supported by the support layer G2. In addition, finally, the total dispersed load including up to the embankment load is loaded on the support layer G2, and this is supported by the support layer G2.

  When the installation of the portal culvert 20 is completed, as shown in FIG. 5, the portal culvert 20 is backfilled laterally and upward (formation of the backfill soil 30), and the earth structure 10 and the concrete structure 20 are The composite 100 is constructed.

  A roadbed 40 is constructed below the inner space 20b of the portal culvert 20 to form a road tunnel, which is used as a general road. The construction of the roadbed 40 and the use of the road may be performed prior to backfilling after the portal culvert 20 is installed.

  Furthermore, as shown in FIG. 6, the roadbed 50 is also constructed on the backfill 30 above the portal culvert 20 and used as a general road or a highway.

  According to the construction method of the soil structure-concrete structure composite 100 shown in the figure, the gravitational retaining wall-like earth structure 10 to be formed has both the retaining wall 2 and the support 3 of the concrete structure. Therefore, by installing the concrete structure 20 on the support 3 of the concrete structure while retaining the earth with the retaining wall 2, the composite 100 of the earth structure and the concrete structure can be efficiently performed. The construction period can be greatly shortened.

  Further, since the earth retaining wall 2 is a constituent element of the earth structure 10, it can be regarded as a part of the backfilling soil 30. Therefore, it is not necessary to treat the earth retaining wall 2 as a temporary object, and it can be left as it is. it can. Therefore, in this construction method, the removal work which removes the temporary earth retaining wall becomes unnecessary, which also contributes to shortening the construction period.

  Furthermore, the gravitational retaining wall-like earth structure 10 is excellent in sliding stability against the applied earth pressure and can stably support the weight of the concrete structure 20 and the backfill earth 30.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1A, 1B ... Pillar row ground improvement body, 2 ... Earth retaining wall (A part), 3 ... Support body (support of concrete structure, B part), 3a ... Top end face, 10 ... Earth structure, 20 ... Concrete Structure (gate culvert), 20a ... legs, 20b ... inner space, 30 ... backfilling soil, 40, 50 ... roadbed, 100 ... composite (composite of soil structure and concrete structure), G1 ... original ground , G2 ... support layer

Claims (6)

The first step of creating a gravitational retaining wall-like soil structure by creating a columnar ground improvement body by stirring and mixing the original ground and solidified material, and arranging the columnar ground improvement body side by side,
The concrete structure is installed on the B part of the earth structure using the B part of the earth structure as a support for the concrete structure while holding the earth part A as the earth retaining wall. The second step,
A method for constructing a composite of an earth structure and a concrete structure, comprising a third step of constructing a composite of the earth structure and the concrete structure by backfilling the concrete structure laterally and upward.   2. The earth structure and concrete structure according to claim 1, wherein in the first step, at least a lower end of the columnar ground improvement body constituting the part B of the earth structure reaches a support layer of the original ground. Construction method of the composite. The concrete structure is a portal culvert;
In the first step, the earth structures are respectively formed at positions corresponding to the bipods of the portal culvert,
The construction method for a composite structure of a soil structure and a concrete structure according to claim 1 or 2, wherein, in the second step, a bipod of the gate-type culvert is installed at the portion B of each of the soil structures. . A gravitational retaining wall-like soil structure provided with a plurality of columnar ground improvement bodies made of a solid ground and a solidified material, wherein part A of the soil structure is a retaining wall, and the soil structure B part of the earth structure that is the support of the concrete structure,
A concrete structure disposed on the portion B of the earth structure;
A composite of a soil structure and a concrete structure, comprising a side of the concrete structure and an upper backfill soil.   The composite of the earth structure and the concrete structure according to claim 4, wherein a lower end of the columnar ground improvement body constituting the part B of the earth structure reaches a support layer of the original ground. The concrete structure is a portal culvert;
5. The soil structure is disposed at a position corresponding to a bipod of the portal culvert, and the bipod of the portal culvert is disposed at the portion B of the soil structure. Or the composite of the earth structure and concrete structure of 5.

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