JP4219746B2 - Lightweight embankment structure and construction method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightweight embankment structure including at least a lightweight embankment layer formed by stacking resin foam blocks in multiple stages, and a heavy article such as a road layer installed on top of the light embankment layer, and a construction method thereof.
[0002]
[Prior art]
As one of embankment methods on soft ground or landslide land, for example, a lightweight embankment method is known in which resin foam blocks as light embankment materials are stacked in multiple stages to form a lightweight embankment layer, such as the EPS method. . This construction method is widely used in various civil engineering works because it exerts excellent effects in reducing the cost for ground improvement and shortening the construction period.
[0003]
FIG. 8 shows an example of a conventional light-weight embankment structure. A pillar 41 such as H steel is erected opposite to the sloped surface 40 of the natural ground, and resin foam is formed in multiple stages between the sloped surface 40 and the pillar 41. The body blocks 1 are stacked, and a heavy object such as a roadbed material 42 and asphalt pavement 43 is installed thereon (see Patent Document 1: Japanese Patent Laid-Open No. 11-1000084). A wall surface material 41 a is attached to the support column 41 in order to protect the side surface of the resin foam block 1. In such a lightweight embankment structure, a resin foam such as expanded polystyrene may be a viscoelastic material, and a heavy object such as a roadbed is placed on a lightweight embankment layer in which resin foam blocks are stacked in multiple stages. If placed, the lightweight embankment layer will sink slightly in a short number of days.
[0004]
The amount of subsidence in this short term is assumed to be about 0.5% of the stacking height, and operations such as roadbed installation are performed on the assumption that such subsidence occurs. Of the 0.5% settlement, about 0.2% is attributed to the elasticity of the resin foam, and about 0.3% is uneven or resin foam blocks caused by the fasteners used during stacking. It is said from experience that a gap between blocks caused by sand entering between them is crushed by a load from above.
[0005]
In order to cope with such subsidence, it is necessary to take measures such as disposing the resin foam block 1 and the concrete floor slab in an unrestrained state with respect to the column 41. Further, when the resin foam blocks 1 are stacked as shown in the figure, since the self-supporting property itself is sufficient, it is not always necessary to stand the column 41, but the wall material 41a is directly foamed with resin. When placed on the body block 1, the wall material is destroyed due to the deformation of the resin foam block 1 due to the sinking, and therefore it is absolutely necessary to stand up the column 41 as a wall material support.
[0006]
Several proposals have been made to minimize such settlement. FIG. 9 shows an example of this. Lightweight embankment in which resin foam blocks 1 are stacked as light weight embankment layers between right and left wall bodies 31 and 31 and a pavement 32 is installed as a heavy load thereon. In the structure, the resin foam block 1 at a necessary location (shown by hatching in the figure) is made high in density so as to suppress the settlement of the entire embankment layer by a heavy object such as a pavement 32 (Patent Document 2). : JP 2000-282470 A). Moreover, although not shown in figure, in patent document 3 (Unexamined-Japanese-Patent No. 3-87417), it is set as the composite structure which has arrange | positioned the material with comparatively high compression rigidity like concrete inside a lightweight embankment layer in pile shape, and lightweight embankment. It is described that the deformation amount of the entire layer is reduced.
[0007]
[Patent Document 1]
JP-A-11-1000084 [Patent Document 2]
JP 2000-282470 A [Patent Document 3]
Japanese Patent Laid-Open No. 3-87417
[Problems to be solved by the invention]
The method described in Patent Document 2 that attempts to suppress the sinking of the lightweight embankment layer using resin foam blocks having different densities is effective as a countermeasure against elastic deformation and creep deformation of the resin foam block. However, there is no effect of suppressing subsidence caused by unevenness caused by the binding tool used at the time of stacking or by a gap between blocks caused by sand entering between the resin foam blocks. For this reason, it is impossible to omit the conventional countermeasures against settlement as described above. Also, it is not easy to prepare a plurality of types of resin foam blocks having different densities at the construction site.
[0009]
The method of arranging a material with relatively high compression rigidity, such as concrete, in a pile shape to increase the overall weight, reduces the original advantages of a lightweight embankment structure and reduces the load of the concrete. Therefore, it is necessary to take special measures for the ground.
[0010]
The present invention has been made in view of the circumstances as described above. While using one type of resin foam block as a lightweight embankment material, various measures conventionally required for the initial settlement of the lightweight embankment layer are effective. It is an object of the present invention to provide a new lightweight embankment structure and a construction method thereof that can be omitted, thereby improving the construction cost and construction efficiency as a whole.
[0011]
[Means for Solving the Problems]
A lightweight embankment structure according to the present invention is a lightweight embankment structure including at least a lightweight embankment layer formed by stacking resin foam blocks in multiple stages and a heavy article such as a road layer installed on top of the lightweight embankment layer. The lightweight embankment layer is in a state of being subjected to a predetermined compression by an appropriate means, and a heavy object such as the road layer is disposed thereon.
[0012]
In addition, the construction method of the lightweight embankment structure according to the present invention is a construction of a lightweight embankment structure formed by installing a heavy load such as a road layer on the lightweight embankment layer formed by stacking and molding resin foam blocks in multiple stages. In this method, after the lightweight embankment layer is formed, a predetermined compression is applied to the lightweight embankment layer by an appropriate means, and a heavy object such as a road layer is placed on top of the lightweight embankment layer while maintaining the state. It is characterized by performing the installation work.
[0013]
In the light weight embankment structure and the construction method according to the present invention, before installing a heavy load such as a road layer on the light weight embankment layer, the light weight embankment layer sinks in a short number of days due to the load from above by the weight portion. Since the lightweight embankment layer will be pre-compressed by appropriate means as much as possible, even if a heavy object such as a road layer is installed on the lightweight embankment layer in the subsequent work, further subsidence will be substantially eliminated. Does not occur. Therefore, when the support is built, the work for bringing the resin foam block and the support into an unconstrained state as in the conventional case can be omitted. Moreover, it becomes possible to arrange | position a wall surface material directly to the side surface of a resin foam, and even if a support | pillar itself is abbreviate | omitted, special support will not arise. Therefore, the construction cost and construction efficiency are greatly improved.
[0014]
In addition, the extent which compresses a lightweight embankment layer beforehand is about 0.3 to 0.5% of the height of a lightweight embankment layer, and about 1.2% at maximum. The gap that is easily formed between the resin foam blocks is not crushed by the compression performed in advance, and the elastic deformation of the resin foam also proceeds.
[0015]
Although the construction method of the lightweight embankment structure by this invention can be implemented in various different aspects, it is effective to carry out by the following processes. That is, a step of starting a load bearing material such as a steel rod having one end fixed to the basic concrete with an anchor plate or the like, and stacking resin foam blocks in multiple stages while passing the load bearing material to form a lightweight embankment layer, The step of forming the concrete slab on the lightweight embankment layer so that the tip of the load bearing material protrudes, using the tip of the load bearing material protruding from the formed concrete floor slab (for example, cutting the screw at the tip, A step of applying a predetermined vertical compression to the light-weight embankment layer, and a step of installing a heavy object such as a road layer on the concrete slab.
[0016]
In addition, in order to compress the light weight embankment layer in advance, it is also possible to use a means for placing the loaded load in accordance with a predetermined compression amount, sinking it, fixing it in that state, and then removing the loaded load.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on embodiments. 1 to 4 illustrate an example of a method for constructing a lightweight embankment structure according to the present invention, step by step. First, foundation maintenance is performed according to a regular method, and foundation concrete 10 is placed in an area where the lowermost resin foam block 1a (see FIG. 2) is to be placed. Prior to placing, an anchor plate 21 is installed at a predetermined position, and a steel rod 20 as a strength material having one end fixed to the anchor plate 21 by appropriate means such as welding or screwing is set up in a vertical posture (see FIG. (See also 5). The rising height of the steel bar 20 needs at least a length that protrudes from the upper surface when the lowermost resin foam block 1a is placed on the foundation concrete 10 (FIG. 2, FIG. 2). 6). A screw 22 is cut at the tip of the steel rod 20.
[0018]
After starting up the required number of steel bars 20, the required bar arrangement is performed, concrete is placed and the hardening is awaited. If necessary, the weir 11 for positioning the lowermost resin foam block 1a to be arranged is also formed at the edge of the valley of the foundation concrete 10 at the same time. The arrangement density of the steel bars 20 may be set as appropriate according to the density and height of the resin foam block 1 used in the light-weight embankment structure to be constructed. About one per square meter is sufficient.
[0019]
The lowermost resin foam block 1a is spread on the constructed basic concrete 10. As the resin foam block 1, it is desirable to use the resin foam block 1 in which the longitudinal groove 2 through which the steel rod 20 can pass is formed on the peripheral side wall as shown in FIG. It is easy to arrange the adjacent resin foam blocks 1 so as to accommodate the steel rods 20 in the longitudinal grooves 2, and as a result, as shown in FIG. Can be easily arranged in a state where the side walls are in close contact with each other and with the tip of the steel rod 20 protruding from the surface through the longitudinal groove 2. Instead of the longitudinal groove 2 or in addition to the longitudinal groove 2, a through hole 3 through which the steel rod 20 can pass may be formed. Thereby, the freedom degree of the starting position of the steel bar 20 and the arrangement position of the resin foam block 1 becomes large, and the work efficiency can be improved.
[0020]
As shown in FIG. 2 and FIG. 6, after laying down the lowermost (first stage) resin foam block 1 a, a coupling nut 23 is attached to the tip of each protruding steel bar 20. A steel rod 20 a having a screw 22 a at the lower end is screwed into the coupling nut 23. In this state, the second-stage resin foam block 1 is spread in the same manner as in the lowermost resin foam block 1a. When the length of the steel rod 20a is the same as the thickness of one resin foam block, the tip of the steel rod 20a protrudes from the surface of the resin foam block. The coupling nut 23 is attached in the same manner as in, and the next steel rod 20a is attached thereto. In that state, the third-stage resin foam block 1 is spread in the same manner. Thereafter, the same operation is repeated up to the uppermost resin foam block 1. Note that the resin block 1a may be laid out in a grid pattern as shown or a zigzag pattern.
[0021]
When the length of the steel rod 20a is a length corresponding to a plurality of the resin foam blocks 1, the joining operation using the coupling nut 23 is performed after the resin foam blocks 1 are stacked over a plurality of stages. . In the case where the length of the steel bar 20a reaches the surface of the uppermost resin foam block 1, no intermediate joining work is required. In consideration of workability, a connecting steel rod having an appropriate length may be used. The length of the steel rod 20 fixed to the anchor plate 21 may be a length that reaches the plurality of stages of resin foam blocks, and is a length that protrudes from the surface of the uppermost resin foam block. May be.
[0022]
Next, as shown in FIG. 3, a concrete floor slab 5 is constructed on the uppermost resin foam block group in the same manner as in the conventional construction method. At that time, when the tip of the steel rod 20a (20) protruding from the uppermost resin foam block surface has a length protruding from the upper surface of the concrete floor slab 5 to be constructed, If it does not have the length, the necessary joining work is performed in the same manner using the coupling nut 23. As shown in FIG. 7, an appropriate cylindrical body 24 such as a vinyl chloride pipe is covered with a portion that comes into contact with concrete for the concrete floor slab placed by the steel rod 20 a so that the concrete does not adhere to the steel rod 20 a. . After that, the necessary reinforcements are placed and concrete is placed, and the concrete is awaited to harden.
[0023]
After the concrete is hardened, a steel plate 25 functioning as a pressure equalizing plate similar to the anchor plate 21 is attached to each steel rod 20a via a cushion plate (not shown) if necessary. A nut 26 is attached to each steel rod 20a from above, and the nut 26 is tightened. If necessary, a lock nut 27 is attached. Thereby, the resin foam block group (lightweight embankment layer) stacked in multiple stages is in a state where a load is applied via the concrete floor slab 5, and the gap that tends to occur at the stratified interface of the stacked resin foam blocks is It is no longer crushed, and the elastic deformation of the resin foam also proceeds to compress the whole. The lower end of the steel bar 20 is fixed to the foundation concrete 10, and the compression of the resin foam block group appears as the settlement of the lightweight embankment layer.
[0024]
The amount of subsidence (compression amount) is proportional to the amount of tightening of the nut 26 and can be adjusted as appropriate. It is predicted that the amount of subsidence is caused by the load of heavy objects such as road layers built on the concrete floor slab 5 at each construction site. At least tighten until a settlement corresponding to the initial settlement of the lightweight embankment layer is obtained. Although it differs depending on the design environment, it is usually in the range of about 0.3 to 0.5%, at most about 1.2% of the stacking height. It should be noted that the tightening degree by the nut 26 is desirably equal in all the steel bars 20a (20), but there may be some variation. Moreover, you may make it tighten a road shoulder side rather than a natural mountain slope side. The steel plate 25 is attached to each steel bar 20a in order to disperse the tightening force by the nut 26 and prevent the concrete floor slab 5 from being broken. May be used. A common steel plate may be used for a plurality of steel bars.
[0025]
After performing the required tightening, by installing heavy objects such as the roadbed material 42 and the asphalt pavement 43 on the concrete floor slab 5 according to a regular method, the lightweight embankment structure according to the present invention shown in FIG. 4 is completed. As described above, the initial settlement of the light-weight embankment layer due to heavy objects such as a road layer, which naturally occurs in a normal construction method, has already occurred, and the resin foam block 1 stacked after the installation of the road layer or the like has occurred. There is no significant change in the side of (1a). Therefore, it becomes possible to easily attach or spray the wall surface material 41a to the side surface of the resin foam block 1, and as in the conventional method shown in FIG. No need to build. Although not shown in the figure, even when attaching wall materials, simple struts may be attached to the basic concrete, and wall materials such as lightweight mortar boards may be fixed thereto, and a lath net is attached to the side of the resin foam block Mortar can be sprayed to make the wall material. Therefore, the construction cost and construction efficiency of the lightweight embankment structure are greatly improved.
[0026]
In the above, as a means for pre-compressing the stacked resin foam block group, it is screwed into a steel rod fixed at one end to the foundation concrete and a screw cut at the tip of the steel rod (or a steel rod connected to the steel rod). Although the means comprising the tightening force by the nut is shown, a wire or fiber reinforced resin having screw rods at the lower and upper ends can be used instead of the steel rod. In addition, it may be a pre-compression means for loading the loaded luggage in advance. Further, it is desirable to apply such pre-compression (pre-settlement) to the entire area of the lightweight embankment layer, but it may be performed only on the vicinity of the side surface of the resin foam block group to which the wall material is attached. Good. In that case, the intended purpose can be almost achieved if it is performed on an area of about 1.0 to 2.0 m from the side surface to the natural ground side.
[0027]
Further, when a plurality of steel rods are connected to have a predetermined length, the steel rods are coupled using a coupling means that restricts upward movement but allows downward movement. You may do it. Thereby, even if creep deformation over a long period occurs in the resin foam block, the steel rod can appropriately cope with the settlement.
[0028]
【The invention's effect】
As described above, in the lightweight embankment structure and its construction method according to the present invention, before installing a heavy load such as a road layer on top of the lightweight embankment layer, the lightweight embankment layer is shortened by the load from above the weight part. Since the lightweight embankment layer is pre-compressed by the amount that will sink in days, even if a heavy object such as a road layer is installed on the lightweight embankment layer in the subsequent work, no further settlement occurs. Therefore, it is possible to omit various means for the initial settlement of the lightweight embankment layer, which has been necessary conventionally, and the construction cost and construction efficiency are greatly improved.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram for explaining an example of a method for constructing a lightweight embankment structure according to the present invention in a step-by-step manner and showing a state in which an anchor plate is raised on foundation concrete.
FIG. 2 is a view showing a state in which the lowermost resin foam block is spread.
FIG. 3 is a diagram showing a state in which a concrete slab is constructed on a lightweight embankment layer and the lightweight embankment layer is pre-compressed.
FIG. 4 is a sectional view showing a lightweight embankment structure according to the present invention.
FIG. 5 is a diagram illustrating a steel rod and a coupling nut.
FIG. 6 is a diagram for explaining a state in which a steel foam block is spread through a steel rod.
FIG. 7 is a view for explaining a mode in which a resin foam block is pre-compressed by tightening a nut from above a concrete floor slab.
FIG. 8 is a view showing an example of a conventional lightweight banking structure.
FIG. 9 is a view showing another example of a conventional lightweight banking structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a ... Resin foam block, 2 ... Longitudinal groove formed in resin foam block, 5 ... Concrete floor slab, 10 ... Foundation concrete, 20, 20a ... Steel rod (strength material), 21 ... Anchor plate, 23 ... Coupling nut, 24 ... cylinders such as PVC pipe, 25 ... Steel plate (equal pressure plate), 26 ... Nut

Claims (3)

A lightweight fill layer resin foam block was molded stacking in multiple stages, a lightweight embankment structure at least comprises a a heavy, such as road and placed on top of the lightweight embankment layer layer, lightweight embankment layer on foundation concrete The resin foam blocks are stacked in multiple stages while the load resistant material having one end fixed is accommodated in and passed through a vertical groove formed on the side wall around the resin foam block, and the lightweight embankment layer is formed of the load resistant material. A lightweight embankment structure characterized by being subjected to a predetermined vertical compression using a tip, and a heavy object such as the road layer is installed thereon. The resin foam block A construction method of a lightweight embankment structure formed by installing a weight of such upper portion road layer lightweight embankment layer molded stacked in multiple stages, lightweight fill layer at one end to the foundation concrete The resin foam blocks are stacked in multiple stages while the fixed load-bearing material is accommodated in and passed through the vertical grooves formed on the side walls around the resin foam block . After the lightweight embankment layer is formed , Using the tip, the lightweight embankment is subjected to a predetermined vertical compression, and while maintaining this state, a heavy load such as a road layer is installed on top of the lightweight embankment. Construction method of lightweight embankment structure. It is a construction method of a lightweight embankment structure formed by installing heavy objects such as road layers on top of a lightweight embankment layer formed by stacking resin foam blocks in multiple stages,
A process of forming a lightweight embankment layer by stacking resin foam blocks in multiple stages while allowing the load-bearing material fixed at one end to the foundation concrete to be accommodated in a longitudinal groove formed on a side wall around the resin foam block and passing through the groove .
Forming a concrete slab on a lightweight embankment layer so that the tip of the load bearing material pops out;
A step of applying a predetermined vertical compression to the lightweight embankment using the tip of the load bearing material, and a step of installing a heavy object such as a road layer on the concrete slab,
The construction method of the lightweight banking structure characterized by having at least.

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