JP2023114198A - Construction method for banking - Google Patents

Abstract

To provide a construction method for banking which enables simple and quick construction using fluidized soil, and has durability against external factors such as stagnation of rainwater and dryness.SOLUTION: In a construction method for banking, a bag body 2a is arranged on the outer periphery of a banking construction place, the inside of the bag body 2a is filled with a filer to form a bag body form 2, the bag body form 2 is built up to a first-stage height, then first-stage fluidized soil 3 is installed up to a top end height of the bag body form 2, the first-stage fluidized soil 3 is cured to a predetermined uniaxial compressive strength, then the bag body form 2 is installed on the first-stage fluidized soil 3 similarly to the first stage, the bag body form 2 is built up to a second-stage height and the second-stage fluidized soil 3 is installed, the above operation is repeatedly performed and the fluidized soil 3 is installed up to a predetermined height, and then the upper end of the top layer of the fluidized soil 3 is covered with a protective layer 4 having a drainage and water retention and load dispersion effect.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to an embankment construction method for use in railways and the like, and more particularly to an embankment construction method using fluidized soil.

For example, due to the nature of embankment for railways, it is often required to work in places with poor workability such as narrow spaces, and to work in limited hours such as at night. is required. Moreover, in recent years, due to the increase in damage caused by torrential rains and the like, there is an increasing demand for early restoration of collapsed embankments.

Fluidized soil, which is made by mixing solidifying materials such as water and cement with soil generated from construction, has high fluidity and filling properties. Compared to the case where it is done, it is possible to save labor and speed up embankment construction.

When constructing an embankment using the fluidized soil, it is necessary to provide a formwork on the side to prevent outflow during the placement of the fluidized soil. Conventionally, large sandbags and PC retaining walls have been used as formwork. However, large sandbags are only temporary materials and cannot be used as permanent structures. Therefore, when large sandbags are used, it is necessary to remove the large sandbags after the fluidized soil has hardened and construct a slope. On the other hand, PC retaining walls are limited in size due to transportation and manufacturing, and it takes a long time to manufacture a large PC retaining wall. Therefore, in these methods, it is not possible to make full use of the advantages of labor saving and speeding up construction when the fluidized soil is used as the embankment material.

As an embankment construction method using fluidized soil, for example, Patent Document 1 discloses an embankment construction method in which fluidized soil is poured into a dam in which a plurality of boxes or bags are filled with a filler. It is

Japanese Patent Application Laid-Open No. 2002-21083

However, fluidized soil has the property of deteriorating due to external factors such as stagnant water such as rainwater and drying due to outside air. For example, in order to ensure the long-term performance of railroad embankments to support the train load, it is necessary to protect them from these external factors and improve their durability.

The present invention has been made in view of the above circumstances, and embankments that can be constructed easily and quickly using fluidized soil and have durability against external factors such as stagnant rainwater and drying. The purpose is to provide a construction method for

In order to solve the above problems, the present invention provides a method for constructing an embankment using fluidized treated soil, in which a bag is arranged on the outer periphery of the embankment construction site, and a filler is filled inside the bag. After forming a bag form and stacking the bag form to the height of the first stage, the first level of fluidized soil is cast to the height of the top of the bag form, and the first level of fluidization is performed. After the treated soil has hardened to a predetermined uniaxial compressive strength, a bag form is placed on the first stage fluidized soil in the same manner as the first stage, and the bag form is placed on the second stage. The second layer of fluidized soil is piled up to the height of , and this is repeated until the fluidized soil is placed to a predetermined height, and then the top of the top layer of the fluidized soil is drained.・It is characterized by being covered with a protective layer that has water retention and load distribution effects.

The protective layer is composed of two types of layers with different water permeability, and it is preferable to provide a lower layer with high water permeability immediately above the fluidized soil and an upper layer with low water permeability thereon.

The fluidized soil may have a 28-day unconfined compressive strength of 600 kPa or more.

The unconfined compressive strength of the placed fluidized soil when hardening is obtained by measuring the ground reaction force coefficient of the fluidized soil in a small FWD test, and obtaining the deformation coefficient from the relationship between the ground reaction force coefficient and the deformation coefficient. , the uniaxial compressive strength of the fluidized soil may be obtained from the relationship between the deformation coefficient and the uniaxial compressive strength.

A rod-shaped reinforcing member may be provided, one end of which is fixed to the bag formwork and the other end of which is fixed in the fluidized soil.

The bag may be made of synthetic fibers.

The filler may be concrete.

After the first-stage fluidized soil has hardened to a predetermined uniaxial compressive strength, the first-stage bag mold is dismantled, and the bag of the dismantled bag-body mold is subjected to the first-stage fluidization treatment. Place it on top of the soil, fill the inside of the bag with a filler to form a bag form, place the second stage of fluidized soil, and repeat this until the fluidized soil reaches a predetermined height. Soil may be placed.

A retaining wall may be provided on the slope of the embankment. Moreover, the embankment may be a railway embankment.

According to the present invention, using fluidized soil, embankment that has durability against external factors such as stagnant rainwater and drying and can be used for railroads and the like can be constructed simply and quickly. can be done.

1 is a perspective view showing an example of a bag form used in the present invention; FIG. It is a sectional view explaining an example of a construction procedure of embankment concerning an embodiment of the present invention. Ground reaction force coefficient K _{P. 10} is a graph showing the relationship between _FWD value and deformation coefficient E50. Fig. 3 is a graph showing the relationship between the unconfined compressive strength q _u and the modulus of deformation _E50 ; It is sectional drawing which shows the construction example of the embankment for railways. FIG. 4 is a perspective view showing an example of a reinforcement method when constructing a steep slope embankment. It is a sectional view showing an example of construction of embankment with a steep slope. FIG. 3 is a perspective view showing an example of a fixing reinforcing bar having a fixing portion at its tip; FIG. 4 is a perspective view showing an example in which long fixing members are attached to the ends of a plurality of fixing reinforcing bars; It is sectional drawing explaining the example of the construction procedure of the embankment concerning different embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

FIG. 1 shows an example of a bag form 2 used in the present invention. The bag formwork 2 is formed by arranging the bag 2a on the outer circumference of the site where the embankment is to be constructed, and then filling the interior of the bag 2a with a filler such as concrete through the inlet 2b. The bag formwork 2 can be used as the main structure of the embankment as it is after construction of the embankment, and the bag body 2a is preferably made of, for example, synthetic fibers that are excellent in weather resistance and strength. In addition, it is preferable that the bag body 2a before being filled with the filler has a weight that can be folded, for example, and transported and installed manually.

An example of the procedure of the embankment construction method according to the embodiment of the present invention will be described below with reference to FIG. This embodiment is a construction method for embankment for railways.

First, for example, a synthetic fiber bag 2a is placed at a predetermined position on site, filled with a filler such as concrete, and shaped into the shape shown in FIG. The filling material is press-fitted by, for example, a pump truck or the like. The bag mold 2 filled with the filler has a height of, for example, about 500 mm. The width is a dimension that can resist the lateral pressure during the placement of the fluidized soil, for example, about 1,000 to 4,000 mm. . The longitudinal dimension of the bag formwork 2 is not particularly limited, but it may have a long shape arranged along the longitudinal direction of the embankment, for example, about 50 m.

Next, another bag 2a is placed on top of the bag form 2 filled with the filler, and the bag form 2 is formed by similarly filling the bag with the filler. Then, for example, when the two bag molds 2 are superimposed, curing is performed until the filler hardens. When concrete with a nominal strength of 24 N/mm ² is used as the filler, curing for about one day is recommended. Similarly, as shown in FIG. 2(a), the bag formwork 2 is piled up on both ends of the embankment to a height of, for example, about 2 m. In the embodiment of FIG. 2( a ), four tiers of 500 mm high bag forms are stacked.

After that, the fluidized soil 3 is placed between the bag forms 2 stacked up to a predetermined height as the first stage, up to the top height of the bag forms 2 (Fig. 2(b)). As the fluidized soil 3, general soil obtained by mixing solidifying material such as water and cement with soil generated from construction may be used. Conventionally, when using fluidized soil as an embankment material for railways, there are no clear regulations regarding the design standard strength of fluidized soil. A pressure of about 000 kPa was used. However, in recent years, experimental research by the present inventors has shown that if the unconfined compressive strength _qu of the fluidized soil is increased to about 600 kPa or more by providing a protective layer on the embankment of the fluidized soil, the repeated train load will increase. It has been confirmed that the structure can withstand the action. In this embodiment, the fluidized soil 3 having a composition of 1,200 kPa with a strength of 28 days is used.

The placed fluidized treated soil 3 is hardened until it reaches a uniaxial compressive strength determined according to the weight of the bag form 2 and the like. In this embodiment, the material is cured until the unconfined compressive strength reaches approximately 50 kPa. For example, when the 28-day strength is 1,200 kPa, the strength is usually 50 kPa or more at about 1 day of age.

Uniaxial compression testing requires a dedicated testing machine, takes time, and the number of test specimens for uniaxial compression testing is limited, making it difficult to conduct tests that reflect on-site conditions. There's a problem. Therefore, in this embodiment, a small FWD test is used as a method for easily confirming the strength of the fluidized treated soil 3 after placement on site. First, the ground reaction force coefficient _KP . _{The FWD} value is measured, and the ground reaction force coefficient K _P. From the relationship between _{the FWD} value and the deformation coefficient _E50 , the deformation coefficient _E50 is obtained as shown in FIG. _Furthermore , the unconfined compressive strength _qu is obtained as shown in _FIG . The strength of the fluidized soil 3 can be grasped from the uniaxial compressive strength _qu thus obtained.

When it is confirmed that the fluidized treated soil 3 has hardened to a predetermined strength, as the second stage, the bag formwork 2 is piled up at a position where a predetermined inclination can be obtained in the same manner as described above ( Fig. 2(c)), furthermore, the fluidized treated soil 3 with a 28-day strength of 1,200 kPa is placed up to the height of the top of the bag formwork 2 (Fig. 2(d)). In this embodiment, the height of one stage of the fluidized treated soil 3 that is placed at one time is set to 2 m, and as shown in FIGS. And the placement of the fluidized treated soil 3 is repeated. In addition, when placing the uppermost fluidized soil 3, a specimen for the uniaxial compression test to be tested after embankment construction is taken.

As shown in FIG. 2( f ), after the placement of the third layer of fluidized soil 3 is completed, heavy machinery work is carried out to lay railroad tracks and the like on top of the fluidized soil 3 . In this embodiment, when performing this heavy machinery work, the unconfined compressive strength _qu of the fluidized soil 3 is 100 kPa or more as a strength that allows general spreading and rolling machines to work on the fluidized soil 3. and In the case of the fluidized soil 3 having a 28-day strength of 1,200 kPa, the uniaxial compressive strength _qu is usually 100 kPa or more after curing for about 2 days.

If the unconfined compressive strength _qu of the uppermost fluidized soil 3 that has been cured for about 2 days has not reached 100 kPa, it is cured for about another day, and then the small FWD test is performed again to test the fluidized soil 3. Check the unconfined compressive strength q _u . This is repeated until a predetermined intensity expression can be confirmed.

When it is confirmed that the unconfined compressive strength _qu is 100 kPa or more, the upper surface of the fluidized soil 3 of the uppermost layer is covered with water to prevent rainwater from accumulating, to protect against drying, and to disperse the train load, etc. , a protective layer 4 is applied. In this embodiment, as shown in FIG. For example, a coarse gravel layer is used, and the upper layer 6 is a fine-grained sand layer. By reducing the water permeability of the upper layer 6 in this way, drainage is promoted at the upper layer 6 and the boundary between the upper layer 6 and the lower layer 5, and rainwater is less likely to soak into the fluidized soil 3 through the lower layer 5. . The thickness of the entire protective layer 4 is, for example, approximately 300 mm. The protective layer 4 can also prevent excessive drying of the fluidized soil 3 and can have an effect of dispersing the load of a train or the like. The protective layer 4 is provided in a range covering at least the upper surface of the fluidized treated soil 3, and may cover the upper surface of the bag mold 2 as shown in FIG. 5(a). In this way, an embankment 10 is formed in which the upper surface of the fluidized treated soil 3 is protected by the protective layer 4 and the side surface is protected by the bag formwork 2 .

Furthermore, when used as a railway embankment, as shown in FIG. Then, a uniaxial compression test is performed on the specimen for the uniaxial compression test taken when placing the uppermost fluidized soil 3, and the uniaxial compression strength _qu of the fluidized soil 3 is a predetermined strength, that is, In this embodiment, it is confirmed that the pressure is 1,200 kPa or more. After confirming the unconfined compressive strength _qu , run a test train, etc., to confirm that the support performance for running the train has been secured, and then start running the train.

As described above, according to the present embodiment, the bags 2a that can be transported and installed manually are arranged along the range of the embankment 10, and the filling material is press-fitted into the bags 2a by a pump truck or the like. , the bag formwork 2 can be easily installed. Furthermore, since the installed bag body formwork 2 can be used as it is as the main body structure, removal of the formwork and slope work can be omitted. Therefore, the construction period can be shortened and the embankment can be constructed quickly. In addition, if concrete is used as the filling material for the bag formwork 2, a weed control effect on the slope can be expected.

In addition, by constructing a protective layer 4 on the upper surface of the fluidized soil 3, the fluidized soil 3 is protected from external factors such as stagnant rainwater and drying due to the outside air, and the durability of the fluidized soil 3 In addition to improving the load distribution of the train, the effect of dispersing the train load can also be expected. Therefore, conventionally, for example, in the tunnel invert section, fluidized soil with a 28-day strength _qu28 of about 6,000 kPa was used, but a lower strength fluidized soil ( _qu28 = 600 kPa or more, for example, 1200 kPa) was used. It becomes applicable and improves versatility. The side surface of the fluidized treated soil 3 can be protected from external factors by leaving the continuous bag formwork 2 thereon.

Furthermore, by confirming the strength of the fluidized soil 3 by the small FWD test, it is possible to evaluate the strength of the fluidized soil 3 at an easier and more appropriate timing than confirmation of the strength by the conventional uniaxial compression test. Become. Therefore, work on the fluidized soil 3 such as the protective layer 4 and the track 8 can be performed at appropriate timing, and the embankment 10 can be constructed quickly.

FIG. 6 shows a different embodiment of the present invention, showing the construction procedure of the bag formwork 2 when the slope is steep.

First, as in the example of FIG. 2, the bag body 2a is installed at a predetermined position on site, and a filling material such as concrete is filled from the injection port 2b of the bag body 2a to form the bag formwork 2 (FIG. 6(a)).

In this embodiment, the bag mold 2 and the fluidized soil 3 are integrated by attaching rod-shaped reinforcing members to the bag mold 2 to fix the fluidized soil 3 . As a result, collapse of the bag formwork 2 due to an earthquake or the like can be prevented, and the stability of the steep embankment 10 formed by the fluidized treated soil 3 can be improved. In this embodiment, a fixing reinforcing bar 22 is used as the rod-shaped member. First, as shown in FIG. 6(b), fixing reinforcing bars 21 are arranged vertically at suitable intervals in the longitudinal direction on the outer surface of the embankment of the bag formwork 2 . After that, a fixing reinforcing bar 22 fixed to the fixing reinforcing bar 21 and fixed to the fluidized soil 3 is arranged. One end of the fixing reinforcing bar 22 is bent, and the bent portion 22a is hooked to the fixing reinforcing bar 21, and the other end is arranged to extend horizontally (FIG. 6(c)). Then, the next bag body 2a is placed on the fixing reinforcing bar 22, and the filling material is filled to form the bag formwork 2 (FIG. 6(d)).

In this way, the fixing reinforcing bars 22 are sandwiched between the bag-body molds 2 and fixed in a state in which the fixing reinforcing bars 22 extend in the horizontal direction. Similarly, fixing reinforcing bars 22 are arranged on each stage of the bag formwork 2 (FIG. 6(e)). When the bag formwork 2 is piled up to a predetermined height of, for example, 2 m (Fig. 6(f)), the fluidized soil 3 is placed up to the height of the top of the bag formwork 2 in the same manner as in Fig. 2(b). . The diameter and number (installation intervals) of the anchoring reinforcing bars 22 and the anchoring length to the fluidized soil 3 are designed so that the embankment 10 can stably withstand earthquakes as a permanent structure. .

When the above steps are repeated and the desired embankment height is reached, as shown in FIG. The bag body formwork 2 is integrated. If the slope is relatively gentle, instead of the retaining wall 9, a sprayed material having weather resistance against ultraviolet rays, rainwater, etc., or a planar or mesh-like reinforcing material may be laid. In addition, in the case of the mesh-like reinforcing material, means for protecting the reinforcing bars 21 and 22 exposed on the surface is separately required.

Furthermore, after confirming the strength of the fluidized soil 3, a protective layer 4 is constructed on the fluidized soil 3 in the same manner as in the embodiment shown in FIG. 2(g).

Conventionally, when constructing a steep slope embankment using fluidized soil, it was necessary to construct a strong wall surface such as a PC retaining wall. There was a problem that there is In addition, when using large sandbags for embankment construction on a steep slope, it was necessary to take measures to ensure stability during construction corresponding to the steep slope. On the other hand, according to the embodiment shown in FIG. 6, for the embankment having a steep slope, a rod-shaped reinforcing material is arranged between the bag-body forms 2 and the fluidized treated soil 3 is placed to place the embankment. 10 can increase the stability of the structure. Furthermore, the stability of the embankment 10 is improved by integrating a plurality of bag forms 2 by constructing a retaining wall 9 or laying a planar reinforcing material or the like on the slope surface layer. The embankment 10 reinforced in this way can be applied when a sufficient area cannot be secured, such as when the land area is limited or when restoring an existing embankment with a steep slope.

In order to strengthen the fixation of the fixing reinforcing bar 22 and the fluidized treated soil 3, a rectangular or circular plate-like fixing portion 22b as illustrated in FIG. 8 is provided at the tip of the fixing reinforcing bar 22. good too. Alternatively, the tips of the plurality of fixing reinforcing bars 22 may be attached to a long fixing member 23, such as an L-shaped angle as shown in FIG.

Moreover, FIG. 10 shows the procedure of the construction method of the embankment 10 concerning still another embodiment of this invention.

The bag body 2a is installed at a predetermined position on site and filled with a filler to form the bag formwork 2 (FIG. 10(a)). In this embodiment, water is used as the filler. The bag mold 2 filled with the filler has a height and a width of about 1,500 mm, for example.

After that, the fluidized soil 3 is placed between the bag forms 2 to a height equal to or lower than the height of the top of the bag form 2, for example, to a height of 1,000 mm (Fig. 10(b)). The fluidized soil 3 may be the same as in the above-described embodiment.

After placing the fluidized treated soil 3 and curing it for about one day until it reaches a predetermined strength, the water is drained from the bag form 2 on the first stage, and the bag form 2 is dismantled (Fig. 10(c) ). Then, the bag body 2a of the dismantled bag body form 2 is placed on the fluidized treated soil 3 of the first stage, and the filling material is filled to form the bag body form 2 (Fig. 10(d)). . After that, the fluidized treated soil 3 is placed in the same manner as in the first stage (Fig. 10(e)), and after curing for about one day, the water is drained from the bag form 2, and the bag form 2 is dismantled (Fig. 10(f)).

The same process is repeated to pile up the fluidized soil 3 to a predetermined height (Fig. 10(g)). When it is confirmed that the uniaxial compressive strength _qu of the fluidized soil 3 satisfies a predetermined strength, two types of layers 5 and 6 with different water permeability are formed on the top surface of the fluidized soil 3, which is the uppermost layer. Then, a protective layer 4 is applied. Further, a retaining wall 9 is constructed from concrete or the like on the side surface of the fluidized soil 3 to integrate the stacked fluidized soil 3 in multiple stages. When used as a railway embankment, a crushed roadbed 7 and a track 8 are constructed on the upper surface of the protective layer 4 (FIG. 10(h)).

In this embodiment, water is used as the filling material for the bag formwork 2, and the same bag formwork 2 is repeatedly used in each stage, so embankment can be constructed at low cost.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive various modifications or modifications within the scope of the technical idea described in the claims, and these are also within the technical scope of the present invention. be understood to belong to

INDUSTRIAL APPLICABILITY The present invention is useful as an embankment construction method for use in railways and the like.

2 Bag Formwork 3 Fluidized Soil 4 Protective Layer 9 Retaining Wall 10 Embankment 21 Fixing Reinforcement 22 Fixing Reinforcement

Claims (10)

An embankment construction method using fluidized soil,
placing a bag on the outer periphery of the embankment construction site, filling the inside of the bag with a filler to form a bag form,
After stacking the bag formwork to the height of the first stage, pour the fluidized soil of the first stage up to the height of the crown of the bag formwork,
After the first-stage fluidized soil has hardened to a predetermined uniaxial compressive strength,
On top of the fluidized soil of the first stage, a bag formwork is installed in the same manner as the first stage, and the bag formwork is piled up to the height of the second stage to form the fluidized soil of the second stage. cast,
After repeating this and placing the fluidized soil up to a predetermined height,
A method of constructing an embankment, characterized in that the upper end of the uppermost layer of the fluidized soil is covered with a protective layer having drainage, water retention and load distribution effects. Claim 1, wherein the protective layer is composed of two types of layers with different water permeability, and a lower layer with high water permeability is provided immediately above the fluidized soil, and an upper layer with low water permeability is provided thereon. The embankment construction method described in . 3. The embankment construction method according to claim 1, wherein the fluidized soil has a 28-day unconfined compressive strength of 600 kPa or more. The unconfined compressive strength at the time of hardening of the poured fluidized soil is
Measuring the ground reaction force coefficient of the fluidized soil in a small FWD test,
Obtain the deformation coefficient from the relationship between the ground reaction force coefficient and the deformation coefficient,
The embankment construction method according to any one of claims 1 to 3, wherein the uniaxial compressive strength of the fluidized soil is obtained from the relationship between the deformation coefficient and the uniaxial compressive strength. The embankment construction method according to any one of claims 1 to 4, characterized by providing a rod-shaped reinforcing member whose one end is fixed to the bag formwork and whose other end is fixed in the fluidized soil. . The embankment construction method according to any one of claims 1 to 5, wherein the bag is made of synthetic fiber. The embankment construction method according to any one of claims 1 to 6, wherein the filler is concrete. After the first-stage fluidized soil has hardened to a predetermined uniaxial compressive strength,
The bag body form of the first stage is dismantled, the bag of the dismantled bag form is placed on the fluidized soil of the first stage, and the inside of the bag is filled with a filler to form a bag. A frame is formed and the second layer of fluidized soil is placed,
The embankment construction method according to any one of claims 1 to 4, characterized in that this process is repeated to place the fluidized soil up to a predetermined height. The embankment construction method according to any one of claims 1 to 8, characterized in that a retaining wall is provided on the slope of the embankment. The embankment construction method according to any one of claims 1 to 9, wherein the embankment is a railway embankment.

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