JP6782925B2 - Coastal / riverbank conservation method - Google Patents

Description

The present invention relates to a technique for filling a bag with sand or the like to prevent erosion on a coast or riverbank for conservation, preserving landscape / topography, and preventing flood damage.

When sand and earth and sand on the coast and riverbanks are eroded by waves and water currents, erosion of the beach, receding of the coastline, and destruction of aesthetics and landscape become problems. And as the erosion progresses, it becomes easy to cause flood damage and the like. Therefore, the conservation of coasts and riverbanks has become an important issue.
In the prior art, sandbags are filled with soil to create sandbags, and sandbags are piled up to build structures to prevent coastal and riverbank erosion or flood damage (for example, erosion prevention embankments) to prevent inundation. It is common. The technique of filling a long cloth bag with local sand to maintain the beach and sandy beach over a long distance is widely practiced especially overseas.
However, in places with rough waves or on coasts and river banks where there is a lot of garbage, the bags are damaged and the filled soil or local sand flows out, and as a result, sandbags or structures built by stacking sand-filled bags are created. There is a problem that it collapses.
On the other hand, it has been proposed to use a bag having very high strength and durability to prevent the outflow of filled sand due to the breakage of the bag, but the bag (the strength and durability are very high). Since the manufacturing cost of a bag) is high, there is a problem that the cost of construction using such a bag increases.

As another conventional technique, a ground improvement method for precipitating calcium carbonate in voids in the ground by a biochemical reaction of microorganisms has been proposed (see Patent Document 1). However, this technique (Patent Document 1) is a technique relating to a ground improvement method, and is not intended to solve the problems in the coast / riverbank conservation method described above.
Further, a ground consolidation method has been proposed in which the ground is consolidated by the reaction of carbon dioxide gas and calcium or the reaction of an alkaline earth metal compound by the biochemical reaction of microorganisms (Patent Document 2). However, this technique (Patent Document 2) is also a technique related to the ground improvement method and does not cover the coast / riverbank conservation method.

Japanese Patent No. 4599611 Japanese Patent No. 4621634

The present invention has been proposed in view of the above-mentioned problems of the prior art, and is a coast / riverbank maintenance method using a bag filled with a filler, and even if the bag used is damaged, it is caused by waves or water currents. The purpose is to provide a coastal / riverbank conservation method that can maintain the effect of preventing sediment erosion and keep the manufacturing cost of bags low.

The coastal / riverbank conservation method of the present invention
Microorganisms (1: urea-degrading bacteria, etc.) having the property of solidifying sand (3: including soil in the present invention) and nutrient sources (eg, urea) necessary for the microorganisms (1) to solidify sand (3). ) Or the step of mixing the calcium source (2) into the sand (3),
A step of filling a bag (4) with sand (3) mixed with microorganisms and a nutrient source or a calcium source (2), and
Includes the process of stacking (laying, laying) bags (4) filled with sand (3) on the shore or river shore to construct a flood prevention structure (10: for example, an erosion prevention bank). ,
The bag (4) is a material through which the injection tube needle of the drug solution injection device (syringe-shaped member) penetrates, and is a flexible material.
After filling the bag (4) with sand (3), the sand (3) mixed with microorganisms and a nutrient source or a calcium source (2) does not solidify (moderately) (even after a predetermined time T has passed). In some cases, it is characterized by having a step of supplying the microorganism (1) and the nutrient source or the calcium source (2) into the bag (4) by a chemical injection device .

In the present invention, the step of collecting the microorganism (1) from the construction (planned) site and
It is preferable to include a step of culturing the collected microorganism (1) (in an amount required for construction) .
Or, preferably used the sand microorganism and nutrients or calcium source are mixed as soil cover (20). In this case, the soil covering (20) is put on a bag filled with the sand mixed with microorganisms and a nutrient source or a calcium source, laid, laid or piled up.
However, even when a bag filled with sand containing no microorganism and nutrient source or calcium source is laid, laid or piled up, the sand mixed with microorganism and nutrient source or calcium source is used as soil covering (20). Can be covered.
Not only the bags (4) may be stacked and covered with the soil cover (20), but the bags (4) may be placed so-called "flat" and covered with the soil cover (20).

In the present invention, the predetermined time (T), the type of bag (4) sand (3) which is filled in, the type and amount of sand (3) a microorganism are mixed (1), in the sand (3) It is preferably determined on a case-by-case basis depending on the type and amount of the mixed nutrient source or calcium source (2).

According to the present invention having the above-described configuration, a structure for preventing erosion of earth and sand (10: for example, an erosion prevention embankment) is constructed by a bag (4) filled with sand (3: including soil in the present invention). Then, due to the biochemical activity or metabolism of the nutrient source (2: urea) or calcium source (2) and the microorganism (1: urea-degrading bacterium) mixed in the filling in the bag (4), the bag (for example) The sand (3) in 4) is solidified.
Therefore, even if the bag (4) is damaged, the sand (3) solidified in the bag (4) does not flow out, and constitutes a structure for preventing erosion of earth and sand (10: for example, an erosion prevention bank). Can be maintained. Then, a structure for preventing erosion (10: for example, an erosion prevention embankment) is maintained for a long period of time after construction, for example, erosion due to waves and water currents on the coast or riverbank is prevented, and the coast or riverbank is preserved. It is possible to preserve the landscape and terrain and prevent flood damage.

According to the present invention, even if the solidified filling (solidified sand 3) of the bag (4) is disassembled or left to stand, the solidified filling is the sand (3) collected locally. Moreover, since it is solidified by the biochemical action of microorganisms, it does not affect the environment.
Further, even if the bag (4) is damaged, the sand (3) solidified in the bag (4) does not flow out, and a structure for preventing erosion of earth and sand (10: for example, an erosion prevention bank) can be maintained. It can be done, so there is no need to use bags made of high-strength but expensive materials.
Alternatively, even if the durability of the bag (4) itself is low, the structure for preventing erosion of earth and sand (10: for example, the embankment for preventing erosion) can be maintained for a long period of time.
Further, a bag made of a naturally decomposable material (4) and a bag made of a material that is decomposed by ultraviolet rays (4) can also be used.

According to the present invention, the solidification using the microorganism (1) reduces CO ₂ emissions and prevents groundwater from being contaminated. Further, the solidification rate can be adjusted by adjusting the amount of the microorganism (1) and / or the amount of the nutrient source or the calcium source (2) added.
And, unlike the case of solidification by cement or the like, the influence on the environment is very small, and there is little possibility of causing environmental destruction. In particular, when a bag made of a naturally decomposable material (4) or a bag made of a material that is decomposed by ultraviolet rays (4) is used, even if such a bag (4) is left unattended, it decomposes over time. Therefore, the adverse effect on the natural environment caused by the bag left unattended is prevented.
In addition, since the microorganism (1) derived from the construction site is used, there is no risk of disturbing the biological environment at the construction site.

In the present invention, if the microorganism (1) is collected from the construction (planned) site, even if the sand (3) filled in the bag (4) solidifies, the metabolism of the microorganism (1) existing at the construction site can be achieved. As a result, there is little risk that the solidified sand (3) will disturb the biological environment at the construction site.
In other words, from a biological point of view, according to the present invention, the environment at the construction site can be preserved.

It is explanatory drawing which shows the process of collecting the microorganisms present at the construction site in embodiment of this invention. It is explanatory drawing which shows the step of culturing the microorganism collected in the step shown in FIG. It is explanatory drawing which shows the process of mixing the cultivated microorganism and a nutrient source or a calcium source in the sand to be filled in a bag. It is explanatory drawing which shows the process of filling a bag with sand mixed with a microorganism and a nutrient source or a calcium source. It is explanatory drawing which shows the process of building the erosion prevention embankment by stacking the bag filled with sand on the coast or the riverbank in the process of FIG. It is explanatory drawing which shows one aspect which supplies a nutrient source or a calcium source and / or a microorganism in a bag after constructing an erosion prevention embankment. It is explanatory drawing which shows the embodiment which supplies the nutrient source or calcium source and / or the microorganism into a bag after constructing the erosion prevention embankment, and is different from FIG. It is a flowchart which shows the work procedure of the illustrated embodiment. It is explanatory drawing which shows the action effect in the illustrated embodiment, (A) shows the case where the bag is broken in the prior art, (B) shows the case where the bag is broken in the illustrated embodiment. It is explanatory drawing which shows the state which used the sand which mixed the microorganism and the nutrient source or the calcium source as a soil cover in the illustrated embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In FIGS. 1 to 8, each step shown in FIG. 8 is shown in FIGS. 1 to 7. Hereinafter, each step of FIG. 8 will be described with reference to FIGS. 1 to 7.
In the coast / riverbank maintenance method according to the embodiment of the present invention, first, in step S1 of FIG. 8, the place where the coast / riverbank maintenance method is constructed (construction site on the coast or riverbank), construction specifications (construction conditions), etc. Is set.

For example, the construction position, scale (height, width, depth) of the erosion prevention embankment 10 (structure), and the size of the bag 4 (bag filled with sand 3) required for constructing the erosion prevention embankment 10. Then, the total number and the like are set. Further, the required amount of sand 3, the type and amount of microorganism 1, the type and amount of nutrient source (or calcium source) 2, and other specifications are set.
As described above, in the present invention, the word "sand" is used to include "soil". Therefore, in the illustrated embodiment, sand 3 includes soil.
As for the microorganism 1, the microorganism inhabiting the construction site (beach, underwater, river) is investigated, and the microorganism 1 having the property of solidifying the sand 3 is selected.
Note that step S1 in FIG. 8 is not shown in FIGS. 1 to 7.

In step S2 of FIG. 8, as shown in FIG. 1, sand 3 at the construction site is collected by the collecting means 7, and necessary microorganisms are extracted and cultivated in the research facility R. The research facility R is provided with a microorganism separation device R1 for separating the microorganism 1 from the sand 3 and a microorganism culture device R2 for culturing the microorganism 1.
As will be described later, in the illustrated embodiment, the microorganism 1 having the property of solidifying the sand 3 and the nutrient source (or calcium source) 2 necessary for the microorganism to solidify the sand 3 are mixed with the sand 3. The sand 3 filled in the bag 4 is solidified by the biochemical activity or metabolism of the microorganism 1.

The mode of solidifying the sand 3 filled in the bag 4 using the microorganism 1 is the same as in the prior art, and for example, there are the following three types of modes.
In the first aspect, a urea-degrading bacterium is selected as the microorganism 1, and urea (CO (NH ₂ ) ₂ ) and calcium (Ca) are used as the nutrient source (or calcium source) 2. Then, by utilizing the hydrolyzing action of urea by the urea-degrading bacteria, calcium carbonate (CaCO ₃ ) is precipitated between the particles of the sand 3 (filled in the bag 4), and the sand particles are adhered and filled in the gaps. , A method of solidification.
The formulas (1) to (6) shown below represent a series of urea hydrolysis reactions by urea-degrading bacteria. Calcium carbonate is precipitated through the chemical reactions represented by the formulas (1) to (6).
CO (NH ₂ ) ₂ + H ₂ O → NH ₂ COOH + NH ₃ ... (1)
NH ₂ COOH + H ₂ O → NH ₃ + H ₂ CO ₃ ... (2)
_{NH 3 + H 2 O → NH} 4 + + OH - ··· (3)
^{_{H 2 CO 3 → H + +}} HCO 3 - ··· (4)
^{_{HCO 3 - → H + + CO}} 3 2- ··· (5)
Ca ²⁺ + CO ₃ ^2- → CaCO ₃ ... (6)
Calcium carbonate (CaCO ₃ ) is precipitated by the formula (6) after being prepared in a weakly alkaline environment where calcium carbonate is likely to be precipitated by the pH raising reaction of the formula (3).

In the second aspect, glucose (C ₆ H ₁₂ O ₆ ) is used as the nutrient source 2, the silica is gelled by the microorganism 1, and the network structure of the silica colloid is formed in the sand 3 (filled in the bag 4). It is a method of forming between particles and solidifying them.
The formulas (7) to (10) shown below show the chemical reaction until the network structure of the silica colloid is formed by the microbial metabolism of glucose (C ₆ H ₁₂ O _6, nutrient source).
_{C 6 H 12 O 6 + 6O} 2 → 6H 2 O + 6CO 2 ( aerobic conditions) (7)
C ₆ H ₁₂ O ₆ → 2CO ₂ + C ₂ H ₅ OH (under anaerobic conditions) ・ ・ ・ (8)
_{CO 2 + H 2 O → HCO} 3 - + H + ··· (9)
-Si-OH + HO-Si- → -Si-O-Si- + H ₂ O ... (10)
When CO ₂ generated by the microbial metabolism of glucose represented by the formulas (7) and (8) is dissolved in the silica colloidal solution, H ⁺ is generated as shown by the formula (9), so that the H ⁺ concentration increases and the solution The pH value inside drops. As a result, the potential of the particle surface of the silica colloid changes and condenses, the particles approach each other, and the siloxane bond (-Si-O), which is a dehydration reaction between the silanol groups (-Si-OH) on each particle surface, is formed. -Si-) is produced (formula (10)), and a network structure of silica colloid is formed.

The third aspect is a method in which a calcium phosphate compound (CPC) is used as the calcium source 2 and the microorganism 1 is used to solidify the sand 3 (filled in the bag 4).
The gel-like or amorphous calcium phosphate compound (CPC) has a property of changing the crystal form from gel-like to high-strength hydroxyapatite with the passage of time. Utilizing this property, in the third aspect, the calcium phosphate compound (CPC) and the microorganism 1 are permeated into the sand and solidified over time.
However, the illustrated embodiment is not limited to the above-mentioned three aspects.

In FIG. 8 again, when step S2 is completed, the process proceeds to step S3.
In FIG. 2, which shows step S3 of FIG. 8, the microorganism 1 (for example, urea-degrading bacterium) effective for solidification is separated from the sand 3 collected at the construction site by the microorganism separator R1 (FIG. 1) of the research facility R. Then, the separated microorganism 1 is cultured in the culture solution C (or medium) of the microorganism culture apparatus R2.
The microorganism 1 (for example, urea-degrading bacterium) is cultured until the amount of the microorganism 1 required for the construction set in step S1 is cultivated. A conventionally known technique can be applied to the separation and culturing.

After step S3 in FIG. 8, the process proceeds to step S4.
In step S4, it is determined whether or not the culture of the amount of microorganism 1 required for construction is completed in step S3 with reference to the construction specifications and the like set in step S1.
If the amount of microorganism 1 required for construction has been cultured (Yes in step S4), the process proceeds to step S5.
If the amount of microorganism 1 required for construction has not been cultivated (step S4 is No), the process returns to step S3 and the culturing of microorganism 1 is continued (step S4 is No loop).

In step S5, first, at the construction site, as shown in FIG. 3, the microorganism 1 (for example, including soil) cultured in the sand 3 (including soil in some cases) to be filled in the bag 4 (not shown in FIG. 3) is used. (Urea-degrading bacteria) and the nutrient source (or calcium source) 2 necessary for the microorganism 1 to solidify the sand 3 are mixed. At that time, the cultured microorganism 1 (for example, urea-degrading bacterium), the necessary nutrient source (for example, urea: or calcium source) 2 and sand 3 (including soil and a mixture of soil and sand) are made as uniform as possible. Mix in. However, uniform mixing is not a requirement.
As described above, by supplying the microorganism 1 (for example, urea-degrading bacterium) and the nutrient source (for example, urea: or calcium source) 2 to the sand 3, the microorganism 1 filled in the gap of the sand 3 is caused to solidify. By the solidifying action of the microorganism 1, the sand grains are adhered, the gaps are filled, and the sand 3 is solidified.

Further, in step S5, as shown in FIG. 4, the microorganism 1 (for example, urea-degrading bacteria) and the nutrient source (for example, urea: or calcium source) 2 are mixed, and the mixed sand 3 is filled in the bag 4.
The bag 4 after being filled with sand 3 is, for example, substantially cylindrical, and by stacking a plurality of bags 4, the surface in contact with the adjacent bag 4 is configured to flexibly change its shape (so-called “sandbag”). ").
The size and number of bags 4 filled with the microorganism 1 and the nutrient source (or calcium source) 2 are determined based on the construction specifications set in step S1.

The bag 4 needs to be made of a material that does not allow the filled sand particles to flow out.
As will be described later in step S8 of FIG. 8, the nutrient source (for example, urea: or calcium source) 2 and the microorganism 1 (for example, urea-degrading bacteria) may be supplied from the outside of the bag 4 filled with sand 3 (for example, urea-degrading bacteria). (Refer to FIG. 7 in particular), the material of the bag 4 to have water permeability or a material through which the injection tube needle penetrates is used.
As will be described later, since the sand 3 solidifies with the passage of time, the requirements for the strength and durability of the bag 4 itself are relaxed. The bag 4 may be made of a material that decomposes naturally.

In the illustrated embodiment, the microorganism 1 is mixed with the sand 3 in advance, and the sand 3 mixed with the microorganism 1 is filled in the bag 4. However, after the sand 3 is filled in the bag 4, the bag 4 is filled from the outside of the bag 4. It is also possible to infiltrate the microorganism 1 into the sand 3 through the material of. In this case, the bag 4 is made of a material that allows the microorganism 1 to permeate, or the microorganism 1 is supplied by a chemical injection device (syringe-shaped member).
Further, in the illustrated embodiment, the nutrient source (or calcium source) 2 is mixed with the sand 3 in advance and then filled in the bag 4, but after the sand 3 is filled in the bag 4, the bag 4 is filled from the outside of the bag 4. It is possible to infiltrate the nutrient source (or calcium source) 2 into the sand 3 through the material of. In this case, the bag 4 is made of a material through which the nutrient source (or calcium source) 2 can permeate, or the nutrient source (or calcium source) 2 is supplied by a chemical injection device (syringe-shaped member).

When step S5 of FIG. 8 is completed, the process proceeds to step S6, and as shown in FIG. 5, a bag 4 filled with sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 is placed on the coast or riverbank. As described above, the erosion prevention embankment 10 which is a structure for preventing flood damage is constructed by stacking the areas where there is a risk of being eroded by water (seawater) (areas where flood prevention measures are required). In FIG. 5, reference numeral A indicates a sea or a river, and reference numeral B indicates a coast or a riverbank.
A predetermined number of bags 4 (the number determined in step S1) filled with sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 are stacked so that there is as little gap as possible between them.
Here, when the plurality of bags 4 are stacked, the sand 3 has not solidified, and the shapes of the individual bags 4 are flexible. Therefore, in the step S6, the gap between the bags 4 is formed. It is possible to stack without any.

The erosion prevention bank 10 (structure) constructed by stacking a predetermined number of bags 4 has a height H, a width D (not shown in FIG. 5), and a depth W as determined in step S1. It has a scale, and the depth dimension W decreases as the height dimension H increases. The width dimension D is a direction perpendicular to the paper surface in FIG. 5, and a plurality of bags 4 corresponding to the dimension B are continuously installed in the direction of the width B (direction perpendicular to the paper surface).
Here, if the sand 3 is solidified by the biochemical reaction of the microorganism 1, a gap is formed between the bags 4, so it is preferable that steps S5 to S6 do not last for a long period of time.

After completing the construction of the erosion prevention bank 10 in step S6 of FIG. 8, the process proceeds to step S7, and the bag 4 filled with sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 is appropriately solidified. Check if it is. As described above, "moderately solidifying" means, for example, solidifying to the extent that the strength required for coastal / riverbank conservation can be obtained. It is not a condition that it solidifies uniformly. However, in the implementation, if it does not solidify uniformly, it may be determined that it has not solidified appropriately.
In the above "confirmation" in step S7, the microorganism 1 and the nutrient source (or calcium source) 2 are sanded in consideration of the time required for the sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 to solidify. This is performed after a predetermined time T has elapsed since the mixture was mixed with 3. If the predetermined time T is set to "the time required for the sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 to solidify", the predetermined time T (that is, the solidification time) is filled in the bag 4. It depends on the type of sand 3, the type and amount of microorganism 1 mixed in sand 3, and the type and amount of nutrient source (or calcium source) 2 mixed in sand 3, and is determined on a case-by-case basis. For example, when the microorganism 1 is a urea-degrading bacterium and the nutrient source 2 is urea, the predetermined time T is assumed to be about 1 to 2 weeks.

When confirming whether or not the bag 4 is appropriately solidified, for example, a measuring member capable of confirming the degree of solidification of the sand 3 can be inserted into each bag 4.
Alternatively, the bag 4 in which the microorganism 1 and the nutrient source (or calcium source) 2 are mixed in the sand 3 is extracted as a sample, and it is confirmed whether or not the bag 4 of the sample is appropriately solidified. It is presumed that the sample and the other bag 4 are solidified to the same extent.

As a result of the confirmation in step S7, if the bag 4 filled with the sand 3 in which the microorganism 1 and the nutrient source (or calcium source) 2 are mixed is appropriately solidified (step S7 is Yes), the illustrated embodiment is used. The construction of the flood prevention method is completed.
On the other hand, if the bag 4 filled with the sand 3 in which the microorganism 1 and the nutrient source (or calcium source) 2 are mixed is not appropriately solidified (step S7 is No), the process proceeds to step S8.
In step S8 (when the bag 4 is not properly solidified), as shown in FIG. 6, after the erosion prevention bank 10 is constructed, the sand 3 in the bag 4 has a nutrient source (or calcium source) 2 and / Alternatively, the microorganism 1 is added.

In FIG. 6, a required amount of nutrient source (or calcium source) 2 is used inside the bag 4 (individual bag or all bags) confirmed not to be appropriately solidified by using the chemical injection device 5. Inject. Alternatively (in addition), the chemical infusion device 5 is used to inject the required amount of microorganism 1.
By using the chemical injection device 5, the nutrient source (or calcium source) 2 and / or the microorganism 1 can be efficiently supplied to the deep portion of the bag 4 where the sand 3 is not solidified. ..
Here, in step S8, there are a case where either one of the microorganism 1 and the nutrient source (or calcium source) 2 is injected, and a case where both are injected.
Then, if necessary, a chemical injection device 5 for microorganisms and a chemical injection device 5 for a nutrient source (or calcium source) are separately prepared, and the microorganism 1 and the nutrient source (or calcium source) 2 are separated from each other. It can also be injected using a chemical injection device.

In step S8, in order to add the microorganism 1 and the nutrient source (or calcium source) 2 to the sand 3 in the bag 4 after the construction of the erosion prevention bank 10, the embodiment shown in FIG. 7 is also possible.
In FIG. 7, the chemical spraying device 6 is applied to the bag 4 or all the bags 4 (for example, when it is determined in step S7 that the sample is not appropriately solidified), which is confirmed not to be appropriately solidified. A required amount of nutrient source (or calcium source) 2 and / or microorganism 1 is sprayed from the outside of the bag 4.
In the case of FIG. 7, the bag 4 is made of a water-permeable material.

Microorganisms 1 and nutrient sources (or calcium sources) 2 sprayed from the outer surface of the bag 4 using the chemical spraying device 6 permeate the bag 4 made of a water-permeable material and then permeate the sand 3 in the bag 4. Then, it is supplied to the uncured portion inside the bag 4.
As for the aspect of FIG. 7, similarly to the aspect of FIG. 6, either the microorganism 1 or the nutrient source (or calcium source) 2 may be sprayed using the chemical spraying device 6. If necessary, a chemical spraying device 6 for microorganisms and a chemical spraying device 6 for a nutrient source (or calcium source) are prepared, and the microorganism 1 and the nutrient source (or calcium source) 2 are sprayed separately. The device can be used to spray the bag 4.
After adding the microorganism 1 and the nutrient source (or calcium source) 2 to the sand 3 in the bag 4 in step S8, the process returns to step S7, and after a predetermined time T has elapsed, whether or not the bag 4 is appropriately solidified. To confirm.
In step S8 as well, "moderately solidifying" means, for example, that the strength required for coastal / riverbank conservation can be obtained, and it is not a condition that the solidification is uniform. However, if it does not solidify uniformly, it can be determined that it has not solidified appropriately.

The action and effect of the flood prevention method according to the illustrated embodiment will be described with reference to FIG.
In the conventional technique shown in FIG. 9 (A), the bag 4 may be damaged due to cracks 41 generated in the bag 4 due to the influence of waves, rivers, wind and rain, surrounding dust, mischief by humans, or deterioration over time. There was sex. If the bag 4 is cracked and damaged, the sand 3 filled in the bag 4 will flow out of the bag 4 (arrow F), and as a result, the erosion prevention bank 10 may collapse. did.

On the other hand, in the coast / riverbank conservation method according to the illustrated embodiment, as shown in FIG. 9B, after the erosion prevention bank 10 is constructed by the bag 4 filled with the sand 3, the sand in the bag 4 is constructed. The sand 3 in the bag 4 is solidified by the biochemical activity or metabolism of the nutrient source (for example, urea: or calcium source) 2 and the microorganism 1 (for example, urea-degrading bacteria) mixed in 3.
Therefore, even if the bag 4 is cracked and damaged as shown in FIG. 9A, the sand 3 solidified in the bag 4 does not flow out, and the state of forming the erosion prevention bank 10 can be maintained. .. Then, the erosion prevention bank 10 is maintained for a long period of time after the construction, erosion on the coast or riverbank is prevented, the coast or riverbank is preserved, the landscape is preserved, and flood damage can be prevented.

Further, even if the bag 4 is damaged, the sand 3 solidified in the bag 4 does not flow out and the erosion prevention bank 10 can be maintained, so that it is not necessary to use a bag made of a high-strength and expensive material. .. Further, even if the durability of the bag 4 itself is low, the erosion prevention bank 10 can be maintained for a long period of time.
In addition, a bag 4 made of a naturally decomposable material and a bag 4 made of a material that is decomposed by ultraviolet rays can also be used, and when the bag 4 made of the material is used, the influence on the environment can be further reduced. It can contribute to landscape conservation and nature conservation.

In FIGS. 4 to 9, the bag 4 is filled with sand 3 in which the microorganism 1 and the nutrient source (or calcium source) 2 are mixed, and the bag 4 is laid, laid or stacked to prevent erosion, which is a structure for preventing flood damage. A bank 10 is being built. On the other hand, as shown in FIG. 10, sand mixed with the microorganism 1 and the nutrient source (or calcium source) 2 can be used as the soil covering 20 of the stacked bags 4.
Although not explicitly shown in FIG. 10, the sand filled in the bag 4 may be sand in which the microorganism 1 and the nutrient source (or calcium source) 2 are mixed, or the microorganism 1 and the nutrient source (or the calcium source) are mixed. It may be sand (or soil) that is not mixed with the calcium source) 2.
Although the bags 4 may be stacked as shown in FIG. 10, the bags 4 may be placed in a so-called "flat position".

In FIG. 10, if the soil covering 20 is solidified, even if the bag 4 is cracked and damaged, the sand 3 filled in the bag 4 does not flow out, and the effect of maintaining the erosion prevention bank 10 for a long period of time is effective. It is exhibited well. The same applies when the microorganism 1 and the nutrient source (or calcium source) 2 are not mixed in the sand filled in the bag 4.
Further, it is not necessary to use a bag made of a strong and expensive material, and the durability of the bag 4 itself may be low. Also in this case, a bag 4 made of a naturally decomposable material or a bag 4 made of a material that is decomposed by ultraviolet rays can be used.
Then, the impact on the environment can be reduced to contribute to landscape conservation and nature conservation.
Other configurations and effects in the case shown in FIG. 10 are the same as those described with reference to FIGS. 1 to 9.

It is added that the illustrated embodiment is merely an example and is not a description intended to limit the technical scope of the present invention.

1 ... Microorganism 2 ... Nutrient source (for example, urea) or calcium source 3 ... Sand 4 ... Bag 41 ... Crack 5 ... Chemical injection device 6 ... Chemical spray device 7 ...・ ・ Collection means 10 ・ ・ ・ Erosion prevention embankment (structure)
A ... Sea or river B ... Coast or riverbank C ... Culture solution (or medium)
R ... Research facility R1 ... Microbial separation device R2 ... Microbial culture device

Claims (3)

A step sand (3) which nutrients or calcium source necessary for microorganisms having the property of solidifying (1) and the microorganism (1) to solidify the sand (3) (2) mixed in the sand (3) ,
A step of filling a bag (4) with sand (3) mixed with microorganisms and a nutrient source or a calcium source (2), and
Including the step of stacking bags (4) filled with sand (3) on the shore or the shore of a river to construct a structure (10) for flood prevention.
The bag (4) is a material through which the injection tube needle of the chemical injection device penetrates, and is a flexible material.
After filling the bag (4) with sand (3), if the sand (3) mixed with the microorganism and the nutrient source or the calcium source (2) does not solidify, the microorganism (1) and the nutrient source are used by a chemical injection device. Alternatively , a coast / riverbank conservation method characterized by having a step of supplying a calcium source (2) into a bag (4) . The coast / riverbank conservation method according to claim 1, which includes a step of collecting the microorganisms from a construction site and a step of culturing the collected microorganisms. The coast / riverbank conservation method according to any one of claims 1 and 2, wherein the sand mixed with microorganisms and a nutrient source or a calcium source is used as a soil cover.

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