JP2018025032A - Coastal and riverside conservation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coast / riverbank maintenance method using a bag filled with a filler, in which the effect of coast / riverbank conservation can be maintained even if the bag to be used is damaged, and the manufacturing cost of the bag can be kept low. Providing possible coastal and riverbank conservation methods. According to the coastal / riverbank conservation method of the present invention, a microorganism having the property of solidifying sand (3) (1: for example, a urea-degrading bacterium) and the microorganism (1) solidify the sand (3). A process of mixing the necessary nutrient source (for example, urea: or calcium source 2) into the sand (3), and using the sand (3) for a structure (for coastal / riverbank conservation) (10: for example, an erosion prevention bank). ) To build. [Selection diagram] FIG. 8

Description

  TECHNICAL FIELD The present invention relates to a technique for filling a bag with sand or the like to prevent erosion on a coast or a river and to preserve the scenery and terrain and to prevent flood damage.

When the coastal / river sand and sand are eroded by waves and water currents, sand beach erosion, coastline receding, aesthetics and landscape destruction become problems. And by erosion progressing, it becomes easy to cause water damage. For this reason, the conservation of coasts and river banks has become an important issue.
In the prior art, a bag is filled with soil to create a sandbag, and the sandbags are piled up to prevent coastal / river erosion or water damage prevention structures (for example, erosion prevention dams) to prevent inundation. It is common. And the technique which fills a long cloth bag with local sand, and preserves a coast and a sand beach over a long distance is implemented widely especially overseas.
However, on rough beaches and on shores and riverbanks where there is a lot of garbage, the bags are damaged and the filled soil or local sand flows out. As a result, there are structures that are built by stacking sandbags or bags filled with sand. There is a problem of collapse.
On the other hand, a proposal has been made to use a bag having very high strength and durability to prevent the filled sand from flowing out due to breakage of the bag. However, the bag (the strength and durability are very high). Since the manufacturing cost of the bag) is high, there arises a problem that the construction cost using such a bag increases.

As another conventional technique, a ground improvement method for depositing 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 related to the ground improvement construction method, and is not intended to solve the above-described problems in the coast / river conservation method.
Further, a ground consolidation method has been proposed in which the ground is consolidated by the reaction of carbon dioxide and calcium or the reaction of an alkaline earth metal compound by a biochemical reaction of microorganisms (Patent Document 2). However, this technique (Patent Document 2) is also a technique related to the ground improvement method and is not intended for the coast / river 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 / river conservation method using a bag filled with a filler. The purpose of this project is to provide a coastal and riverside conservation method that can maintain the effect of preventing erosion of earth and sand and keep the manufacturing costs of bags low.

The coast / river conservation method of the present invention is
Microorganisms having a property of solidifying sand (3: including soil in the present invention) (1: urea-decomposing bacteria, etc.) and nutrient sources necessary for the microorganism (1) to solidify sand (3) (for example, urea) ) Or a step of mixing the calcium source (2) into the sand (3);
It is characterized by including a step of constructing a structure (for example, an erosion prevention bank) (for preventing flooding) using the sand (3).

In the present invention, the step of collecting the microorganism (1) from the construction (planned) site;
It is preferable to include a step of culturing the collected microorganism (1) (in an amount necessary for construction).
And it is preferable to include the process of filling a bag with the sand mixed with microorganisms and nutrient source or calcium source (2). The sand-filled bag is used to construct a structure (for preventing flood damage) (10: for example, an erosion prevention bank) (laying, laying or stacking).
Alternatively, it is preferable that the sand mixed with microorganisms and nutrient sources or calcium sources is used as the cover soil (20). In this case, the covering soil (20) is covered by laying, laying or stacking a bag filled with the sand mixed with microorganisms and nutrient sources or calcium sources.
However, even when a bag filled with sand in which microorganisms and nutrient sources or calcium sources are not mixed is laid, laid or stacked, the sand mixed with microorganisms, nutrient sources or calcium sources is used as covering soil (20). Can be covered.
Not only the bags (4) are stacked and covered with the covering soil (20), but the bags (4) may be so-called “flat placed” and covered with the covering soil (20).

  In the present invention, the construction site is preferably a coast or a river shore.

In the present invention, when the sand (3) mixed with microorganisms and nutrient sources or calcium sources (2) does not solidify properly even after a predetermined time (T) has elapsed, the nutrient sources or calcium sources (2 And / or supplying the microorganism (1). Here, “appropriately solidifying” means, for example, that it is hardened to such an extent that a required strength can be obtained, and is not required to be solidified uniformly. However, when it does not solidify uniformly, it can be determined that it has not solidified appropriately.
Here, the predetermined time (T) is mixed in the type of sand (3) filled in the bag (4), the type and amount of the microorganism (1) mixed in the sand (3), and in the sand (3). It is preferably determined on a case-by-case basis depending on the type and amount of the 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 embankment for preventing erosion) is constructed by a bag (4) filled with sand (3: including soil in the present invention). After that, due to the biochemical activity or metabolism of nutrient sources (2: for example urea) or calcium sources (2) and microorganisms (1: for example ureolytic bacteria) mixed in the filling in the bag (4), the bag ( 4) The sand (3) inside is solidified.
Therefore, even if the bag (4) is damaged, the sand (3) solidified in the bag (4) does not flow out, and a state that constitutes a structure for preventing erosion of earth and sand (10: for example, an erosion prevention bank). Can be maintained. And the structure for erosion prevention (10: erosion prevention embankment, for example) is maintained for a long time after the construction, for example, erosion due to waves and water currents on the coast and riverbank is prevented, and the coast and riverbank are preserved. It is possible to protect the landscape and topography and prevent flooding.

And according to the present invention, even if the solidified filling (solidified sand 3) of the bag (4) is disassembled or left standing, the solidified filling is sand (3) collected on site, And since it is solidified by the biochemical action of microorganisms, it does not affect the environment.
In addition, 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. Since it is possible, it is not necessary to use a bag made of a high-strength but expensive material.
Alternatively, even if the durability of the bag (4) itself is low, the structure for preventing erosion of earth and sand (10: for example, an erosion prevention bank) can be maintained for a long period of time.
Further, a bag (4) made of a natural decomposition material and a bag (4) made of a material that decomposes by ultraviolet rays can be used.

And according to the present invention, by solidified by using microorganisms (1), reduces CO ₂ emissions, it is prevented from being contaminated groundwater. Moreover, it is possible to adjust a solidification speed | rate by adjusting the amount of microorganisms (1) and / or the addition amount of a nutrient source or a calcium source (2).
Unlike the case of solidifying with cement or the like, the influence on the environment is very small, and there is little risk of causing environmental destruction. In particular, if a bag made of natural decomposition material (4) or a bag made of material that decomposes by ultraviolet rays (4) is used, it will decompose over time even if such bag (4) is left unattended. Therefore, adverse effects on the natural environment due to the neglected bag are 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) is solidified, the metabolism of the microorganism (1) existing at the construction site Since it is a result, there is little possibility that the biological environment in a construction site will be disturbed by the solidified sand (3).
In other words, from the biological point of view, according to the present invention, the environment of the construction site can be preserved.

It is explanatory drawing which shows the process of extract | collecting the microorganisms which exist in a construction site in embodiment of this invention. It is explanatory drawing which shows the process of culture | cultivating the microorganisms extract | collected at the process shown in FIG. It is explanatory drawing which shows the process of mixing the microorganisms and the nutrient source or calcium source which were cultured in the sand which should be filled into a bag. It is explanatory drawing which shows the process of filling a bag with the sand in which the microorganisms, the nutrient source, or the calcium source were mixed. It is explanatory drawing which shows the process of building up the bank for erosion prevention by stacking the bag filled with sand in the process of FIG. 4 on the shore or the riverbank. It is explanatory drawing which shows the one aspect | mode which supplies a nutrient source or a calcium source, and / or microorganisms in a bag, after building an erosion prevention bank. FIG. 7 is an explanatory view showing an aspect in which a nutrient source or a calcium source and / or microorganisms are supplied into the bag after the erosion prevention dike is built, and is different from FIG. 6. It is a flowchart which shows the operation | movement procedure of illustration embodiment. It is explanatory drawing which shows the effect in embodiment of illustration, (A) shows the case where a bag is damaged in a prior art, (B) shows the case where a bag is damaged in embodiment shown in figure. In embodiment of illustration, it is explanatory drawing which shows the state which used the sand which mixed the microorganisms and the nutrient source or the calcium source as covering soil.

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

For example, the construction position, scale (height, width, depth) of the erosion prevention dike 10 (structure), the size of the bag 4 (bag filled with sand 3) necessary for constructing the erosion prevention dike 10 The total number is set. Further, the amount of sand 3 required, 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 term “sand” is used to include “soil”. Therefore, in the illustrated embodiment, the sand 3 includes soil.
As for the microorganism 1, the microorganisms that inhabit the construction site (the beach, the sea, and the river) are 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.

In step S2 of FIG. 8, as shown in FIG. 1, the sand 3 at the construction site is sampled by the sampling means 7, and necessary microorganisms are extracted and cultured in the research facility R. The research facility R is provided with a microorganism separating device R1 for separating the microorganism 1 from the sand 3 and a microorganism culturing 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 into the sand 3. The sand 3 filled in the bag 4 is solidified by the biochemical activity or metabolism of the microorganism 1.

The aspect which solidifies the sand 3 with which the bag 4 was filled using the microorganism 1 is the same as that of a prior art, for example, there exist the following three types.
As a first aspect, a urea-decomposing 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 hydrolysis action of urea by urea decomposing bacteria, calcium carbonate (CaCO ₃ ) is precipitated between the particles of sand 3 (filled in the bag 4), and the sand particles are adhered and gap-filled. It is a method of solidifying.
The following formulas (1) to (6) show a series of urea hydrolysis reactions by ureolytic bacteria. Calcium carbonate precipitates through the chemical reaction 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)
The pH increase reaction of Formula (3) adjusts to a weakly alkaline environment where calcium carbonate is likely to precipitate, and calcium carbonate (CaCO ₃ ) precipitates according to Formula (6).

In the second embodiment, glucose (C ₆ H ₁₂ O ₆ ) is used as the nutrient source 2, the silica is gelled by the microorganism 1, and a network structure of silica colloid is formed on the sand 3 (packed in the bag 4). It is a method of forming between particles and solidifying.
The following formulas (7) to (10) show chemical reactions until a network structure of silica colloid is formed by 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 (anaerobic condition) (8)
CO ₂ + H ₂ O → HCO ₃ ⁻ + H ⁺ (9)
-Si-OH + HO-Si---Si-O-Si- + H ₂ O (10)
Equation (7), an increase in H ⁺ concentration because the H ⁺ to produce as indicated by the CO ₂ generated in the microbial metabolism of glucose indicated in (8) is dissolved in the silica colloidal solution, equation (9), a solution The pH value inside decreases. As a result, the potential of the silica colloid particle surface changes and condenses, the particles approach each other, and a siloxane bond (-Si-O) that is a dehydration reaction between silanol groups (-Si-OH) on each particle surface. -Si-) occurs (formula (10)), and a network structure of silica colloid is formed.

A third aspect is a method of using a calcium phosphate compound (CPC) as the calcium source 2 and using the microorganism 1 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 hydroxyapatite having high strength with the passage of time. Utilizing such properties, in the third aspect, the calcium phosphate compound (CPC) and the microorganism 1 are infiltrated into the sand and solidified over time.
However, the illustrated embodiment is not limited to the three aspects described above.

In FIG. 8 again, if step S2 is completed, the process proceeds to step S3.
In FIG. 2 showing step S3 in FIG. 8, the microorganisms 1 (for example, urea-decomposing bacteria) effective for solidification are separated from the sand 3 collected at the construction site by the microorganism separation device 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 culture of the microorganism 1 (for example, urea-decomposing bacteria) is performed until the amount of the microorganism 1 necessary for the construction set in step S1 is cultured. In the separation and culture, a conventionally known technique can be applied.

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

In step S5, first, at the construction site, as shown in FIG. 3, the microorganism 1 (for example, cultured in the sand 3 (including soil in some cases) to be filled in the bag 4 (not shown in FIG. 3) is filled. Urea-decomposing bacteria) and a 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-decomposing bacteria), necessary nutrient sources (for example, urea: or calcium source) 2 and sand 3 (including soil, a mixture of soil and sand) are made as uniform as possible. To mix. However, uniform mixing is not a requirement.
As described above, the microorganisms 1 (for example, urea-decomposing bacteria) and the nutrient source (for example, urea: or calcium source) 2 are supplied to the sand 3 to cause the microorganisms 1 filled in the gaps of the sand 3 to have a solidifying action. Due to the solidification action of the microorganisms 1, the sand particles are adhered and gap-filled, and the sand 3 is consolidated.

Furthermore, in step S5, as shown in FIG. 4, the microorganism 1 (for example, urea decomposing 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 the sand 3 has, for example, a substantially columnar shape, and is configured so that the surface in contact with the adjacent bag 4 is flexibly changed by stacking a plurality of bags 4 (so-called “sandbag” ").
The size and number of the bags 4 filled with the microorganisms 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 from which the filled sand particles do not flow out.
As will be described later in step S8 of FIG. 8, there are cases where nutrient sources (for example, urea: or calcium source) 2 and microorganisms 1 (for example, urea-decomposing bacteria) may be supplied from the outside of the bag 4 filled with sand 3 ( In particular, see FIG. 7), and the material of the bag 4 is a material having water permeability or a material through which the injection tube needle penetrates.
As will be described later, since the sand 3 is solidified over time, 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 microorganisms 1 are mixed with the sand 3 in advance, and the sand 3 mixed with the microorganisms 1 is filled in the bag 4. After the sand 3 is filled in the bag 4, the bag 4 is formed from the outside of the bag 4. It is also possible to infiltrate the microorganisms 1 into the sand 3 through these materials. In this case, the bag 4 is made of a material through which the microorganism 1 can permeate, or the microorganism 1 is supplied by a chemical solution injection device (a syringe-like member).
Further, in the illustrated embodiment, the nutrient source (or calcium source) 2 is mixed with the sand 3 in advance and then filled into the bag 4. However, after the sand 3 is filled into the bag 4, the bag 4 is loaded from the outside of the bag 4. It is possible to infiltrate the sand 3 with the nutrient source (or calcium source) 2 through the material. 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 solution injection device (a syringe-like member).

If step S5 of FIG. 8 is completed, it will progress to step S6, and as shown in FIG. 5, the bag 4 filled with the sand 3 in which the microorganism 1 and the nutrient source (or calcium source) 2 were mixed, In the same manner, the erosion prevention dike 10 which is a structure for preventing water damage is built up in an area where water (seawater) may be eroded (area where water damage prevention measures are required). In FIG. 5, symbol A indicates the sea or river, and symbol B indicates the coast or river bank.
A predetermined number (the number determined in step S1) of the bags 4 filled with the sand 3 mixed with the microorganisms 1 and the nutrient source (or calcium source) 2 is stacked so that there is no gap between them.
Here, when the plurality of bags 4 are stacked, the sand 3 is not solidified, and the shape of each bag 4 is flexible. It is possible to stack without any.

The erosion prevention dike 10 (structure) built 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. The depth dimension W decreases as the height dimension H increases. In addition, the width dimension D is a direction perpendicular | vertical to a paper surface in FIG. 5, and the several bag 4 according to the dimension B is continuously installed in the direction of the width B (direction perpendicular | vertical to a paper surface).
Here, when the sand 3 is solidified by the biochemical reaction of the microorganism 1, a gap between the bags 4 is generated. Therefore, it is preferable that the step S5 to the step S6 do not take a long 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 the sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 is solidified appropriately. Check if it is. As described above, “appropriately solidifying” means, for example, that it is hardened to such an extent that the strength required for coastal / river conservation is obtained. It does not require a uniform solidification. However, in the implementation, it may be determined that the solidification is not appropriate when it does not solidify uniformly.
In the “confirmation” in step S7, considering the time required for the sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 to solidify, the microorganism 1 and the nutrient source (or calcium source) 2 are sanded. 3 is carried out after a predetermined time T has elapsed since mixing in the mixture 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 microorganisms 1 mixed in the sand 3, and the type and amount of nutrient source (or calcium source) 2 mixed in the sand 3. For example, when the microorganism 1 is a urea-decomposing 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 solidified appropriately, 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 latest microorganism 1 and 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 solidified appropriately. It is assumed 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 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 is solidified appropriately (step S7 is Yes), the illustrated embodiment is used. Construction of the flood prevention method is complete.
On the other hand, if the bag 4 filled with the sand 3 mixed with the microorganism 1 and the nutrient source (or calcium source) 2 is not solidified appropriately (No at Step S7), 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 nutrient 3 (or calcium source) 2 and / or the sand 3 in the bag 4 is added. Alternatively, the microorganism 1 is added.

In FIG. 6, a necessary amount of nutrient source (or calcium source) 2 is stored inside the bag 4 (individual bag or all bags) that has not been solidified appropriately by using the chemical injection device 5. Inject. Alternatively (in addition to that), the chemical solution injection device 5 is used to inject a necessary amount of the 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 portion of the sand 4 in which 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.
If necessary, the chemical solution injection device 5 for microorganisms and the chemical solution injection device 5 for nutrient sources (or calcium sources) are prepared separately, and the microorganism 1 and the nutrient source (or calcium source) 2 are separately provided. It can also inject | pour using a chemical | medical solution injection apparatus.

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 in step S8, the mode shown in FIG. 7 is also possible.
In FIG. 7, the chemical solution spraying device 6 is applied to the bag 4 or all the bags 4 that have been confirmed not to be solidified properly (for example, when it is determined in step S7 that the sample has not been solidified appropriately). The necessary 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 sand 3 in the bag 4 after passing through the bag 4 made of water-permeable material. And supplied to the unsolidified portion inside the bag 4.
Also in the embodiment of FIG. 7, as in the embodiment 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 solution spraying device 6 for microorganisms and a chemical solution spraying device 6 for nutrient sources (or calcium sources) are prepared, and the microorganism 1 and the nutrient source (or calcium source) 2 are sprayed separately. It can be applied to the bag 4 using the device.
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 whether or not the bag 4 is solidified appropriately after a predetermined time T has elapsed. Confirm.
Also in step S8, “appropriately solidifying” means, for example, that it is hardened to such an extent that strength necessary for coastal / river bank preservation can be obtained, and does not require uniform solidification. However, when it does not solidify uniformly, it can be determined that it has not solidified appropriately.

The effect of the flood prevention method according to the illustrated embodiment will be described with reference to FIG.
In the prior art shown in FIG. 9A, a crack 41 may be generated in the bag 4 due to waves, rivers, wind and rain, surrounding garbage, mischief by people, or deterioration over time, and the bag 4 may be damaged. There was sex. If the crack 4 occurs in the bag 4 and breaks, the sand 3 filled in the bag 4 flows 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 / river conservation method according to the illustrated embodiment, as shown in FIG. 9B, after the erosion prevention dike 10 is constructed with the bag 4 filled with the sand 3, the sand in the bag 4 is sanded. 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-decomposing bacteria) mixed in 3.
Therefore, even if a crack 41 occurs and breaks in the bag 4 as shown in FIG. 9A, the sand 3 solidified in the bag 4 does not flow out, and the state constituting the erosion prevention dike 10 can be maintained. . Then, the erosion prevention dike 10 is maintained for a long period after the construction, and erosion on the coast and riverbank is prevented, and the coast and riverbank are preserved, and the landscape can be 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 high-strength and expensive material. . Furthermore, even if the durability of the bag 4 itself is low, the erosion prevention bank 10 can be maintained over a long period of time.
In addition, it is possible to use a bag 4 made of a natural decomposition material or a bag 4 made of a material that decomposes by ultraviolet rays. 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, sand 3 mixed with microorganisms 1 and nutrient sources (or calcium sources) 2 is filled in a bag 4, and the bag 4 is laid, laid or stacked to prevent erosion, which is a structure for preventing water damage. The dyke 10 is 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 covering soil 20 of the stacked bags 4.
Although not clearly shown in FIG. 10, the sand filled in the bag 4 may be sand mixed with the microorganism 1 and the nutrient source (or calcium source) 2, or the microorganism 1 and the nutrient source (or It may be sand (or soil) in which calcium source 2 is not mixed.
Although the bags 4 may be stacked as shown in FIG. 10, the bags 4 may be so-called “flat”.

In FIG. 10, if the cover soil 20 is solidified, even if the bag 4 is cracked and broken, the sand 3 filled in the bag 4 does not flow out, and the effect of maintaining the erosion prevention dike 10 for a long period of time is obtained. Good performance. 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.
Moreover, 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. Even in this case, a bag 4 made of a natural decomposition material or a bag 4 made of a material that decomposes by ultraviolet rays can be used.
And it can contribute to the preservation of the landscape and the conservation of nature by reducing the impact on the environment.
Other configurations and operational effects in the case shown in FIG. 10 are the same as those described with reference to FIGS.

  It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Microorganism 2 ... Nutrient source (for example, urea) or calcium source 3 ... Sand 4 ... Bag 41 ... Crack 5 ... Chemical solution injection device 6 ... Chemical solution spraying device 7. ..Collecting means 10 ... Erosion prevention dike (structure)
A ... Sea or river B ... Coast or river C ... Culture medium (or medium)
R ... Research facility R1 ... Microbe separation device R2 ... Microbe culture device

Claims (6)

Mixing a microorganism having a property of solidifying sand and a nutrient source or a calcium source necessary for the microorganism to solidify the sand;
A coastal and riverside conservation method characterized by including a process of constructing a structure using the sand.   The coast / river conservation method according to claim 1, comprising a step of collecting the microorganisms from a construction site and a step of culturing the collected microorganisms.   The coastal / riverside conservation method according to claim 1, comprising a step of filling a bag with the sand mixed with microorganisms and nutrient sources or calcium sources.   The coast / river conservation method according to any one of claims 1 and 2, wherein the sand mixed with microorganisms and nutrient sources or calcium sources is used as cover soil.   3. The coast / river conservation method according to claim 1, wherein the construction site is a coast or a river shore.   4. The method according to claim 3, further comprising the step of supplying the nutrient source or calcium source and / or the microorganism when the sand mixed with the microorganism and nutrient source or calcium source does not solidify properly even after a predetermined time has elapsed. The coast / river conservation method according to any one of items 5.

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