JP2005232739A - Sediment flow-out preventing method and sediment flow-out preventing agent spraying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sediment flow-out preventing method and a sediment flow-out preventing agent spraying device for preventing the flow-out of sediment by low-cost simple construction. <P>SOLUTION: The sediment flow-out preventing agent spraying device 1 comprises a fiber material storage tank 2 for storing fiber materials which cover a soil surface, a fiber material spray part 3 connected to the lower part of the fiber material storage tank 2 for spraying the fiber materials, a solidifying agent storage tank 4 for storing a solidifying agent to be sprayed on the soil surface on which the fiber materials are sprayed, and a solidifying agent spray nozzle 5 for spraying the solidifying agent provided in the solidifying agent storage tank 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a construction method and apparatus for preventing the outflow of earth and sand in the ground.

  The ground containing a lot of red soil and mudstone has a lot of ground with poor water resistance, and there is a problem that soil and sand are likely to flow out due to the impact of rainfall and raindrops. In particular, the red soil that is widely distributed in Okinawa Prefecture flows out into the sea and deposits on the bottom of the sea to drive the bottom organisms that have been responsible for the purification of seawater to death, or the red soil that has flowed out is swept away by tides and strong winds. It spreads in coral reef waters and gradually kills corals.

In order to solve such a sediment runoff problem, a soil aggregating agent or asphalt emulsion is sprayed on the soil (see JP-A-8-134886), the soil is covered with a sheet, or vegetation has been performed. It was. In addition, measures have been taken to post-process turbid water generated by rainfall.
JP-A-8-134886

  However, these methods are costly but cannot sufficiently prevent the outflow of earth and sand. Moreover, the muddy water treatment is performed after the fact, and the outflow of earth and sand cannot be prevented in advance, and damage such as environmental destruction due to muddy water cannot be prevented.

  Then, this invention makes it a subject to provide the earth and sand outflow prevention construction method and the earth and sand outflow prevention agent dispersal which can prevent the outflow of earth and sand by low-cost and simple construction.

  This invention is made | formed in view of the said matter, and this invention is a construction method which prevents the outflow of earth and sand including the process of spraying the solidification agent which solidifies earth and sand on the soil surface.

  The solidifying agent according to the present invention includes a curing agent mainly composed of light-burned magnesia that hardens earth and sand, a dispersing agent that maintains a suspension state of the curing agent, and an adhesion state to the soil surface when the curing agent is cured. And a binder that regulates. As the dispersant, a composition (compound) mainly composed of carboxymethyl cellulose (CMC) can be suitably used. In addition, when the target ground is a compacted ground, a composition containing ethylene / vinyl acetate copolymer (EVA) as the main component to improve the adhesion to the soil surface when the suspension is hardened. It is preferable to add a (compound) binder. Note that the binder may or may not be used depending on the state of the soil.

  Thus, by covering the ground surface with a solidifying agent (hardening agent), it is possible to prevent erosion due to raindrops and finening of soil particles and to make it difficult for soil to flow out.

  In addition, the solidifying agent (or hardener) layer (hereinafter referred to as a mulching layer) formed by the present invention is not a water-shielding layer but a soil particle while maintaining a gap between soil particle blocks. Coat the mass. For this reason, it is possible to avoid excessively reducing the permeability of the ground and impeding the penetration of rainwater more than necessary.

Furthermore, when the solidifying agent according to the present invention is solidified (cured), its pH is in the range from neutral to weakly alkaline. Therefore, it can be said that the solidified solidifying agent of the present invention has a low impact on the environment and a high safety compared to a hardened cement that exhibits strong alkalinity.

  Moreover, the earth and sand outflow prevention construction method of this invention may include the process of spraying the coating | covering material which covers the soil surface. This covering material is preferably a fiber material mainly composed of bagasse. Bagasse is sugarcane squeezed. Examples of other fiber materials include bamboo and vegetation fibers.

  By spreading the fiber material on the ground surface, the cushioning property against rain (raindrops) can be increased, and the ground surface covering state by the solidifying agent can be improved. Moreover, since bagasse used for the fiber material is a natural fiber, there is no risk of soil contamination.

  Further, the present invention is characterized by comprising a solidifying agent storage tank that stores a solidifying agent that solidifies the soil surface in order to prevent the outflow of earth and sand, and a solidifying agent spraying means that sprays the solidifying agent onto the soil surface. To do. In addition, it is more preferable that a covering material storage tank for storing the covering material covering the soil surface and a covering material spraying means for spraying the covering material are provided.

  According to this apparatus, even in a narrow place where a large apparatus cannot be inserted, the worker can manually spray the solidifying agent on the soil surface. Of course, the sediment spillage preventing agent spraying device of the present invention is configured to load at least the solidifying agent storage tank and the solidifying agent spraying means on the vehicle among the solidifying agent storage tank, the solidifying agent spraying means, the covering material storing tank, and the covering material spraying means. It is good also as a structure. Thereby, the work which prevents the outflow of earth and sand to a vast land can be performed efficiently. In addition, a construction apparatus for a plane simply attaches an attachment in which nozzles for dispersing a solidifying agent are arranged in parallel or a component (apparatus) for spreading fiber material to a general-purpose in-vehicle spreader (vehicle). Therefore, it can be used for general-purpose machines.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the earth and sand outflow prevention construction method and earth and sand outflow prevention agent spraying apparatus which can prevent the outflow of earth and sand with low-cost and simple construction.

  Hereinafter, the earth and sand spill prevention method and the earth and sand spill prevention agent spraying device of this embodiment will be described with reference to the drawings.

<Structure of earth and sand spill prevention agent spraying device>
FIG. 1 shows a structural diagram of a sediment discharge agent spraying device 1 according to this embodiment.

  Moreover, the earth and sand spill prevention agent spraying device 1 of this embodiment is connected to a fiber material storage tank (covering material storage tank) 2 for storing a fiber material (covering material) covering the soil surface, and a lower part of the fiber material storage tank 2. A fiber material spraying unit (coating material spraying means) 3 for spraying the fiber material (coating material), a solidifying agent storage tank 4 for storing the solidifying agent sprayed on the soil surface on which the fiber material is sprayed, and a solidifying agent A solidifying agent spraying nozzle (solidifying agent spraying means) 5 for spraying the solidifying agent provided in the storage tank 4 is provided.

  The solidifying agent storage tank 4 and the solidifying agent spray nozzle 5 are connected by a pipe 7 via a slurry pump 6. The slurry pump 6 sucks out the solidifying agent stored in the solidifying agent storage tank 4 and ejects it from the solidifying agent spray nozzle 5.

As shown in FIG. 2, the solidifying agent spray nozzle 5 is a nozzle that spreads the ejected solidifying agent into a fan shape. The solidifying agent spray nozzle 5 of this embodiment is 50 cm (from the injection port of the solidifying agent spray nozzle 5 (
The solidifying agent can be sprayed at a position L) in FIG. 2 with a spray width (M in FIG. 2) of 100 cm. The solidifying agent spray nozzle 5 of the present embodiment has three nozzles arranged in parallel, and the solidifying agent spray width (N in FIG. 2) ejected from the three nozzles is 260 cm.

  As shown in FIG. 1, the pipe 7 has a switching valve 8 near the slurry pump 6, and an open / close valve 9 near the solidifying agent spray nozzle 5. The switching valve 8 switches between the case where the solidifying agent is sprayed and the case where the material is mixed by returning to the tank. Moreover, the on-off valve 9 adjusts the ejection amount of the solidifying agent.

  The fiber material according to this embodiment is bagasse (sugar cane residue). The bagasse used for the fiber material is a natural fiber, so the possibility of soil contamination is extremely low. Furthermore, using bagasse as a fiber material also means reusing materials that are no longer needed. Therefore, it is also environmentally friendly and can prevent sediment from flowing out at low cost.

  The solidifying agent storage tank 4 has a stirring blade (not shown) for stirring the solidifying agent that is a suspension. The solidifying agent according to the present embodiment is mainly composed of a light-burning magnesia curing agent that hardens the earth and sand, a dispersing agent that maintains a suspension state of the curing agent, and an adhesion state to the soil surface when the curing agent is cured. And a binder that regulates. In this embodiment, the dispersant is a composition (compound) containing carboxymethyl cellulose (CMC) as a main component. In addition, the binder in the present embodiment is a composition (compound) having an ethylene / vinyl acetate copolymer (EVA) as a main component.

  The above is the structure of the earth and sand runoff preventing agent spraying apparatus 1 of the present embodiment. In addition, the earth and sand runoff prevention agent spraying apparatus 1 of this embodiment is mounted in vehicles, such as a truck, as shown in FIG. By placing the earth and sand spill prevention agent spraying device 1 on the vehicle, the solidifying agent and / or the fiber material can be sprayed well on a vast flat ground.

<Sediment prevention method>
Next, the earth and sand outflow prevention construction method using the earth and sand outflow prevention agent spraying apparatus 1 is demonstrated. In the following description, it is assumed that the solidifying agent is sprayed on the flat ground.

  First, a fiber material is sprayed from the fiber material spraying unit 3 to cover the soil surface. Then, the solidifying agent is ejected from the solidifying agent spray nozzle 5 onto the fiber material.

  Thus, by dispersing the solidifying agent from above the fiber material, cushioning against rain (raindrops) is increased, and the ground surface covering state with the solidifying agent can be improved.

  Moreover, when a solidifying agent is sprayed on the ground, the ground is coated with the solidifying agent to form a mulching layer. The mulching layer is able to avoid excessively reducing the permeability of the ground and preventing rainwater from penetrating more than necessary. That is, by spraying the fiber material and the solidifying agent, it is possible to form a ground that is difficult for sediment to flow out and is water resistant.

  The above is the earth and sand outflow prevention construction method of this embodiment. Next, three tests carried out to clarify how much sediment discharge can be prevented by the sediment discharge agent spraying device 1 and the sediment discharge prevention construction method in this embodiment will be described.

(Test Example 1)
FIG. 3 shows a blending table of solidifying agents and fibers used in the test (Test Example 1). Case 1 is a case where the ground sediment prevention method is not applied to the ground, and Case 2 is applied with 2 liters / m ^{2 of a} solidifying agent consisting of a hardener: 0.3 kg / m ² and CMC: 0.008 kg / m ² , In case 3 the curing agent: 0.6 kg / m ^2, CMC: 0.016 kg / m ² composed of the solidifying agent from 4 l / m ² by spraying, casing 4, curing agent: 0.6 kg / m ^2, CMC: 0 and .016Kg / m ² made of a solidifying agent, fiber materials: 0.04 kg / m ² and 4 l / m ² sprayed together, case 5 in the curing agent: 0.6 kg / m ^2, CMC: 0.016 kg The solidifying agent composed of / m ² and the fiber material: 0.1 kg / m ² were combined and sprayed at 4 liters / m ² . If Case 2 is a basic case, Case 3 is a case where the solidifying agent of Case 2 is sprayed twice, and Case 4 and Case 5 are cases where the mixing amounts of fiber materials are different.

  Thus, the solidification agent and fiber material which changed the blending ratio were sprayed on a 1 m × 5 m test yard (test ground), and 50 mm / h-class rain was simulated in the test yard. By measuring the amount of suspended solids (SS) contained in the effluent water flowing out at that time, the degree of the effect of the sediment spill prevention construction in the present embodiment is determined.

  Then, as shown in FIG. 4, in the case 1 where no countermeasure was taken against the outflow of earth and sand, the amount of suspended solids was 1100 ppm.

  However, in case 2 where only 2 liters of solidifying agent was sprayed on the test yard, the amount of suspended solids was 400 ppm. Furthermore, in case 3 where only 4 liters of solidifying agent was sprayed on the test yard, the amount of suspended solids was 100 ppm.

  In addition, in case 4 in which fiber material was sprayed in addition to the solidifying agent, the amount of suspended solids was less than 100 ppm, and in case 5 it was about 50 ppm.

  From the above result, it becomes clear that the sediment discharge prevention construction method by the sediment discharge agent spraying device 1 of the present embodiment suppresses sediment discharge.

  In construction projects, the amount of suspended solids is often determined to be 200 ppm or less. That is, according to the earth and sand spill prevention method by the earth and sand spill prevention agent spraying device 1 of the present embodiment, it is possible to obtain a high quality ground that can also clear the standards of the construction business. Moreover, using bagasse for the fiber material means reusing resources that are no longer needed. Therefore, the fiber material can be provided at low cost.

(Test Example 2)
In this test, a solidifying agent is sprayed on a 5 m × 10 m test yard on soil in Ishigaki City, Okinawa Prefecture, and left under natural conditions for 10 months. And the amount of earth and sand which flows out in the case of the actual rainfall by the typhoon etc. in the test yard is measured, and the grade of the effect of the earth and sand outflow prevention construction in this embodiment is determined.

FIG. 5 shows a blending table of solidifying agents used in this test. Case 1 is a case that does not spread the solidifying agent to the soil of only Kakiokoshi soil, case 2 to ground which Kakiokoshi soil, curing agent: 0.6 kg / m ² and CMC: 0.016 kg / m ² Case 3 is a case in which 4 liters of solidifying agent containing is sprayed, and Case 3 is hardened: 0.6 kg / m ² , CMC: 0.016 kg / m ² and binder (EVA): 0.02 kg on the compacted ground. / m ² Metropolitan consisting solidifying agent is 4 liters sprayed cases. Case 2 assumes agricultural land, and Case 3 assumes earthwork. In addition, spraying a solidifying agent or fiber material on soil is called liquid mulching.

FIG. 6 shows a graph of rainfall intensity in this test. This graph is a measurement result of rainfall intensity over 10 days from May 10 to May 19. From this graph, it can be seen that on May 15, there was 40 mm / h of rain under natural conditions, and on May 17, there was 6,7 mm / h of rain and 35 mm / h of rain.

  7 to 9 show the measurement results of the amount of suspended solids contained in the outflow water flowing out from the test yard at the date and time corresponding to the rainfall intensity graph of FIG. Incidentally, the standard amount of suspended solids in the effluent is 200 ppm.

  First, as shown in FIG. 7, about 700 ppm of suspended solids were measured on the ground in Case 1 on May 15 and May 17 when there was rainfall. The amount of suspended solids at 700 ppm far exceeds the standard value of 200 ppm, and it can be determined that sediment runoff is significant.

  Moreover, as shown in FIG. 8, in case 2, the amount of suspended solids on May 15 and May 17 where heavy rain occurred was 50 to 70 ppm, both being lower than the standard value.

  Furthermore, as shown in FIG. 9, also in case 3, the amount of suspended solids in the effluent on May 15 and May 17 where there was strong rainfall was 50 to 80 ppm, which was almost the same value as in case 2 became.

  Thereby, it turns out that the earth-and-sand outflow prevention construction method by the earth-and-sand outflow prevention agent spraying apparatus 1 of this embodiment acts effectively also on the soil which has many red soils in Ishigaki-shi, Okinawa Prefecture. That is, according to the earth and sand outflow prevention construction method by the earth and sand outflow prevention agent spraying apparatus 1 of this embodiment, damage, such as environmental destruction by the muddy water of red soil, can be prevented.

(Test Example 3)
This test is a water permeability test of soil sprayed with the solidifying agent according to the present embodiment. In the water permeability test, soil is placed in a container with a water flow surface on the top and bottom surfaces, a solidifying agent is sprayed on the surface of the soil, water is passed from the top surface, the elapsed time up to a predetermined time and water drained from the bottom surface. It is a test to find the hydraulic conductivity of the ground from the amount of the soil. In this test, the container was filled with soil loosely (1.5 g / cm ³ ) so as to increase the space between the soil particles, and the space between the soil particles was decreased. The test was conducted with two models, one with soil (1.7 g / cm ³ ) and the other with soil.

FIG. 10 shows the results of the water permeability test. Then, even if there were many voids between soil particles and those with few voids, even if 2 to 4 liters / m ^{2 of} solidifying agent was sprayed, the water permeability coefficient was not significantly reduced.

  Thereby, even if the solidifying agent according to the present embodiment is sprayed on the soil, it can be confirmed that appropriate water permeability can be maintained.

  As described above, according to the earth and sand spill prevention method 1 by the earth and sand spill prevention agent spraying device 1 of the present embodiment, the soil having poor water resistance with a large amount of earth and sand spilling is maintained with a small amount of earth and sand and an appropriate water permeability. Can be improved to good quality soil.

  Moreover, the earth and sand outflow prevention construction method and earth and sand outflow prevention agent spraying apparatus of this embodiment mentioned above are examples, and are not restricted to the form mentioned above. For example, as a sediment discharge agent spraying device of another embodiment, a solidifying agent storage tank that stores a solidifying agent that solidifies the sediment to prevent the sediment from flowing out, and a solidifying agent spray nozzle that sprays the solidifying agent on the soil surface And a device provided with (solidifying agent spraying means). In the case of an apparatus having such a configuration, a worker holds the apparatus and sprays a solidifying agent on the soil surface by human power. As a result, it is possible to prevent the outflow of earth and sand such as a narrow place where a vehicle cannot enter or a debris. In addition, when a covering material storage tank (fiber material storage tank) for storing a covering material (fiber material) covering the soil surface and a covering material spraying means (fiber material spraying section) for spraying the covering material are added to this configuration More preferred.

1 is an overall view of a sediment discharge agent spraying device of an embodiment. It is an enlarged view of the solidification agent spraying nozzle which concerns on this embodiment. 4 is a table showing the content of a solidifying agent in Test Example 1. 6 is a graph showing test results in Test Example 1. It is a table | surface which shows the test conditions in Test Example 2, and the content of a solidifying agent. 5 is a graph showing rainfall intensity in Test Example 2. It is a graph which shows the amount of suspended solids in the ground without measures. It is a graph which shows the amount of suspended solids in cultivated land. It is a graph which shows the amount of suspended solids in a rolling compaction ground. 10 is a graph showing test results in Test Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sediment runoff sprayer 2 Fiber material storage tank 3 Fiber material spray part 4 Solidifying agent storage tank 5 Solidifying agent spray nozzle 6 Slurry pump 7 Pipe 8 Switching valve 9 Opening and closing valve

Claims (9)

A construction method that prevents the outflow of earth and sand,
Including a step of spreading a solidifying agent for solidifying the soil on the soil surface;
A method for preventing sediment from flowing out, characterized in that the solidifying agent contains light-burned magnesia as a main component.   The method according to claim 1, further comprising a step of spraying a covering material covering the soil surface.   The method according to claim 1 or 2, wherein the covering material is a fiber material mainly composed of bagasse. The solidifying agent is mainly composed of a curing agent that hardens earth and sand,
The dispersion agent which maintains the suspension state of the said hardening | curing agent, and / or the binder which adjusts the adhesion state to the soil surface when the said hardening | curing agent hardens | cures are contained, In any one of Claims 1-3 characterized by the above-mentioned. Debris runoff prevention method described.   The earth and sand runoff prevention method according to any one of claims 1 to 4, wherein the dispersant contains carboxymethyl cellulose as a main component.   The earth and sand outflow prevention method according to any one of claims 1 to 5, wherein the binder contains an ethylene / vinyl acetate copolymer as a main component. A solidifying agent storage tank for storing a solidifying agent that solidifies the soil surface to prevent the outflow of earth and sand;
Solidifying agent spraying means for spraying the solidifying agent on the soil surface;
An earth and sand spill prevention agent spraying device characterized by comprising: A covering material storage tank for storing a covering material covering the soil surface;
A coating material spraying means for spraying the coating material;
The earth and sand spill prevention agent spraying device according to claim 7 characterized by things.   The earth and sand spill prevention agent spraying device according to claim 7 or 8, further comprising a mobile vehicle on which the solidifying agent storage tank, the solidifying agent spraying means, the coating material storage tank, and the coating material spraying means are loaded.

Images