JP2009121173A - Ground coating work and ground coating construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ground coating work and a ground coating construction method which make possible execution by spraying, which are excellent in weatherability, and which can maintain a herbicidal effect over a long time period. <P>SOLUTION: A flocculent short fiber of bamboo, a hardening agent, and a spraying agent 31 containing a fine aggregate are mixed with water. The flocculent short fiber of bamboo is formed by pressing and crushing bamboo grass or the like material, and the hardening agent contains magnesium oxide of seawater origin. Then the spraying agent 31 mixed with water is sprayed on the execution ground by pressurization air without creating any clearance, and is individualized. Thus, a root-blocking layer 38 is formed which blocks the passage of a root of plants. The short fiber of bamboo functions as a buffer, and prevents cracking at the time of hardening-expansion of the magnesium oxide. Then the toughness/water-retentivity of the root-blocking layer 38 can be improved. The use of the seawater origin prevents the inclusion of a toxic substance such as arsenic, and makes possible recycling as fertilizer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ground covering work for suppressing the growth of weeds such as a slope on a roadside and a construction method thereof.

  Conventionally, for the purpose of stabilizing the slope and preventing grass, slope protection works have been carried out in various places to spray mortar on the slope. However, the mortar spraying has a problem that the sprayed mortar stands out in white compared to the surrounding soil color and the natural landscape is destroyed. Therefore, in recent years, in slope construction, the mortar spraying that completely covers the slope with mortar has been avoided due to the social situation that emphasizes environmental conservation, and a vegetation base sprayer that greens the slope may be adopted. It is getting more. However, in the vegetation base material spraying work, the slope is eventually covered with foreign plants (weeds) as time passes, which is not preferable in view of the landscape. Therefore, recently, a project to plant a seedling of a local species tree to be grown has been actively carried out on the slope. However, these native species trees grow slower than weeds and ivy (such as kudzu, wisteria, etc.), so regular weeding work is necessary until they grow sufficiently, and maintenance costs are incurred. Is a problem.

  On the roadside slope formed by embankment or the like, the plant grows over the years after the completion of construction, which obstructs the visibility of the traveling vehicle and prevents pedestrians and bicycles from passing. Another problem is that if weeds and ivy grow on the shoulder, fires are likely to occur due to the thrown tobacco. Therefore, road management such as frequent weeding is required particularly in rural areas and mountainous areas.

  Therefore, in recent years, we have adopted a herbicide that suppresses the growth of unnecessary plants by covering the ground such as slopes with a herbicidal material in order to suppress the growth of unnecessary plants such as weeds and ivy on the slope. It has come to be. As such a herbicidal work, it is roughly divided into a structure (hereinafter referred to as “surface covering herbicidal work”) in which the ground is covered with a sheet-like or panel-like covering material such as a herbicidal sheet or a herbicidal panel. A structure in which the ground surface is hardened by spraying a coagulant such as mortar to form a herbicidal layer (hereinafter referred to as “surface hardening herbicide”) is known.

  In the surface covering herbicide, a herbicidal sheet, a herbicidal panel, a herbicidal block or the like is used as a covering material. As the weedproof sheet, rubber or plastic sheets that do not allow light to pass through, and felt sheets (mats) such as hemp, cotton, regenerated fiber, synthetic fiber, etc. are used. The thing which can prevent the germination of is used (refer patent documents 1-5). When using a weedproof sheet, lay a weedproof sheet on the road shoulder slope, and fix the edge and a predetermined part of the inside with an anchor pin (see Patent Documents 1-4), or stone on the upper surface of the weedproof mat Secure the weedproof mat by spreading gravel and other weights. Moreover, as a weedproof panel, a concrete panel (patent documents 6, 7, 15), a WPC (Wood-Plastic Combination) panel (patent document 8), a wood panel (biomass board) (nonpatent literature 1, patent documents 9, 10) and the like are used, and a herbicidal effect is obtained by spreading them on the slope without any gaps. Moreover, concrete and wood (refer patent document 11) are used as a weedproof block, and the weedproof effect is acquired by spreading these on the slope without gap.

  On the other hand, in the case of surface-cured herbicide, a curing agent containing a water-curable binder is laid on the entire surface or almost the entire surface of the enforcement site, such as the road shoulder slope, and cured to the extent that weeds do not grow on the surface of the enforcement site. A hardened layer is formed to obtain a herbicidal effect. In general, mortar, concrete, soil cement and the like are widely used as the curing agent. However, as described above, the mortar only sprayed with mortar is whiter than the surrounding soil color, and there is a problem of landscape destruction. A method of producing a color close to is adopted.

  In Patent Document 12, inorganic fibers (rock wool, slug wool, glass wool, ceramic fibers, etc.) and inorganic hydraulic binders (Portland cement, blast furnace cement, white cement, gypsum, lime, slag-gypsum, alum-lime A surface hardening herbicide in which an inorganic material mainly composed of a system, plaster or the like) and water are sprayed and integrated on the entire surface or almost the entire surface of the construction site is described.

  In Patent Document 13, a small amount of cement and aggregate are added to natural soil to produce a granule having a predetermined particle size distribution, and a binder is coated on the surface of the granule. A surface-hardening herbicide is described which is formed by laying at the place of enforcement and rolling the surface.

  In Non-Patent Document 2, root stocks and branches and leaves generated in the construction site are chipped, mixed with cement to form soil cement, and foam glass and zeolite are mixed as auxiliary aggregates and sprayed onto the road shoulder slope. A surface hardening herbicide is described.

  Non-patent documents 3 and 14 include magnesium oxide and different metal salts (magnesium sulfate, magnesium hydroxide, magnesium chloride, calcium sulfate, aluminum sulfate, ferrous sulfate, polyaluminum chloride, alum, and calcined alum. 1) or a combination of two or more selected from stone, superphosphate, and zinc sulfate), and after laying uniformly on the foundation, compaction or hardening accelerator on the surface A surface-cured herbicide ("Geobest") formed by spraying an aqueous solution is described.

  In Non-Patent Documents 4 and 5, by blowing a chip material and adhesive that has been crushed thinned wood, house scrap, etc. in a spraying machine, to the slope or ground (slope, etc.) by the air of the compressor, It mainly describes surface hardening herbicides ("recycled wood chip sprayer") that prevent slope erosion and vegetation overgrowth. The construction method is a construction method equivalent to mortar spraying (that is, cleaning, lath stretching, spraying). In this method, the chip material with a small amount of fine particles is made to have a contact layer with an adhesive and a chip layer that is tightened by air pressure to form a hardened layer of about 5 cm to 15 cm even on an inclined slope. Thickness is secured and weed growth is suppressed.

Non-Patent Document 6 and Patent Document 16 describe a surface-curing herbicide by CC soil mulching method. In the CC soil mulching method, first, CC soil mulch VUs are installed on the slope at regular intervals. Next, a mortar-like material (CC soil mortar) specially blended with CC bark, washing sand, cement, and an eluting agent is placed. CC bark is a mixture of Cedar and Cypress skins. Then, remove the CC soil multi-VU and plant ground cover such as pine bees at a planting density of 4 to 10 pieces / m ² , and surface hardened herbicides where the ground cover was planted at appropriate intervals. Form. CC soil multi-mortar plays a role in suppressing the germination growth of weeds during the growth of this ground cover. Further, CC soil mortar has flexibility, water permeability and water retention because a fibrous material called CC bark is mixed with mortar. And in 3-4 years, weathering is repeated while freezing and thawing from the surface, and the ground cover roots can enter in the process of the ground cover growing.

Non-Patent Document 8 and Patent Document 17 describe a method for preventing soil erosion and weed control associated with rainfall or the like by thinly spraying a slurry of light-burned magnesia-based soil hardener and paste on the ground surface. Yes.
Japanese Laid-Open Patent Publication No. 2000-73370 JP 2005-307518 A JP 2006-177122 A JP 9-154420 A JP-A-10-131193 Japanese Utility Model Publication No. 6-43022 Japanese Patent Laid-Open No. 11-6122 Utility Model Registration No. 3134088 JP 2005-218384 A JP 2004-82657 A JP 2004-183270 A JP 2002-54150 A JP 2002-186410 A JP 2005-154735 A Design Registration No. 1144161 JP 2004-187487 A JP 2004-166627 A JP 2004-154071 A Tetsuya Nakagawa, “New utilization of generated wood”, [online], November 18, 2003, Ministry of Land, Infrastructure, Transport and Tourism Technical Committee, [Search October 31, 2007], Internet, <URL : http://www.mlit.go.jp/chosahokoku/h15giken/program/jiyuu_ippan.htm> Yuji Koga, “Weed control measures using root stock chips”, [online], October 25, 2006, 50th Agricultural Civil Society of Tohoku Branch, [October 31, 2007 search] , Internet, <URL: http://www.green.go.jp/area/seibi-nou/touhoku/morioka/gakkai/pdf/2006koriyama.pdf> Takei Kogyo Co., Ltd., Matsuda Giken Kogyo Co., Ltd., “Promoting and utilizing new technologies in the civil engineering department of Ibaraki Prefecture A. Gazette Geobest Weed Protection”, [online], October 17, 2007, Civil Engineering Department, Ibaraki Prefecture HP, [October 31, 2007 search], Internet, <URL: http://www.pref.ibaraki.jp/bukyoku/doboku/01class/class03/07netis/B_seihin/B06025.pdf> Kiyomi Shirato, “Construction Case of Cut Slope Protection Using New Chips / Construction Method”, Forest Road, Forest Road Study Group, April 2002, Vol.39, No.1 (communication number 369), pp 18-22. Affin Techno, "Recycled Wood Chip Sprayer", [online], July 25, 2007, Affin Techno HP, Inc. [October 31, 2007 search], Internet, <URL: http: // www.shinwa-techno.co.jp/doc/chip/index.html> Tohoku Ryokushin Sogo Co., Ltd., “Towards an environment-friendly“ flower and green road landscape ”with reduced weeds, CC soil mulching method Ver1.7” [online], August 3, 2002, Tohoku Ryoku Co., Ltd. Susumu General HP, [October 31, 2007 search], Internet, <URL: http://www1.odn.ne.jp/ryokusin/cc_soil.pdf> Cement-based solidified soil examination committee, “Study final report on cement-based solidified soil (draft)”, [online], June 30, 2003, Ministry of Land, Infrastructure, Transport and Tourism, HP, October 31, 2007 Search], Internet, <URL: http://www.mlit.go.jp/tec/kankyou/kurom/pdf/hokoku.pdf> Shinsaku Fujimori, Takeshi Tanimoto, Yusuke Wakasugi, “Surface mulching technology with light-burned magnesia-based soil hardener”, [online], December 28, 2004, National Institute of Agricultural Sciences and Food Technology Office, Farmland Development Department, Paddy Field Research Laboratory, [October 31, 2007 search], Internet, <URL: http://nkk.naro.affrc.go.jp/library/publication/seika/seikajyoho/2002 /22/22.html> Ube Materials Co., Ltd., “Surface Surface Mulching Technology Using Lightly Burned Magnesia Soil Hardener”, [online], Ube Materials Co., Ltd. HP, [October 31, 2007 Search], Internet, <URL: http: //www.ubematerials.co.jp/cgi-bin/prod3.pl?00001> Yamaguchi Shimbun, “Seawater-related substances, spreading applications,“ For soil hardening ”and“ Water quality improvement ”,” July 20, 2007 (Friday) article, Minato Yamaguchi Godo Shimbun R100 Soil Method Study Group, “Ecoder Method”, [online], R100 Soil Method Study Group HP, [October 31, 2007 Search], Internet, <URL: http://www.r100-soil.net/ modules / tinyd0 / index.php? id = 18>

  Of the above-described conventional herbicides, the surface covering herbicides using a herbicidal sheet, a herbicidal panel, a herbicidal block and the like are currently most widely used. However, the herbicidal sheet is easily damaged, and there is a problem that grass and miscellaneous trees begin to grow from the damaged part and the range gradually expands. In addition, grass protection blocks and panels are often bred after grass and miscellaneous trees begin to grow from the gaps between the blocks and panels. In addition, because the shapes of blocks and panels are standardized, it is difficult to fill them with a shape that is flexibly adapted to the shape of the slope. There is a problem of lacking.

  On the other hand, in the case of a surface-cured herbicide, since the coagulant is sprayed on the slope to be solidified, the problem that occurs in the surface-coated herbicide as described above does not occur. From the aspect of workability, surface hardening herbicides are excellent as slope weeders.

  However, among the conventional surface-curing herbicides, those using cement or a cement-based curing agent (hereinafter referred to as “cement-based curing agent”) (Patent Document 12, Patent Document 13, Non-Patent Document 2, Non-patent) With respect to Document 6 and Patent Document 16), there is a problem that waste is generated because the hardened cement cannot be reused. For example, when weeding a temporary road, if a cement-based hardener is placed on the surface of the road slope of the temporary road, the hardened cement used as the hardener when the temporary road is demolished is discarded The waste treatment is necessary. Further, the cement-based hardener contains hexavalent chromium, and when it is reused, it is necessary to carefully investigate and examine the elution problem of hexavalent chromium (see Non-Patent Document 7).

  Cement-based hardeners have the property of shrinking when dried. Therefore, when a cement-type hardener mixed with natural soil is sprayed on the slope and dried, a large number of minute gaps are generated due to drying shrinkage of the cement portion, and weathering is promoted by the gaps. Therefore, in order to maintain low weather resistance and the herbicidal effect for a long period of time, it is necessary to increase the amount of cement-based curing agent mixed with natural soil or increase the thickness of the hardened layer. There is a problem that a curing agent is required.

  In addition, the surface hardening herbicide may be used for protection of the shore of the dam lake in addition to the purpose of grass protection. The water level of the dam lake varies greatly depending on the season due to flood control and various water supply, and it is often submerged and exposed, so strip-shaped bare land often appears on the shore of the dam lake. The lake slope that has become bare in this way is unstable and easily collapses, and there is a problem that the sediment generated by the collapse accumulates on the dam lake and the dam capacity decreases. Therefore, the surface of the lake shore slope is hardened and stabilized by applying a surface hardening herbicide to the lake shore slope of the dam lake. At this time, when cement or cement-based hardener is used as the hardener, water penetrates into many voids generated in the hardened cement, and the calcium compound in the hydrated cement forms calcium carbonate by the penetrating water little by little. Dissolve and dissolve in dam lake water. Therefore, when the concentration of calcium carbonate in dam lake water becomes high, various problems such as water alkalizing and clogging due to calcium carbonate adhering to the water conduit occur.

  On the other hand, in the geobest construction described in Non-Patent Document 3 and Patent Document 14, magnesium oxide is used instead of the cement-based curing agent. Magnesium oxide has the property of expanding during curing, contrary to cement-based curing agents. Therefore, weathering is less likely to occur than cement-based curing agents.

  However, a hardener for soil containing magnesium oxide and a different metal salt tends to disintegrate when hardened unless compacted. Therefore, in the geobest construction, after the soil hardening agent is uniformly laid on the foundation, it is necessary to compact. In general, compaction is performed by rolling with a heavy machine such as a vibration compactor, vibration roller, nutation roller, or power shovel, or by manual compaction using a hand or the like. Therefore, although it is easy to apply to flat land, there is a problem that compaction work is difficult on a slope such as a slope, and the work labor is large.

  Moreover, the magnesium oxide actually used conventionally is manufactured from magnesium ore produced in northeastern China and the like. Magnesium oxide produced from magnesium ore is low in purity and contains many impurities. For this reason, it is difficult to cure as compared with a high purity one, and it is necessary to use a relatively large amount of a curing agent. Impurities may also contain harmful substances such as arsenic, which is difficult to reuse from the viewpoint of safety. When used for herbicides such as temporary roads as described above, roads are demolished. Later, waste is generated and waste disposal is required. In particular, when harmful impurities such as arsenic are contained, it is not preferable that the impurities are diffused in the environment. Therefore, there is a problem that processing is required to remove the impurities to a harmless level and the processing cost is increased. .

  In addition, in the case of the recycled woodchip sprayer described in Non-Patent Documents 4 and 5, because the house waste material is mixed, it cannot be recycled, and when used for herbicides such as temporary roads as described above In some cases, waste is generated after the road is demolished, and waste disposal is required. Moreover, although chip | tip material is couple | bonded with an adhesive agent and hardening strength is obtained, since the resin adhesive is used for this adhesive agent and there is no water permeability, permeation of water is prevented. Therefore, when applied to a slope, there is a problem that the hardened layer becomes an obstacle when discharging the water that springs up to the slope, and the drainage becomes worse. In addition, chip materials obtained by crushing thinned wood and house scrap are corroded and decomposed over time. And after decomposition | disassembly, a hole arises in the place where the chip | tip material existed. For this reason, weathering is promoted by the pores, and there is a problem that the period during which the herbicidal effect is obtained is relatively short.

  The methods for preventing soil erosion and controlling weeds described in Non-Patent Document 8 and Patent Document 17 are mainly intended to obtain a herbicidal effect in a field of cultivated land, and are applied to a slope. The weather resistance is insufficient.

  Therefore, the object of the present invention is that there is no landscape destruction in the natural landscape, it is possible to construct by spraying, it is excellent in weather resistance, can maintain the herbicidal effect over a long period of time, Ground that can reduce the amount used compared to the past, can be recycled after the slope is demolished when applied to the slope of a temporary road, etc., and can be applied without problems to stabilization of the shore of the dam lake An object of the present invention is to provide a covering and a ground covering method for constructing the covering.

  The first configuration of the present invention relating to the ground covering method includes a cotton-like bamboo short fiber formed by crushing bamboo shoots, a hardening agent containing magnesium oxide or magnesium hydroxide derived from seawater, and fine aggregate It has a root shield layer forming step that forms a root shield layer that blocks the passage of roots of vegetation by mixing the spray agent to be mixed with water and spraying it onto the construction ground with pressurized air without gaps. It is characterized by.

  According to this configuration, the spraying agent sprayed onto the construction ground is pressed by the spraying pressure by spraying the curing agent on the construction surface with pressurized air, and it is not necessary to separately press with a roller or a pressurizer. It will be in a tightened state. Therefore, it is possible to form a root shielding layer that is well tightened even in places where it is difficult to perform the pressing operation with a roller or a pressure device, as in the case of a slope. And since the hardness of a root shield layer is high, the roots and buds of vegetation cannot penetrate the root shield layer, and an excellent herbicidal effect is obtained.

  Magnesium oxide or magnesium hydroxide has a property of expanding when cured, contrary to a cement-based curing agent. Therefore, there is no problem of accelerated weathering due to the generation of microscopic voids caused by drying shrinkage, which is a problem with cement-based hardeners, and sufficient weather resistance of the root shield layer can be achieved by using a relatively small amount of magnesium oxide or magnesium hydroxide as a hardener. Sex can be obtained.

  Moreover, the bamboo short fiber functions as a filler (reinforcing agent) and a buffering material, and prevents cracks due to expansion when magnesium oxide or magnesium hydroxide is cured and expanded. In addition, the toughness of the root shielding layer is increased when the curing agent is cured. Bamboo short fibers are unlikely to be decomposed by bacteria unlike wood chips, and exist without being corroded for a long period of time when solidified by a curing agent, and do not cause pores due to corrosion. Therefore, the weather resistance of the root shielding layer is improved, and the herbicidal hardening can be maintained over a long period of time.

  In addition, bamboo short fibers are crushed in the longitudinal structure of fiber cells, and easily absorb water into the fiber cells by capillary action. Therefore, since it is excellent in water retention and water permeability, rainwater and spring water can be absorbed and the root shield layer can be kept moist for a long time. Therefore, it helps the ground cover to grow on the surface of the root shield layer and prevents the temperature of the surface of the root shield layer from rising. Accordingly, the temperature of the slope surface can be kept lower than when cured with a cement-based curing agent. In addition, since the root shield layer has good water permeability, the groundwater that is spilled on the slope oozes to the surface through the root shield layer, so that the slope can be prevented from being weakened by the groundwater.

  Further, by using bamboo short fibers instead of bamboo chips, it is possible to prevent the spraying material from being clogged in the spraying hose when the spraying agent is sprayed onto the construction ground. That is, the bamboo basket fibers of the bamboo basket are high in strength, and in the case of a normal bamboo chip obtained by crushing bamboo, many elastic long fiber fragments are mixed. Such long pieces are easily clogged in the spray hose and cause frequent interruption of the spraying operation. On the other hand, the bamboo short fiber used in the present invention is a cotton-like extremely finely crushed bamboo fiber, and since it is soft, it does not clog the hose for spraying. Therefore, the spraying operation can be performed smoothly.

  Moreover, no harmful impurities are contained in the curing agent by using magnesium oxide or magnesium hydroxide derived from seawater as the curing agent. Magnesium oxide or magnesium hydroxide is also a plant fertilizer component. Therefore, even if the waste material which destroyed the shielding layer by tearing down the construction ground is generated, the generated waste material can be recycled as fertilizer as it is, so that no waste is generated.

  Moreover, since magnesium oxide and magnesium hydroxide are hardly soluble in water, there is little dissolution deterioration by water of the root shielding layer. Therefore, the ground covering method of the present invention can be used for the purpose of stabilizing the striped bare land on the shore of the dam lake.

  Here, the “bamboo shoot material” refers to a material obtained by cutting out a bamboo shoot or underground stem portion of a plant of the bamboo family (or Gramineae bamboo subfamily). The “bamboo short fiber” refers to a cotton-like fibrous material obtained by tearing and crushing bamboo shoots and shearing, whereby a longitudinal structure of fiber cells is crushed. "Seawater-derived magnesium oxide or magnesium hydroxide" refers to magnesium hydroxide isolated from seawater using slaked lime, or magnesium oxide obtained by firing it at a high temperature. As the “fine aggregate”, natural earth-colored aggregates such as natural soil, masa soil, black soil, shirasu and red jade soil are used.

  The thickness of the “root shielding layer” is not particularly limited, but in order to obtain a sufficient herbicidal effect and save the spray material as much as possible, it is preferably about 3 to 10 cm, more preferably about 4 to 6 cm. Good.

  In the second configuration of the present invention related to the ground covering method, in the first configuration, seeds of the introduced plant to be introduced into the construction ground are mixed with the surface of the root shielding layer formed in the previous root shielding layer forming step. It has the surface base layer formation process which forms a surface base layer by spraying a vegetation base material, It is characterized by the above-mentioned.

  According to this configuration, since the root intrusion of the plant is prevented by the root shielding layer, the plant can root only on the surface base layer. Therefore, if the surface base layer is configured to be extremely thin, the growth of roots (deep roots) that extend deep into the soil is prevented, and only the roots (shallow roots) that spread in the shallow layer grow on the surface base layer. Thereby, the overgrowth of deep-rooted plants is suppressed (if the surrounding plants temporarily invade, it declines), and only shallow-rooted plants such as ground cover plants grow. In addition, since the root shielding layer contains bamboo short fibers, it has excellent water retention, and an effect of suppressing excessive drying of the surface base layer can be obtained. Moreover, by covering the surface base layer with a shallow-rooted plant, the humidity of the ground is maintained, temperature rise is prevented, and the landscape is also beautiful.

  Here, the thickness of the “surface base layer” is not particularly limited, but it is necessary to reduce the thickness in order to obtain a good herbicidal effect. By setting the surface base layer as thin as possible so that only introduced plants that are resistant to drying can grow, even if weeds temporarily invade from the surrounding area, they will decline without spreading and only the introduced plants remain. is there. Specifically, when the thickness of the surface base layer is about 10 to 15 mm, a good herbicidal effect can be obtained.

  The “introduced plant” is not particularly limited, but it needs to be a plant that can grow even in a thin surface base layer such as a ground cover plant. As such a plant, for example, a turfgrass, a plant of the genus Sedum (Dipteraaceae), a related species thereof, or a moss plant (Centai) can be used. This is because plants of the genus Sedum and moss can grow in a very thin soil layer and are suitable for use as a weed countermeasure.

  Specifically, Sedum genus or its related species include Sedum lineare, Sedum spurium, Sedum morganianum, Sedum burrito (= S. Morganianum burrito), Malva Sedum makinoi, Sedum mexicanum, Sedum hispanicum, Sedum rubrotinctum, Aurora (Sedum rubrotinctum 'Aurora'), Sedum aizoon var.spibumum s. ), Meigetsu (Sedum adolphii), Atsababenkei (Sedum pachyphyllum), Aedesia (Hylotelephium spectabile), Hidotelephium cauticolum, Hoseruyum (Hylotelephium sieboldii), Tunarenge (topenlums)・ Paraguayense (Graptopetalum paraguayensis 'Bronz'), Takitsu (Graptopetalum bellum), etc. can be used. In addition, as moss plants, snails, pokeweeds, high moss, cedar moss and the like can be used.

  According to a third configuration of the present invention relating to the ground covering method, in the first configuration, a surface base layer is formed by spraying a vegetation base material on the surface of the root shielding layer formed in the root shielding layer forming step. A surface base layer forming step, and a seedling step of spraying, seeding or manually placing seedlings of ground cover plants to be introduced into the construction ground or shoots or moss seeds on the surface of the surface base layer. It is characterized by that.

  In order to suppress weed intrusion from the periphery, the surface base layer is generally thin (usually about 10 to 15 mm), so seedlings or shoots of ground cover plants or moss seed moss introduced to the construction ground Cannot be planted (planted). Therefore, these seedlings and the like are introduced onto the surface of the surface base layer by spraying, sowing seedlings or by hand placement. When two to three weeks have passed, it will naturally adapt to the surface base layer due to rain, and the roots of the introduced plant will settle on the surface base layer or root within the surface base layer. In this way, by introducing the seedlings of the introduced plant by spraying, sowing seedling or hand placement, the work on the slope becomes easy and the introduction work can be performed efficiently.

  Here, as the “ground cover plant”, a shallow-root plant or moss resistant to drying is used. For example, the above-mentioned turfgrass, plants of the genus Sedum (Apiaceae) or related species thereof, moss plants (centiates), and the like. “Seedling” refers to a young plant with a root attached. “Shoot” (shoots) refers to a part of a stem with leaves cut out from a branch trunk.

The 4th composition of the present invention concerning the ground covering construction method has a tree planting process in which a tree seedling for planting the construction ground in the construction of any one of the above 1 to 3 is planted on the construction ground,
In the root shielding layer forming step,
The root shielding layer is formed by mixing the spraying agent with water and spraying the ground with compressed air to solidify the construction ground on which the trees are planted.

  According to this configuration, the construction ground can be greened by the target tree, and the ground between the trees is prevented by the root shielding layer. Therefore, weeds and ivy can be prevented from growing between the seedlings of the woven tree and the sunlight of the tree can be prevented, and only the selected tree can be grown in good condition. In addition, labor for maintenance such as weeding is reduced.

  According to the first configuration of the present invention relating to the ground covering method, the surface layer is formed of a cotton-like bamboo short fiber formed by crushing bamboo shoots, a hardening agent containing magnesium oxide or magnesium hydroxide derived from seawater, and fine bone A spraying agent containing a material is mixed with water, and a root shielding layer is formed by spraying the construction ground with pressurized air without any gaps.

  According to a second configuration of the present invention relating to the ground covering method, in the first configuration, a surface base is formed by spraying a vegetation base material mixed with seeds of an introduced plant to be introduced into the construction ground onto the surface of the root shielding layer. A layer is formed.

  According to a third configuration of the present invention relating to the ground covering method, in the first configuration, a surface base layer is formed by spraying a vegetation base on the surface of the root shielding layer, and the surface base layer is formed on the surface of the surface base layer. A seedling or shoot of a ground cover plant or moss seed moss to be introduced to the construction ground is introduced by spraying, sowing or hand placement.

According to a fourth configuration of the present invention related to the ground covering method, in any one of the first to third configurations, a tree seedling is planted on the construction ground on which the root shielding layer is formed,
The root shielding layer is formed by mixing the spraying agent with water on the construction ground on which the tree is planted and spraying it with compressed air to solidify it.

  As described above, according to the present invention, by using a soil-colored aggregate as an aggregate for a spraying material, the ground covering work can be easily integrated into a natural landscape, and the landscape is destroyed by the laying of the ground covering work. Can be prevented. In addition, the use of cotton-like bamboo short fibers made by crushing bamboo basket material instead of bamboo chips prevents bamboo from clogging in the spray hose and causes the ground covering to be constructed by spraying. It becomes possible. In addition, by using bamboo short fibers instead of wood chips, they can be maintained without being corroded over a long period of time, and the herbicidal and water retaining effects can be maintained over a long period of time. Further, by using a curing agent containing magnesium oxide or magnesium hydroxide derived from seawater as the curing agent, the weather resistance is superior to that of the cement-based curing agent, and the herbicidal effect can be maintained over a long period of time. Moreover, since magnesium oxide or magnesium hydroxide derived from seawater has a higher purity than that derived from minerals, it is easy to be cured, and the amount of the curing agent used can be suppressed as compared with the conventional one. In addition, since no harmful substances are contained as impurities, and magnesium oxide and magnesium hydroxide are also fertilizers, when they are applied to the slopes of temporary roads, they can be recycled after the slopes are demolished. In addition, magnesium oxide and magnesium hydroxide are poorly soluble in water and do not dissolve into water like cement-based hardeners and do not alkalinize water, so they can be applied without problems to stabilize the shores of dam lakes. Is possible.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In the ground covering work of the present embodiment, cotton-like bamboo short fibers, a curing agent, and fine aggregate described below are used as the spraying agent.

[1] Manufacturing method of spray material and its characteristics Hereinafter, the manufacturing method of each material and its characteristics will be described.

(1) Cotton-like bamboo short fiber The bamboo short fiber of a present Example is manufactured by crushing bamboo basket material and making it cotton-like. FIG. 1 shows a bamboo crushing apparatus. Fig.1 (a) is principal part sectional drawing of a bamboo crushing apparatus, FIG.1 (b) is the arrow sectional view seen from the AA line in Fig.1 (a). The bamboo crushing device is the same as that described in Patent Document 18.

  In the crushing device 1, a hopper 3 is attached to the upper surface of a hollow cylinder 2, and the hopper 3 communicates with an in-cylinder space 4 of the cylinder 2. The cylinder 2 is a cylindrical body that accommodates the screw conveyor 5 therein, the tip end portion is closed with a porous end plate 6, and the base end portion (the end portion on the side where the hopper 3 is attached) is the rear end. The end plate 7 is closed. The screw conveyor 5 has a rotating shaft in common with the center line c of the cylinder 2 and is rotatably supported between the bearing hole 9 a of the perforated end plate 6 and the bearing hole 9 b of the rear end plate 7. The screw conveyor 5 is provided with a spiral helix blade 8 around it, and the helix blade 8 has its tip in contact with the inner wall of the cylinder 2 and its helix pitch t gradually decreases from the base end side toward the tip end side. is doing. In addition, a large number of small through holes 10 are provided through the porous end plate 6. Further, a rotary blade 11 is provided coaxially with the screw conveyor 5 inside the cylinder 2 of the perforated end plate 6, and the rotary blade 11 rotates together with the screw conveyor 5. The rotary blade 11 is composed of two propeller-shaped blades, and the back surface thereof is in close contact with the porous end plate 6 and slides on the inner surface of the cylinder 2 of the porous end plate 6.

  The bamboo chip material or the bamboo chip material T obtained by crushing the bamboo basket material is put into the in-cylinder space 4 of the screw conveyor 5 from the hopper 3. The thrown bamboo material T is pushed and moved toward the tip by the rotation of the spiral blade 8 accompanying the rotation of the screw conveyor 5. The screw conveyor 5 has a helical pitch t that becomes narrower toward the tip, so that the bamboo chip material T is compressed and twisted by the rod that moves in the in-cylinder space 4 in the cylinder 2. When the bamboo chip material T reaches the porous end plate 6, the bamboo chip material T is pushed out of the cylinder 2 from a large number of small through holes 10 drilled in the porous end plate 6 by internal pressure. At this time, it is sheared to an appropriate length by the rotary blade 11 at the same time.

  In this way, the bamboo basket material extruded from the small through holes 10 of the perforated end plate 6 is sheared together with tearing and crushing into a short fiber cotton shape. This product is called “bamboo short fiber”. Bamboo short fibers have a longitudinal structure of fiber cells crushed to release both ends of the tissue and absorb water into the tissue by capillary action. Therefore, normal bamboo chips float when placed in water, but these bamboo short fibers are characterized by absorbing water and settling when placed in water.

(2) Hardener The hardener used in the present embodiment is one containing magnesium oxide or magnesium hydroxide derived from seawater. "Seawater-derived magnesium oxide or magnesium hydroxide" refers to magnesium hydroxide isolated from seawater using slaked lime, or magnesium oxide obtained by firing it at a high temperature. That is, when slaked lime is added to seawater, calcium is eluted by a reaction such as the following formula, and magnesium in the seawater is precipitated as magnesium hydroxide.

  When the magnesium hydroxide thus obtained is baked at a high temperature, a magnesia clinker is formed. What was crushed into powder is used as a curing agent. As such a curing agent, for example, a low alkaline soil curing agent manufactured by Ube Materials Co., Ltd. (trade name “Mug Natural (pavement expert / herbicide expert)”, CAS No. 1309-48- 4) can be used (see Non-Patent Document 9).

Seawater-derived magnesium oxide or magnesium hydroxide is characterized by extremely few impurities compared to those produced from magnesium ore. Further, since it does not contain harmful impurities such as arsenic, it can be reused as fertilizer. In particular, the low alkaline soil hardener (trade name “Mug Natural (pavement expert / herbicide expert)”) manufactured by Ube Materials Co., Ltd. is registered as a fertilizer based on Article 7 of the Fertilizer Control Law (Registration No. No. 47784). If it is used as a curing agent, it can be recycled as a fertilizer.
Table 1 shows the chemical composition of the curing agent used in this example. The physical properties of the curing agent used in this example were an apparent specific gravity of 0.7 and an average particle diameter of 3 μm.

(3) Fine aggregate As the fine aggregate, natural earth-colored aggregates such as natural soil, masa soil, black soil, shirasu and red jade soil are used. This is to avoid damaging the surrounding landscape.

(4) Mixing ratio of spraying material The mixing ratio of each composition of spraying material (short bamboo fiber, hardener, fine aggregate) must be adjusted as appropriate depending on the soil quality of the fine aggregate to be added. In the example, as an example, the blending ratio of bamboo short fiber, hardener, and fine aggregate is as follows.

  Here, as bamboo short fibers, bamboo cocoon fibers of Somune bamboo were used. As the curing agent, the above-mentioned low alkaline soil curing agent manufactured by Ube Materials Co., Ltd. is used, and its components are as shown in (Table 1). As fine aggregate, Masa soil was used.

[2] Slope construction method Next, the ground covering method according to the present embodiment will be described. Here, as an example, while planting seedlings of native tree species on the slope of the embankment road and planting them, we will lay a grass barrier to protect the grass around the stock of these seedlings.

(1) Leveling process First, the ground removal and weeding of the ground for construction of the ground cover are performed, and after weed roots are removed as much as possible, the leveling is performed. FIG. 2 shows a typical embankment slope 20 that has been leveled. The embankment slope 20 is composed of a block product slope 21, a step (inu run) 22, an upper embankment slope 23, a road shoulder 24, and a road floor 25 from the bottom to the top. The block product slope 21 is formed by stacking stacked blocks. The lowermost part of the block product slope 21 is referred to as a heel 26. A horizontal step 22 is formed on the upper end side of the block product slope 21, followed by an upper embankment slope 23. The upper bank slope 23 is formed by pressing natural soil. The uppermost part of the upper embankment slope 23 is called a shoulder 27. Following the shoulder 27, a horizontal road shoulder 24 and a road floor 25 are formed. A guard rail 28 is installed on the road shoulder 24.

(2) Tree-planting process Next, the shrub sapling seedling 29 of a local species tree is planted at a predetermined interval from the leveled step 22 to the upper embankment slope 23. In FIG. 3, the cross-sectional schematic diagram of the planted embankment slope is shown. The native species tree is a tree that grows naturally in the mountain area around the construction site, but it is preferable to select an evergreen shrub tree from the viewpoint of always greening. Further, from the viewpoint of work efficiency, the height of the shrub shoots 29 is preferably about 40 to 50 cm. Although the planting density of the shrub shoots 29 needs to be determined depending on the tree species, it is generally set to about 5 / m ² .

(3) Bagging process Next, bagging is performed on each planted seedling 29. In FIG. 4, the state hung on the shrub seedling 29 of the embankment slope 20 is shown. Each shrub shoot seedling 29 is covered with an air-permeable bag 30 on the leaf stem portion and tied with a tape or string so that the bag 30 does not come off. Here, the stock of the shrub bud seedling 29 is set so that the main trunk is exposed.

(4) Spraying process Next, the above-mentioned spraying material 31 is sprayed from the upper embankment slope 23 to the small steps 22. In FIG. 5, the state which is spraying the spraying material 31 on the embankment slope 20 is shown. When performing the spraying work, a temporary work fence 32 is temporarily installed on the upper shoulder 24 of the upper embankment slope 23, and the worker 33 is in a state of being bound by the temporary work fence 32 and the hanging strap 34 for safety. Do work.

  In the spraying operation, the spraying material 31 is pressure-fed by the compressor (not shown) through the spraying hose 35, and at the same time, the water hose 37 is used to supply water to the tip of the spraying hose 35. The spray material 31 and water are mixed in the vicinity of the tip of the spray hose 35, and the mixture of the water and the spray material 31 is sprayed from the spray nozzle 36 connected to the tip of the spray hose 35 and struck against the construction ground. By this striking pressure, the spray material 31 is pressed against the surface of the construction ground, and a root shielding layer 38 is formed on the surface of the construction ground. The thickness of the root shielding layer 38 may be determined as appropriate, but is usually about 5 cm.

  As described above, the spray material 31 includes natural soil aggregates such as natural soil, masa soil, black soil, shirasu, and red jade soil as fine aggregates. It becomes a color and does not destroy the landscape.

  Magnesium oxide contained in the spray material 31 reacts with water to become gel-like magnesium hydroxide. Further, magnesium hydroxide reacts with phosphoric acid in the soil and carbon dioxide in the air to become magnesium phosphate and basic magnesium carbonate, increasing the strength. As a result, the root shielding layer 38 is cured, and a herbicidal effect is obtained that blocks passage of buds and roots of plants and plants.

  FIG. 6 shows debris of the cured root shield layer 38. The root shielding layer 38 has a light brown color as a whole, and no fuzz of bamboo fibers is observed as in the case of mixing bamboo chips.

  In this embodiment, since the spraying material 31 is sprayed after planting the shrub bud seedling 29, the construction ground is covered with the spraying material 31 up to the root of the shrub bud seedling 29. Therefore, since the gaps where weeds and ivy grow can be completely sealed, an excellent herbicidal effect can be obtained. In addition, since the leaf stems of the shrub bud seedling 29 are covered with the bag 30, the spray material 31 does not adhere to them, and the stress applied to the shrub shoot seedling 29 during construction is minimized.

(5) Bag removal step After the root shield layer 38 is cured, the bag body 30 covered with each shrub seedling 29 is removed. FIG. 6 is a schematic cross-sectional view of the ground covering according to the completed embodiment 1. The root shielding layer 38 covers a part of the steps 22 and the shoulder 24 and the entire upper embankment slope 23 and prevents weeds and ivy from being generated over a long period of time. In addition, on the upper embankment slope 23, a shrub shoot seedling 29 of a local species tree is planted, and as the shrub bud seedling 29 grows, the slope is greened by the local species tree. As long as the native tree grows sufficiently to the extent that it does not lose to weeds and ivy, the root shielding layer 38 prevents the sunlight from hitting the seedlings. Keeps good. Further, since the root shield layer 38 is excellent in water retention and water permeability, it absorbs and retains rainwater and prevents the roots of the shrub shoots 29 from drying. Therefore, the growth conditions of the shrub bud seedling 29 are kept good.

  When the local species tree grows sufficiently after a long period of time, the root shield layer 38 will gradually weather, but the weathered root shield layer 38 will become a fertilizer for the native species tree and maintain the growth of the native species tree. become.

[3] Water retention of spray material Finally, the results of a test of the water retention of the spray material 31 will be described.

  The blending ratio of the spray material 31 used in the test is as shown in (Table 2). The test was performed as follows (see FIG. 8).

(1) First, the spray material 31 was placed in a rectangular parallelepiped mold and cured and sun-dried to form a specimen having a volume of 10 cm ³ . For comparison, a water retaining mat having the same volume and shape was prepared. Here, a polyester fiber was used as a water retention mat.

(2) Next, the specimen and the water retention mat were weighed with an electronic balance. The specimen was 20.0 g, and the water retention mat was 2.0 g.

(3) Next, the specimen and the water retention mat were placed in a tray filled with water, and immersed in water until saturated. During this time, after 1 minute, after 5 minutes, and after 10 minutes, the mass was measured with an electronic balance.

(4) Next, the specimen and the water retaining mat were lifted from the water and left to stand in a well-ventilated shade to dry naturally. Then, 1 hour, 6 hours, 24 hours, 48 hours, 72 hours, and 96 hours after the start of natural drying, the mass was measured with an electronic balance.

  The results of the experiment as described above are shown in FIGS. FIG. 9 is a diagram illustrating the time change of the water absorption when the specimen and the water retention mat are immersed in water. FIG. 10 is a diagram illustrating a temporal change in the water retention amount when the specimen and the water retention mat are naturally dried.

  As a result of the experiment, the absolute water absorption amount of the specimen was about 1/4 as small as that of the water retaining mat, but the water retaining mat lost almost moisture due to natural drying in 48 hours, whereas the specimen had 24 It can be seen that after the time, moisture is retained for an extremely long time of 96 hours or more while retaining moisture of about 4% of its own weight. This is presumed to be because the bamboo short fibers contained in the spray material 31 retain moisture in the longitudinal tissue of the fiber cells.

  From the above, it was demonstrated that the spray material 31 has excellent water retention.

  In addition, although the example which applied the ground covering to the banking slope 20 of a road was shown in the present Example, the ground covering of a present Example is the grass-proofing method and method of general slopes other than a banking slope. It can be similarly applied as a surface protection work. For example, the present invention can also be applied to the case where the shore of the dam lake is hardened and stabilized. In that case, in the ground covering work of this example, the hardened root shielding layer exhibits a natural earth shade, so that the landscape of the dam lake is not destroyed. In addition, the root shielding layer uses magnesium oxide derived from seawater as a curing agent, and does not have the harmful effect of alkalizing water by dissolving in water like a cement-based curing agent. Is safe because it contains no harmful substances.

  FIG. 11: is a cross-sectional schematic diagram of the ground covering work based on Example 2 constructed on the embankment slope. The ground covering work of the present embodiment is the same as the ground covering work of the first embodiment except that planting of native species trees is omitted and the seeds of the introduced plant to be introduced to the construction ground are mixed on the surface of the root shielding layer 38. The surface base layer 39 is formed by spraying a base material. Other parts are the same as those in the first embodiment. In FIG. 11, the same parts as those in FIG.

  The surface base layer 39 is a mixture of a vegetation base material (custom soil) and seeds of an introduced plant to be introduced into the construction ground. As the vegetation base material, beet moss, chemical fertilizer, wood fiber, bamboo short fiber compost, earthworm manure compost, and caking material are used. The mixing ratio of these materials is appropriately adjusted according to the situation of the construction site. Bamboo short fiber compost is a greening base material in which 70 to 80 parts of bark compost is added to and mixed with 30 to 20 parts of cotton-like bamboo short fibers described in Example 1 (Non-patent Document 11, Patent) Reference 18). For example, the product name “Ecoder” manufactured by R100 soil construction research group can be used. The caking additive is a material having an effect of preventing the seeds and the base material from flowing out, and various products are sold, so that they can be appropriately selected and used. For example, the product name “Kuricoat C-710” manufactured by Kurita Kogyo Co., Ltd. can be used.

  The thickness of the surface base layer 39 is 10 to 15 mm. This thickness is determined by the surrounding environment, but basically, it is preferable to set the thickness to a limit that allows only Sedum genus (Apiaceae) to grow, which is extremely resistant to drying. This is because, by making the surface base layer 39 in such a thin layer, even if weeds temporarily invade from the periphery, the surface base layer 39 declines without spreading.

  FIG. 12: is a cross-sectional schematic diagram of the ground covering work based on Example 2 constructed on the embankment slope. The ground covering work of the present embodiment is basically the same as the ground covering work of the second embodiment, but the seed of the introduced plant is not mixed in the surface base layer 39 of the present embodiment. Instead, immediately after spraying the surface base layer 39, the seedling 40 of the ground cover plant or the moss seed moss to be introduced to the construction ground is seeded by hand sowing. In addition, when the slope is steep, sowing is impossible, so spraying or placing is done.

  Pot seedlings and shoots are used for the seedling 40 of the ground cover plant to be seeded. FIG. 13 shows an example of seedlings of ground cover plants or bryophytes introduced to construction ground. Fig. 13 (a) is a pot seedling of Mexican manengusa, which is a perennial plant belonging to the genus Sedum, and Fig. 13 (b) is a seed moss of Snagoke of the genus Pleurotus.

  When seedling or placing the pot seedlings, after removing the root pot from the pot, leave the root pot as it is without unnecessarily unraveling it. Since the surface base layer 39 is a thin layer, the seedling 40 is only placed on the surface of the surface base layer 39. The root pot soil (seedling soil) serves as a weight for preventing the seedling 40 from being blown by the wind. When the seedling 40 rolls down, a wire mesh may be laid on the surface of the surface base layer 39 as necessary. In this way, when the seedling 40 is placed on the surface of the surface base layer 39, the roots of the seedling 40 naturally become familiar with the surface base layer 39 due to rain after two to three weeks, and the root of the ground cover plant. Also settle.

Bamboo crushing device. It is a cross-sectional schematic diagram of the embankment slope which was leveled. It is a cross-sectional schematic diagram of the planted bank slope. It is a figure which shows the state hung on the shrub seedling of a banking slope. It is a figure which shows the state which is spraying a spraying material on a banking slope. It is a fragment of the cured root shield layer. It is a cross-sectional schematic diagram of the ground covering according to Example 1 constructed on the embankment slope. It is explanatory drawing of the water retention test of a spraying material. It is a figure showing the time change of the amount of water absorption when a test body and a water retention mat | matte are immersed in water. It is a figure showing the time change of the amount of water retention when a test body and a water retention mat | matte are naturally dried. It is a cross-sectional schematic diagram of the ground covering according to Example 2 constructed on the embankment slope. It is a cross-sectional schematic diagram of the ground covering according to Example 3 constructed on the embankment slope. It is an example of seedlings of ground cover plants or moss seeds to be introduced into the construction ground.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crusher 2 Cylinder 3 Hopper 4 In-cylinder space 5 Screw conveyor 6 Porous end plate 7 Rear end plate 8 Spiral blade 9a, 9b Bearing hole 10 Small through hole 11 Rotary blade T Bamboo chip material 20 Embankment slope 21 Block product slope 22 Dandan
23 Upper embankment slope 24 Road shoulder 25 Road floor 26 Leg bottom 27 Shoulder 28 Guard rail 29 Shrub seedling 30 Bag body 31 Spraying material 32 Construction temporary fence 33 Worker 34 Hanging string 35 Spray hose 36 Spray nozzle 37 Water hose 38 Root shielding layer 39 Surface base layer 40 Seedling

Claims (8)

  Cotton-like bamboo short fibers formed by crushing bamboo shoots, a hardener containing magnesium oxide or magnesium hydroxide derived from seawater, and a spray containing fine aggregate are mixed with water and applied to the construction ground. A ground covering method characterized by having a root shielding layer forming step of forming a root shielding layer that blocks passage of roots of vegetation by spraying with compressed air without gaps.   It has a surface base layer forming step of forming a surface base layer by spraying a vegetation base material mixed with seeds of introduced plants to be introduced into the construction ground onto the surface of the root shield layer formed in the previous root shield layer forming step. The ground covering method according to claim 1. A surface base layer forming step of forming a surface base layer by spraying a vegetation base material on the surface of the root shield layer formed in the root shield layer forming step;
Spraying seedlings or shoots of ground cover plants to be introduced into the construction ground or moss seed moss on the surface of the surface base layer, sowing or seeding, and sowing steps,
The ground covering method according to claim 1, comprising: It has a tree planting process to plant tree seedlings for greening the construction ground on the construction ground,
In the root shielding layer forming step,
4. The root shielding layer is formed by mixing the spraying agent with water and spraying the ground with compressed air to solidify the construction ground on which the trees are planted. The ground covering method described.   The surface layer is made by mixing cotton-like bamboo short fibers made by crushing bamboo shoots, hardener containing magnesium oxide or magnesium hydroxide derived from seawater, and spray containing fine aggregate with water. A ground covering layer characterized in that a root shield layer is formed by spraying the ground with pressurized air without any gaps.   6. The ground covering layer according to claim 5, wherein a surface base layer is formed by spraying a vegetation base material mixed with seeds of introduced plants to be introduced into the construction ground on the surface of the root shielding layer.   A surface base layer is formed by spraying a vegetation substrate on the surface of the root shielding layer, and seedlings of seedlings or shoots or moss to be introduced into the construction ground are sprayed on the surface of the surface base layer, 6. The ground covering work according to claim 5, wherein the ground covering work is introduced by sowing or by hand placement. On the construction ground where the root shielding layer is formed, tree seedlings are planted,
The said root-shielding layer is formed by mixing the spraying agent with water on the construction ground on which the tree is planted and spraying it with compressed air to solidify it. The ground covering work according to any one of the above.