JP4897507B2 - Ground improvement method - Google Patents

Description

  The present invention relates to a ground improvement method.

  The Ministry of Land, Infrastructure, Transport and Tourism has been taking various measures since 1999 to promote the recycling of construction waste. Conventionally, the recycling technology for felled wood is as follows: (1) A method in which chipped felled wood is kneaded with seeds, compost components, etc., sprayed onto slopes, etc., installed by spreading, and used as a vegetation base material , (2) Bundling with binding wires, etc., using as a frame, (3) Temporary placement in the construction site, composting to make valuable resources, (4) Chipping felled timber as pavement resources Various methods have been developed and applied, such as a method to be used, (5) a method in which crushed material of felled wood and earth and sand are mixed and used to reinforce a slope (for example, see Patent Document 1).

JP 2003-171936 A

  However, for example, the vegetation base material installed by the method (1) has a thickness of about 50 cm, and the wooden material pavement installed by the method (4) has a thickness of about 30 cm. In the methods (2) and (3), the use is limited to a limited area. Therefore, the methods (1) to (4) have not reached the point where a large amount of felled wood can be recycled.

In the method (5), the wood may decay after a long period of time, thereby losing the effect of increasing the strength of the ground or reducing the volume.
For these reasons, the existing technology has not been able to meet the social needs, and the recycling rate of wood-based waste materials is approximately 40% in 2002, which is almost flat.

  This invention is made | formed in view of such a problem, The place made into the objective is to provide the improvement method of the ground which can recycle | recycle the logging material discarded as industrial waste on a large scale.

The present invention for achieving the above-described object includes a step (a) of covering a small piece of wood waste material with a covering material, a step (b) of mixing the small piece and a ground material to obtain a mixed material, And a step (c) of installing the mixed material on the ground, and using the plurality of mixed materials having different mixing ratios of the small pieces in the step (c), of the plurality of mixed materials, The ground improvement method is characterized in that a mixture having a large mixing ratio is installed in a shallow portion and a mixture having a low mixing ratio in a deep portion .

  The coating material is a material with high water barrier properties such as a high viscosity cement paste, a high viscosity asphalt emulsion, and a chemical resin. The high-viscosity cement paste is obtained, for example, by blending blast furnace cement type B with special admixtures described as compounds (α) and (β) in JP-A No. 2004-175608. The high-viscosity cement paste is mixed with mortar used in general porous concrete. The highly viscous asphalt emulsion is composed of, for example, rubber-containing asphalt emulsion and bentonite. The high-viscosity asphalt emulsion is a ready-made asphalt emulsion and cement or water added thereto.

The mixing ratio of the small pieces with respect to the mixed material is desirably 30% or less by volume ratio. (Deleted) In the step (c), a plurality of mixed materials having different mixing ratios of small pieces are used in combination, and a mixed material having a large mixing rate of small pieces is installed in the shallow part and a small mixed material is installed in the deep part .

  In the step (c), for example, the mixed material is installed on the slope of the embankment formed using the embankment material that is the ground material alone. Or a mixed material is installed in the slope and upper surface of the embankment formed using the embankment material which is ground material alone. In the step (c), a mixed material having a large piece mixing ratio may be installed on the slope and the upper surface of the embankment formed using a mixed material having a small piece mixing ratio. In the step (c), the mixed material may be installed on the surface layer of the ground, and the embedding material that is the ground material alone may be installed on the upper surface of the mixed material.

  ADVANTAGE OF THE INVENTION According to this invention, the improvement method of the ground which can recycle | recycle the logging material discarded as industrial waste on a large scale can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment of the present invention, first, wood-based waste materials such as felled wood are chipped into small pieces having a length of about 10 to 100 mm. Next, the chip-shaped pieces are covered with a covering material. The type of coating material and the coating method will be described later. And the small material coat | covered with ground materials, such as soil, is mixed, a mixed material is obtained, and a mixed material is used as a banking material.

  FIG. 1 is a graph showing a stress-displacement curve of the embankment material, FIG. 2 is a graph showing the relationship between the embankment material and the shear strength, and FIG. 3 is a table showing strength constants of the embankment material. 1 to 3 show a large-scale single-side shear test at a constant strain rate Δγ = 1.0% / min by making specimens with widths, lengths, and heights of 300, 300, and 650 mm, respectively, using embankment materials. It is the result of having performed.

In the graph showing the stress-displacement curve of the embankment material shown in FIG. 1, the horizontal axis is the horizontal displacement (mm), and the vertical axis is the shear stress τ (kN / m ² ). The (a) figure of FIG. 1 shows the test result at the time of using the Ebi famous loam which does not mix a small piece as a filling material. The solid line 1, the stress-displacement relationship when the confining pressure σv = 50kN / ^{m 2,} the dashed line 3, the stress-displacement relationship when the confining pressure σv = 100kN / ^{m 2,} the broken line 5, confining pressure [sigma] v = 300 kN / in the case of m ² is a stress-displacement relationship.

FIG. 1 (b) shows the test results when using a shrimp-made loam with a volume ratio of 1: 9 as the embankment material. The solid line 7, the stress-displacement relationship when the confining pressure σv = 50kN / ^{m 2,} the broken line 9, the stress-displacement relationship when the confining pressure σv = 100kN / ^{m 2,} the dashed line 11, confining pressure [sigma] v = 300 kN / in the case of m ² is a stress-displacement relationship.

FIG. 1 (c) shows test results when using a shrimp-made loam with a volume ratio of 3: 7 as a filling material. The solid line 13, confining pressure [sigma] v = stress-displacement relationship when the 50 kN / ^{m 2,} the dashed line 15, the stress-displacement relationship when the confining pressure σv = 100kN / ^{m 2,} the dashed line 17, confining pressure [sigma] v = 300 kN / in the case of m ² is a stress-displacement relationship.

  As shown in FIG. 1, the mixed material in which small pieces such as felled material are mixed into the loam, which is the ground material, has higher toughness than the loam alone. In ROHM alone, the yield point of the material can be clearly seen as shown in FIG. 1 (a), but in the mixed material, as shown in FIG. 1 (b) and FIG. 1 (c). In addition, a clear yield point is not confirmed, and the shear strength increases as the displacement progresses.

In the graph showing the relationship between the embankment material and the shear strength shown in FIG. 2, the horizontal axis is the upper loading pressure σv (kN / m ² ), and the vertical axis is the shear stress τ (kN / m ² ). The solid line 19 shows the relationship between the shear strength and the restraint pressure of the Ebina-made loam that does not contain small pieces, and the broken line 21 shows the shear strength and the restraint pressure of the Ebina-made loam where the mixing ratio of the small pieces and the loam is 1: 9 by volume. The broken line 23 shows the relationship between the shear strength and the restraint pressure of the shrimp famous loam with the volume ratio of the small pieces and the loam of 2: 8, and the broken line 25 shows the mixing ratio of the small pieces and the loam. Is the relationship between the shear strength and the restraining pressure of Ebi famous loam with a volume ratio of 3: 7.

The table showing the strength constants of the embankment material shown in FIG. 3 is a test manufactured using an embankment material in which small pieces and loam are mixed so that the chip mixing rate 27 is 0%, 10%, 20%, and 30%, respectively. For the body, the adhesive strength c (kN / m ² ) 29 and the shear resistance angle φ (deg.) 31 are summarized.

As shown in FIG. 2, the strength of the mixed material in which small pieces such as felled wood are mixed in the loam, which is the ground material, is higher than that of the loam alone. Moreover, as shown in FIG. 3, the adhesive force c (kN / m ² ) 29 and the shear resistance angle φ (deg.) 31 are significantly increased. The adhesive strength c (kN / m ² ) 29 hardly changes when the chip mixing rate 27 of the test specimen is 10% or more. The shear resistance angle φ (deg.) 31 hardly changes when the chip mixing rate 27 of the test specimen is 20% or more.

  As shown in FIGS. 1 to 3, in a mixed material in which small pieces such as felled wood are mixed into a loam that is a ground material, the deformation performance (toughness) and shear strength of the material are increased as compared with a loam alone. However, when it is intended to permanently use a wood-based waste material as a civil engineering material, there is a concern that the wood-based waste material, which is an organic matter, is decomposed and the strength of the material is reduced or the volume is reduced.

  Rotting is caused by fungi that grow by decomposing and using wood (wood rotting fungi), and in order for the rotting fungi to grow, "water", "oxygen", and "temperature" suitable for growth are required. In other words, if one of these three conditions is missing, it can be said that the wood will not decay. Therefore, it can be estimated that the decay of wood is less likely to proceed than near the ground surface because the amount of oxygen supplied is reduced in the ground.

  However, depending on the ground conditions, the amount of water supply increases and the possibility of further decay is suggested. This problem can be solved by blocking the moisture supply by coating the piece of wood with a suitable material. It is conceivable to use (1) high viscosity asphalt emulsion, (2) high viscosity cement paste, high viscosity mortar, (3) chemical resin, etc. for coating.

  FIG. 4 is a graph showing the results of the decay acceleration test, and FIG. 5 is a table showing the results of the decay acceleration test. 4 and 5 show the results of decaying a test piece coated with a 20 mm × 20 mm × 10 mm piece of wood by the decay test method of JIS K 1571.

  FIG. 4 shows the carbon residual rate after 35 months with respect to the total carbon content of the initial 33 of the test specimen. FIG. 5 shows the initial 33 carbon content and the 35 carbon content after 3 months.

  The test specimens used for the test consisted of a high-viscosity cement 39 in which a small piece of wood was coated with a high-viscosity cement paste, a high-viscosity asphalt 41 in which a small piece was coated with a high-viscosity asphalt emulsion, a chemical resin 43 in which a small piece was coated with vinyl acetate, There are four types of normal chips 37 that are not coated.

  The high-viscosity cement paste is obtained, for example, by blending blast furnace cement type B with special admixtures described as compounds (α) and (β) in JP-A No. 2004-175608. The high-viscosity cement paste is mixed with mortar used in general porous concrete.

  The highly viscous asphalt emulsion is composed of, for example, rubber-containing asphalt emulsion and bentonite. The high-viscosity asphalt emulsion is a ready-made asphalt emulsion and cement or water added thereto.

  The reason for using high-viscosity materials such as high-viscosity cement paste and high-viscosity asphalt emulsion for coating is that normal viscous materials cannot ensure adhesion between the chip and the material, and sufficient coating performance cannot be expected. It is.

  As shown in FIG. 5, the total carbon content (%) at the initial stage 33 of the four types of test specimens is the same, but after 3 months, the total carbon content (%) at 35 is high viscosity cement 39, high viscosity. Both the asphalt 41 and the chemical resin 43 usually exceed the chip 37. As shown in FIG. 4, this phenomenon becomes clearer by showing the total carbon residual ratio (%). 4 and 5, it can be seen that when a wood-based piece is coated, the decay of the wood is slow and the decay of the wood can be suppressed.

  On the other hand, with asphalt emulsions and chemical resins, it is expected that the coating material will deteriorate due to UV rays, but the problem of UV deterioration of the coating material is caused by embedding the coated wooden pieces in the soil. can be solved.

  FIG. 6 is a graph showing the relationship between the embankment material and the shear strength, and FIG. 7 is a table showing the strength constant of the embankment material. 6 and 7, similarly to FIGS. 1 to 3, specimens having widths, lengths, and heights of 300, 300, and 650 mm, respectively, are manufactured using the embankment material, and a constant strain rate Δγ = 1. It is the result of conducting a large-scale single-sided shear test at 0% / min.

  The test specimens used in the tests in FIGS. 6 and 7 are a loam 45 using a shrimp-made loam that does not contain small pieces as a filling material, and a small piece and a loam that are not coated as a filling material in a volume ratio of 3: 7. Countermeasure chip 47 using a mixed material, a countermeasure type A chip 49 using a mixed material in which a small volume coated with a high-viscosity cement paste and a loam are mixed at a volume ratio of 3: 7 as a banking material, a banking material There are four types of countermeasure type B chip 51 using a mixed material obtained by mixing small pieces coated with a highly viscous asphalt emulsion and loam in a volume ratio of 3: 7.

In the graph showing the relationship between the fill material and the shear strength shown in FIG. 6, the horizontal axis is upper No圧σv (kN / m ^2), the vertical axis represents the shear strength τf (kN / m ^2). The solid line 53 indicates the relationship between the shear strength and the restraining pressure of the loam 45, the broken line 55 indicates the relationship between the shear strength and the restraining pressure of the countermeasureless tip 47, and the broken line 57 indicates the shear strength and the restraining pressure of the countermeasure-type B tip 51. The broken line 59 indicates the relationship between the shear strength of the countermeasure type A tip 49 and the restraining pressure.

The table showing the strength constants of the embankment material shown in FIG. 7 shows the adhesive strength c (kN / m ² ) for four types of specimens: ROHM 45, countermeasureless chip 47, countermeasure type A chip 49, and countermeasure type B chip 51. 61 and the shear resistance angle φ (deg.) 63 are summarized.

6 and 7, the test specimen of the countermeasure type A chip 49 has a shear strength τf, an adhesive force c (kN / m ² ) 61, and a shear resistance angle φ (deg) as compared with the test specimen of the non-measure chip 47. .) 63 rises, and it can be seen that the strength increasing effect of the embankment material is further enhanced by using the high-viscosity cement paste as a small coating material. Moreover, the strength reduction by decay is not so remarkable.

  FIG. 8 shows a cross-sectional view of the embankment 65. As described with reference to FIGS. 1, 2, and 6, the embankment material in which the small pieces of wood are added to the ground material increases the shear strength of the material, so that the high-strength embankment (steep slope, high embankment) Suitable for construction. In FIG. 8, the embankment material 71, which is a mixed material in which small pieces such as felling material are mixed with the ground material, is installed on the slope 73 of the portion formed by using the embankment material 69 that is the ground material alone on the ground 67. The embankment 65 is formed.

  In the embankment 65, by using a mixed material as the embankment material 71, effects such as an increase in shear resistance and prevention of surface erosion can be expected, which is effective for reducing the earth pressure acting on the retaining wall and reducing the starting moment during an earthquake. is there. Moreover, the unit volume weight of the embankment material 71 can be reduced and the embankment 65 can be reduced in weight by using the mixed material which injected | thrown-in the wood-type small piece.

In the embankment 65, by increasing the thickness of the embankment material 71, it is possible to recycle large pieces. In the preliminary test shown in FIG. 1 to FIG. 3, small pieces such as felled timber can be introduced up to 30% by volume ratio. For example, if the completed mold is 10,000 m ³ , the small piece of 3000 m ³ Can be input.

  FIG. 9 is a cross-sectional view of the embankment 75 and the embankment 85. As described with reference to FIGS. 3 and 7, the strength constant of the embankment material can be changed depending on the mixing rate of small pieces and the type of coating material. Utilizing this property, for example, a material with a relatively high mixing rate of small pieces is used as the embankment material in areas where high strength is required in the embankment (embankment surface layer, or areas that are considered weak in design). However, a high-strength embankment can be constructed by a method such as using a mixed material having a relatively low small piece mixing rate or a ground material alone as the embankment material in a place where this is not the case.

  FIG. 9A is a cross-sectional view of the embankment 75. In FIG. 9 (a), the embankment material 83, which is a mixed material in which small pieces such as felling material are mixed with the ground material on the surface 79 of the portion formed by using the embankment material 81 which is the sole material alone on the ground 77, is shown. And the embankment 75 is formed. Alternatively, the embankment material 83, which is a mixture having a smaller mixing rate than the embedding material 81, is applied to the surface 79 of the portion formed using the embedding material 81, which is a mixed material obtained by mixing small pieces such as felling material with the ground material Install and form fill 75.

  Usually, the soil material has a certain strength at a deep part where the restraining pressure is high, but only an adhesive force contributes to the strength at a shallow part where the restraining pressure is smaller than the deep part. Like the embankment 75, if the mixing rate of the small pieces to the embankment material 83 used for the shallow portion is larger than the mixing rate of the small pieces to the embankment material 81 used for the deep portion, the adhesive force of the material in the shallow portion is increased. Can do. As a result, the stability against surface slip can be maintained.

  FIG. 9B is a cross-sectional view of the embankment 85. In FIG. 9 (b), the embedding material 89, which is a mixed material obtained by mixing small pieces of cutting material and the like with the ground material, is installed on the surface layer of the ground 87 with a certain thickness, and the ground material alone is placed on the upper surface of the embankment material 89. The embankment material 91 is installed to form the embankment 85. Thereby, the slip of the part formed using the embankment material 91 can be prevented.

  In this embodiment, by using a mixed material in which small pieces such as felled wood are mixed with loam, which is the ground material, the deformation performance (toughness) of the embankment material is increased, so even if deformation occurs, it is very broken. Difficult banking can be constructed. Moreover, deterioration of a small piece can be prevented by coating the small piece with a high-viscosity cement paste, a high-viscosity asphalt emulsion, a chemical resin, or the like.

  As mentioned above, although preferred embodiment of the ground improvement method concerning this invention was described referring an accompanying drawing, this invention is not limited to this example. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, in FIGS. 8 and 9A, the example in which the mixed material is used to reinforce the embankment 65 and the embankment 75 is shown, but a mixed material may be used to reinforce the cut.

Graph showing stress-displacement curve of embankment material Graph showing the relationship between embankment material and shear strength Table showing strength constant of embankment material Graph showing the results of the decay acceleration test Table showing results of decay acceleration test Graph showing the relationship between embankment material and shear strength Table showing strength constant of embankment material Cross section of embankment 65 Cross section of embankment 75, embankment 85

Explanation of symbols

27 ... …… Chip mixing rate 29, 61 ……… Adhesive strength 31, 63 ……… Shear resistance angle

Claims (4)

A step (a) of covering a small piece of wooden waste material with a covering material;
A step (b) of mixing the small piece and the ground material to obtain a mixed material;
A step (c) of installing the mixed material on the ground;
Equipped with,
In the step (c), a plurality of the mixed materials having different mixing ratios of the small pieces are used, and among the plurality of mixed materials, those having a large mixing ratio of the small pieces are installed in a shallow portion, and those having a small mixing ratio are installed in a deep portion. A ground improvement method characterized by the above. 2. The ground according to claim 1, wherein in the step (c), a mixed material having a high mixing rate of small pieces is installed on a slope and an upper surface of the embankment formed using a mixing material having a low mixing rate of small pieces. Improved method. The ground improvement method according to claim 1 or 2, wherein the coating material is a high-viscosity cement paste, a high-viscosity asphalt emulsion, a chemical resin, or the like. The ground improvement method according to any one of claims 1 to 3, wherein a mixing ratio of the small pieces to the mixed material is 30% or less by volume ratio.

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