Construction method of water cut-off layer

Abstract

To provide a construction method allowing a water cut-off layer to be easily constructed while quality and sizes are kept steady.SOLUTION: A construction method of a water cut-off layer comprises steps of: constructing a water cut-off layer 1A through installation of a plurality of bentonite mixed soil blocks 10 formed in a block shape using bentonite mixed soil; arranging the almost rectangular parallelepiped bentonite mixed soil blocks 10 along a slope surface B1 in a stacking state; and placing a bentonite mixed soil block 10B formed in a wedge-like shape between a bentonite mixed soil block 10A placed on a bottom step and a placing surface A1 along a generally horizontal surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for constructing a water impermeable layer. [Background technology]

[0002] Conventionally, final disposal sites for general waste, industrial waste, etc. have been required to install surface or vertical water barriers as a measure to prevent contamination of public water bodies and groundwater by leachate from landfill sites.

[0003] For surface waterproofing works, the following three double waterproofing structures (1) to (3) are specified: (1) Placing clay on top of the permeable layer, then placing a waterproof sheet and a protective mat on top of that, and then placing protective soil; (2) Placing watertight asphalt concrete on top of the permeable layer, then placing a waterproof sheet and a protective mat on top of that, and then placing protective soil; (3) Placing a protective mat and permeable sheet on top of the permeable layer, then placing an intermediate protective layer made of a protective mat or sand on top of that, then placing a waterproof sheet and a protective mat on top of that, and then placing protective soil.

[0004] In recent years, there have been cases where bentonite mixed soil, which is expected to have a water-stopping effect due to its self-repairing properties, has been adopted instead of clayey soil (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-020161 Summary of the Invention [Problem to be solved by the invention]

[0006] However, because the soil and sand used as the base material for bentonite-mixed soil is generated on-site during the construction of the final disposal site, the soil's properties are not uniform, making it difficult to ensure uniformity in the bentonite-mixed soil after construction. Furthermore, because bentonite swells when it comes into contact with water, it is necessary to prevent infiltration by rainfall or groundwater springs when mixing the bentonite and the generated soil on-site and during construction. Even if waterproofing measures are taken, such as covering the area with waterproof sheets, it is difficult to respond to sudden weather changes. Another construction issue is the difficulty of using roller compaction on sloped surfaces.

[0007] Therefore, the present invention has been made in consideration of the above circumstances, and provides a method for constructing a water shielding layer that is easy to construct while stabilizing quality and dimensions. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention employs the following means. That is, in the method for constructing a water impermeable layer according to the present invention, a plurality of bentonite-mixed soil blocks formed into a block shape from bentonite-mixed soil are installed to construct a water impermeable layer.

[0009] In this method for constructing a water impermeable layer, the bentonite-mixed soil blocks can be manufactured in a factory, which allows for stable quality and dimensions. Furthermore, construction can be easily carried out on site, as the bentonite-mixed soil blocks only need to be installed.

[0010] Furthermore, in the method for constructing a water impermeable layer according to the present invention, a plurality of the bentonite-mixed soil blocks formed in a substantially rectangular parallelepiped shape may be piled up and installed along a slope, and a wedge-shaped bentonite-mixed soil block may be installed between the bentonite-mixed soil block installed at the bottom and an installation surface along a substantially horizontal plane.

[0011] In this method for constructing a water-impermeable layer, by installing bentonite-mixed soil blocks formed in a wedge shape, it is possible to prevent the multiple bentonite-mixed soil blocks from sliding downward, thereby constructing a stable water-impermeable layer.

[0012] Furthermore, in the method for constructing a water-impermeable layer according to the present invention, an excavation surface may be formed at a substantially right angle to the slope, and multiple bentonite-mixed soil blocks formed in a substantially rectangular parallelepiped shape may be stacked and installed from the excavation surface along the slope.

[0013] In the method for constructing a water-impermeable layer configured in this manner, by providing an excavation surface, it is possible to prevent the multiple bentonite-mixed soil blocks from sliding downward, thereby constructing a stable water-impermeable layer.

[0014] Furthermore, in the method for constructing a water impermeable layer according to the present invention, the bentonite-mixed soil blocks, which are formed in a substantially parallelogram shape in a cross section perpendicular to the installation surface along a substantially horizontal plane and the slope, may be stacked and installed along the slope.

[0015] In the method for constructing a water-blocking layer configured in this manner, the water-blocking layer can be easily constructed along the slope by placing bentonite-mixed soil blocks that are formed in an approximately parallelogram shape in a cross-sectional view perpendicular to the slope and the installation surface that is approximately horizontal. [Effects of the Invention]

[0016] According to the method for constructing a water shielding layer of the present invention, construction can be easily carried out while stabilizing quality and dimensions. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram showing a method for constructing a water shielding layer according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a schematic diagram showing a method for constructing a water shielding layer according to a second embodiment of the present invention. [Figure 3]FIG. 10 is a schematic diagram showing a method for constructing a water shielding layer according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram showing a method for constructing a water shielding layer according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] (First embodiment) A method for constructing a water shielding layer according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a method for constructing a water shielding layer according to a first embodiment of the present invention. As shown in Fig. 1, the method for constructing a water impermeable layer according to this embodiment is to install the water impermeable layer on an installation surface A1 formed above a water permeable layer at, for example, a final disposal site for municipal waste, industrial waste, etc. In the illustrated example, the installation surface A1 is formed along a substantially horizontal plane. Note that the installation surface A1 may be slightly inclined relative to the horizontal plane.

[0019] A plurality of bentonite-mixed soil blocks 10 are placed on the installation surface A1 to construct the water barrier layer 1. The bentonite-mixed soil blocks 10 are formed by mixing bentonite with gravel and sand and then compacting the mixture into a block shape. The bentonite-mixed soil blocks 10 are formed in a roughly rectangular parallelepiped shape. Adjacent bentonite-mixed soil blocks 10 are placed so that they are in contact with each other. The end faces 11 of the bentonite-mixed soil blocks 10 are roughly perpendicular to the installation surface A1. The shape of the bentonite-mixed soil blocks 10 can be set as appropriate.

[0020] In the construction method of the water-impermeable layer configured in this manner, the bentonite mixed soil blocks 10 can be manufactured in a factory, so that the quality and dimensions can be stabilized, and problems such as variations in quality that occur during on-site construction can be eliminated.

[0021] Furthermore, construction can be easily carried out on site because all that is required is to set up the bentonite mixed soil blocks 10. On-site work requires only the block placement device, which limits the number of construction machines required.

[0022] (Second embodiment) Next, a method for constructing a water shielding layer according to a second embodiment of the present invention will be described mainly with reference to Fig. 2. In the following description of the embodiment, the same or similar members and parts as those in the above-described embodiment will be designated by the same reference numerals, and their description will be omitted, and only configurations different from the embodiment will be described.

[0023] FIG. 2 is a schematic diagram showing a method for constructing a water shielding layer according to a second embodiment of the present invention. As shown in FIG. 2, the water-shielding layer 1A formed along a slope B1 inclined relative to the installation surface A1 has a plurality of bentonite-mixed soil blocks 10 and a wedge-shaped bentonite-mixed soil block 10 (referred to as a "wedge bentonite-mixed soil block 10B").

[0024] A plurality of bentonite-mixed soil blocks 10 are piled up and installed along the slope B1. The end faces 11 of the bentonite-mixed soil blocks 10, which are formed in a substantially rectangular parallelepiped shape, are substantially perpendicular to the slope B1.

[0025] The bentonite-mixed soil wedge block 10B is placed between the lowest bentonite-mixed soil block 10 (referred to as "bentonite-mixed soil block 10A") and the installation surface A1. The bentonite-mixed soil wedge block 10B has a substantially triangular shape in a cross section perpendicular to the installation surface A1 and the slope B1. By fitting the bentonite-mixed soil wedge block 10B between the bentonite-mixed soil block 10A and the installation surface A1, the multiple bentonite-mixed soil blocks 10 are prevented from sliding downward.

[0026] In the construction method of the water-impermeable layer configured in this manner, the bentonite mixed soil blocks 10 can be manufactured in a factory, so that the quality and dimensions can be stabilized, and problems such as variations in quality that occur during on-site construction can be eliminated.

[0027] Furthermore, since the bentonite mixed soil blocks 10 only need to be installed at the construction site, the water shielding layer 1A can be easily constructed along the slope B1. The only on-site work required is the block placement device, which limits the number of construction machines.

[0028] Furthermore, when constructing the water-shielding layer 1 along the slope B1, by installing the wedge bentonite-mixed soil block 10B, it is possible to prevent the multiple bentonite-mixed soil blocks 10 from sliding downward, thereby constructing a stable water-shielding layer 1.

[0029] (Third embodiment) Next, a method for constructing a water shielding layer according to a third embodiment of the present invention will be described mainly with reference to Fig. 3. In the following description of the embodiment, the same or similar members and parts as those in the above-described embodiment will be designated by the same reference numerals, and their description will be omitted, and only configurations different from the embodiment will be described.

[0030] FIG. 3 is a schematic diagram showing a method for constructing a water shielding layer according to a third embodiment of the present invention. As shown in FIG. 3, the water shielding layer 1B formed along the slope B1 has a plurality of bentonite mixed soil blocks 10.

[0031] An excavated surface A2 is formed on the installation surface A1. The excavated surface A2 is formed by digging down the installation surface A1. The excavated surface A2 is formed so as to be approximately perpendicular to the slope B1.

[0032] Multiple bentonite-mixed soil blocks 10 are piled up and installed from excavation surface A2 along slope B1. The lowest bentonite-mixed soil block 10A abuts excavation surface A2. The end face 11 of each bentonite-mixed soil block 10, which is formed in a roughly rectangular parallelepiped shape, is roughly perpendicular to slope B1. By fitting the bentonite-mixed soil block 10A into excavation surface A2, which slopes downward from installation surface A1, the multiple bentonite-mixed soil blocks 10 are prevented from sliding downward, and a stable water barrier layer 1 can be constructed.

[0033] In the construction method of the water-impermeable layer configured in this manner, the bentonite mixed soil blocks 10 can be manufactured in a factory, so that the quality and dimensions can be stabilized, and problems such as variations in quality that occur during on-site construction can be eliminated.

[0034] Furthermore, since the bentonite-mixed soil blocks 10 only need to be installed at the construction site, the water-blocking layer 1B can be easily constructed along the slope B1. The only on-site work required is the block placement device, which limits the number of construction machines.

[0035] Furthermore, even when constructing the waterproof layer 1B along the slope B1, by providing an excavation surface A2, it is possible to prevent the multiple bentonite mixed soil blocks 10 from sliding downward, thereby constructing a stable waterproof layer 1.

[0036] (Fourth embodiment) Next, a method for constructing a water shielding layer according to a fourth embodiment of the present invention will be described mainly with reference to Fig. 4. In the following description of the embodiment, the same or similar members and parts as those in the above-described embodiment will be designated by the same reference numerals, and their description will be omitted, and only configurations different from the embodiment will be described.

[0037] FIG. 4 is a schematic diagram showing a method for constructing a water shielding layer according to a fourth embodiment of the present invention. As shown in FIG. 4, the water shielding layer 1C formed along the slope B1 includes a plurality of bentonite mixed soil blocks 10C.

[0038] The bentonite-mixed soil block 10C is formed in a substantially parallelogram shape in a cross section perpendicular to the installation surface A1 and the slope B1. Multiple bentonite-mixed soil blocks 10C are stacked from the installation surface A1. The bentonite-mixed soil blocks 10C are stacked and installed so that adjacent bentonite-mixed soil blocks 10C abut against each other. The end faces 12 of the bentonite-mixed soil blocks 10C are aligned along a substantially horizontal plane. However, the end faces 12 of the bentonite-mixed soil blocks 10C may be slightly inclined relative to the substantially horizontal plane.

[0039] In the method for constructing a water-impermeable layer configured in this manner, the bentonite mixed soil block 10C can be manufactured in a factory, so that the quality and dimensions can be stabilized, and problems such as variations in quality that occur during on-site construction can be resolved.

[0040] Furthermore, since it is only necessary to install the bentonite mixed soil blocks 10C at the site, the water shielding layer 1C can be easily constructed along the slope B1. The on-site work requires only the block placement device, which limits the number of construction machines.

[0041] The shapes and combinations of the components shown in the above-described embodiment are merely examples, and various modifications can be made based on design requirements, etc., within the scope of the present invention.

[0042] The Sustainable Development Goals (SDGs) are 17 international goals adopted at the United Nations Summit in September 2015. The method for constructing a water-impermeable layer according to this embodiment can contribute to achieving one of the 17 SDGs, for example, goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation." [Explanation of symbols]

[0043] 1, 1A, 1B, 1C Water impermeable layer 10, 10A, 10B, 10C Bentonite mixed soil block A1 Installation surface A2 digging surface B1 Slope

Claims

1. A method for constructing a water-impermeable layer in which a plurality of bentonite-mixed soil blocks formed into block shapes from bentonite-mixed soil are installed to construct a water-impermeable layer.

2. A plurality of the bentonite mixed soil blocks formed into a substantially rectangular parallelepiped shape are piled up and installed along the slope, 2. The method for constructing a water impermeable layer according to claim 1, wherein the bentonite mixed soil block is formed in a wedge shape and placed between the bentonite mixed soil block placed at the lowest level and a placement surface that is substantially horizontal.

3. The excavation surface is formed at a right angle to the slope, 2. The method for constructing a water impermeable layer according to claim 1, wherein a plurality of the bentonite-mixed soil blocks formed into a substantially rectangular parallelepiped shape are piled up and installed from the excavation surface along the slope.

4. 2. The method for constructing a water impermeable layer according to claim 1, wherein the bentonite-mixed soil blocks are formed in a substantially parallelogram shape in a cross section perpendicular to the installation surface along a substantially horizontal plane and the slope, and are stacked and installed along the slope.

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