Sheet member and construction method

Abstract

To effectively suppress the adhesion of bentonite mixed soil to a rolling compaction wheel of a vibration roller when compacting the bentonite mixed soil.SOLUTION: A sheet member 20 for preventing bentonite-mixed soil BM from adhering to an outer peripheral surface of a rolling compaction wheel 15 having a circular cross section and provided in a vibrating roller 10, wherein the sheet member 20 is formed of a water-repellent resin material, has a plurality of fine grooves 21 on its surface that extend in a predetermined direction, and is attached to the outer peripheral surface of the rolling compaction wheel 15 so that a longitudinal direction of the fine grooves 21 and a circumferential direction of the rolling compaction wheel 15 are not orthogonal to each other.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a sheet member and a construction method, and in particular to a technique suitable for compacting an earthen water barrier layer made of bentonite-mixed soil. [Background technology]

[0002] For example, Patent Document 1 discloses a technology in which an anti-adhesion sheet made of rubber or vinyl resin is attached to the roller wheels of a vibrating roller to prevent soil and sand from adhering to the roller wheels during compaction work.

[0003] For example, Patent Document 2 discloses a technology in which a plurality of hemispherical protrusions are formed by embossing the surface of a resin sheet whose resin component is polytetrafluoroethylene (hereinafter, PTFE), and the resin sheet is attached to the surface of a hopper or bucket to prevent raw materials, snow, etc. from adhering to these surfaces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 48-53806 [Patent Document 2] Utility Model Registration No. 3224058 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, waste disposal sites constructed underground have a water-blocking layer between the site and the surrounding ground to prevent rainwater and other substances that have permeated the waste layer from flowing into the surrounding ground and causing soil contamination. The water-blocking layer is made of bentonite-mixed soil, which is made by mixing bentonite with the base soil and sand. Bentonite-mixed soil can achieve high water-blocking performance by compacting it with a vibrating roller.

[0006] This type of bentonite-mixed soil is highly viscous and has very strong adhesive properties. For this reason, if the water content of the bentonite-mixed soil is high, or if the temperature at the work site fluctuates greatly throughout the day and condensation is likely to form on the rollers of the vibratory roller as the temperature drops, the bentonite-mixed soil will adhere to the surface of the rollers during compaction. If the bentonite-mixed soil adheres to the surface of the rollers, depending on the amount of adhesion, it may roughen the compacted surface.

[0007] If the compacted surface of the waterproof layer becomes rough, there is a concern that it will not meet the quality standards for unevenness of the finished surface. There is also a concern that the thickness of the waterproof layer may fall below the design value due to the unevenness, making it impossible to guarantee performance and quality. In such cases, shaping or additional compaction work may be required, which can affect productivity.

[0008] In the technology described in Patent Document 1, the surface of the anti-adhesion sheet is smooth and flat, without any processing. Therefore, when compacting highly adhesive bentonite-mixed soil, the bentonite-mixed soil may adhere to the surface of the anti-adhesion sheet, which may result in the sheet not being effective. In the technology described in Patent Document 2, multiple protrusions are formed on the surface of the resin sheet. However, because the protrusions are formed by embossing, when applied to compacting bentonite-mixed soil, the diameter of the protrusions is larger than the soil particle diameter of the bentonite-mixed soil, so there is a possibility that the anti-adhesion effect may not be fully exerted.

[0009] The technology disclosed herein has been made in consideration of the above circumstances, and aims to effectively prevent the compacted soil from adhering to the roller wheels. [Means for solving the problem]

[0010] The sheet member (20) of the present disclosure is A sheet member (20) that suppresses adhesion of soil to be compacted to the outer peripheral surface of a rolling wheel (15) having a circular cross section that is provided on a rolling machine (10), The sheet member (20) is made of a water-repellent resin material, and has a plurality of fine grooves (21) extending in a predetermined direction on its surface. The sheet member (20) is attached to the outer circumferential surface of the roller wheel (15) so that the longitudinal direction of the fine grooves (21) and the circumferential direction of the roller wheel (15) are not perpendicular to each other. It is characterized by:

[0011] In another embodiment of the sheet member (20) of the present disclosure, The plurality of fine grooves (21) are formed by hairline processing. It is preferable.

[0012] In another embodiment of the sheet member (20) of the present disclosure, The sheet member (20) is attached to the outer circumferential surface of the roller (15) so that the longitudinal direction of the fine grooves (21) and the circumferential direction of the roller (15) are approximately parallel to each other. It is preferable.

[0013] In another embodiment of the sheet member (20) of the present disclosure, The resin material is a fluororesin material. It is preferable.

[0014] In another embodiment of the sheet member (20) of the present disclosure, The compacted soil is bentonite mixed soil (BM) used to construct the soil water barrier layer (2). It is preferable.

[0015] The construction method of the present disclosure includes: A construction method for constructing a civil engineering structure (2) by compacting soil to be compacted by attaching a sheet member (20) made of a water-repellent resin material to the outer peripheral surface of a rolling wheel (15) having a circular cross section and provided on a rolling machine (10), comprising: The sheet member (20) has a plurality of fine grooves (21) extending in a predetermined direction on its surface, The sheet member (20) is attached to the outer peripheral surface of the roller (15) so that the longitudinal direction of the fine grooves (21) and the circumferential direction of the roller (15) are not perpendicular to each other. It is characterized by:

[0016] In another aspect of the construction method of the present disclosure, The civil engineering structure is a soil water barrier layer (2) constructed by compacting bentonite mixed soil (BM). It is preferable.

[0017] In the above description, to aid in understanding the present disclosure, the symbols used in the embodiments are added in parentheses to components corresponding to the embodiments, but each component is not limited to the embodiment defined by the symbol. [Effects of the Invention]

[0018] According to the technology disclosed herein, it is possible to effectively prevent the compacted soil from adhering to the roller wheels. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram illustrating an outline of a water impermeable layer constructed at a waste disposal site. [Figure 2] FIG. 2 is a schematic diagram illustrating a method for applying a water shielding layer. [Figure 3] FIG. 2 is a schematic diagram illustrating a general configuration of a vibration roller. [Figure 4] 1A is a schematic plan view showing a sheet member according to the present embodiment, and FIG. 1B is a schematic cross-sectional view showing a sheet member according to the present embodiment. [Figure 5] FIG. 2 is a schematic diagram showing a state in which the sheet member according to the present embodiment is attached to a rolling wheel. [Figure 6] FIG. 1 is a schematic diagram of a roller compactor test machine used in the demonstration test. [Figure 7] FIG. 1 is a schematic diagram illustrating the adhesion state of bentonite-mixed soil on a test specimen (Example) used in a demonstration test. [Figure 8] FIG. 1 is a schematic diagram illustrating the adhesion state of bentonite-mixed soil on a test specimen (Comparative Example 1) used in a demonstration test. [Figure 9]FIG. 1 is a schematic diagram illustrating the adhesion state of bentonite-mixed soil on a test specimen (Comparative Example 2) used in a demonstration test. [Figure 10] FIG. 1 is a schematic diagram illustrating the adhesion state of bentonite-mixed soil to a test specimen (Comparative Example 3) used in a demonstration test. [Figure 11] FIG. 1 is a schematic diagram illustrating the adhesion state of bentonite-mixed soil to a test specimen (Comparative Example 4) used in a demonstration test. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a sheet member and an application method according to this embodiment will be described with reference to the accompanying drawings.

[0021] [Waterproof layer] Before describing the sheet member according to the present embodiment, an outline of a water impermeable layer constructed in a waste disposal site will be described. The water impermeable layer is an example of a civil engineering structure according to the present disclosure.

[0022] As shown in Figure 1, in a waste disposal site 1, a water barrier layer 2 is constructed on the surface of excavated ground G, and waste 5 is contained inside the water barrier layer 2. The waste 5 is not particularly limited, but examples thereof include radioactive waste. To construct the water barrier layer 2, for example, bentonite-mixed soil BM, which is a mixture of on-site soil and bentonite, is used.

[0023] When constructing the water shielding layer 2, first, as shown in Fig. 2(A), bentonite mixed soil BM is spread and leveled on the surface of the ground G using heavy machinery HV such as a bulldozer or backhoe, or by manual spreading by a worker. Next, as shown in Fig. 2(B), the spread and leveled bentonite mixed soil BM is compacted to a desired layer thickness using a vibrating roller 10. In this way, the water shielding layer 2 in which the bentonite mixed soil BM is compacted is constructed on the surface of the ground G.

[0024] The schematic configuration of the vibrating roller 10 is shown in Figure 3. The vibrating roller 10 (an example of a roller compactor) comprises a vehicle body 11 with drive wheels 12, a roller compaction wheel 15 equipped with a vibration excitation device (not shown), and a support frame 18 that supports the roller compaction wheel 15. The roller compaction wheel 15 is made of steel, for example, and compacts the bentonite mixed soil BM by rolling while vibrating in the vertical direction due to the excitation force transmitted from the vibration excitation device.

[0025] Incidentally, bentonite mixed soil BM is a highly viscous and adhesive material, and so if the water content of the bentonite mixed soil BM is high, or if the daily temperature change at the work site is large and condensation is likely to occur on the roller 15 as the temperature drops, the bentonite mixed soil BM will adhere to the outer circumferential surface of the roller 15 during compaction work. If the bentonite mixed soil BM adheres to the outer circumferential surface of the roller 15, depending on the amount of adhesion, it may roughen the compacted surface, causing a problem that the quality standards for the water impermeable layer 2 will not be met. The sheet member of this embodiment is intended to prevent such bentonite mixed soil BM from adhering to the outer circumferential surface of the roller 15. The sheet member will be described in detail below.

[0026] [Sheet material] Fig. 4(A) is a schematic plan view showing the sheet member 20 according to this embodiment. Fig. 4(B) is a schematic cross-sectional view showing the sheet member 20 according to this embodiment. Fig. 5 is a schematic view showing the sheet member 20 according to this embodiment attached to the rolling wheel 15.

[0027] 4(A) and (B) is, for example, a plate-shaped fluororesin material, and in this embodiment is formed of polytetrafluoroethylene (hereinafter, PTFE). PTFE is a fluororesin material with very low surface free energy (surface tension) and excellent water and oil repellency. Note that the material of the sheet member 20 is not limited to PTFE, and for example, PFA (perfluoroalkoxyalkane), FEP (perfluoroethylenepropene copolymer), ETFE (ethylenetetrafluoroethylene copolymer), PVDF (polyvinylidene fluoride / vinylidene fluoride / polyvinylidene fluoride), etc. can be used.

[0028] The surface of the sheet member 20 is provided with a plurality of fine grooves 21 extending approximately parallel to one another by hairline processing. Hairline processing is a type of surface treatment that refers to a process of making a plurality of minute scratches the size of a hair in an approximately unidirectional direction, and a finish achieved by such processing. The method of hairline processing is not particularly limited, but examples include a method of rubbing a polishing roll against the surface of the sheet member 20 while rotating it in the opposite direction to the running direction of the sheet member 20, and a method of rubbing a polishing roll against the surface of the sheet member 20 while rotating it in the running direction of the sheet member 20 at a rotational speed faster than the running speed of the sheet member 20.

[0029] As shown in FIG. 5, the sheet member 20 is attached to the entire outer peripheral surface of the rolling wheel 15. The sheet member 20 is attached to the outer peripheral surface of the rolling wheel 15 so that the longitudinal direction of the fine grooves 21 (see FIG. 4) is substantially the same as the rotation direction of the rolling wheel 15, i.e., the circumferential direction CR of the rolling wheel 15. Multiple sheets of the sheet member 20 may be attached to the outer peripheral surface of the rolling wheel 15, or a single sheet may be wrapped and attached. The method of attaching the sheet member 20 is not particularly limited, but an adhesive or double-sided tape can be used. In this embodiment, the sheet member 20 is made of a fluororesin material such as PTFE. For this reason, when using an adhesive or double-sided tape, it is desirable to apply a primer to the back surface of the sheet member 20.

[0030] The thickness of the sheet member 20 can be, for example, 0.1 cm to 0.5 cm. The thickness of the sheet member 20 is not particularly limited, but is preferably a thickness that can ensure that the sheet member 20 is not easily damaged by the impact during compaction and that can be easily curved by hand to fit the outer circumferential surface of the rolling wheel 15. The width, length, and arrangement pitch of the fine grooves 21 are basically irregular, but at least one of them may be partially uniform.

[0031] The length of the microgrooves 21 is not particularly limited, but it is desirable that the length be longer than the circumferential length of the portion of the sheet member 20 attached to the outer peripheral surface of the rolling wheel 15 that comes into contact with the bentonite mixed soil BM (i.e., the portion covered by the bentonite mixed soil BM) when the bentonite mixed soil BM is compacted. With this configuration, microscopic gaps (gaps extending in the circumferential direction) that allow air to escape through the microgrooves 21 are secured between the bentonite mixed soil BM and the rolling surface of the sheet member 20 when the bentonite mixed soil BM is compacted.

[0032] Here, consider the case where a fluororesin plate with a smooth surface that has not been subjected to hairline treatment or the like is attached to the outer periphery of the rolling wheel 15 to compact the bentonite-mixed soil BM. The compaction energy transmitted from the rolling wheel 15 is applied as a linear pressure in the form of vertical stress, and with a smooth-surfaced fluororesin plate, the fluororesin plate itself acts like a suction cup. This is presumably because the bentonite-mixed soil BM covers the surface (the compacted surface) of the fluororesin plate, leaving almost no gap between the fluororesin plate and the bentonite-mixed soil BM, preventing air from escaping. For this reason, if a smooth-surfaced fluororesin plate is used, the adhesion of the bentonite-mixed soil BM cannot be sufficiently suppressed, resulting in a rough compacted surface.

[0033] In contrast, the sheet member 20 according to this embodiment has a plurality of fine grooves 21 formed on its surface by applying a hairline finish, and is attached to the outer peripheral surface of the rolling wheel 15 so that the longitudinal direction of the fine grooves 21 is substantially the same as the rotation direction (i.e., the circumferential direction CR) of the rolling wheel 15. In other words, even if the surface (rolling surface) of the sheet member 20 is covered with the bentonite mixed soil BM during compaction, a gap is secured between the sheet member 20 and the bentonite mixed soil BM through the plurality of fine grooves 21 to allow air to escape, thereby effectively suppressing the suction effect of the sheet member 20.

[0034] As a result, according to this embodiment, adhesion of the bentonite mixed soil BM is effectively inhibited, and it is also possible to effectively prevent the compacted surface of the water shielding layer 2 from becoming rough. Furthermore, by preventing the compacted surface from becoming rough, it is possible to satisfy the quality standards regarding unevenness of the finished surface, and it is also possible to ensure that the thickness of the water shielding layer 2 is greater than the design value. Furthermore, shaping and additional compaction work are no longer necessary, which makes it possible to improve productivity.

[0035] [Demonstration test] A demonstration test was conducted to confirm the adhesion suppression effect of the sheet member according to this embodiment. FIG. 6 is a schematic diagram of a roller compactor tester 100 used in the demonstration test. The roller compactor tester 100 is a tester that simulates the rolling wheels of a vibratory roller. Specifically, the roller compactor tester 100 includes a movable platform 110 that can move horizontally, a steel formwork 120 (only the bottom formwork is shown) placed on top of the movable platform 110, a roller body 130 with a semi-cylindrical cross section that simulates a rolling wheel, a support frame 140 that supports the upper end side of the roller body 130 so that it can swing freely, and a load device 160 that can transmit a load downward to the roller body 130.

[0036] In the demonstration test, a bentonite-mixed soil BM was manufactured and spread evenly on the top surface of a steel formwork 120 (bottom formwork). A preliminary load was then applied to create a simulated water-impermeable layer 150 on the top surface of the steel formwork 120. The bentonite-mixed soil BM was manufactured by mixing bentonite (Kunigel V1 (Kunigel is a registered trademark) manufactured by Kunimine Industries Co., Ltd.) with silica sand as the base material and adding water. The blend ratio of the silica sand as the base material was 80%, and the blend ratio of the bentonite was 20%. The blend ratios of the various silica sands as the base material were as follows: No. 7 silica sand: 15%, No. 5 silica sand: 33%, No. 4 silica sand: 32%, No. 3 silica sand: 9%, No. 2 silica sand: 5%, and No. 1 silica sand: 6%.

[0037] The bentonite mixed soil BM was produced by adding silica sand, bentonite, and water to a mixer in that order and stirring and mixing. The moisture content of the bentonite mixed soil BM was measured immediately after production. The moisture content was 12.7%. The simulated water impermeable layer 150 was prepared by placing a rectangular upper formwork (not shown) on the bottom formwork of the steel formwork 120, and pouring in bentonite mixed soil BM with a dry density of 2.054 Mg / m3, followed by a preliminary loading. The volume of the steel formwork 120 was 4500 cm3, the wet density was 2.315 g / cm3, the amount of bentonite mixed soil BM poured in was 10.418 kg (= 4500 cm3 × 2.315 g / cm3), the spread density was 1.389 g / cm3 (compaction degree: 60%), and the cross-sectional area of ​​the upper formwork of the steel formwork 120 was 900 cm2. The preliminary loading was carried out so that the thickness of the bentonite mixed soil BM was 8.3 cm (= 10.418 kg ÷ 1.389 g / cm3 ÷ 900 cm2).

[0038] Furthermore, condensation was simulated by spraying water using a spray bottle onto the upper surface of the fabricated simulated water impermeable layer 150. The amount of water sprayed was set at 60 cc / m, which is about three times the maximum amount of condensation, based on a conservative condition of 20 cc / m when the temperature drops by about 10°C per hour.

[0039] A total of five specimens S0 to S4 were fabricated for the demonstration test. Details of each specimen S0 to S4 are shown in Table 1.

[0040] [Table 1]

[0041] Specimen S0 is an example of the present disclosure in which multiple microgrooves are formed on the upper surface of a PTFE resin sheet by applying a hairline finish. Specimen S0 has dimensions of 100 mm x 100 mm and a thickness of 0.5 mm. Specimen S1 is Comparative Example 1 of the present disclosure and is an iron plate simulating a steel rolling wheel. Specimen S1 has dimensions of 100 mm x 100 mm and a thickness of 0.5 mm. Specimen S2 is Comparative Example 2 of the present disclosure and is a flat PTFE resin sheet whose surface has not been subjected to any processing. Specimen S2 has dimensions of 100 mm x 100 mm and a thickness of 0.5 mm. Specimen S3 is Comparative Example 3 of the present disclosure and is a PTFE resin sheet whose surface has been abraded for approximately 120 minutes. Specimen S3 has dimensions of 100 mm x 100 mm and a thickness of 0.5 mm. Specimen S4 is Comparative Example 4 of the present disclosure, and is a PTFE resin sheet whose surface was abraded for approximately 360 minutes. Specimen S4 has dimensions of 100 mm x 100 mm and a thickness of 0.5 mm.

[0042] As shown in Figure 6, the demonstration test was carried out by placing each of the test specimens S0 to S4 on the top surface of the simulated water impermeable layer 150, covering them with a rubber plate 180, and applying a load using the loading device 160 while moving the mobile platform 110 back and forth horizontally. The number of movements of the mobile platform 110 was set to 10 times (5 reciprocations), with 10.5 times being the standard number for when compaction is expected to be complete. The load applied by the loading device 160 was set to 400 N / cm (load 7.5 kgf / cm2, but without vibration), which is equivalent to the linear pressure of the rolling wheels of a macadam roller.

[0043] The evaluation was carried out by obtaining and comparing the amount of bentonite mixed soil BM attached, the attached area ratio, and the moisture content for each of the test specimens S0 to S4 after compaction was completed. The attached amount was obtained by scraping off the bentonite mixed soil BM attached to the surface of each of the test specimens S0 to S4 and weighing it. The attached area ratio was calculated by photographing the surface of each of the test specimens S0 to S4 with the bentonite mixed soil BM attached using a camera and identifying the number of pixels in which the bentonite mixed soil BM was visible from the obtained image data. The results for each of the test specimens S0 to S4 are shown in Table 2.

[0044] [Table 2]

[0045] For specimen S0 (Example), the amount of bentonite mixed soil BM adhered was 0.14 kg / m2, the bentonite mixed soil BM adhesion area ratio was 2.1%, and the moisture content was 12.4%. The moisture content was approximately the same as that of the other specimens. As shown in Figure 7, although there was partial adhesion of the bentonite mixed soil BM, the area of ​​each adhesion was very small and the adhesion was generally diffused. These results confirmed that the adhesion of bentonite mixed soil can be effectively suppressed by providing multiple fine grooves on the upper surface of the PTFE resin sheet using hairline processing.

[0046] For specimen S1 (Comparative Example 1), the amount of bentonite mixed soil BM attached was 1.41 kg / m2, the bentonite mixed soil BM attached area ratio was 21.7%, and the moisture content was 11.7%. The moisture content was approximately the same as that of the other specimens. As shown in Figure 8, the bentonite mixed soil BM was attached all over the surface, and the area was large. These results confirmed that when no sheet was attached to the roller, the amount of bentonite mixed soil attached was large, and the attached area ratio was also high.

[0047] Specimen S2 (Comparative Example 2) had an adhesion amount of bentonite mixed soil BM of 2.43 kg / m2, an adhesion area ratio of bentonite mixed soil BM of 40.1%, and a moisture content of 12.4%. The moisture content was approximately the same as that of the other specimens. As shown in Figure 9, the adhesion state of bentonite mixed soil BM was greater overall and over a larger area than that of the iron plate specimen S1. These results confirmed that even if a PTFE resin sheet with low surface free energy is attached, as long as the surface is smooth, the adhesion amount of bentonite mixed soil is greater and the adhesion area ratio is also higher than that of the iron plate (specimen S1) with high surface free energy.

[0048] Specimen S3 (Comparative Example 3) had an adhesion amount of bentonite-mixed soil BM of 0.89 kg / m2, an adhesion area ratio of bentonite-mixed soil BM of 18.1%, and a moisture content of 10.9%. The moisture content was approximately the same as that of the other specimens. As shown in Figure 10, the adhesion state of bentonite-mixed soil BM was generally less than that of specimens S1 and S2, but the area was larger than that of specimen S0 (Example). These results confirmed that while abrading the PTFE resin sheet can reduce the adhesion amount of bentonite-mixed soil to some extent, it cannot sufficiently reduce the adhesion area and roughens the compacted surface, thereby failing to ensure the quality and performance of the water barrier layer.

[0049] Specimen S4 (Comparative Example 4) had a bentonite-mixed soil BM adhesion amount of 0.53 kg / m2, a bentonite-mixed soil BM adhesion area ratio of 12.6%, and a moisture content of 10.3%. The moisture content was approximately the same as that of the other specimens. As shown in Figure 11, the adhesion state of the bentonite-mixed soil BM was generally less than that of specimen S3, but the adhesion area was larger than that of specimen S0 (Example). From these results, it was confirmed that as the PTFE resin sheet wears, the adhesion amount of the bentonite-mixed soil can be reduced, but the adhesion area cannot be sufficiently reduced, and as with specimen S3, the quality and performance of the water barrier layer cannot be guaranteed.

[0050] [Discussion of results] We consider why applying a hairline finish to the surface of a fluororesin sheet was effective in reducing the amount of bentonite-mixed soil that adhered to it.

[0051] When the rolling surface of a smooth, untreated fluororesin sheet is covered with bentonite soil, the gap between them disappears, leaving no room for air to escape. As a result, the fluororesin sheet acts like a suction cup, which is thought to have increased the amount of bentonite soil that adheres to it compared to the steel plate, which has a higher surface free energy. Furthermore, while wearing down the surface of the fluororesin sheet can partially create gaps between the rolling surface and the bentonite soil, this creates unevenness overall, making it impossible to suppress the suction cup effect and therefore unable to sufficiently reduce the amount of bentonite soil that adheres to it.

[0052] On the other hand, if numerous microgrooves are formed on the surface of a fluororesin sheet by hairline finishing, even if the compacted surface is covered with bentonite-mixed soil, a uniform gap can be secured between the compacted surface and the bentonite-mixed soil, which is thought to effectively suppress the suction action of the fluororesin sheet. In other words, the numerous microgrooves provide an escape route for air, suppressing the suction action and significantly reducing the amount of bentonite-mixed soil that adheres. From the above, it was confirmed that applying a hairline finish to the surface of a fluororesin sheet effectively reduces the amount of bentonite-mixed soil that adheres, making it possible to meet quality standards for the unevenness of the finished surface of the water barrier layer and further ensuring the performance and quality of the water barrier layer.

[0053] The present disclosure is not limited to the above-described embodiments, and can be appropriately modified and implemented within the scope of the present disclosure.

[0054] For example, in the above embodiment, the sheet member 20 is described as being attached to the outer peripheral surface of the rolling wheel 15 so that the fine grooves 21 are in substantially the same direction (i.e., substantially parallel) as the circumferential direction CR of the rolling wheel 15, but it is also possible to attach the sheet member 20 so that the fine grooves 21 intersect with the circumferential direction CR of the rolling wheel 15 at an angle other than 95 degrees (i.e., an angle that is not perpendicular). In this case as well, a gap that allows air to escape can be secured between the rolling surface of the sheet member 20 and the bentonite mixed soil BM, and the same effects as those of the above embodiment can be achieved.

[0055] Furthermore, in the above embodiment, the fine grooves 21 are described as being formed by hairline processing, but other processing methods can be used to process a plurality of fine grooves or scratches extending in approximately the same direction on the surface of the sheet member 20. Furthermore, in the above embodiment, bentonite mixed soil BM is described as an example, but the present disclosure can also be applied to the compaction of other clayey soils with strong adhesive properties. Furthermore, the technology of the present disclosure is not limited to water-impermeable layers at waste disposal sites, but can also be widely applied to the compaction work of other civil engineering structures such as cuttings and embankments. [Explanation of symbols]

[0056] 1...waste disposal site, 2...waterproof layer, 10...vibration roller, 15...rolling wheel, 20...sheet member, 21...fine groove, 100...roller compactor test machine, 110...mobile stand, 120...steel formwork, 130...roller body, 140...support frame, 150...simulated waterproof layer, 160...loading device, 180...rubber plate, S0 to S4...test specimen, BM...bentonite mixed soil

Claims

1. A sheet member that suppresses adhesion of compacted soil to the outer peripheral surface of a rolling wheel having a circular cross section provided on a rolling machine, The sheet member is made of a water-repellent resin material, and has a plurality of fine grooves extending in a predetermined direction on its surface. The sheet member is attached to the outer circumferential surface of the rolling wheel so that the longitudinal direction of the fine grooves and the circumferential direction of the rolling wheel are not perpendicular to each other. A sheet member characterized by:

2. The sheet member according to claim 1, The plurality of fine grooves are formed by hairline processing. A sheet member characterized by:

3. The sheet member according to claim 1 or 2, The sheet member is attached to the outer peripheral surface of the rolling wheel so that the longitudinal direction of the fine grooves and the circumferential direction of the rolling wheel are approximately parallel to each other. A sheet member characterized by:

4. The sheet member according to claim 1 or 2, The resin material is a fluororesin material. A sheet member characterized by:

5. The sheet member according to claim 1 or 2, The compacted soil is a bentonite-mixed soil used in constructing an earthen impermeable layer. A sheet member characterized by:

6. A construction method for constructing a civil engineering structure by compacting soil to be compacted by attaching a sheet member made of a water-repellent resin material to the outer peripheral surface of a rolling wheel having a circular cross section equipped on a rolling machine, the sheet member has a surface provided with a plurality of fine grooves extending in a predetermined direction; The sheet member is attached to the outer peripheral surface of the rolling wheel so that the longitudinal direction of the fine grooves and the circumferential direction of the rolling wheel are not perpendicular to each other. A construction method characterized by:

7. The construction method according to claim 6, The civil engineering structure is a soil water barrier layer constructed by compacting bentonite-mixed soil. A construction method characterized by:

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