Covering

Abstract

To provide a covering body capable of suppressing shear stress applied to a test specimen without causing water leakage. [Solution] Covering body 1 covers a cubic test specimen TB used for conducting tests to examine hydraulic characteristics with loads applied in three mutually perpendicular directions. Covering body 1 covers the surface of test specimen TB and includes fabric 11 made of high-strength fibers and a water-stopping material 11a applied to the surface of fabric 11 that comes into contact with test specimen TB.

Description

[Technical Field]

[0001] The present invention relates to a coating. [Background technology]

[0002] A known test examines hydraulic properties of a cubic rock mass or boulder specimen while applying loads in three mutually perpendicular directions. For example, hydraulic properties are expressed by the permeability coefficient and storage coefficient. The permeability coefficient indicates how easily water can pass through the rock mass or boulder. The storage coefficient indicates how much water the rock mass or boulder can store.

[0003] In the above test, water is poured into the surface of the test specimen, and the amount of water drained from the other surface of the test specimen is measured. Therefore, if the amount of water drained from the surface of the test specimen cannot be measured with high accuracy, the hydraulic properties cannot be investigated with high accuracy.

[0004] Therefore, for example, the test method described in Patent Document 1 uses a covering that covers the test specimen. The covering is made of silicone rubber. With a loading plate applying a load to the test specimen via the covering, water is injected from the surface of the test specimen through an injection port provided in the covering. This prevents water from leaking outside the covering. As a result, the amount of water discharged from the surface of the test specimen can be measured with high accuracy. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-018015 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, tension cracks, tension-shear cracks, shear cracks, and compressive failure are known to occur in the surface layer of a tunnel formed by excavating rock. Of these, tension cracks have a relatively large effect on hydraulic properties. Therefore, it is possible to apply a load to the test specimen so as to generate tensile cracks. In this case, if the shear stress applied to the test specimen is not sufficiently small, there is a high possibility that cracks other than tensile cracks will occur.

[0007] However, the covering is made of silicone rubber. Therefore, when a load is applied to the test specimen, a relatively large friction force is generated between the covering and the loading plate. This poses a problem in that a relatively large shear stress may be applied to the test specimen when the load is applied. Note that this type of problem may also occur when a specific load is applied to the test specimen other than when a load is applied to the test specimen so as to cause a tensile crack in the test specimen.

[0008] One of the objects of the present invention is to suppress the shear stress applied to the test specimen without causing water leakage. [Means for solving the problem]

[0009] In one aspect of the invention, the covering covers a cubic specimen used to conduct tests to determine hydraulic properties under load in each of three mutually perpendicular directions. The covering body covers the surface of the test specimen and includes a fabric made of high-strength fibers and a waterproofing material applied to the surface of the fabric that comes into contact with the test specimen. [Effects of the Invention]

[0010] The shear stress applied to the test specimen can be suppressed without causing water leakage. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of the covering body in a loaded state in the first embodiment. [Figure 2] FIG. 2 is a perspective view of the covering body in a loaded state in the first embodiment. [Figure 3] FIG. 2 is a plan view of the covering body in a loaded state in the first embodiment. [Figure 4] FIG. 2 is a front view of the covering body in a loaded state in the first embodiment. [Figure 5] FIG. 2 is a cross-sectional view of the covering body in a loaded state in the first embodiment. [Figure 6] FIG. 3 is a partially enlarged cross-sectional view of the covering body in a loaded state in the first embodiment. [Figure 7] FIG. 2 is a perspective view of the covering body in the unloaded state in the first embodiment. [Figure 8] FIG. 2 is a perspective view of the covering body in the unloaded state in the first embodiment. [Figure 9] FIG. 2 is a perspective view of a connector according to the first embodiment. [Figure 10] FIG. 2 is a perspective view of a connector according to the first embodiment. [Figure 11] FIG. 10 is a perspective view of a connector according to a first modified example of the first embodiment. [Figure 12] FIG. 10 is a perspective view of a connector according to a first modified example of the first embodiment. [Figure 13] FIG. 10 is a perspective view of a connector according to a second modified example of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the covering body of the present invention will be described with reference to FIGS.

[0013] First Embodiment (overview) The covering body of the first embodiment covers a cubic test body used for conducting tests to examine hydraulic characteristics in a state where loads are applied in three mutually orthogonal directions. The covering body covers the surface of the test specimen and includes a fabric made of high-strength fibers and a waterproofing material applied to the surface of the fabric that comes into contact with the test specimen.

[0014] According to this, the loading plate comes into contact with the fabric made of high-strength fibers. Fabric made of high-strength fibers has a lower coefficient of friction than silicone rubber. Therefore, the frictional force generated between the covering and the loading plate can be suppressed. As a result, the shear stress applied to the test specimen can be suppressed. Furthermore, the fabric made of high-strength fibers will not break even when water is injected at a relatively high water pressure. Additionally, the covering is provided with a water-stopping material, which prevents water from penetrating the covering. Thus, the above-mentioned covering can suppress the shear stress applied to the test specimen without causing water leakage. Next, the coating of the first embodiment will be described in more detail.

[0015] (composition) The coating 1 of the first embodiment will be described below using a right-handed Cartesian coordinate system having an x-axis, a y-axis, and a z-axis, as shown in Figures 1 to 10. Note that in this specification, a similar coordinate system is also used in Figures 11 to 13, which will be described later.

[0016] In this example, the x-axis direction, the y-axis direction, and the z-axis direction may be respectively expressed as the left-right direction of the covering body 1, the front-rear direction of the covering body 1, and the up-down direction of the covering body 1. Also, in this example, the positive x-axis direction, the negative x-axis direction, the positive y-axis direction, the negative y-axis direction, the positive z-axis direction, and the negative z-axis direction may be respectively expressed as the left direction of the covering body 1, the right direction of the covering body 1, the rear direction of the covering body 1, the front direction of the covering body 1, the up direction of the covering body 1, and the down direction of the covering body 1.

[0017] In this example, the covering body 1 covers the surface of the test specimen TB. In this example, the loading plates PBa and PBb apply loads to the test specimen TB in the x-axis direction, the y-axis direction, and the z-axis direction, respectively, via the covering body 1. In this example, the loading plates PBa and PBb apply loads to the test specimen TB by a mechanism not shown.

[0018] Fig. 1 is a view of the covering body 1 from a position to the left of, in front of, and above the covering body 1 (in other words, a left-front-upper perspective view) in a state in which the loading plates PBa and PBb are applying a load to the test body TB via the covering body 1 (in other words, a loaded state). Fig. 2 is a view of the covering body 1 from a position to the left of, in the rear of, and below the covering body 1 (in other words, a left-rear-lower perspective view) in the loaded state.

[0019] Fig. 3 is a view of the coated body 1 viewed from above the coated body 1 in a loaded state (in other words, a plan view). Fig. 4 is a view of the coated body 1 viewed from the front of the coated body 1 in a loaded state (in other words, a front view). Fig. 5 is a view of a cross section of the coated body 1 cut by a plane represented by line VV in Fig. 4, viewed in the positive direction of the x-axis.

[0020] Fig. 6 is an enlarged view of the area surrounded by dashed line VI in Fig. 5. Fig. 7 is a left-front upper perspective view of the covering body 1 in a state where the loading plates PBa and PBb and the tubes WT described below are removed (in other words, in an unloaded state). Fig. 8 is a left-rear lower perspective view of the covering body 1 in an unloaded state. 9 and 10 are perspective views of a connector 12 (described later) located on the front surface of the covering 1. FIG.

[0021] The test specimen TB is a cube with six square faces, two of which are perpendicular to the x-axis direction, two of which are perpendicular to the y-axis direction, and two of which are perpendicular to the z-axis direction. The test specimen TB is used to conduct tests to examine hydraulic characteristics while loads are applied in three mutually perpendicular directions (in this example, the x-axis direction, the y-axis direction, and the z-axis direction).

[0022] For example, hydraulic properties are expressed by the hydraulic conductivity and the storage coefficient. The hydraulic conductivity indicates how easily water can pass through a rock mass or rock. The storage coefficient indicates how much water the rock mass or rock can store.

[0023] In this example, the test specimen TB is a cubic rock mass or rock. In this example, the length of a side of the test specimen TB is 300 mm. However, the length of a side of the test specimen TB may be 100 mm to 600 mm.

[0024] Furthermore, the test specimen TB may be made of resin instead of bedrock or rock, such as ABS (Acrylonitrile Butadiene Styrene) resin, urethane resin, ASA (Acrylate Sthrene Acrylonitrile) resin, polypropylene resin, epoxy resin, acrylic resin, polycarbonate resin, or polyamide resin.

[0025] Furthermore, the test specimen TB may be configured to include a plurality of constituent bodies having a shape obtained by dividing a cube along a predetermined dividing plane, and the distance between the constituent bodies may be adjustable.

[0026] The pair of loading plates PBa that apply a load to the test specimen TB in the x-axis direction via the cover 1 are flat, square plates perpendicular to the x-axis direction. The pair of loading plates PBa that apply a load to the test specimen TB in the z-axis direction via the cover 1 are flat, square plates perpendicular to the z-axis direction.

[0027] A pair of loading plates PBb, which apply a load to the test specimen TB in the y-axis direction via the covering body 1, are flat, square plates perpendicular to the y-axis direction. As shown in Figures 5 and 6, the loading plate PBb has M through-holes PBb1 that penetrate the loading plate PBb in the thickness direction and are positioned in a grid pattern. M represents an integer of 2 or more. In this example, M represents 9. Note that M may be 4, 16, 25, etc.

[0028] A pair of loading plates PBa perpendicular to the x-axis direction apply a load to the test specimen TB in the x-axis direction via the covering body 1 by a mechanism not shown. A pair of loading plates PBb perpendicular to the y-axis direction apply a load to the test specimen TB in the y-axis direction via the covering body 1 by a mechanism not shown. A pair of loading plates PBa perpendicular to the z-axis direction apply a load to the test specimen TB in the z-axis direction via the covering body 1 by a mechanism not shown. In this way, in this example, the loads applied to the test specimen TB in three mutually orthogonal directions are controlled independently of one another.

[0029] The covering body 1 covers six surfaces of the test piece TB and is adhered to the surface of the test piece TB with an adhesive. As shown in FIG. 6, the covering 1 includes a fabric 11 and a waterproof material 11a. Fabric 11 covers the entire surface of specimen TB and is made of high-strength fibers. In this example, the high-strength fibers are ultra-high molecular weight polyethylene fibers. However, the high-strength fibers may also be aramid fibers, ultra-high-strength polyester fibers, carbon fibers, ultra-high-strength polyester fibers, high-strength polyamide fibers, or the like.

[0030] In this example, the fabric 11 is attached to the surface of the test piece TB without stitching different portions of the fabric 11. The fabric 11 may have portions that are folded along corners of the test piece TB.

[0031] The water-stopping material 11a is applied to the surface of the fabric 11 that comes into contact with the test piece TB. In this example, the water-stopping material 11a is made of a synthetic resin whose main component is acrylic silicone resin. The water-stopping material 11a may also be made of a synthetic resin whose main component is acrylic resin, silicone resin, fluororesin, urethane resin, or the like.

[0032] 1 to 6, fabric 11 has M through holes 11b on each of two surfaces perpendicular to the y-axis direction. M through holes 11b are positioned in a lattice pattern so as to correspond to M through holes PBb1 in loading plate PBb. Through holes 11b are located at the center of through holes PBb1 corresponding to the through holes 11b.

[0033] 6 to 8, the coating 1 has M connectors 12 on each of two surfaces perpendicular to the y-axis direction. The M connectors 12 are arranged in a lattice pattern so as to correspond to the M through-holes 11b, respectively.

[0034] The connector 12 is located at the center of the through hole PBb1 corresponding to the through hole 11b, similar to the through hole 11b corresponding to the connector 12. The connector 12 extends in the y-axis direction in the through hole PBb1.

[0035] As shown in FIGS. 6, 9, and 10, the connector 12 has a cylindrical portion 121 and a flange portion 122. The tubular portion 121 has a tubular shape having an internal space that communicates with the through-hole 11b corresponding to the connector 12. In this example, the tubular portion 121 has a cylindrical shape.

[0036] Flange portion 122 has a larger cross-sectional area than tubular portion 121 at the end of tubular portion 121 closer to fabric 11, and is fixed to fabric 11. In this example, flange portion 122 is annular. In this example, flange portion 122 is fixed to fabric 11 by being adhered with an adhesive to the surface of fabric 11 that does not contact test piece TB.

[0037] 6, the tube WT, through which water flows, is connected by fitting the tip of the tube WT into the cylindrical portion 121. Note that in FIGS. 1 to 6 and 13, portions of the tube WT other than the vicinity of the tip are not shown.

[0038] As a result, at the surface of the test piece TB where water is poured, water is poured onto the surface of the test piece TB via the tube WT and the connector 12. At the surface of the test piece TB where water is discharged, water is discharged from the surface of the test piece TB via the connector 12 and the tube WT.

[0039] As described above, the covering body 1 of the first embodiment covers a cubic test body TB used to conduct tests to examine hydraulic characteristics with loads applied in each of three mutually perpendicular directions. The covering 1 covers the surface of the test piece TB and includes a fabric 11 made of high-strength fibers and a waterproof material 11a applied to the surface of the fabric 11 that comes into contact with the test piece TB.

[0040] According to this, the loading plates PBa and PBb come into contact with the fabric 11 made of high-strength fibers. The fabric 11 made of high-strength fibers has a lower coefficient of friction than silicone rubber. Therefore, the frictional force generated between the covering body 1 and the loading plates PBa and PBb can be suppressed. As a result, the shear stress applied to the test specimen TB can be suppressed. Furthermore, the fabric 11 made of high-strength fibers will not break even when water is injected at a relatively high water pressure. In addition, since the covering body 1 is provided with a water-stopping material 11a, water can be prevented from penetrating the covering body 1. In this way, the covering body 1 can suppress the shear stress applied to the test specimen TB without causing water leakage.

[0041] Furthermore, the covering 1 of the first embodiment is adhered to the surface of the test piece TB with an adhesive.

[0042] This prevents friction from occurring between the covering 1 and the test specimen TB. Furthermore, even if gaps exist on the surface of the test specimen TB, the gaps can be filled with adhesive. This prevents water from moving near the surface of the test specimen TB. As a result, hydraulic properties can be examined with high accuracy. The covering 1 may be adhered to the surface of the test piece TB by a waterproofing material 11a.

[0043] Furthermore, in covering 1 of the first embodiment, fabric 11 has through-hole 11b. Covering 1 includes connecting body 12 having cylindrical tubular portion 121 having an internal space communicating with through-hole 11b of fabric 11, and flange portion 122 at one end of tubular portion 121, which has a larger cross-sectional area than tubular portion 121 and is fixed to fabric 11.

[0044] This allows flange portion 122 to be fixed to the surface of fabric 11 that does not come into contact with test specimen TB. This prevents a gap from being formed between the surface of test specimen TB and the surface of fabric 11 that comes into contact with test specimen TB. Furthermore, a tube WT for injecting or discharging water can be easily connected to tubular portion 121 of connector 12. This allows water to be injected or discharged via connector 12.

[0045] Furthermore, in the covering body 1 of the first embodiment, the connector 12 is adhered with an adhesive to the surface of the fabric 11 that does not come into contact with the test piece TB.

[0046] This can prevent a gap from being generated between the surface of fabric 11 that comes into contact with test piece TB and the surface of test piece TB. Instead of being adhered, the connector 12 may be fixed to a surface that does not contact the test piece TB by sewing.

[0047] Furthermore, in the covering 1 of the first embodiment, the high-strength fibers are ultra-high molecular weight polyethylene fibers.

[0048] This makes it possible to suppress the shear stress applied to the test specimen TB without causing water leakage.

[0049] The coated body 1 of the first embodiment is configured so that water is injected into or discharged from each of two faces perpendicular to the y-axis direction. The coated body 1 may be configured so that water is injected into or discharged from each of three or more faces. For example, the coated body 1 may be configured so that water is injected into or discharged from each of five faces, including two faces perpendicular to the y-axis direction, two faces perpendicular to the x-axis direction, and an end face in the positive direction of the z-axis.

[0050] <First Modification of First Embodiment> Next, a first modified example of the first embodiment will be described. The first modified example of the first embodiment differs from the first embodiment in that a through hole is provided in the flange of the connecting body. The following description will focus on the differences. In the description of the first modified example of the first embodiment, components that are assigned the same reference numerals as those used in the first embodiment are the same or substantially similar components.

[0051] (composition) 11 and 12, the connector 12A of the first modified example of the first embodiment has at least one through-hole 122a (11 in this example) in the flange portion 122. The through-hole 122a passes through the flange portion 122 in the y-axis direction. In this example, the through-hole 122a is cylindrical. However, the through-hole 122a may also be polygonal or elliptical cylindrical, for example.

[0052] In this example, connector 12A is adhered to the surface of fabric 11 that does not contact test piece TB with adhesive, with adhesive being filled in each through-hole 122a of flange portion 122.

[0053] The coating 1 of the first modification of the first embodiment can also achieve the same functions and effects as the coating 1 of the first embodiment. Furthermore, in the covering body 1 of the first modified example of the first embodiment, the connecting body 12A has a through-hole 122a in the flange portion 122.

[0054] According to this, by filling through-hole 122a of flange portion 122 with adhesive, the strength with which fabric 11 and connector 12A are fixed to each other can be increased.

[0055] <Second Modification of First Embodiment> Next, a description will be given of a covering according to a second modified example of the first embodiment. The covering according to the second modified example of the first embodiment differs from the covering according to the first embodiment in that the connector has a protruding portion that protrudes into the internal space. The following description will focus on the differences. In the description of the second modified example of the first embodiment, components that are assigned the same reference numerals as those used in the first embodiment are the same or substantially similar components.

[0056] (composition) 13, a connector 12B according to a second modification of the first embodiment has a protrusion 122b that protrudes into the interior space from a wall surface that defines the interior space. In this example, the protrusion 122b has an annular shape. Note that the connector 12B may also have a plurality of protrusions 122b spaced apart from one another in the circumferential direction.

[0057] In this example, protrusion 122b is located in the y-axis direction at the end of connector 12B on the flange 122 side. In this example, protrusion 122b is spaced a predetermined distance from the end face of connector 12B on the flange 122 side in the y-axis direction.

[0058] The coating 1 of the second modified example of the first embodiment can also achieve the same functions and effects as the coating 1 of the first embodiment. Furthermore, in the covering body 1 of the second modified example of the first embodiment, the connecting body 12B has a protruding portion 122b that protrudes into the internal space from the wall surface that defines the internal space.

[0059] However, if the tip of the tube WT for injecting or discharging water comes into contact with the surface of the test piece TB, there is a risk that the water will not be injected or discharged properly. In contrast, according to the covering body 1 of the second modified example of the first embodiment, when the tube WT for injecting or discharging water is inserted into the cylindrical portion 121, the tube WT comes into contact with the protrusion 122b, thereby separating the tip of the tube WT from the surface of the test piece TB. This allows the water to be injected or discharged properly.

[0060] The present invention is not limited to the above-described embodiment. For example, various modifications that can be understood by those skilled in the art may be made to the above-described embodiment without departing from the spirit of the present invention. [Explanation of symbols]

[0061] 1 Covering 11 Fabric 11a Water stop material 11b Through hole 12,12A,12B Concatenation 121 Cylinder part 122 flange 122a Through hole 122b Protrusion PBa,PBb loading plate PBb1 through hole TB specimen WT Tube

Claims

1. A covering body for covering a cubic test specimen used to conduct tests to examine hydraulic characteristics under loads applied in three mutually orthogonal directions, A fabric covering the surface of the test specimen and made of high-strength fibers; A water-stopping material applied to a surface of the fabric that comes into contact with the test specimen; Equipped with The fabric has through holes, The coating body is A covering body comprising a connecting body having a cylindrical tubular portion having an internal space communicating with the through hole of the fabric, and a flange portion at one end of the tubular portion having a cross-sectional area larger than that of the tubular portion and fixed to the fabric.

2. 10. The coating of claim 1, The coating is adhered to the surface of the test specimen by an adhesive.

3. The coated body according to claim 1 or claim 2, The connector has a protrusion that protrudes into the internal space from a wall surface that defines the internal space.

4. The coating according to claim 1 or claim 2, The connector is attached to a surface of the fabric that does not contact the test specimen with an adhesive.

5. The coated body according to claim 1 or claim 2, The connector is a covering body having a through hole in the flange portion.

6. The coating according to claim 1 or claim 2, The covering body, wherein the high strength fibers are ultra-high molecular weight polyethylene fibers.

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