Permeability evaluation device and permeability evaluation method

Abstract

To evaluate water permeability of a shear zone of a sample in an arbitrary shear state.SOLUTION: A water permeation evaluation device comprises a first holding member 3 that holds an upper surface side of a sample 2 and a second holding member 4 that holds a lower surface side of the sample 2, relatively moves the first holding member 3 and the second holding member 4 with shear means 6 to deform the sample 2, generates a displacement in the sample 2 to form a shear zone 5, causes water to flow in the shear zone 5 in a direction along the surfaces with water flow means 7, detects the state of water flow with water flow detection means 8, and evaluates a water permeation state of a portion of the shear zone 5 in the sample 2 in the direction along the surfaces with evaluation means 9.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water permeability evaluation apparatus for deforming a material to perform a water permeability evaluation, and a water permeability evaluation method.

Background Art

[0002] For example, when disposing of radioactive waste underground, in order to suppress the movement of nuclides due to the flow of groundwater, it is considered to use a material with extremely low water permeability as a buffer material such as overburden. As a material with extremely low water permeability, for example, a material having swelling properties (bentonite, or a mixture of bentonite and sand) has been studied.

[0003] When evaluating the material constituting the buried facility such as the buffer material, it is necessary to grasp the situation of the groundwater flow. In order to grasp the situation of the groundwater flow, it has become important to grasp the water permeability of the material such as the buffer material. For this reason, a technique has been proposed that can appropriately detect the movement of even an extremely small amount of water in a material with extremely low water permeability (for example, Patent Document 1).

[0004] On the other hand, it is important to grasp the strength of the buffer material such as overburden used for the disposal of radioactive waste, and in order to grasp the strength of the material constituting the ground such as the buffer material, the shear strength is examined. By grasping the shear strength, it becomes possible to evaluate the mechanical behavior of the buffer material such as overburden according to changes in the surrounding environment.

[0005] The situation of the groundwater flow in the material such as the buffer material requires a long-term evaluation in a state considering shear, and at present, it is necessary to grasp the situation regarding the generation of water channels when local deformation (shear deformation) occurs in the material.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the above situation, and an object thereof is to provide a water permeability evaluation device and a water permeability evaluation method capable of evaluating the water permeability of a shear band of a material in an arbitrary shear state (process).

Means for Solving the Problems

[0008] The water permeability evaluation device of the present invention according to claim 1 for achieving the above object is a first holding member for holding one surface side of a sample; a second holding member for holding the other surface side of the sample and restraining the sample between the first holding member; shearing means for relatively moving the first holding member and the second holding member to deform the sample and form a shear band in the sample; performing desired water flow at least in the direction along the one surface and the other surface with respect to the restrained sample before forming a shear band in the sample 、Make it possible to form a shear band in the desired water flow direction during deformation. and, water flow means for performing water flow in a direction along the surface with respect to the shear band formed in the sample after forming a desired water flow shear band in the sample; evaluating means for detecting the state of water flow by the water flow means and evaluating the water permeability situation of the shear band. It is characterized by the above.

[0009] The water permeability evaluation method of the present invention according to claim 2 for achieving the above object is to restrain a sample from both sides of a central axis, perform desired water flow on the restrained sample in a direction intersecting the central axis, displace and shear the sample after performing the desired water flow so that a shear band can be formed in the direction along the desired water flow, and perform water flow in the direction along the shear band, thereby evaluating the water permeability situation of the part including the shear surface.

[0010] And the water permeability evaluation method of the present invention according to claim 3 is characterized in that, in the water permeability evaluation method according to claim 2, the direction intersecting the central axis is the direction perpendicular to the central axis.

[0011] Also, the water permeability evaluation method of the present invention according to claim 4 is characterized in that, in the water permeability evaluation method according to claim 2 or claim 3, the displacement for shearing the sample is in the rotational direction.

[0012] That is, in the present invention, the water permeability evaluation device includes a first holding member that holds one surface side of the sample, a second holding member that holds the other surface side of the sample, a shearing means that relatively moves the first holding member and the second holding member to deform the sample to form a shear band in the sample, a water passing means that passes water in a direction along the surface with respect to the shear band formed in the sample, and an evaluation means that detects the state of water passing by the water passing means and evaluates the water permeability situation of the shear band.

[0013] Thereby, the shearing means deforms the sample to cause displacement in the sample, forms a shear band in the sample, the water passing means passes water in a direction along the surface with respect to the shear band of the sample, and the evaluation means evaluates the water permeability situation (water permeability ratio) of the shear band. Thereby, the water permeability situation can be evaluated by passing water through the shear band, and it becomes possible to evaluate the water permeability of the shear band of the sample in an arbitrary shearing state (process).

[0014] Incidentally, in the non-patent document (Yohhei Katayama, Hirohiro Kyo, Takashi Tsuchida, Hiroki Murakami, Research on the horizontal hydraulic conductivity of ground materials after shear deformation by a hollow torsional testing machine, Journal of the Japan Society of Civil Engineers, Series B3 (Ocean Engineering) Vol. 71, No. 2, I_1143-I_1148, 2015.), a technique is disclosed in which after applying consolidation and shear deformation to a clay sample, water is passed from the entire outer peripheral cylindrical surface to the hollow part of the hollow cylindrical sample to evaluate the water permeability situation.

[0015] However, although the technology disclosed in the non-patent literature is a technology for evaluating the water flow situation after applying shear deformation, it conducts water flow from the entire cylindrical surface of the outer periphery of the sample after shear caused by torsional displacement. Therefore, with the technology disclosed in the non-patent literature, although it is possible to infer the water permeability of the entire sample where shear occurs, water flow along the shear band is not carried out.

[0016] Therefore, it is naturally impossible to obtain the features of the present invention according to claim 1, such as being able to evaluate the water permeability of the shear band of the material in an arbitrary shear state (process), from the technology disclosed in the non-patent literature.

[0017] And in the water permeability evaluation device, a concave portion formed on the opposing surfaces of the first holding member and the second holding member for holding the sample, and a pressing means for bringing the peripheral portions of the opposing surfaces of the first holding member and the second holding member excluding the concave portion into surface contact when the sample is held, and a separating means for separating the first holding member and the second holding member before applying deformation to the sample to impart displacement to the sample to form a gap in the peripheral portion, and the water flow means is preferably a means for passing water through the shear band of the sample by passing water through the gap formed in the peripheral portion.

[0018] With the above-described configuration, after bringing the opposing surfaces other than the concave portions of the first holding member and the second holding member into contact by the pressing means, separating the first holding member and the second holding member by the separating means to provide a gap, applying displacement to the sample, and passing water through the gap, water can be passed through the shear band of the sample. Therefore, by passing water through a predetermined gap, water can be passed through the vicinity of the shear surface, and the water permeability situation of the shear band can be appropriately evaluated.

[0019] Also, it is preferable to provide a restraint maintaining means for maintaining the restraint state of the sample when separating the first holding member and the second holding member.

[0020] With the above-described configuration, it is possible to pass water to the vicinity of the shear band while maintaining the constrained state of the sample by the constraint maintaining means, and it is possible to accurately pass water to the shear band without changing the state of the sample after shear.

[0021] Further, it is preferable that the shearing means is means for relatively rotating the first holding member and the second holding member around an axis intersecting the holding surface of the sample to deform the sample.

[0022] With the above-described configuration, since shear is performed by displacement in the rotation direction, there is no restriction on the amount of displacement. Therefore, shear can be performed in a state of arbitrary displacement, and it is possible to evaluate the water permeability in a sheared state deformed to the state of the residual strength after the peak strength, and it is possible to evaluate the change in water permeability accompanying the progress of shear.

[0023] Further, the first holding member holds the upper surface side of the sample, the second holding member holds the lower surface side of the sample, the first holding member and the second holding member each have an annular recess in the opposing portion, and an accommodation space for accommodating an annular cylindrical sample is defined by the recess of the first holding member and the recess of the second holding member. When the sample is accommodated in the accommodation space, pressing means for pressing the first holding member against the second holding member in the axial core direction of the annular cylindrical sample and bringing the portions other than the recesses into surface contact, separation means for separating the first holding member and the second holding member of the portions other than the recesses in a state where the portions other than the recesses are in surface contact by the pressing means to form a desired gap while restraining the sample, shearing means for rotating the second holding member around the axial core of the annular cylindrical sample to an arbitrary angle to deform the sample, water passing means for passing water through the shear band of the sample by passing water through the gap between the outside and the inside of the recess, and evaluation means for detecting the state of water passing by the water passing means and evaluating the water permeability situation of the shear band are preferably provided.

[0024] With the above-described configuration, an annular cylindrical sample is accommodated in the accommodation space, and the first holding member is pressed against the second holding member in the axial direction of the annular cylindrical sample by the pressing means so that the portions other than the concave portions are in surface contact. With the sample being restrained, the first holding member and the second holding member at the portions other than the concave portion are separated by the separating means to form a desired gap between the first holding member and the second holding member. The second holding member is rotated by the shearing means to an arbitrary angle around the axis of the annular cylindrical sample to deform the sample. Water is passed through the gap between the outside and the inside of the concave portion by the water passing means, so that water is passed through the shear band of the sample, and the water passing state is detected by the evaluation means to evaluate the water permeability state of the shear band.

[0025] Thereby, shear is performed by deformation in the rotation direction to reduce the restriction on the displacement amount of the sample, and by passing water through a predetermined gap, water is passed through the vicinity of the shear surface while maintaining the restraint state of the sample. Therefore, it is possible to deform and shear until the state of the residual strength after the peak strength, and by passing water through the shear band without changing the state of the sample after shearing, the situation (water passing situation) of the water flowing through the shear band can be accurately grasped. For this reason, it becomes possible to evaluate the water permeability of the shear band of the material in an arbitrary shear state (process). That is, it is possible to evaluate the water permeability in the shear state where the displacement is made to the state of the residual strength after the peak strength, and it is possible to evaluate the change in water permeability accompanying the progress of shear.

[0026] Further, by passing water from the annular concave portion of the second holding member toward the annular concave portion of the first holding member, or from the annular concave portion of the first holding member toward the annular concave portion of the second holding member, it is preferable that the apparatus further includes vertical water passing means for passing water vertically across the shear band of the sample, and the evaluation means has a function of detecting the water passing state by the vertical water passing means and evaluating the water permeability state across the shear band.

[0027] With the above-described configuration, it is possible to evaluate the water permeability state in the vertical direction with respect to the sample.

[0028] Further, it is preferable to provide a saturation means for saturating the sample (with water) by supplying water to the sample before water is passed through by the water passage means.

[0029] With the above-described configuration, it is possible to supply water to the sample before passing water to saturate the sample (and discharge air), and it is possible to accurately evaluate the state of water passing through the sample without being affected by bubbles or the like.

[0030] Further, it is preferable to evaluate the water permeability of the portion including the shear surface by shearing and deforming the sample and passing water in the direction along the shear band.

[0031] Thereby, the water permeability of the shear band of the material in an arbitrary shear state (process) can be evaluated. That is, the water permeability of the shear band generated by the displacement due to the result of applying a shear force can be evaluated.

[0032] Further, the deformation of the sample is characterized by being in the rotational direction.

[0033] Thereby, since shearing and deforming are performed in the rotational direction, there is no restriction on the displacement amount. For this reason, shearing can be performed in an arbitrary deformation state, a shear force is applied to the sample to deform it, the water permeability can be evaluated until the state of the residual strength after the peak strength, and the change in water permeability accompanying the progress of shearing can be evaluated.

Advantages of the Invention

[0034] The water permeability evaluation apparatus and the water permeability evaluation method of the present invention can evaluate the water permeability of the shear band of the material in an arbitrary shear state (process).

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0036] FIG. 1 shows a conceptual configuration situation conceptually representing the device for explaining the water permeability evaluation device of the present invention. FIG. 1(a) is the state before deforming the sample (before displacement occurs in the sample), and FIG. 1(b) is the state after deforming the sample (after displacement occurs in the sample).

[0037] As shown in the figure, the water permeability evaluation device 1 of the present invention is provided with a first holding member 3 for holding the upper surface side (one surface side) of a sample (low water permeability material: for example, a material containing bentonite) 2 and a second holding member 4 for holding the lower surface side (the other surface side) of the sample 2. That is, the first holding member 3 and the second holding member 4 are configured to restrain the sample from both sides in the one central axis direction.

[0038] And a shearing means 6 is provided for relatively moving the first holding member 3 and the second holding member 4 to deform the sample 2 and give displacement to the sample 2 to form a shear zone 5 in the sample 2.

[0039] Furthermore, there is provided a water-permeation means 7 for performing water permeation (desired water permeation / water permeation) along the surface direction (in a direction intersecting a central axis) with respect to the shear band 5 of the sample 2. The water-permeation state by the water-permeation means 7 is detected by a water-permeation detection means 8. The water-permeation state detected by the water-permeation detection means 8 is input to an evaluation means 9, and the evaluation means 9 evaluates the water-permeation situation (such as the ratio of water permeation based on the water-permeability coefficient) in the surface direction of the portion of the shear band 5 of the sample 2.

[0040] Therefore, it is possible to evaluate the water-permeation situation by passing water through the shear band 5 (while passing water under a pressurized state), and by arbitrarily setting the displacement state by the shearing means 6, it becomes possible to evaluate the water permeability of the shear band 5 of the sample 2 in an arbitrary shear state (process: arbitrary shear process).

[0041] FIG. 2 shows a conceptual configuration situation conceptually representing the apparatus for explaining a water-permeability evaluation apparatus according to an embodiment of the present invention.

[0042] As shown in the figure, the water-permeability evaluation apparatus 11 is provided with a first holding member 13 for holding the upper surface side (one surface side) of an annular sample (low water-permeability material: for example, a material containing bentonite) 12, and a second holding member 14 for holding the lower surface side (the other surface side) of the sample 12. Concave portions 13a and 14a for holding the annular sample 12 are respectively formed on the opposing surfaces of the first holding member 13 and the second holding member 14. An accommodation space is formed by the concave portion 13a and the concave portion 14a.

[0043] There is provided a pressurizing means 15 for lowering the first holding member 13 toward the second holding member 14 (downward), and by lowering the first holding member 13 by the pressurizing means, the peripheral portions (surfaces 13b, 14b) excluding the concave portions 13a, 14a of the opposing surfaces of the first holding member 13 and the second holding member 14 are brought into surface contact.

[0044] From the state where the peripheral parts (surfaces 13b and 14b) of the first holding member 13 and the second holding member 14 are in surface contact, the first holding member 13 and the second holding member 14 are separated, and a rotation driving means 16 is provided as a shearing means for rotating the second holding member 14 around the axis of the annular cylindrical sample 12 (the central axis extending in the vertical direction in the figure) to an arbitrary angle to cause displacement in the sample 12. By rotating the second holding member 14 to an arbitrary angle by the rotation driving means 16, displacement occurs in the sample 12 and the sample 12 is sheared, and a shear band 17 parallel to the peripheral parts (surfaces 13b and 14b) of the first holding member 13 and the second holding member 14 is formed in the sample 12.

[0045] Before deforming the sample 12 by rotating the second holding member 14 to an arbitrary angle by the rotation driving means 16 to give displacement to the sample 12, while the sample 12 is in a constrained state (by the constraining means described later), a lifting means 18 is provided as a separating means for raising a part of the first holding member 13 to separate the peripheral parts (surfaces 13b and 14b) of the first holding member 13 and the second holding member 14. By raising a part of the first holding member 13 by the lifting means 18, a predetermined gap S is formed between the peripheral parts (surfaces 13b and 14b) of the first holding member 13 and the second holding member 14.

[0046] A water passing means 19 is provided for passing water pressurized at a predetermined pressure through the gap between the peripheral parts (surfaces 13b and 14b) between the first holding member 13 and the second holding member 14. Also, a saturating means is provided for saturating the sample 12 with water by supplying water to the sample 12 before passing water by the water passing means 19.

[0047] That is, a water supply means 24 for supplying water for saturation is provided to the second holding member 14, and a downstream passage 25 is formed in the second holding member 14 to which the water supply means 24 is connected and communicates with the lower surface of the sample 12. An upstream passage 26 communicating with the upper surface of the sample 12 is formed in the first holding member 13, and a discharge passage 27 is connected to the upstream passage 26. A valve 28 is provided in the discharge passage 27.

[0048] Before water is passed through by the water passage means 19, the valve 28 is opened to supply water from the water supply means 24. Water is supplied from the downstream passage 25 to the sample 12, and the water is sent to the upstream passage 26 together with the air accumulated in the sample 12. The sent water is discharged from the discharge passage 27 together with the air bubbles, and the air is discharged from the sample 12 and the sample 12 is saturated with water.

[0049] With the sample 12 in a saturated state, by passing pressurized water through the gap between the peripheral parts (surfaces 13b, 14b) of the first holding member 13 and the second holding member 14 by the water passage means 19, the water pressurized at a predetermined pressure is passed through the shear band 17 of the sample 12.

[0050] A detection means 20 for detecting the state of water passage (such as the amount of water passed) by the water passage means 19 is provided, and the state of water passage detected by the detection means 20 is input to the evaluation means 21. In the evaluation means 21, the water permeability state of the shear band 17 (for example, the ratio of water permeability based on the water permeability coefficient) is evaluated from the state of water passage along the shear band 17.

[0051] In the water permeability evaluation device 11 described above, an annular cylindrical sample 12 is accommodated in the accommodation space formed by the concave portions 13a and 14a of the first holding member 13 and the second holding member 14, and the first holding member 13 is pressed against the second holding member 14 in the axial direction of the test 12 by the pressing means 15 so that the peripheral parts (surfaces 13b, 14b) excluding the concave portions 13a, 14a are in surface contact.

[0052] Before displacing the sample 12, with the sample 12 in a constrained state (by the constraint means described later), the lifting means 18 separates the first holding member 13 and the second holding member 14 at the peripheral parts (surfaces 13b, 14b) excluding the concave portions 13a, 14a, and a gap S parallel to the shear band 17 is formed at the peripheral parts (surfaces 13b, 14b) excluding the concave portions 13a, 14a. The gap S can be arbitrarily formed with a desired dimension.

[0053] The second holding member 14 is rotated by the rotational drive means 16 to an arbitrary angle to deform the sample 12. By deforming the sample 12, displacement occurs in the sample 12 and a shear band 17 is formed in the sample 12.

[0054] Sample 12 is saturated with water, and water pressurized at a predetermined pressure is passed through the gap between the outer and inner sides of the recesses 13a and 14a of the first holding member 13 and the second holding member 14 by the water passage means 19. By passing water through the water passage means 19, the pressurized water is passed along the direction along the surface of the shear band 17 of the sample 12, and the state of water passage (such as the amount of water passed) is detected by the detection means 20.

[0055] The detection information of the detection means 20 is input into the evaluation means 21, and the water permeability situation (for example, the water permeability coefficient) of the shear band 17 is evaluated by the evaluation means 21 from the state of water passage along the shear band 17.

[0056] Thus, shear is carried out by deformation in the rotational direction, that is, by causing a displacement in the rotational direction in the sample 12, the restriction on the displacement amount is reduced, water pressurized to a predetermined gap S is passed through, water is passed along the direction along the surface of the shear band 17 with respect to the vicinity of the shear band 17 of the sample 12 in the saturated state, and water can be passed through the vicinity of the shear band 17 while maintaining the constrained state of the sample 12.

[0057] Therefore, the sample 12 can be deformed and sheared until the state of the residual strength after the peak strength, and by passing water through the shear band without changing the state of the sample 12 after shearing, the situation of water flowing through the shear band 17 (water passage situation) can be accurately grasped. For this reason, it becomes possible to evaluate the water permeability of the shear band of the sample 12 in an arbitrary shear state (process). That is, it is possible to evaluate the water permeability in the shear state in which displacement is caused until the state of the residual strength after the peak strength, and it is possible to evaluate the change in water permeability accompanying the progress of shear.

[0058] That is, by deforming the sample 12 by shear in the rotational direction, there is no restriction on the shear amount (displacement amount), and it is possible to evaluate the water permeability in the state (shear state) in which the sample 12 is deformed until the state of the residual strength after the peak strength, and it is possible to evaluate the change in water permeability accompanying the progress of shear.

[0059] Based on FIGS. 3 to 7, the configuration of the water permeability evaluation device 11 will be specifically described.

[0060] FIG. 3 shows a schematic cross-sectional view representing the overall situation of the water permeability evaluation device 11, FIG. 4 shows a situation where the first holding member 13 of the water permeability evaluation device 11 is rising, FIG. 5 shows a perspective view of the constituent members of the main part of the water permeability evaluation device 11 disassembled, FIG. 6 shows an external view of the second holding member 14, and FIG. 7 shows an external view of the first holding member 13.

[0061] Mainly, as shown in FIGS. 3 to 6, a rotation driving means 16 is provided on the lower frame 31 of the water permeability evaluation device 11, and a driving base 32 is fixed to the driving part of the rotation driving means 16 (shearing means). A base 33 constituting the second holding member 14 is attached to the driving base 32 to form a holding base 34.

[0062] An annular lower holding part 35 is formed on the upper surface of the base 33. The holding base 34 is provided with a lower cylindrical part 36 arranged outside the base 33 and a lower column part 37 arranged inside the base 33. The upper surface heights of the lower cylindrical part 36 and the lower column part 37 are formed higher than the upper surface height of the lower holding part 35, and the lower cylindrical part 36 and the lower column part 37 are formed at the same height. The lower surface of the lower side of the annular recess 14a is formed by the upper surface of the lower holding part 35.

[0063] A horizontally extending horizontal water passage 38 (water passage means 19) is formed in the base 33, and pressurized water adjusted to a predetermined pressure is supplied to the horizontal water passage 38. A vertical water passage 39 is formed in the lower column part 37, the lower end of which communicates with the horizontal water passage 38 and the upper end of which opens to the upper surface of the lower column part 37. The pressurized water sent to the horizontal water passage 38 is sent from the vertical water passage 39 to the upper surface of the lower column part 37.

[0064] Mainly, as shown in FIGS. 3 to 5 and FIG. 7, a screw shaft 41 extending in the vertical direction is provided on the frame 31, and the screw shaft 41 is rotationally driven in conjunction. A nut member 42 is screwed onto the screw shaft 41, and a loading frame 43 is attached to the nut member 42 (pressing hand). A lifting base 45 is provided below the loading frame 43 via a load cell 44.

[0065] As shown in FIG. 4, a pressing member 46 (first holding member 13) is provided on the lifting base 45. The pressing member 46 is composed of a notch cylinder portion 47 in which a central portion of a cylindrical main body forms a predetermined width in the radial direction and is notched, and a pressing ring 48 (first holding member 13) provided at the lower end of the notch cylinder portion 47.

[0066] As shown in FIG. 5, an upper holding portion 49 (first holding member 13) is provided in a notch space 47a of the notch cylinder portion 47 of the pressing member 46. The upper holding portion 49 is composed of a plate-shaped upper frame member 51 arranged in the notch space 47a and a cylindrical upper column portion 52 provided on the lower surface of the upper frame member 51. Flange portions 53 are formed at both ends of the upper frame member 51 on the outside of the notch space 47a (outside in the radial direction of the notch cylinder portion 47).

[0067] The upper holding portion 49 is provided so as to be vertically movable inside the notch space 47a with respect to the notch cylinder portion 47. On the other hand, an upper cylinder portion 54 is arranged on the upper surface of the lower cylinder portion 36, and a flange 55 that faces the flange portion 53 and can be fastened to the flange portion 53 is formed on the upper cylinder portion 54.

[0068] And, as shown in FIG. 4, the outer peripheral edges of the lower cylinder portion 36 and the upper cylinder portion 54 are connected by a ring flange 58, and a drain channel 59 is connected to the ring flange 58. A circumferential groove 58a is formed inside the ring flange 58, and the circumferential groove 58a communicates with the drain channel 59. That is, the water that has passed through the sample 12 radially is guided from the circumferential groove 58a to the drain channel 59 and discharged.

[0069] As shown in Fig. 5, when the upper holding portion 49 is pressed downward, the lower surface of the upper cylindrical portion 54 comes into contact with the upper surface of the lower cylindrical portion 36 (contact between metal surfaces), and the lower surface of the upper column portion 52 comes into contact with the upper surface of the lower column portion 37 (contact between metal surfaces).

[0070] As shown in Fig. 3, by rotating the screw shaft 41 to lower the loading frame 43 via the nut member 42, the upper holding portion 49 composed of the load cell 44, the lifting base 45, the pressing member 46, and the pressing ring 48 is pressed downward.

[0071] In a state where the upper holding portion 49 is pressed downward, the position of the lower surface of the upper column portion 52 in the height direction is located below the position of the pressing ring 48 in the height direction. As a result, an annular recess 13a is formed between the upper surface of the lower holding portion 35 and the lower surface of the pressing ring 48. The recess 13a and the aforementioned annular recess 14a define an accommodation space for accommodating the annular cylindrical sample 12. The sample 12 is accommodated in the accommodation space with the porous member 40 (a member for evenly passing water through the surface of the sample 12) interposed vertically.

[0072] With a gap formed between the lower cylindrical portion 36 and the upper cylindrical portion 54 and between the contact surfaces of the lower column portion 37 and the upper column portion 52, pressurized water is passed through the horizontal water passage 38 and the vertical water passage 39, and the pressurized water is drained into the drain passage 59 of the ring flange 58 through the gap (through the sample 12). That is, with the annular cylindrical sample 12 accommodated in the accommodation space, pressurized water is passed from the inner side to the outer side in the radial direction of the sample 12 (water passage means 19).

[0073] On the other hand, a venting common flow path 61 is formed across the upper column portion 52, the upper frame member 51, and the flange portion 53. The flow path 61 communicates with the vertical water passage 39 and can be opened by a valve 62 (see Fig. 9 described later). Although not shown, vertical water passage means for passing a predetermined amount of pressurized water is provided vertically (above and below the sample 12: crossing the shear band to be described later) from the second holding member 14 to the first holding member 13 (or vice versa).

[0074] Position detection means 65 for detecting the lifting position of the lifting base 45 (the first holding member 13) is provided. That is, a sensor rod 66 is provided on the frame 31, and a detection arm 67 for detecting the position with respect to the sensor rod 66 is provided on the lifting base 45. Based on the detection result of the load cell 44 and the detection result of the position detection means 65, it is evaluated whether the lifting position of the first holding member 13 is performed in a desired pressurized state.

[0075] A screw jack 71 is provided at the upper part of the frame 31, and a lifting plate 72 that is lifted by operating the screw jack 71 is provided. The lifting plate 72 is independently liftable with respect to the loading frame 43. The upper end of a connecting bar 73 is attached to the lifting plate 72, and the lower end of the connecting bar 73 is attached to the flange portion 53 of the upper holding portion 49. Reference numeral 74 in the figure is a load detector.

[0076] With the upper holding portion 49 being pressed downward, the flange portion 53 and the flange 55 of the upper cylindrical portion 54 can be joined, and the lifting plate 72 that is lifted by operating the screw jack 71 can be raised. Thereby, with the sample 12 being pressed against the lower holding portion 35 by the pressing ring 48 of the pressing member 46 (in a state where the sample 12 is restrained: restraining means), the upper holding portion 49 (the upper column portion 52) and the upper cylindrical portion 54 are raised to form a predetermined gap at the contact surface with the lower cylindrical portion 36 and the lower column portion 37 (separating means).

[0077] Also, gap detection means (dial gauge) 75 is provided downward from the upper part of the frame 31, and the tip of the detection portion 76 of the dial gauge 75 is in contact with the upper surface of the lifting plate 72. That is, the lifting position of the lifting plate 72 (the upper holding portion 49, the upper column portion 52, the upper cylindrical portion 54) with respect to the frame 31 by the dial gauge 75, that is, the gap at the contact surface between the upper column portion 52 and the lower column portion 37 and between the upper cylindrical portion 54 and the lower cylindrical portion 36 is detected.

[0078] The sample 12 is accommodated with the porous member 40 interposed in the accommodation space defined by the concave portion 13a of the first holding member 13 and the concave portion 14a of the second holding member 14. The first holding member 13 is pressed against the second holding member 14 in the axial direction of the annular cylindrical sample 12 by the pressing means, and the portions other than the concave portion 13a and the concave portion 14a are brought into surface contact.

[0079] With the sample 12 constrained by the pressing ring 48 of the elevating base 45, the elevating plate 72 is raised to separate the first holding member 13 and the second holding member 14 at the portions other than the concave portion 13a and the concave portion 14a, and a gap is formed at the contact surfaces between the upper column portion 52 and the lower column portion 37, and between the upper cylindrical portion 54 and the lower cylindrical portion 36. The second holding member 14 is rotated by the rotation driving means 16 to an arbitrary angle about the axis of the annular cylindrical sample 12 to deform the sample 12. As a result, the sample 12 is deformed and sheared, and a shear band 17 on a horizontal plane is formed.

[0080] After the sample 12 is saturated with water, pressurized water is supplied to the horizontal through-water channel 38 and the vertical through-water channel 39 (water passing means), and water passing is performed from the inside to the outside gap between the concave portion 13a of the first holding member 13 and the concave portion 14a of the second holding member 14. As a result, water is directly passed through the shear band 17 of the sample 12, and water passing along the shear band 17 is carried out. The state of the water passing (such as the amount of water passing) drained from the drainage channel 59 is detected by the detecting means 20, and the information of the detecting means 20 is sent to the evaluating means 21 to evaluate the water permeability situation of the shear band 17.

[0081] Therefore, the sample 12 is deformed by the shearing means, water passing is performed in the direction along the surface with respect to the shear band 17 of the sample 12 by the water passing means, and the water permeability situation (water permeability ratio) of the pressurized water passing through the shear band 17 is evaluated by the evaluating means 21. For this reason, the water permeability situation can be evaluated by passing water through the shear band 17, and it becomes possible to evaluate the water permeability of the shear band 17 of the sample 12 in an arbitrary shearing state (process).

[0082] Based on FIGS. 8 to 12, the operation of the water permeability evaluation apparatus described above will be further specifically described.

[0083] FIG. 8 shows a flowchart representing the operation of the process for evaluating the water flow situation, FIG. 9(a) shows a side view of the state where the sample 12 is set, FIG. 9(b) shows a side view of the state where the width of the gap (upper and lower gaps) at the contact surface between the upper column part 52 and the lower column part 37, and between the upper cylinder part 54 and the lower cylinder part 36 is zero, FIG. 10(a) shows a side view of the state where the width between the upper and lower corners is adjusted to a predetermined width, FIG. 10(b) shows a side view of the state where pressurized water is flowing horizontally, FIG. 11 shows a plan view of the state explaining the flow state of the pressurized water, and FIG. 12 shows a graph representing the relationship between the shear displacement and the shear stress.

[0084] As shown in FIG. 8, in step S1, the installation of the sample 12 and the preparation of the apparatus are carried out. That is, as shown in FIG. 9(a), the upper cylinder part 54 is arranged with respect to the lower cylinder part 36, and the lower surface of the upper cylinder part 54 and the upper surface of the lower cylinder part 36 are brought into surface contact (with the gap being zero), and the peripheries are connected to each other by the ring flange 58.

[0085] With the upper cylinder part 54 fixed, the sample 12 is placed on the annular recess 13a (accommodation space) formed by the lower holding part 35 and the lower cylinder part 36. In this state, the loading frame 43 (see FIG. 3) is lowered, the pressing member 46 and the upper holding part 49 are lowered, and the lower surface of the upper column part 52 and the lower surface of the lower column part 37 are brought into surface contact. Thereby, the sample 12 is constrained in the accommodation space.

[0086] As shown in FIG. 9(b), the flange part 53 of the upper holding part 49 and the flange 55 of the upper cylinder part 54 are fastened and integrated by bolts. If necessary, the loading frame 43 (see FIG. 3) is lowered, and the sample 12 is consolidated in the accommodation space. The valve 62 of the flow path 61 is opened, and water is supplied to the horizontal through-water path 38, the vertical through-water path 39, and the flow path 61 by the water passing means 19, air in the horizontal through-water path 38, the vertical through-water path 39, and the flow path 61 is removed, the inside of the flow path is saturated with water, and the valve 62 is closed.

[0087] As shown in FIG. 8, the gap is adjusted in step S2. That is, as shown in FIG. 10(a), with the sample 12 pressed against the lower holding portion 35 by the pressing member 46 (while the sample 12 is restrained), the upper holding portion 49 (upper column portion 52) and the upper cylinder portion 54 are raised. As a result, as shown in FIG. 10(b), a predetermined gap is formed on the contact surface between the lower cylinder portion 36 and the lower column portion 37.

[0088] As shown in FIG. 8, in step S3, water is passed (desired water flow) through the horizontal water passage 38 and the vertical water passage 39 to supply water to the sample 12 (open the valve 30 shown in FIG. 10). That is, with the sample restrained from both sides in the one central axis direction by the first holding member 3 (see FIG. 1) and the second holding member 4 (see FIG. 1), water is passed (desired water flow) in a direction intersecting the one central axis (in the direction from which water is discharged from the valve 30 shown in FIG. 10).

[0089] In addition (or separately from the water flow through the horizontal water passage 38 and the vertical water passage 39), as shown in FIG. 10(a), the valve 28 is opened to supply water from the water supply means 24, supply water to the sample 12 from the downstream passage 25, and send water to the upstream passage 26 together with the air accumulated in the sample 12. As a result, water is sent from below the sample 12 upward, water is discharged from the discharge passage 27 together with the bubbles, air is discharged from the sample 12, and the sample 12 is saturated with water (saturation means).

[0090] Note that as the saturation means, if air can be discharged only by the water flow from the horizontal water passage 38 and the vertical water passage 39, it is also possible to omit the water supply means 24, the downstream passage 25, the upstream passage 26, the discharge passage 27, and the valve 28. Also, it is possible to adopt a configuration in which water is passed through the horizontal water passage 38 and the vertical water passage 39 and the water passing through the sample 12 is drawn at a negative pressure.

[0091] Returning to FIG. 8, in step S4, the drive base 32 is rotated, and rotated about the axis of the annular cylindrical sample 12 to an arbitrary desired angle (between an angle exceeding 0 degrees and an arbitrary angle of 360 degrees or more). For example, it is rotated to an angle at which the state of the residual intensity after the peak intensity is obtained. In step S5, the drive base 32 is stopped. As a result, a (horizontal) shear band 17 intersecting the axis is formed in the sample 12.

[0092] In step S6, water is passed (pressurized water is supplied) through the horizontal through-water channel 38 and the vertical through-water channel 39. That is, the valve 30 shown in FIG. 10 is opened, and pressurized water is supplied to the horizontal through-water channel 38 and the vertical through-water channel 39. As a result, as shown in FIG. 11(a), water is passed from the center of the sample 12 toward the outside (with respect to the gap from the inside to the outside of the concave portion 13a of the first holding member 13 and the concave portion 14a of the second holding member 14), and is drained from the drain channel 59. Incidentally, the direction of water passage can also be from the outside of the sample 12 toward the center (with respect to the gap from the outside to the inside of the concave portion 13a of the first holding member 13 and the concave portion 14a of the second holding member 14) as shown in FIG. 11(b) (it is also possible to pass water from the side of the drain channel 59).

[0093] As shown in FIG. 10(b), pressurized water is passed along the direction along the surface of the shear band 17 of the sample 12, and the state of water passage (such as the amount of water passed) is detected by the detection means 20. The detection information of the detection means 20 is input to the evaluation means 21, and the water permeability situation (for example, the permeability coefficient) of the shear band 17 is evaluated by the evaluation means 21 from the state of water passage along the shear band 17.

[0094] Therefore, water can be directly passed through the shear band 17 of the sample 12, and water passage along the shear band 17 can be carried out. The state of water passage (such as the amount of water passed) drained from the drain channel 59 is detected by the detection means 20.

[0095] For example, when evaluating the water permeability situation in the state of the residual strength, it is determined in step S7 whether the sample 12 is in the state of the residual strength after the peak strength. If it is determined that the sample 12 is in the state of the residual strength, it ends, and the information of the detection means 20 is sent to the evaluation means 21 and evaluated. If it is determined in step S7 that the sample 12 is not in the state of the residual strength, the process proceeds to step S4 and the turning of the drive base 32 is continued (for example, it is continued until the state of the residual strength is reached).

[0096] As shown in Fig. 12, the shear stress with respect to the shear displacement changes from the state before shear (1) to the state before the peak strength is expressed (2), after the peak strength is expressed (3), and the state of the residual strength (4). In step S7, it is determined whether it is in the state of the residual strength (4). Therefore, the water permeability situation of the shear zone 17 in the state of the residual strength can be evaluated.

[0097] In addition, it is also possible to evaluate the water permeability situation of the shear zone 17 in any state such as before the peak strength is expressed (2) and after the peak strength is expressed (3).

[0098] As described above, by shearing the sample 12 due to the displacement generated in the rotation direction to reduce the displacement constraint, and passing pressurized water through a predetermined gap, water can be passed along the surface of the shear zone 17 with respect to the vicinity of the shear zone 17, and water can be passed with respect to the vicinity of the shear zone 17 while maintaining the restraint state of the sample 12.

[0099] Therefore, the sample 12 can be deformed and sheared until the state of the residual strength after the peak strength, displacement can be generated in the sample 12, water can be passed through the shear surface of the shear zone 17 without changing the state of the sample 12 after shear, the water permeability situation can be accurately evaluated by passing water through the shear zone 17, and the water permeability of the shear zone 17 of the sample 12 in any shear state (process) can be evaluated. That is, the water permeability of the shear zone 17 caused by the displacement due to the result of applying a shear force to the sample 12 can be evaluated.

[0100] That is, the water permeability in the shear state (process) in which the sample 12 is deformed until the state of the residual strength after the peak strength can be evaluated, and the change in water permeability accompanying the progress of shear can be evaluated.

[0101] In the above-described water permeability evaluation device 11, the water permeability of the shear zone 17 of the sample 12 in any shear state (process) can be evaluated.

Industrial Applicability

[0102] The present invention can be used in the industrial field of water permeability evaluation devices and water permeability evaluation methods.

Explanation of Reference Numerals

[0103] 1, 11 Water permeability evaluation device 2, 12 Specimen 3, 13 First holding member 4, 14 Second holding member 5, 17 Shear zone 6 Shearing means 7 Water supply means 8 Water supply detection means 9 Evaluation means 15 Pressurizing means 16 Rotational drive means 18 Lifting means 19 Water supply means 20 Detection means 21 Evaluation means 24 Water supply means 25 Downstream channel 26 Upstream channel 27 Discharge channel 28, 30, 62 Valve 31 Frame 32 Drive base 33 Base 34 Holding base 35 Lower holding part 36 Lower cylindrical part 37 Lower column part 38 Horizontal water passage 39 Vertical water passage 40 Porous member 41 Screw shaft 42 Nut member 43 Loading frame 44 Load cell 45 Lifting base 46 Pressing member 47 Notched cylindrical part 48 Pressing ring 49 Upper holding part 51 Upper frame member 52 Upper column part 53 Flange part 54 Upper cylindrical part 55 Flange 58 Ring flange 59 Drainage channel 61 Flow path 65 Position detection means 66 Sensor rod 67 Detection arm 71 Screw jack 72 Lifting plate 73 Connecting bar 74 Load detector 75 Gap detection means (dial gauge) 76 Detection unit

Claims

Claim 1 a first holding member for holding one side of the sample; a second holding member for holding the other side of the sample and constraining the sample between the first holding member; shearing means for relatively moving the first holding member and the second holding member to deform the sample and form a shear band in the sample; at least performing desired water flow on the constrained sample before forming a shear band in the sample, from directions along at least the one side and the other side, so that a shear band can be formed in a desired water flow direction during deformation, and after forming a desired water flow shear band in the sample, performing water flow in a direction along the surface on the shear band formed in the sample; water flow means; evaluation means for detecting the state of water flow by the water flow means and evaluating the water permeability situation of the shear band; A water permeability evaluation device, characterized in that it has the above. Claim 2 constraining the sample from both sides of a central axis; performing desired water flow on the constrained sample from a direction intersecting the central axis; after performing the desired water flow, displacing and shearing the sample so that a shear band can be formed in a direction along the desired water flow; evaluating the water permeability situation of the part including the shear surface by performing water flow in a direction along the shear band; A water permeability evaluation method, characterized in that it has the above. Claim 3 In the water permeability evaluation method according to Claim 2, the direction intersecting the central axis is a direction perpendicular to the central axis; A water permeability evaluation method, characterized in that it has the above. Claim ​ ​ ​

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