Soil material testing device and soil material testing method

Abstract

To provide a soil material testing device and a soil material testing method capable of enhancing accuracy of water conduction to a soil material while enhancing accuracy of testing.SOLUTION: A soil material testing device includes: a first syringe 11 capable of accommodating a soil material M; a first piston 12 capable of applying a pressure to the soil material M; a first measurement unit 15 including a first pressure measurement part 13 configured to measure the pressure applied to the soil material M by the first piston 12 and a first control part 14 configured to control a travel speed of the first piston 12; a second syringe 21 configured to house a water conduction liquid E; a second piston 22 capable of applying a pressure to the water conduction liquid E to supply the water conduction liquid E to the soil material M; and a second measurement unit 25 including a second pressure measurement part 23 configured to measure the pressure applied by the second piston 22 to the water conduction liquid E and a second control part 24 configured to control a travel speed of the second piston 22.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a soil material testing apparatus and a soil material testing method.

Background Art

[0002] Patent Document 1 describes a behavior evaluation test apparatus for a swelling material for evaluating the behavior of a material covering members such as waste in an environmental field of a disposal facility for radioactive waste, industrial waste, etc. The behavior evaluation test apparatus includes a base, and a pedestal that is placed on the base and has a load cell, bentonite which is a swelling material, and a hole into which a piston enters.

[0003] The bentonite is disposed above the load cell. A lower porous plate is disposed between the bentonite and the load cell, and an upper porous plate is disposed on the upper portion of the bentonite. The piston presses the bentonite through the upper porous plate. A non-contact displacement meter as displacement detection means is disposed on the lower surface of the upper porous plate, and the non-contact displacement meter is embedded in the bentonite. A detection portion detected by the non-contact displacement meter is provided on the upper surface of the lower porous plate. By the non-contact displacement meter detecting the detection portion, the gap amount from the non-contact displacement meter to the detection portion, that is, the vertical position (height) of the upper surface of the bentonite is detected.

[0004] A pair of support columns extending upward from the base are provided at the peripheral position of the pedestal on the base. An arm column is spanned between the pair of support columns, and pressing means having a piston is provided on the arm column. The pressing means has a drive portion which is a motor fixed to the arm column, and by driving the drive portion, the piston moves in the vertical direction and presses the upper porous plate and the bentonite into a predetermined state. The pedestal is detachable, and the pedestal can be pretreated with a salt, high pH, high temperature solution at another location or environmental conditions, and when water is supplied, the salt, high pH, high temperature solution can be passed through the bentonite to grasp the swelling characteristics, swelling pressure, and swelling deformation amount of the bentonite.

[0005] A water supply line is connected to the lower perforated plate, and a drainage line is connected to the upper perforated plate. By supplying water from the water supply line with bentonite sandwiched between the lower perforated plate and the upper perforated plate, water is evenly sent to the bentonite from the bottom surface, causing the bentonite to swell, and the excess water is discharged from the drainage line.

[0006] The drive part of the pressing means and the like are driven based on the instruction signal of the control device. Detection information of the load cell and detection information of the non-contact displacement meter are input to the control device. And the control device stores information on the physical properties of rock masses and the like, which is the surrounding environment where the bentonite is placed. A predetermined amount of water is supplied to the bentonite, the swelling pressure (displacement pressure) is detected by the load cell, and the displacement amount of the bentonite corresponding to the pressure change is obtained based on the physical properties of the rock mass and the like. Then, the pressing means operates so that the bentonite is displaced to a state that matches the displacement amount. In this way, the displacement amount of the bentonite with respect to the pressure change is reproduced in a form corresponding to the displacement amount of the rock mass and the like.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] By the way, since the swelling amount test for measuring the swelling amount of the soil material and the swelling pressure test for measuring the swelling pressure of the soil material are not standardized tests, various soil material test apparatuses are used, and there is a current situation where test results vary. When evaluating the swelling deformation amount of the soil material, the weight of the piston installed to evaluate the deformation amount may have a great influence on the test results. Also, as described above, it is necessary to conduct water flow through the soil material. However, regarding the water flow through the soil material, higher accuracy is required. Furthermore, it is required to improve the accuracy of various tests of the soil material.

[0009] The present disclosure aims to provide a soil material testing apparatus and a soil material testing method that can improve the accuracy of water flow through soil materials and enhance the accuracy of tests.

Means for Solving the Problems

[0010] (1) The soil material testing apparatus according to the present disclosure is a soil material testing apparatus for testing the water absorption and swelling characteristics of soil materials. The soil material testing apparatus includes a first syringe into which the soil material is placed, a first piston capable of applying pressure to the soil material placed in the first syringe inside the first syringe, a first pressure measurement unit for measuring the pressure applied by the first piston to the soil material, and a first measurement unit having a first control unit for controlling the moving speed of the first piston, a second syringe for storing the aqueous solution supplied to the soil material inside the first syringe, a second piston capable of supplying the aqueous solution to the soil material by applying pressure to the aqueous solution placed in the second syringe inside the second syringe, a second pressure measurement unit for measuring the pressure applied by the second piston to the aqueous solution, and a second measurement unit having a second control unit for controlling the moving speed of the second piston.

[0011] In this soil material testing device, the soil material is placed in the first syringe, and the soil material can be pressurized by the first piston. The first measurement unit includes a first pressure measurement unit that measures the pressure applied by the first piston to the soil material, and a first control unit that controls the moving speed of the first piston. By having the first pressure measurement unit in the first measurement unit, the deformation amount and pressure applied to the soil material can be measured with high precision. The soil material testing device has a second syringe that houses the aqueous solution for supplying to the soil material, and a second piston that can pressurize the aqueous solution housed in the second syringe. Further, the soil material testing device has a second measurement unit. The second measurement unit includes a second pressure measurement unit that measures the pressure applied by the second piston to the aqueous solution, and a second control unit that controls the moving speed of the second piston. By the second control unit controlling the moving speed of the second piston, the flow rate of the aqueous solution to the soil material can be controlled with high precision. By the second control unit controlling the moving speed of the second piston according to the measurement result of the first pressure control unit or the measurement result of the second pressure control unit, the water injection pressure to the soil material can be controlled with high precision. Further, by the second control unit stopping the second piston and the first piston pressurizing the aqueous solution, a swelling pressure test and a water permeability test of the soil material can be performed. Therefore, the accuracy of water injection to the soil material is improved to enhance the test accuracy, and various tests can be executed using this soil material testing device.

[0012] (2) In the above (1), the first syringe and the second syringe may be made of a corrosion-resistant material. In this case, the corrosion resistance of the first syringe that houses the soil material and the second syringe that houses the aqueous solution can be enhanced. Therefore, it is possible to suppress the decrease in test accuracy due to corrosion.

[0013] (3) In the above (1) or (2), the first control unit may include a first ball screw with a screw shaft connected to the first piston and a first pulse motor for driving the first ball screw, and the second control unit may include a second ball screw with a screw shaft connected to the second piston and a second pulse motor for driving the second ball screw. In this case, in each of the first control unit and the second control unit, the pulse motor controls the driving of the ball screw, causing the first piston and the second piston to move respectively. Therefore, the movement of the first piston and the second piston can be performed with higher precision, contributing to further improvement of the test accuracy.

[0014] (4) In any of the above (1) to (3), the soil material testing device may include a pipe disposed below the first syringe and the second syringe and having a space communicating with both the internal space of the first syringe and the internal space of the second syringe, and a valve disposed in the pipe. The aqueous solution introduced into the second syringe may be supplied to the soil material inside the first syringe through the pipe. In this case, the aqueous solution can be supplied to the soil material through the pipe located below the first syringe and the second syringe, so that the air in the soil material can be smoothly exhausted. Furthermore, since a valve is provided in the pipe, the aqueous solution can be controlled by the valve.

[0015] (5) In any of the above (1) to (4), the first piston and the first measurement unit may have a space communicating with the internal space of the first syringe. The gas and liquid in the internal space of the first syringe may be discharged to the outside of the soil material testing device through the space of the first piston and the space of the first measurement unit. In this case, the gas and liquid can be discharged from the internal space of the first syringe to the outside of the soil material testing device.

[0016] (6) In any one of (1) to (5) above, the first measurement unit may have a first displacement measurement unit that measures the displacement of the first piston. In this case, since the displacement of the first piston can be measured by the first displacement measurement unit, the movement control of the first piston capable of pressurizing the soil material can be performed with higher accuracy.

[0017] (7) The soil material test method according to the present disclosure is a soil material test method for testing the water absorption and swelling characteristics of a soil material. The soil material test method includes a step of putting the soil material into a first syringe, a step of putting an aqueous solution for supplying the soil material into a second syringe, a step of supplying the aqueous solution to the soil material by applying pressure to the aqueous solution in the second syringe by a second piston, a step of measuring the pressure applied by the second piston to the aqueous solution, and a step of controlling the moving speed of the second piston.

[0018] In this soil material test method, the soil material is put into the first syringe, and the aqueous solution for supplying the soil material is accommodated in the second syringe. The aqueous solution accommodated in the second syringe is supplied to the soil material inside the first syringe by being pressurized by the second piston. In the soil material test method, the pressure applied by the second piston to the aqueous solution can be measured, and the moving speed of the second piston can be controlled. By controlling the moving speed of the second piston, the flow rate of the aqueous solution to the soil material can be controlled with high accuracy. Further, by controlling the moving speed of the second piston according to the pressure applied to the aqueous solution, the water pressure to the soil material can be controlled with high accuracy. Therefore, in the soil material test method, similar to the soil material test apparatus, the accuracy of water passing through the soil material can be improved to improve the test accuracy, and various tests can be executed.

[0019] (8) In the above (7), the step of putting the soil material into the first syringe may include the step of putting a sample serving as the basis of the soil material into the first syringe, and the step of the first piston pressurizing the sample put into the first syringe to produce the soil material. In this case, the soil material can be produced inside the first syringe, and the test of the soil material can be performed immediately thereafter. Therefore, it is possible to suppress the occurrence of a gap between the inner wall of the piston and the soil material that greatly affects the test result, and it is also possible to improve the efficiency of the test of the soil material.

Effect of the Invention

[0020] According to the present disclosure, it is possible to improve the accuracy of water flow into the soil material and also improve the accuracy of the test.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of a soil material test device and a soil material test method according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate. Also, the drawings may be drawn with some parts simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those described in the drawings.

[0023] FIG. 1 is a diagram showing a soil material test device 1 according to an embodiment. First, an example of the soil material M to be tested by the soil material test device 1 will be described. For example, the soil material M is an expansive soil that swells by absorbing water. The soil material M is, for example, a specimen produced by compression molding of soil. As an example, the soil material M is bentonite. The soil material test device 1 performs a test for evaluating the swelling characteristics of the soil material M.

[0024] Examples of tests for evaluating swelling characteristics include a swelling amount test and a swelling pressure test. The swelling amount test is a test for measuring the swelling amount (e.g., upward swelling amount) that occurs when the soil material M absorbs water. The swelling pressure test is a test for measuring the pressure that occurs when the soil material M is supplied with water under volume restraint conditions. In the soil material testing apparatus 1, the test that allows deformation of the soil material M is the swelling amount test, and the test that does not allow deformation of the soil material M is the swelling pressure test.

[0025] The swelling amount test and the swelling pressure test have been carried out by many test institutions so far, and test data has been accumulated. However, since the swelling amount test and the swelling pressure test are not standardized tests, differences can be seen in the structure of the test apparatus and the test method for each test institution, and there is a current situation where these are affecting the measurement results.

[0026] In the swelling amount test, the specimen to be tested swells mechanically until the self-weight of the specimen and the swelling pressure balance out. At this time, the swelling amount is often measured through a piston installed on the specimen. It can be said that the influence of the weight of the piston on the test results is significant for a very small stress balance state where the self-weight of the specimen and the swelling pressure balance out. Also, if the piston becomes eccentric during the test, the piston may engage with the inner wall of the test cell. In this case, the movement of the piston is restricted, and it may be difficult to measure the swelling amount.

[0027] Water may be passed through the specimen using a burette, but it is possible that the swelling behavior changes as the water level in the burette changes. When the hydrodynamic gradient of the burette becomes small, the amount of water passed through the specimen decreases. Therefore, when the swelling state reaches an equilibrium state and the water supply burette is replaced (the water level difference increases), the swelling behavior may resume. Thus, a problem may occur where the swelling behavior is affected by the occurrence of a water level difference in the burette.

[0028] In the soil material testing apparatus 1 according to the present embodiment, it is possible to suppress the occurrence of the above problems. Hereinafter, the details of the soil material testing apparatus 1 will be described. The soil material testing apparatus 1 is an apparatus for testing the water absorption and swelling characteristics of the soil material M. The soil material M is, for example, clay that covers a metal container in which radioactive waste is enclosed, and the metal container covered with the clay is buried in a disposal hole in a rock formation more than 300 m deep from the ground surface. Since the outer diameter of the clay is smaller than the inner diameter of the disposal hole, the clay is required to have high expansibility, adsorption ability, and water stoppage ability. For example, the soil material testing apparatus 1 measures the expansibility, adsorption ability, and water stoppage ability of the clay.

[0029] The soil material testing apparatus 1 includes a support mechanism 2, a first unit 10 in which the characteristics of the soil material M are measured, and a second unit 20 that stores the aqueous solution E supplied to the soil material M. The aqueous solution E is, for example, water containing salts. The aqueous solution E may be artificial seawater. The aqueous solution E may be a calcium chloride solution or a magnesium chloride solution.

[0030] The support mechanism 2 supports the first unit 10 and the second unit 20. For example, the height of the first unit 10 is the same as the height of the second unit 20. The support mechanism 2 includes a first lower member 3b on which the first unit 10 is placed, a first upper member 3c located above the first unit 10, a second lower member 4b on which the second unit 20 is placed, and a second upper member 4c located above the second unit 20. The support mechanism 2 includes a plurality of first rod-shaped members 5 that support the first upper member 3c above the first lower member 3b, and a plurality of second rod-shaped members 6 that support the second upper member 4c above the second lower member 4b.

[0031] The first lower member 3b, the first upper member 3c, the second lower member 4b, and the second upper member 4c are, for example, reaction plates. For example, the first lower member 3b, the first upper member 3c, the second lower member 4b, and the second upper member 4c are plate-shaped. In this case, the first lower member 3b, the first upper member 3c, the second lower member 4b, and the second upper member 4c extend in a first direction D1 and a second direction D2 that intersects the first direction D1, and have a thickness in a third direction D3 that intersects both the first direction D1 and the second direction D2.

[0032] The first direction D1 is a horizontal direction and is the direction in which the first unit 10 and the second unit 20 are arranged. The second direction D2 is a horizontal direction and is a direction orthogonal to the first direction D1. The third direction D3 is a vertical direction. As an example, the shapes of the first lower member 3b, the first upper member 3c, the second lower member 4b, and the second upper member 4c in a plan view (when viewed along the third direction D3) are rectangular. However, the shapes of the first lower member 3b, the first upper member 3c, the second lower member 4b, and the second upper member 4c are not particularly limited.

[0033] For example, the first rod-shaped member 5 and the second rod-shaped member 6 are tie rods. The first lower member 3b, the first upper member 3c, the second lower member 4b, and the second upper member 4c have through holes 7 that penetrate in the plate thickness direction (the third direction D3). Each of the first rod-shaped member 5 and the second rod-shaped member 6 is passed through the through hole 7.

[0034] As an example, the soil material testing device 1 includes four first rod-shaped members 5, and the first rod-shaped members 5 are arranged at the four corners of the first lower member 3b and the first upper member 3c in a plan view. For example, the soil material testing device 1 includes four second rod-shaped members 6, and the second rod-shaped members 6 are arranged at the four corners of the second lower member 4b and the second upper member 4c in a plan view. However, the number and arrangement modes of the first rod-shaped member 5 and the second rod-shaped member 6 are not limited to the above examples.

[0035] The first rod-shaped member 5 has a head 5b that contacts the upper surface of the first upper member 3c and a threaded portion into which the nut 8 is screwed. For example, three nuts 8 are screwed onto one first rod-shaped member 5. One of the three nuts 8, together with the head 5b of the first rod-shaped member 5, clamps the first upper member 3c, and the remaining two sandwich and clamp the first lower member 3b. The first rod-shaped member 5 protrudes downward from the first lower member 3b, and the lower end of the first rod-shaped member 5 is in contact with the floor surface or the like. The second rod-shaped member 6, like the first rod-shaped member 5, has a head 6b and a threaded portion into which the nut 8 is screwed. Since the structures of the second rod-shaped member 6 and the nut 8 are the same as those of the first rod-shaped member 5 and the nut 8 described above, the description thereof is omitted.

[0036] The soil material testing device 1 has, for example, a pipe 30 for transferring the passing aqueous solution E of the second unit 20 to the soil material M, and a storage portion 40 for storing the passing aqueous solution E supplied to the second unit 20 via the pipe 30. The pipe 30 is a pipe for supplying the passing aqueous solution E to either the first unit 10 or the second unit 20. For example, the pipe 30 extends in the first direction D1 below the first lower member 3b and the second lower member 4b.

[0037] The pipe 30 is made of a material having corrosion resistance. As an example, the material of the pipe 30 is stainless steel. However, the material of the pipe 30 does not have to be stainless steel, and may be, for example, a metal-based material such as titanium, SUS, or a nickel-based alloy. Thus, the material of the pipe 30 can be changed as appropriate.

[0038] For example, the pipe 30 has an extending portion 31 extending from the storage portion 40, a first pipe portion 32 extending from the extending portion 31 to the first unit 10, and a second pipe portion 33 extending from the extending portion 31 to the second unit 20. The first pipe portion 32 and the second pipe portion 33 are portions branched from the extending portion 31. The pipe 30 has a discharge port 34 at the end opposite to the storage portion 40.

[0039] The first lower member 3b has a hole 3d that penetrates the first lower member 3b in the third direction D3 below the first unit 10, and the first pipe portion 32 is passed through the hole 3d and connected to the first unit 10. The second lower member 4b has a hole 4d that penetrates the second lower member 4b in the third direction D3 below the second unit 20, and the second pipe portion 33 is passed through the hole 4d and connected to the second unit 20.

[0040] For example, the soil material testing device 1 has a valve 35 disposed in the pipe 30. The valve 35 may be a manual valve or an automatic valve, and the type of the valve 35 is not particularly limited. As an example, the valve 35 is a solenoid valve. The soil material testing device 1 has, for example, a plurality of valves 35. The valves 35 are provided in each of the first pipe portion 32 and the second pipe portion 33. By opening and closing the valve 35 provided in the first pipe portion 32, the control of the aqueous solution E flowing through to the first unit 10 is possible, and by opening and closing the valve 35 provided in the second pipe portion 33, the control of the aqueous solution E flowing through to the second unit 20 is possible.

[0041] The storage portion 40 is provided to store the aqueous solution E in advance. The aqueous solution E stored in the storage portion 40 is passed through the pipe 30 and discharged from the discharge port 34 before the test of the soil material M is started. Thereby, the air inside the pipe 30 is discharged, and the inside of the pipe 30 is made to contain only the aqueous solution E.

[0042] The first unit 10 has a first syringe 11 into which the soil material M is placed, a first piston 12 capable of applying pressure to the soil material M, and a first measurement unit 15 for measuring the water absorption and expansion characteristics of the soil material M. The second unit 20 has a second syringe 21 into which the aqueous solution E is placed, a second piston 22 capable of applying pressure to the aqueous solution E, and a second measurement unit 25 for controlling the movement of the second piston 22.

[0043] For example, the first syringe 11 and the second syringe 21 are cylindrical. By changing the cross-sectional area in a cross-section orthogonal to the longitudinal direction of the first syringe 11 and the second syringe 21, the control accuracy of the swelling amount and the water permeability can be improved. A pipe 30 is disposed below the first syringe 11 and the second syringe 21, and the pipe 30 has a space 30b that communicates with both the internal space 11b of the first syringe 11 and the internal space 21b of the second syringe 21. The aqueous solution E contained in the second syringe 21 is supplied to the soil material M inside the first syringe 11 through the pipe 30.

[0044] The first syringe 11 and the second syringe 21 are made of a corrosion-resistant material. As an example, the materials of the first syringe 11 and the second syringe 21 are stainless steel. However, the materials of the first syringe 11 and the second syringe 21 do not have to be stainless steel. For example, they may be metal-based materials such as titanium, SUS, or nickel-based alloys, or resin-based materials such as acrylic, polycarbonate, or MC nylon (registered trademark). Thus, the materials of the first syringe 11 and the second syringe 21 can be changed as appropriate.

[0045] The first syringe 11 has a bottom 11d in which a through-hole 11c penetrating the first syringe 11 in the third direction D3 is formed. The through-hole 11c communicates with the space 30b of the pipe 30 (the first pipe portion 32). The first piston 12 can apply pressure to the soil material M accommodated in the first syringe 11 inside the first syringe 11. For example, the first piston 12 has a rod 12b and is connected to the first measurement unit 15 via the rod 12b. The first unit 10 has a plurality of O-rings 17 provided on the outer surface of the first piston 12 and sliding on the inner surface of the first syringe 11.

[0046] The first piston 12 has a plurality of recesses 12c that are recessed inside the first piston 12 in a plan view, and an O-ring 17 is inserted into each of the plurality of recesses 12c. The plurality of O-rings 17 are arranged along the direction (third direction D3) in which the first piston 12 moves. By arranging the plurality of O-rings 17 in this way, the water-stopping property of the first piston 12 can be enhanced and the movement of the first piston 12 can be stabilized. Furthermore, the eccentricity of the first piston 12 can be suppressed, and the first piston 12 can be prevented from moving eccentrically. Instead of the plurality of O-rings 17, a guide rail or a bearing may be arranged. In this case, the first piston 12 can be moved more smoothly.

[0047] The first unit 10 has an upper porous plate 18b located between the soil material M and the first piston 12, and a lower porous plate 18c located between the soil material M and the bottom 11d of the first syringe 11. The soil material M is arranged between the upper porous plate 18b and the lower porous plate 18c, and the passing aqueous solution E that has passed through the lower porous plate 18c from the first pipe portion 32 is supplied to the soil material M. Thereby, since the passing aqueous solution E that has passed through the numerous holes of the lower porous plate 18c is supplied to the soil material M, the passing aqueous solution E can be uniformly supplied to the soil material M.

[0048] The first measurement unit 15 has a first pressure measurement unit 13 that measures the pressure applied by the first piston 12 to the soil material M, and a first control unit 14 that controls the moving speed of the first piston 12. For example, the first measurement unit 15 has a first displacement measurement unit 19 that measures the displacement of the first piston 12.

[0049] For example, the first pressure measurement unit 13 is a pressure gauge built into the first measurement unit 15, and the first displacement measurement unit 19 is a displacement gauge built into the first measurement unit 15. In this way, the first measurement unit 15 incorporates a plurality of measuring instruments. For example, the first control unit 14 includes a first ball screw 14c with a screw shaft 14b connected to the first piston 12, and a first pulse motor 14d that drives the first ball screw 14c.

[0050] For example, the first measurement unit 15 has a housing 15b, and a plurality of measuring instruments (the first pressure measurement unit 13 and the first displacement measurement unit 19) and a first pulse motor 14d are built into the housing 15b. In this way, in the first measurement unit 15, since a plurality of measuring instruments and the first pulse motor 14d are built in, compactification can be achieved. Further, by driving the first ball screw 14c by the first pulse motor 14d, the movement of the first piston 12 can be performed with high precision.

[0051] The first ball screw 14c has a screw shaft 14b extending from the housing 15b toward the first piston 12 and a screw shaft 14f extending upward from the housing 15b. For example, the first upper member 3c has a through hole 3f penetrating the first upper member 3c in the third direction D3, and the screw shaft 14f penetrates the through hole 3f and protrudes upward from the first upper member 3c.

[0052] When the first pulse motor 14d drives the first ball screw 14c, the screw shaft 14f rotates, and the rotational motion of the screw shaft 14f is converted into a linear motion, causing the screw shaft 14b and the first piston 12 to move up and down. Thereby, the first piston 12 can be moved up and down with high precision. By using the screw shafts 14b and 14f with a fine thread pitch, the up and down movement of the first piston 12 becomes more precise.

[0053] The first piston 12 and the first measurement unit 15 have a space S communicating with the internal space 11b of the first syringe 11 (the space in which the soil material M is accommodated). The space S is formed inside the first piston 12, inside the rod 12b, inside the screw shaft 14b, inside the housing 15b, and inside the screw shaft 14f. That is, the first piston 12, the rod 12b, the screw shaft 14b, the housing 15b, and the screw shaft 14f are hollow. For example, the gas and liquid in the internal space 11b of the first syringe 11 can be discharged to the outside of the soil material testing device 1 through the space S of the first piston 12, the space S of the rod 12b, and the space S of the first measurement unit 15.

[0054] For example, the soil material testing apparatus 1 has a terminal T connected to the first measurement unit 15. As an example, the terminal T is connected to the first measurement unit 15 via a cable B1. For example, the pressure by the first piston 12 measured by the first pressure measurement unit 13 and the displacement of the first piston 12 measured by the first displacement measurement unit 19 are output to the terminal T.

[0055] The second syringe 21 stores the passing aqueous solution E supplied to the soil material M inside the first syringe 11. The second syringe 21 has a bottom portion 21d in which a through hole 21c penetrating the second syringe 21 in the third direction D3 is formed. The through hole 21c communicates with the space 30b of the pipe 30 (second pipe portion 33).

[0056] The second piston 22 can supply the passing aqueous solution E to the soil material M by applying pressure to the passing aqueous solution E placed in the second syringe 21 inside the second syringe 21. The second piston 22 can apply pressure to the passing aqueous solution E stored in the second syringe 21 inside the second syringe 21. For example, the second piston 22 has a rod 22b and is connected to the second measurement unit 25 via the rod 22b.

[0057] The second unit 20 has a plurality of O-rings 27 provided on the outer surface of the second piston 22 and sliding on the inner surface of the second syringe 21. The second piston 22 has a plurality of recesses 22c recessed inside the second piston 22 in plan view, and the O-rings 27 are inserted into each of the plurality of recesses 22c.

[0058] The plurality of O-rings 27 are arranged along the direction (the third direction D3) in which the second piston 22 moves. By arranging the O-rings 27 in this way, similar to the O-rings 17 described above, the water-stopping property of the second piston 22 can be enhanced, and the eccentricity of the second piston 22 can be suppressed to stabilize the movement of the second piston 22. And, similar to the case of the O-ring 17, a guide rail or a bearing may be arranged instead of the plurality of O-rings 27. For example, the second unit 20 has a porous plate 28 located between the aqueous solution E and the bottom 21d of the second syringe 21. Note that the porous plate 28 may be omitted.

[0059] The second measurement unit 25 has a second pressure measurement unit 23 that measures the pressure applied by the second piston 22 to the aqueous solution E, and a second control unit 24 that controls the moving speed of the second piston 22. The second measurement unit 25 may have a second displacement measurement unit 29 that measures the displacement of the second piston 22.

[0060] The second pressure measurement unit 23 may be a pressure gauge built in the second measurement unit 25, and the second displacement measurement unit 29 may be a displacement gauge built in the second measurement unit 25. For example, the second unit 20, similar to the first unit 10, incorporates a plurality of measuring instruments. The second control unit 24, similar to the first control unit 14 described above, includes a second ball screw 24c with a screw shaft 24b connected to the second piston 22, and a second pulse motor 24d that drives the second ball screw 24c.

[0061] For example, the second measurement unit 25 has a housing 25b, and a plurality of measuring instruments (the second pressure measurement unit 23 and the second displacement measurement unit 29) and the second pulse motor 24d are built in the housing 25b. Therefore, in the second measurement unit 25, similar to the first measurement unit 15 described above, compactification can be achieved, and the movement of the second piston 22 can be performed with high precision.

[0062] The second ball screw 24c has a screw shaft 24b extending from the housing 25b toward the second piston 22 and a screw shaft 24f extending upward from the housing 25b. The second upper member 4c has, for example, a through hole 4f penetrating the second upper member 4c in the third direction D3, and the screw shaft 24f penetrates the through hole 4f and protrudes upward from the second upper member 4c.

[0063] When the second pulse motor 24d drives the second ball screw 24c, the screw shaft 24f rotates, and the rotational motion of the screw shaft 24f is converted into linear motion, causing the screw shaft 24b and the second piston 22 to move up and down. Therefore, in the second piston 22 and the second measurement unit 25, similar to the first piston 12 and the first measurement unit 15 described above, the second piston 22 can be moved up and down with high precision, and by using the screw shafts 24b and 24f with a fine pitch of the screw thread, the up and down movement of the second piston 22 becomes even more precise.

[0064] The second piston 22 and the second measurement unit 25 are different from the first piston 12 and the first measurement unit 15 described above in that they do not have the space S described above. However, some configurations of the second unit 20 are the same as some configurations of the first unit 10. Specifically, the second syringe 21 can be the same as the first syringe 11, the second pressure measurement unit 23 can be the same as the first pressure measurement unit 13, and the second pulse motor 24d can be the same as the first pulse motor 14d. Therefore, the configuration of the soil material testing device 1 can be simplified.

[0065] The terminal T is connected to, for example, the second measurement unit 25. As an example, the terminal T is connected to the second measurement unit 25 via a cable B2. For example, the pressure by the second piston 22 measured by the second pressure measurement unit 23 and the displacement of the second piston 22 measured by the second displacement measurement unit 29 are output to the terminal T.

[0066] The terminal T may be able to set the water flow pressure and water flow rate to the aqueous solution E by the second piston 22. Further, in the terminal T, the pressure on the soil material M by the first piston 12 may be settable, and the moving speed of the first piston 12 may be settable. In this case, according to the content set in the terminal T, each part of the first measurement unit 15 and each part of the second measurement unit 25 operate to move the first piston 12 and the second piston 22 with high precision.

[0067] Next, an example of the steps of the soil material test method according to the embodiment will be described with reference to the flowchart of FIG. 2. In the soil material test method, for example, the water absorption and swelling characteristics of the soil material M are tested using the soil material test apparatus 1. First, for example, the soil material M is prepared, and the prepared soil material M is put into the first syringe 11 (step of putting the soil material into the first syringe).

[0068] Specifically, for example, a sample serving as the basis of the soil material M is put into the first syringe 11 (step of putting the sample into the first syringe, step S1). Then, the first piston 12 pressurizes the sample placed in the first syringe 11 to prepare the soil material M (step of preparing the soil material M, step S2).

[0069] On the other hand, the aqueous solution E is put into the storage unit 40, the valves 35 connected to the first pipe portion 32 and the second pipe portion 33 are closed, and the air in the pipe 30 is removed by flowing the aqueous solution E from the pipe 30 to the discharge port 34 (step of removing air from the pipe, step S4). Further, by opening the valve 35 connected to the second pipe portion 33, the aqueous solution E stored in the storage unit 40 is put into the second syringe 21 (step of putting the aqueous solution into the second syringe, step S3).

[0070] For example, the terminal T sets the water flow pressure, water flow rate by the second piston 22, the overlying pressure by the first piston 12, and the moving speed of the first piston 12 (the step of setting pressure and flow rate, step S5). As a specific example, when performing a swelling amount test of the soil material M, the pressure applied to the soil material M by the first piston 12 is set to 0, and when performing a swelling pressure test or a water permeability test of the soil material M, the moving speed of the first piston 12 is set to 0 and the position of the first piston 12 is fixed.

[0071] After step S5, the second piston 22 applies pressure to the aqueous solution E to supply the aqueous solution E to the soil material M (the step of supplying the aqueous solution to the soil material, step S6). At this time, the second pressure measurement unit 23 measures the pressure applied by the second piston 22 to the aqueous solution E, and the second control unit 24 controls the movement of the second piston 22 to control the water flow pressure and water flow rate by the first piston 12 (the step of controlling the water flow pressure and water flow rate).

[0072] Then, the soil material M is measured (the step of measuring the soil material, step S7). Specifically, when performing a swelling amount test of the soil material M, the soil material M is expanded without applying pressure by water flow. When performing a swelling pressure test of the soil material M, the second pressure measurement unit 23 measures the pressure of the soil material M through which water has flowed with the first piston 12 fixed. When performing a water permeability test of the soil material M, the amount of water discharged from the soil material M to the outside of the soil material testing device 1 through the space S with the first piston 12 fixed is measured. As described above, after the measurement of the soil material M is completed, a series of steps of the soil material test method are completed.

[0073] Next, the operation and effects of the soil material testing apparatus 1 and the soil material testing method according to the present embodiment will be described in detail. In the soil material testing apparatus 1 and the soil material testing method according to the present embodiment, a soil material M is placed in a first syringe 11, and the soil material M can be pressurized by a first piston 12. The first measurement unit 15 includes a first pressure measurement unit 13 that measures the pressure applied by the first piston 12 to the soil material M, and a first control unit 14 that controls the moving speed of the first piston 12. Since the first measurement unit 15 has the first pressure measurement unit 13, the deformation amount and pressure applied to the soil material M can be measured with high precision.

[0074] The soil material testing apparatus 1 includes a second syringe 21 that stores a through aqueous solution E for supplying the soil material M, and a second piston 22 that can pressurize the through aqueous solution E stored in the second syringe 21. Further, the soil material testing apparatus 1 has a second measurement unit 25. The second measurement unit 25 includes a second pressure measurement unit 23 that measures the pressure applied by the second piston 22 to the through aqueous solution E, and a second control unit 24 that controls the moving speed of the second piston 22. By the second control unit 24 controlling the moving speed of the second piston 22, the flow rate (through water flow rate) of the through aqueous solution E to the soil material M can be controlled with high precision.

[0075] By the second control unit 24 controlling the moving speed of the second piston 22 according to the measurement result of the first pressure measurement unit 13 or the measurement result of the second pressure measurement unit 23, the pressure applied to the soil material M can be controlled with high precision. Further, by the first control unit 14 stopping the first piston 12 and the second piston 22 supplying the through aqueous solution E to the soil material M, a swelling pressure test and a water permeability test of the soil material M can be performed. Therefore, the accuracy of water flow to the soil material M is improved to enhance the test accuracy, and various tests can be executed using the soil material testing apparatus 1.

[0076] In this embodiment, the first syringe 11 and the second syringe 21 may be made of a corrosion-resistant material. In this case, the corrosion resistance of the first syringe 11 that houses the soil material M and the second syringe 21 that houses the aqueous solution E can be enhanced. Therefore, it is possible to prevent the accuracy of the test from deteriorating due to corrosion. As described above, the pipe 30 may be made of a corrosion-resistant material. In this case, the above effects become more prominent.

[0077] In this embodiment, the first control unit 14 includes a first ball screw 14c whose screw shaft 14b is connected to the first piston 12, and a first pulse motor 14d that drives the first ball screw 14c. The second control unit 24 includes a second ball screw 24c whose screw shaft 24b is connected to the second piston 22, and a second pulse motor 24d that drives the second ball screw 24c. In this case, in each of the first control unit 14 and the second control unit 24, the pulse motor controls the drive of the ball screw, whereby the first piston 12 and the second piston 22 move respectively. Therefore, the movement of the first piston 12 and the second piston 22 can be performed with higher precision, contributing to further improvement of the test accuracy.

[0078] In this embodiment, the soil material testing device 1 includes a pipe 30 that is disposed below the first syringe 11 and the second syringe 21 and has a space 30b that communicates with both the internal space 11b of the first syringe 11 and the internal space 21b of the second syringe 21, and a valve 35 disposed in the pipe 30. The aqueous solution E placed in the second syringe 21 is supplied to the soil material M inside the first syringe 11 through the pipe 30. In this case, since the aqueous solution E can be supplied to the soil material M through the pipe 30 located below the first syringe 11 and the second syringe 21, the air in the soil material M can be smoothly exhausted. Further, since the valve 35 is provided in the pipe 30, the aqueous solution E can be controlled by the valve 35.

[0079] In this embodiment, the first piston 12 and the first measurement unit 15 have a space S communicating with the internal space 11b of the first syringe 11. The gas and liquid in the internal space 11b of the first syringe 11 can be discharged to the outside of the soil material testing device 1 through the space S of the first piston 12 and the space S of the first measurement unit 15. In this case, the gas and liquid can be discharged from the internal space 11b of the first syringe 11 to the outside of the soil material testing device 1. For example, during the permeability test of the soil material M, drainage can be performed from the soil material M to the outside of the soil material testing device 1.

[0080] In this embodiment, the first measurement unit 15 has a first displacement measurement unit 19 that measures the displacement of the first piston 12. In this case, since the displacement of the first piston 12 can be measured by the first displacement measurement unit 19, the movement control of the first piston 12 capable of pressurizing the soil material M can be performed with higher precision.

[0081] In the soil material testing method according to this embodiment, the step of putting the soil material M into the first syringe 11 includes the step of putting the sample serving as the basis of the soil material M into the first syringe 11 and the step of the first piston 12 pressurizing the sample put into the first syringe 11 to produce the soil material M. In this case, the soil material M as the specimen can be produced inside the first syringe 11, and the test of the soil material M can be performed immediately thereafter. Therefore, the generation of the gap between the piston inner wall and the soil material M, which has a great influence on the test results, can be suppressed, and the efficiency of the test of the soil material M can also be improved.

[0082] As described above, embodiments of the soil material testing device and the soil material testing method according to the present disclosure have been described. However, the soil material testing device and the soil material testing method according to the present disclosure are not limited to the content of the foregoing embodiments, and may be further modified within the scope of the gist described in the claims. That is, the shape, size, material, number, and arrangement mode of each part of the soil material testing device, as well as the content and order of the steps of the soil material testing method, can be appropriately changed within the scope of the above gist.

[0083] For example, in the above-described embodiment, the first unit 10 having the first ball screw 14c and the first pulse motor 14d was described. However, the first unit 10 may have a syringe pump instead of the first ball screw 14c and the first pulse motor 14d. Thus, the type of device constituting the first unit 10 can be appropriately changed. The same applies to the second unit 20.

[0084] For example, in the above-described embodiment, an example of testing the soil material M, which is clay covering a metal container encapsulating radioactive waste, was described. However, the soil material M may be a soil material used for general civil engineering purposes, and the type of the soil material M is not particularly limited. Thus, with the soil material testing apparatus and the soil material testing method according to the present disclosure, various tests can be performed on various soil materials.

Description of Reference Numerals

[0085] 1... Soil material testing device, 2... Support mechanism, 3b... First lower member, 3c... First upper member, 3d... Hole, 3f... Through hole, 4b... Second lower member, 4c... Second upper member, 4d... Hole, 4f... Through hole, 5... First rod-shaped member, 5b... Head, 6... Second rod-shaped member, 6b... Head, 7... Through hole, 8... Nut, 10... First unit, 11... First syringe, 11b... Internal space, 11c... Through hole, 11d... Bottom, 12... First piston, 12b... Rod, 12c... Recess, 13... First pressure measurement unit, 14... First control unit, 14b... Screw shaft, 14c... First ball screw, 14d... First pulse motor, 14f... Screw shaft, 15... First measurement unit, 15b... Housing, 17... O-ring, 18b... Upper porous plate, 18c... Lower porous plate, 19... First displacement measurement unit, 20... Second unit, 21... Second syringe, 21b... Internal space, 21c... Through hole, 21d... Bottom, 22... Second piston, 22b... Rod, 22c... Recess, 23... Second pressure measurement unit, 24... Second control unit, 24b... Screw shaft, 24c... Second ball screw, 24d... Second pulse motor, 24f... Screw shaft, 25... Second measurement unit, 25b... Housing, 27... O-ring, 28... Porous plate, 29... Second displacement measurement unit, 30... Pipe, 30b... Space, 31... Extension portion, 32... First pipe portion, 33... Second pipe portion, 34... Outlet, 35... Valve, 40... Storage portion, B1... Cable, B2... Cable, D1... First direction, D2... Second direction, D3... Third direction, E... Aqueous solution, M... Soil material, S... Space, S4... Step, T... Terminal.

Claims

1. A soil material testing device for testing the water absorption and expansion characteristics of a soil material, comprising: a first syringe into which the soil material is placed; a first piston within the first syringe capable of applying pressure to the soil material contained in the first syringe; a first measuring unit having a first pressure measuring unit that measures the pressure that the first piston is applying to the soil material and a first control unit that controls the moving speed of the first piston; a second syringe containing a water solution to be supplied to the soil material inside the first syringe; a second piston in the second syringe that applies pressure to the water solution contained in the second syringe to supply the water solution to the soil material; a second measurement unit including a second pressure measurement unit that measures the pressure that the second piston applies to the water flowing through the second piston, and a second control unit that controls the moving speed of the second piston; Equipped with Soil material testing equipment.

2. The first syringe and the second syringe are made of a corrosion-resistant material.

2. The soil material testing device of claim 1.

3. the first control unit includes a first ball screw having a screw shaft connected to the first piston, and a first pulse motor that drives the first ball screw, The second control unit includes a second ball screw having a screw shaft connected to the second piston, and a second pulse motor that drives the second ball screw.

3. The soil material testing device according to claim 1 or 2.

4. a pipe disposed below the first syringe and the second syringe, the pipe having a space communicating with both an internal space of the first syringe and an internal space of the second syringe; a valve disposed in the piping; Equipped with The water solution contained in the second syringe is supplied to the soil material inside the first syringe through the piping.

3. The soil material testing device according to claim 1 or 2.

5. the first piston and the first measuring unit have a space communicating with an internal space of the first syringe, The gas and liquid in the internal space of the first syringe can be discharged to the outside of the soil materials testing apparatus through the space of the first piston and the space of the first measurement unit.

3. The soil material testing device according to claim 1 or 2.

6. the first measuring unit has a first displacement measuring section that measures the displacement of the first piston; 3. The soil material testing device according to claim 1 or 2.

7. A soil material testing method for testing the water absorption and expansion characteristics of a soil material, comprising: placing the soil material into a first syringe; introducing a water solution to be supplied to the soil material into a second syringe; a step of supplying the water solution contained in the second syringe to the soil material by applying pressure to the water solution with a second piston; measuring the pressure that the second piston applies to the water solution; controlling the speed of movement of the second piston; Equipped with Soil material testing methods.

8. The step of placing the soil material into a first syringe comprises: placing a sample of the soil material into the first syringe; a step of pressurizing the sample contained in the first syringe with a first piston to prepare the soil material; Including, The soil material testing method according to claim 7.

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