JP2000081378A - Three-axis cell, three-axis testing device, and three-axis testing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce labor and time required for installing a sample and further miniaturize a three-axis cell itself. SOLUTION: At least either a cap 3 or a pedestal 2 is surrounded for providing an annular member 6 that is mounted to a cylindrical cell 5 so that it can slide in the same direction along with at least one axial move of the cap 3 or the pedestal 2, at least one end of a rubber sleeve 4 is mounted to the annular member 6 and the rubber sleeve 4 is fitted between the pedestal 2 and the cap 3 in the cylindrical cell 5, and the annular member 6 slides along with the expansion/contraction in the axial direction of a sample X, thus displacing the rubber sleeve 4 in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triaxial test cell, a triaxial test apparatus, and a triaxial test method used in ground surveys for designing and constructing structures. More specifically, the present invention uses a triaxial test cell, a triaxial test apparatus, and a triaxial test cell used for measuring deformation characteristics, strength characteristics, and the like of ground materials such as soil and rocks or concrete and bituminous materials. It relates to improvement of the triaxial test method.

[0002]

2. Description of the Related Art A triaxial test is intended to apply a load in a vertical and horizontal triaxial direction to a test object to be tested and to carry out a load test under conditions close to a natural state.
For this reason, as shown in FIG. 6, the triaxial cell 101 is provided with a means for applying a horizontal lateral pressure to the specimen 102 as shown in FIG.
Some have a rubber sleeve 103 covering the side surface of the test piece 102. In this case, by pressing the cell water filled around the rubber sleeve 103, the rubber sleeve 1 is pressed.
A uniform lateral pressure is applied to the test piece 102 via the reference numeral 03.

Here, reference numeral 107 in FIG.
Is a water supply path for introducing cell water into the inside of the device, and reference numeral 106 is an exhaust port for exhausting the water from the device 101 at the same time as the introduction of water. In addition, when the specimen 1 was pressurized in three axial directions,
02 in the axial direction is obtained by detecting the axial displacement measuring detectors 108 and 108 provided on the side of the specimen 102 and the displacement measuring device 1.
09 and 109 are detected.

As described above, in the triaxial test cell 101 in which the lateral pressure is applied to the test piece 102 using the rubber sleeve 103, the upper and lower portions of the rubber sleeve 103 correspond to the test piece 102.
104 and cell bottom plate 105 contacting the upper and lower end surfaces of
(Or the pedestal constituting the bottom plate 105) is generally attached. In this case, since the rubber sleeve 103 covers the entire peripheral surface of the specimen 102 without any gap, the triaxial test can be performed while applying a uniform lateral pressure to the peripheral surface of the specimen 102.

[0005]

However, in the triaxial cell 101 in which the upper and lower portions of the rubber sleeve 103 are mounted on the cap 104 and the cell bottom plate 105 as described above, the rubber sleeve 103 is replaced every time the specimen 102 is replaced.
There is a problem that it takes time and effort because the user has to attach and detach the camera.

As described above, when the axial displacement of the test piece 102 is detected by the axial displacement measuring detectors 108 and 108 and the displacement measuring instruments 109 and 109, each time the rubber sleeve 103 is attached or detached. In addition, since these must also be attached and detached, more work and time are required.

Further, the rubber sleeve 103, the axial displacement measuring detectors 108, 108 and the displacement measuring instruments 109, 109
Is attached to and detached from the triaxial cell 101, this cell 10
A space for storing them or a space for a column is required inside the unit 1. For this reason, there is also a problem that the triaxial cell 101 itself naturally becomes large.

Accordingly, the present invention provides a triaxial cell and a triaxial test apparatus which can reduce the labor and time required for installing a test specimen in a test apparatus, and can reduce the size of the apparatus itself. The purpose of the present invention is to provide a triaxial test method.

[0009]

In order to achieve the above object, an invention according to claim 1 includes a pedestal on which a specimen is placed, a cap for applying an axial load with the pedestal sandwiching the specimen, A rubber sleeve covering the peripheral surface of the specimen, a cylindrical cell surrounding the pedestal, the cap and the rubber sleeve, and holding cell water for applying lateral pressure to the specimen; and a cylindrical cell inside the cylindrical cell. A pressure applying means for applying pressure to the cell water to apply a radial pressure to the specimen through a rubber sleeve, wherein at least one of the cap and the pedestal is axially moved around at least one of the cap and the pedestal. And an annular member attached to the cylindrical cell so as to be slidable in the same direction. The sleeve is attached between the pedestal and the cap in the cylindrical cell, and the annular member slides as the specimen expands and contracts in the axial direction, enabling the rubber sleeve to be displaced in the axial direction. is there.

[0010] In this case, at least one end of the rubber sleeve is an annular member, and the other end is a cap or pedestal (if another annular member is provided, the other annular member).
Are attached to the inside of the cylindrical cell, whereby the inner periphery is a rubber sleeve, the outer periphery is a cylindrical cell, the upper and lower sides are annular members, a cylindrical cell, a donut shape covered with a pedestal. Is formed. The space inside the cylindrical cell is formed in a watertight manner. By supplying water into the cylindrical cell and increasing the pressure, the rubber sleeve is expanded so as to protrude radially inward, and conversely, is lowered to the outer peripheral side. Can be recessed. When the rubber sleeve is dented as in the latter case, there is a space inside the rubber sleeve through which the specimen can pass, so that the specimen can be covered so as to cover the rubber sleeve. Further inflating the rubber sleeve in this state,
A lateral pressure can be applied to the specimen through the rubber sleeve.

Further, once the rubber sleeve is attached to any one of the annular member, the pedestal, and the cap, all that is required is to inflate or depress the rubber sleeve. You don't have to.

According to a second aspect of the present invention, in the three-axis cell according to the first aspect, an axial displacement measuring means for measuring an axial displacement amount of the specimen is provided on a side of the rubber sleeve and the specimen. The measuring means is configured to measure the axial displacement measuring detector provided on the peripheral surface of the rubber sleeve so as to change the position according to the deformation of the specimen in the axial direction, and to measure the displacement of the axial displacement measuring detector. And a displacement measuring device provided inside the cylindrical cell.

Therefore, the axial displacement of the specimen when an axial load or lateral pressure is applied can be measured by using the axial displacement measuring means, and the deformation characteristics and strength characteristics of the specimen can be obtained. Also, since the rubber sleeve is provided so that it does not have to be attached and detached each time the specimen is installed,
The shaft displacement measuring detection body and the displacement measuring device according to the present invention can be used continuously as they are once installed.

According to a third aspect of the present invention, there is provided the first or second aspect.
A triaxial test apparatus is provided with the triaxial cell described above. In this case, the triaxial test apparatus includes the above-described triaxial cell in addition to the loading frame and the back pressure tank required for the triaxial test, so that the rubber sleeve and the axial displacement measuring means can be provided without attachment / detachment. Specimens can be installed.

According to a third aspect of the present invention, there is provided a method for performing a triaxial test using the triaxial cell according to the first or second aspect. The triaxial cell makes it possible to perform a triaxial test by installing a test specimen without removing the rubber sleeve once attached.According to this method, the rubber sleeve and the shaft displacement measuring means must be used for each test. Does not require time and effort to attach and detach.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIGS. 1 and 2 show one embodiment of a triaxial cell of the present invention and a triaxial test method performed using the triaxial cell. The triaxial cell 1 is a part of an apparatus for performing a compression test of a specimen X cut out of the ground at the original position, and detects various properties such as mechanical properties of the ground from the test result of the specimen X. It is. The triaxial cell 1 of the present embodiment includes a pedestal 2, a cap 3, a rubber sleeve 4, a cylindrical tubular cell (hereinafter referred to as a "cylindrical cell") 5, a pressure applying means 10, a cylindrical cell An internal space (hereinafter, referred to as a “cylindrical cell internal space”) 28 is provided, and is formed so that the specimen X can be compressed in three axial directions. Note that, as the specimen X to be tested in the present embodiment, a specimen cut into a column shape from the ground to be investigated is used.

The pedestal 2 and the cap 3 are loaded with an axial load W sandwiching the specimen X from above and below, and the specimen X
Is to change the distance between both end faces. For this reason, the pedestal 2 and the cap 3 are provided so that their relative distances can be changed, but there is no particular limitation on which one is fixed or both are movable. In addition, the movement of the pedestal 2 and the cap 3 differs depending on, for example, whether the jack is installed above or below the loading frame. That is, when the jack is on the top, the pedestal 2 does not move and the cap 3 moves,
Conversely, when the jack is below, the pedestal 2 is movable and the cap 3 is immobile. Although not particularly shown, the loading frame and the jack constitute a triaxial testing apparatus together with the triaxial cell 1 of the present embodiment. In this case, a reaction force of the axial load W is received by the external loading frame or the like.

Here, the pedestal 2 serves as a table on which the specimen X is mounted, and is formed in the same cylindrical shape as the specimen X in the present embodiment. A flange 11 forming a cell bottom plate is integrally formed on the bottom peripheral surface of the pedestal 2. The pedestal 2 and the cylindrical cell 5 are removably assembled by fitting a flange 11 to an end of the cylindrical cell 5. In order to prevent the pedestal 2 and the cylindrical cell 5 from separating from each other when the internal space 28 of the cylindrical cell is set to a high pressure in order to apply a side pressure, separation of a key or the like penetrating through the cylindrical cell 5 and protruding toward the flange 11 is prevented. It is fixed by the member 12. Therefore, the floating of the cylindrical cell 5 can be prevented against the lift due to the lateral pressure. Note that an O-ring 13 is provided between the pedestal 2 and the flange 11 of the cylindrical cell 5 so as to be sealed.

The pedestal 2 has a perforated plate 1 inside.
4 and a water supply / drainage path 15. The perforated plate 14 is provided on the upper surface side of the pedestal 2 in contact with the specimen X so as to supply and drain water through a water supply and drain passage 15, and uses the pressure water to correspond to the pore water pressure of the specimen X. Pressure is being applied. The water supply / drain passage 15 is provided with a valve 16, a back pressure tank (not shown), and the like.

The pedestal 2 further includes a load cell 18 capable of measuring a load when an axial load W is loaded on the specimen X.
Built-in. Therefore, the stress applied to the specimen X can be measured using the axial load W measured by the load cell 18. The load cell 18 is built in the cap 3 instead of the pedestal 2, and the load cell 18
Of course, it is also possible to measure the axial load W.

The cap 3 is set above the specimen X so as to load an axial load W across the specimen X together with the pedestal 2, and is formed in a cylindrical shape like the pedestal 2. . The cap 3 having the peripheral surface on which the flange 19 is formed is fastened by a fastening member 20 such as a bolt.
It is fastened to an annular member 6 provided between the cap 3 and the cylindrical cell 5.

A pedestal 2 is provided inside the cap 3.
Similarly to the above, a perforated plate 21 and a water supply / drainage path 22 are provided. Further, the water supply / drainage path 22 is provided with a valve 23, a burette (not shown), and the like.

An annular member 6 provided between the cap 3 and the cylindrical cell 5 surrounds at least one of the cap 3 and the pedestal 2 and moves as the one of the cap 3 and the pedestal 2 moves in the axial direction. It is attached to the cylindrical cell 5 so as to slide in the direction. The annular member 6 in the present embodiment is formed in a cylindrical shape as shown in FIG. The annular member 6 includes an upper edge 25 and an edge 2.
5 is integrally fastened to the cap 3 via a fastening member 20 provided on the cap 5, and a gap between the cap 3 and the cap 3 is O
It is kept watertight by a ring 26. In the present embodiment, the cap 3 is movable in the axial direction. At this time, the annular member 6 moves up and down integrally with the cap 3. The O-ring 27 on the outer peripheral surface of the annular member 6 includes the annular member 6 moving up and down and the cylindrical cell 5.
Is provided so as to maintain the contact between them in a watertight manner. In addition, the outer peripheral surface of the upper edge portion 25 of the annular member 6 can be removed by sliding the cylindrical cell 5 upward.
The cap 3 is formed so as to be flush with the outer peripheral surface of the flange 19 without any step. Therefore, for example, when the rubber sleeve 4 is damaged, the cylindrical cell 5 can be detached from the triaxial cell 1 to facilitate the replacement operation of the rubber sleeve 4.

The cylindrical cell 5 is provided so as to form the outer wall of the triaxial cell 1. The cylindrical cell 5 comes into contact with the annular member 6 at the upper part of the triaxial cell 1 and the pedestal 2 at the lower part thereof in a watertight manner. Pressurization in the axial cell 1 is enabled. As a space that can be pressurized in this way, a cylindrical cell internal space 28 is formed inside the triaxial cell 1 of the present embodiment and is separated from the external space by the cylindrical cell 5, the cap 3, and the like.

A water supply / drain port 29 for supplying / draining cell water (a liquid for applying a lateral pressure to the specimen X from the cylindrical cell internal space 28) to the cylindrical cell internal space 28 from the outside is provided below the cylindrical cell 5. A water supply / drain passage 30 for introducing cell water to the water supply / drain opening 29 is provided. A valve 31 is provided in the middle of the water supply / drain passage 30, and a water tank (not shown) for storing and supplying the cell water is provided at the end of the valve 31. On the other hand, the space 28 inside the cylindrical cell
An exhaust port 33 and an exhaust path 34 for exhausting air from are provided, and a valve 35 is provided in the middle of the exhaust path 34. Thus, the water supply / drainage means for supplying / draining the cell water and the exhaust means for exhausting the cylindrical cell internal space 28 form the pressure applying means 10 for applying the pressure to the specimen X inward in the radial direction via the rubber sleeve 4. ing.

A rubber sleeve 4 having appropriate elasticity and thickness is provided in the cylindrical cell space 28 so as to cover the peripheral surface of the test sample X. Since the upper and lower portions of the rubber sleeve 4 are fastened to the annular member 6 and the pedestal 2, respectively, the rubber sleeve 4 is mounted so as to divide the cylindrical cell inner space 28 into an inner side and an outer side. In the present embodiment, the fastening bands 37 and 38 as shown are used as fastening means for fastening the rubber sleeve 4. However, if the fastening bands are closely adhered to maintain water tightness, the fastening means is particularly like this fastening band. It is not limited to the thing.

The rubber sleeve 4 is called a rubber sleeve for convenience because a synthetic rubber material is used, but it is not particularly limited as long as it has pressure resistance and elasticity. Absent. In addition to synthetic rubber, an elastomer material called a high elastic polymer material such as vinyl resin or polyethylene can be used, or silicone resin or silicone rubber can also be used.

In the triaxial cell 1 of this embodiment, the rubber sleeve 4 is covered with the cylindrical cell 5 so as to cover the specimen X in this manner.
Because it is provided inside, it is possible to apply a uniform lateral pressure to the placed specimen X from the outside via the rubber sleeve 4. That is, since the pressure outside the rubber sleeve 4 can be adjusted independently from the inside of the rubber sleeve 4, if the pressure outside the rubber sleeve 4 (that is, the space 28 in the cylindrical cell) is higher than the inside, the pressure difference causes The generated lateral pressure (effective restraint pressure) is applied to the side surface of the specimen X. On the other hand, if the pressure outside the rubber sleeve 4 is equal to or lower than the atmospheric pressure, on the other hand, the rubber sleeve 4 does not apply any lateral pressure to the specimen X.

As described above, the lower portion of the rubber sleeve 4 is fastened to the fixed pedestal 2 while the upper portion is fastened to the annular member 6 slidable in the axial direction. Even if it moves in the axial direction, it is provided so that the specimen X can always be covered by following this movement.

Between the rubber sleeve 4 and the cylindrical cell 5 (to the side of the specimen X), the axial displacement measuring detectors 8 and 8 are used to measure the displacement of the specimen X in the axial direction. Vessel 9,
9 is provided. The axial displacement measuring detectors 8, 8 are fixedly provided on the outer peripheral surface of the rubber sleeve 4, and move as the rubber sleeve 4 is displaced in the axial direction.
On the other hand, the displacement measuring devices 9 and 9
8 is provided so as to read the displacement, and at a position (for example, a rod 17 fixed to the bottom plate) inside the cylindrical cell 5 and corresponding to the axial displacement measuring detectors 8, 8.
It is installed without changing the relative position with the bottom. The two axial displacement measuring detectors 8 and 8 and the displacement measuring devices 9 and 9 are provided as shown in the figure, and the specimen X is measured by using the difference in displacement when the rubber sleeve 4 expands and contracts in the axial direction. Calculate the average axial strain.

The outline of performing a triaxial test using the triaxial cell 1 configured as described above will be described below.

When the test specimen X is installed in the apparatus 1, with the cap 3 removed as shown in FIG.
The specimen X is suctioned from above and suspended from the upper surface, and lowered to the pedestal 2. At this time, the rubber sleeve 4 is widened by setting the cylindrical cell space 28 to a negative pressure. That is,
When the specimen X is installed in this manner, a negative pressure is applied to the cylindrical cell space 28 using the pressure applying means 10 in order to make the inner diameter of the rubber sleeve 4 larger than the diameter of the specimen X. When a negative pressure is applied, the inside of the rubber sleeve 4 communicates with the outside and has a normal pressure, so that the rubber sleeve 4 is sucked and swells radially outward so that the specimen X can pass through. It will expand to an extent. Further, in this embodiment, even if the inside of the cylindrical cell space 28 is made equal to the atmospheric pressure, a space enough to allow the specimen X to pass can be secured as shown in FIG.

It is a preferable embodiment to put the specimen X in a net such as a stocking and raise and lower it on the pedestal 2 because the specimen X can be easily taken in and out.

As described above, since the rubber sleeve 4 of the present invention is always fastened to both the pedestal 2 and the annular member 6 in a water-tight manner, the rubber sleeve 4 can be used only by changing the pressure in the cylindrical cell space 28. The test piece X can be brought into close contact with or separated from the test piece X, so that it is not necessary to attach and detach the rubber sleeve 4 every time the test piece X is installed.

After placing the specimen X on the pedestal 2,
The cap 3 is placed on the upper surface of the specimen X as shown in FIG. In this case, the cap 3 is inserted from above so as to pass through the annular member 6, and is integrated with the annular member 6 by the fastening member 20 as shown in FIG. You. As a result, the specimen X is air-tightly (water-tightly) covered with the cap 3 and the pedestal 2 on the upper and lower sides and the rubber sleeve 4 on the periphery.

When the installation is completed up to this point, a triaxial compression test similar to the usual is performed. That is, as shown in FIG. 1, an axial load W is applied while applying a lateral pressure to the specimen X,
The magnitude of the load and the amount of displacement in the axial direction are measured to determine these relationships. During the test, the lateral pressure
The cell water supplied to 8 is pressed on the peripheral surface of the specimen X via the rubber sleeve 4 by pressurizing. Note that the cell water in the present embodiment is not always filled in the cylindrical cell space 28 from the beginning, and is supplied while the gas is exhausted from the exhaust port 33 after the specimen X is installed. .

Further, the magnitude of the axial load W loaded on the specimen X can be measured by the load cell 18. At this time, the length of expansion and contraction of the specimen X in the axial direction is determined by the positions of the two axial displacement measuring detectors 8 and 8 which are fixed to different heights of the rubber sleeve 4 in advance within the height range of the specimen X. Is determined by detecting

As described above, according to the triaxial test method of the present invention in which the test is performed using the triaxial cell 1, the system for measuring the axial displacement, that is, the rubber sleeve 4 and the detector 8 for measuring the axial displacement are used for each test. The labor and time required for installation and the like are greatly reduced because labor for mounting is omitted. According to the present invention, the integrated cylindrical cell 5 incorporating the displacement measuring means 7 is also provided.
Compact three-axis cell 1
Can be formed, and further, this triaxial cell 1 is adopted,
Accurate measurement that does not include a bedding error on the end face of the specimen X is possible.

Next, another embodiment of the present invention will be described with reference to FIGS.
This will be described based on an example shown in FIG. In the above-described embodiment, the lower portion of the rubber sleeve 4 is fastened to the pedestal 2, whereas in the triaxial cell 1 of the present embodiment, the pedestal 2
Is surrounded by a fixed annular portion integrally formed with the cylindrical cell 5, and a rubber sleeve 4 is fastened to the annular portion.

The cylindrical cell 5 of the present embodiment has a
It is formed with a bottom plate 5a so as to form a lower annular portion of the cylindrical cell space 28. In the center of the bottom plate 5a, a hole 5 into which the pedestal 2 is fitted with a gap.
d is provided. Further, a groove 5 is formed on the inner peripheral surface of the hole 5d.
The groove 5b is provided with an O-ring 13 which contacts the pedestal 2 and the cylindrical cell 5 and seals it without leakage. As described above, since the cell bottom is formed by a part of the cylindrical cell 5, the water supply / drain port 29 to the cylindrical cell space 28 is connected to the bottom 5a as shown in the figure.
And the water supply / drainage passage 30 is
a.

Further, the cylindrical cell 5 is formed with an annular boss 5c projecting upward along the outer peripheral surface of the pedestal 2. In the present embodiment, the lower portion of the rubber sleeve 4 is placed around the boss 5c, and the rubber band 4 is fastened by a fastening band 38 from above. Therefore, the cylindrical cell space 28 is formed watertight by the cylindrical cell 5, the annular member 6 and the rubber sleeve 4.

On the other hand, a slightly smaller flange 11 is formed on the peripheral surface of the pedestal 2. This flange 11
Abuts against the back side surface of the bottom plate 5a to relatively position the pedestal 2 and the cylindrical cell 5. The pedestal 2 and the cylindrical cell 5 are fastened and fixed in a fixed state by a fastening member 39 such as a bolt, for example.

Although not shown, the cylindrical cell 5 of the present embodiment is formed so as to be appropriately divided in the circumferential direction so that the cylindrical cell 5 can be removed without removing other members. is there. For example, although the structure for division is not particularly shown, the cylindrical cell 5 can be vertically divided at the dashed line shown in FIG. 3, and the divided upper part is vertically divided into three equal parts, for example. To be removable.
By doing so, since only the cylindrical cell 5 can be separated from the triaxial cell 1, even if the rubber sleeve 4 is damaged, the operation of replacing the rubber sleeve 4 can be performed.

Further, in the triaxial cell 1, the bottom plate 5a is formed as a part of the cylindrical cell 5, and the cylindrical cell 5 and the bottom plate 5a are integrated and their relative positions change even during the triaxial test. There is no. Therefore, the displacement measuring devices 9 in this embodiment are directly attached to the inner peripheral surface of the cylindrical cell 5. In this case, the displacement measuring devices 9 and 9 can accurately measure the positions of the axial displacement measuring detectors 8 and 8 based on the bottom 5a without using a rod or the like.

In this triaxial cell 1, the rubber sleeve 4 is fastened not to the pedestal 2 but to the cylindrical cell 5, so that only the pedestal 2 can be removed downward without removing the rubber sleeve 4. Is possible. Therefore, in this embodiment, the specimen X can be taken in and out from the upper part in the same manner as in the above-described embodiment, and the pedestal 2 is taken out downward (or with respect to the fixed pedestal 2 as shown in FIG. 4). The specimen X can be taken in and out by moving the part other than 2 relatively upward).

As described above, in the present embodiment, the rubber sleeve 4 is always fastened to both the cylindrical cell 5 and the annular member 6 in a water-tight manner. The test piece X can be closely attached to the test piece X or separated from the test piece X, so that it is not necessary to attach and detach the rubber sleeve 4 every time the test piece X is installed.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in each of the above-described embodiments, the triaxial cell 1 in which the annular member 6 is provided around the cap 3 (the case of the first embodiment is schematically shown in FIG. 5A again) has been described. The annular member 6 is not particularly limited to
Alternatively, both the cap 3 and the pedestal 2 may be provided.
When both the cap 3 and the pedestal 2 are movable, they may be movably attached to the cylindrical cell 5. As shown in FIG. 5B, an annular member 6 may be provided around the slidable pedestal 2, and a rubber sleeve 4 may be mounted between the annular member 6 and the fixed cap 3. . In this case, the annular member 6
Is mounted slidably in the axial direction, and the lower side of the rubber sleeve 4 is fastened to the annular member 6. For this reason,
As in the previous embodiments, the rubber sleeve 4 can follow the expansion and contraction of the specimen X, and the specimen X can be taken in and out of the triaxial cell 1 without removing the rubber sleeve 4 (in this case, The specimen X can be taken in and out from the lower side of the triaxial cell 1).

The annular member 6 provided on the triaxial cell 1
Is not limited to one as in these embodiments.
That is, as shown in FIG. 5C, the annular members 6 and 6 can be provided on the upper and lower portions of the triaxial cell 1 respectively. In such a triaxial cell 1, for example, even if the axial displacement measuring detectors 8, 8 are deviated from their original positions, the adjustment becomes easier by moving the upper and lower annular members 6, 6 in the axial direction, respectively. . When one of the annular members 6 can be fixed to the cylindrical cell 5, if the lower annular member 6 is fixed as shown in FIG. 5D, the triaxial shaft shown in FIG. The structure is the same as that of the cell 1, and conversely, if the upper side is fixed as shown in FIG. 5 (E), the structure becomes the same as that shown in FIG. 5 (B).

In the above embodiment, the cylindrical cell space 28 is filled with the cell water. However, as the cell water, not only normal water but also a viscous fluid or the like can be used. Alternatively, it is also possible to use gas instead of liquid.

Further, in the embodiments described so far, the structure of the triaxial cell 1 has been described, and the outline of the triaxial test method using the triaxial cell 1 has been described. In addition to the triaxial cell 1, a loading frame, a back pressure tank, and the like are generally required, and these may constitute a triaxial test apparatus. Triaxial cell 1 of the present invention
It is needless to say that the same effect as described so far can be achieved even when incorporated as a component of such a three-axis test apparatus.

[0052]

As is apparent from the above description, according to the triaxial cell of the first aspect of the present invention, the rubber sleeve is projected radially inward by adjusting the pressure of the cell water in the cylindrical cell. In addition, since it is possible to make the outer peripheral side concave, it is possible to reduce the labor and time for attaching and detaching the rubber sleeve every time the specimen is installed.

In addition, in the triaxial test, a lateral pressure can be applied to the specimen through the rubber sleeve.
The conventional accurate measurement that does not include the bedding error on the end face of the specimen can be performed in a short time. In addition, it is possible to design an integrated cylindrical cell incorporating the displacement measuring means, so that the size of the triaxial cell can be reduced.

According to the second aspect of the present invention, the axial displacement of the specimen when an axial load is applied is measured by the axial displacement measuring means, and the deformation characteristics and strength characteristics of the specimen are measured. Can be requested. Moreover, this shaft displacement measuring means
Since it is configured with the axial displacement measuring detector and the displacement measuring device so that once it is installed, it is not necessary to attach / detach each time of the test, the labor and time required for the triaxial test can be reduced.

Further, according to the three-axis test apparatus of the third aspect of the present invention, since the three-axis cell is provided with the above-described three-axis cell, the test piece can be installed without attaching or detaching the rubber sleeve or the axial displacement measuring means. And accurate measurement can be performed in a short time.

According to the three-axis test method of the present invention, the three-axis test can be performed without removing the rubber sleeve and the shaft displacement measuring means once mounted. The installation time and labor can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a triaxial cell of the present invention.

FIG. 2 is a schematic view showing a state in which a specimen is placed in a triaxial cell and a cap is placed thereon.

FIG. 3 is a longitudinal sectional view showing another embodiment of a triaxial cell.

FIG. 4 is a schematic view showing an example of a state in which a specimen is installed in a triaxial cell in another embodiment shown in FIG.

FIG. 5 is a schematic diagram showing a configuration of a triaxial cell of the present invention;
(A) and (B) have one annular member, and (C) to (E) have two
It is provided one by one.

FIG. 6 is a longitudinal sectional view simply showing the configuration of a conventional triaxial cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Triaxial cell 2 Pedestal 3 Cap 4 Rubber sleeve 5 Cylindrical cell (cylindrical cell) 6 Annular member 7 Displacement measuring means 8 Detector for measuring axial displacement 9 Displacement measuring instrument 10 Pressure applying means W Axial load X Specimen

Claims (4)

[Claims] 1. A pedestal on which a specimen is placed, a cap for applying an axial load across the specimen together with the pedestal, a rubber sleeve covering the peripheral surface of the specimen, and the pedestal. A cylindrical cell surrounding the cap and the rubber sleeve and holding cell water for applying lateral pressure to the specimen; and applying pressure to the cell water in the cylindrical cell through the rubber sleeve. A pressure applying means for applying a radial pressure to the specimen, wherein the cylinder surrounds at least one of the cap and the pedestal and is slidable in the same direction along with the axial movement of at least one of the cap and the pedestal. An annular member attached to the annular cell, wherein at least one end of the rubber sleeve is attached to the annular member and the rubber sleeve is Mounted between the pedestal and the cap in a cell, allowing the annular member to slide and displace the rubber sleeve in the axial direction as the specimen expands and contracts in the axial direction. A triaxial cell characterized by the following. 2. An axial displacement measuring means for measuring an axial displacement amount of the test piece is provided on a side of the rubber sleeve and the test piece, and the axial displacement measuring means is provided in an axial direction of the test piece. An axial displacement measuring detector provided on the peripheral surface of the rubber sleeve so as to change its position with deformation, and a displacement provided inside the cylindrical cell so as to measure the displacement of the axial displacement measuring detector. 3. The triaxial cell according to claim 1, comprising a measuring instrument. 3. A triaxial test apparatus comprising the triaxial cell according to claim 1 or 2. 4. A triaxial test method comprising performing a triaxial test using the triaxial cell according to claim 1.