Auxiliary device for measuring Poisson's ratio of stone sample

Abstract

The utility model belongs to the technical field of stone sample Poisson's ratio measurement, and discloses an auxiliary device for measuring the Poisson's ratio of a stone sample, so as to solve the problems that the measurement precision is influenced and the number of measurement points is small in the prior art, the device comprises an installation ring, six installation plates are uniformly distributed on the installation ring along the circumferential direction, the six installation plates are divided into three groups, each group of mounting plates are arranged oppositely, sliding sleeve frames with adjustable height positions are arranged on the mounting plates, dial gauge mounting ports are formed in the upper ends of the sliding sleeve frames, and limiting clamping caps for fixing dial gauges are movably arranged at the tops of the sliding sleeve frames. According to the rock Poisson's ratio measuring device, the multi-point precision measurement can be realized, a plurality of groups of dial indicators are arranged, a plurality of test point positions are formed by contact points of the dial indicators and a rock sample, and stress-deformation data of a plurality of different positions can be recorded and analyzed before the rock is damaged, so that the measurement precision of the rock Poisson's ratio is improved. And errors caused by measurement by using a magnetic gauge stand are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of stone sample Poisson's ratio measurement, in particular to an auxiliary device for measuring the Poisson's ratio of a stone sample. Background Art

[0002] Current standards for determining the Poisson's ratio of rock use either the resistance strain gauge method or the micrometer method. The resistance strain gauge method requires test materials such as a static resistance strain gauge, a bridge, a megohmmeter, and a resistance strain gauge, placing high demands on test conditions.

[0003] The micrometer method requires a micrometer (percentage) indicator, a magnetic stand, and lower requirements for test materials than the micrometer. However, since the indicator head is symmetrically placed in the middle of the specimen when measuring radial displacement using a magnetic stand, inaccurate placement will lead to errors. In addition, when the specimen is axially compressed, the deformation of the middle part of the specimen will be slightly greater than that of the upper and lower parts, affecting the measurement accuracy.

[0004] In addition, the traditional measurement method of the dial indicator method has a small number of measurement points, which also leads to insufficient measurement accuracy. For example, CN202321796144.3 discloses a test device for measuring the Poisson's ratio of concrete using the dial indicator method.

[0005] Therefore, it is necessary to design an auxiliary device for measuring the Poisson's ratio of stone samples to solve the above problems. Utility Model Content

[0006] The purpose of the utility model is to solve the problems of affecting measurement accuracy and insufficient measurement points in the prior art, and proposes an auxiliary device for measuring the Poisson's ratio of a stone sample.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] An auxiliary device for measuring the Poisson's ratio of a stone sample comprises a mounting ring, on which six mounting plates are evenly distributed along the circumferential direction. The six mounting plates are divided into three groups, and each group of mounting plates is arranged opposite each other. A sliding sleeve frame with adjustable height is mounted on the mounting plate, and a micrometer mounting port is provided at the upper end of the sliding sleeve frame. A limit cap for fixing the micrometer is also movably mounted on the top of the sliding sleeve frame.

[0009] Furthermore, each mounting plate is provided with a card slot, and the sliding sleeve frame is provided with an open slot corresponding to the card slot. Card blocks are installed in the card slot and the open slot, and the card blocks can be pressed and retracted into the card slot.

[0010] Furthermore, each mounting plate is provided with a mounting cavity, the card slots are arranged on both sides of the mounting cavity, a spring is installed in the mounting cavity, both ends of the spring are provided with pressure plates, a slide rod is fixed on the pressure plate, and the slide rod is fixed to the card block.

[0011] Furthermore, three open slots are evenly spaced and spaced apart on the sliding sleeve frame.

[0012] Furthermore, a marking line is provided on the lower portion of the mounting plate.

[0013] Furthermore, the limiting cap is a rubber limiting cap.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] This new device can achieve multi-point measurement accuracy: by installing multiple micrometers, the device forms multiple test points at the contact points with the rock sample. This design can record and analyze stress-deformation data at multiple different locations before rock failure, thereby improving the measurement accuracy of the rock's Poisson's ratio and avoiding the errors caused by the use of magnetic stand.

[0016] The utility model has an adjustable test position, and the height between each mounting plate and the corresponding sliding sleeve frame is adjustable, allowing staff to flexibly adjust the test position of the micrometer according to rock samples of different sizes. This flexibility ensures the applicability and accuracy of the device under different experimental conditions.

[0017] The utility model can fix the position of the micrometer firmly by clamping the rubber limiting clamping cap on the top of the sliding sleeve frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the present utility model.

[0019] Figure 2 It is a structural diagram of the limit clamp cap of the utility model.

[0020] Figure 3 This is a cross-sectional connection diagram of the mounting plate and the sliding sleeve frame of the utility model.

[0021] Figure 4 For this utility model Figure 3 A partial enlarged schematic diagram.

[0022] The meanings of the accompanying figures are as follows: 1. Mounting ring; 2. Mounting plate; 3. Slide frame; 4. Slot; 5. Opening slot; 6. Block; 7. Spring; 8. Mounting cavity; 9. Slide rod; 10. Limiting cap; 11. Pressure plate; 12. Marking line; 13. Micrometer mounting port. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1-4As shown, an auxiliary device for measuring the Poisson's ratio of a stone sample comprises a mounting ring 1, to which six mounting plates 2 are evenly distributed along the circumference. Marking lines 12 are provided on the lower portions of the mounting plates 2. The six mounting plates 2 are arranged in three groups, with each group of mounting plates 2 arranged opposite each other. A sliding sleeve 3 with adjustable height is mounted on the mounting plates 2. A micrometer mounting opening 13 is provided at the upper end of the sliding sleeve 3. A rubber limit cap 10 for securing the micrometer is also movably mounted on the top of the sliding sleeve 3.

[0025] Each mounting plate 2 is provided with a card slot 4, and each mounting plate 2 is provided with a mounting cavity 8. The card slots 4 are arranged on both sides of the mounting cavity 8. The sliding sleeve frame 3 is provided with an open slot 5 corresponding to the card slot 4. There are three open slots 5 evenly spaced and arranged on the sliding sleeve frame 3. Card blocks 6 are installed in the card slots 4 and the open slots 5. A spring 7 is installed in the mounting cavity 8. Pressure plates 11 are fixed at both ends of the spring 7. A slide rod 9 is fixed on the pressure plate 11. The slide rod 9 is fixed to the card block 6. The card block 6 can be pressed and retracted into the card slot 4.

[0026] In this embodiment, the inner diameter of the mounting ring 1 is 100 mm, which is determined according to the rock sample size and standard micrometer size specified in GB / T50266-2013, and is suitable for rock samples with a diameter of 48-54 mm.

[0027] The sliding sleeve frame 3 can be adjusted to a height of 25, 50, or 75 mm.

[0028] When adjusting the height of the sliding frame 3, the block 6 is pressed and retracted into the slot 4. Then, the sliding frame 3 is moved to the required height in conjunction with the marking line 12. Under the spring force of the spring 7, the block 6 is pushed out of the open slot 5 by the slide rod 9, and the position of the sliding frame 3 is limited.

[0029] The specific operations are as follows:

[0030] 1. Process rock samples. According to GB / T50266-2013 Engineering Rock Test Methods, test specimens can be prepared from drilled cores or rock blocks. Their dimensions should meet the following conditions:

[0031] 1.1. The diameter of the cylindrical specimen should be 48mm-54mm.

[0032] 1.2. The diameter of the specimen should be 10 times greater than the diameter of the largest particle in the rock.

[0033] 1.3. The ratio of specimen height to diameter is 2.0-2.5.

[0034] 2. After assembling the device, adjust the height of each set of sliding sleeve frames 3 according to actual requirements. Then, place the assembled device on the loading platform of the microcomputer servo universal testing machine, and then install the dial indicator in the dial indicator installation port 13 respectively, and use the limit cap 10 to lock it in place.

[0035] 3. Then place the rock sample in the center of the mounting ring 1 so that it contacts the dial indicator head. Use a continuous loading method at a speed of 0.5-1.0 MPa per second. Load step by step and record the readings of each group of dial indicators. Save the pressure-displacement curve on the testing machine until the rock sample is destroyed.

[0036] 4. Data processing:

[0037] The axial strain value of each stress level and The radial strain values of the same stress should be calculated according to the following formulas:

[0038]

[0039] Where: —Axial strain values at each level of stress;

[0040] -and The radial strain value at the same stress;

[0041] △L—Average axial deformation under various load levels (mm);

[0042] △D—mean radial deformation under the same load as △L (mm; obtained by the average value of the three corresponding micrometer readings)

[0043] L——Axial measurement gauge length or specimen height (mm)

[0044] D——test piece diameter (mm)

[0045] After obtaining each set of axial and radial strains, the axial and radial strain relationship curves are drawn.

[0046] The average Poisson's ratio of rock is calculated according to the following formula:

[0047]

[0048] Where: —Average Poisson's ratio of rock;

[0049] —Radial strain value at nth level loading;

[0050] —Radial strain value at the (n-1)th level of loading;

[0051] —Axial strain value at nth level loading;

[0052] —Axial strain value at the (n-1)th level of loading;

[0053] The Poisson's ratio of rock is calculated according to the following formula:

[0054]

[0055] Where: —Poisson's ratio of rock;

[0056] —Radial strain value of 1 / 2 total loading level;

[0057] —Axial strain value of 1 / 2 total loading level.

Claims

1. An auxiliary device for measuring the Poisson's ratio of a stone sample, comprising a mounting ring (1), characterized in that: Six mounting plates (2) are evenly distributed along the circumferential direction on the mounting ring (1). The six mounting plates (2) are divided into three groups. The mounting plates (2) of each group are arranged opposite each other. A sliding sleeve frame (3) with adjustable height is installed on the mounting plates (2). The upper end of the sliding sleeve frame (3) is provided with a micrometer mounting port (13).

2. The auxiliary device for measuring the Poisson's ratio of a stone sample according to claim 1 is characterized in that: The mounting plates (2) are each provided with a card slot (4), the sliding sleeve frame (3) is provided with an open slot (5) corresponding to the card slot (4), and a card block (6) is installed in the card slot (4) and the open slot (5), and the card block (6) can be pressed and retracted into the card slot (4).

3. The auxiliary device for measuring the Poisson's ratio of a stone sample according to claim 2 is characterized in that: The mounting plate (2) is provided with a mounting cavity (8), the card slot (4) is arranged on both sides of the mounting cavity (8), a spring (7) is installed in the mounting cavity (8), both ends of the spring (7) are provided with a pressure plate (11), a slide bar (9) is fixed on the pressure plate (11), and the slide bar (9) is fixed to the card block (6).

4. The auxiliary device for measuring the Poisson's ratio of a stone sample according to claim 3, characterized in that: The top of the sliding sleeve frame (3) is also movably provided with a limit cap (10) for fixing the micrometer.

5. The auxiliary device for measuring the Poisson's ratio of a stone sample according to claim 4, characterized in that: Three open slots (5) are evenly spaced and spaced apart on the sliding sleeve frame (3).

6. The auxiliary device for measuring the Poisson's ratio of a stone sample according to claim 5, characterized in that: A marking line (12) is provided on the lower portion of the mounting plate (2).

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