Test method and device for measuring rock density

Abstract

The invention relates to a test method and device for measuring rock density, and belongs to the field of rock density measurement, and the test method comprises the following steps: step 1, step 2, step 3, step 4 and step 5. Wherein in the third step, an opening container capable of containing water is filled with a proper amount of water, after water on the outer surface of the opening container is wiped, the opening container is placed on a common balance to weigh mass, and then peeling is conducted; and 4, slowly placing the wax-sealed test piece in the open container, fixing the fine line on the test piece on the cross bar of the device so that the test piece is suspended in water without touching the inner wall of the container and the water in the container does not overflow, and reading stable readings displayed on the common balance to obtain the mass of the same volume of water of the wax-sealed test piece. Compared with the existing standard, the method has the advantages that the detection result is accurate, and the calculated value of the rock mass density is consistent with the value calculated by a test method specified in the Standard for Test Method of Engineering Rock Mass (GB / T 50266-2013); equipment is simple, and economic cost is saved; and detection and calculation methods are relatively simple and convenient.

Description

Technical Field

[0001] This invention relates to the field of rock density determination, and more specifically, to a test method and apparatus for determining rock density. Background Technology

[0002] The testing and inspection unit shall test the density of the rock blocks provided by the client in accordance with relevant standards and methods and issue a data report. The "Standard for Test Methods of Engineering Rock Mass" (GB / T50266-2013) stipulates that the density test of rock blocks may employ the volumetric method, the underwater weighing method, or the wax-sealing method, and shall meet the following requirements: 1. For all types of rocks that can be prepared into regular specimens, the volumetric method is preferred; 2. Except for rocks that disintegrate, dissolve, or shrink and swell when exposed to water, the underwater weighing method can be used; 3. For rocks that cannot be measured using the volumetric method or the underwater weighing method, the wax-sealing method is preferred.

[0003] According to the standard (GB / T 50266-2013), the test procedure for the wax sealing method is as follows: 1. Prepare a sample from a representative rock and weigh it. If measuring dry density, first bake the sample at 105℃~110℃ for 24 hours, then remove it and place it in a desiccator to cool to room temperature before weighing it. 2. Tie a thin thread to the sample and place it in molten wax at about 60℃ for about 1 to 2 seconds to evenly coat the surface of the sample with a layer of wax. After cooling, weigh the wax-sealed sample. 3. Weigh the wax-sealed sample in water.

[0004] However, in the above test steps, the weighing of the wax-sealed specimen in water requires the use of an underwater weighing device. Common devices for underwater weighing include hydrostatic balances, which are more expensive than ordinary balances, increasing the cost of the testing equipment. Furthermore, hydrostatic balances must be used with compatible accessories during underwater weighing, and these accessories are difficult to repair or reuse if damaged or lost. In addition, the testing and calculation methods according to existing standard test methods are quite cumbersome. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and to propose a test method and apparatus for determining the density of rock blocks.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A test method for determining the density of a rock block includes the following steps:

[0008] Step 1: Take representative rocks and prepare them into test specimens. The test specimens should be rounded rock blocks with a side length of 40mm to 60mm. Weigh them. If measuring dry density, first bake the test specimens at 105℃ to 110℃ for 24 hours, then take them out and place them in a desiccator to cool to room temperature, and then weigh them.

[0009] Step 2: Tie a thin thread to the specimen and place it in molten wax at a temperature of about 60℃ for about 1 to 2 seconds to make the surface of the specimen evenly coated with a layer of wax film with a thickness of about 1 mm. If there are air bubbles in the wax film, puncture them with a hot needle and smooth them with wax. After cooling, weigh the wax-sealed specimen.

[0010] Step 3: Fill an open container with an appropriate amount of water, wipe the surface of the container dry, weigh it on a regular balance, and then tare it.

[0011] Step 4: Slowly place the wax-sealed specimen into the open container, fix the thin thread on the specimen to the horizontal bar of the device so that the specimen is suspended in the water without touching the inner wall of the container and the water in the container does not overflow. Read the stable reading displayed on the ordinary balance to obtain the mass of the same volume of water as the wax-sealed specimen.

[0012] Step 5: Remove the specimen, wipe off the surface moisture, and weigh it again. If the mass of the same volume of water in the wax-sealed specimen increases, the test should be repeated.

[0013] Step 6: Calculate the density of the rock block. The weighing in the test should be accurate to 0.01g, and the density value should be accurate to 0.01g.

[0014] As a further description of the above technical solution: the wet density and dry density of the rock block are calculated according to the following formulas:

[0015]

[0016]

[0017] In the formula:

[0018] ρ—Wet density of rock mass (g / cm³) 3 );

[0019] ρ d —Dry density of rock mass (g / cm³) 3 );

[0020] m—Wet specimen mass (g);

[0021] m1—mass of the wax-sealed specimen (g);

[0022] m3 — the mass (g) of water of the same volume as the wax-sealed specimen, i.e. the stable reading (g) displayed on a regular balance when the wax-sealed specimen is suspended in water;

[0023] ρ w —Density of water (g / cm³) 3 );

[0024] ρ p —Density of wax (g / cm³) 3 );

[0025] m s —Mass of dried specimen (g).

[0026] As a further description of the above technical solution: the capacity of the open container capable of holding water is within the range of experimental use.

[0027] As a further description of the above technical solution: the dimensions of the open container capable of holding water meet the test requirements.

[0028] As a further description of the above technical solution: the ordinary balance can weigh wet specimens, dried specimens, and wax-sealed specimens, but cannot weigh in water.

[0029] As a further description of the above technical solution: the range of the ordinary balance conforms to the experimental usage range.

[0030] As a further description of the above technical solution: the accuracy of the ordinary balance is 0.01g.

[0031] Another problem to be solved by the present invention is to provide a test device for determining the density of rock blocks, including a support and a thin thread. An ordinary balance is set under the support, the thin thread is used to tie the specimen, an open container filled with water is set on the ordinary balance, and the thin thread can be tied to the bottom of the support.

[0032] As a further description of the above technical solution: the support includes a crossbar and two adjustable support rods, the top ends of the two support rods are respectively fixedly connected to the two ends of the crossbar, and the crossbar can hold the thin thread on the specimen.

[0033] Compared with the prior art, the advantages of this invention are:

[0034] I. The test results of this scheme are accurate, and the calculated rock density value is consistent with the value calculated according to the test procedure specified in the "Standard for Test Methods of Engineering Rock Mass" (GB / T 50266-2013).

[0035] Second, the detection and calculation methods in this scheme are relatively simple.

[0036] Third, the equipment used in this method is simple and saves economic costs. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the experimental device of the present invention.

[0038] Explanation of the labels in the diagram:

[0039] 1. Support; 11. Crossbar; 12. Support rod; 2. Ordinary balance; 3. Open container for holding water; 4. Thread. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] A test method for determining the density of a rock block includes the following steps:

[0043] Step 1: Take representative rocks and prepare them into test specimens. The test specimens should be rounded rock blocks with a side length of 40mm to 60mm. Weigh them. If measuring dry density, first bake the test specimens at 105℃ to 110℃ for 24 hours, then take them out and place them in a desiccator to cool to room temperature, and then weigh them.

[0044] Step 2: Tie a thin thread to the specimen and place it in molten wax at a temperature of about 60℃ for about 1 to 2 seconds to make the surface of the specimen evenly coated with a layer of wax film with a thickness of 0.5mm-1.5mm. If there are air bubbles in the wax film, puncture them with a hot needle and smooth them with wax. After cooling, weigh the wax-sealed specimen.

[0045] Step 3: Fill the beaker with an appropriate amount of water, wipe the water off the outside of the beaker, place it on a regular balance and weigh it, then tare it.

[0046] Step 4: Slowly place the wax-sealed specimen into the beaker, fix the thin thread on the specimen to the horizontal bar of the device so that the specimen is suspended in the water without touching the inner wall of the beaker and the water in the beaker does not overflow, and read the stable reading displayed on the ordinary balance to obtain the mass of the same volume of water as the wax-sealed specimen.

[0047] Step 5: Remove the specimen, wipe off the surface moisture, and weigh it again. If the mass of the same volume of water in the wax-sealed specimen increases, the test should be repeated.

[0048] Step 6: Calculate the density of the rock block. The weighing in the test should be accurate to 0.01g, and the density value should be accurate to 0.01g.

[0049] The wet density and dry density of the rock block are calculated according to the following formulas:

[0050]

[0051]

[0052] In the formula:

[0053] ρ—Wet density of rock mass (g / cm³) 3 );

[0054] ρ d —Dry density of rock mass (g / cm³) 3 );

[0055] m—Wet specimen mass (g);

[0056] m1—mass of the wax-sealed specimen (g);

[0057] m3 — the mass (g) of water of the same volume as the wax-sealed specimen, i.e. the stable reading (g) displayed on a regular balance when the wax-sealed specimen is suspended in water;

[0058] ρ w —Density of water (g / cm³) 3 );

[0059] ρ p —Density of wax (g / cm³) 3 );

[0060] m s —Mass of dried specimen (g).

[0061] In addition, the "Standard for Test Methods of Engineering Rock Mass" (GB / T 50266-2013) stipulates that clean water with a density of 1 g / cm³ must be used in the standard. 3 Based on the above formula, the formula for the wet density of rock blocks obtained by the wax-sealing method can be written as:

[0062]

[0063] or

[0064]

[0065] In the above formula:

[0066] V—Total volume of the wax-sealed specimen (cm³) 3 This value is equal to the stable reading (g) displayed on a regular balance when the wax-sealed specimen is suspended in water.

[0067] It should be noted that the wet specimen mass refers to the mass of the specimen weighed in its natural state. If the specimen is dried (as described in step one) and then weighed, it is the dried specimen mass.

[0068] Example 2

[0069] See also Example 1 Figure 1 It can be seen that the test apparatus for determining the density of rock blocks provided in this scheme includes a support 1, a thin thread 4, an ordinary balance 2 under the support 1, the thin thread 4 for tying the specimen, and an open container 3 (a beaker or other container can be used) for holding water on the ordinary balance 2. Figure 1The cup used in this case is a beaker, and the bottom of the support 1 can be tied with a thin thread 4.

[0070] The support 1 includes a crossbar 11 and two adjustable support rods 12. The top ends of the two support rods 12 are fixedly connected to the two ends of the crossbar 11 respectively. The thin thread 4 on the wax-sealed specimen is tied to the crossbar 11. By designing the support rods 12 to be adjustable, the height of the entire support 1 is adjustable, thereby allowing the wax-sealed specimen to float in the water without touching the inner wall of the cup and preventing the water in the cup from overflowing.

[0071] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solutions, principles, and improved concepts of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A test method for determining the density of a rock block, characterized in that: Includes the following steps: Step 1: Take representative rocks and prepare them into specimens. The specimens are rounded rock blocks with a side length of 40mm to 60mm. Weigh them. If measuring dry density, first bake the specimens at 105℃ to 110℃ for 24 hours, then take them out and place them in a desiccator to cool to room temperature, and then weigh them. Step 2: Tie a thin thread to the specimen and place it in molten wax at a temperature of about 60℃ for 1 to 2 seconds to make the surface of the specimen evenly coated with a layer of wax film with a thickness of 0.5 mm to 1.5 mm. If there are air bubbles in the wax film, puncture them with a hot needle and smooth them with wax. After cooling, weigh the wax-sealed specimen. Step 3: Fill an open container with an appropriate amount of water, wipe the surface of the container dry, weigh it on a regular balance, and then tare it. Step 4: Slowly place the wax-sealed specimen into an open container, fix the thin thread on the specimen to the horizontal bar of the device so that the specimen is suspended in the water without touching the inner wall of the container and the water in the container does not overflow. Read the stable reading displayed on the ordinary balance to obtain the mass of the same volume of water in the wax-sealed specimen. Step 5: Remove the specimen, wipe off the surface moisture, and weigh it again. When the mass of the same volume of water in the wax-sealed specimen increases, repeat the test. Step 6: Calculate the density of the rock block. The weighing in the experiment is accurate to 0.01g, and the density value is accurate to 0.01g.

2. The test method for determining the density of a rock block according to claim 1, characterized in that: The wet density and dry density of the rock block are calculated according to the following formulas: ； ； In the formula: ρ— Wet density of rock mass (g / cm³) 3 ); ρ d — Dry density of rock mass (g / cm³) 3 ); m— Wet specimen mass (g); m 1 — Mass of wax-sealed specimen (g); m 3 — The mass (g) of water of the same volume as the wax-sealed specimen, i.e. the stable reading (g) displayed on a regular balance when the wax-sealed specimen is suspended in water. ρ w — Density of water (g / cm³) 3 ); ρ p — density of wax (g / cm³) 3 ); ms— Mass of dried specimen (g).

3. The test method for determining the density of a rock block according to claim 1, characterized in that: The capacity of the open container that can hold water is within the range of test use.

4. The test method for determining the density of a rock block according to claim 1, characterized in that: The dimensions of the open container capable of holding water meet the requirements of the test.

5. The test method for determining the density of a rock block according to claim 1, characterized in that: The ordinary balance can weigh wet specimens, dried specimens, and wax-sealed specimens, but it cannot weigh specimens in water.

6. The test method for determining the density of a rock block according to claim 1, characterized in that: The range of the ordinary balance is within the range of test use.

7. The test method for determining the density of a rock block according to claim 1, characterized in that: The accuracy of the ordinary balance is 0.01g.

8. An apparatus for use in a method for determining the density of a rock block as described in any one of claims 1-7, characterized in that: Includes a support (1) and a thin line (4). A common balance (2) is set under the support (1). The thin line (4) is used to tie the test piece. An open container (3) that can hold water is set on the common balance (2). The thin line (4) can be tied to the bottom of the support (1). The bracket (1) includes a crossbar (11) and two adjustable support rods (12). The top ends of the two support rods (12) are fixedly connected to the two ends of the crossbar (11), and the thin line (4) is tied to the crossbar (11).

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