Consolidation test sample preparation device and method for earth-rock dam construction materials

Abstract

The present invention discloses a sample preparation device and method for the consolidation test of earth-rock dam filling materials, including a floating-ring consolidation container. A floating ring is provided inside the floating-ring consolidation container. After filling the sample in the floating ring, the sample is prepared by reacting against the floating ring through a reaction force device or by exciting the sample with a dual-machine frequency modulation vibrator. Among them, the reaction static pressure sample preparation method has no dust flying during the sample preparation process and avoids particle breakage to a greater extent. It is applicable to the low sample preparation density requirements of indoor consolidation tests and the filling materials for the dam that are easy to form samples. In the dual-machine frequency modulation vibrator excitation sample preparation method, frequency modulators are installed on the two vibration motors, which can enable the dual-machine frequency modulation vibrator to adjust the vibration frequency during the sample preparation process to avoid over-vibration or under-vibration of the sample. It is applicable to the high sample preparation density requirements of indoor consolidation tests and the filling materials for the dam that are not easy to form samples.

Description

Technical Field

[0001] The present invention belongs to the technical field of geotechnical tests for water conservancy and hydropower projects, and specifically relates to a sample preparation device for the consolidation test of earth-rock dam filling materials, and also relates to a sample preparation method for the consolidation test of earth-rock dam filling materials. Background Art

[0002] Earth-rock dams are widely used in the construction of water conservancy and hydropower projects. With the improvement of construction technology, the dam height of earth-rock dams has been significantly increased, its rolling technology has become more and more perfect, and the in-situ rolling density of the filling materials has been continuously improved. It is self-evident the necessity of studying the mechanical properties of the filling materials through indoor tests. Among them, the consolidation test can measure the relationship between the void ratio and pressure of the filling materials, calculate the compression coefficient, compression index, volume compression coefficient, compression modulus, consolidation coefficient and pre-consolidation pressure of the filling materials, which is of great significance for guiding the construction of earth-rock dam projects.

[0003] When conducting the consolidation test on the filling materials in the high-density state, due to the large size of the consolidation test specimens and the limitations of indoor space and technology, the conventional sample preparation methods often face the problem that the filling materials cannot reach the high-density state, and even the sample preparation density is far lower than the set value. On the other hand, the conventional sample preparation methods will generate a large amount of dust during the sample preparation process, which will pollute the indoor environment and endanger the health of the test personnel. When conducting the consolidation test on the filling materials in the low-density state, the conventional sample preparation methods often have the situation of over-vibrating the specimens, resulting in an increase in the density of the specimens and causing serious deviation of the test results. When the specimen composition is soft rock filling materials, the conventional sample preparation methods are extremely easy to cause the crushing of coarse particles in the specimens during the sample preparation process, changing the test gradation of the specimens and also causing serious deviation of the test results. The above problems have not been effectively solved in this field, and the present invention starts from the root of the test itself and solves the above problems through a new sample preparation method. Summary of the Invention

[0004] The purpose of the present invention is to provide a sample preparation device for the consolidation test of earth-rock dam filling materials, which solves the problem that the existing sample preparation methods often have the situation of over-vibrating the specimens or the coarse particles are easily broken during the sample preparation process, resulting in serious deviation of the test results.

[0005] The purpose of the present invention is also to provide a sample preparation method for the consolidation test of earth-rock dam filling materials.

[0006] The first technical solution adopted by the present invention is: a sample preparation device for the consolidation test of earth-rock dam filling materials, a floating-ring type consolidation container, a floating ring is arranged inside the floating-ring type consolidation container, and four lifting rings are fixedly connected to the outer circular box body of the floating-ring type consolidation container; after filling the specimen in the floating ring, sample preparation is carried out through a sample forming device.

[0007] In this solution, the sample forming device sets up a reaction force device by using the reaction force hydrostatic mechanism; the reaction force device includes a reaction force beam, and reaction force columns are threadedly connected to both ends of the reaction force beam; a pit is set on the ground, and a guide rail is laid on the ground above the pit. A pulley base is slidably arranged on the guide rail, and a circular groove is provided on the pulley base. The floating ring consolidation container is placed at the circular groove.

[0008] The reaction force columns are located outside the guide rail, and the reaction force columns are fixedly connected to the reaction force base. The reaction force base is located in the pit below the ground, and a jack is placed in the pit. The jack is placed at the central position above the reaction force base; a bearing plate a is movably arranged above the jack, and the floating ring consolidation container is located directly above the bearing plate a.

[0009] It also includes a circular bearing plate b. A longitudinal force transmission column is placed at the center of the circular bearing plate b, and the force transmission column is located directly below the reaction force beam.

[0010] The diameter of the circular bearing plate b is 2.0 mm smaller than the inner diameter of the floating ring.

[0011] The diameter of the circular groove is 2.0 mm larger than the outer diameter of the floating ring consolidation container.

[0012] The second technical solution adopted by the present invention is: a soil-rock dam filling material consolidation test sample forming device, a floating ring consolidation container. A floating ring is arranged inside the floating ring consolidation container, and four lifting rings are fixedly connected above the outside of the floating ring; after filling the sample in the floating ring, the sample is formed through the sample forming device.

[0013] In this solution, the sample forming device sets up a double-machine frequency modulation vibrator by using the vibration excitation mechanism; the double-machine frequency modulation vibrator includes a double vibration motor and a frequency modulator that are electrically connected; the double vibration motor is fixed on the steel plate base; four steel columns are welded below the steel plate base, and a circular steel plate a is welded below the steel columns. A stiffening triangular steel plate is also arranged between the steel columns and the circular steel plate a; the two right-angled sides of the stiffening triangular steel plate are respectively welded to the steel columns and the circular steel plate a.

[0014] It also includes a vibration excitation base. The vibration excitation base includes a steel plate b. Four groups of arc-shaped limit blocks are welded at the center of the steel plate b. The arc-shaped limit blocks are sequentially connected to form a circle with an inner diameter 2.0 mm larger than the outer diameter of the floating ring consolidation container, which fits with the outer circular box of the floating ring consolidation container.

[0015] The third technical solution adopted by the present invention is: a soil-rock dam filling material consolidation test sample forming method, which specifically includes the following steps:

[0016] Step 1. Hoisting of the floating ring consolidation container: The two ends of the two steel cables are respectively passed through the four lifting rings and fixed. The central positions of the two steel cables are respectively hung on the hooks of the special equipment overhead crane and hoisted into the circular groove of the pulley base.

[0017] Step 2. Specimen loading: Divide the test materials equally and load them into the floating ring layer by layer. After the static pressure of the upper layer of test materials is completed, load the lower layer of test materials for static pressure; after the test materials are loaded and the surface is leveled, place a circular bearing plate b with a diameter 2.0 mm smaller than the inner diameter of the floating ring above the specimen to be statically pressed; the designed height of the specimen is denoted as h 0 , the height of the floating ring is denoted as h 1 , and h 0 <h 1 , the thickness of the circular bearing plate b is denoted as h 2 ; Measure the height from the upper surface of the circular bearing plate b to the top of the floating ring after each layer of test materials is loaded. When , the specimen needs to be statically pressed, and go to Step 3-4;

[0018] where n is the number of loading layers, taking the value of 1 for the first layer, 2 for the second layer, and so on;

[0019] Step 3. Specimen reaction static pressure: After Step 2 is completed, push the pulley base to move the floating ring consolidation container to the middle position of the reaction device. Place the circular bearing plate b on the specimen, and place the load transfer column at the center of the circular bearing plate b so that the load transfer column is directly below the reaction beam. Apply pressure with the jack to lift the floating ring consolidation container and the pulley base as a whole. The load transfer column contacts the lower part of the reaction beam to generate reaction force;

[0020] Step 4. Specimen forming: Under the action of the reaction force, the specimen is compressed. Use a steel ruler to measure the height from the upper surface of the circular bearing plate b to the top of the floating ring (2) in real time. Calculate the height h 4 of the specimen after static pressure, that is h 4 = ; When h 4 = , stop static pressure, where n is the number of loading layers, taking the value of 1 for the first layer, 2 for the second layer, and so on; Release the pressure of the jack to lower the floating ring consolidation container and the pulley base as a whole. The pulley base falls onto the guide rail, and then push it out of the reaction device to load the next layer of test materials;

[0021] Step 5: Layered filling of the test materials as described in Step 2. After the static pressure of the upper-layer test materials is completed, fill the lower-layer test materials and determine whether static pressure is required according to Step 2. When static pressure is required, repeat Steps 3 and 4 until the specimen preparation is completed.

[0022] The fourth technical solution adopted by the present invention is a method for preparing a specimen for the consolidation test of earth-rock dam filling materials, which specifically includes the following steps:

[0023] Step 1: Hoisting of the floating-ring consolidation container: Pass the two ends of the two steel cables through the four lifting rings respectively and fix them. Hang the central positions of the two steel cables on the hooks of the special equipment overhead crane and hoist them to the inside of the arc-shaped limit block;

[0024] Step 2: Specimen filling: Divide the test materials equally and fill them into the floating ring layer by layer. After the vibration of the upper-layer test materials is completed, fill the lower-layer test materials for vibration; the designed height of the specimen is denoted as h 0 , the height of the floating ring is denoted as h 1 , h 0 <h 1； After each layer of test materials is filled, level the surface and measure the height from the upper surface of the specimen to the top of the floating ring at this time h 2 . When , the specimen needs to be vibrated, and Steps 3-5 are executed; where n is the number of filling layers, taking the value of 1 for the first layer, 2 for the second layer, and so on;

[0025] Step 3: Calculate the vibration time: Calculate the exciting force according to the formulas F = mrw 2 and w= 2 πf , where F is the exciting force, m is the mass of the eccentric block of the vibrator, r is the distance between the centroid of the eccentric block and the axis of the rotating shaft, w is the angular frequency of the motor rotation, f is the operating frequency of the vibration motor; taking the requirement that when the exciting force of the vibrator is 4.20 kN and the vibration contact area of the specimen is 706.85 cm 2 in the relative density test of coarse-grained soil in the "Standard for Geotechnical Test Methods" GB / T 50123-2019, and the vibration time is 8.00 min to make the specimen reach the maximum dry density as the reference standard. After normalizing the exciting force acting on the specimen surface to the load, use the impulse theorem to calculate the vibration time of the specimen to be vibrated in the consolidation test;

[0026] Step 4, Specimen excitation: Hoist the dual-machine frequency-modulated vibrator into the floating ring so that the circular steel plate a is in full contact with the specimen surface, and adjust the frequency through the frequency modulator f to the set value, start the dual-machine frequency-modulated vibrator, and perform excitation in two time periods equally divided according to the time measured in Step 3;

[0027] Step 5, Specimen forming: After two time periods of excitation, measure the height from the upper surface of the circular steel plate a to the top of the floating ring h 3 , and record the thickness of the circular steel plate a as h 4 , calculate the height of the specimen after the excitation is completed as h 5 , h 5 = h 1 - h 3 -h 4 , when h 5 = , stop the excitation, where n is the number of filling layers, taking the value of 1 for the first layer, 2 for the second layer, and so on; Hoist the dual-machine frequency-modulated vibrator out of the floating ring and perform the filling of the test materials for the next layer;

[0028] Step 6, As described in Step 2, the test materials are filled in layers. After the excitation of the test materials in the upper layer is completed, fill the test materials in the lower layer, and judge whether excitation is required according to Step 2. When excitation is required, repeat Step 3, Step 4, and Step 5 until the specimen preparation is completed.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] (1) For the dam building materials with low sample preparation density requirements and easy sample formation in the indoor consolidation test, the reaction force static pressure sample formation method is used for sample preparation. During the sample preparation process, there is no dust, and particle breakage is avoided to a greater extent. Compared with the traditional vibrator method, it has the advantages of environmental protection and protecting the sample gradation.

[0031] (2) For the dam building materials with high sample preparation density requirements and difficult sample formation in the indoor consolidation test, the dual-machine frequency-modulated vibrator excitation sample formation method is used. During the sample preparation process of the dual-machine frequency-modulated vibrator, the excitation frequency is adjusted through the frequency modulator and excitation is performed in two equally divided time periods, which can avoid over-excitation or under-excitation of the specimen. At the same time, the floating ring type consolidation container is limited and fixed by the excitation base, and the floating ring type consolidation container is not easy to deviate during excitation, ensuring the safety of the test personnel during the sample preparation process.

[0032] The two sample preparation methods provided by the present invention meet different sample preparation requirements, have a simple structure and are convenient to assemble; they are very suitable for the sample preparation requirements of consolidation tests. Description of the Drawings

[0033] For the convenience of those skilled in the art to understand, the present invention will be further described below in conjunction with the drawings.

[0034] Figure 1 It is a schematic diagram of the appearance of the floating ring type consolidation container and the reaction force device in the present invention.

[0035] Figure 2 It is a sectional view of the floating ring type consolidation container and the reaction force device in the present invention.

[0036] Figure 3 It is a schematic diagram of the double-machine frequency modulation vibrator in the present invention.

[0037] Figure 4 It is a schematic diagram of the excitation base in the present invention.

[0038] In the figure: 1. Floating ring type consolidation container; 2. Floating ring; 3. Suspension ring; 4. Reaction force device; 5. Reaction force beam; 6. Reaction force column; 7. Ground; 8. Guide rail; 9. Pulley base; 10. Jack; 11. Reaction force base; 12. Bearing plate a; 13. Circular bearing plate b; 14. Force transfer column; 15. Double-machine frequency modulation vibrator; 16. Stiffening triangular steel plate; 17. Frequency modulation device; 18. Double vibration motors; 19. Steel plate base; 20. Steel column; 21. Circular steel plate a; 22. Arc-shaped limit block; 23. Excitation base; 24. Steel plate b. Detailed Embodiments

[0039] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0040] Embodiment 1

[0041] The present invention includes a floating ring type consolidation container 1, a floating ring 2 is arranged inside the floating ring type consolidation container 1, and four suspension rings 3 are fixedly connected to the outer circular box body of the floating ring type consolidation container 1; after filling the sample in the floating ring 2, static sample preparation is carried out by the reaction force of the reaction force device 4.

[0042] According to Figure 1 and Figure 2As shown in the figure, the reaction force device 4 includes a reaction force beam 5, and reaction force columns 6 are threadedly connected to both ends of the reaction force beam 5; a pit is provided on the ground 7, and a guide rail 8 is laid on the ground 7 above the pit. The reaction force columns 6 are located outside the guide rail 8; a pulley base 9 is slidably connected to the guide rail 8, and a circular groove is provided on the pulley base 9. The floating ring type consolidation container 1 is placed at the circular groove. A jack 10 is placed in the pit, and a bearing plate a 12 is movably arranged above the jack 10. The floating ring type consolidation container 1 is located directly above the bearing plate a 12; the reaction force columns 6 are fixedly connected to a reaction force base 11, and the reaction force base 11 is located in the pit below the ground 7, and the jack 10 is placed at the center position above the reaction force base 11.

[0043] The outer diameter of the floating ring type consolidation container is 69.5 cm, the inner diameter of the floating ring is 50.5 cm, and the height of the floating ring is 30.0 cm.

[0044] Example 2

[0045] During actual use, first level and tamp the ground, and dig a pit of 1.0 m × 1.0 m × 0.8 m at the leveled ground and perform hardening treatment. A reaction force base is arranged in the pit and fixed on the hardened ground of the pit. Reaction force columns are fixedly installed on the reaction force base. The inner distance between the two reaction force columns is 72.0 cm. After the reaction force columns are installed, a reaction force beam is fixedly installed by threading at the top of the reaction force columns, and the height of the reaction force beam from the ground can be adjusted by threading. Guide rails are installed in parallel on the ground inside the reaction force columns. The width of the guide rail is 5.0 cm, and the inner distance between the two guide rails is 58.0 cm. A pulley base is placed above the guide rail. Four pulleys are installed on the bottom surface of the base and can roll forward or backward on the guide rail. The top surface of the pulley base is a square with a side length of 70.0 cm, and there is a circular limiting groove on the top surface with a diameter of 69.7 cm. A 100t jack is placed at the middle position of the reaction force base, and a rigid bearing plate a is placed above the jack. When the top surface of the bearing plate a is stressed, it contacts the bottom surface of the pulley base, causing the pulley base and the floating ring type consolidation container above it to lift.

[0046] Example 3

[0047] Assume that the dry density of the sample prepared for the consolidation test is 2.00 g / cm 3 , and it is less than the maximum dry density of the sample; according to the floating ring size, the sample diameter is determined to be 50.5 cm, and the designed height of the sample is 28.0 cm. Based on this, the sample material consumption is calculated to be 112.17 kg. The test materials are divided into 4 equal parts and filled in layers. After the sample of the upper layer of test materials is prepared, the lower layer of test materials is filled. The designed height of each layer is 7.0 cm. The method of preparing the sample by reaction force static pressure includes the following steps:

[0048] Step 1. Hoisting of the floating-ring consolidation container: Pass the two ends of two steel cables through the four lifting rings of the floating-ring consolidation container respectively and fix them. Hang the central positions of the two steel cables on the hooks of the special equipment overhead crane, start the crane for hoisting to the pulley base, and adjust the position of the floating-ring consolidation container in real time during hoisting to make it fall into the circular groove on the top surface of the pulley base.

[0049] Step 2. Sample filling: The designed height of the sample is 28.0 cm, and the height of the floating ring is 30.0 cm, and 28.0 cm < 30.0 cm holds. Divide the test materials into 4 equal parts and fill them in layers. After the static pressure of the upper-layer test materials is completed, fill the lower-layer test materials. First, fill the first layer of test materials into the floating ring and level the surface, and place the circular bearing plate b13 above the sample. Measure the height from the upper surface of the circular bearing plate b13 to the top of the floating ring at this time as 20.0 cm. According to the formula, calculate that the height of the sample at this time is 8.0 cm, which is greater than the layered design height of 7.0 cm, so the sample needs static pressure.

[0050] Step 3. Static pressure of the sample: After the content of Step 2 is completed, push the pulley base to move the floating-ring consolidation container to the middle position of the reaction device. Place the load transfer column 14 at the center on the circular bearing plate b13, making the load transfer column 14 slightly lower than the lower part of the reaction beam. Apply pressure with the jack to lift the floating-ring consolidation container and the pulley base as a whole, and the load transfer column 14 contacts the lower part of the reaction beam to generate a reaction force.

[0051] Step 4. Sample forming: Under the action of the reaction force, the sample is compressed. Use a steel ruler to measure the height from the upper surface of the circular bearing plate b13 to the top of the floating ring at 4 equally spaced positions along the inner wall of the floating ring in real time and calculate its average value. During the static pressure process, when it is calculated that the height of the layered sample after static pressure is still greater than 7.0 cm, the static pressure time needs to be extended or the static pressure reaction force needs to be increased; when it is calculated that the height of the layered sample after static pressure is equal to 7.0 cm to meet the sample layer height, stop the static pressure.

[0052] After the static pressure stops, the jack is depressurized to lower the floating-ring consolidation container and the pulley base as a whole, and the base pulley falls onto the guide rail. Then, push it out of the reaction device and fill the next layer of test materials.

[0053] Step 5. As described in Step 2, the test materials are filled in four layers. After the static pressure of the upper-layer test materials is completed, fill the next layer of test materials, and judge whether static pressure is required according to Step 2. When static pressure is required, repeat Step 3 and Step 4 until the sample preparation is completed.

[0054] Example 4

[0055] The sample preparation device for the consolidation test of the earth-rock dam filling material of the present invention includes a floating ring type consolidation container 1. A floating ring 2 is arranged inside the floating ring type consolidation container 1. After filling the sample in the floating ring 2, vibration excitation is carried out by using a vibration excitation mechanism for sample preparation; four lifting rings 3 are fixedly connected to the outer circular box body of the floating ring type consolidation container 1; as Figure 3 shown, in this solution, a dual-machine frequency modulation vibrator 15 is used for vibration excitation sample preparation. The dual-machine frequency modulation vibrator 15 includes a dual-vibration motor 18 and a frequency modulator 17 which are electrically connected; the dual-vibration motor 18 is fixed on a steel plate base 19; four steel columns 20 are welded below the steel plate base 19, and a circular steel plate a21 is welded below the steel columns 20. A stiffening triangular steel plate 16 is also arranged between the steel columns 20 and the circular steel plate a21; the two right-angled sides of the stiffening triangular steel plate 16 are respectively welded to the steel columns 20 and the circular steel plate a21. The stiffening triangular steel plate 16 plays a stabilizing role to prevent the four steel columns from bending and deforming during vibration excitation. A frequency modulator 17 is installed on the power line of the dual-vibration motor 18 to adjust the vibration excitation frequency of the dual-machine frequency modulation vibrator, and the adjustment range of the frequency is 0 - 30 Hz.

[0056] Example 5

[0057] On the basis of Example 4,

[0058] The sample preparation device for the consolidation test of the earth-rock dam filling material of the present invention, as Figure 4 shown, further includes a vibration excitation base 23. The vibration excitation base 23 includes a steel plate b24 with a thickness of 3.0 cm and a diameter of 1.5 m. Four groups of arc-shaped limiting blocks 22 are welded at the center of the steel plate b24. They can be connected in sequence to form a circle with an inner diameter of 69.7 cm, which fits with the outer circular box body of the floating ring type consolidation container.

[0059] Example 6

[0060] Assume that the dry density of the test is 2.20 g / cm 3 , and it is equal to the maximum dry density. According to the floating ring size, the sample diameter is determined to be 50.5 cm, and the designed height of the sample is 28.0 cm. Based on this, the sample material consumption is calculated to be 123.38 kg. The test materials are equally divided into 4 parts and filled in layers. After the sample preparation of the upper layer of test materials is completed, the lower layer of test materials is filled. The designed height of each layer is 7.0 cm. Using the device of Example 5, the sample preparation is carried out by the dual-machine frequency modulation vibration excitation method, which includes the following steps:

[0061] Step 1: Hoisting of the floating ring type consolidation container: The two ends of two steel cables are respectively passed through the four lifting rings of the floating ring type consolidation container and fixed. The central positions of the two steel cables are respectively hung on the hooks of the special equipment overhead crane. Start the crane for hoisting. During the hoisting process, the position of the floating ring type consolidation container is adjusted in real time to make it fall within the limiting blocks of the vibration excitation base.

[0062] Step 2. Specimen filling: The designed height of the specimen is 28.0 cm, and the height of the floating ring is 30.0 cm, and 28.0 cm < 30.0 cm holds. Divide the test materials into 4 equal parts and fill them in layers. After the vibration of the upper-layer test materials is completed, fill the lower-layer test materials. Fill the first-layer test materials into the floating ring and level the surface. The height from the top of the specimen to the top of the floating ring is measured to be 19.0 cm, and the calculated specimen height is 9.0 cm, which is greater than the stratified design height of 7.0 cm. The required compression of the specimen is 2.0 cm, and the specimen needs to be vibrated.

[0063] Step 3. Measuring and calculating the vibration time: According to the formula F = mrw 2 and w= 2 πf calculate the exciting force, where F is the exciting force (N), m is the mass of the eccentric block of the vibrator (kg), r is the distance between the centroid of the eccentric block and the axis of the rotating shaft (m), w is the angular frequency of the motor rotation, f is the operating frequency of the vibration motor. In the relative density test of coarse-grained soil, the exciting force of the vibrator is 4.20 kN, the vibration contact area of the specimen is 706.85 cm 2 , and the vibration time of 8.00 min can meet the requirement of the maximum dry density of the specimen;

[0064] Taking this as a reference standard, after normalizing the exciting force acting on the specimen surface into load, use the impulse theorem to measure and calculate the vibration time of the stratified specimen in the consolidation test. According to the above requirements, the calculated times corresponding to different exciting frequencies are shown in Table 1 below:

[0065] Table 1. Corresponding table of exciting frequency - time

[0066]

[0067] Step 4. Specimen vibration: After the content of Step 2 is completed, hoist the double-machine frequency-modulated vibrator into the floating ring to make the circular steel plate a21 fully contact with the specimen surface, and adjust the exciting frequency f to the set value, start the vibrator, and vibrate in two time periods with reference to the time measured in Step 3.

[0068] After the first-layer specimen is vibrated for one time period, when the compression of the specimen is greater than 1.0 cm, the exciting frequency needs to be reduced in the next time period; when it is less than 1.0 cm, the exciting frequency needs to be increased in the next time period; when it is equal to 1.0 cm, the exciting frequency can be maintained and the next time period of vibration can be directly carried out. For the subsequent stratified specimens, the exciting frequency of the next time period is also adjusted according to the size relationship between the actual compression of each time period and the required compression of each time period.

[0069] Step 5, sample forming: After the vibration excitation in two periods is completed, use a steel ruler to measure the height from the upper surface of the circular steel plate a21 to the top of the floating ring at 4 equally spaced positions along the inner wall of the floating ring in real time. If the height of the stratified sample after vibration excitation is still greater than 7.0 cm through calculation, then according to the required recompression amount of the sample, increase the vibration excitation frequency, and continue the vibration excitation in two periods with reference to the time measured in Step 3. When the calculated height of the stratified sample after vibration excitation is equal to 7.0 cm, meeting the designed height of the sample stratification, stop the vibration excitation. Lift the dual-machine frequency-modulated vibrator out of the floating ring and load the test materials for the next layer.

[0070] Step 6, as described in Step 2, load the test materials in four layers. After the vibration excitation of the test materials in the upper layer is completed, load the test materials in the lower layer, determine the required compression amount of the test materials in this layer according to Step 2 and judge whether vibration excitation is needed. When vibration excitation is needed, refer to the vibration excitation frequency - time correspondence table in Step 3, and repeat Steps 4 and 5 until the sample preparation is completed.

[0071] As mentioned above, these are only the preferred embodiments of the present invention. The present invention will not be limited to these embodiments shown in this article, but rather conform to the broadest scope consistent with the principles and novel features disclosed in this article. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. Sample preparation method for consolidation test of earth-rock dam materials, characterized by: A sample preparation device for a consolidation test of earth-rock dam materials is used, comprising a floating ring type consolidation container (1), wherein a floating ring (2) is provided inside the floating ring type consolidation container (1), and after a sample is filled in the floating ring (2), the sample is prepared by a sample preparation device; four hanging rings (3) are fixedly connected to the outer circular box of the floating ring type consolidation container (1); The sample forming device uses an excitation mechanism to set up a dual-machine frequency-modulated vibrator (15), and the dual-machine frequency-modulated vibrator (15) includes a dual vibration motor (18) and a frequency modulator (17) that are electrically connected; the dual vibration motor (18) is fixed on a steel plate base (19); four steel columns (20) are welded below the steel plate base (19), and a circular steel plate a (21) is welded below the steel columns (20); a stiffening triangular steel plate (16) is also provided between the steel columns (20) and the circular steel plate a (21); two right-angled sides of the stiffening triangular steel plate (16) are respectively welded to the steel columns (20) and the circular steel plate a (21); It also includes a vibration base (23), the vibration base (23) includes a steel plate b (24), four groups of arc-shaped limit blocks (22) are welded at the center of the steel plate b (24), the arc-shaped limit blocks (22) are connected in sequence to form a circle with an inner diameter greater than the outer diameter of the floating ring consolidation container (1) by 2.0 mm, and fits with the outer circular box of the floating ring consolidation container (1); The specific steps are as follows: Step 1, hoisting of the floating ring type consolidation container: pass the two ends of the two steel cables through the four hoisting rings (3) respectively and fix them, hang the center positions of the two steel cables on the hooks of the special equipment crane respectively, and hoist them to the inner side of the arc-shaped limit block (22); Step 2, sample filling: Divide the test material into equal parts and fill them into the floating ring (2) in layers. After the vibration of the previous layer of test material is completed, the next layer of test material is filled and vibrated. The design height of the sample is recorded as h 0, the height of the floating ring is recorded as h 1, h 0 <h 1. After each layer of test material is filled, level the surface and measure the height from the surface above the sample to the top of the floating ring (2). h 2. When When the sample needs to be excited, execute steps 3-5; n is the number of loading layers, the value is 1 for the first layer, 2 for the second layer, and so on; Step 3: Calculate the excitation time: According to the formula F=mrw 2 and w= 2 πf Calculate the exciting force, where F For the exciting force, m is the mass of the vibrator eccentric block, r is the distance between the center of mass of the eccentric block and the center of rotation axis, w is the motor rotation angular frequency, f is the operating frequency of the vibration motor; after normalizing the exciting force acting on the sample surface to the load, the impulse theorem is used to calculate the excitation time of the sample in the consolidation test to be excited layer; Step 4: Sample excitation: hoist the dual frequency modulated vibrator (15) into the floating ring (2), so that the circular steel plate a (21) is in full contact with the sample surface, and adjust the frequency through the frequency modulator (17). f To the set value, start the dual frequency modulated vibrator, and vibrate in two equal periods according to the time calculated in step 3; Step 5: Sample forming: After two periods of vibration, measure the height from the upper surface of the circular steel plate a (21) to the top of the floating ring. h 3. The thickness of the circular steel plate a (21) is recorded as h 4. Calculate the sample height after vibration is completed h 5. h 5 = h 1 - h 3 -h 4. When h 5= When the excitation stops, n is the number of loading layers, the first layer is 1, the second layer is 2, and so on; the dual-machine frequency modulation vibrator (15) is hoisted out from the floating ring, and the next layer of test materials is loaded; Step 6. Load the test materials in layers as described in step 2. After the vibration of the previous layer of test materials is completed, load the next layer of test materials and determine whether vibration is required according to step 2. If vibration is required, repeat steps 3, 4 and 5 until the sample preparation is completed.

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