Automatic disturbed soil layering sample preparation device and method based on power-off limiter

Abstract

The invention belongs to the technical field of geotechnical tests, and particularly relates to an automatic disturbed soil layering sample preparation device and method based on a power-off limiter. The combined sample preparation barrel is movably arranged on the bearing frame module; the compaction sample preparation module is mounted at the upper part of the bearing frame module, the compaction sample preparation module is provided with a vertically moving pressure head, and the pressure head is used for compacting the soil sample filled in the combined sample preparation barrel; the demolding module is installed on the lower portion of the bearing frame module and comprises a tray, the tray is elastically arranged in the bearing frame module through a plurality of springs, and after the combined type sample preparation barrel with the compacted soil sample is moved to the position above the tray, a pressing head ejects the soil sample in the combined type sample preparation barrel to the tray so as to take out the soil sample; and the limiting module is installed on the bearing frame module and controls a pressing head to conduct accurate layering compaction through a contact type power-off limiting device. The whole device is simple in structure and high in automation degree, and the test precision and efficiency can be greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical testing, and in particular relates to an automatic layered sample preparation device and method for disturbed soil based on a power-off limiter. Background Art

[0002] Preparation of disturbed soil samples is a basic technique in the field of soil mechanics research. In geotechnical laboratory tests, the process of preparing disturbed soil samples usually involves two independent steps: sample preparation and demoulding. These steps often need to be performed sequentially on different equipment. Laboratory staff need to transfer soil samples between different equipment instead of using an integrated device, which lacks the convenience of an integrated device.

[0003] The reliability of geotechnical test results depends largely on the accuracy of soil sample preparation. In engineering practice, disturbed soil samples can be prepared by the sample striking method, compaction method and compression method. Among them, the compression method is more commonly used in geotechnical tests due to its advantages such as simple operation, short sample preparation cycle and easy control of sample uniformity. The impact load of the sample striking method may affect the uniformity and mechanical properties of the soil sample. Although the compaction method avoids the impact load, the operation is complicated and may affect the soil sample due to uneven pressure. Overall, the compression method is superior to the sample striking method and compaction method in maintaining the soil sample structure and reducing disturbance, but overpressure and underpressure during compression will affect the quality of the soil sample and the accuracy of the test results.

[0004] Demolding is the last step in the preparation of disturbed soil samples. The accuracy and caution of the demolding step are very important to ensure the validity of the experimental results. The demolding of disturbed soil samples generally adopts the manual direct knocking demolding method and the electric demolding test machine demolding method. However, both demolding methods have their limitations. Specifically, the manual direct knocking demolding method is inefficient and has a low qualified rate of finished products; the electric demolding test machine demolding method has a large device size and a single function limitation, complex operation, high manpower and material costs for demolding, and low efficiency.

[0005] Therefore, it is of great practical significance and practical value to develop an automated sample preparation device and method for disturbed samples that integrates sample preparation and demoulding functions and can accurately compact by layers and demould quickly and efficiently. Summary of the invention

[0006] The purpose of the present invention is to provide a disturbed soil automatic stratified sampling device and method based on a power-off limiter to solve the above-mentioned problems.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] An automatic layered sample preparation device for disturbed soil based on a power-off limiter, comprising:

[0009] Load-bearing frame module;

[0010] A combined sample preparation cylinder, movably arranged on the carrying frame module;

[0011] A compaction sample preparation module is installed on the upper part of the load-bearing frame module, and the compaction sample preparation module is provided with a vertically movable pressure head, and the pressure head is used to compact the soil sample filled in the combined sample preparation cylinder;

[0012] A demoulding module is installed at the lower part of the load-bearing frame module. The demoulding module includes a tray. The tray is elastically arranged in the load-bearing frame module through a plurality of springs. After the combined sample preparation cylinder with the compacted soil sample is moved above the tray, the pressure head pushes the soil sample in the combined sample preparation cylinder onto the tray to take out the soil sample;

[0013] A limit module is installed on the bearing frame module and is used to control the displacement distance of the pressure head.

[0014] Optionally, the load-bearing frame module includes:

[0015] A base bottom plate, a partition middle plate and a reaction top plate are fixedly connected, wherein a gap is provided between the base bottom plate and the partition middle plate, and a gap is provided between the partition middle plate and the reaction top plate;

[0016] A demoulding hole is provided in the middle of the partition middle plate;

[0017] A translation module, used for horizontal movement of the combined sample preparation cylinder, wherein the fixed end of the translation module is fixedly connected to the partition middle plate;

[0018] The limiting module is installed on the partition middle plate.

[0019] The four corners of the reaction top plate are provided with through holes, the four corners of the partition middle plate are provided with support rod mounting holes, the four corners of the base bottom plate are provided with support rod threaded holes, the bottom end of the threaded support rod is threadedly connected to the threaded support rod in the support rod threaded hole, and the top end of the threaded support rod passes through the support rod mounting hole and the through holes in sequence;

[0020] Four hexagonal bolts are threadedly connected to the threaded support rod, two of the hexagonal bolts are respectively arranged at the top and bottom of the partition middle plate, and another two of the hexagonal bolts are respectively arranged at the top and bottom of the reaction top plate, and the two hexagonal bolts clamp and fix the reaction top plate or the partition middle plate.

[0021] Optionally, the translation module includes two horizontal telescopic slide rails, the fixed ends of the horizontal telescopic slide rails are fixedly connected to the top surface of the partition middle plate, the two horizontal telescopic slide rails are symmetrically arranged on both sides of the demoulding hole, the movable ends of the horizontal telescopic slide rails are fixedly connected to light telescopic support rods, and the light telescopic support rods are vertical to the horizontal telescopic slide rails;

[0022] The two horizontal telescopic slide rails are slidably connected to the bottom of the same sliding steel plate, a limiting ring groove is provided in the middle of the sliding steel plate, a limiting steel ring is limitedly matched in the limiting ring groove, and a slide rail limiting groove is provided at the bottom of the sliding steel plate for slidingly matching with the horizontal telescopic slide rail.

[0023] Optionally, the limit module includes:

[0024] A telescopic limiting pillar, wherein the bottom end of the telescopic limiting pillar is fixedly connected to the partition middle plate, a plurality of rotation limiting sleeves are movably arranged in the middle of the telescopic limiting pillar, the inner side of the rotation limiting sleeves vertically slides with the telescopic limiting pillar through a plurality of surrounding balls, a fixing bolt is threadedly connected to the side wall of the rotation limiting sleeve, and the fixing bolt is frictionally matched with the side wall of the telescopic limiting pillar to fix the rotation limiting sleeve to the telescopic limiting pillar; the top of the telescopic limiting pillar contacts the bottom of the reaction force top plate;

[0025] An annular slide rail is arranged on the outer side of the rotation limiting sleeve, a power-off limiter is slidably connected in the annular slide rail, and the power-off limiter can contact a metal limiting contact piece, and the metal limiting contact piece is fixedly connected to one side of the pressure head.

[0026] The bottom end of the telescopic limiting support is axially connected to a limiting support threaded rod, the limiting support threaded rod is threadedly connected to a limiting support threaded groove, and the limiting support threaded groove is arranged in the middle of the partition middle plate.

[0027] The top end of the telescopic limiting support pillar is axially connected with a cylindrical support foot, and the top of the cylindrical support foot is in contact with the bottom of the reaction force top plate.

[0028] Optionally, the compaction sample preparation module includes:

[0029] A multifunctional servo motor, the fixed end of which is fixedly connected to the reaction force top plate, the telescopic end of the multifunctional servo motor passes through the reaction force top plate axis and is connected to the top end of a compression rod, the bottom end of the compression rod is fixedly connected to the pressure head, and one side of the middle part of the compression rod is fixedly connected to one end of the metal limit contact piece.

[0030] A compression rod thread groove is formed at the top of the compression rod and is threadedly connected to the telescopic end of the multifunctional servo motor; a compression rod thread rod is formed at the bottom of the compression rod and is threadedly connected to the pressure head; a contact piece thread groove is formed on one side of the middle part of the compression rod and is threadedly connected to the metal limit contact piece.

[0031] Optionally, the tray of the demoulding module is located below the partition middle plate, the tray is elastically connected to the base bottom plate through a plurality of springs, and the tray is limitedly matched with the base bottom plate after being pressed down;

[0032] The demoulding module also includes a demoulding steel ring, which is installed in the demoulding hole and is limitedly matched with the demoulding hole.

[0033] Optionally, a plurality of spring thread grooves arranged in a matrix are formed on the base bottom plate, a spring thread rod is connected to the spring bottom axis, and the spring thread rod is threadedly connected to the spring thread grooves.

[0034] Optionally, telescopic self-locking support rods are fixedly connected to the front and rear sides of the bottom of the tray respectively, and the telescopic self-locking support rods are limited by self-locking buckles, and the self-locking buckles are fixedly connected to the base bottom plate.

[0035] A method for automated stratified sampling of disturbed soil, using the above-mentioned automated stratified sampling device for disturbed soil based on a power-off limiter, comprises the following steps:

[0036] Prepare disturbed soil;

[0037] Assembling equipment to movably mount the combined sample preparation cylinder on the load-bearing frame module;

[0038] Filling the first layer of disturbed soil in the combined sample preparation cylinder, and using the compaction sample preparation module to make the pressure head compact the disturbed soil, then moving the combined sample preparation cylinder out to fill the second layer of disturbed soil, and then compacting, repeating this step until all soil layers are compacted;

[0039] Demolding, the pressure head pushes out the soil sample in the combined sample preparation cylinder and moves it to the tray, and a number of the springs are compressed until the sample is completely taken out, and then the sample is tightly covered with a plastic film to complete demoulding.

[0040] Optionally, the relationship between the number of springs and the weight of the prepared sample is expressed as follows:

[0041]

[0042] Where: N is the number of springs, a positive integer;

[0043] n—number of compaction layers;

[0044] h—the height of each layer when the sample is compacted;

[0045] m—mass of each layer of sample;

[0046] G—weight of the tray (41), G≥2nmg;

[0047] k—spring stiffness;

[0048] b—height of the tray (41);

[0049] xmax—maximum compression of the spring, x max ≥nh-2.

[0050] Compared with the prior art, the present invention has the following advantages and technical effects:

[0051] When in use, first prepare the disturbed soil, then assemble the equipment, and movably install the combined sample preparation cylinder on the load-bearing frame module; fill the first layer of disturbed soil in the combined sample preparation cylinder, and use the compaction sample preparation module to make the pressure head compact the disturbed soil. The limit module can control the displacement distance of the pressure head to prevent overpressure and underpressure. After the first layer of soil is compacted, the combined sample preparation cylinder is moved out to fill the second layer of disturbed soil, and then compacted again until all soil layers are compacted. After demolding, the pressure head pushes out the soil sample in the combined sample preparation cylinder and moves it to the tray. Several springs are compressed until the sample is completely taken out, and then the sample is tightly covered with a plastic film to complete demolding. This device integrates sample preparation and demolding functions, can accurately compact in layers, and demold quickly. The entire device has a simple structure and a high degree of automation, which can greatly improve the test accuracy and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0053] Figure 1 It is a schematic diagram of the structure of the present invention;

[0054] Figure 2 It is a schematic diagram of the structure of the partition middle plate with horizontal telescopic slide rails of the present invention;

[0055] Figure 3 This is a schematic diagram of the telescopic limiting support structure of the present invention;

[0056] Figure 4 This is a schematic diagram of the structure of the sliding steel plate of the present invention;

[0057] Figure 5 This is a schematic diagram of the basic floor structure of the present invention;

[0058] Figure 6 It is a schematic diagram of the telescopic rod structure of the present invention;

[0059] Figure 7 It is a schematic diagram of the spring structure of the present invention;

[0060] Figure 8 This is a schematic diagram of the structure of a medium-sized demoulding steel ring with ears according to the present invention;

[0061] Fig. 9 This is a schematic diagram of the structure of a small demoulding steel ring with ears according to the present invention;

[0062] Fig.10 This is a schematic diagram of the structure of a medium-sized limit steel ring with ears according to the present invention;

[0063] Fig.11 This is a schematic diagram of the structure of a small-sized limit steel ring with ears according to the present invention;

[0064] Among them, 11, telescopic limit pillar; 111, limit pillar threaded rod; 112, cylindrical support foot; 113, ball bearing; 12, rotation limit sleeve; 121, fixing bolt; 122, annular slide rail; 13, power-off limiter; 14, metal limit contact; 21, reaction top plate; 22, partition middle plate; 221, limit pillar thread groove; 222, support rod mounting hole; 223, demoulding hole; 23, base bottom plate; 231, spring thread groove; 232, support rod thread hole; 24, threaded support rod; 25, sliding steel plate; 251, limit ring groove; 252, slide rail limit groove; 26, horizontal telescopic slide rail; 27, lightweight telescopic support rod; 28, hexagonal bolt; 31, pressure head; 32, combined sample preparation cylinder; 33 , compression rod; 331, compression rod thread groove; 332, contact piece thread groove; 333, compression rod thread rod; 34, multi-function servo motor; 41, tray; 42, spring; 421, spring thread rod; 43, telescopic self-locking support rod; 44, self-locking buckle; 51, medium-sized stripping steel ring with ears; 511, medium-sized stripping steel ring hole with ears; 512, medium-sized stripping steel ring with ears; 52, small-sized stripping steel ring with ears; 521, small-sized stripping steel ring hole with ears; 522, small-sized stripping steel ring with ears; 53, medium-sized limiting steel ring with ears; 531, medium-sized limiting steel ring hole with ears; 532, medium-sized limiting steel ring with ears; 54, small limiting steel ring with ears; 541, small limiting steel ring hole with ears; 542, small limiting steel ring with ears. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0067] Reference Figures 1 to 11 The present invention discloses Figure 1 As shown, a disturbed soil automatic layered sampling device based on a power-off limiter comprises:

[0068] Load-bearing frame module;

[0069] The combined sample preparation cylinder 32 is movably arranged on the carrying frame module;

[0070] The compaction sample preparation module is installed on the upper part of the load-bearing frame module. The compaction sample preparation module is provided with a vertically movable pressure head 31, and the pressure head 31 is used to compact the soil sample filled in the combined sample preparation cylinder 32;

[0071] The demoulding module is installed at the lower part of the load-bearing frame module. The demoulding module includes a tray 41. The tray 41 is elastically arranged in the load-bearing frame module through a plurality of springs 42. After the combined sample preparation cylinder 32 with the compacted soil sample is moved above the tray 41, the pressure head 31 pushes the soil sample in the combined sample preparation cylinder 32 onto the tray 41 to take out the soil sample;

[0072] The limit module is installed on the bearing frame module and is used to control the displacement distance of the pressure head 31.

[0073] When in use, first prepare the disturbed soil, then assemble the equipment, and movably install the combined sample preparation tube 32 on the load-bearing frame module; fill the first layer of disturbed soil in the combined sample preparation tube 32, and use the compaction sample preparation module to make the pressure head 31 compact the disturbed soil. The limit module can control the displacement distance of the pressure head 31 to prevent overpressure. After the first layer of soil is compacted, the combined sample preparation tube 32 is moved out to fill the second layer of disturbed soil, and then compacted again until all soil layers are compacted and demolded, so that the pressure head 31 pushes out the soil sample in the combined sample preparation tube 32 and moves it to the tray 41. A number of springs 42 are compressed until the sample is completely taken out, and then the sample is tightly covered with a plastic film to complete demolding. This device integrates sample preparation and demolding functions, can accurately compact in layers, and quickly demold. The entire device has a simple structure and a high degree of automation, which can greatly improve the test accuracy and efficiency.

[0074] As an optional implementation, the load-bearing frame module includes:

[0075] A base bottom plate 23, a partition middle plate 22 and a reaction top plate 21 are fixedly connected, a gap is provided between the base bottom plate 23 and the partition middle plate 22, and a gap is provided between the partition middle plate 22 and the reaction top plate 21;

[0076] A demoulding hole 223 is provided in the middle of the partition middle plate 22;

[0077] A translation module, used for horizontal movement of the combined sample preparation tube 32, the fixed end of the translation module is fixedly connected to the partition middle plate 22;

[0078] The limiting module is installed on the partition middle plate 22 .

[0079] The four corners of the reaction top plate 21 are provided with through holes, the four corners of the partition middle plate 22 are provided with support rod mounting holes 222, the four corners of the base bottom plate 23 are provided with support rod threaded holes 232, the bottom end of the threaded support rod 24 is connected to the inner thread of the support rod threaded hole 232, and the top end of the threaded support rod 24 passes through the support rod mounting hole 222 and the through hole in sequence;

[0080] Four hexagonal bolts 28 are threadedly connected to the threaded support rod 24, two hexagonal bolts 28 are respectively set at the top and bottom of the partition middle plate 22, and another two hexagonal bolts 28 are respectively set at the top and bottom of the reaction top plate 21. The two hexagonal bolts 28 clamp and fix the reaction top plate 21 or the partition middle plate 22.

[0081] As an optional embodiment, the translation module includes two horizontal telescopic slide rails 26, the fixed ends of the horizontal telescopic slide rails 26 are fixedly connected to the top surface of the partition middle plate 22, the two horizontal telescopic slide rails 26 are symmetrically arranged on both sides of the demoulding hole 223, and the movable ends of the horizontal telescopic slide rails 26 are fixedly connected to lightweight telescopic support rods 27, and the lightweight telescopic support rods 27 are vertical to the horizontal telescopic slide rails 26 in space;

[0082] The two horizontal telescopic slide rails 26 are slidably connected to the bottom of the same sliding steel plate 25. A limiting ring groove 251 is opened in the middle of the sliding steel plate 25. A limiting steel ring is limited in the limiting ring groove 251. A slide rail limiting groove 252 is opened at the bottom of the sliding steel plate 25 for slidingly cooperating with the horizontal telescopic slide rail 26.

[0083] As an optional implementation, the limit module includes:

[0084] The telescopic limiting pillar 11, the bottom end of the telescopic limiting pillar 11 is fixedly connected to the partition middle plate 22, a plurality of rotating limiting sleeves 12 are movably arranged in the middle of the telescopic limiting pillar 11, the inner side of the rotating limiting sleeve 12 vertically slides with the telescopic limiting pillar 11 through a plurality of surrounding balls 113, the side wall of the rotating limiting sleeve 12 is threadedly connected with a fixing bolt 121, the fixing bolt 121 and the side wall of the telescopic limiting pillar 11 are frictionally matched to fix the rotating limiting sleeve 12 and the telescopic limiting pillar 11; the top of the telescopic limiting pillar 11 is in contact with the bottom of the reaction top plate 21;

[0085] The annular slide rail 122 is provided on the outer side of the rotation limiting sleeve 12 , and a power-off limiter 13 is slidably connected inside the annular slide rail 122 . The power-off limiter 13 can contact a metal limiting contact piece 14 , and the metal limiting contact piece 14 is fixedly connected to one side of the pressure head 31 .

[0086] The bottom end of the telescopic limiting support 11 is axially connected to the limiting support threaded rod 111 , and the limiting support threaded rod 111 is threadedly connected to the limiting support threaded groove 221 , and the limiting support threaded groove 221 is provided in the middle of the partition middle plate 22 .

[0087] A cylindrical support leg 112 is axially connected to the top end of the telescopic limiting support pillar 11 , and the top of the cylindrical support leg 112 contacts the bottom of the reaction top plate 21 .

[0088] As an optional embodiment, the compaction sample preparation module includes:

[0089] The multifunctional servo motor 34 has a fixed end fixedly connected to the reaction force top plate 21, and the telescopic end of the multifunctional servo motor 34 passes through the reaction force top plate 21 and is axially connected to the top end of the compression rod 33, the bottom end of the compression rod 33 is fixedly connected to the pressure head 31, and one side of the middle part of the compression rod 33 is fixedly connected to one end of the metal limit contact piece 14.

[0090] A compression rod thread groove 331 is formed at the top of the compression rod 33 and is threadedly connected to the telescopic end of the multifunctional servo motor 34; a compression rod thread rod 333 is formed at the bottom of the compression rod 33 and is threadedly connected to the pressure head 31; a contact piece thread groove 332 is formed on one side of the middle part of the compression rod 33 and is threadedly connected to the metal limit contact piece 14.

[0091] As an optional embodiment, the tray 41 of the demoulding module is located below the partition middle plate 22, and the tray 41 is elastically connected to the base bottom plate 23 through a plurality of springs 42. After the tray 41 is pressed down, it is limitedly matched with the base bottom plate 23;

[0092] The demoulding module also includes a demoulding steel ring, which is installed in the demoulding hole 223 and is limitedly matched with the demoulding hole 223.

[0093] As an optional implementation, a plurality of spring thread grooves 231 arranged in a matrix are provided on the base bottom plate 23 , a spring thread rod 421 is connected to the bottom axis of the spring 42 , and the spring thread rod 421 is threadedly connected to the spring thread groove 231 .

[0094] As an optional embodiment, telescopic self-locking support rods 43 are fixedly connected to the front and rear sides of the bottom of the tray 41 respectively. The telescopic self-locking support rods 43 are limited by self-locking buckles 44, and the self-locking buckles 44 are fixedly connected to the base bottom plate 23.

[0095] An automatic layered sample preparation device for disturbed soil based on a power-off limiter comprises a bearing frame module, a compaction sample preparation module and a demoulding module.

[0096] The bearing frame module includes a reaction top plate 21, a partition middle plate 22, a base bottom plate 23, threaded support rods 24 and hexagonal bolts 28; the reaction top plate 21, the partition middle plate 22 and the base bottom plate 23 are supported and connected by the hexagonal bolts 28, and the hexagonal bolts 28 are tightened.

[0097] The partition middle plate 22 is located between the reaction top plate 21 and the base bottom plate 23 . The partition middle plate 22 and the reaction top plate 21 can be moved up and down through the support rod mounting holes 222 on the partition middle plate 22 to adjust the height.

[0098] A demoulding hole 223 is provided at the center of the partition middle plate with a horizontal telescopic slide rail for installing a sample demoulding steel ring; two identical horizontal telescopic slide rails 26 are installed on both sides of the demoulding hole.

[0099] The size of the demoulding hole 223 on the partition middle plate 22 corresponds to the maximum size of 101mm commonly used in laboratories; a limiting pillar threaded groove 221 is provided on the right side of the demoulding hole on the partition middle plate 22 for installing the telescopic limiting pillar 11, and support rod mounting holes 222 are provided at the four corners of the partition middle plate 22 for connecting the threaded support rod 24.

[0100] The compaction sample preparation module includes a combined sample preparation cylinder 32 arranged between the partition middle plate and the reaction force top plate, a multifunctional servo motor 34, a contact-type power-off limit device (including a telescopic limit support 11, a rotating limit sleeve 12, a power-off limiter 13, and a metal limit contact 14), and a mobile sample pressing platform with a limit ring groove.

[0101] In this embodiment, the disturbed soil sample is selected and compacted in five layers.

[0102] The telescopic limiting pillar 11 is provided with 5 rotation limiting sleeves 12, each rotation limiting sleeve 12 is provided with a power-off limiter 13, and the inner ring of the rotation limiting sleeve 12 is provided with a ball 113, which has the function of vertical movement. The fixing bolt 121 can be used to fix the rotation limiting sleeve, and the rotation limiting sleeve 12 is provided with an annular slide rail 122. When the height of the rotation limiting sleeve 12 is fixed, the power-off limiter 13 can rotate around the annular slide rail 122;

[0103] The rotation function of the rotation limit shaft sleeve 12 is used to adjust the position of the power-off limiter 13. When it rotates to the same vertical line as the metal limit contact piece 14, the power-off limiter 13 will be able to contact the metal limit contact piece 14 to power off the multifunctional servo motor.

[0104] The telescopic limiting pillar 11 can be connected to the limiting pillar threaded groove 221 of the partition middle plate 22 through the limiting pillar threaded rod 111 at the bottom; the top end of the telescopic limiting pillar 11 can be raised and lowered manually, and the maximum installation height of the rotating limiting sleeve 12 is smaller than the telescopic part of the telescopic limiting pillar 11; a cylindrical support foot 112 is provided on the top of the telescopic limiting pillar 11, which contacts the reaction top plate 21, and the rotating limiting sleeve 12 can be inserted into the telescopic limiting pillar 11 through the cylindrical support foot 112.

[0105] After the metal limit contact piece 14 touches the power-off limiter 13, the multifunctional servo motor will be powered off immediately and the compaction will stop.

[0106] There are three sets of combined sample preparation tubes 32, corresponding to three standard samples commonly used in laboratories (39.1mm*80mm, 61.8mm*125mm and 101mm*200mm respectively), and each set of combined sample preparation tubes 32 has a different inner diameter.

[0107] The combined sample preparation tube 32 includes a plurality of sleeve steel rings, the number of which can be determined according to the number of layers when making disturbed soil; each sleeve steel ring has the same height and inner diameter, and each sleeve steel ring can be filled with disturbed soil.

[0108] Each sleeve steel ring is provided with slots at the top and bottom so as to be able to engage with each other.

[0109] The multifunctional servo motor 34 is installed at the center of the reaction top plate 21, and can control the compaction process according to the stress and strain.

[0110] A compression rod threaded rod 333 is provided at the lower end of the compression rod 33, which can be connected to pressure heads 31 of different sizes. The size of the pressure head 31 depends on the size of the sample to be prepared, and the diameter is 1 to 2 mm smaller than the inner diameter of the combined sample preparation cylinder. A contact piece threaded groove 332 is provided at the lower section of the compression rod 33 for installing the metal limit contact piece 14. The compression rod threaded groove 331 at the top can be connected to the multi-functional servo motor 34.

[0111] The movable sample pressing platform comprises a sliding steel plate 25 with a limiting ring groove, a horizontal telescopic slide rail 26 and a light telescopic support rod 27.

[0112] There are two slide rail limiting grooves 252 on both sides below the sliding steel plate 25, which are adapted to the horizontal telescopic slide rail 26 that separates the middle plate 22. There is a limiting ring groove 251 in the middle for installing the sample limiting steel ring.

[0113] The size of the limiting ring groove 251 on the sliding steel plate 25 corresponds to the maximum size 101 mm commonly used in laboratories.

[0114] The demoulding module includes a tray 41 , a spring 42 , a telescopic self-locking support rod 43 , and a self-locking buckle 44 , which are arranged between the partition middle plate and the base bottom plate.

[0115] There are 16 spring thread grooves 231 distributed on the base bottom plate 23, and the size corresponds to the spring thread rod 421. The number of springs is calculated according to the weight of the prepared sample using the above formula, and the spring installation positions are reasonably allocated.

[0116] The sample demoulding steel rings include a medium-sized demoulding steel ring with ears 51 (corresponding to the laboratory standard sample size of 61.8 mm) and a small-sized demoulding steel ring with ears 52 (corresponding to the laboratory standard sample size of 39.1 mm). The outer diameter of the ear 512 of the medium-sized demoulding steel ring with ears is 1 cm larger than the inner diameter, the inner diameter of the hole 511 of the medium-sized demoulding steel ring with ears is the same as the inner diameter of the combined sample preparation tube 32, and the height of the medium-sized demoulding steel ring with ears is equal to the thickness of the partition middle plate; the outer diameter of the ear 522 of the small-sized demoulding steel ring with ears is 1 cm larger than the inner diameter, the inner diameter of the hole 521 of the small-sized demoulding steel ring with ears is the same as the inner diameter of the combined sample preparation tube, and the height of the small-sized demoulding steel ring with ears is equal to the thickness of the partition middle plate.

[0117] The specimen limiting steel rings include a medium-sized ear limiting steel ring 53 (corresponding to the laboratory standard specimen size of 61.8 mm) and a small ear limiting steel ring 54 (corresponding to the laboratory standard specimen size of 39.1 mm). The outer diameter of the ear 532 of the medium-sized ear limiting steel ring is 1 cm larger than the inner diameter, and the inner diameter of the hole 531 of the medium-sized ear limiting steel ring is the same as the inner diameter of the combined sample preparation tube. The height of the medium-sized ear limiting steel ring 53 is less than the thickness of the sliding steel plate 25; the outer diameter of the ear 542 of the small-sized ear limiting steel ring is 1 cm larger than the inner diameter, and the inner diameter of the hole 541 of the small-sized ear limiting steel ring is the same as the inner diameter of the corresponding combined sample preparation tube 32. The height of the small ear limiting steel ring 54 is less than the thickness of the sliding steel plate.

[0118] A method for automated stratified sampling of disturbed soil, using the above-mentioned automated stratified sampling device for disturbed soil based on a power-off limiter, comprises the following steps:

[0119] Prepare disturbed soil;

[0120] Assemble the equipment and movably mount the combined sample preparation cylinder 32 on the load-bearing frame module;

[0121] Fill the first layer of disturbed soil in the combined sample preparation cylinder 32, and use the compaction sample preparation module to make the pressure head 31 compact the disturbed soil, then remove the combined sample preparation cylinder 32 to fill the second layer of disturbed soil, and then compact it, and repeat this step until all soil layers are compacted;

[0122] Demolding, the pressure head 31 pushes out the soil sample in the combined sample preparation tube 32 and moves it to the tray 41, and the plurality of springs 42 are compressed until the sample is completely taken out, and then the sample is tightly covered with a plastic film to complete demolding.

[0123] As an optional implementation, the relationship between the number of springs 42 and the weight of the prepared sample is as follows:

[0124]

[0125] Where: N is the number of springs, a positive integer;

[0126] n—number of compaction layers;

[0127] h—the height of each layer when the sample is compacted;

[0128] m—mass of each layer of sample;

[0129] G—tray 41 weight, G ≥ 2nmg;

[0130] k—spring stiffness;

[0131] b—height of tray 41;

[0132] xmax—maximum compression of the spring, x max ≥nh-2.

[0133] An automatic layered sample preparation method for disturbed soil based on a power-off limiter is provided, taking the sample preparation process of a five-layer compacted clay sample as an example, and includes the following steps:

[0134] S1, prepare disturbed soil: break the air-dried clay, pass it through a 2 mm analysis sieve, and evenly spray distilled water on the sieved soil to form soil with a set moisture content; then put the soil with the set moisture content into a sealed bag and seal it for more than 24 hours to form disturbed soil with a predetermined moisture content.

[0135] S2, installing an automatic layered sample preparation device for disturbed soil based on a power-off limiter, comprising the following steps:

[0136] S201, assemble the demoulding module: calculate the required number of springs 42 according to the weight of the prepared sample, and reasonably distribute the positions of the springs 42, and install them on the basic bottom plate 23; then install the tray 41 on the springs 42, and install the telescopic self-locking support rod 43 to the bottom of the tray 41, and install the corresponding self-locking buckle 44 on the basic bottom plate 23 to complete the assembly of the variable stiffness spring tray; according to the size of the prepared sample, connect the partition middle plate 22 and the basic bottom plate 23 through the threaded support rod 24.

[0137] The relationship between the number of springs 42 and the weight of the sample is as follows:

[0138]

[0139] Where: N is the number of springs, a positive integer;

[0140] n—number of compaction layers;

[0141] h—the height of each layer when the sample is compacted;

[0142] m—mass of each layer of sample;

[0143] G—tray 41 weight, G ≥ 2nmg;

[0144] k—spring stiffness;

[0145] b—height of tray 41;

[0146] xmax—maximum compression of the spring, x max ≥nh-2.

[0147] The range of the number N of springs 42 can be calculated from the above two equations. max ≥N≥N min It can be seen that the number of springs 42 is related to the stiffness of the springs 42 and the maximum compression of the springs 42 , as well as the height of the tray 41 and the weight of the tray 41 .

[0148] To ensure the quality of the sample during demoulding, the multifunctional servo motor 34 maintains a constant speed of 1 cm / min to push out the sample. For the three standard samples commonly used in laboratories (with heights of 80 mm, 125 mm and 200 mm respectively), after demoulding, the distance between the sample and the bottom of the partition middle plate 22 is 2 cm, which is convenient for removing the sample.

[0149] Afterwards, the assembled contact-type power-off limiting device may be installed on the partition middle plate 22 first, that is, step S203 is implemented first, which is also within the protection scope of the present invention.

[0150] S202, assemble the compaction sample preparation module: open the horizontal telescopic slide rail 26 on the partition middle plate 22, the horizontal telescopic slide rail 26 is provided with a buckle, and open the light telescopic support rod 27, connect the light telescopic support rod 27 with the horizontal telescopic slide rail 26 and stably support it on the ground; install the sliding steel plate 25 with the limiting ring groove 251 on the horizontal telescopic slide rail 26; assume that when it is pulled out to the left, the sliding steel plate 25 with the limiting ring groove 251 is the sample preparation platform, and when it is pushed to the right, the sliding steel plate 25 with the limiting ring groove 251 is the compaction sample preparation platform, and at this time, the limiting ring groove 251 on the sliding steel plate 25 is coaxial with the pressure head 31 on the multifunctional servo motor 34; then install the reaction force top plate 21; install the multifunctional servo motor 34 on the reaction force top plate 21, select the pressure head 31 according to the sample size and connect the pressure head 31 with the compression rod 33 of the multifunctional servo motor 34;

[0151] S203, assemble the contact-type power-off limit device: install the metal limit contact 14 on the groove of the compression rod 33, insert five identical rotation limit sleeves 12 into the telescopic limit pillar 11, and install the telescopic limit pillar 11 in the limit pillar threaded groove 221 on the partition middle plate 22; install five identical power-off limiters 13 on the five identical rotation limit sleeves 12 respectively.

[0152] S204, adjust the position of the rotation limit sleeve 12: push the sliding steel plate 25 with the limit ring groove 251 to the right; take a sleeve steel ring and place it in the limit ring groove 251 of the sliding steel plate, then adjust the orientation of the first rotation limit sleeve 12 to be the same as the metal limit contact 14, control the multifunctional servo motor 34 to descend, so that the bottom surface of the pressure head 31 is just flush with the top surface of the sleeve steel ring, and the metal limit contact 14 on the compression rod 33 just contacts the power-off limiter 13 on the rotation limit sleeve, that is, the multifunctional servo motor 34 will stop compacting at this time, and then adjust the remaining rotation limit sleeves 12 so that the distance between the rotation limit sleeves 12 is equal and equal to the height of the sleeve steel ring.

[0153] In this embodiment, the combined sample preparation tube 32 has 5 sleeve steel rings. At this time, each disturbed soil sample after preparation has five layers.

[0154] S3, compacting and preparing a disturbed soil sample, comprising the following steps:

[0155] S301, loading the first layer of disturbed soil: pull the sliding steel plate 25 with the limiting ring groove 251 to the left, engage the two sleeve steel rings with each other, and place them in the limiting ring groove 251; evenly apply a layer of vaseline on the inner walls of the two sleeve steel rings, weigh 1 portion of the disturbed soil prepared in step 1, and pour it into the two engaged sleeve steel rings.

[0156] S302, first layer compaction: adjust the buckle position on the horizontal telescopic slide rail 26, push the sliding steel plate 25 to the rightmost end of the horizontal telescopic slide rail 26, make the pressure head 31 installed on the multifunctional servo motor 34 coaxial with the inner diameter of the sleeve steel ring on the sliding steel plate 25, fix the sliding steel plate 25, and according to step S205, adjust the power-off limiter 13 on the first rotation limit sleeve 12 to the same position as the metal limit contact piece 14, and the power-off limiter 13 on the remaining rotation limit sleeves 12 to the same position as the metal limit contact piece 14. The position of the device 13 avoids the position of the metal limit contact 14. Then, by adjusting the multifunctional servo motor 34, the compaction process is controlled according to the stress or strain, so that the pressure head 31 assembled in step S204 is slowly lowered under the drive of the multifunctional servo motor 34. When the metal limit contact 14 on the compression rod 33 contacts the first power-off limiter 13, that is, the bottom surface of the pressure head 31 reaches the top surface of the first sleeve steel ring, the multifunctional servo motor 34 is automatically powered off to complete the compaction operation of the first layer.

[0157] S303, loading the second layer of disturbed soil: open the buckle on the horizontal telescopic slide rail 26, slide the sliding steel plate 25 with the limiting ring groove 251 to the left, first roughen the upper surface of the first layer of compacted soil sample, and then engage the third sleeve steel ring with the second sleeve steel ring; evenly apply vaseline on the inner wall of the third sleeve steel ring, weigh 1 portion of the disturbed soil prepared in step 1, and pour it into the combined sample preparation barrel composed of three sleeve steel rings.

[0158] S304, second layer compaction: adjust the buckle position on the horizontal telescopic slide rail 26, push the sliding steel plate 25 to the rightmost end of the horizontal telescopic slide rail 26, make the pressure head 31 installed on the multifunctional servo motor 34 and the inner diameter of the sleeve steel ring on the sliding steel plate 25 just coaxial, fix the sliding steel plate 25, and adjust the power-off limiter 13 on the second rotation limit sleeve 12 to the same position as the metal limit contact piece 14 according to step S205, and the power-off limiter 13 on the remaining rotation limit sleeves 12 is adjusted to the same position as the metal limit contact piece 14. The position of the positioner 13 avoids the position of the metal limit contact 14. Then, by adjusting the multifunctional servo motor 34, the compaction process is controlled according to stress or strain, so that the pressure head 31 assembled in step S204 is slowly lowered under the drive of the multifunctional servo motor 34. When the metal limit contact 14 on the compression rod 33 contacts the second power-off limiter 13, that is, the bottom surface of the pressure head 31 reaches the top surface of the second sleeve steel ring, the multifunctional servo motor 34 is automatically powered off to complete the compaction operation of the second layer.

[0159] S4, repeat step S3 until the preparation of 5 layers of disturbed soil samples is completed.

[0160] S5, demoulding, the process includes: after the fifth layer of compaction is completed in step S4, the multifunctional servo motor 34 is controlled to make the pressure head 31 rise to a height that does not affect the removal of the sample, the sliding steel plate 25 with the limiting ring groove 251 is pulled out to the left, and the matching demoulding steel ring with ears is installed on the demoulding hole 223 on the partition middle plate 22, and then the compacted sample is placed on the demoulding steel ring with ears. According to step S201, the variable stiffness spring tray has been set according to the weight of the sample, and the mode of the multifunctional servo motor 34 is adjusted to make the pressure head 31 move slowly downward at a constant speed until the compacted sample is completely removed from the combined sample preparation barrel. At this time, the telescopic self-locking support rod 43 located on the tray 41 will automatically lock with the self-locking buckle 44 located on the base bottom plate 23, and finally the sample is taken out to complete the demoulding. Next, the disturbed soil sample that has been pushed out of the mold is tightly covered with a layer of plastic film to ensure that it is completely sealed to prevent the external environment from affecting it.

[0161] The present invention is used to produce three kinds of standard specimens commonly used in laboratories (respectively 39.1mm*80mm, 61.8mm*125mm and 101mm*200mm), the specimen limiting ring groove on the sliding steel plate corresponds to the standard specimen with a diameter of 101mm, the medium-sized limiting steel ring with ears corresponds to the standard specimen with a diameter of 61.8mm, and the small-sized limiting steel ring with ears corresponds to the standard specimen with a diameter of 39.1mm; the demoulding hole on the partition middle plate corresponds to the standard specimen with a diameter of 101mm, the medium-sized demoulding steel ring with ears corresponds to the standard specimen with a diameter of 61.8mm, and the small-sized demoulding steel ring with ears corresponds to the standard specimen with a diameter of 39.1mm.

[0162] Compared with the traditional technology, the present invention has the following beneficial effects:

[0163] 1. The sample preparation device provided by the present invention integrates the two steps of sample preparation and demoulding into one device, which simplifies the multi-step operation process of traditional disturbed soil sample preparation, making the entire soil sample preparation process more coherent and efficient; the integrated design makes the device more compact, saves laboratory space, reduces dependence on multiple independent devices, and reduces purchase and maintenance costs;

[0164] 2. In the present invention, the size of the pressure head can be replaced according to the size of the sample. The combined sample preparation cylinder has three sets of different inner diameters, and there are two sample limiting steel rings and two sample demoulding steel rings. The inner diameters of the two rings are the same as the inner diameters of the matching combined sample preparation cylinder. The design of this set of equipment allows us to prepare samples of different sizes according to different experimental requirements, and it has high flexibility and applicability.

[0165] 3. The compaction device of the present invention is a multifunctional servo motor, which can realize precise control of stress and strain, and thus precisely control the compaction process; the moment the metal limit contact piece contacts the power-off limiter, the multifunctional servo motor is immediately powered off; this design can improve the accuracy of the compaction process, prevent overpressure or underpressure, and the degree of compaction is controlled by the power-off limiter without manual measurement, which also makes the operation simpler, more efficient, intelligent and automated.

[0166] 4. The number of springs described in the present invention can be adjusted according to the weight of the prepared sample. Before the test, the number of springs can be calculated according to the provided calculation formula, so that when the sample is compacted, the self-locking telescopic rod is locked with the self-locking hook. The design of the locking mechanism simplifies the sample removal process, allowing the experimenter to easily remove the compacted sample from the device, thereby improving work efficiency.

[0167] 5. The height position of the separating middle plate and the reaction top plate in the sample preparation device provided by the present invention can be adjusted according to the height of the prepared sample through the threaded support rod and the hexagonal bolt; the telescopic limit support can be extended and retracted, and the rotary limit bearing has the function of vertical movement and rotation; the telescopic self-locking support rod on the tray can be extended and retracted; the lightweight telescopic support rod can adjust the telescopic height according to the position of the separating middle plate according to the sample size; the flexible height adjustment mechanism enables the device to adapt to the preparation needs of soil samples of different heights and multiple layers, and has strong adaptability.

[0168] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0169] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An automatic layered sample preparation device for disturbed soil based on a power-off limiter, characterized in that: include: Load-bearing frame module; A combined sample preparation cylinder (32) movably arranged on the carrying frame module; A compaction sample preparation module is installed on the upper part of the load-bearing frame module, and the compaction sample preparation module is provided with a vertically movable pressure head (31), and the pressure head (31) is used to compact the soil sample filled in the combined sample preparation cylinder (32); A demoulding module is installed at the bottom of the load-bearing frame module, and the demoulding module comprises a tray (41). The tray (41) is elastically arranged in the load-bearing frame module through a plurality of springs (42). After the combined sample preparation cylinder (32) with the compacted soil sample is moved above the tray (41), the pressing head (31) pushes the soil sample in the combined sample preparation cylinder (32) onto the tray (41) to remove the soil sample; A limit module is installed on the bearing frame module and is used to control the displacement distance of the pressure head (31).

2. The automatic layered sample preparation device for disturbed soil based on a power-off limiter according to claim 1 is characterized in that: The load-bearing frame module comprises: A base bottom plate (23), a partition middle plate (22) and a reaction top plate (21) that are fixedly connected, wherein a gap is provided between the base bottom plate (23) and the partition middle plate (22), and a gap is provided between the partition middle plate (22) and the reaction top plate (21); A demoulding hole (223) is provided in the middle of the partition middle plate (22); A translation module, used for horizontal movement of the combined sample preparation cylinder (32), wherein a fixed end of the translation module is fixedly connected to the partition middle plate (22); The limiting module is installed on the partition middle plate (22).

3. The automatic layered sample preparation device for disturbed soil based on a power-off limiter according to claim 2 is characterized in that: The translation module comprises two horizontal telescopic slide rails (26), the fixed ends of the horizontal telescopic slide rails (26) are fixedly connected to the top surface of the partition middle plate (22), the two horizontal telescopic slide rails (26) are symmetrically arranged on both sides of the demoulding hole (223), the movable ends of the horizontal telescopic slide rails (26) are fixedly connected to light telescopic support rods (27), and the light telescopic support rods (27) are vertical to the horizontal telescopic slide rails (26) in space; The two horizontal telescopic slide rails (26) are slidably connected to the bottom of the same sliding steel plate (25), a limiting ring groove (251) is provided in the middle of the sliding steel plate (25), a limiting steel ring is limitedly matched in the limiting ring groove (251), and a slide rail limiting groove (252) for slidably matching with the horizontal telescopic slide rail (26) is provided at the bottom of the sliding steel plate (25).

4. The automatic layered sample preparation device for disturbed soil based on a power-off limiter according to claim 2 is characterized in that: The limit module comprises: A telescopic limiting pillar (11), the bottom end of the telescopic limiting pillar (11) is fixedly connected to the partition middle plate (22), a plurality of rotation limiting sleeves (12) are movably arranged in the middle of the telescopic limiting pillar (11), the inner side of the rotation limiting sleeve (12) vertically slides with the telescopic limiting pillar (11) through a plurality of surrounding balls (113), the side wall of the rotation limiting sleeve (12) is threadedly connected with a fixing bolt (121), the fixing bolt (121) and the side wall of the telescopic limiting pillar (11) are frictionally matched to fix the rotation limiting sleeve (12) and the telescopic limiting pillar (11); the top of the telescopic limiting pillar (11) contacts the bottom of the reaction top plate (21); An annular slide rail (122) is provided on the outer side of the rotation limiting shaft sleeve (12), and a power-off limiter (13) is slidably connected inside the annular slide rail (122). The power-off limiter (13) can contact a metal limiting contact piece (14), and the metal limiting contact piece (14) is fixedly connected to one side of the pressure head (31).

5. The automatic layered sample preparation device for disturbed soil based on a power-off limiter according to claim 4 is characterized in that: The compaction sample preparation module comprises: A multifunctional servo motor (34) has a fixed end fixedly connected to the reaction force top plate (21); the telescopic end of the multifunctional servo motor (34) passes through the reaction force top plate (21) and is axially connected to the top end of a compression rod (33); the bottom end of the compression rod (33) is fixedly connected to the pressure head (31); and one side of the middle portion of the compression rod (33) is fixedly connected to one end of the metal limit contact piece (14).

6. The device for automatically preparing samples of disturbed soil by stratification based on a power-off limiter according to claim 2, characterized in that: The tray (41) of the demoulding module is located below the partition middle plate (22), the tray (41) is elastically connected to the base bottom plate (23) via a plurality of springs (42), and the tray (41) is limitedly matched with the base bottom plate (23) after being pressed down; The demoulding module also includes a demoulding steel ring, which is installed in the demoulding hole (223) and is limitedly matched with the demoulding hole (223).

7. The automatic layered sample preparation device for disturbed soil based on a power-off limiter according to claim 6 is characterized by: The base bottom plate (23) is provided with a plurality of spring thread grooves (231) arranged in a matrix, the bottom of the spring (42) is axially connected with a spring thread rod (421), and the spring thread rod (421) is threadedly connected with the spring thread groove (231).

8. The device for automatically preparing samples of disturbed soil by stratification based on a power-off limiter according to claim 6, characterized in that: The front and rear sides of the bottom of the tray (41) are respectively fixedly connected with telescopic self-locking support rods (43), and the telescopic self-locking support rods (43) are limitedly matched with self-locking buckles (44), and the self-locking buckles (44) are fixedly connected to the base bottom plate (23).

9. An automated layered sampling method for disturbed soil, using the automated layered sampling device for disturbed soil based on a power-off limiter according to any one of claims 1 to 8, characterized in that: The steps include: Prepare disturbed soil; Assembling equipment to movably mount the combined sample preparation cylinder (32) on the load-bearing frame module; Filling the first layer of disturbed soil in the combined sample preparation cylinder (32), and using the compaction sample preparation module to make the pressure head (31) compact the disturbed soil, then removing the combined sample preparation cylinder (32) to fill the second layer of disturbed soil, and then compacting it, repeating this step until all soil layers are compacted; Demolding, the pressing head (31) pushes out the soil sample in the combined sample preparation cylinder (32) and moves it onto the tray (41), and the plurality of springs (42) are compressed until the sample is completely taken out, and then the sample is tightly covered with a plastic film to complete demoulding.

10. The method for automated stratified sampling of disturbed soil according to claim 9, characterized in that: The relationship between the number of the springs (42) and the weight of the prepared sample is as follows: Where: N is the number of springs, a positive integer; n—number of compaction layers; h—the height of each layer when the sample is compacted; m—mass of each layer of sample; G—weight of the tray (41), G≥2nmg; k—spring stiffness; b—height of the tray (41); xmax—maximum compression of the spring, x max ≥nh-2.

Images