CN111982675B - Test method for integral soil uniaxial tension device - Google Patents
Test method for integral soil uniaxial tension device Download PDFInfo
- Publication number
- CN111982675B CN111982675B CN202010716525.0A CN202010716525A CN111982675B CN 111982675 B CN111982675 B CN 111982675B CN 202010716525 A CN202010716525 A CN 202010716525A CN 111982675 B CN111982675 B CN 111982675B
- Authority
- CN
- China
- Prior art keywords
- stretching
- sliding
- sample
- die
- soil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/36—Embedding or analogous mounting of samples
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/04—Chucks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/06—Special adaptations of indicating or recording means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/36—Embedding or analogous mounting of samples
- G01N2001/366—Moulds; Demoulding
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/025—Geometry of the test
- G01N2203/0252—Monoaxial, i.e. the forces being applied along a single axis of the specimen
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0298—Manufacturing or preparing specimens
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a test method of an integral soil uniaxial tension device, which comprises the following steps of 1, assembling a visual integral mold; firstly assembling a die bottom plate, and then assembling a detachable L-shaped plate; step 2, preparing a sample, namely filling a soil body sample by adopting a layered tamping method; step 3, installing a shaft drawing device: connecting the die drawing half with an oil pressure chest expander; step 4, disassembling the L-shaped plate; step 5, stretching; and 6, breaking the sample: the oil pressure chest expander is further stretched, and the stretching deformation part of the soil body sample is broken after reaching the maximum bearing capacity; meanwhile, the sliding strip positioned right below the fracture part is driven by the fracture sample above to be separated from each other, so that the fracture position of the sample is recorded; and 7, drawing a tensile stress-time curve and a tensile displacement-time curve. The invention directly modifies the mould used for sample preparation into the movable clamp, realizes the integration of the mould and the movable clamp, omits demoulding and can observe the specific fracture position.
Description
Technical Field
The invention relates to a soil test device, in particular to a test method of an integral soil uniaxial tension device.
Background
The soil is a weathered product of rock and has certain shear strength, compressive strength and tensile strength on the aspect of mechanical properties. However, in engineering construction, the tensile strength of soil is basically not utilized by people, so that the tensile strength of soil is mostly ignored when people study the strength of soil. However, the soil body is sometimes subjected to tensile stress in engineering, which is a problem that cannot be avoided, and the tensile stress action often occurs around tall buildings. Therefore, in recent years, the problem of tensile strength of soil bodies is more and more prominent, and people have attracted wide interest.
The test method for measuring the tensile strength of the soil body mainly comprises the following steps: uniaxial tensile test, triaxial tensile test, soil beam bending test, hollow cylinder test, radial fracturing test, Brazilian splitting test and the like. The uniaxial tensile test and the triaxial tensile test are used for measuring the tensile strength by directly applying axial tension to a sample, and belong to a direct tensile test method; a bending test, a radial fracturing test, an axial fracturing test and a hollow cylinder test of a soil beam are carried out by applying pressure or torque to a sample and calculating the tensile strength of a soil body from the pressure or the torque when the soil sample is damaged according to a certain hypothesis, and belong to an indirect tensile test method.
The stress control type horizontal uniaxial tension meter developed according to the modesty and the like has the advantages that the operation of the test method is convenient, the test result is clear, but the rotating speed is not fixed because the hand wheel is manually controlled, and the condition that whether the eccentric tension occurs in the re-tension process of the sample cannot be solved.
A horizontal uniaxial tension meter developed by Tamrakar has a sample with a 8-shaped section. The new test instrument eliminates the effect of the clamps and the adhesive on the test specimen, but due to the particular mould shape, the preparation of the test specimen is greatly limited and the accuracy of the tensile stress values applied during the test and the local stress values at failure need to be questioned.
The instrument designed by Zhang Hui and Zhujun and the like can adopt a clamp method to carry out soil uniaxial tensile test. The instrument can continuously apply loads which are hooked and adopts the electronic data acquisition, the result of the test instrument is accurate, and the operation is simple. However, the sample is fixed by the clamp, so that slight relative sliding is easy to occur, and the study on the deformation of the soil body is not facilitated.
Traditional unipolar stretching device is all at mould back surface paint the release agent, then begins to make the appearance, accomplishes the system appearance after, takes out the sample from the mould, puts into movable anchor clamps again or with adhesive bonding movable anchor clamps and sample both ends, then tests, and this not only can cause the damage to the sample, and still very loaded down with trivial details, the fixed sample of movable anchor clamps can produce the relative slip phenomenon of microgroove to influence the test result.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art and provides a test method of an integral soil uniaxial tension device, which integrates a sample preparation mold and a movable clamp, reduces the sample demolding and clamping processes, is simple and convenient to detect and can observe the sample fracture process and the accurate fracture position.
In order to solve the technical problems, the invention adopts the technical scheme that:
a test method of an integral soil uniaxial tension device comprises the following steps.
Step 1, assembling a visual integrated mold, which specifically comprises the following steps.
Step 2, sample preparation, which specifically comprises the following steps:
step 21, preparing a sample soil body: calculating the mass of water and soil according to the required water content, adding water while stirring the soil, mixing uniformly, and fully standing; then, the sample soil after standing is divided into n parts with equal weight.
And step 22, sequentially filling n sample soil bodies into the dumbbell-shaped sample cavities, and filling and compacting the soil body samples by adopting a layered compacting method.
Step 4, disassembling the L-shaped plate: the fixed bent iron is firstly disassembled, and the connection between the L-shaped plate and the fixed half part of the mould and the stretching half part of the mould is released. And then disassembling the L-shaped plates positioned at two sides of the plurality of sliding strips. Therefore, soil body samples positioned at the tops of the plurality of sliding strips are exposed outside, and observation is facilitated.
Step 5, stretching: and starting the oil pressure chest expander, gradually stretching the half stretched mold, monitoring the tensile stress applied to the half stretched mold by the oil pressure chest expander in real time by the stress sensor, and transmitting the recorded tensile stress to the computer. And in the stretching process of the mold stretching half, the soil mass of the sample positioned in the mold fixing half and the mold stretching half forms two clamping ends due to the dumbbell-shaped shrinkage effect, and the soil mass sample positioned at the tops of the plurality of sliding strips becomes a stretching deformation part. With the continuous stretching of the oil pressure chest expander, the stretching deformation part of the soil body sample in the step 5 deforms along the stretching direction. Meanwhile, the sliding strip at the bottom of the tensile deformation part slides along the sliding ball along with the soil sample.
And 6, breaking the sample: the oil pressure chest expander is further stretched, and the stretching deformation part of the soil body sample is broken after reaching the maximum bearing capacity; meanwhile, the sliding strips positioned right below the fracture part are separated from each other under the driving of the fracture of the sample, so that the fracture position of the sample is recorded.
In step 11, when assembling the bottom plate of the mold, the number of the sliding strips is selected according to the length of the soil mass sample to be simulated. The longer the length of the soil body sample to be simulated is, the more the number of the sliding strips is, so that the soil body samples with different lengths can be simulated. In step 12, the width of the L-shaped plate is selected based on the selected total stretch-wise width of all the slider bars.
The width of each slider in the direction of stretching was 1 cm.
In step 12, the L-shaped plates which are spliced at two sides of the plurality of sliding strips and are positioned between the fixed half part of the mould and the stretching half part of the mould are formed by splicing two or more standard L-shaped plates with standard widths.
In step 11, the bottom of the fixed half of the mold, the bottom of each sliding strip and the bottom of the stretched half of the mold are provided with sliding grooves matched with the sliding balls. In the stretching process of step 5, the sliding groove provides a guiding function along the sliding ball on one hand, and on the other hand, the sliding groove and the sliding ball directly form frictionless rolling through the finish treatment of the sliding groove.
The bottom of each sliding strip is also provided with a small sliding ball, and frictionless sliding is formed between the small rolling ball and the bottom plate.
Step 21, numbering the n standing sample soil bodies as 1 st part, 2 nd part, … … th part and nth part respectively; in step 22, assuming that the height of the required sample is H; firstly, filling and compacting the soil mass 1 at the bottommost part of the mold, wherein the compacting height H1 of the soil mass 1 is greater than (1/n) H, the compacting height of the soil mass 2 is H2, H1 > H2 > (1/n) H, the compacting height of the soil mass third is H3, H1 > H2 > H3 > (1/n) H, and so on, and finally ensuring that the compacting degrees of the soil masses are the same; after each soil body is compacted, the surface of each soil body is scraped by a scraper, so that the soil body can be better combined with the lower surface of the upper soil body.
In step 3, a displacement sensor connected with a computer is also arranged between the die drawing half and the oil pressure chest expander; in the step 5, the displacement sensor monitors the axial stretching displacement of the stretching half of the die in real time and transmits the recorded axial stretching displacement to a computer; in step 7, the computer draws an axial tension displacement-time curve according to the received axial tension displacement.
The invention has the following beneficial effects:
(1) the mould that will system appearance used is directly reformed transform into movable anchor clamps, realizes the integration of mould and movable anchor clamps, saves a series of operations such as drawing of patterns, avoids the sample to damage, avoids movable anchor clamps fixed sample moreover to produce the relative slip phenomenon of microgroove, reduces to exert an influence to the experiment
(2) A plurality of sliding strips are arranged in parallel at the lower end of the sample fracture part, so that the supporting effect can be achieved, and the effect of limiting movement of the whole die can be achieved through the sliding grooves in the sliding strips. When the sliding strip separates each other along sliding ball length direction under the drive of sample, not only can not cause the friction to the sample, cause the influence to the experiment, can also know the position that the crack specifically takes place.
(3) And utilize the sliding ball of multirow different positions, change the contact surface roll that traditional mutual slip becomes the sliding ball, reduce the friction of visual integral type mould tensile in-process and bottom plate, reach more ideal experimental state, the experimental data measurement's of being convenient for accuracy and reliability.
Drawings
Fig. 1 shows a structural schematic diagram of the fracture visualization integrated soil uniaxial stretching device.
FIG. 2 shows an exploded view of a visualization unibody mold of the present invention.
Fig. 3 shows a number of sliders according to the invention and a schematic drawing of the sliders being pulled apart.
Fig. 4 shows a front view of the slide bar of fig. 3.
Fig. 5 shows a schematic view of a base plate according to the invention.
Fig. 6 shows a schematic view of a cover plate according to the invention.
Figure 7 shows a schematic representation of a soil sample of the invention.
Fig. 8 shows a schematic view of the use of the entire device of the present invention.
In fig. 8a, a drawing of the mold halves, slide bars, and mold halves in combination is shown resting on a base plate.
In fig. 8b, a schematic view of a state where an L-shaped plate is added on the basis of a is shown.
Fig. 8c is a schematic view showing a state where a fixed bending iron and a screw are added to b.
Fig. 8d shows a schematic view of the state of the impact compaction sample based on c.
In fig. 8e, a schematic view of the state of mounting the uniaxial tension device on the basis of d is shown.
Fig. 8f is a schematic view showing a state where the fixed bending iron and the screw are detached from each other on the basis of e.
In fig. 8g, a schematic view of the state where the L-shaped plate is detached on the basis of f is shown.
In fig. 8h, a schematic view of the state of fracture after stretching is shown.
Among them are:
1. an oil pressure chest expander; 2. a collector; 3. a data line; 4. a displacement sensor; 5. a stress sensor;
6. drawing the die by half; 6-1, stretching holes;
7. fixing a mold half; 7-1, a sliding groove; 7-2, fixing holes;
8. an L-shaped plate; 9. fixing the bent iron; 10. a screw;
11. a slide bar; 11-1, a sliding groove; 11-2, small sliding balls;
12. a fixing plate; 13. a base plate; 14. a sliding ball; 15. and (7) a cover plate.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific preferred embodiments.
In the description of the present invention, it is to be understood that the terms "left side", "right side", "upper part", "lower part", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and that "first", "second", etc., do not represent an important degree of the component parts, and thus are not to be construed as limiting the present invention. The specific dimensions used in the present example are only for illustrating the technical solution and do not limit the scope of protection of the present invention.
As shown in fig. 1, a visual integral soil body uniaxial tension device of fracture comprises a bottom plate 13, a visual integral mold, a fixing plate 12, an oil pressure chest expander 1, a collector 2, a displacement sensor 4 and a stress sensor 5.
The bottom plate is fixed in position, such as on the ground or a workbench. As shown in fig. 5, the middle of the bottom plate is provided with two rows of sliding balls 14 each along the length direction.
The fixed plate is fixedly arranged on the bottom plate at one end of the sliding ball, and the oil pressure chest expander is fixedly arranged on the bottom plate at the other end of the sliding ball. The stress sensor is arranged on a stretching rod connected with the oil pressure chest expander on the stretching half of the die.
The displacement sensor is used for detecting the stretching displacement of the stretching half part of the die, and is preferably arranged on an oil pressure chest expander.
The collector is preferably connected with a computer, a stress sensor and a displacement sensor through data lines 3.
Visual integral type mould sliding connection is on two rows of sliding balls.
As shown in fig. 2, the visual integrated mold comprises a mold fixing half 7, a mold stretching half 6, an L-shaped plate 8, a fixing bent iron 9, a sliding bar 11 and a cover plate 15.
The fixed half of mould and the tensile half relative slip setting of mould are on two rows of sliding balls, and one side in opposite directions all is provided with the opening, and the shape is similar to trapezoidal prism, has the shrink section at the opening part.
The bottom of the fixed half of the mould is preferably provided with a sliding groove 7-1 matched with the two rows of sliding balls, and the bottom of the drawing half of the mould is preferably provided with a sliding groove matched with the two rows of sliding balls
The die holding half is preferably connected to the holding plate via holding bores 7-2, and the die drawing half is preferably connected to the oil-pressure tensioner via drawing bores 6-1.
And the sliding strips are arranged on the sliding ball between the fixed half part of the mould and the stretching half part of the mould in a sliding mode in parallel, and each sliding strip is arranged along the width direction of the bottom plate.
As shown in fig. 3 and 4, the bottom of each slide bar is preferably provided with a slide groove 11-1 for fitting two rows of slide balls. The bottom of each sliding strip positioned between or outside the two sliding grooves is provided with at least one row of small sliding balls 11-2, preferably two rows of small sliding balls, which are used for ensuring the vertical clearance between the sliding strips and the bottom plate and the smoothness of sliding on the bottom plate.
The sliding ball is preferably a hard metal ball, the surface is smooth, one part of the sliding ball is embedded in the bottom plate, one part of the sliding ball is exposed out of the bottom plate and can rotate in the bottom plate, the part of the sliding ball, which is exposed out of the floor, just can be matched with the sliding groove, and the half part of the die, which is stretched, the plurality of rolling strips and the half part of the die, which is fixed, can roll on the sliding ball and have a certain gap (vertical gap) with the bottom plate.
The vertical clearance is arranged, on one hand, the vertical clearance can not contact the bottom plate, and the friction between the bottom of the fixed half of the mold, the stretching half of the mold and the bottom of each sliding strip and the bottom plate is prevented; and on the other hand, to provide a receiving space for the small sliding ball 11-2.
The L-shaped plate is spliced between the die fixing half part and the die stretching half part on two sides of the plurality of sliding strips, and is detachably connected with the die fixing half part and the die stretching half part through the fixing bent iron and the screws 10.
A dumbbell-shaped sample cavity is formed among the die fixing half, the die stretching half, the L-shaped plate and the sliding strip and is used for preparing a soil mass sample shown in figure 7.
The cover plate 15 shown in fig. 6 has a size just slightly smaller than the inner edge of the mold, and preferably covers the top of the sample chamber, and is used for compacting the soil mass through the cover plate 15.
A test method of an integral soil uniaxial tension device comprises the following steps.
Step 1, assembling a visual integrated mold, which specifically comprises the following steps.
The number of the sliding strips is preferably selected according to the length of the soil body sample to be simulated. The longer the length of the soil body sample to be simulated is, the more the number of the sliding strips is, so that the soil body samples with different lengths can be simulated. The stretch width of each slider is preferably 1 cm. The bottom of the fixed half of the mould, the bottom of each sliding strip and the bottom of the stretched half of the mould are provided with sliding grooves matched with the sliding balls. The bottom of each sliding strip is also preferably provided with a small sliding ball, and friction-free sliding is formed between the small rolling ball and the bottom plate.
Further, the width of the L-shaped plate is preferably selected according to the total stretching width of all the slide bars. The L-shaped plates are preferably formed by splicing two or more standard L-shaped plates with standard widths, so that the L-shaped plates can adapt to different total stretching widths.
Step 2, sample preparation, which specifically comprises the following steps:
step 21, preparing a sample soil body: the mass of water and soil was calculated from the required water content, water was added while stirring the soil, and after mixing, the mixture was allowed to stand sufficiently.
Next, the sample soil after standing was divided into n parts by weight equal to each other, and numbered 1 st part, 2 nd part, … … th part, and n th part, respectively.
Sequentially filling n sample soil bodies into the dumbbell-shaped sample cavities, filling and compacting the soil body samples by adopting a layered compacting method, and assuming that the height of the required sample is H. Firstly, filling and compacting the 1 st soil body at the bottommost part of the mould, if the 1 st soil body is compacted to the height of 1/n, and filling and compacting the 2 nd soil body are carried out on the basis, the work of the compaction hammer from the upper part is acted on the 2 nd soil body when the 2 nd soil body is filled and compacted, and simultaneously, the 1 st soil body below the 2 nd soil body is further compacted, so that the compaction degree of the 1 st soil body is higher than that of the 2 nd soil body. Therefore, in practical operation, the compaction height H1 of the 1 st soil mass is required to be greater than (1/n) H, the compaction height of the 2 nd soil mass is H2, H1 > H2 > (1/n) H, the compaction height of the third soil mass is H3, H1 > H2 > H3 > (1/n) H, and so on, and finally the compaction degrees of each soil mass are the same, namely, although compaction is carried out in a layered mode, the compaction degree of each layer of an actual sample is the same, and the purpose of compaction in a layered mode is only to avoid the problem that the compaction degrees of the samples are different from top to bottom. .
After the compaction of the 1 st soil body is completed, the scraper is used for scraping the surface of the soil body, so that the upper soil body and the 2 nd soil body can be better combined, and the rest can be analogized, and the scraping treatment is also carried out after the compaction of the 2 nd soil body.
And (3) in layered compaction, preferably covering a cover plate on the surface of the sample to be compacted to compact. And after compaction, taking down the cover plate.
Step 4, disassembling the L-shaped plate: the fixed bent iron is firstly disassembled, and the connection between the L-shaped plate and the fixed half part of the mould and the stretching half part of the mould is released. And then disassembling the L-shaped plates positioned at two sides of the plurality of sliding strips. Therefore, soil body samples positioned at the tops of the plurality of sliding strips are exposed outside, and observation is facilitated.
Step 5, stretching: the oil pressure chest expander is started, the die is stretched half gradually, the stress sensor monitors the tensile stress applied to the die by the oil pressure chest expander in real time, the displacement sensor monitors the axial tensile displacement of the die by the die in real time, and the recorded tensile stress and the axial tensile displacement are transmitted to the computer.
And in the stretching process of the mold stretching half, the soil mass of the sample positioned in the mold fixing half and the mold stretching half forms two clamping ends due to the dumbbell-shaped shrinkage effect, and the soil mass sample positioned at the tops of the plurality of sliding strips becomes a stretching deformation part. With the continuous stretching of the oil pressure chest expander, the stretching deformation part of the soil body sample in the step 5 deforms along the stretching direction. Meanwhile, the sliding strip at the bottom of the tensile deformation part slides along the sliding ball along with the soil sample.
During the stretching process, the sliding groove provides a guiding function along the sliding ball on one hand, and on the other hand, the sliding groove and the sliding ball directly form frictionless rolling through the finish treatment of the sliding groove.
And 6, breaking the sample: and the oil pressure chest expander is further stretched, and the stretching deformation part of the soil body sample is broken after reaching the maximum bearing capacity. Meanwhile, the sliding strips positioned right below the fracture part are mutually driven by the fracture of the sample, so that the fracture position of the sample is recorded.
According to the invention, the integration of the die and the movable clamp can be realized, a series of operations such as demoulding and the like are omitted, the damage of the sample is avoided, the relative sliding phenomenon of fine lines generated when the movable clamp fixes the sample is avoided, and the influence on the experiment is reduced; a plurality of sliding strip is arranged in parallel at sample fracture department lower extreme, not only can play the supporting role, can also be through the sliding tray on the sliding strip to the spacing effect of removing of whole mould, separates each other along sliding ball length direction under the drive of sample as the sliding strip, not only can not cause the friction to the sample, causes the influence to the experiment, can also know the position that the crack specifically takes place.
Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the details of the embodiments, and various equivalent modifications can be made within the technical spirit of the present invention, and the scope of the present invention is also within the scope of the present invention.
Claims (8)
1. A test method of an integral soil uniaxial tension device is characterized by comprising the following steps:
the uniaxial drawing device comprises a bottom plate, a visual integrated die, a fixing plate and an oil-pressure chest expander;
the bottom plate is fixed in position, and the middle part of the bottom plate is provided with two rows of sliding balls along the length direction;
the fixed plate is fixedly arranged on the bottom plate at one end of the sliding ball, and the oil pressure chest expander is fixedly arranged on the bottom plate at the other end of the sliding ball;
the visual integrated die is connected to the two rows of sliding balls in a sliding manner;
the visual integrated die comprises a die fixing half, a die stretching half, an L-shaped plate, a fixing bent iron and a sliding strip;
the die fixing half and the die stretching half are arranged on the two rows of sliding balls in a relatively sliding manner, and openings are formed in opposite sides of the die fixing half and the die stretching half; the fixed half of the mould is connected with the fixed plate, and the stretching half of the mould is connected with the oil-pressure chest expander;
the sliding strips are arranged on the sliding ball between the die fixing half and the die stretching half in a sliding mode in parallel, and each sliding strip is arranged along the width direction of the bottom plate;
the L-shaped plate is spliced between the die fixing half and the die stretching half on two sides of the plurality of sliding strips and is detachably connected with the die fixing half and the die stretching half through the fixed bent iron;
a dumbbell-shaped sample cavity is formed among the die fixing half, the die stretching half, the L-shaped plate and the sliding strip;
the test method comprises the following steps:
step 1, assembling a visual integrated mold, comprising the following steps:
step 11, assembling a die bottom plate: sequentially connecting a fixed half of the mold, a plurality of sliding strips arranged in parallel and a stretched half of the mold to two rows of sliding balls of the bottom plate in a sliding manner; then, connecting the fixed half of the mould with a fixed plate;
step 12, assembling an L-shaped plate: firstly, splicing the L-shaped plate between a mould fixing half and a mould stretching half on two sides of a plurality of sliding strips to form a dumbbell-shaped sample cavity; then, using a fixed bent iron to respectively connect the L-shaped plate with the die fixing half and the die stretching half;
step 2, sample preparation, which specifically comprises the following steps:
step 21, preparing a sample soil body: calculating the mass of water and soil according to the required water content, adding water while stirring the soil, mixing uniformly, and fully standing; then, dividing the sample soil body after standing into n parts with equal weight;
step 22, sequentially filling n sample soil bodies into the dumbbell-shaped sample cavities, and filling and compacting the soil body samples by adopting a layered compacting method;
step 3, installing a shaft drawing device: the shaft pulling device comprises an oil pressure chest expander and a stress sensor; connecting the die drawing half with an oil pressure chest expander; a stress sensor connected with a computer is arranged between the die drawing half and the oil pressure chest expander;
step 4, disassembling the L-shaped plate: firstly, disassembling the fixed bent iron, and removing the connection between the L-shaped plate and the fixed half and the stretching half of the die; then, disassembling the L-shaped plates positioned at two sides of the plurality of sliding strips; therefore, soil body samples positioned at the tops of the plurality of sliding strips are exposed outside, and observation is facilitated;
step 5, stretching: starting the oil pressure chest expander, gradually stretching the mold stretching half, monitoring the tensile stress applied to the mold stretching half by the oil pressure chest expander in real time by a stress sensor, and transmitting the recorded tensile stress to a computer; in the stretching process of the mold stretching half, soil samples in the mold fixing half and the mold stretching half form two clamping ends due to the dumbbell-shaped shrinkage effect, and soil samples at the tops of the plurality of sliding strips become stretching deformation parts; with the continuous stretching of the oil pressure chest expander, the stretching deformation part of the soil body sample in the step 5 deforms along the stretching direction; meanwhile, the sliding strip positioned at the bottom of the tensile deformation part slides along the sliding ball along with the soil body sample above;
and 6, breaking the sample: the oil pressure chest expander is further stretched, and the stretching deformation part of the soil body sample is broken after reaching the maximum bearing capacity; meanwhile, the sliding strips positioned right below the fracture part are mutually separated under the driving of the fracture of the sample, so that the fracture position of the sample is recorded;
step 7, drawing a curve: and drawing a tensile stress-time curve by the computer according to the received tensile stress.
2. The testing method of the uniaxial integral soil mass stretching device according to claim 1, which is characterized in that: step 11, when assembling the bottom plate of the mold, selecting the number of the sliding strips according to the length of a soil body sample to be simulated; the longer the length of the soil mass sample to be simulated is, the more the number of the sliding strips is, so that the soil mass samples with different lengths can be simulated; in step 12, the width of the L-shaped plate is selected based on the selected total stretch-wise width of all the slider bars.
3. The testing method of the uniaxial integral soil mass stretching device according to claim 2, which is characterized in that: the width of each slider in the direction of stretching was 1 cm.
4. The testing method of the uniaxial integral soil mass stretching device according to claim 2, which is characterized in that: in step 12, the L-shaped plates which are spliced at two sides of the plurality of sliding strips and are positioned between the fixed half part of the mould and the stretching half part of the mould are formed by splicing two or more standard L-shaped plates with standard widths.
5. The testing method of the uniaxial integral soil mass stretching device according to claim 1, which is characterized in that: in step 11, sliding grooves matched with the sliding balls are formed in the bottom of the mold fixing half, the bottom of each sliding strip and the bottom of the mold stretching half; in the stretching process of step 5, the sliding groove provides a guiding function along the sliding ball on one hand, and on the other hand, the sliding groove and the sliding ball directly form frictionless rolling through the finish treatment of the sliding groove.
6. The testing method of the uniaxial integral soil mass stretching device according to claim 5, which is characterized in that: the bottom of each sliding strip is also provided with a small sliding ball, and frictionless sliding is formed between the small rolling ball and the bottom plate.
7. The testing method of the uniaxial integral soil mass stretching device according to claim 1, which is characterized in that: in step 21, numbering the n standing sample soil bodies as No. 1, No. 2, No. … … and No. n respectively; in step 22, assuming that the height of the required sample is H; firstly, filling and compacting the soil mass 1 at the bottommost part of the mold, wherein the compacting height H1 of the soil mass 1 is greater than (1/n) H, the compacting height of the soil mass 2 is H2, H1 > H2 > (1/n) H, the compacting height of the soil mass third is H3, H1 > H2 > H3 > (1/n) H, and so on, and finally ensuring that the compacting degrees of the soil masses are the same; after each soil body is compacted, the surface of each soil body is scraped by a scraper, so that the soil body can be better combined with the lower surface of the upper soil body.
8. The testing method of the uniaxial integral soil mass stretching device according to claim 1, which is characterized in that: in step 3, a displacement sensor connected with a computer is also arranged between the die drawing half and the oil pressure chest expander; in the step 5, the displacement sensor monitors the axial stretching displacement of the stretching half of the die in real time and transmits the recorded axial stretching displacement to a computer; in step 7, the computer draws an axial tension displacement-time curve according to the received axial tension displacement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010716525.0A CN111982675B (en) | 2020-07-23 | 2020-07-23 | Test method for integral soil uniaxial tension device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010716525.0A CN111982675B (en) | 2020-07-23 | 2020-07-23 | Test method for integral soil uniaxial tension device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111982675A CN111982675A (en) | 2020-11-24 |
| CN111982675B true CN111982675B (en) | 2021-07-13 |
Family
ID=73438826
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010716525.0A Active CN111982675B (en) | 2020-07-23 | 2020-07-23 | Test method for integral soil uniaxial tension device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111982675B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113405918B (en) * | 2021-06-09 | 2024-01-26 | 重庆交通大学 | Device for automatically determining soil body fracture toughness and application method thereof |
| CN113390715B (en) * | 2021-06-21 | 2022-03-18 | 水利部交通运输部国家能源局南京水利科学研究院 | Gravel-doped clay stretching device suitable for different gravel-doped particle sizes and testing method |
| CN113686687A (en) * | 2021-08-25 | 2021-11-23 | 山东东宏管业股份有限公司 | Device and method for testing tensile strength of pipeline |
| CN113588408B (en) * | 2021-08-31 | 2022-06-10 | 中国矿业大学 | Improved cylindrical concrete sample uniaxial tension fracture device and method |
| CN114486448B (en) * | 2022-02-17 | 2024-04-12 | 南京工程学院 | Manufacturing method of stretching soil sample multi-angle V or U-shaped crack |
| CN115615778B (en) * | 2022-09-27 | 2024-05-28 | 河海大学 | Method for horizontal uniaxial stretching of mixture of variable-particle-size gravel and clay |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201266196Y (en) * | 2008-10-17 | 2009-07-01 | 东南大学 | Uniaxial drawing loading unit for tension stress lower concrete carbonizing performance |
| CN202582979U (en) * | 2012-01-17 | 2012-12-05 | 西北农林科技大学 | Soil sample uniaxial direct tensioning device |
| CN105043877A (en) * | 2015-08-26 | 2015-11-11 | 长江水利委员会长江科学院 | Novel tensile strength testing device for core sample |
| JP5954718B1 (en) * | 2015-02-12 | 2016-07-20 | 有限会社ディップ | Multi-axial tensile testing device |
| CN206002361U (en) * | 2016-08-12 | 2017-03-08 | 郑州大学 | Concrete direct tensile test test specimen, specimen molding mould and complexes |
| CN109374404A (en) * | 2018-11-02 | 2019-02-22 | 河海大学 | A kind of sample preparation device, method and the test method of geotechnique's tension test |
-
2020
- 2020-07-23 CN CN202010716525.0A patent/CN111982675B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201266196Y (en) * | 2008-10-17 | 2009-07-01 | 东南大学 | Uniaxial drawing loading unit for tension stress lower concrete carbonizing performance |
| CN202582979U (en) * | 2012-01-17 | 2012-12-05 | 西北农林科技大学 | Soil sample uniaxial direct tensioning device |
| JP5954718B1 (en) * | 2015-02-12 | 2016-07-20 | 有限会社ディップ | Multi-axial tensile testing device |
| CN105043877A (en) * | 2015-08-26 | 2015-11-11 | 长江水利委员会长江科学院 | Novel tensile strength testing device for core sample |
| CN206002361U (en) * | 2016-08-12 | 2017-03-08 | 郑州大学 | Concrete direct tensile test test specimen, specimen molding mould and complexes |
| CN109374404A (en) * | 2018-11-02 | 2019-02-22 | 河海大学 | A kind of sample preparation device, method and the test method of geotechnique's tension test |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111982675A (en) | 2020-11-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111982675B (en) | Test method for integral soil uniaxial tension device | |
| CN111965019B (en) | Visual integral type soil body unipolar stretching device breaks | |
| CN111982674B (en) | Height-adjustable soil body uniaxial stretching device with sliding rod | |
| CN111982673B (en) | Height-adjustable soil body uniaxial tensile test method with sliding rod | |
| CN108333046B (en) | Device for measuring mechanical property of membrane material and method for measuring by adopting device | |
| JP3684376B2 (en) | In-situ shear tester | |
| CN101105433A (en) | Portable on-spot and indoor dual-purpose direct-cutting experiment instrument and its sampling method | |
| CN103487315A (en) | Testing device for mechanical property of material | |
| RU2365916C1 (en) | Device for investigation of physical-mechanical characteristics of soil layer | |
| DE19938011C2 (en) | Two-dimensional stress relaxation test apparatus | |
| CN101603900B (en) | Self-balancing test device and method for directly testing axial tensile strength of early-age concrete | |
| CN111751217A (en) | Horizontal concrete uniaxial tensile test device and use method thereof | |
| Slowik et al. | Mixed mode fracture of cementitious bimaterial interfaces;: Part I: Experimental results | |
| CN115628976A (en) | Building material strength detection system and detection method | |
| CN103344468A (en) | Stress control type soil engineering sample pressing apparatus | |
| CN110646343A (en) | Confining pressure adjustable anchor rod test piece uplift resistance test device and method | |
| CN115876608A (en) | Rock-soil mechanics test device and method in-situ freeze thawing-dry-wet cycle environment | |
| Cattaneo et al. | Effect of different boundary conditions in direct tensile tests: experimental results | |
| CN115615848A (en) | Prestressed reinforcement impact protection test device and test method | |
| CN214427173U (en) | Concrete strength detection device suitable for bridge construction control | |
| CN107167377B (en) | Device and method for measuring tensile strength of soil body by using direct shear apparatus | |
| CN111458238B (en) | Assembled rock-soil body slope in-situ direct shear test device and method | |
| JP3603277B2 (en) | Tension measuring device and tension measuring method using the same | |
| CN109470565B (en) | Method for testing dynamic Poisson's ratio of asphalt mixture | |
| CN112964553A (en) | Cement soil uniaxial tension tester and testing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |