Calcareous sand triaxial test sample preparation device
By designing a triaxial test sample preparation device for calcium sand, using the combination of rubber film and exhaust holes, the problem of irregular sample forming and low saturation in traditional sample preparation methods is solved, and the effects of regular molding and high saturation are achieved.
Patent Information
- Application Number
- CN202421093482.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2025-04-15
- Estimated Expiration
- 2034-05-17
AI Technical Summary
The traditional triaxial test sample preparation method can easily lead to irregular sample forming and deviation of experimental results during the molding of calcium sand samples. Moreover, calcium sand is fragile. Multiple knocks will cause particles to break, affecting the mechanical properties; at the same time, the pores of calcium sand are difficult to completely eliminate, affecting the saturation test results.
A three-axis test sample preparation device for calcium sand is designed, including a base, sleeve and top cover. The rubber film and exhaust hole are used to form the sample by tapping the outside of the sleeve, and the gas inside the sample is removed by pumping and water injection to improve saturation.
The device can regularly mold calcium sand samples, avoid crushing problems caused by knocking, improve sample saturation, and ensure the accuracy of experimental results.
Smart Images
Figure CN222761943U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of sand soil testing, in particular to a calcareous sand triaxial test sample preparation device. Background Art
[0002] At present, triaxial test of sand is widely used in the detection of mechanical properties of sand. There are two methods for preparing sand samples for triaxial test: dry sampling and wet sampling. In dry sampling, multiple sand samples are knocked on the outside of the sample preparation tube to make them reach the same height and finally form a sample. In wet sampling, air-free water is added to multiple sand samples to stir them, and sand samples with the same water content are formed and then compacted. Multiple sand samples are at the same height and finally form a sample.
[0003] The traditional triaxial test uses a membrane cylinder and a three-petal compaction device to prepare samples. The outside of the membrane cylinder is knocked to compact the sand sample inside the membrane cylinder. However, the rubber membrane on the outside of the sample is difficult to fit tightly against the inner wall of the membrane cylinder during the sample preparation process, resulting in irregular sample formation when knocked, which in turn leads to deviations in the experimental results. To ensure the uniformity of sample formation, high operating requirements are placed on the operator, and multiple knocks are required. Due to the porous and fragile surface of calcareous sand, multiple knocks will break the calcareous sand particles, resulting in significant changes in the mechanical properties of the calcareous sand, which seriously affects the accuracy of the test. In addition, when conducting a saturation test on the sand sample, since the calcareous sand particles have abundant pores and gas remains inside the pores, it is difficult to obtain a final sample with a high saturation by directly injecting air-free water. Utility Model Content
[0004] The utility model aims to provide a calcareous sand triaxial test sample preparation device, which can fully remove residual gas in a sample, improve the saturation of the sample, and is suitable for preparing samples of calcareous sand.
[0005] In order to achieve the above-mentioned purpose, the utility model provides a calcareous sand triaxial test sample preparation device, comprising a base and a sleeve, wherein the base is provided with a first water permeable hole penetrating through the upper and lower surfaces thereof, and the upper end of the base is provided with a first water permeable plate; the lower end of the sleeve is sleeved on the outer periphery of the base, and the side of the sleeve is provided with an exhaust hole penetrating through the side wall of the sleeve; the sleeve is formed by splicing two semicircular arc pieces, and the side edges of the semicircular arc pieces are provided with matching grooves and protrusions, and a bonding mechanism for connection is provided between the two semicircular arc pieces; the upper end cover of the sleeve is provided with a top cover, and the top cover is provided with a second water permeable hole penetrating through the upper and lower surfaces thereof, and the lower end of the top cover is provided with a second water permeable plate; a cavity is formed between the top cover, the sleeve and the base;
[0006] A rubber membrane is provided inside the cavity and is attached to the inner wall of the sleeve. The upper end of the rubber membrane is sealed to the top cover, and the lower end of the rubber membrane is sealed to the base, so that the first water-permeable hole, the inner cavity of the rubber membrane and the second water-permeable hole are connected.
[0007] Preferably, the device further comprises an extraction device, and the extraction device is used to be connected to the first water permeable hole, the second water permeable hole or the exhaust hole.
[0008] Preferably, the bonding mechanism is vaseline.
[0009] Preferably, a fixing ring is provided at the lower end of the sleeve and is sleeved on the outer circumference of the sleeve.
[0010] Furthermore, the fixing ring is formed by splicing two semicircular rings.
[0011] Preferably, a bottom plate for support is provided at the lower end of the base.
[0012] The utility model embodiment is a calcareous sand triaxial test sample preparation device. Compared with the prior art, its beneficial effects are: by assembling and sleeve-mounting two semicircular arc pieces on the outer periphery of the base, a space for placing the calcareous sand sample is formed, and a rubber membrane is placed in the space enclosed by the sleeve and the base. During installation, the rubber membrane is attached to the upper end of the base and the inner wall of the sleeve, and the calcareous sand sample is placed in the rubber membrane; the outer side of the sleeve is tapped to make multiple samples of the same height, and the top of the sample is also sealed with a rubber membrane, and a top cover is covered; an external device is used to connect with the exhaust hole, and the gas between the sleeve and the rubber membrane is extracted to make the rubber membrane close to the sleeve, the top cover and the bottom cover, and then the external device is connected to the first water permeable hole Or the second water permeable hole is used for pumping air, and air-free water is injected into the first water permeable hole or the second water permeable hole that is not connected to the external device. The air-free water flows through the sample and is pumped out by the external device, so that the gas inside the sample is fully discharged, and the top cover provides pressure to compact the sample to complete the sample preparation; when preparing the sample, it is only necessary to tap lightly to make multiple samples of the same height, and the subsequent sample preparation process can be completed by pumping air and the pressure of the top cover. The rubber membrane is tightly attached to the sleeve and the base, and has a regular shape. There is no need to apply too much force to knock, which protects the calcareous sand sample from being easily damaged; while pumping air, air-free water is injected from the other end, and the air-free water fully flows through the inside of the sample and is then discharged, which can discharge the gas inside the sample and greatly improve the saturation of the sample preparation. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 It is an exploded view of a sample preparation device for a triaxial test of calcareous sand according to an embodiment of the utility model.
[0014] Figure 2 It is a cross-sectional view of the sample preparation device for the triaxial test of calcareous sand in an exploded state according to an embodiment of the utility model.
[0015] In the figure, 1, base; 11, first water permeable hole; 12, first water permeable plate; 2, sleeve; 21, semicircular arc piece; 211, groove; 212, raised portion; 22, exhaust hole; 3, top cover; 31, second water permeable hole; 32, second water permeable plate; 4, fixing ring; 41, semicircular ring; 5, bottom plate. DETAILED DESCRIPTION
[0016] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0017] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper" and "lower" in the present invention is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0018] like Figure 1 and Figure 2 As shown, a calcareous sand triaxial test sample preparation device according to a preferred embodiment of the utility model comprises a base 1 and a sleeve 2, wherein the base 1 is provided with a first water permeable hole 11 penetrating through the upper and lower surfaces thereof, and the upper end of the base 1 is provided with a first water permeable plate 12; the lower end of the sleeve 2 is sleeved on the outer periphery of the base 1, and the side of the sleeve 2 is provided with an exhaust hole penetrating through the side wall of the sleeve 2; the sleeve 2 is formed by splicing two semicircular arc pieces 21, and the side edges of the semicircular arc pieces 21 are provided with matching grooves 211 and protrusions 212, and a bonding mechanism for connection (not shown in the figure) is provided between the two semicircular arc pieces 21; the upper end cover of the sleeve 2 is provided with a top cover 3, and the top cover 3 is provided with a second water permeable hole 31 penetrating through the upper and lower surfaces thereof, and the lower end of the top cover 3 is provided with a second water permeable plate 32; a cavity is formed between the top cover 3, the sleeve 2 and the base 1;
[0019] A rubber membrane (not shown in the figure) is provided inside the cavity and is attached to the inner wall of the sleeve 2. The upper end of the rubber membrane is sealed with the top cover 3, and the lower end of the rubber membrane is sealed with the base 1, so that the first water permeable hole 11, the inner cavity of the rubber membrane and the second water permeable hole 31 are connected.
[0020] Specifically, the base 1 is placed vertically; the sleeve 2 is composed of two semicircular arc pieces 21, which are easy to install and disassemble. The two semicircular arc pieces 21 are sleeved on the outside of the base 1 through the groove 211 and the protrusion 212, so that the connection is more stable and the sealing is ensured; the top cover 3 is inserted into the sleeve 2 from the upper end of the sleeve 2, and the top cover 3 has a certain weight, which can apply pressure to shape the calcareous sand sample; the calcareous sand sample is placed in the rubber membrane, and the rubber membrane and the sample are placed in a cavity enclosed by the top cover 3, the sleeve 2 and the base 1. The length of the rubber membrane is greater than the length of the sleeve 2. The upper and lower ends of the rubber membrane are open and can be respectively sleeved on the sides of the top cover 3 and the base 1, so that the rubber membrane is sealed and fixed to ensure that the calcareous sand sample will not leak; a bonding mechanism is provided at the connection of the two semicircular arc pieces 21, so that the connection of the two semicircular arc pieces 21 is tighter, and the semicircular arc pieces 21 are prevented from separating during operation and causing sample preparation failure; the bonding mechanism can be disassembled or removed, and the sleeve 2 can be disassembled after the sample preparation is completed, which is convenient for subsequent operations;
[0021] The side of the sleeve 2 is provided with an exhaust hole 22, through which the gas between the rubber film and the sleeve 2 can be extracted, so that the rubber film is closely attached to the inner wall of the sleeve 2. Since the calcareous sand sample is formed by the rubber film, the rubber film is closely attached to the inner wall of the sleeve 2 and can be formed according to the shape of the rubber film, so that the final sample is formed into a regular shape;
[0022] The first water-permeable hole 11 is a through hole opened on the bottom surface of the base 1, and airless water can be injected through the first water-permeable hole 11 and flow out from the upper end of the base 1. The second water-permeable hole 31 is opened at the upper end of the top cover 3, and the second water-permeable hole 31 is communicated with the bottom of the top cover 3, so that liquid and gas can pass through. After the calcareous sand sample is formed, airless water is injected from the first water-permeable hole 11, and the injected airless water fills the gap of the calcareous sand from the lower end of the sample upward, and the gas inside the sample is squeezed by the airless water and discharged from the second water-permeable hole 31 above. When the airless water reaches the position of the top cover 3, the exhaust is completed, so that the saturation of the calcareous sand sample is greatly improved;
[0023] A first water-permeable plate 12 is provided at the upper end of the base 1. The diameter of the first water-permeable plate 12 is the same as that of the base, and the small holes in the first water-permeable plate 12 are connected to the first water-permeable holes 11. When the first water-permeable holes 11 are injected with air-free water, the air-free water enters from the lower end of the first water-permeable plate 12 and evenly seeps out from the upper end of the first water-permeable plate 12 into the calcareous sand sample, ensuring that the air-free water soaks the sample from bottom to top, preventing gas residue and increasing the sample saturation;
[0024] A second water-permeable plate 32 is provided at the lower end of the top cover 3. Specifically, the diameter of the second water-permeable plate 32 is the same as that of the top cover 3, and a plurality of small holes are evenly provided on the surface thereof, which are connected to the second water-permeable holes 31; the gas moving upward to the upper surface of the sample can be directly discharged through the small holes on the surface of the second water-permeable plate 32; if only the second water-permeable holes 31 are provided, the gas at the edge cannot be discharged smoothly, resulting in a low saturation at the top of the sample.
[0025] By utilizing an external device to connect the exhaust hole 22 to evacuate air and the pressure provided by the top cover 3, the sample can be regularly shaped to avoid the calcareous sand from being broken due to repeated knocking; by simultaneously filling with water and exhausting air, the saturation of the sample can be greatly improved.
[0026] Preferably, the device further comprises an extraction device, and the extraction device is used to be connected to the first water permeable hole, the second water permeable hole or the exhaust hole.
[0027] Specifically, an extraction device is provided to be connected to the exhaust hole 22 to extract the air between the rubber membrane and the inner wall of the sleeve 2, so that the rubber membrane is tightly attached to the inner wall of the sleeve 2; when air-free water is injected from the first water permeable hole 11, the extraction device is connected to the second water permeable hole 31 to extract the gas inside the cavity, which can greatly improve the exhaust effect and increase the sample saturation.
[0028] Furthermore, the bonding mechanism is vaseline. Vaseline can be applied to the connection between the two semicircular arc pieces 21 to ensure the stability and sealing of the connection, and it is also easy to remove when the sleeve 2 is removed; and vaseline can also be applied to other positions that need to be sealed, such as the connection between the rubber membrane and the base 1, the top cover 3, and the upper and lower ends of the sleeve 2 and the rubber membrane, which can greatly improve the sealing of the entire device.
[0029] Preferably, after the rubber membrane is sleeved on the sides of the top cover 3 and the base 1 , a rubber sleeve may be sleeved on the outside of the rubber membrane to fix the rubber membrane.
[0030] Preferably, a fixing ring 4 sleeved on the outer circumference of the sleeve 2 is provided at the bottom end of the sleeve 2; and the fixing ring 4 is composed of two semicircular rings 41.
[0031] Specifically, two semicircular rings 41 are spliced and sleeved on the bottom periphery of the sleeve 2 after installation. The diameter of the fixing ring 4 is slightly smaller than the outer diameter of the sleeve 2 so as to abut against the outer periphery of the sleeve 2 to ensure that the sample will not leak from the bottom of the sleeve 2 during the loading process.
[0032] Preferably, a bottom plate 5 for support is provided at the lower end of the base 1. The bottom plate 5 is placed at the bottom of the device, and the base 1 is placed on the bottom plate 5 to complete the sample preparation work.
[0033] The working process of the utility model is as follows: four calcareous sand samples of equal mass are weighed in advance, and the calcareous sand samples and the first water-permeable plate 12 are immersed in air-free water to remove the gas in the gap between the samples and the water-permeable plate;
[0034] Place the base 1 on the bottom plate 5, and lay the first water-permeable plate 12 on the base 1; then apply vaseline on the joints of the semicircular arc pieces 21, splice the two semicircular arc pieces 21 to form a sleeve 2, and after confirming that the sealing is intact, place the rubber membrane inside the sleeve 2, and fold the two ends of the rubber membrane to fix them on the two end outer walls of the sleeve 2 for easy subsequent installation; sleeve the bottom end of the sleeve 2 and the rubber membrane on the periphery of the base 1 and the first water-permeable plate 12, and after the rubber membrane is sleeved on the base 1, put the rubber membrane under The excess part of the end is folded and re-mounted on the outer wall of the bottom end of the sleeve 2 to ensure that a closed space is formed between the sleeve 2 and the base 1; then the calcareous sand sample is placed in the rubber membrane of the cavity part, and the outside of the sleeve 2 is tapped to make the heights of the four samples consistent. Then, the top cover 3 is placed into the sleeve 2 from the upper end of the sleeve 2, abutting against the upper surface of the sample, and after the upper end of the rubber membrane is sheathed to the outer periphery of the top cover 3, the excess part of the upper end of the rubber membrane is folded and re-sheathed on the top outer wall of the sleeve 2 to ensure sealing;
[0035] The extraction device is connected to the exhaust hole 22, and the extraction device is started. The air between the rubber membrane and the inner wall of the sleeve 2 is extracted through the exhaust hole 22. The air pressure in the rubber membrane is relatively large, so that the rubber membrane is closely attached to the inner wall of the sleeve 2. The calcareous sand sample is evenly distributed around the rubber membrane to ensure that the shape of the rubber membrane is regular. The top cover 3 provides a certain pressure to shape the calcareous sand sample.
[0036] After the calcareous sand sample is formed, the exhaust hole 22 is closed, and then the extraction device is connected to the second water permeable hole 31, and air-free water is injected from the first water permeable hole 11. The air-free water fills the calcareous sand sample from bottom to top, and the extraction device is started to continuously extract gas from the second water permeable hole 31, so that the gas in the sample is fully discharged and the saturation of the sample is increased;
[0037] After completion, the sleeve 2 and the top cover 3 are removed to obtain the calcareous sand sample required for the triaxial test.
[0038] In summary, the embodiment of the utility model provides a calcareous sand triaxial test sample preparation device, which extracts the internal gas of the sleeve 2 and the pressure applied by the top cover 3 through an extraction device, so that the sample can be formed according to the shape rules of the rubber film without multiple knocks, thereby preventing the calcareous sand from being broken by knocking; by injecting air-free water from the bottom and pumping air from the top, the gas in the sample can be repeatedly discharged, effectively improving the saturation of the calcareous sand sample; and by providing an annular groove and applying vaseline at the connection, the sealing of the device is greatly improved.
[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.
Claims
1. A sample preparation device for triaxial test of calcareous sand, characterized in that: The invention comprises a base and a sleeve, wherein the base is provided with a first water-permeable hole penetrating through the upper and lower surfaces thereof, and the upper end of the base is provided with a first water-permeable plate; the lower end of the sleeve is sleeved on the outer periphery of the base, and the side of the sleeve is provided with an exhaust hole penetrating through the side wall of the sleeve; the sleeve is formed by splicing two semicircular arc pieces, and the side edges of the semicircular arc pieces are provided with matching grooves and protrusions, and a bonding mechanism for connection is provided between the two semicircular arc pieces; the upper end cover of the sleeve is provided with a top cover, and the top cover is provided with a second water-permeable hole penetrating through the upper and lower surfaces thereof, and the lower end of the top cover is provided with a second water-permeable plate; a cavity is formed between the top cover, the sleeve and the base; A rubber membrane is provided inside the cavity and is attached to the inner wall of the sleeve. The upper end of the rubber membrane is sealed to the top cover, and the lower end of the rubber membrane is sealed to the base, so that the first water permeable hole, the inner cavity of the rubber membrane and the second water permeable hole are connected.
2. The calcareous sand triaxial test sample preparation device according to claim 1, characterized in that: It also includes an extraction device, which is used to be connected to the first water permeable hole, the second water permeable hole or the exhaust hole.
3. The calcareous sand triaxial test sample preparation device according to claim 1, characterized in that: The bonding mechanism is vaseline.
4. The calcareous sand triaxial test sample preparation device according to claim 1, characterized in that: The lower end of the sleeve is provided with a fixing ring which is sleeved on the outer circumference of the sleeve.
5. The calcareous sand triaxial test sample preparation device according to claim 4, characterized in that: The fixing ring is formed by splicing two semicircular rings.
6. The calcareous sand triaxial test sample preparation device according to claim 1, characterized in that: A bottom plate for support is provided at the lower end of the base.