Continuous testing device for three-dimensional volumetric shrinkage characteristics of soil

Abstract

This invention provides a continuous testing device for the three-dimensional volumetric shrinkage characteristics of soil, belonging to the technical field of geotechnical testing equipment. It includes: a transparent outer casing to form a sealed testing space; a graduated inner measuring cylinder containing a polymer solution for measuring sample volume, which also has a weighing function; a sample placement rod with a hydrophobic coating sprayed on both the inside and outside of the testing space, and a lifting handle; the sample can be completely immersed in or pulled out of the polymer solution by adjusting its longitudinal position; a fixing ring for fixing the position of the sample placement rod; and a base for supporting the upper device. This invention features a simple structure, reliable performance, and high testing accuracy. The test data can more accurately reflect the shrinkage characteristics of the soil under test. If the transparent outer casing is connected to a temperature and humidity controller, the testing device can obtain the shrinkage characteristics of soil under different temperature and humidity environments without disturbing the soil, effectively reducing errors during the testing process and improving testing efficiency.

Description

Technical Field

[0001] This utility model relates to the field of geotechnical testing equipment technology, specifically to a continuous testing device for the three-dimensional volumetric shrinkage characteristics of soil. Background Technology

[0002] Determining the shrinkage characteristics of soil is fundamental to the study of unsaturated soils. During soil shrinkage due to water loss, the moisture field redistributes, significantly altering the soil's physicochemical, hydrological, and mechanical properties. Furthermore, changes in temperature and humidity in the real environment also affect the accuracy of soil shrinkage characteristic measurements. In geotechnical engineering, existing soil shrinkage characteristic testing devices have the following shortcomings: they rely solely on single-location displacement to represent shrinkage, failing to accurately describe the three-dimensional volumetric shrinkage of the soil; they require the preparation of parallel samples for measurement, resulting in cumbersome procedures and difficulty in eliminating sample preparation errors; and they cannot be used to complete measurements under consistently stable temperature and humidity conditions. Utility Model Content

[0003] The purpose of this invention is to provide a continuous testing device for soil shrinkage characteristics that can effectively improve testing accuracy and efficiency. It can realize continuous measurement of the actual shrinkage deformation of the sample under constant temperature and humidity, so as to solve at least one of the technical problems existing in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] This utility model provides a continuous testing device for the three-dimensional volumetric shrinkage characteristics of soil, comprising:

[0006] A base; a transparent cover is provided on the base; the transparent cover includes a cover body and a central opening at the top, the opening is fitted with a rubber sleeve, and the transparent cover can form a sealed test space;

[0007] The measuring inner cylinder is set inside a transparent outer cover. The measuring inner cylinder has graduations engraved on its side wall and an electronic balance is installed at the bottom of the measuring inner cylinder.

[0008] The sample placement rod passes through the opening of the transparent outer cover and has a lifting handle at the top. It is connected to the sample placement frame through a rigid support rod. The sample placement frame is located at the bottom to support the sample. The sample placement rod can move longitudinally.

[0009] A fixing ring, the outer diameter of which is larger than that of the transparent outer cover and the inner diameter of which is larger than that of the sample rod, can fix the longitudinal position of the sample rod when the fixing bolt is tightened.

[0010] Furthermore, the transparent outer cover and the base form a sealed test space. The polymer solution in the inner cylinder of the test space is used to precipitate moisture from the sample and measure the volume and mass of the sample. The sample placement rod can completely immerse or remove the sample from the polymer solution without deformation.

[0011] Furthermore, the transparent outer cover includes a transparent cover body with an opening at the center of the top. The diameter of the opening is slightly larger than that of the sample rod, and a sealing sleeve is provided inside the opening.

[0012] Furthermore, the measuring inner cylinder has a body that can hold a polymer solution, the side wall of the body is provided with graduations, and the bottom of the measuring inner cylinder has an electronic balance that can measure the overall mass of the internal solution when the liquid level changes.

[0013] Furthermore, the top of the sample placement rod is provided with a lifting handle to facilitate the longitudinal movement of the sample placement rod. The middle support rod passes through the top opening of the transparent outer cover, and the lower part of the support rod is connected to the bottom sample holder. The sample holder has a mesh structure, and the bottom mesh of the sample holder is larger than the sample size, so it can carry the sample and move it longitudinally.

[0014] Furthermore, the fixing ring consists of a fixing ring body and a fixing bolt. The outer diameter of the fixing ring is larger than the opening at the top of the transparent cover. One part of the inner side of the fixing ring is a groove adapted to the diameter of the sample rod, and the other part is a cavity with a horizontal thread. The bottom of the fixing ring body has space to accommodate the rubber sleeve. The fixing bolt can be screwed into the ring body through the horizontal thread to achieve the effect of locking the sample rod.

[0015] Furthermore, the base is a platform with both the top and bottom surfaces being horizontal. The top part is provided with a positioning transparent outer cover and a groove for the measuring inner cylinder. The base is used to provide support for other device components and ensure that the device is placed horizontally.

[0016] The advantages of this invention are: it is used to determine the three-dimensional volumetric deformation of soil shrinkage process, avoids the influence of sample preparation error caused by using parallel samples, can accurately determine the soil shrinkage characteristics, and provides a stable testing environment, eliminating the influence of temperature and humidity changes caused by changes in testing location.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a structural diagram of the continuous testing device for three-dimensional volumetric shrinkage characteristics of soil according to an embodiment of the present invention.

[0020] Figure 2This is a structural diagram of the sample holder for the continuous testing device for three-dimensional volumetric shrinkage characteristics of soil as described in an embodiment of this utility model.

[0021] Figure 3 This is a structural diagram of the fixed ring of the continuous testing device for three-dimensional volumetric shrinkage characteristics of soil according to an embodiment of this utility model.

[0022] Figure 4 This is a structural diagram of the base of the continuous testing device for three-dimensional volumetric shrinkage characteristics of soil as described in an embodiment of this utility model.

[0023] Figure 5 This is a schematic diagram of the preparation of a continuous test specimen for soil shrinkage characteristics according to an embodiment of this utility model.

[0024] Figure 6 This is a schematic diagram of the working state of the soil shrinkage characteristic continuous testing device that can realize three-dimensional volumetric deformation measurement and eliminates the need for parallel samples, as described in the embodiments of this utility model.

[0025] The components include: 1. Transparent outer cover; 101. Transparent cover body; 102. Opening with rubber sleeve; 2. Measuring inner cylinder; 201. Cylinder body; 202. Scale; 203. Electronic balance; 204. Polymer solution; 3. Sample placement rod; 301. Lifting handle; 302. Support rod; 303. Top net of sample placement rack; 304. Connecting rod of sample placement rack; 305. Bottom net of sample placement rack; 4. Fixing ring; 401. Fixing ring body; 402. Fixing bolt; 403. Support rod groove; 404. Bolt hole; 5. Base; 501. Base body; 502. Reserved groove of transparent outer cover; 503. Reserved groove of measuring inner cylinder. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0027] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as here.

[0029] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the word “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.

[0030] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the described specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0031] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In the description of this specification, the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this technology and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this technology.

[0033] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of these terms in this art according to the specific circumstances.

[0034] To facilitate understanding of this utility model, the present utility model will be further explained and described below with reference to the accompanying drawings and specific embodiments. The specific embodiments do not constitute a limitation on the embodiments of this utility model.

[0035] Those skilled in the art should understand that the accompanying drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily essential for implementing this utility model.

[0036] like Figures 1 to 6 As shown in this embodiment, a continuous testing device for soil shrinkage characteristics that can realize three-dimensional volumetric deformation measurement and eliminates the need for parallel samples is provided. The device includes: a transparent outer cover, which includes a cover body and a central opening at the top. The opening is fitted with a rubber sleeve. The transparent outer cover can form a sealed testing space and observe the test process; a measuring inner cylinder, which is set inside the transparent outer cover and is used to hold a polymer solution. The measuring inner cylinder has graduations on its side walls for recording changes in the volume of the liquid inside. An electronic balance is located at the bottom for measuring the mass of the contents of the inner cylinder; and a sample placement rod, which passes through the transparent outer cover. The outer cover has openings and a lifting handle at the top, which connects to the top net of the sample holder via a rigid support rod. The bottom net of the sample holder is located at the bottom to support the sample. The sample holder rod can move longitudinally to allow the sample to be completely immersed in or pulled out of the polymer solution. The sample holder is coated with a hydrophobic coating to prevent solution adhesion when the polymer solution is pulled out. A fixing ring has an outer diameter larger than the transparent outer cover and an inner diameter larger than the diameter of the sample holder rod. Tightening the fixing bolts can fix the longitudinal position of the sample holder rod. A base supports all device components, provides a stable testing foundation, and ensures that the testing device remains level.

[0037] In one specific embodiment, the transparent outer cover is square, with a width that can accommodate the measuring inner cylinder and a height sufficient to adjust the sample rod so that the sample is completely detached from the polymer solution. It can be made of acrylic or glass to observe and record the entire test process. The top center opening is slightly larger than the diameter of the sample rod and is equipped with a rubber sleeve to ensure the sealing effect when the sample rod moves and is fixed. At the same time, the transparent outer cover should have a certain strength to support the fixed sample rod and the sample.

[0038] In one specific embodiment, the diameter of the measuring inner cylinder is smaller than the width of the transparent outer cover, and it has the function of holding a polymer solution. The volume of the measuring inner cylinder needs to be pre-measured and marked with a scale, and the accuracy of the scale should meet the test requirements. The selected polymer solution is stable in nature, can release soil moisture, and can be isolated by the semi-permeable membrane covering the soil to prevent it from seeping into the soil. An electronic balance is located at the bottom of the measuring inner cylinder, which can measure the mass of the contents of the inner cylinder in real time.

[0039] In one specific embodiment, the sample placement rod is made of rigid material and has a lifting handle at the top for easy control of the overall longitudinal displacement of the sample placement rod. The force-bearing rod should fit well with the rubber sleeve with the opening in the transparent outer cover. The lower part of the force-bearing rod is connected to the top net of the sample placement frame. During the test, the liquid level of the polymer solution is recorded. The sample placement frame should be larger than the sample size and be sprayed with a hydrophobic coating to avoid adhesion to the polymer solution. The volume and mass of the sample placement frame need to be determined in advance so as to eliminate the problem in subsequent calculations.

[0040] In one specific embodiment, the fixing ring is cylindrical and can fix the position of the sample rod by fixing bolts. The bottom of the ring has a reserved space to accommodate the rubber sleeve and contacts the transparent outer cover to provide force to counteract the mass of the sample rod and the sample. The interior part is a groove adapted to the sample rod and a cavity with threaded holes, so that the sample rod can be loosened and locked by rotating the fixing bolts.

[0041] In one specific embodiment, the base is a platform with a transparent outer cover and a groove at the top for fixing the measuring inner cylinder, which can support all test components and ensure that the test device is level.

[0042] In one specific embodiment, the temperature and humidity control device can be connected to the test space formed by the test device, thereby controlling the temperature and humidity of the test.

[0043] In this embodiment, the soil shrinkage characteristic is collected using the above-mentioned continuous soil shrinkage characteristic testing device and then calculated using the buoyancy conversion method. The calculation method includes: the initial mass of the sample is obtained by weighing before immersion, and the initial volume of the sample is obtained by the volume of liquid drained after immersion; the water loss mass after soil shrinkage is obtained by the difference between the electronic balance before and after immersion, and the soil shrinkage volume is obtained by the buoyancy before and after immersion and the volume of drained water; the density of the polymer solution can be calibrated by measuring the difference between the inner cylinder scale and the initial buoyancy.

[0044] The method of using the soil shrinkage characteristic testing device is as follows: First, weigh the soil sample and place it on the sample rack wrapped with a semi-permeable membrane; then tighten the fixing ring to fix the rack and record the mass and volume of the solution in the inner cylinder; then adjust the position of the sample rod to completely immerse the sample in the polymer solution and calculate the initial volume of the sample; wait for the soil water to be extracted, and when the preset measurement time is reached, lift the sample until it is completely removed from the polymer solution, record the reading of the electronic balance, then completely immerse the sample in the polymer solution again, record the reading of the electronic balance, and calculate the soil shrinkage volume; repeat the previous steps until the test is completed; if temperature and humidity conditions are set, they need to be controlled in advance before the test to ensure that the temperature and humidity in the test space are stable before the test is carried out; subsequent tests can be reset to conduct other group tests.

[0045] This method is used to determine the three-dimensional volumetric strain of soil shrinkage, avoiding the sample preparation errors caused by using parallel samples. It can accurately determine the characteristics of soil shrinkage and provides a stable testing environment, eliminating the influence of temperature and humidity changes caused by changes in the testing location.

[0046] In one embodiment, see Figure 1 As shown, Figure 1 This is a schematic diagram of the main body of a continuous soil shrinkage characteristic testing device, which includes a transparent outer cover 1, a measuring inner cylinder 2, a sample placement rod 3, a fixing ring 4, and a base 5.

[0047] The transparent outer cover 1 is provided with a transparent cover body 101. Optionally, the transparent cover body 101 is made of glass or acrylic material and has the function of observing the test status and supporting the sample rod 3. A rubber sleeve opening 102 is provided at the center of its top, and the size of the opening allows the sample rod to move longitudinally.

[0048] The inner measuring cylinder 2 is located inside the outer cover 1, and the bottom is an electronic balance 203 used to weigh the contents. The side wall of the cylinder 201 is engraved with a scale 202 for calculating the liquid level and volume. Inside the cylinder 201 is a polymer solution 204 for precipitating water from the soil.

[0049] The sample placement rod 3 has a lifting handle 301 at its top, located outside the transparent outer cover 1. The support rod 302 has a diameter slightly smaller than the rubber-sleeved opening 102 at the top of the transparent outer cover 1. It is a rigid structure. The bottom of the support rod 302 is connected to the top mesh 303 of the sample placement rack. The bottom mesh 305 of the sample placement rack has a large-pore mesh to prevent the polymer solution from adhering. The top mesh 303 and the bottom mesh 305 of the sample placement rack are connected. Figure 2 The two are connected by a sample holder connecting rod 304, and the relevant structure has a certain strength to support the sample.

[0050] Among them, the fixed ring 4 is as follows Figure 3 As shown, the diameter of the fixing ring 401 is larger than the diameter of the opening 102 with rubber sleeve, which can clamp the sample rod 3 and fix it on the transparent outer cover 1. The force-bearing rod groove 403 is adapted to the force-bearing rod 302. The fixing bolt 402 can lock or loosen the sample rack 3 through the bolt hole 404.

[0051] Among them, base 5, as Figure 4 As shown, the base body 501 is used to provide a stable horizontal platform for the device, and the top has a transparent outer cover reserved slot 502 to adapt to the transparent outer cover 1 and a measuring inner cylinder reserved slot 503 to adapt to the measuring inner cylinder 2.

[0052] In one embodiment, a method for continuous testing of soil shrinkage characteristics is provided, specifically, in conjunction with... Figures 1 to 5 As shown, the usage method includes:

[0053] Step 1: First, prepare a soil sample wrapped in a semi-permeable membrane, such as... Figure 5 As shown, first fix the semi-permeable membrane to the bottom impermeable plate ( Figure 5 (P1), then add a sample preparation mold, and divide the soil into compacted samples according to the test requirements ( Figure 5 (P2), then cover with an impermeable sheet, and tighten the semi-permeable membrane and the impermeable sheet together with a hoop. Figure 5 After completing the sample preparation (P3), the sample is weighed.

[0054] Step 2: Adjust the position of the sample rod to completely immerse the sample in the polymer solution and calculate the initial volume of the sample, such as... Figure 6 As shown in S1;

[0055] Step 3: Wait for the soil water to be extracted. When the preset measurement time has been reached, lift the sample until it is completely separated from the polymer solution, such as... Figure 6 As shown in S2, record the reading of the electronic balance, then completely immerse the sample in the polymer solution, as shown. Figure 6 As shown in S1, record the reading of the electronic balance and calculate the soil shrinkage volume;

[0056] Step 4: Repeat the previous step until the test is finished.

[0057] Step 5: Based on the recorded data, calculate the soil drainage mass and shrinkage volume, and plot the curves.

[0058] Specifically, in this embodiment, the earth pressure testing device is recalibrated to zero before the next set of tests.

[0059] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that, based on the technical solutions disclosed in the present utility model, all modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present utility model.

Claims

1. A device for continuous testing of three-dimensional volume change and shrinkage characteristics of soil mass, characterized in that, include: A base; the base is provided with a transparent cover; the transparent cover includes a cover body and a central opening at the top, the opening is covered with a rubber sleeve, and the transparent cover can form a sealed test space; The measuring inner cylinder is set inside a transparent outer cover. The measuring inner cylinder has graduations engraved on its side wall and an electronic balance is installed at the bottom of the measuring inner cylinder. The sample placement rod passes through the opening of the transparent outer cover and has a lifting handle at the top. It is connected to the sample placement frame through a rigid support rod. The sample placement frame is located at the bottom to support the sample. The sample placement rod can move longitudinally. A fixing ring, the outer diameter of which is larger than that of the transparent outer cover and the inner diameter of which is larger than that of the sample rod, can fix the longitudinal position of the sample rod when the fixing bolt is tightened.

2. The apparatus of claim 1, wherein, The transparent outer cover and the base form a sealed test space. The polymer solution in the inner cylinder of the test space is used to precipitate moisture from the sample and measure the volume and mass of the sample. The sample placement rod can completely immerse or remove the sample from the polymer solution without deformation.

3. The apparatus of claim 2, wherein, The transparent outer cover includes a transparent cover body with an opening at the center of the top. The diameter of the opening is slightly larger than that of the sample rod, and a sealing sleeve is installed inside the opening.

4. The apparatus of claim 1, wherein, The measuring inner cylinder has a body that can hold polymer solutions. The side wall of the body is marked with graduations. The bottom of the measuring inner cylinder has an electronic balance that can measure the overall mass of the solution when the internal liquid level changes.

5. The apparatus of claim 1, wherein, The top of the sample placement rod is equipped with a lifting handle for easy control of the longitudinal movement of the sample placement rod. The middle support rod passes through the top opening of the transparent outer cover, and the lower part of the support rod is connected to the bottom of the sample placement frame. The sample placement frame has a mesh structure, and the bottom mesh of the sample placement frame is larger than the sample size, so it can carry the sample and move it longitudinally.

6. The continuous testing device for three-dimensional volumetric shrinkage characteristics of soil according to claim 1, characterized in that, The fixing ring consists of a fixing ring body and a fixing bolt. The outer diameter of the fixing ring body is larger than the opening at the top of the transparent cover. One part of the inner side of the fixing ring body is a groove adapted to the diameter of the sample rod, and the other part is a cavity with a horizontal thread. The bottom of the fixing ring body has space to accommodate a rubber sleeve. The fixing bolt can be screwed into the ring body through the horizontal thread to achieve the effect of locking the sample rod.

7. The continuous testing device for three-dimensional volumetric shrinkage characteristics of soil according to claim 1, characterized in that, The base is a platform with a horizontal top and bottom surface. The top part is provided with a positioning transparent outer cover and a groove for the measuring inner cylinder. The base is used to provide support for other device components and to ensure the horizontal placement of the device.

Images