Demoulding and sample loading device for remolded saturated soft soil triaxial sample and use method of demoulding and sample loading device

Abstract

The invention discloses a demolding and sample loading device for a remolded saturated soft soil triaxial sample and a use method of the demolding and sample loading device, and relates to the technical field of triaxial tests, and the demolding and sample loading device for the remolded saturated soft soil triaxial sample comprises a saturator, a turnover device, a sample loading part and a demolding part. Compared with the prior art, the demolding component can transfer a soft soil sample subjected to vacuum saturation from the saturator to the turnaround device, the soil sample is clamped between the upper bearing platform and the lower bearing platform, and disturbance of the sample is reduced to the maximum extent; the sample loading part can ensure that the soft soil sample is not influenced by gravity and pressure when the back pressure cap and the supporting rod are arranged after the sample is mounted on the triaxial apparatus, the problem that the triaxial sample loses stability or loses stability when being pressed after being loaded is solved, meanwhile, enough space is reserved for the sample to deform when being pressed, and the success rate of the triaxial test is improved.

Description

Technical Field

[0001] The present application relates to the technical field of triaxial testing, and in particular to a demoulding and sampling device for reshaping a saturated soft soil triaxial specimen and a method for using the same. Background Art

[0002] Soft soil generally refers to saturated clay soil with a natural water content greater than the liquid limit and a natural porosity greater than 1, including silt, silty soil, peat, and peaty soil. In recent years, with economic development, infrastructure construction has been carried out on a large scale in coastal areas and river and lake areas. From ultra-wide river immersed tube tunnels to large-scale coastal area development, research on saturated soft soil is indispensable. Soft soil has high compressibility, low shear strength, and poor permeability. When carrying out engineering construction on soft soil foundations, it is necessary to obtain the basic mechanical properties of soft soil. Triaxial testing can simulate the complex stress conditions of soil in actual engineering. Its highly controllable stress conditions, comprehensive parameter measurement, and wide applicability have become the core means of studying the mechanical behavior of soil, providing an important basis for engineering design and theoretical research. The key to the success of triaxial testing is to successfully install the soil in the triaxial apparatus without disturbance.

[0003] Existing triaxial testing sample loading techniques primarily include: 1. Using a barrel and rubber membrane to install triaxial specimens; 2. Using a two-valve membrane to install triaxial specimens; and 3. Using a two-valve membrane with a rubber tube. Due to the inherently poor mechanical properties of soft soil, especially for reshaped soft soil specimens with low dry density, existing sample loading techniques can damage the reshaped saturated soft soil during demolding after vacuum saturation, resulting in a low demolding success rate. Even if demolding is successful, the reshaped saturated soft soil is susceptible to damage during sample loading due to its high rheological properties. Under the combined effects of its own gravity, the back pressure cap, and the triaxial test rod, the reshaped saturated soft soil is easily damaged, resulting in experimental failure. Due to the high cost and long test cycle of triaxial testing, experimental failures can lead to a significant waste of manpower and financial resources. Summary of the Invention

[0004] The present application aims to solve one of the above-mentioned technical problems in the prior art. To this end, an embodiment of the present application provides a demoulding and sampling device for reshaping a saturated soft soil triaxial specimen.

[0005] The embodiment of the present application also provides a method for using a demolding and sampling device for reshaping a saturated soft soil triaxial specimen.

[0006] According to an embodiment of the first aspect of the present application, there is provided a demoulding and sampling device for reshaping a saturated soft soil triaxial specimen, comprising a saturator for shaping the saturated soft soil specimen;

[0007] The turnover device includes a first molded part, a second molded part, and a flexible connector, wherein the first molded part and the second molded part are connected by the flexible connector to form a sample loading slot;

[0008] A demolding component includes a first support, a second support, and a transfer assembly, wherein the central axes of the first support and the second support are collinear, and the distance between the first support and the second support is equal to the height of the turnover device, wherein the middle portions of the first support and the second support are each provided with an avoidance hole, the first support is used to support the saturator, and the second support is used to support the turnover device, and the soft soil sample in the saturator is transferred to the sample loading slot of the turnover device via the transfer assembly;

[0009] The sample loading component includes a sample loading seat and a retractable positioning seat. After the flexible connector is docked with the sample loading seat, the turnover device is docked with the positioning seat. After the restriction of the flexible connector on the first and second molded parts is released, the first and second molded parts are driven to separate through the positioning seat, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat.

[0010] The demolding and sampling device for reshaping saturated soft soil triaxial specimens has at least the following beneficial effects: a vacuum method is adopted to cooperate with the saturator to realize the molding of the saturated soft soil specimen; during demolding, the saturator with the saturated soft soil specimen is placed on the first support platform, and the revolver is placed on the second support platform, and the saturator and the revolver are docked in an upper and lower state; the saturated soft soil specimen in the saturator is transferred from the avoidance hole to the sampling slot of the revolver through the transfer component, thereby ensuring that the saturated soft soil specimen is not damaged or deformed by its gravity and external pressure; after the saturated soft soil specimen is transferred to the revolver, the revolver is transferred to the sampling seat of the sampling component, and after the flexible connector is docked with the sampling seat, the positioning seat is docked with the first mold part or the second mold part, and after the restriction of the flexible connector on the first mold part and the second mold part is released, the first mold part and the second mold part are driven to separate by the positioning seat, so that the saturated soft soil specimen wrapped by the flexible connector is positioned on the sampling seat. Compared with the existing technology, the demoulding component of the present application can transfer the soft soil sample after vacuum saturation from the saturator to the turnover device, and the upper and lower platforms clamp the soil sample in the middle, thereby minimizing the disturbance of the sample; the loading component can ensure that after the sample is installed on the triaxial apparatus, when the back pressure cap and the support rod are installed, the soft soil sample is protected from its gravity and pressure, thereby solving the problem of the triaxial sample itself becoming unstable or becoming unstable under pressure after loading, and at the same time leaving enough space for the sample to deform under pressure, thereby improving the success rate of the triaxial test.

[0011] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the first mold member and the second mold member are combined to form a hollow cylinder, and the end of the cylinder is fixed by the flexible connecting member so that the flexible connecting member fits into the inner wall of the cylinder, thereby forming the sampling groove.

[0012] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the flexible connecting member is cylindrical, and the end of the flexible connecting member is turned outward to wrap the end surface of the cylinder, and the first mold member and the second mold member are connected together through the elastic deformation of the flexible connecting member.

[0013] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the flexible connector is made of rubber, and a docking channel is provided on the outside of the first molded part or the second molded part. The docking channel is connected to the interior of the cylinder, and the air between the inner wall of the cylinder and the flexible connector is extracted through the docking channel to make the flexible connector fit the inner wall of the cylinder.

[0014] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the end faces of the first molded part and the second molded part are each provided with at least two first docking holes, and the positioning seat is provided with second docking holes that are the same in number and corresponding in position to the first docking holes. After the first docking holes are aligned with the second docking holes, the first molded part or the second molded part is positioned on the positioning seat by means of pins passing through the first docking holes and the second docking holes.

[0015] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the first aspect of the embodiment of the present application, the transfer assembly includes a first pressure plate, a second pressure plate, and a driving member that can be raised and lowered in a direction parallel to the central axis of the avoidance hole. The central axes of the first pressure plate, the second pressure plate, the first support platform, and the second support platform are collinear, the distance between the first pressure plate and the second pressure plate is equal to the height of the revolver, and the first pressure plate and the second pressure plate are driven to move synchronously by the driving member.

[0016] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the driving member includes a first connecting rod and a second connecting rod, the first connecting rod and the second connecting rod both include a horizontal section and a vertical section, the ratio of the distance between the two horizontal sections to the height of the revolver is greater than 2, the vertical section is collinear with the central axis of the avoidance hole, the first pressure plate is arranged on the first connecting rod, and the second pressure plate is arranged on the second connecting rod.

[0017] According to the demolding and sampling device for reshaped saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the positioning seats are provided with two pieces and are symmetrically arranged. The sampling seat includes a support portion. When the two positioning seats are close to each other and fitted together, a clamping groove for clamping the support portion is formed, wherein the diameter of the support portion is the same as the diameter of the sampling groove.

[0018] According to the demolding and sampling device for reshaping saturated soft soil triaxial specimens described in the embodiment of the first aspect of the present application, the sampling component includes a base and a motor, the base is provided with a clamping hole for positioning the sampling seat, each of the positioning seats is equipped with a motor, and a screw is provided on the output shaft of the motor, and the screw is threadedly connected to the positioning seat placed on the base.

[0019] According to an embodiment of the second aspect of the present application, a method for using a demolding and sampling device for reshaping a saturated soft soil triaxial specimen is provided, comprising the following steps:

[0020] Placing the turnover device on the second support platform so that the central axes of the turnover device and the avoidance hole are collinear;

[0021] The transfer assembly is started, and the second pressing plate is driven by the driving member to pass through the revolver and then move upward to be level with the first supporting platform, and a permeable stone and filter paper are placed on the second pressing plate;

[0022] Placing a saturator formed with a saturated soft soil sample on the first cap, with the central axes of the saturator and the avoidance hole collinear, and placing permeable stone and filter paper on top of the saturator;

[0023] Driving the driving member to move downward, so that the first pressing plate presses one end of the saturated soft soil sample and the second pressing plate supports the other end of the saturated soft soil sample, thereby transferring the saturated soft soil sample to the sample loading slot of the turnover device;

[0024] After adjusting the positions of the sample loading seat and the positioning seat, hold the permeable stones at the upper and lower ends of the turnover device, transfer the turnover device to the sample loading seat, dock the flexible connector with the sample loading seat, dock the turnover device with the positioning seat, release the restrictions of the flexible connector on the first and second molded parts, and then drive the first and second molded parts to separate through the positioning seat, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present application is further described below with reference to the accompanying drawings and embodiments;

[0027] Figure 1 This is a schematic diagram of the structure of the demoulding and sampling device for reshaping the saturated soft soil triaxial specimen in the embodiment of the present application. Figure 1 ;

[0028] Figure 2 This is a schematic structural diagram of a turnover device in an embodiment of the present application;

[0029] Figure 3 This is a schematic diagram of the structure of the demoulding and sampling device for reshaping saturated soft soil triaxial specimens in the embodiment of the present application. Figure 2 ;

[0030] Figure 4 This is a schematic diagram of the structure of the sample loading component in the embodiment of the present application. Figure 1 ;

[0031] Figure 5 This is a schematic diagram of the structure of the sample loading component in the embodiment of the present application. Figure 2 .

[0032] Figure markings: mounting frame 100, first supporting platform 110, second supporting platform 120, avoidance hole 130, driving member 140, first connecting rod 150, first pressure plate 160, second connecting rod 170, second pressure plate 180, saturator 200, turnover device 300, first molded part 310, second molded part 320, docking channel 321, first docking hole 330, base 410, motor 420, positioning seat 430, positioning member 431, second docking hole 432, screw 440, sample loading seat 450. DETAILED DESCRIPTION

[0033] This section will describe the specific embodiments of the present application in detail. The preferred embodiments of the present application are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present application, but it cannot be understood as a limitation on the scope of protection of the present application.

[0034] In the description of this application, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0035] In the description of this application, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The terms "first" and "second" are used solely to distinguish technical features and are not to be construed as indicating or implying relative importance, or as implicitly specifying the number or order of the technical features indicated.

[0036] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0037] The existing triaxial specimen loading technologies mainly include the following methods:

[0038] 1. Use a cylindrical sleeve, a rubber tube and a plastic ball. Put the rubber membrane on the sleeve, connect the rubber tube, use a plastic ball to evacuate the air between the inner wall of the sleeve and the rubber membrane, then put the demolded triaxial specimen into the sleeve and install it on the triaxial apparatus. Using a sleeve and a rubber membrane to install the triaxial specimen can indeed play a certain fixing role, but it is only limited to soils with relatively high strength. This type of soil has high strength and small deformation after demolding, and is easy to enter the inside of the sleeve. When the soil strength is relatively low and the rheology is large, after vacuum saturation, first of all, the success rate of escaping from the three-valve membrane saturator 200 is low. Secondly, after escaping, the lower end of the specimen will expand under the action of its own gravity and cannot be loaded into the sleeve, which will eventually lead to the failure of the experiment and may waste a large number of triaxial saturated specimens.

[0039] 2. Using a two-valve membrane, after the sample is installed on the triaxial apparatus, in the process of placing the back-pressure cap, in order to reduce the disturbance of the triaxial sample, a two-valve membrane is installed around the sample to restrain the deformation of the soil, and it is removed before installing the confining pressure chamber. After the sample is successfully installed on the triaxial apparatus base 410, before placing the back-pressure cap, the two-valve membrane is used to restrain the sample, which supports the sample to a certain extent. However, before installing the confining pressure chamber, the two-valve membrane needs to be removed. After removal, the supporting effect on the soil disappears. Under the combined action of the gravity of the back-pressure cap and the pressure of the axial pressure support rod of the triaxial apparatus, the saturated soft soil sample is easily damaged. After being damaged on the triaxial apparatus, the diameter and height of the sample change, and the triaxial test cannot be continued.

[0040] 3. Use a two-valve membrane with a rubber tube and a rubber mold to directly compact the sample on the triaxial instrument and saturate it with water head. Using a two-valve membrane with a rubber tube can realize the sample loading on the triaxial instrument, and then use water head saturation. This method can indeed realize the reshaping of soft soil and the loading of samples into the triaxial instrument, because the unsaturated soil has high strength and will not be affected by the gravity of the back pressure cap and the triaxial support rod. However, the sample loading operation steps on the triaxial instrument are cumbersome and complicated, and the layered compaction error is large, resulting in inaccurate test results. Compared with the sample after vacuum saturation in the saturator 200 (vacuum saturation can saturate multiple samples at a time), the water head saturation process takes a long time. If the dry density of the soil is large, the water head saturation may last for 1 to 3 days, which increases the test cycle. The cost of using the triaxial instrument is relatively high at this stage, and manual sample preparation and water head saturation will waste a lot of manpower and financial resources.

[0041] In order to solve the problems existing in the prior art, Figures 1 to 5The embodiment of the present application provides a demolding and sampling device for reshaping a saturated soft soil triaxial specimen, including a saturator 200, a turnover device 300, a demolding component, and a sampling component.

[0042] The saturator 200 is used to form saturated soft soil samples, and the turnover device 300 is used to circulate saturated soft soil. Among them, the demoulding component is used to transfer the saturated soft soil sample in the saturator 200 to the turnover device 300 without loss. The sample loading component is used to solve the problem of instability of the triaxial sample itself or instability under pressure after loading.

[0043] The revolver 300 comprises a first molded part 310, a second molded part 320, and a flexible connector. The first and second molded parts 310 and 320 are connected by the flexible connector to form a sample loading trough. The sample loading trough has the same shape and dimensions as the trough used to form saturated soft soil specimens within the saturator 200, ensuring lossless demolding and transfer during saturated soft soil experiments. After the flexible connector connects the first and second molded parts 310 and 320, a portion of the flexible connector forms the inner wall of the sample loading trough.

[0044] The demolding component includes a first support 110, a second support 120 and a transfer assembly. The central axes of the first support 110 and the second support 120 are collinear, and the distance between the first support 110 and the second support 120 is equal to the height of the revolver 300. The middle parts of the first support 110 and the second support 120 are both provided with avoidance holes 130. The first support 110 is used to support the saturator 200, and the second support 120 is used to support the revolver 300. The soft soil sample in the saturator 200 is transferred to the sample loading slot of the revolver 300 through the transfer assembly.

[0045] During demoulding, the saturator 200 containing the saturated soft soil sample is placed on the first support 110, and the turnover device 300 is placed on the second support 120, and the saturator 200 and the turnover device 300 are connected up and down. The saturated soft soil sample in the saturator 200 is transferred from the avoidance hole 130 to the sample loading slot of the turnover device 300 through the transfer assembly to ensure that the saturated soft soil sample is not damaged or deformed by its gravity and external pressure.

[0046] The sample loading component includes a sample loading seat 450 and a retractable positioning seat 430. After the flexible connector is docked with the sample loading seat 450, the turnover device 300 is docked with the positioning seat 430. After the flexible connector releases the restriction on the first molded part 310 and the second molded part 320, the positioning seat 430 drives the first molded part 310 and the second molded part 320 to separate, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat 450.

[0047] After the saturated soft soil sample is transferred to the revolver 300, the revolver 300 is transferred to the sample loading seat 450 of the sample loading component. After the flexible connector is docked with the sample loading seat 450, the positioning seat 430 is docked with the first mold part 310 or the second mold part 320. After the restriction of the flexible connector on the first mold part 310 and the second mold part 320 is released, the first mold part 310 and the second mold part 320 are driven to separate through the positioning seat 430, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat 450.

[0048] Compared with the existing technology, the demoulding component of the present application can transfer the soft soil sample after vacuum saturation from the saturator 200 to the turnover device 300, and the upper and lower platforms clamp the soil sample in the middle, thereby minimizing the disturbance of the sample; the sample loading component can ensure that after the sample is installed on the triaxial apparatus, when the back pressure cap and the support rod are installed, the soft soil sample is protected from its gravity and pressure, thereby solving the problem of the triaxial sample itself becoming unstable or becoming unstable under pressure after loading, and at the same time leaving enough space for the sample to deform under pressure, thereby improving the success rate of the triaxial test.

[0049] In some specific embodiments, Figure 2 As shown, the first molded part 310 and the second molded part 320 are combined to form a hollow cylinder. The ends of the cylinder are fixed by a flexible connector, which is then attached to the inner wall of the cylinder, thereby forming a sample loading groove. The revolver 300 is configured with a detachable first molded part 310 and second molded part 320, which facilitates demolding and sample loading, greatly improving installation and testing efficiency.

[0050] In the embodiment of the present application, the first molded part 310 and the second molded part 320 are symmetrical to each other. The provision of the flexible connector can, on the one hand, connect the first molded part 310 and the second molded part 320 into one body, and on the other hand, make the inner wall of the formed cylinder smoother and more continuous. Before demolding, vaseline needs to be applied in the sample loading groove to make the transfer of saturated soft soil smoother.

[0051] In some specific embodiments, the flexible connector is cylindrical, and the end of the flexible connector is turned outward to the end surface of the wrapped cylinder. The first part 310 and the second part 320 are connected together through the elastic deformation of the flexible connector, and the rebound force generated by the elastic deformation force of the flexible connector is effectively utilized. When the revolver 300 is transferred to the sample loading seat 450, the revolver 300 can also be positioned on the sample loading seat 450 through the flexible connector.

[0052] In some embodiments, the flexible connector is made of rubber, and a docking channel 321 is provided on the outside of the first molded part 310 or the second molded part 320. The docking channel 321 is connected to the interior of the cylinder. The air between the inner wall of the cylinder and the flexible connector is extracted through the docking channel 321 to make the flexible connector fit the inner wall of the cylinder, ensuring that the diameter of the sample loading groove formed is the same as the inner diameter of the saturator 200.

[0053] In some specific embodiments, the end faces of the first form member 310 and the second form member 320 are each provided with at least two first docking holes 330, and the positioning seat 430 is provided with second docking holes 432 that are the same in number and corresponding in position to the first docking holes 330. After the first docking holes 330 are aligned with the second docking holes 432, the first form member 310 or the second form member 320 is positioned in the positioning seat 430 by means of pins passing through the first docking holes 330 and the second docking holes 432.

[0054] Among them, a positioning member 431 with the same shape as the first molded part 310 or the second molded part 320 is provided on the positioning seat 430, and the second docking hole 432 is provided on the end face of the positioning member 431. Through the cooperation of the first docking hole 330 and the second docking hole 432 with the pin, the first molded part 310 or the second molded part 320 of the turnover device 300 can be quickly positioned on the positioning member 431, thereby improving the sample loading speed.

[0055] In some embodiments, such as Figure 1 and Figure 3 As shown, the transfer assembly includes a first pressure plate 160, a second pressure plate 180 and a driving member 140 that can be raised and lowered in a direction parallel to the central axis of the avoidance hole 130. The central axes of the first pressure plate 160, the second pressure plate 180, the first support 110 and the second support 120 are collinear. The distance between the first pressure plate 160 and the second pressure plate 180 is equal to the height of the revolver 300. The driving member 140 drives the first pressure plate 160 and the second pressure plate 180 to move synchronously, so that the saturated soft soil sample of the saturator 200 can be transferred to the sample loading slot of the revolver 300 without damage.

[0056] In the embodiment of the present application, the driving member 140 includes a first connecting rod 150 and a second connecting rod 170. The first connecting rod 150 and the second connecting rod 170 each include a horizontal section and a vertical section. The ratio of the distance between the two horizontal sections to the height of the revolver 300 is greater than 2. The vertical section is collinear with the central axis of the avoidance hole 130. The first pressure plate 160 is provided on the first connecting rod 150, and the second pressure plate 180 is provided on the second connecting rod 170. By controlling the distance between the horizontal sections and providing the vertical sections, the movement of the driving member 140 is not interfered with by the platform.

[0057] In an embodiment of the present application, the demolding component also includes a base plate, a mounting frame 100 and a guide sleeve. The mounting frame 100 and the guide sleeve are both arranged on the base plate. The mounting frame 100 is used for the installation of the first support platform 110 and the second support platform 120. The driving member 140 also includes a rod. The guide sleeve is vertically arranged, and the rod is inserted into the guide sleeve. Under the cooperation of the guide sleeve and the rod, the driving member 140 can move up and down in the vertical direction. Furthermore, the guide sleeve is also provided with a pre-tightening screw to limit the movement of the rod.

[0058] In this embodiment, two positioning seats 430 are symmetrically arranged. The sample loading seat 450 includes a support portion. The two positioning seats 430 are brought into close proximity and abutted to form a clamping groove for securing the support portion. The diameter of the support portion is the same as the diameter of the sample loading groove. During sample loading, the two positioning seats 430 are brought together, the first molded member 310 of the revolver 300 docks with one positioning seat 430, and the second molded member 320 docks with the other positioning seat 430. By driving the two positioning seats 430 away from each other, the saturated soft soil is positioned within the support portion of the sample loading seat 450.

[0059] In some specific embodiments, the sample loading component includes a base 410 and a motor 420. The base 410 is provided with a clamping hole for positioning the sample loading seat 450. Each positioning seat 430 is equipped with a motor 420. A screw 440 is provided on the output shaft of the motor 420. The screw 440 is threadedly connected to the positioning seat 430 placed on the base 410. Through the cooperation of the base 410, the screw 440 and the motor 420, the positioning seat 430 can perform linear reciprocating motion.

[0060] The present application also provides a method for using the demoulding and sampling device for reshaping a saturated soft soil triaxial specimen, comprising the following steps:

[0061] Place the turnover device 300 on the second support platform 120 so that the central axes of the turnover device 300 and the avoidance hole 130 are collinear;

[0062] Start the transfer assembly, and drive the second pressing plate 180 through the revolver 300 through the driving member 140 and move it upward until it is flush with the first support platform 110, and place the permeable stone and filter paper on the second pressing plate 180;

[0063] Place the saturator 200 with the saturated soft soil sample on the first foundation 110, and make the central axes of the saturator 200 and the avoidance hole 130 collinear, and place permeable stone and filter paper on the top of the saturator 200;

[0064] The driving member 140 is driven to move downward, so that the first pressing plate 160 presses one end of the saturated soft soil sample, and the second pressing plate 180 supports the other end of the saturated soft soil sample, thereby transferring the saturated soft soil sample to the sample loading slot of the turnover device 300;

[0065] After adjusting the positions of the sample loading seat 450 and the positioning seat 430, hold the permeable stones at the upper and lower ends of the turnover device 300, transfer the turnover device 300 to the sample loading seat 450, dock the flexible connector with the sample loading seat 450, dock the turnover device 300 with the positioning seat 430, release the restriction of the flexible connector on the first molded part 310 and the second molded part 320, and then drive the first molded part 310 and the second molded part 320 to separate through the positioning seat 430, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat 450.

[0066] Before conducting the triaxial test, the vacuum-saturated soft soil sample must be removed from the saturator 200. The demolding device in this application can minimize disturbance of the soft soil sample, ensuring the success of the experiment. During demolding, the first molded part 310 and the second molded part 320 must first be connected together using a flexible connector. A rubber tube is inserted into the docking channel 321. A rubber ball is used to evacuate the air between the cylinder and the flexible connector, so that the flexible connector is tightly attached to the inner wall of the cylinder to form a sample loading groove. After applying vaseline to the sample loading groove, it is placed on the second support 120, aligning the revolver 300 with the avoidance hole 130. Next, raise the second pressing plate 180 to its highest point and sequentially place a permeable stone and filter paper on it. Next, place the saturator 200 on the first support 110 and align it with the avoidance hole 130, ensuring that the centers of the revolver 300, the avoidance hole 130, and the saturator 200 are aligned. Filter paper and permeable stone are also placed above the saturated soft soil sample in the saturator 200. After completing the above steps, press the first pressing plate 160 downward to contact the permeable stone above the saturator 200. At this point, manually press the compression driver 140, transferring the saturated soft soil sample in the saturator 200 to the revolver 300.

[0067] After the saturated soft soil sample is taken out of the saturator 200 and placed in the revolver 300, hold the permeable stone by hand and transfer the saturated soft soil sample to the sample loading component. First, put the flexible connector of the saturator 200 onto the sample loading seat 450, then fix it with a rubber ring, and then install the positioning seat 430. Place the positioning seat 430 on both sides of the sample loading seat 450 so that the clamping groove clamps the support part of the sample loading seat 450. Then place the removed saturated soft soil sample together with the revolver 300 into the sample loading seat 450, insert the pin into the docking hole, and connect the revolver 300 to the positioning seat 430. After completing the above steps, a back pressure cap can be installed on the saturated soft soil sample. Since the sample loading seat 450 has a lateral support force on the sample, the sample will not be damaged. After the installation is completed, it is installed in the confining pressure chamber, and the sample loading device and the sample are left in the confining pressure chamber. After the confining pressure chamber is filled with water, a certain equivalent confining pressure is applied. The sample is slightly deformed by the confining pressure. At this time, the remote control motor 420 rotates the screw 440, allowing the left and right positioning seats 430 to move backward, leaving enough space for the shear deformation of the sample, and finally completing the triaxial test.

[0068] Existing sleeves are only suitable for strong soils that are not affected by their own gravity in natural environments. Soft soil specimens, whether remolded or saturated, will deform under natural energy conditions, typically increasing in diameter at the bottom. This prevents them from fitting into the sleeve, leading to experimental failure.

[0069] In addition, the existing two-piece mold does play a certain protective role when installing the back-pressure cap. However, before installing the confining pressure chamber, the two-piece mold needs to be removed. Under the action of the gravity of the two-piece mold and the gravity of the soft soil sample itself, the soft soil sample will be deformed or even destroyed, resulting in test failure.

[0070] Furthermore, due to the high rheological properties of soft soil samples after saturation, many researchers choose to prepare samples on a triaxial machine using hydraulic head saturation. This method is complex to operate, has a long experimental cycle, and is prone to uneven sample loading, ultimately leading to test failure. The present invention achieves successful demolding of soft soil samples after vacuum saturation, improving experimental efficiency and reducing waste of manpower, financial resources, and material resources.

[0071] This application is mainly aimed at the demoulding and loading problems of soft soil samples with large rheological properties after vacuum saturation. Generally, soft soil samples are loaded in layers on a triaxial apparatus and then saturated with water head, which is complicated to operate and has a long test cycle. Vacuum saturation is fast and can saturate a large number of samples at the same time, greatly shortening the test cycle and reducing manpower waste. However, it is difficult to remove the sample after the vacuum tube is saturated. This application ensures the successful demoulding of the triaxial sample.

[0072] The sample after vacuum saturation has large rheological properties and is easily deformed under the action of its own gravity after being removed from the saturator 200, making it difficult to load into the revolver 300. This application connects the saturator 200 and the revolver 300 up and down, so that the soft soil sample can directly enter the revolver 300 after demolding, avoiding damage to the sample.

[0073] After the sample is removed from the saturator 200, it is subjected to greater disturbance when it is installed on the triaxial apparatus. Under the combined action of its own gravity, the back pressure cap, and the support rod, the sample will develop into an irregular structure that is narrow at the top and wide at the bottom, and its height and diameter will change. In order to obtain the deviatoric stress-strain curve, the triaxial test requires strict control of the sample size. In this application, the mold-mounting component is connected to the revolver 300 in the demolding device, so that the revolver 300 is left in the confining pressure chamber, and it always protects the triaxial sample before the confining pressure is applied. After the confining pressure is applied, the revolver 300 is disengaged from the triaxial sample by moving the positioning seat 430, leaving it with deformation space, thereby improving the success rate of the test.

[0074] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A demoulding and sampling device for reshaping saturated soft soil triaxial specimens, characterized by: include Saturator, used to form saturated soft soil specimens; The turnover device includes a first molded part, a second molded part, and a flexible connector, wherein the first molded part and the second molded part are connected by the flexible connector to form a sample loading slot; A demolding component includes a first support, a second support, and a transfer assembly, wherein the central axes of the first support and the second support are collinear, and the distance between the first support and the second support is equal to the height of the turnover device, wherein the middle portions of the first support and the second support are each provided with an avoidance hole, the first support is used to support the saturator, and the second support is used to support the turnover device, and the soft soil sample in the saturator is transferred to the sample loading slot of the turnover device via the transfer assembly; The sample loading component includes a sample loading seat and a retractable positioning seat. After the flexible connector is docked with the sample loading seat, the turnover device is docked with the positioning seat. After the restriction of the flexible connector on the first and second molded parts is released, the first and second molded parts are driven to separate through the positioning seat, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat.

2. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 1 is characterized in that: The first molded part and the second molded part are folded together to form a hollow cylinder. The ends of the cylinder are fixed by the flexible connector so that the flexible connector fits the inner wall of the cylinder, thereby forming the sample loading groove.

3. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 2 is characterized in that: The flexible connector is cylindrical, and the end of the flexible connector is turned outward to wrap the end surface of the cylinder. The first part and the second part are connected together through the elastic deformation of the flexible connector.

4. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 3 is characterized in that: The flexible connector is made of rubber, and a docking channel is provided on the outside of the first or second shaped member. The docking channel is connected to the interior of the cylinder. The air between the inner wall of the cylinder and the flexible connector is extracted through the docking channel to make the flexible connector fit the inner wall of the cylinder.

5. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 1 is characterized in that: The end faces of the first and second molded parts are each provided with at least two first docking holes, and the positioning seat is provided with second docking holes that are the same in number and corresponding in position to the first docking holes. After the first docking holes are aligned with the second docking holes, the first molded part or the second molded part is positioned on the positioning seat by means of pins passing through the first and second docking holes.

6. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to any one of claims 1 to 5, characterized in that: The transfer assembly includes a first pressure plate, a second pressure plate and a driving member that can be raised and lowered in a direction parallel to the central axis of the avoidance hole. The central axes of the first pressure plate, the second pressure plate, the first support platform and the second support platform are collinear. The distance between the first pressure plate and the second pressure plate is equal to the height of the turnover device. The first pressure plate and the second pressure plate are driven to move synchronously by the driving member.

7. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 6, characterized in that: The driving member includes a first connecting rod and a second connecting rod, and the first connecting rod and the second connecting rod each include a horizontal section and a vertical section. The ratio of the distance between the two horizontal sections to the height of the revolver is greater than 2, and the vertical section is collinear with the central axis of the avoidance hole. The first pressure plate is arranged on the first connecting rod, and the second pressure plate is arranged on the second connecting rod.

8. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 1 is characterized in that: The positioning seats are provided in two pieces and are symmetrically arranged. The sample loading seat includes a supporting portion. When the two positioning seats are close to each other and fitted together, a clamping groove for clamping the supporting portion is formed. The diameter of the supporting portion is the same as that of the sample loading groove.

9. The demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to claim 8, characterized in that: The sample loading component includes a base and a motor. The base is provided with a clamping hole for positioning the sample loading seat. Each positioning seat is equipped with a motor. A screw is provided on the output shaft of the motor. The screw is threadedly connected to the positioning seat placed on the base.

10. A method for using the demoulding and sampling device for reshaped saturated soft soil triaxial specimens according to any one of claims 6 to 9, characterized in that: The steps include: Placing the turnover device on the second support platform so that the central axes of the turnover device and the avoidance hole are collinear; The transfer assembly is started, and the second pressing plate is driven by the driving member to pass through the revolver and then move upward to be level with the first supporting platform, and a permeable stone and filter paper are placed on the second pressing plate; Placing a saturator formed with a saturated soft soil sample on the first cap, with the central axes of the saturator and the avoidance hole collinear, and placing permeable stone and filter paper on top of the saturator; Driving the driving member to move downward, so that the first pressing plate presses one end of the saturated soft soil sample and the second pressing plate supports the other end of the saturated soft soil sample, thereby transferring the saturated soft soil sample to the sample loading slot of the turnover device; After adjusting the positions of the sample loading seat and the positioning seat, hold the permeable stones at the upper and lower ends of the turnover device, transfer the turnover device to the sample loading seat, dock the flexible connector with the sample loading seat, dock the turnover device with the positioning seat, release the restrictions of the flexible connector on the first and second molded parts, and then drive the first and second molded parts to separate through the positioning seat, so that the saturated soft soil sample wrapped by the flexible connector is positioned on the sample loading seat.

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