A high-pressure non-drained compression consolidation test device

Abstract

This utility model discloses a high-pressure undrained compression consolidation test device, relating to the field of geotechnical testing equipment in geotechnical engineering. It includes a test barrel, a top cover, and a bottom cover. Both the top and bottom ends of the test barrel are open. The top cover is sealed to the top end of the test barrel, and the bottom cover is sealed to the bottom end of the test barrel. Both the top and bottom covers are equipped with sealing structures to ensure a undrained environment within the test barrel during the test. This utility model solves the problem of insufficient sealing performance in existing compression consolidation apparatuses under high pressure, which prevents them from achieving completely undrained conditions. By setting up sealing structures, it ensures that the test barrel can be completely sealed and prevent drainage under high pressure. This device is simple to modify, has good applicability, and can be widely used for simulating various geotechnical tests under completely undrained conditions, including undrained state simulation tests of various fine-grained soils and gravelly soil core materials, making it easy to promote.

Description

Technical Field

[0001] This utility model relates to the technical field of geotechnical testing equipment for geotechnical engineering, and specifically to a high-pressure undrained compression consolidation test device. Background Technology

[0002] Currently, in studies of pore water pressure in core wall materials of high earth-rock dams, conventional compression consolidation apparatuses are commonly used for indoor model tests. These apparatuses typically cannot achieve completely undrained conditions, and the drainage path is relatively short, resulting in pore water pressure measurements during tests that are significantly lower than actual engineering conditions. This error primarily stems from the apparatus structure's inability to realistically simulate the undrained environmental conditions on-site, especially under high-pressure conditions.

[0003] Therefore, there is an urgent need for an improved compression consolidation test apparatus that can achieve a closed, non-drained test under high pressure to improve test accuracy and the accuracy of test simulation. Utility Model Content

[0004] The technical problem this invention aims to solve is that existing compression consolidation apparatuses lack sufficient sealing performance under high pressure, failing to achieve a completely non-draining condition. The objective is to provide a high-pressure, non-draining compression consolidation test device for accurately simulating the formation and dissipation of pore water pressure in the core wall material of a dam.

[0005] This utility model is achieved through the following technical solution: A high-pressure non-drained compression consolidation test device includes a test barrel, a top cover, and a bottom cover. The top and bottom ends of the test barrel are open. The top cover is sealed to the top end of the test barrel, and the bottom cover is sealed to the bottom end of the test barrel. Both the top and bottom covers are provided with sealing structures to create a non-drained environment in the test barrel during the test.

[0006] As one of the preferred technical solutions, the sealing structure includes an annular closed groove provided on the outer edge of the top cover and the bottom cover.

[0007] As one of the preferred technical solutions, the top cover and the bottom cover are each provided with two annular closed grooves, and the two annular closed grooves form a double annular closed groove.

[0008] As a preferred technical solution, a sealing ring is embedded in each of the annular closed grooves.

[0009] As one of the preferred technical solutions, the sealing ring is made of high-pressure resistant rubber.

[0010] As one of the preferred technical solutions, the top and bottom of the test barrel extend outward to form an annular inclined portion, which is sealed to the top or bottom cover.

[0011] As one of the preferred technical solutions, the depth of the annular inclined portion is 50mm.

[0012] As one of the preferred technical solutions, the inclination angle of the cross-section of the annular inclined portion is 5°.

[0013] This application verifies through comparative experiments that a gently sloping annular section (0°) is prone to micro-leakage, while a steeply sloping annular section (10°) poses difficulties in press-fitting and risks damaging the sealing ring. The sealing effect is best when the inclination angle of the annular section cross-section is 5°.

[0014] As one of the preferred technical solutions, the test barrel is equipped with a sensor for measuring pore water pressure, and the test barrel is also equipped with a signal lead channel with high-pressure sealing protection.

[0015] As one of the preferred technical solutions, the test barrel body, bottom cover, and top cover are all made of steel.

[0016] Compared with the prior art, this utility model has the following advantages and beneficial effects: 1. By setting up a sealing structure, it is ensured that the test barrel can be completely sealed and not drain under high pressure.

[0017] 2. This device is simple to modify and has good applicability. It can be widely used to simulate various geotechnical tests under completely undrained conditions, including undrained state test simulations of various fine-grained soils and gravelly soil core wall materials, making it easy to promote. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of the test barrel of this utility model; Figure 3 This is a schematic diagram of the internal structure of the test barrel of this utility model.

[0019] The attached diagram shows the markings and corresponding component names: 1-Test barrel body, 2-Top cover, 3-Bottom cover, 4-Annular closed groove, 5-Sealing ring, 6-Annular inclined part, 7-Sensor, 8-Signal lead channel. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model. Example 1

[0021] Indoor model tests were conducted using a conventional compression consolidation apparatus. This type of apparatus typically cannot achieve completely undrained conditions, and the drainage path is relatively short, resulting in pore water pressure readings during the tests being significantly lower than those under actual engineering conditions. This error primarily stems from the apparatus's inability to realistically simulate the undrained environment conditions in the field, especially under high-pressure conditions.

[0022] Based on the above problems, this embodiment provides a high-pressure non-drained compression consolidation test apparatus, such as... Figure 1 As shown, the test chamber includes a test barrel 1, a top cover 2, and a bottom cover 3. In this embodiment, the test barrel 1 is made of metal steel with an inner diameter of 498 mm, a wall thickness of 20 mm, and a height of 600 mm. Both the top and bottom ends of the test barrel 1 are open. The top cover 2 is sealed to the top end of the test barrel 1, and the bottom cover 3 is sealed to the bottom end of the test barrel 1. Specifically, the top cover 2 and the bottom cover 3 are made of high-strength steel plate with a thickness of 30 mm.

[0023] During the assembly process, the top cover 2 and the bottom cover 3 are slowly pressed into the test barrel 1 by the hydraulic loading system. The sealing structure set in the top cover 2 and the bottom cover 3 is tightly fitted to the test barrel 1 to ensure that the test barrel 1 forms a non-drainage environment during the test. Example 2

[0024] The sealing structure in this embodiment includes annular closed grooves 4 disposed on the outer edges of the top cover 2 and the bottom cover 3. The grooves are 6 mm deep and 8 mm wide. It is understood that the annular closed grooves 4 are located at the contact points with the test barrel 1 for sealing cooperation with the test barrel 1. To further enhance the sealing effect, two annular closed grooves 4 are provided on both the top cover 2 and the bottom cover 3 in this embodiment, forming a double annular closed groove.

[0025] Each annular closed groove 4 is fitted with a sealing ring 5, and the sidewalls of the closed groove restrict the axial movement of the sealing ring 5, preventing it from detaching under vibration or high pressure. It can be seen that when a double-ringed closed groove is used, the sealing ring 5 is also a double-sealed sealing ring. Furthermore, the sealing ring 5 effectively fits against the inner wall of the barrel, improving sealing performance. It can also be seen that the double-sealed ring consists of a main sealing lip and an auxiliary sealing lip, forming two independent sealing barriers. Even if the main sealing lip fails due to wear, aging, or accidental damage, the auxiliary sealing lip can continue to function, preventing media leakage and significantly reducing the risk of system failure. The auxiliary sealing lip can share the pressure of the main sealing lip, reducing the risk of rubber material being squeezed into the gap under high pressure and extending the seal life.

[0026] Furthermore, the sealing ring 5 is made of high-pressure resistant rubber with a cross-sectional diameter of 7mm, and has a certain pre-tightening amount after being embedded in the groove. During installation, a special hydraulic loading device is used to slowly press the top cover 2 and the bottom cover 3 into the barrel along the axial direction, so that the sealing ring 5 gradually contacts, is pressed into, and forms a sealing interface with the smooth surface.

[0027] like Figure 2 As shown, the top and bottom of the test barrel 1 extend outward to form annular inclined portions 6, which are sealed to the top cover 2 or bottom cover 3. Specifically, the depth of the annular inclined portion 6 is 50mm, and the inclination angle of the cross-section is 5°. The shape of the annular inclined portion 6 is similar to a frustum of a cone with openings at both ends. The effect is that under internal pressure, the annular inclined portion 6 generates a radial force, further compressing the sealing ring 5, creating a self-reinforcing effect of "the higher the pressure, the tighter the seal," suitable for high-pressure or fluctuating pressure scenarios. Furthermore, the cooperation between the annular inclined portion 6 and the top cover 2 / bottom cover 3 forms a triangular support structure, improving overall bending stiffness, reducing barrel deformation under high pressure or vibration, and ensuring long-term stable contact of the sealing surface.

[0028] Furthermore, to optimize the bevel machining parameters and sealing structure, this embodiment conducted a comparative experiment to test the sealing effect of different annular inclined sections with six inclination angles (0°, 5°, and 10°) and five types of sealing rings (single-channel and double-channel). In this experiment, all samples used test barrels of the same size, i.e., an inner diameter of 498 mm; each group of tests was loaded to 5 MPa and subjected to static pressure holding for 10 hours; the evaluation criteria were whether water seeped from the top of the sample and the stability of the pore pressure. The sealing condition of each group was observed.

[0029] The final experimental results showed that a gentler annular slope (0°) was prone to micro-leakage, while a steeper slope (10°) posed a risk of difficulty in press-fitting and damage to the sealing ring 5. A 5° inclination angle of the annular slope 6 cross-section resulted in the best sealing effect. Furthermore, the sealing effect of a double-ring seal was superior to that of a single-ring seal.

[0030] It is known that the dual structure of the 5° annular inclined section 6 combined with the double closed high-pressure sealing ring performs optimally in terms of balancing assembly efficiency and sealing reliability.

[0031] Example 3: Integrated Application of Signal Extraction and High Voltage Protection System Furthermore, such as Figure 3 As shown, the test tank 1 is equipped with a sensor 7 for measuring pore water pressure, and also has a signal lead channel 8. Specifically, to ensure the stable operation of the pore water sensor and the soil pressure sensor under high pressure, two pre-embedded test holes are opened on the inner side wall of the test tank 1 in this embodiment. Both test holes are threaded holes. In this process, the threaded holes are connected to the signal lead channel 8. In this embodiment, the signal lead channel 8 is a dedicated high-voltage cable lead channel. The dedicated high-voltage cable lead channel adopts a double structure of stainless steel protective pipe combined with conductive rubber sleeve. Then, the sensor 7 (including the pore water sensor and the soil pressure sensor) is installed at one end of the dedicated high-voltage cable lead channel. The high-voltage watertight cable connected to the sensor 7 leads the signal out from the dedicated high-voltage cable lead channel, realizing full-process monitoring.

[0032] In addition, all signal lines are shielded and connected to an external data acquisition system; the cable interfaces remain free from leakage, water ingress, and signal attenuation in a high-voltage testing environment.

[0033] Tests show that the system can withstand continuous 5MPa pressure loading for more than 12 hours, and sensor 7 readings are accurate and without abnormalities, meeting the requirements for long-term testing. The test setup has been verified to have no pore water leakage under loading conditions below 5MPa, effectively simulating the non-drained behavior of a high dam core wall under actual stress paths.

[0034] The high-pressure undrained compression consolidation test apparatus of this application was used. Gravelly soil with a moisture content of 8% was used as the test sample. An initial pressure of 0.5 MPa was applied, gradually increasing to 5 MPa. Pressure was monitored during the test using a pore water pressure sensor located in the middle of the sample. During the final 1-hour pressure holding period at each stage, no water seepage or leakage occurred in the test chamber 1, and the sensor 7 reading remained stable, thus verifying the excellent sealing performance and test reliability of the apparatus.

[0035] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A high-pressure undrained compression consolidation test apparatus, characterized in that, The test chamber includes a test barrel, a top cover, and a bottom cover. The top and bottom of the test barrel are open. The top cover is sealed to the top of the test barrel, and the bottom cover is sealed to the bottom of the test barrel. Both the top and bottom covers are equipped with sealing structures to create a non-draining environment in the test barrel during the test.

2. The high-pressure undrained compression consolidation test apparatus according to claim 1, characterized in that, The sealing structure includes an annular closed groove provided on the outer edge of the top cover and the bottom cover.

3. The high-pressure undrained compression consolidation test apparatus according to claim 2, characterized in that, Both the top cover and the bottom cover have two annular closed grooves, which together form a double annular closed groove.

4. The high-pressure non-drained compression consolidation test apparatus according to claim 2 or 3, characterized in that, Each of the aforementioned annular closed grooves is fitted with a sealing ring.

5. The high-pressure undrained compression consolidation test apparatus according to claim 4, characterized in that, The sealing ring is made of high-pressure resistant rubber.

6. The high-pressure undrained compression consolidation test apparatus according to claim 1, characterized in that, The top and bottom of the test barrel extend outward to form an annular inclined portion, which is sealed to the top or bottom cover.

7. The high-pressure undrained compression consolidation test apparatus according to claim 6, characterized in that, The depth of the annular inclined portion is 50 mm.

8. The high-pressure non-drained compression consolidation test apparatus according to claim 6, characterized in that, The inclination angle of the cross-section of the annular inclined portion is 5°.

9. The high-pressure undrained compression consolidation test apparatus according to claim 1, characterized in that, The test barrel is equipped with a sensor for measuring pore water pressure, and the test barrel is also equipped with a signal lead channel with high-pressure sealing protection.

10. The high-pressure undrained compression consolidation test apparatus according to claim 1, characterized in that, The test barrel body, bottom cover, and top cover are all made of steel.

Images