Marine facies soft soil triaxial test device

Abstract

The invention relates to the technical field of geotechnical test instruments, and discloses a marine soft soil triaxial test device which comprises a pressure chamber, an air extraction assembly and a water supply mechanism, one end of the air extraction assembly is connected with the top end of the pressure chamber, and the air extraction assembly comprises a vacuum air extraction pump used for extracting air in the pressure chamber; a confining pressure control pipe is arranged at the bottom of the pressure chamber, the water supply mechanism is detachably connected with the confining pressure control pipe, and water can be injected into the pressure chamber based on the height difference between the water supply mechanism and the pressure chamber and / or vacuum pressure formed in the pressure chamber. And a control valve for controlling the on-off state of the confining pressure control pipe is arranged on the confining pressure control pipe. No residual gas exists in the pressure chamber of the marine facies soft soil triaxial test device, the saturation rate of a marine facies soft soil sample in the pressure chamber is increased, disturbance damage to the marine facies soft soil sample is avoided, and the accuracy of test data is improved.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical testing instruments, in particular to a marine soft soil triaxial testing device. Background Art

[0002] Marine soft soil is usually easy to break, has a high porosity and high compressibility. Its engineering properties are special and have characteristics that are quite different from those of conventional terrestrial soil. In conventional triaxial tests of marine soft soil, during the water injection stage of the pressure chamber, the large impact force generated by the triaxial instrument water pump will cause significant disturbance and damage to the marine soft soil sample, resulting in deviations in the test data. At the same time, the residual air in the pressure chamber causes the marine soft soil sample to reach saturation more slowly, affecting the progress of the test.

[0003] In summary, how to solve the influence of water injection method of pressure chamber and residual air on marine soft soil specimens in triaxial test has become an urgent problem to be solved by technicians in this field. Summary of the invention

[0004] The purpose of the present invention is to overcome the above problems existing in the prior art and to provide a marine soft soil triaxial test device.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a triaxial test device for marine soft soil, which includes a pressure chamber, an air extraction component and a water supply mechanism. One end of the air extraction component is connected to the top of the pressure chamber, and the air extraction component includes a vacuum pump for extracting air in the pressure chamber. A confining pressure control pipe is provided at the bottom of the pressure chamber. The water supply mechanism is detachably connected to the confining pressure control pipe and can inject water into the pressure chamber based on the height difference between the water supply mechanism and the pressure chamber and / or the vacuum pressure formed in the pressure chamber. A control valve for controlling the on-off state of the confining pressure control pipe is provided on the confining pressure control pipe.

[0006] Preferably, the water supply mechanism comprises a water storage tank and a soft water pipe, one end of the soft water pipe extends into the bottom of the water storage tank through the water outlet at the top of the water storage tank, and the other end of the soft water pipe is connected to the confining pressure control pipe;

[0007] The water supply mechanism also includes a support structure with adjustable support height, and the water tank is supported on the support structure so that the liquid level of the water tank can be changed by changing the support height of the support structure.

[0008] Preferably, a sealing ring is provided in the water outlet for sealing the gap between the soft water pipe and the water tank at the position where the soft water pipe passes through the water outlet, and an air valve is provided on the top of the water tank for controlling the connection between the water tank and the outside world.

[0009] Preferably, a clamping seat protruding outward is formed on the top periphery of the water storage tank, and when the water storage tank is inserted into the supporting structure from the top of the supporting structure, the clamping seat is supported on the top of the supporting structure.

[0010] Preferably, the marine soft soil triaxial test device further comprises a platform, and the supporting structure comprises a plurality of square brackets stacked in a direction perpendicular to the platform;

[0011] The support structure also includes a plurality of fixing members, which are used to detachably fix and connect the upper and lower layers of square brackets, so as to reduce or increase the height difference between the bottom surface of the water tank and the liquid level of the pressure chamber by changing the number of layers of the stacked square brackets.

[0012] Preferably, the fixing member includes a bolt and a nut, and when the screw rod of the bolt passes through the connection between the upper and lower layers of the square brackets from above or below, the nut is screwed in from the tail end of the screw rod.

[0013] Preferably, a first support plate and a second support plate are sequentially arranged along the vertical direction of the square bracket, and a through hole matching the external shape of the water tank is provided at the center position of the first support plate and the second support plate, and the through hole is used for inserting the water tank, and the square bracket includes a plurality of pillars, which are supported between the first support plate and the second support plate.

[0014] Preferably, the edges of the first support plate and the second support plate extend away from the through hole to increase the support area of ​​the first support plate and the second support plate, and the edges of the first support plate and the second support plate are provided with a plurality of fixing holes for the fixing members to pass through.

[0015] Preferably, the vacuum assembly also includes a vacuum pipe and an air pipe. The air pipe is arranged at the top of the pressure chamber for supplying air circulation in the pressure chamber. One end of the vacuum pipe is detachably connected to the air pipe, and the other end is connected to the vacuum vacuum pump. The pressure chamber also includes an air cover. When vacuum is reached in the pressure chamber, the vacuum pipe is disconnected from the air pipe and the air cover is connected to the air pipe to prevent outside air from entering the pressure chamber through the air pipe.

[0016] Preferably, the air pipe and the air extraction pipe are connected by threads, and a sealing rubber ring is provided in the air pipe to seal the connection between the air extraction pipe and the air pipe.

[0017] Through the above technical scheme, the vacuum pump in the marine soft soil triaxial test device provided by the present invention extracts the air in the pressure chamber, and after the pressure chamber reaches a vacuum state, the water supply mechanism of the device starts to supply water from the bottom of the pressure chamber, and the water injection method of the water supply mechanism generates a much smaller impact force than the impact force generated by the triaxial instrument water pump during water injection. Therefore, there will be no residual gas in the pressure chamber, which accelerates the saturation rate of the marine soft soil sample in the pressure chamber, avoids disturbance and damage to the marine soft soil sample, and improves the accuracy of the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the marine soft soil triaxial test device of the present invention.

[0019] Description of Reference Numerals

[0020] 1. Pressurizing machine; 2. Pressure chamber; 201. Confining pressure control pipe; 202. Back pressure control pipe; 203. Control valve; 3. Platform; 4. Water storage tank; 401. Water pipe; 402. Sealing ring; 403. Holder; 5. Support structure; 501. Square bracket; 502. First support plate; 503. Second support plate; 504. Pillar; 505. Bolt; 506. Nut; 6. Vacuum pump; 601. Exhaust pipe; 602. Air pipe. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0022] The present invention provides a triaxial test device for marine soft soil, such as Figure 1 As shown, the marine soft soil triaxial test includes a pressure chamber 2, an air extraction component and a water supply mechanism, one end of the air extraction component is connected to the top of the pressure chamber 2, and the air extraction component includes a vacuum air pump 6 for extracting the air in the pressure chamber 2, a confining pressure control pipe 201 is provided at the bottom of the pressure chamber 2, the water supply mechanism is detachably connected to the confining pressure control pipe 201, and can inject water into the pressure chamber 2 by giving the height difference between the water supply mechanism and the pressure chamber 2 and / or the vacuum pressure formed in the pressure chamber 2, and a control valve 203 for controlling its on-off state is provided on the confining pressure control pipe 201.

[0023] Through the above technical solution, the vacuum pump 6 in the marine soft soil triaxial test device provided by the present invention extracts the air in the pressure chamber 2, and after the pressure chamber 2 reaches a vacuum state, the water supply mechanism of the device starts to supply water from the bottom of the pressure chamber 2, and the water injection method of the water supply mechanism generates a much smaller impact force than the impact force generated by the triaxial instrument water pump during water injection. Therefore, there will be no residual gas in the pressure chamber 2, which accelerates the saturation rate of the marine soft soil sample in the pressure chamber 2, while avoiding disturbance and damage to the marine soft soil sample, and improving the accuracy of the test data.

[0024] The water supply mechanism of the present invention may have any suitable structure, for example Figure 1 In the illustrated embodiment, the water supply mechanism may include a water tank 4 and a soft water pipe 401, one end of the soft water pipe 401 extends into the bottom of the water tank 4 through a water outlet at the top of the water tank 4, and the other end of the soft water pipe 401 is connected to the confining pressure control pipe 201. Under the action of vacuum suction of the pressure chamber 2, the water in the water tank 4 flows into the pressure chamber 2 from the bottom of the pressure chamber 2 through the soft water pipe 401 and the confining pressure control pipe 201.

[0025] Of course, in some other embodiments, a water outlet pipe 401 may be provided at the top of the water tank 4, the tail end of the water outlet pipe 401 extends into the bottom of the water tank 4, and the soft water pipe 401 is connected to the top end of the water outlet pipe 401.

[0026] In the present invention, if Figure 1 As shown, the water supply mechanism may further include a support structure 5 with an adjustable support height, and the water tank 4 is supported on the support structure 5 so that the liquid level of the water tank 4 can be changed by changing the support height of the support structure 5 .

[0027] In the present invention, after the air in the pressure chamber 2 is evacuated, the water tank 4 begins to inject water into the pressure chamber 2 through the soft water pipe 401. At this time, the support structure 5 is used to raise the height of the water tank 4 above the pressure chamber 2 to form a height difference between the water tank 4 and the pressure chamber 2, thereby accelerating the water in the water tank 4 to enter the pressure chamber 2; after the test, the support structure 5 is dismantled to lower the top of the water tank 4 below the confining pressure control port of the pressure chamber 2, so that the water in the pressure chamber 2 can completely flow back to the water tank 4.

[0028] In some embodiments, a sealing ring 402 may be provided at the water outlet to seal the gap between the soft water pipe 401 and the water storage tank 4 at the position where the soft water pipe 401 passes through the water outlet.

[0029] In some embodiments, an air valve can be set on the top of the water tank 4. When the pressure chamber 2 starts to suck the water in the water tank 4, the air valve on the water tank 4 is opened to connect the water tank 4 with the outside world to avoid the formation of a vacuum area on the top of the water tank 4, which causes the water in the water tank 4 to fail to fill the entire pressure chamber 2. At the same time, the flow rate of the water in the water tank 4 into the pressure chamber 2 can be adjusted by controlling the flow area of ​​the air valve.

[0030] In some embodiments, the top periphery of the water tank 4 may be formed with an outwardly protruding socket 403. When the top of the support structure 5 of the water tank 4 is inserted into the support structure 5, the socket 403 supports the top of the structure. Of course, in some other embodiments, the support method between the water tank 4 and the support structure 5 may also be other appropriate methods, which will not be elaborated in this article.

[0031] In the present invention, the marine soft soil triaxial test device may further include a pressure machine 1 and a platform 3 , and the pressure machine 1 , the pressure chamber 2 , the water supply mechanism and the air extraction assembly may all be arranged on the platform 3 .

[0032] The support structure 5 of the present invention may have any suitable structure, for example Figure 1In the illustrated embodiment, the support structure 5 may include a plurality of square brackets 501 stacked in a direction perpendicular to the platform 3. At the same time, the support structure 5 may also include a plurality of fixing members for detachably fixing and connecting the upper and lower layers of the square brackets 501, so that the height difference between the bottom surface of the water storage tank 4 and the liquid level of the pressure chamber 2 can be reduced or increased by changing the number of layers of the stacked square brackets 501.

[0033] In the present invention, if Figure 1 As shown, the fixing member may include a bolt 505 and a nut 506. When the screw of the bolt 505 passes through the connection between the upper and lower layers of the square brackets 501 from above or below, the nut 506 is screwed in from the tail end of the screw. Of course, in some other embodiments, the fixing method between the upper and lower layers of the square brackets 501 may also be a snap-fit ​​fit, which will not be described in detail herein.

[0034] The square bracket 501 of the present invention may have any suitable structure, such as Figure 1 As shown, a first supporting plate and a second supporting plate 503 may be sequentially arranged along the vertical direction of the square bracket 501, and through holes matching the external shape of the water tank 4 may be arranged at the center positions of the first supporting plate 502 and the second supporting plate 503 for inserting the water tank 4.

[0035] The square bracket 501 may also include multiple pillars 504, which are arranged on the first support plate 502 and the second support plate 503 to provide support force to the square bracket 501, and each pillar 504 may be smaller than the height of the water tank 4 to reduce the height and weight of the single-layer square bracket 501 to facilitate the test operator to carry, disassemble and assemble.

[0036] Of course, in some other embodiments, the height of the support column 504 may be greater than the height of the water tank 4 . It is worth noting that in this case, no through hole may be provided on the second support plate 503 .

[0037] In some embodiments, Figure 1 As shown, the edges of the first support plate 502 and the second support plate 503 are extended away from the through hole to increase the support area of ​​the first support plate 502 and the second support plate 503 and improve the stability of the entire stacked square bracket 501.

[0038] Fixing holes may be provided at the edges of the first support plate 502 and the second support plate 503. Figure 1 As shown, the fixing members respectively penetrate the fixing holes on the second support plate 503 of the upper layer of square brackets 501 and the fixing holes on the first support plate 502 of the lower layer of square brackets 501, thereby detachably fixing and connecting the upper and lower layers of square brackets 501.

[0039] The air extraction assembly in the present invention may have any other appropriate structure, such as Figure 1 In the illustrated embodiment, the vacuum assembly may further include a vacuum pipe 601 and an air pipe 602 . The air pipe 602 may be disposed at the top of the pressure chamber 2 . One end of the vacuum pipe 601 is detachably connected to the air pipe 602 , and the other end is connected to the vacuum pump 6 .

[0040] During the vacuuming process, the air in the pressure chamber 2 flows into the vacuum pipe 601 through the air pipe 602 and finally enters the vacuum pump 6.

[0041] In some embodiments, the pressure chamber 2 may further include an air cover. When the pressure chamber 2 reaches a vacuum state, the exhaust pipe 601 needs to be removed from the air pipe 602, and the air pipe 602 needs to be connected to the air pipe 602 to prevent external air from entering the pressure chamber 2 through the air pipe 602.

[0042] Of course, in some other embodiments, a control valve 203 may be provided in the air pipe 602 to control the on / off state of the air pipe 602 .

[0043] In the present invention, the air pipe 602 and the air extraction pipe 601 may be connected by threads and a sealing rubber ring may be arranged inside the air pipe 602 to seal the connection between the air extraction pipe 601 and the air pipe 602 .

[0044] In some embodiments, the material of the soft water pipe 401 can be selected from PVC plastic hose, and the material of the air extraction pipe 601 can be selected from ordinary plastic hose.

[0045] So far, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0046] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A triaxial test device for marine soft soil, characterized in that: The marine soft soil triaxial test device comprises a pressure chamber (2), an air extraction assembly and a water supply mechanism, one end of the air extraction assembly is connected to the top of the pressure chamber (2), and the air extraction assembly comprises a vacuum air pump (6) for extracting air from the pressure chamber (2), a confining pressure control pipe (201) is provided at the bottom of the pressure chamber (2), the water supply mechanism is detachably connected to the confining pressure control pipe (201), and can inject water into the pressure chamber (2) based on the height difference between the water supply mechanism and the pressure chamber (2) and / or the vacuum pressure formed in the pressure chamber (2), and the confining pressure control pipe (201) is provided with a control valve (203) for controlling its on / off state.

2. The marine soft soil triaxial test device according to claim 1, characterized in that: The water supply mechanism comprises a water storage tank (4) and a soft water pipe (401), one end of the soft water pipe (401) extends into the bottom of the water storage tank (4) through a water outlet at the top of the water storage tank (4), and the other end of the soft water pipe (401) is connected to the confining pressure control pipe (201); The water supply mechanism further comprises a support structure (5) with adjustable support height, and the water storage tank (4) is supported on the support structure (5) so that the liquid level of the water storage tank (4) can be changed by changing the support height of the support structure (5).

3. The marine soft soil triaxial test device according to claim 2, characterized in that: A sealing ring (402) is provided in the water outlet for sealing the gap between the soft water pipe (401) and the water tank (4) at the position where the soft water pipe (401) passes through the water outlet. An air valve is provided on the top of the water tank (4) for controlling the connection between the water tank (4) and the outside.

4. The marine soft soil triaxial test device according to claim 2, characterized in that: The top periphery of the water storage tank (4) is formed with a holder (403) protruding outward, and when the water storage tank (4) is inserted into the support structure (5) from the top of the support structure (5), the holder (403) is supported on the top of the support structure (5).

5. The marine soft soil triaxial test device according to claim 2, characterized in that: The marine soft soil triaxial test device further comprises a platform (3), and the support structure (5) comprises a plurality of square brackets (501) stacked in a direction perpendicular to the platform (3); The support structure (5) further comprises a plurality of fixing members, which are used to detachably fix and connect the upper and lower layers of the square brackets (501), so as to reduce or increase the height difference between the bottom surface of the water storage tank (4) and the liquid level of the pressure chamber (2) by changing the number of layers of the stacked square brackets (501).

6. The marine soft soil triaxial test device according to claim 5, characterized in that: The fixing member comprises a bolt (505) and a nut (506). When the screw rod of the bolt (505) passes through the connection between the upper and lower layers of the square brackets (501) from above or below, the nut (506) is screwed in from the tail end of the screw rod.

7. The marine soft soil triaxial test device according to claim 5, characterized in that: A first support plate (502) and a second support plate (503) are sequentially arranged along the vertical direction of the square support (501); a through hole matching the external shape of the water tank (4) is arranged at the center of each of the first support plate (502) and the second support plate (503); the through hole is used for inserting the water tank (4); the square support (501) comprises a plurality of pillars (504); and the pillars (504) are supported between the first support plate (502) and the second support plate (503).

8. The marine soft soil triaxial test device according to claim 7, characterized in that: The edges of the first support plate (502) and the second support plate (503) are extended away from the through hole to increase the support area of ​​the first support plate (502) and the second support plate (503), and the edges of the first support plate (502) and the second support plate (503) are provided with a plurality of fixing holes for fixing members to pass through.

9. The marine soft soil triaxial test device according to claim 1, characterized in that: The vacuum assembly further comprises an air suction pipe (601) and an air pipe (602). The air pipe (602) is arranged at the top of the pressure chamber (2) for allowing air to circulate in the pressure chamber (2). One end of the air suction pipe (601) is detachably connected to the air pipe (602), and the other end is connected to the vacuum pump (6). The pressure chamber (2) further comprises an air cover. When the pressure chamber (2) reaches a vacuum, the air suction pipe (601) is disconnected from the air pipe (602), and the air cover is connected to the air pipe (602) to prevent external air from entering the pressure chamber (2) through the air pipe (602).

10. The marine soft soil triaxial test device according to claim 9, characterized in that: The air pipe (602) and the air extraction pipe (601) are connected by threads, and a sealing rubber ring is arranged inside the air pipe (602) for sealing the connection between the air extraction pipe (601) and the air pipe (602).

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