An axial loading system suitable for deep-sea pressure-maintained core triaxial testing

Abstract

The invention discloses an axial loading system suitable for deep-sea pressure-maintained core triaxial test, comprising a hydraulic loading component, wherein the hydraulic loading component has a first substrate; the first substrate has a hollow cylindrical structure with one end open, a hydraulic cylinder is arranged at the open end of the first substrate, an outer wall surface of the hydraulic cylinder and an inner wall surface of the first substrate are excessively matched, a hydraulic injection chamber is coaxially arranged at the end of the hydraulic cylinder, a hydraulic rod is coaxially arranged inside the hydraulic cylinder, the hydraulic rod passes through the first substrate, a sliding block is coaxially fixed on the hydraulic rod, the sliding block and the inner side wall of the hydraulic cylinder are excessively matched, a limiting portion is fixed on the lower annular surface of the sliding block, a compression spring is arranged inside the hydraulic cylinder, and the compression spring is coaxial with the hydraulic rod; the invention can realize continuous loading of the pressure-maintained core through the arrangement of the hydraulic loading component, and can also ensure that the free end of the hydraulic rod continuously and evenly applies load to the end face of the pressure-maintained core to obtain accurate test data.

Description

Technical Field

[0001] The invention relates to the technical field of deep-sea geotechnical engineering, and in particular to an axial loading system suitable for deep-sea pressure-maintained core triaxial testing. Background Art

[0002] Drilling coring of seabed resources is the ultimate means of marine geological exploration and the only means to obtain geological reserves. Drilling coring is also one of the important means of marine engineering geological survey. Using ocean drilling ships to drill the seabed is currently the main way to explore marine resources, but this method is not economical, and the tonnage of marine drilling ships is large and the consumption is high. For the investigation of seabed hydrate resources and marine engineering geological investigation, the drilling depth is generally tens of meters to 200 meters. The development trend of this type of drilling is to use general-purpose scientific research ships equipped with underwater drilling rigs that can operate autonomously on the seabed for drilling. In order to understand whether there are hydrates in the sediments or hydrocarbon leakage, it is usually required to maintain the pressure of deep-sea sediment cores, that is, in the process of lifting the cores from the seabed to the sea surface, keep the seabed pressure unchanged, otherwise the hydrocarbon gas will be released as the pressure decreases. If you want to further clarify the hydraulic fracturing mechanism of deep rock mass and the failure mechanism under triaxial stress state, you must conduct indoor simulated high-temperature and high-pressure hydraulic fracturing and triaxial core tests to obtain the physical property parameters of the core, so as to reflect the relevant characteristics of deep underground rock mass. As a result, corresponding test devices have been developed one after another to carry out simulation tests.

[0003] The prior art discloses a device for generating an axial load in a drill string assembly (US20220049560A1), which includes a hollow cylinder and a spring-loaded flow plunger rod with a key, the rod and the key forming a subassembly. The hollow cylindrical barrel is provided with a sealing ring and longitudinal grooves on both sides arranged along the inner generatrix of the cylindrical barrel, and the grooves accommodate the plunger rod with longitudinal and transverse clearances, so that the key can move along the grooves together with the plunger rod passing through. The length of the longitudinal grooves on both sides depends on the maximum length of the working stroke of the flow plunger rod. The invention improves the operating efficiency of the drill string and the expanded functional capabilities through the above technical means, but the above axial loading device still has deficiencies in the use process of the axial loading test of the pressure-retaining core. Summary of the invention

[0004] The purpose of the present invention is to provide an axial loading system suitable for deep-sea pressure-maintained core triaxial testing, so as to solve the problems of limited maximum load that can be provided by existing devices, rigid deformation of shaft rod parts under axial force, poor sealing between the pressure head and the end face of the pressure-maintained core, poor heat shrinkage effect when using a heat shrink sleeve, and excessive heat shrinkage.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an axial loading system suitable for deep-sea pressure-maintained core triaxial test, comprising: a hydraulic loading assembly, the hydraulic loading assembly having a first substrate; the first substrate having a hollow cylindrical structure with one end open, a hydraulic cylinder body being provided at the open end of the first substrate, the outer wall surface of the hydraulic cylinder body and the inner wall surface of the first substrate being excessively matched, a hydraulic injection chamber being coaxially provided at the end of the hydraulic cylinder body, a hydraulic rod being coaxially provided inside the hydraulic cylinder body, the hydraulic rod passing through the first substrate, a sliding block being coaxially fixed on the hydraulic rod, the sliding block and the inner side wall of the hydraulic cylinder body being excessively matched, a limiting portion being fixed on the lower annular surface of the sliding block, a compression spring being provided inside the hydraulic cylinder body, the compression spring being coaxial with the hydraulic rod, and the compression spring being located below the limiting portion.

[0006] The axial loading system suitable for deep-sea pressure-retaining core triaxial test can realize continuous loading of the pressure-retaining core through the setting of the hydraulic loading component, improve the sealing of the pressure-retaining core during loading, and ensure that the free end of the hydraulic rod continuously and evenly applies load to the end face of the pressure-retaining core to obtain accurate test data.

[0007] According to one embodiment of the present invention, the axial loading system suitable for deep-sea pressure-maintained core triaxial testing also includes an auxiliary loading component, the auxiliary loading component has an auxiliary loading base, the auxiliary loading base has a cylindrical hollow structure, an assembly body is coaxially arranged inside the auxiliary loading base, and a base plate is arranged at the bottom of the auxiliary loading base.

[0008] The axial loading system suitable for deep-sea pressure-maintained core triaxial test can protect the free end of the hydraulic rod and improve the coaxiality between the hydraulic rod and the pressure-maintained core by setting an auxiliary loading matrix.

[0009] According to one embodiment of the present invention, the assembly body has a main shaft sleeve and a side protective sleeve, a ball is arranged between the main shaft sleeve and the side protective sleeve, the main shaft sleeve is detachably connected to the end of the hydraulic rod, and the side protective sleeve is detachably connected to the inner wall of the auxiliary loading base.

[0010] This axial loading system is suitable for deep-sea pressure-maintained core triaxial test. The bottom plate is installed on the bottom of the buffer through a detachable main shaft sleeve and a side protective sleeve, which is convenient for replacing bottom plates and pressure heads of different sizes to match the different cross-sectional sizes of the pressure-maintained core. On the other hand, after the loading test is completed, viscous substances such as hydraulic oil may remain on the contact surface between the bottom plate and the pressure head to cause adhesion. Since the side protective sleeve and the hydraulic rod provided by the device are rotatably connected through the main shaft sleeve, for the above situation, the device can rotate the auxiliary loading base and use centrifugal force to make the pressure head easy to detach from the bottom plate, so as to avoid damage to the auxiliary loading base when the pressure head is directly removed.

[0011] According to an embodiment of the present invention, a receiving chamber is provided inside the auxiliary loading base, the receiving chamber is located below the assembly body, and a buffer is provided inside the receiving chamber.

[0012] According to one embodiment of the present invention, the buffer member has an upper pressure plate and a lower pressure plate arranged in parallel, the upper pressure plate and the lower pressure plate have equal-sized circular plate structures, the axes of the upper pressure plate and the lower pressure plate coincide, and a pressure column is coaxially arranged between the upper pressure plate and the lower pressure plate.

[0013] The axial loading system suitable for deep-sea pressure-maintained core triaxial test can evenly distribute the load force provided by the device to the pressure head through the arrangement of the pressure-bearing column in the buffer, thereby improving the accuracy of the pressure-maintained core axial loading test result.

[0014] According to one embodiment of the present invention, an upper spiral buffer is provided circumferentially on the upper pressure plate, and a lower spiral buffer is provided circumferentially on the lower pressure plate. The number of the upper spiral buffers and the lower spiral buffers are the same and correspond one to one. The upper spiral buffers and the lower spiral buffers both have an axis and a pressure transmission plate, and the pressure transmission plate has a spiral plate-like structure.

[0015] The axial loading system suitable for deep-sea pressure-maintained core triaxial test can increase the maximum load that a pressure column can withstand through the arrangement of an upper spiral buffer and a lower spiral buffer, which is beneficial to the improvement of the upper limit of loading during the test.

[0016] According to an embodiment of the present invention, the spiral directions of the pressure transmission plates of the upper spiral buffer and the lower spiral buffer are opposite, and an elastic column is provided on the end of any upper spiral buffer or the lower spiral buffer.

[0017] The axial loading system is suitable for deep-sea pressure-maintained core triaxial test. Through the setting of elastic columns, a force buffer space can be provided for the shaft rod, thereby effectively preventing the shaft rod from undergoing rigid deformation when the device is used under long-term high load.

[0018] According to one embodiment of the present invention, the axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes an installation base, the installation base has a base, a test base is provided on the base, the test base has a load-bearing limit plate, a test operation window is opened on the test base, a pressure-maintained core is placed inside the test operation window, and a hydraulic access component is provided on the top of the test base.

[0019] According to one embodiment of the present invention, the axial loading system suitable for deep-sea pressure-maintained core triaxial testing also includes an auxiliary fixing sleeve, which has a circular base, the circular base has a circular plate-like structure, and a plurality of fixed bent plates are circumferentially arranged on a circular surface of the circular base, the ends of the fixed bent plates have a bent plate structure bent toward the outside of the circular base, and auxiliary grooves are provided between adjacent fixed bent plates.

[0020] The axial loading system suitable for deep-sea pressure-retaining core triaxial test can not only ensure the coaxiality of the pressure-retaining core and the pressure head during loading by setting the auxiliary fixing sleeve, but also prevent the pressure head from tilting in the horizontal direction by setting the auxiliary fixing sleeve when the pressure-retaining core is finally broken due to stress, resulting in an uneven end face of the pressure-retaining core. At the same time, it can also prevent rock debris generated on the end face of the pressure-retaining core from splashing out from the gap between the pressure head and the end face of the pressure-retaining core when the pressure-retaining core is broken.

[0021] According to one embodiment of the present invention, the axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes a heat shrinkable protective sleeve, which has a sleeve body, and a heat shrinkable groove is arranged on the inner wall of the sleeve body. The heat shrinkable groove is composed of a circular groove with one end open and a square groove. An annular through groove is opened inside the side wall of the sleeve body, and the annular through groove passes through the heat shrinkable groove. A clamp component is installed inside the annular through groove, and a clamp end release groove is opened inward from the outer wall of the sleeve body, wherein the position of the heat shrinkable groove corresponds to the clamping position of the pressure head and the pressure-maintained core.

[0022] This axial loading system suitable for deep-sea pressure-maintaining core triaxial test can not only improve the sealing between the pressure head and the end face of the pressure-maintaining core, avoid liquid leakage, and protect the surface of the device through the setting of the heat shrinkable protective sleeve, but also can judge the shrinkage amount of the heat shrinkable protective sleeve on the circumference of the pressure-maintaining core through the clamp component, so as to obtain a better heat shrinkage effect and avoid excessive heat shrinkage. Specifically, on the one hand, the heat shrinkage groove can enhance the heat shrinkage effect of the casing body, and further improve the sealing between the pressure head and the end face of the pressure-maintaining core. On the other hand, during the loading test, if there is liquid leakage, it will first flow to the heat shrinkage groove to intercept the leaking liquid and prevent it from being directly discharged onto the device and corroding the surface of the device.

[0023] On the other hand, the heat shrink grooves are connected by an annular through groove, and a clamp component is installed inside the annular through groove. After the heat shrink protective sleeve is shrunk by heating with a hot air blower, the clamp component is also rolled up accordingly, thereby strengthening the clamping tightness between the pressure head and the pressure holding core. The shrinkage amount of the heat shrink protective sleeve on the circumference of the pressure holding core can also be judged by the length of the clamp component extending from the release groove at the end of the clamp, thereby obtaining a better heat shrinkage effect, avoiding excessive heat shrinkage, causing local thinning of the side wall of the casing body, and reducing the risk of rupture of the casing body. Among them, the clamp component is preferably a clamp with a scale or easy to distinguish length change and good flexibility.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This is an axial loading system suitable for deep-sea pressure-maintained core triaxial test. The bottom plate is installed on the bottom of the buffer through a detachable main shaft sleeve and a side protective sleeve, which is convenient for replacing bottom plates and pressure heads of different sizes to match different cross-sectional sizes of pressure-maintained cores.

[0026] 2. This axial loading system is suitable for deep-sea pressure-maintained core triaxial test. Through the setting of the auxiliary loading matrix, centrifugal force can be used to facilitate the separation of the pressure head from the bottom plate, avoiding the damage of the auxiliary loading matrix when the pressure head is directly removed.

[0027] 3. The axial loading system suitable for deep-sea pressure-maintained core triaxial test can increase the maximum load that the pressure column can withstand through the arrangement of the upper spiral buffer and the lower spiral buffer, which is beneficial to the improvement of the upper limit of the load during the test.

[0028] 4. This axial loading system is suitable for deep-sea pressure-maintained core triaxial test. Through the setting of elastic columns, it can provide a force buffer space for the shaft rod, effectively avoiding the rigid deformation of the shaft rod when the device is used for a long time under high load.

[0029] 5. This axial loading system suitable for deep-sea pressure-retaining core triaxial test can not only ensure the coaxiality of the pressure-retaining core and the pressure head during loading through the setting of the auxiliary fixing sleeve, but also prevent the pressure head from tilting in the horizontal direction. At the same time, it also prevents the rock debris generated on the end face of the pressure-retaining core from splashing out from the gap between the pressure head and the end face of the pressure-retaining core when the pressure-retaining core breaks.

[0030] 6. This axial loading system suitable for deep-sea pressure-maintained core triaxial test can not only improve the sealing between the pressure head and the end face of the pressure-maintained core to avoid liquid seepage and protect the surface of the device through the setting of the heat shrinkable protective sleeve, but also can judge the shrinkage amount of the heat shrinkable protective sleeve on the circumference of the pressure-maintained core through the clamp component, thereby obtaining a better heat shrinkage effect and avoiding excessive heat shrinkage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic structural diagram of a preferred embodiment of an axial loading system suitable for deep-sea pressure-maintained core triaxial test provided by the present invention;

[0032] Figure 2 for Figure 1 A schematic diagram of the structure of the hydraulic loading assembly and the auxiliary loading assembly shown;

[0033] Figure 3 for Figure 2 The main view;

[0034] Figure 4 for Figure 3The AA section view is shown;

[0035] Figure 5 for Figure 4 Enlarged view of middle Ⅰ-Ⅰ;

[0036] Figure 6 for Figure 5 A schematic diagram of the structure of the buffer shown;

[0037] Figure 7 for Figure 6 Enlarged view of middle II-II;

[0038] Figure 8 for Figure 1 The schematic diagram of the assembly structure of the pressure-maintaining core and the auxiliary fixing sleeve and the heat-shrinkable protective sleeve is shown;

[0039] Fig. 9 for Figure 8 A schematic diagram of the structure of the auxiliary fixing sleeve shown;

[0040] Fig.10 for Figure 8 The structural schematic diagram of the heat shrinkable protective sleeve shown;

[0041] Fig.11 for Fig.10 A partial cutaway view of

[0042] Fig.12 for Fig.11 Enlarged view of middle III-III;

[0043] Fig.13 for Fig.11 A top view of the device and a schematic diagram of its assembly with the clamp component.

[0044] In the figure: 1, hydraulic loading assembly; 11, first base; 12, hydraulic cylinder; 13, hydraulic injection chamber; 14, hydraulic rod; 15, sliding block; 151, limiter; 16, compression spring; 2, auxiliary loading assembly; 21, auxiliary loading base; 22, assembly assembly; 221, main shaft sleeve; 222, side protection sleeve; 223, ball; 23, accommodating chamber; 24, buffer; 241, upper pressure plate; 242, lower pressure plate; 243, pressure column; 244, upper spiral buffer; 245, lower spiral buffer Stamping; 246, shaft; 247, pressure transmission plate; 248, elastic column; 25, bottom plate; 3, mounting base; 31, base; 32, test base; 321, load-bearing limit plate; 322, test operation window; 33, pressure-maintaining core; 34, hydraulic access component; 4, auxiliary fixing sleeve; 41, circular base; 42, fixed bent plate; 43, auxiliary groove; 5, heat shrink protective sleeve; 51, sleeve body; 52, heat shrink groove; 53, annular through groove; 54, clamp component; 55, clamp end release groove; 6, pressure head. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] See also Figure 1-Figure 4 An embodiment of the present invention is as follows: an axial loading system suitable for deep-sea pressure-maintained core triaxial test, comprising a hydraulic loading component 1, the hydraulic loading component 1 having a first substrate 11; the first substrate 11 having a hollow cylindrical structure with one end open, a hydraulic cylinder body 12 is provided at the open end of the first substrate 11, the outer wall surface of the hydraulic cylinder body 12 and the inner wall surface of the first substrate 11 are excessively matched, a hydraulic injection chamber 13 is coaxially provided at the end of the hydraulic cylinder body 12, a hydraulic rod 14 is coaxially provided inside the hydraulic cylinder body 12, the hydraulic rod 14 passes through the first substrate 11, a sliding block 15 is coaxially fixed on the hydraulic rod 14, the sliding block 15 and the inner side wall of the hydraulic cylinder body 12 are excessively matched, a limiting portion 151 is fixed on the lower annular surface of the sliding block 15, a compression spring 16 is provided inside the hydraulic cylinder body 12, the compression spring 16 is coaxial with the hydraulic rod 14, and the compression spring 16 is located below the limiting portion 151.

[0047] This axial loading system suitable for deep-sea pressure-maintaining core triaxial testing can achieve continuous loading of the pressure-maintaining core 33 through the setting of the hydraulic loading component 1, and can also improve the sealing of the pressure-maintaining core 33 during the loading process, and can also ensure that the free end of the hydraulic rod 14 continuously and evenly applies load to the end face of the pressure-maintaining core 33 to obtain accurate test data.

[0048] See also Figure 1-Figure 5 The axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes an auxiliary loading component 2, which has an auxiliary loading base 21. The auxiliary loading base 21 has a cylindrical hollow structure, an assembly body 22 is coaxially arranged inside the auxiliary loading base 21, and a bottom plate 25 is arranged at the bottom of the auxiliary loading base 21.

[0049] The axial loading system suitable for deep-sea pressure-maintained core triaxial test can protect the free end of the hydraulic rod 14 and improve the coaxiality between the hydraulic rod 14 and the pressure-maintained core 33 by setting the auxiliary loading base 21.

[0050] See also Figure 5The assembly body 22 has a main shaft sleeve 221 and a side protective sleeve 222, and a ball 223 is arranged between the main shaft sleeve 221 and the side protective sleeve 222. The main shaft sleeve 221 is detachably connected to the end of the hydraulic rod 14, and the side protective sleeve 222 is detachably connected to the inner wall of the auxiliary loading base 21.

[0051] This axial loading system suitable for deep-sea pressure-maintained core triaxial test, installs the bottom plate 25 on the bottom of the buffer 24 through a detachable main shaft sleeve 221 and a side protective sleeve 222, so that different sizes of bottom plates 25 and pressure heads 6 can be replaced to match different cross-sectional sizes of the pressure-maintained core 33. On the other hand, after the loading test is completed, viscous substances such as hydraulic oil may remain on the contact surface between the bottom plate 25 and the pressure head 6 to cause adhesion. Since the side protective sleeve 222 and the hydraulic rod 14 provided by the device are rotatably connected through the main shaft sleeve 221, for the above situation, the device can rotate the auxiliary loading base 21 and use centrifugal force to make the pressure head 6 easy to detach from the bottom plate 25, so as to avoid the situation where the auxiliary loading base 21 is damaged when the pressure head 6 is directly removed.

[0052] See also Figure 5-Figure 6 A receiving chamber 23 is provided inside the auxiliary loading base 21 . The receiving chamber 23 is located below the assembly body 22 . A buffer member 24 is provided inside the receiving chamber 23 .

[0053] See also Figure 6-Figure 7 The buffer member 24 has an upper pressure plate 241 and a lower pressure plate 242 which are arranged in parallel. The upper pressure plate 241 and the lower pressure plate 242 have an equal-sized circular plate structure. The axes of the upper pressure plate 241 and the lower pressure plate 242 coincide with each other. A pressure column 243 is coaxially arranged between the upper pressure plate 241 and the lower pressure plate 242.

[0054] The axial loading system suitable for deep-sea pressure-retaining core triaxial test can evenly distribute the load force provided by the device to the pressure head 6 through the arrangement of the pressure-retaining column 243 in the buffer 24, thereby improving the accuracy of the axial loading test results of the pressure-retaining core 33.

[0055] See also Figure 6-Figure 7 An upper spiral buffer 244 is circumferentially provided on the upper pressure plate 241, and a lower spiral buffer 245 is circumferentially provided on the lower pressure plate 242. The number of the upper spiral buffers 244 and the lower spiral buffers 245 are the same and correspond one to one. Both the upper spiral buffers 244 and the lower spiral buffers 245 have a shaft 246 and a pressure transmission plate 247, and the pressure transmission plate 247 has a spiral plate structure.

[0056] The axial loading system suitable for deep-sea pressure-maintained core triaxial test can increase the maximum load that the pressure column 243 can withstand through the arrangement of the upper spiral buffer 244 and the lower spiral buffer 245, which is beneficial to the improvement of the upper limit of the load during the test.

[0057] See also Figure 6-Figure 7 The spiral directions of the pressure transfer plates 247 of the upper spiral buffer 244 and the lower spiral buffer 245 are opposite, and an elastic column 248 is provided on the end of any upper spiral buffer 244 or the lower spiral buffer 245.

[0058] This axial loading system suitable for deep-sea pressure-maintained core triaxial testing can provide a force buffer space for the shaft 246 through the arrangement of the elastic column 248, effectively preventing the shaft 246 from undergoing rigid deformation when the device is used under long-term high-load conditions.

[0059] See also Figure 1 The axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes a mounting base 3, the mounting base 3 has a base 31, a test base 32 is provided on the base 31, the test base 32 has a load-bearing limit plate 321, a test operation window 322 is opened on the test base 32, a pressure-maintained core 33 is placed inside the test operation window 322, and a hydraulic access component 34 is provided on the top of the test base 32.

[0060] See also Figure 8-Figure 9 The axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes an auxiliary fixing sleeve 4, which has a circular base 41. The circular base 41 has a circular plate-like structure. A plurality of fixed bent plates 42 are circumferentially arranged on a circular surface of the circular base 41. The ends of the fixed bent plates 42 have a bent plate structure bent toward the outside of the circular base 41, and auxiliary grooves 43 are provided between adjacent fixed bent plates 42.

[0061] This axial loading system suitable for deep-sea pressure-retaining core triaxial test can not only ensure the coaxiality of the pressure-retaining core 33 and the pressure head 6 during loading through the setting of the auxiliary fixing sleeve 4, but also prevent the pressure head 6 from tilting in the horizontal direction due to the uneven end face of the pressure-retaining core 33 due to the final fracture under force during the loading test, and also prevent the rock debris generated on the end face of the pressure-retaining core 33 from splashing out from the gap between the pressure head 6 and the end face of the pressure-retaining core 33 when the pressure-retaining core 33 is fractured.

[0062] See also Figure 8 , Fig.10The axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes a heat shrinkable protective sleeve 5, which has a sleeve body 51. A heat shrinkable groove 52 is arranged on the inner wall of the sleeve body 51. The heat shrinkable groove 52 consists of a circular groove with one end open and a square groove. An annular through groove 53 is opened inside the side wall of the sleeve body 51. The annular through groove 53 runs through the heat shrinkable groove 52. A clamp component 54 is installed inside the annular through groove 53. A clamp end release groove 55 is opened inwardly from the outer wall of the sleeve body 51, wherein the position of the heat shrinkable groove 52 corresponds to the clamping position of the pressure head 6 and the pressure-maintained core 33.

[0063] This axial loading system suitable for deep-sea pressure-maintaining core triaxial test can not only improve the sealing between the pressure head 6 and the end face of the pressure-maintaining core 33, avoid liquid leakage, and protect the surface of the device through the setting of the heat shrinkable protective sleeve 5, but also can judge the shrinkage amount of the heat shrinkable protective sleeve 5 on the circumference of the pressure-maintaining core 33 through the clamp component 54, so as to obtain a better heat shrinkage effect and avoid excessive heat shrinkage. Specifically, on the one hand, the heat shrinkage groove 52 can enhance the heat shrinkage effect of the sleeve body 51, and further improve the sealing between the pressure head 6 and the end face of the pressure-maintaining core 33. On the other hand, during the loading test, if there is liquid leakage, it will first flow to the heat shrinkage groove 52, so as to intercept the leaked liquid and prevent it from being directly discharged onto the device and corroding the surface of the device.

[0064] On the other hand, the heat shrink grooves 52 are connected by an annular through groove 53, and a clamp component 54 is installed inside the annular through groove 53. After the heat shrink protective sleeve 5 is shrunk by heating with a hot air blower, the clamp component 54 is also rolled up accordingly, thereby strengthening the clamping tightness between the pressure head 6 and the pressure retaining core 33. The shrinkage amount of the heat shrink protective sleeve 5 on the pressure retaining core 33 in the circumferential direction can also be judged by the length of the clamp component 54 extending from the release groove 55 at the end of the clamp, thereby obtaining a better heat shrinkage effect, avoiding excessive heat shrinkage, causing local thinning of the side wall of the sleeve body 51, and reducing the risk of rupture of the sleeve body 51. Among them, the clamp component 54 is preferably a clamp with a scale or easy to distinguish length changes and good flexibility.

[0065] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An axial loading system suitable for deep-sea pressure-maintained core triaxial testing, comprising: A hydraulic loading assembly (1), wherein the hydraulic loading assembly (1) comprises a first base body (11); Features: The first base body (11) has a hollow cylindrical structure with one end open, a hydraulic cylinder body (12) is provided at the open end of the first base body (11), the outer wall surface of the hydraulic cylinder body (12) and the inner wall surface of the first base body (11) are overfitted, a hydraulic injection chamber (13) is coaxially provided at the end of the hydraulic cylinder body (12), a hydraulic rod (14) is coaxially provided inside the hydraulic cylinder body (12), the hydraulic rod (14) passes through the first base body (11), a sliding block (15) is coaxially fixed on the hydraulic rod (14), the sliding block (15) and the inner side wall of the hydraulic cylinder body (12) are overfitted, a limiting portion (151) is fixed on the lower annular surface of the sliding block (15), a compression spring (16) is provided inside the hydraulic cylinder body (12), the compression spring (16) is coaxial with the hydraulic rod (14), and the compression spring (16) is located below the limiting portion (151); The axial loading system suitable for deep-sea pressure-maintained core triaxial test further comprises an auxiliary loading component (2), the auxiliary loading component (2) comprising an auxiliary loading base (21), the auxiliary loading base (21) having a cylindrical hollow structure, a mounting body (22) coaxially disposed inside the auxiliary loading base (21), and a bottom plate (25) disposed at the bottom of the auxiliary loading base (21); The assembly body (22) comprises a main shaft sleeve (221) and a side protective sleeve (222), a ball (223) being provided between the main shaft sleeve (221) and the side protective sleeve (222), the main shaft sleeve (221) being detachably connected to the end of the hydraulic rod (14), and the side protective sleeve (222) being detachably connected to the inner wall of the auxiliary loading base (21); The auxiliary loading base (21) has a receiving chamber (23) disposed therein, the receiving chamber (23) being located below the assembly body (22), and a buffer (24) being disposed therein; The buffer member (24) comprises an upper pressure plate (241) and a lower pressure plate (242) which are arranged in parallel. The upper pressure plate (241) and the lower pressure plate (242) have a circular plate structure of equal size. The axes of the upper pressure plate (241) and the lower pressure plate (242) coincide with each other. A pressure column (243) is coaxially arranged between the upper pressure plate (241) and the lower pressure plate (242).

2. The axial loading system suitable for deep-sea pressure-maintained core triaxial test according to claim 1, characterized in that: An upper spiral buffer (244) is provided on the lower circumference of the upper pressure plate (241), and a lower spiral buffer (245) is provided on the upper circumference of the lower pressure plate (242). Both the upper spiral buffer (244) and the lower spiral buffer (245) have a shaft (246) and a pressure transmission plate (247), and the pressure transmission plate (247) has a spiral plate structure.

3. The axial loading system suitable for deep-sea pressure-maintained core triaxial test according to claim 2, characterized in that: The spiral directions of the pressure transmission plates (247) of the upper spiral buffer (244) and the lower spiral buffer (245) are opposite, and an elastic column (248) is provided on the end of any one of the upper spiral buffer (244) or the lower spiral buffer (245).

4. An axial loading system suitable for deep-sea pressure-maintained core triaxial testing according to any one of claims 1 to 3, characterized in that: The axial loading system suitable for deep-sea pressure-maintained core triaxial testing also includes a mounting base (3), the mounting base (3) having a base (31), a test base (32) being provided on the base (31), the test base (32) having a load-bearing limit plate (321), a test operation window (322) being provided on the test base (32), and a hydraulic access component (34) being provided on the top of the test base (32).

5. The axial loading system suitable for deep-sea pressure-maintained core triaxial test according to claim 4, characterized in that: The axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes an auxiliary fixing sleeve (4), the auxiliary fixing sleeve (4) having a circular base (41), the circular base (41) having a circular plate-like structure, a plurality of fixed bent plates (42) being circumferentially arranged on a circular surface of the circular base (41), the ends of the fixed bent plates (42) having a bent plate structure bent toward the outside of the circular base (41), and auxiliary grooves (43) being provided between adjacent fixed bent plates (42).

6. The axial loading system suitable for deep-sea pressure-maintained core triaxial test according to claim 5, characterized in that: The axial loading system suitable for deep-sea pressure-maintained core triaxial test also includes a heat shrinkable protective sleeve (5), the heat shrinkable protective sleeve (5) comprising a sleeve body (51), a heat shrinkable groove (52) being provided on the inner side wall of the sleeve body (51), an annular through groove (53) being provided inside the side wall of the sleeve body (51), and the annular through groove (53) passing through the heat shrinkable groove (52).

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