阅读说明：本技术 一种能结合ct扫描的大载荷岩心夹持器及真三轴实验装置 (Large-load rock core holder capable of combining CT scanning and true triaxial experimental device ) 是由 李智 林梦英 方博涵 张正欣 程军 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种能结合CT扫描的大载荷岩心夹持器及真三轴实验装置,所述的大载荷岩心夹持器包括上传力端头、下传力端头和筒体,在筒体的中空腔体内设有样品腔和4个胶囊容纳腔,位于左、右侧胶囊容纳腔中的两个胶囊体用于X向柔性加载传力,位于前、后侧胶囊容纳腔中的两个胶囊体用于Y向柔性加载传力；每个胶囊体上均具有内翻裙边接口,每个内翻裙边接口内均过盈连接有密封堵头,在每个密封堵头上均穿设有与胶囊体内腔相连通的注液管,所有注液管均穿出上传力端头；并且,在下传力端头的中心穿设有Z向加载活塞杆。所述的大载荷真三轴实验装置包括所述的大载荷岩心夹持器和Z向加载缸及X向、Y向、Z向液压加载系统。(The invention discloses a large-load rock core holder capable of combining CT scanning and a true triaxial experimental device, wherein the large-load rock core holder comprises an upper force transmission end, a lower force transmission end and a barrel body, a sample cavity and 4 capsule containing cavities are arranged in a hollow cavity of the barrel body, two capsule bodies positioned in the left and right capsule containing cavities are used for flexible loading and force transmission in the X direction, and two capsule bodies positioned in the front and rear capsule containing cavities are used for flexible loading and force transmission in the Y direction; each capsule body is provided with an inward-turned skirt edge interface, a sealing plug is connected in each inward-turned skirt edge interface in an interference fit manner, each sealing plug is provided with a liquid injection pipe communicated with the inner cavity of the capsule body in a penetrating manner, and all the liquid injection pipes penetrate out of the upper force transmission end head; and a Z-direction loading piston rod is arranged in the center of the lower force transmission end in a penetrating way. The large-load true triaxial experimental device comprises the large-load rock core holder, a Z-direction loading cylinder and X-direction, Y-direction and Z-direction hydraulic loading systems.)

1. A large-load rock core holder capable of being combined with CT scanning comprises an upper force transmission end, a lower force transmission end and a cylinder body which is made of non-metal materials and can be penetrated by X rays, wherein the two ends of the cylinder body are open, a circumferential pressure-bearing carbon fiber sleeve is arranged on the outer circumference of the cylinder body, and at least one pair of axial pressure-bearing carbon fiber rings are symmetrically arranged on the outer circumference of the cylinder body; the method is characterized in that: be equipped with sample chamber and 4 capsules of symmetric distribution in the left and right, preceding, 4 sides in back of this sample chamber in the cavity of this barrel and hold the chamber, wherein: the two capsule bodies positioned in the left and right capsule accommodating cavities are used for X-direction flexible loading and force transmission, and the two capsule bodies positioned in the front and rear capsule accommodating cavities are used for Y-direction flexible loading and force transmission; each capsule body is provided with an inward-turned skirt edge interface, a sealing plug is connected in each inward-turned skirt edge interface in an interference fit manner, each sealing plug is provided with a liquid injection pipe communicated with the inner cavity of the capsule body in a penetrating manner, and all the liquid injection pipes penetrate out of the upper force transmission end head; and a Z-direction loading piston rod is arranged in the center of the lower force transmission end in a penetrating way.

2. The heavy-load core holder as recited in claim 1, wherein: the top and the bottom of each capsule body are respectively provided with an elastic buffer gasket and a rigid bearing block; an axial rigid pressing block is arranged between the upper force transmission end and the end part of the sample cavity.

3. The heavy-load core holder as recited in claim 1, wherein: the inward turning skirt edge interface is an embedded cylindrical through hole, and the sealing plug is a metal cylinder.

4. The heavy-load core holder as recited in claim 1, wherein: one or more outer convex ring belts are arranged on the outer peripheral surface of the sealing plug.

5. The heavy-load core holder as recited in claim 1, wherein: the force transmission surface of the capsule body is a plane or a curved surface.

6. The heavy-load core holder as recited in claim 1, wherein: at least one group of cantilevers forming central symmetry is fixedly arranged at the outer peripheral part of the upper force transmission end and the outer peripheral part of the lower force transmission end, mirror symmetry is formed between the upper cantilever and the lower cantilever, and axial pressure-bearing carbon fiber rings are arranged on each group of upper and lower cantilevers forming mirror symmetry.

7. The heavy-load core holder as recited in claim 6, wherein: the upper arc end and the lower arc end of each axial pressure-bearing carbon fiber ring are respectively and fixedly arranged in an opening of a U-shaped limiting seat, and the distance between the bottom surface of the upper U-shaped limiting seat and the top surface of the lower U-shaped limiting seat is matched with the distance between the top surface of the upper cantilever and the bottom surface of the lower cantilever, so that each axial pressure-bearing carbon fiber ring can not only tension the upper cantilever and the lower cantilever, but also be conveniently assembled and disassembled.

8. The heavy-load core holder as recited in claim 7, wherein: the upper limiting baffle attached to the outer side of the upper U-shaped limiting seat is detachably connected to the upper cantilever, the lower limiting baffle attached to the outer side of the lower U-shaped limiting seat is detachably connected to the lower cantilever, and the upper limiting baffle and the lower limiting baffle form a mirror symmetry relation.

9. The utility model provides a can combine CT scanning's true triaxial experimental apparatus of heavy load which characterized in that: the large-load core holder comprises the large-load core holder as claimed in any one of claims 1 to 8, a Z-direction loading cylinder, a Z-direction hydraulic loading system, an X-direction hydraulic loading system and a Y-direction hydraulic loading system, wherein the Z-direction loading cylinder is connected with a lower force transmission end head in a sealing manner, a piston is arranged in the Z-direction loading cylinder, a Z-direction loading piston rod is fixedly connected with the piston, a hydraulic conveying channel communicated with a piston cavity is arranged at the bottom of the Z-direction loading cylinder, the hydraulic conveying channel is connected with a Z-direction hydraulic loading system through a pressure-resistant hose, liquid injection pipes on two capsule bodies used for X-direction flexible loading and force transmission in the large-load core holder are connected with the X-direction hydraulic loading system through the pressure-resistant hose, and liquid injection pipes on two capsule bodies used for Y-direction flexible loading and force transmission in the large-load core holder are connected with a Y-direction hydraulic loading system through pressure-resistant hoses.

10. The high-load true triaxial experimental apparatus according to claim 9, wherein: a buffer spacer is arranged between the force transmission surface of the capsule body and the force bearing surface of the sample, and the buffer spacer is made of non-metal materials.

Technical Field

The invention relates to a large-load rock core holder capable of combining CT scanning and a true triaxial experimental device, and belongs to the technical field of rock mechanics and engineering.

Background

The permeability, mechanical property, crack growth rule and the like of the oil and gas reservoir rock have obvious heterogeneity and anisotropy, so that the research on the seepage characteristic, the mechanical property and the crack growth mechanism of the rock core under the true triaxial stress state has important significance.

In addition, the CT nondestructive scanning technology can realize dynamic characterization of the microstructure in the rock, is an effective method for revealing core seepage characteristics, crack growth mechanisms and the like, and cannot damage the internal structure of the rock, so the CT scanning technology is widely applied to the field of oil and gas field development at home and abroad in recent years. The development of modern engineering technology and the theoretical research of geotechnical mechanics urgently need the experimental equipment which can be really applied and can simultaneously realize CT scanning when true triaxial experiment is carried out so as to realize the omnibearing dynamic monitoring of the structural change in the rock sample, intuitively know the local change, the slight change and the change trend of the internal structure of the rock sample, conveniently master the characters of the rock sample under different stress conditions and know the real dynamic deformation failure mechanism of the rock from a microscopic angle. During CT scanning, the X-ray imaging component and a sample need to rotate 360 degrees relative to each other by a high-precision rotating table, so that the true triaxial experiment device is required to be miniaturized and lightened in weight and the core holder is required to realize independent large-load loading in the three axial directions and cannot influence the penetration of X-rays in order to be used in combination with CT scanning equipment.

Although chinese patent 201510577392.2 discloses a rock true triaxial test system with a CT real-time scanning system, comprising a true triaxial pressure cell, a true triaxial host frame, a loading device, and a CT scanning device; the true triaxial host frame comprises a bottom plate, a top plate, a vertical column and a supporting frame, wherein the bottom plate and the vertical column are supported by the bottom plate; the loading device comprises a counterforce device, a jack and a measuring device; the pressure box, the upright post and the counterforce device positioned in the scanning area of the CT scanning device are all made of carbon fiber materials; this patent has solved the difficult problem that X ray can't pierce through traditional true triaxial testing machine through the horizontal loading system, carbon fiber biography power board and the stand that adopt special design to the CT scanning district, has realized the real-time cooperation of rock true triaxial and CT scanning test, but this patent can only realize that three axial all can only carry out 100kN (being equivalent to 0.1 megapascal) loading power, can not reach the loading requirement on standard rock specimen far away, unable practical application, can only be used in some approximate simulation lab testings on very little sample.

Chinese patent application 201910088014.6 discloses a true triaxial stress seepage coupling test device suitable for X-CT, which realizes independent flexible loading on three axial directions of a core by arranging five capsules in a core holder, although the combination of the true triaxial stress seepage coupling test device and a CT scanning device can be realized, the prior art can know that: the existing force transfer capsules are all capsules made of high-elasticity rubber, when the capsules are used for hydraulic loading, one or more liquid inlet and outlet ports are required to be arranged on a capsule body, the port on the existing force transfer capsule body is a circular opening, and a bolt and nut pressing and sealing connection structure is basically adopted between the circular opening port and an external joint with pressure liquid, and specifically, as shown in fig. 1, the structure is that: the capsule body has one circular opening, and the opening is first expanded with the high elasticity of the capsule body material, and the filling pipe with pre-installed lower pressing nut and lower gasket is then stretched into the capsule body, and the upper gasket is then added and the pressing nut is screwed to make the upper and lower gaskets to press the rubber wall in the interface of the capsule body and deform to realize sealing while adding pressurized liquid. Since the sealing connection structure generates large stress locally and there is a distinct boundary between the upper and lower gaskets and the capsule wall, so as to shear the rubber wall at the interface of the capsule body, when the liquid pressure reaches several mpa or even below one mpa, shear fracture may occur locally, so that the pressure cannot be increased any more. That is to say, the existing seal connection structure between the capsule body interface and the external joint with pressure liquid can only reach several megapascals at most, the pressure rises, and the rubber at the capsule inlet can be locally extruded or sheared by the high-pressure metal gasket, so that local rupture occurs to cause loading failure, and therefore the core holder described in the patent still can not realize the loading requirement of three axial super loads in fact.

Chinese patent application 202010911726.6 discloses a rigid-flexible true triaxial grouting seepage coupling test device for CT scanning, the first main stress loading system and the second main stress loading system in the device are rigid loading systems, the third main stress loading system is a flexible system, although the patent adopts a composite loading mode of two-way rigid loading and one-way flexible loading, the problem of corner stress concentration caused by three-way stress loading is solved, however, because the patent only has one flexible loading direction, CT scanning and photographing can be realized only in one direction, a sample needs to be loaded to a certain load first, then all connected pipelines are removed, and the true triaxial experiment box can be placed into CT scanning equipment to carry out CT scanning in the direction, so that not only can the omni-directional scanning of a sample be realized, but also the loading force of several megapascals (4-7 megapascals disclosed in the specification) can be still realized.

In summary, no report of a large-load core holder and a true triaxial experimental device which can realize miniaturization and light weight, can realize independent super-load (up to dozens of megapascals, even hundreds of megapascals) loading in three axial directions and can be combined with CT scanning exists in the prior art.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a large-load core holder and a true triaxial experimental device which can realize miniaturization and light weight, can realize independent super-large load (up to dozens of megapascals, even hundreds of megapascals) loading in three axial directions and can be combined with CT scanning.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a can combine CT scanning's big load rock core holder, includes and passes power end, passes power end down and can be by the equal open-ended barrel in both ends of the X ray penetrable non-metallic material, is equipped with circumference pressure-bearing carbon fiber cover in the periphery of this barrel, is equipped with at least a pair of axial pressure-bearing carbon fiber ring at the outer axial symmetry of this barrel, is equipped with sample chamber and symmetric distribution in the cavity of this barrel and holds the chamber at 4 capsules of this sample chamber left and right, preceding, 4 backs sides, wherein: the two capsule bodies positioned in the left and right capsule accommodating cavities are used for X-direction flexible loading and force transmission, and the two capsule bodies positioned in the front and rear capsule accommodating cavities are used for Y-direction flexible loading and force transmission; each capsule body is provided with an inward-turned skirt edge interface, a sealing plug is connected in each inward-turned skirt edge interface in an interference fit manner, each sealing plug is provided with a liquid injection pipe communicated with the inner cavity of the capsule body in a penetrating manner, and all the liquid injection pipes penetrate out of the upper force transmission end head; and a Z-direction loading piston rod is arranged in the center of the lower force transmission end in a penetrating way.

In a preferable scheme, an elastic buffer gasket and a rigid bearing block are arranged at the top and the bottom of each capsule body.

In a preferred embodiment, an axially rigid pressure block is provided between the upper force-transmitting end and the end of the sample chamber.

According to the preferable scheme, the inward-turning skirt edge connector is an embedded cylindrical through hole, and the sealing plug is a metal cylinder.

In a further preferable scheme, one or more outer convex annular belts are arranged on the outer peripheral surface of the sealing plug.

In a preferable scheme, the force transmission surface of the capsule body is a plane or a curved surface.

The utility model provides an implementation scheme, the peripheral part of passing power end and the peripheral part of passing power end down at last all sets firmly at least one set of cantilever that becomes central symmetry, and forms mirror symmetry between last cantilever and the lower cantilever, all is equipped with axial pressure-bearing carbon fiber ring on every group upper and lower cantilever that constitutes mirror symmetry.

According to the optimal scheme, the upper arc end and the lower arc end of each axial pressure-bearing carbon fiber ring are respectively fixedly arranged in the opening of a U-shaped limiting seat, and the distance between the bottom surface of the upper U-shaped limiting seat and the top surface of the lower U-shaped limiting seat is matched with the distance between the top surface of the upper cantilever and the bottom surface of the lower cantilever, so that each axial pressure-bearing carbon fiber ring can be tensioned to the upper cantilever and can be conveniently assembled and disassembled.

Further preferred scheme, all detachably be connected with on every cantilever hug closely the spacing baffle who corresponds the spacing seat outside of U type.

According to a further preferred scheme, the upper limiting baffle attached to the outer side of the upper U-shaped limiting seat is detachably connected to the upper cantilever, the lower limiting baffle attached to the outer side of the lower U-shaped limiting seat is detachably connected to the lower cantilever, and the upper limiting baffle and the lower limiting baffle form a mirror symmetry relation.

A large-load true triaxial experimental device capable of combining CT scanning comprises the large-load rock core holder, a Z-direction loading cylinder, a Z-direction hydraulic loading system, an X-direction hydraulic loading system and a Y-direction hydraulic loading system, wherein the Z-direction loading cylinder is connected with a lower force transmission end head in a sealing manner, a piston is arranged in the Z-direction loading cylinder, a Z-direction loading piston rod is fixedly connected with the piston, a hydraulic conveying channel communicated with a piston cavity is arranged at the bottom of the Z-direction loading cylinder, the hydraulic conveying channel is connected with a Z-direction hydraulic loading system through a pressure-resistant hose, liquid injection pipes on two capsule bodies used for X-direction flexible loading and force transmission in the large-load core holder are connected with the X-direction hydraulic loading system through the pressure-resistant hose, and liquid injection pipes on two capsule bodies used for Y-direction flexible loading and force transmission in the large-load core holder are connected with a Y-direction hydraulic loading system through pressure-resistant hoses.

In one embodiment, the Z-direction loading cylinder is connected with the lower force transmission end head through a bidirectional nut.

In a preferred scheme, a buffering spacer is arranged between the force transmission surface of the capsule body and the force bearing surface of the sample.

In a further preferred scheme, the buffer spacer is made of a non-metal material.

Compared with the prior art, the invention has the following beneficial technical effects:

1. according to the large-load core holder, the circumferential pressure-bearing carbon fiber sleeve and the axial pressure-bearing carbon fiber ring are arranged outside the cylinder, and 4 capsule bodies are arranged on the left side, the right side, the front side and the rear side of the sample cavity, so that independent flexible loading in the X direction and the Y direction is realized, the penetration of CT scanning rays is not influenced, and the large-load core holder can be used in combination with CT scanning equipment;

2. the inward-turning skirt edge interface is creatively arranged on the capsule body, so that the shearing damage of the pressurized liquid to the rubber wall at the interface of the capsule body is skillfully avoided, the pressure resistance of the capsule body is not limited by the interface any more, and only depending on the crushing strength of the rubber material forming the capsule body, the loading requirement of ultrahigh hydraulic pressure up to dozens of megapascals or even hundreds of megapascals can be met by selecting the rubber material with the required crushing strength to manufacture the capsule body, so that the invention skillfully solves the difficult problem of large-load flexible loading, and the loading pressure of the capsule body can be remarkably improved by dozens of times or even hundreds of times (can be up to dozens of megapascals or even hundreds of megapascals) compared with the prior art (at most, only can realize several megapascals); experiments prove that the true triaxial experiment device formed by the large-load core holder provided by the invention can enable the flexible loading force in the X direction and the Y direction to be more than 100 MPa, and can realize the Z-direction loading force of more than 500 MPa because the Z direction is rigid loading, so that the true triaxial experiment device provided by the invention can completely meet the large-load simulation experiment requirement of the core in a true triaxial stress state, and has significant progress compared with the prior art;

3. because the core holder mainly adopts non-metal composite materials such as carbon fiber, engineering plastics and the like, and the core holder can realize the loading of three axial ultrahigh hydraulic pressures, the weight of the whole true triaxial experimental device can be reduced to one tenth of that of the traditional true triaxial experimental device under the condition of realizing the same hydraulic loading, for example: if the sample specification is 50 x 100mm, the weight of the true triaxial experimental device provided by the invention is only 50 kg; if the sample specification is 75 x 150mm, the weight of the true triaxial experimental device provided by the invention is about 100 kg; therefore, the invention can easily realize the light weight and miniaturization of the rock core holder and the true triaxial test device, and has important significance for realizing the combination of the true triaxial test device and the CT scanning technology;

in a word, compared with the prior art, the method not only produces unexpected technical effects, but also produces remarkable progress, and has important value in exploring the real dynamic physical property change of the rock sample in a true triaxial stress state.

Drawings

FIG. 1 is a schematic diagram of a prior art force-transferring capsule of the background art;

FIG. 2 is a schematic perspective view of a large load core holder that can be used in conjunction with CT scanning according to an embodiment of the present disclosure;

FIG. 3 is a longitudinal cross-sectional view of the high-load core holder shown in FIG. 2;

FIG. 4 is an enlarged view of a portion of FIG. 3;

FIG. 5 is a schematic structural diagram of a cartridge provided in an embodiment of the present invention;

figure 6 is a partial cross-sectional view of a capsule body provided by an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a capsule body provided by the embodiment of the invention after a sealing plug is installed;

FIG. 8 is a schematic view of the inverted skirt interface after injection of a pressurized liquid in accordance with an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a sealing plug according to an embodiment of the present invention;

FIG. 10 is a schematic view of the connection between the inverted skirt interface and the sealing plug in an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of an axially bearing carbon fiber ring provided by an embodiment of the invention;

FIG. 12 is a schematic cross-sectional view of an axial pressure-bearing carbon fiber ring provided by an embodiment of the invention;

FIG. 13 is a schematic structural view of a U-shaped position-limiting base according to an embodiment of the present invention;

FIG. 14 is a schematic structural view of an axially bearing carbon fiber ring provided by an embodiment of the present invention;

FIG. 15 is a schematic structural diagram of a true triaxial apparatus with a large load capable of combining with CT scanning according to an embodiment of the present invention;

fig. 16 is a schematic structural diagram of a true triaxial apparatus with a large load according to an embodiment of the present invention, when the apparatus is used in conjunction with CT scanning.

The numbers in the figures are as follows:

firstly, a capsule body; secondly, pressing the nut downwards; ③ lower gasket; fourthly, a liquid injection pipe; fifthly, mounting a gasket; sixthly, pressing the nut;

01. an upper force transmission end socket; 02. a lower force transfer end; 03. a barrel; 031. a sample chamber; 032a, left capsule accommodating chamber; 032b, right capsule accommodating chamber; 032c, an anterior capsule accommodating chamber; 032d, a posterior capsule accommodating cavity; 04. a circumferential pressure-bearing carbon fiber sleeve; 05. an axial pressure-bearing carbon fiber ring; 06. a capsule body; 06a, a left capsule body; 06b, a right capsule body; 061. an inverted skirt edge interface; 0611. the skirt edge is turned inwards; 062. a force transmission surface; 07. an elastic buffer pad; 08. a rigid bearing block; 09. an axial rigid pressing block; 010. a piston rod is loaded in the Z direction; 011. sealing the plug; 0111. an outer convex annular belt; 012. a liquid injection pipe; 012a, forming two liquid injection pipes on the capsule body which is flexibly loaded in the X direction; 012b, liquid injection pipes on the two capsule bodies which are flexibly loaded in the Y direction; 013. a cantilever; 013a, upper cantilever; 013b, lower cantilever; 014. a U-shaped limiting seat; 014 a; an upper U-shaped limiting seat; 014b, a lower U-shaped limiting seat; 015. a limit baffle; 015a, an upper limit baffle; 015b, a lower limit baffle;

1. a large-load core holder; 1-1, cylinder section; 2. a Z-direction loading cylinder; 21. a piston; 22. a hydraulic transfer passage; 3. a Z-direction hydraulic loading system; 4. an X-direction hydraulic loading system; 5. a Y-direction hydraulic loading system; 6. a two-way nut; 7. a CT rotating table; 8. a CT ray source; 9. a CT light sensing plate; 10. a sample; 101. a stress surface; 11. a buffer spacer.

Detailed Description

The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the terms "upper", "lower", "left", "right", "front", "back", "top" and "bottom" in the present application are defined in a relative manner, and the definitions in the embodiments are only for convenience of description or simplification, and the indicated relationships are not indicated or implied to be limited to the embodiments, so the present application is not limited thereto.

Examples

Please refer to fig. 2 to 5: the big load core holder 1 that this embodiment provided can combine CT scanning, including last biography power end 01, pass power end 02 down and can be by the equal open-ended barrel 03 in X ray's the both ends of the penetrable non-metallic material, be equipped with circumference pressure-bearing carbon fiber sleeve 04 in the periphery of this barrel 03, be equipped with at least a pair of axial pressure-bearing carbon fiber ring 05 at the outer axial symmetry of this barrel 03, be equipped with sample chamber 031 and symmetric distribution in the cavity of this barrel 03 the left side capsule of this sample chamber 031 and hold chamber 032a, the right side capsule that distributes on the right side holds chamber 032b, the front side capsule that distributes in the front side holds chamber 032c, the rear side capsule that distributes in the rear side holds chamber 032d, wherein: the left capsule body 06a in the left capsule housing cavity 032a and the right capsule body 06b in the right capsule housing cavity 032b are used for X-direction flexible loading force transfer, and the front capsule body (not shown in the figure) in the front capsule housing cavity 032c and the rear capsule body (not shown in the figure) in the rear capsule housing cavity 032d are used for Y-direction flexible loading force transfer; the top and the bottom of each capsule body 06 are respectively provided with an elastic buffer gasket 07 and a rigid pressure bearing block 08, and an axial rigid pressing block 09 is arranged between the upper force transmission end 01 and the end part of the sample cavity 031; in addition, a Z-direction loading piston rod 010 penetrates through the center of the lower force transmission end 02.

Please refer to fig. 3, fig. 4, fig. 6 and fig. 10: the capsule body 06 in this embodiment is provided with inward-turned skirt interfaces 061, and the inward-turned skirt interfaces 061 are preferably embedded cylindrical through holes; a sealing plug 011 is connected in each inward-turned skirt edge interface 061 in an interference manner (namely, the outer diameter of the sealing plug 011 is slightly larger than the inner diameter of the inward-turned skirt edge interface 061, so that the inward-turned skirt edge 0611 can be pre-deformed and can be coated on the outer peripheral surface of the sealing plug 011 with small force), a liquid injection pipe 012 communicated with the inner cavity of the capsule body 06 penetrates through each sealing plug 011, and all the liquid injection pipes 012 penetrate out of the force transmission end head 01.

Referring to fig. 7, 9 and 10, the sealing plug 011 of the present embodiment is preferably a metal cylinder, and one or more convex annular bands 0111 are preferably disposed on the outer circumferential surface of the sealing plug 011, so that a concave-convex joint surface is formed between the outer circumferential surface of the sealing plug 011 and the inward-turned skirt 0611, which is advantageous for ultra-high pressure sealing.

Referring to fig. 8 again, when the pressurized liquid enters the capsule body 06 through the liquid injection tube 012, the pressure of the pressurized liquid is applied to the inward-turned skirt 0611, so that the inward-turned skirt 0611 is more tightly pressed against the outer peripheral surface of the sealing plug 011, thereby achieving self-tightening sealing of the capsule body 06, and the larger the pressure p in the capsule body 06 is, the larger the pressure p of the inward-turned skirt 0611 against the outer peripheral surface of the sealing plug 011 is, and the better the sealing effect is.

The force-transmitting surface 062 of the capsule 06 may be flat (as shown in figures 3, 4, 6 and 10) to facilitate the force-transmitting loading of a cube-shaped test sample; but may also be curved to facilitate force loading of a cylindrical sample.

As shown in fig. 2 and fig. 11 to 14, at least one set of cantilevers 013 (3 sets are shown in the figures, but not limited thereto) with central symmetry are fixedly arranged on the outer circumferential portion of the upper force transfer tip 01 and the outer circumferential portion of the lower force transfer tip 02, the upper cantilevers 013a and the lower cantilevers 013b form mirror symmetry, and each set of upper and lower cantilevers with mirror symmetry is provided with an axial pressure-bearing carbon fiber ring 05.

At present, in the prior art, an upper force transmission end 01 and a lower force transmission end 02 are assembled with a cylinder body 03, and then an axial pressure-bearing carbon fiber ring 05 is manufactured, so that the problems of low operation efficiency and inconvenience in sample replacement exist in the assembly mode. To solve this problem, the present application provides an axially bearing carbon fiber ring 05 as shown in fig. 11, as can be seen in conjunction with fig. 11 and 12: the axial pressure-bearing carbon fiber ring 05 is characterized in that the upper arc end and the lower arc end of the axial pressure-bearing carbon fiber ring 05 are respectively fixedly arranged in the openings of the U-shaped limiting seats 014, the axial pressure-bearing carbon fiber ring 05 is obtained by winding carbon fibers on the two U-shaped limiting seats 014 and then performing thermosetting molding on the carbon fibers through resin.

Particularly, the distance between the bottom surface of the upper U-shaped limit seat 014a and the top surface of the lower U-shaped limit seat 014b is adapted to the distance between the top surface of the upper cantilever 013a and the bottom surface of the lower cantilever 013b, so that the upper cantilever and the lower cantilever can be tensioned by each axial pressure-bearing carbon fiber ring, the sample can be conveniently replaced and detached, and the operation is specifically realized as follows:

meanwhile, the bottom surface of the upper U-shaped limiting seat 014a positioned at the upper arc end of the axial pressure-bearing carbon fiber ring 05 is separated from the top surface of the upper cantilever 013a, the top surface of the lower U-shaped limiting seat 014b positioned at the lower arc end of the axial pressure-bearing carbon fiber ring 05 is separated from the bottom surface of the lower cantilever 013b, so that the axial pressure-bearing carbon fiber ring 05 can be conveniently disassembled and taken down (please refer to fig. 14), and when all the axial pressure-bearing carbon fiber rings 05 are disassembled and taken down, the upper force transmission end head 01 and the lower force transmission end head 02 can be separated from the cylinder body 03, so that the sample in the cylinder body 03 can be replaced;

conversely, the bottom surface of the upper U-shaped stopper 014a located at the upper arc end of the axial pressure-bearing carbon fiber ring 05 is abutted against the top surface of the upper cantilever 013a, and the top surface of the lower U-shaped stopper 014b located at the lower arc end of the axial pressure-bearing carbon fiber ring 05 is abutted against the bottom surface of the lower cantilever 013b, so that the axial pressure-bearing carbon fiber ring 05 can be mounted on the upper cantilever 013a and the lower cantilever 013b (see fig. 14); after all the axial pressure-bearing carbon fiber rings 05 are installed, the upper force transmission end head 01 and the lower force transmission end head 02 can be fixedly connected with the cylinder body 03.

In order to avoid axial pressure-bearing carbon fiber ring 05 to produce the not hard up problem of sliding of emergence because of taking place deformation and leading to being connected with the cantilever, this application all detachable be connected with on every cantilever 013 hug closely at the limit baffle 015 that corresponds the spacing seat 014 outside of U type, and the concrete implementation mode is: an upper limiting baffle 015a tightly attached to the outer side of the upper U-shaped limiting seat 014a is detachably connected (in this embodiment, connected by screws) to each upper cantilever 013a, a lower limiting baffle 015b tightly attached to the outer side of the lower U-shaped limiting seat 014b is detachably connected (in this embodiment, connected by screws) to each lower cantilever 013b (see fig. 2), and the upper cantilever 013a and the lower cantilever 013b, the upper U-shaped limiting seat 014a and the lower U-shaped limiting seat 014b, and the upper limiting baffle 015a and the lower limiting baffle 015b all form a mirror symmetry relationship; when the axial pressure-bearing carbon fiber ring 05 needs to be disassembled, the fixing screws are firstly unscrewed, so that the corresponding upper and lower limiting baffles 015a and 015b rotate by 180 degrees, and the blocking effect of the limiting baffles on the corresponding axial pressure-bearing carbon fiber ring 05 can be cancelled (please refer to fig. 2 and 14).

Fig. 15 is a schematic structural diagram of a high-load true triaxial experimental apparatus capable of combining with CT scanning according to an embodiment of the present invention, and it can be seen from fig. 15 that:

the large-load true triaxial experimental device capable of combining CT scanning comprises the large-load rock core holder 1, a Z-direction loading cylinder 2, a Z-direction hydraulic loading system 3, an X-direction hydraulic loading system 4 and a Y-direction hydraulic loading system 5, wherein the Z-direction loading cylinder 2 is in sealing connection with a lower force transmission end 02, a piston 21 is arranged in the Z-direction loading cylinder 2, a Z-direction loading piston rod 010 is fixedly connected with the piston 21, a hydraulic conveying channel 22 communicated with the piston cavity is arranged at the bottom of the Z-direction loading cylinder 2, the hydraulic conveying channel 22 is connected with the Z-direction hydraulic loading system 3 through a pressure-resistant hose, liquid injection pipes 012a on two capsule bodies forming X-direction flexible loading are connected with the X-direction hydraulic loading system 4 through the pressure-resistant hose, and liquid injection pipes 012b on two capsule bodies forming Y-direction flexible loading are connected with the Y-direction hydraulic loading system 5 through the pressure-resistant hose; in this embodiment, the Z-direction loading cylinder 2 is connected to the lower force transmission end 02 through a bidirectional nut 6.

It should be noted that, in the present application, an inward-turned skirt interface 061 is provided on each capsule body 06, and one or two liquid injection pipes 012 are arranged on the sealing plug 011 in each inward-turned skirt interface 061 in a penetrating manner; two inward-turning skirt connectors 061 can be arranged on each capsule body 06, and a liquid injection pipe 012 penetrates through the sealing plug 011 in each inward-turning skirt connector 061; when 2 liquid injection pipes are arranged on the capsule body 06, the liquid in the capsule body 06 can circulate one by one, so that the purpose of heating or cooling while loading the sample is realized.

Fig. 16 shows a manner of using the large-load true triaxial experimental apparatus provided in this embodiment in combination with CT scanning, that is:

during use, the large-load true triaxial experimental device provided by the application is placed on the CT rotating table 7, and the position of the CT ray source 8 can horizontally penetrate through the cylinder section 1-1 of the large-load core holder 1 to reach the CT photosensitive plate 9.

Because the cylinder section 1-1 of the large-load core holder 1 provided by the application is mainly made of non-metal composite materials such as carbon fiber, engineering plastics and the like, and the core holder can respectively realize three axial ultrahigh hydraulic loads, the weight of the whole true triaxial experimental device can be reduced to one tenth of that of the traditional true triaxial experimental device under the condition of realizing the same hydraulic load, for example: if the sample specification is 50 x 100mm, the weight of the true triaxial experimental device provided by the invention is only 50 kg; if the sample specification is 75 x 150mm, the weight of the true triaxial experimental device provided by the invention is about 100 kg; therefore, the rock core holder and the true triaxial test device provided by the invention have the advantages of light weight and miniaturization, the combination of the true triaxial test device and CT scanning is easily realized, and the 360-degree CT scanning (sample rotation or CT rotation) can be realized at any time or position under the condition of true triaxial stress.

In addition, as the stress surface of the test sample 10 may be partially uneven or cracked, the buffer spacer 11 is arranged between the force transmission surface 062 of the capsule body 06 and the corresponding stress surface 101 of the test sample 10 (see fig. 15 and 16) in the application, so as to avoid the local damage of the capsule body caused by the local shape irregularity or crack of the test sample; the buffer spacer 11 is preferably made of a non-metallic material to avoid affecting the penetration of X-rays, which would make it impossible to use it in conjunction with CT scanning.

It is finally necessary to point out here: the above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.