Large scale triaxial shear test on spherical particle coarse aggregate is carried out.
采用大型三轴仪对球形颗粒散粒体进行了应变式三轴试验。
The dynamic triaxial shear test on the dynamic properties of the Xiaolangdi in situ siltized intercalations within core samples is performed.
对黄河小浪底工程左岸山体含泥化夹层的岩芯试样进行了动三轴试验研究。
In order to study the correlation between shear wave velocity of soils and their triaxial shear test mechanics index, a new transducer is developed on the basis of torsion vibration principle.
为了研究土的剪切波速与其三轴剪切试验力学指标之间的关系，依据扭剪振动原理，开发出一种测试三轴压力室内土样剪切波速的传感器。
The stress-strain relation of undisturbed loess during triaxial shear test is studied by using real-time computerized tomography (CT) scanning.
采用三轴CT实时试验对原状黄土在三轴剪切试验过程中的应力-应变进行了研究。
The steady state strength concepts, the consolidated-undrained triaxial shear test method and the test results are introduced.
介绍了稳态强度理论的基本概念、稳态强度的固结不排水剪切试验方法及试验结果；
The stress-strain curves of two kinds of reinforced expansive soil with different water contents around optimal value are obtained by triaxial shear test on reinforced soils.
通过室内加筋三轴剪切试验，得出最优含水率附近两种不同含水率的加筋膨胀土的应力-应变关系曲线。
The relation of strain and stress , the shear resistance character and the law of parameter out of shape which has been gotten through the triaxial shear test .
通过室内三轴试验研究分析了爆破料的应力应变关系，抗剪强度特性，变形参数的变化规律；
This paper mainly studies the strength softening characteristic of loess-like soil by triaxial shear test on the basis of primary research productions of loess.
本文在黄土已有研究成果的基础上，通过三轴剪切试验对类黄土（黄土状土）的强度软化特性进行了重点研究。
This paper mainly studies the strength softening characteristic of clay by triaxial shear test on the basis of primary research productions of loess.
本文通过三轴剪切试验对一般粘性土的强度、变形特性进行了重点研究。
The stress-strain relationship depends on the combinational style of net normal stress and matric suction, and suction enhances the stress-strain stiffness feature during triaxial shear test.
在剪切试验中，非饱和黏土应力应变关系依赖于净围压和基质吸力的不同组合，基质吸力增强土体应力–应变关系的硬化特性；
Triaxial shear test, of which can do CT scanning at the same time, is conducted to the undisturbed subgrade loess. The change of microstructure of loess is analyzed from CT numbers and CT images.
利用可同步进行CT扫描的三轴仪，对路基原状黄土进行了三轴剪切试验，从CT数和CT图像两方面分析了不同受力过程中黄土细观结构的变化。
The study covers the following main items: (1) the shear strength parameter triaxial test and study of the deposit body;
主要研究内容为：（1）堆积体抗剪强度参数三轴试验研究；
Parameters of shear strength from triaxial compression test are widely used in project construction.
在工程建设中三轴压缩试验提供的土体抗剪强度参数得到越来越广泛的应用。
A method for testing the interaction between soil and shaft wall by high pressure direct shear apparatus and triaxial servo test system has been presented.
介绍了用高压直剪仪和三轴伺服仪测定大埋深土与井壁相互作用试验方法，得到了土与井壁相互作用剪应力-位移曲线、单位刚度系数和强度等参数。
It is result from the different failure modes of soil of direct shear test and triaxial compression test:In direct shear test, the shear plane is inherent;
分析认为该现象是由于直剪试验和三轴压缩试验中土的破坏模式不同所致：直剪试验的剪切面固定；
Comparison of contrast between direct box shear test and triaxial test;
用离散单元法模拟了粒状体的直剪试验。
On the large-scale triaxial test equipment, 3D shear test of polymer geogrid reinforced crushed gravel soil and non-reinforced soil were carried out.
在大型三轴仪上进行了素碎石土和加筋碎石土的三轴排水剪切试验，探讨了加筋碎石土的强度及变形特性；
The resistance to shear by the direct shear test and the triaxial compression test in soil test is compared and analyzed. The different test method is adopted about the different work.
对土工试验中直接剪切试验与三轴压缩试验所得的抗剪强度进行了比较与分析，从而对工程不同要求提出不同的试验方法。
In the paper we use the shear strength parameter of triaxial compression test under the starting water content to correct the direct shear strength parameter.
利用启动含水率下的三轴试验参数对直剪试验参数进行了修正。
This paper introduces the results of unconfined compression test, direct shear test and unconsolidated undrained triaxial test for saturated clay at a site in shanghai.
本文介绍了上海菜工程地基饱和粘土的无侧限试验、直剪试验及三轴不固结不排水试验的结果。
Shear strength index of direct shear test is larger than triaxial compression test.
在密实度较小、反复剪切时，抗剪强度指标没有明显改变；
A new variety of cement-stabilized soil with additive was studied by consolidated undrained triaxial test(CU test), direct shear test and compression test.
通过三轴试验、直剪试验和压缩试验，对一种掺有添加剂的新型水泥固化土进行了研究。
The cyclic triaxial test and resonant column test with in situ shear wave velocity control the sample was conducted for the sand of Pubugou dam foundation.
以原位剪切波速值作为制样控制标准，进行了坝基砂的动力特性研究和坝基上、下游砂层的液化可能性分析。
Dynamic triaxial test is mainly used to determine the dynamic shear modulus & dynamic damping ratio of soil, which are the important parameters for seismic response analysis.
动三轴试验主要确定土的动剪切模量和土的动阻尼比，而这些参数又是地震动反应分析中的重要参数，该参数的取值小直接影响了桥梁的勘察设计。
I have a chance to use the equipment of triaxial test which import from England and to carry on research shear strength of asphalt mixture.
本文有机会借助英国进口的三轴剪切试验设备，对沥青混合料的抗剪性能采用三轴剪切试验进行深入研究。
The volumetric strain induced by shear stress is shrinking at first, then dilating later under triaxial compression test conditions, of which the value is determined by density and stress state.
三轴压缩试验条件下，剪应力引起的体积变形一般是先剪缩后剪胀的，其大小由密度和应力状态决定。
The test results show that the shear strength of soils after lateral unloading are different from that of conventional triaxial test.
试验结果表明，经过侧向卸荷过程土样的抗剪强度指标与常规三轴试验明显不同。
In order to compare different shear strength equations of unsaturated soil, Luojiashan soil samples are selected for the soil-water characteristic curve(SWCC) test and unsaturated triaxial tests.
通过珞珈山土样的土–水特征曲线试验和非饱和三轴剪切试验对非饱和土强度公式进行比较研究。
In order to compare different shear strength equations of unsaturated soil, Luojiashan soil samples are selected for the soil-water characteristic curve(SWCC) test and unsaturated triaxial tests.
通过珞珈山土样的土–水特征曲线试验和非饱和三轴剪切试验对非饱和土强度公式进行比较研究。
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感谢您的反馈，我们会尽快进行适当修改！Rock sample fixing device with three-jaw chuck for cyclic tension and compression test
Document Type and Number:
United States Patent 9500574
A rock sample fixing device with a three-jaw chuck for cyclic tension and compression testing including: a lower clam the lower clamp including a lower connector connected to a loading base at a bottom of a testing machine, a lower end cap for fixing samples, a lower chain connecting the lower connector and the lower end cap, a first central position-limit mechanism, a second central position-limit mechanism, and a first the upper clamp including an upper connector connected to a loading base at a top of the testing machine, an upper end cap for fixing samples, an upper chain connecting the upper connector and the upper end cap, a third central position-limit mechanism, a fourth central position-limit mechanism, and a second hydraulic mechanism.
Inventors:
Liu, Jianfeng (Chengdu, CN)
Ju, Yang (Chengdu, CN)
Pei, Jianliang (Chengdu, CN)
Xu, Huining (Chengdu, CN)
Wang, Lu (Chengdu, CN)
Xu, Yangmengdi (Chengdu, CN)
Zou, Hang (Chengdu, CN)
Application Number:
Publication Date:
11/22/2016
Filing Date:
02/04/2016
View Patent Images:
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Export Citation:
Sichuan University (Chengdu, CN)
International Classes:
Field of Search:
73/826, 73/788, 73/796, 73/806, 73/760, 73/862
US Patent References:
Olsen166/308.1Xu73/8314431202Swenson279/106
Primary Examiner:
Caputo, Lisa
Assistant Examiner:
Plumb, Nigel
Attorney, Agent or Firm:
Matthias Scholl, PC
Scholl, Matthias
The invention claimed is:
A rock sample fixing device with a three-jaw chuck for cyclic tension and compression testing, the device comprising: the lower clamp comprising: a lower connector connected to a loading base at a bottom of a testing machine, a lower end cap for fixing samples comprising a first sample fixing groove and a first connection segment, a lower chain connecting the lower connector and the lower end cap, a first central position-limit mechanism, a second central position-limit mechanism, and a first the upper clamp comprising: an upper connector connected to a loading base at a top of the testing machine, an upper end cap for fixing samples comprising a second sample fixing groove and a second connection segment, an upper chain connecting the upper connector and the upper end cap, a third central position-limit mechanism, a fourth central position-limit mechanism, and a second wherein the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism have the same structure and all comprise a three-jaw chuck, a support an one end of the support is connected to
and another end of the support is connected to the first hydraulic mechanism and the second hydraulic mechanism have the same structure, which both comprise a circular piston and a circular oil cylinder assembled with the first central position-limit mechanism and the loading base at the bottom of the testing m the three-jaw chuck in the first central position-limit mechanism contacts the loading base at the bottom of the lower connector is arranged in a center hole of the three- free ends of three claws of the three jaw chuck in the first central position-limit mechanism contact the external side of the lower co the second central position-limit mechanism and the lower e the three-jaw chuck in the second central position-limit mechanism contacts an outer bottom wall of the first sample fixing groove
the first connection segment of the lower end cap is arranged in the center hole of the three- free ends of three claws of the three-jaw chuck in the second central position-limit mechanism contact an external side
the first hydraulic mechanism is arranged between the first central position-limit mechanism and the second central position- the circular oil cylinder of the first hydraulic mechanism is connected to the connecting board of the first central position-limit mechanism and the circular piston of the first hydraulic mechanism is connected to the connecting board of the second central position- or, the circular oil cylinder of the first hydraulic mechanism is connected to the connecting board of the second central position-limit mechanism and the circular piston of the first hydraulic mechanism is connected to the connecting board of the first central position- the lower chain is arranged in a space enclosed by the first central position-limit mechanism, the first hydraulic mechanism and the second central position- the third central position-limit mechanism and the upper e the three jaw chuck in the third central position-limit mechanism contacts the outer bottom wall of the second sample fixing groove
the second connection segment of the upper end cap is arranged in the center hole of the three- free ends of three claws of the three-jaw chuck in the third central position-limit mechanism contact the external side of the second connection segment of the upper
the fourth central position-limit mechanism and the loading base at the top of the testing m the three-jaw chuck in the fourth central position-limit mechanism contacts the loading base at the top of the upper connector is arranged in the center hole of the three- free ends of three claws of the three jaw chuck in the fourth central position-limit mechanism contact the outer side of the second hydraulic mechanism is arranged between the third central position-limit mechanism and the fourth central position- the circular oil cylinder of the second hydraulic mechanism is connected to the connecting board of the third central position-limit mechanism and the circular piston of the second hydraulic mechanism is connected to the connecting board of the fourth central position- or, the circular oil cylinder of the second hydraulic mechanism is connected to the connecting board of the fourth central position-limit mechanism and the circular piston of the second hydraulic mechanism is connected to the connecting board of the third central position- the upper chain is arranged in a space enclosed by the third central position-limit mechanism, the second hydraulic mechanism and the fourth central position-limit mechanism.
The device of claim 1, wherein the supports in the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism are four round rods, the connecting board is a circular board, and the four round rods are all arranged on the three jaw chuck and a circular surface of the connecting board.
The device of claim 1, wherein the supports in the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism are two board bodies with a circular arc cross section, the connecting board is a circular board, the two board bodies are arranged on the three-jaw chuck and a circular surface of the connecting board symmetrically.
Description:
CROSS-REFERENCE TO RELATED APPLICATIONSPursuant to 35 U.S.C. §119 and the Paris Convention Treaty, this application claims the foreign priority benefit of Chinese Patent Application No. .3 filed Feb. 9, 2015, the contents of which, are incorporated herein by reference. Inquiries from the public to applicants or assignees concerning this document or the related applications should be directed to: Matthias Scholl PC., Attn.: Dr. Matthias Scholl Esq., 245 First Street, 18th Floor, and Cambridge, Mass. 02142.BACKGROUND OF THE INVENTIONField of the InventionThe invention relates to a device used for conducting mechanical property tests on fragile materials, in particular to a device fixing rock samples in direct cyclic tension and compression tests for a testing machine.Description of the Related ArtDue to structural limits of a sample fixing device, only a unidirectional compression test or a unidirectional tension measurement can be conducted in a rock test.The unidirectional tension test still has the following shortcomings: (1) test resu (2) it is easy to damage rock samples and not conducive to the test of the mechanical effect after r and (3) it is not easy to operate and the labor intensity is relatively high.In a unidirectional compression test, samples can only bear compression load but can't bear direct tension load. Therefore, a cyclic alternate compression and tension load test can't be conducted.SUMMARY OF THE INVENTIONIn view of the above-described problems, it is one objective of the invention to provide a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests so as to conduct cyclic alternate tension and compression load tests on rock samples, and ensure that the center line of the rock sample fixing device and the center line of the testing machine coincide in tests and the loading rigidity of the two sample ends is the same, which makes the connection of chains and end caps become easy, labor-saving and efficient.To achieve the above objective, in accordance with one embodiment of the invention, there is provided a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests comprising a lower clamp and an upper clamp: the lower clamp consists of a lower connector connected to the loading base at the bottom of the testing machine, a lower end cap for fixing samples, a lower chain connecting the lower connector and the lower end cap, a first central position-limit mechanism, a second central position-limit mechanism and a first hydraulic mechanism, and the lower end cap consists of a first sample fixing groove and a firs and the upper clamp consists of an upper connector connected to the loading base at the top of the testing machine, an upper end cap for fixing samples, an upper chain connecting the upper connector and the upper end cap, a third central position-limit mechanism, a fourth central position-limit mechanism and a second hydraulic mechanism, and the upper end cap consists of a second sample fixing groove and a secon the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism have the same structure and all consist of a three jaw chuck, a support an One end of the support is connected to
and another end of the support is connected to the three jaw chuck. The first hydraulic mechanism and the second hydraulic mechanism have the same structure, which both comprise a circular piston and a circular oil cylinder assembled with the circular piston. The first central position-limit mechanism and the loading base at the bottom of the testing machine are assembled. The three-jaw chuck in the first central position-limit mechanism contacts the loading base at the bottom of the testing machine. The lower connector is arranged in the center hole of the three-jaw chuck. Free ends of three claws of the three-jaw chuck in the first central position-limit mechanism contact the external side of the lower connector respectively. The second central position-limit mechanism and the lower end cap are assembled. The three-jaw chuck in the second central position-limit mechanism contacts the outer bottom wall of the first sample fixing groove of the lower end cap. The first connection segment of the lower end cap is arranged in the center hole of the three jaw chuck. Free ends of three claws of the three-jaw chuck in the second central position-limit mechanism contact the external side of the lower end cap. The first hydraulic mechanism is arranged between the first central position-limit mechanism and the second central position-limit mechanism. The circular oil cylinder of the first hydraulic mechanism is connected to the connecting board of the first central position-limit mechanism and the circular piston of the first hydraulic mechanism is connected to the connecting board of the second central position- or, the circular oil cylinder of the first hydraulic mechanism is connected to the connecting board of the second central position-limit mechanism and the circular piston of the first hydraulic mechanism is connected to the connecting board of the first central position-limit mechanism. The lower chain is arranged in the space enclosed by the first central position-limit mechanism, the first hydraulic mechanism and the second central position-limit mechanism. The third central position-limit mechanism and the upper end cap are assembled. The three-jaw chuck in the third central position-limit mechanism contacts the outer bottom wall of the second sample fixing groove of the upper end cap. The second connection segment of the upper end cap is arranged in the center hole of the three jaw chuck. Free ends of three claws in the three-jaw chuck in the third central position-limit mechanism contact the external side of the second connection segment of the upper end cap respectively. The fourth central position-limit mechanism and the loading base at the top of the testing machine are assembled. The three jaw chuck in the fourth central position-limit mechanism contacts the loading base at the top of the testing machine. The upper connector is arranged in the center hole of the three jaw chuck. Free ends of three claws of the three jaw chuck in the fourth central position-limit mechanism contact the outer side of the upper connector. The second hydraulic mechanism is arranged between the third central position-limit mechanism and the fourth central position-limit mechanism. The circular oil cylinder of the second hydraulic mechanism is connected to the connecting board of the third central position-limit mechanism and the circular piston of the second hydraulic mechanism is connected to the connecting board of the fourth central position- or, the circular oil cylinder of the second hydraulic mechanism is connected to the connecting board of the fourth central position-limit mechanism and the circular piston of the second hydraulic mechanism is connected to the connecting board of the third central position-limit mechanism. The upper chain is arranged in the space enclosed by the third central position-limit mechanism, the second hydraulic mechanism and the fourth central position-limit mechanism.In a class of this embodiment, the supports in the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism are four round rods, the connecting board is a circular board, and the four round rods are all arranged on the three jaw chuck and the circular surface of
or, the supports in the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism are two board bodies with a circular arc cross section, the connecting board is a circular board, the two board bodies are arranged on the three-jaw chuck and the circular surface of the connecting board symmetrically.In a class of this embodiment, the three-jaw chuck is selected from a manual chuck, a pneumatic chuck, or a hydraulic chuck.Compared with existing technologies, advantages of the rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests are as follows:1. Hydraulic mechanisms are arranged on the rock sample fixing device hereof to replace compression spiral springs. Since the pressure and rigidity provided by hydraulic mechanisms are much higher than the pressure and rigidity provided by spiral springs, the invention can conduct cyclic alternate tension and compression load tests on rock samples and has overcome the shortcoming that only a unidirectional compression or tension test can be conducted in current rock tests, and improved the combined test method for conducting cyclic alternate direct tension and compression load tests on unidirectional loading rock samples.2. Since two central position-limit mechanisms and one hydraulic mechanism are arranged on both the lower clamp and the upper clamp of the rock sample fixing device hereof, the invention can not only ensure that the loading rigidity at both ends of a sample in a test are consistent but also test the mechanical effect after rock test peak stress more effectively. Through the three-jaw chuck in the central position-limit mechanisms of the lower clamp and the upper clamp, the invention can ensure that the center line of the rock sample fixing device and the center line of the testing machine coincide in the test, avoid the occurrence of additional eccentric force and be conducive to improvement of accuracy of test results.3. Since the supports of the first central position-limit mechanism, the second central position-limit mechanism, the third central position-limit mechanism and the fourth central position-limit mechanism are four round rods or two board bodies with a circular arc cross section, it is easy to insert the supports into connector bolts, and install and dismantle the supports when the chains are connected to the end caps. And, at the same time, it is conducive to protecting the integrity of rock samples with low tensile strength before a test so as to improve the success rate of the test.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic diagram of a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests in accordance with one embodimFIG. 2 is a schematic diagram of a three-jaw chuck in accordance with one embodimFIG. 3 is a first schematic diagram of a first central position-limit mechanism or a second central position-limit mechanism or a third central position-limit mechanism or a fourth central position-limit mechanism in a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests (supports are round rods) in accordance with one embodimFIG. 4 is a top view of a central position-limit mechanism of a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests in FIG. 3 in accordance with one embodimFIG. 5 is a second schematic diagram of a first central position-limit mechanism or a second central position-limit mechanism or a third central position-limit mechanism or a fourth central position-limit mechanism in a rock sample fixing device with a three jaw chuck for cyclic tension and compression tests (the supports are arc board bodies) in accordance with one embodimFIG. 6 is a top view of a central position-limit mechanism of a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests in FIG. 5 in accordance with one embodimFIG. 7 is a schematic diagram of a first hydraulic mechanism in a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests or the second hydraulic mechanism in accordance with one embodim andFIG. 8 is top view of a first hydraulic mechanism and a second hydraulic mechanism in FIG. 7 in accordance with one embodiment of the invention.In figures, the following reference numbers are used: 1. Loading base at a bottom
2. Three- 2-1. F 2-2. S 2-3. C 2-4. S 2-5. L 2-5-1. P 2-5-2. B 3. L 4. S 5. C 6. L 7. L 8. L 9. R 10. U 11. U 12. U 13. U 14. Loading base at a top of 15. C 16. C 17. Piston position- 18. S 19. O 20. C 21. P 100. First central position- 200. Second central position- 300. Third central position- and 400. Fourth central position-limit mechanism.DETAILED DESCRIPTION OF THE EMBODIMENTSFor further illustrating the invention, experiments detailing a rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests are described below. It should be noted that the following examples are intended to describe and not to limit the invention.In the embodiment, the rock sample fixing device with a three-jaw chuck for cyclic tension and compression tests consists of a lower clamp and an upper clamp as shown in the FIG. 1. The lower clamp consists of a lower connector 3 connected to the loading base 1 at the bottom of the testing machine, a lower end cap 8 for fixing samples, a lower chain 6 connecting the lower connector and the lower end cap, a first central position-limit mechanism 100, a second central position-limit mechanism 200 and a first hydraulic mechanism, and the lower end cap 8 consists of a first sample fixing groove and a firs and the upper clamp consists of an upper connector 13 connected to the loading base 14 at the top of the testing machine, an upper end cap 10 for fixing samples, an upper chain 12 connecting with the upper connector and the upper end cap, a third central position-limit mechanism 300, a fourth central position-limit mechanism 400 and a second hydraulic mechanism, and the upper end cap 10 consists of a second sample fixing groove and a second connection segment.The first central position-limit mechanism 100, the second central position-limit mechanism 200, the third central position-limit mechanism 300 and the fourth central position-limit mechanism 400 have the same structure and all consist of a three-jaw chuck 2, a support 4 and a connecting board 5 as shown in FIGS. 3-4. As shown in FIG. 2, the three jaw chuck 2 is a manual chuck, and comprises a first jaw chuck 2-1, a second jaw chuck 2-2, three claws 2-3, a small bevel gear 2-4, and a large bevel gear 2-5. The first jaw chuck 2-1 and the second jaw chuck 2-2 are circular chucks, whose center hole diameters are the same. One side of the large bevel gear 2-5 is the bevel teeth 2-5-2 engaging with
the plane threads 2-5-1 are arranged on the other side the threads matching the plane threads 2-5-1 are arranged on the three claws 2-3. After assembly, the small bevel gear 2-4 and the large bevel gear 2-5 are arranged in the space enclosed by the first jaw chuck 2-1 and the second jaw chuck 2-2. The three claws 2-3 are respectively arranged in three guide grooves which are distributed with an angle of 120° in the claw chuck 2-1; and the threads of the claws engage with the plane threads 2-5-1 of the large bevel gear. The supports 4 are four round rods. The connecting board 5 is a circular board, whose center hole diameter are identical with the center hole diameter of the first jaw chuck 2-1 and the second jaw chuck 2-2. The four round rods are all arranged on the first jaw chuck 2-1 and the circular surface of the connecting board 5; and one ends of the round rods are connected to the first jaw chuck 2-1.As shown in FIGS. 6-7, the first hydraulic mechanism and the second hydraulic mechanism both comprise a circular piston 15, a circular oil cylinder 16, a piston position-limit ring 17 and sealing washers 18. One end of the circular piston 15 is inserted into and arranged in the circular cavity of the circular oil cylinder 16. An oil pipe 19 connected to the cavity is arranged at the closed end of the circular cavity of the circular oil cylinder 16. A control valve 20 and a pressure gauge 21 are arranged on the oil pipe 19. The piston position-limit ring 17 is arranged on the open end of the circular cavity of the circular oil cylinder 16. The sealing washers 18 are arranged on one end of the circular cavity inserted into the circular piston 15 and on the piston position-limit ring 17.The assembly method of each member or component of the lower clamp: the first central position-limit mechanism 100 and the loading base 1 at the bottom of the testing machine are assembled. The second jaw chuck 2-2 of the three jaw chuck in the first central position-limit mechanism 100 contacts the loading base 1. The lower connector 3 is arranged in the center holes of the first jaw chuck 2-1 and the second jaw chuck 2-2. Free ends of three claws of the three-jaw chuck in the first central position-limit mechanism 100 contact the external side of the lower connector 3 respectively. The second central position-limit mechanism 200 and the lower end cap 8 are assembled. The second jaw chuck 2-2 of the three-jaw chuck in the second central position-limit mechanism 200 contacts the outer bottom wall of the first sample fixing groove of the lower end cap 8. The first connection segment of the lower end cap 8 is arranged in the center holes of the first jaw chuck 2-1 and the second jaw chuck 2-2. Free ends of three claws of the three-jaw chuck in the second central position-limit mechanism 200 contact the external side of the lower end cap. The first hydraulic mechanism is arranged between the first central position-limit mechanism 100 and the second central position-limit mechanism 200. The circular oil cylinder 16 of the first hydraulic mechanism is connected to the connecting board 5 of the first central position-limit mechanism 100 and the circular piston 15 of the first hydraulic mechanism is connected to the connecting board 5 of the second central position-limit mechanism 200. The lower end of the lower chain 6 is connected to the lower connector 3 arranged on the loading base 1 at the bottom of and a dismountable connection between the upper end of the lower chain and the lower end cap is formed by the bolt 7. The lower chain 6 is arranged in the space enclosed by the first central position-limit mechanism 100, the first hydraulic mechanism and the second central position-limit mechanism 200.The assembly method of each member or component of the upper clamp: the third central position-limit mechanism 300 and the upper end cap 10 are assembled. The second jaw chuck 2-2 of the three jaw chuck in the third central position-limit mechanism 300 contacts the outer bottom wall of the second sample fixing groove of the upper end cap 10. The second connection segment of the upper end cap 10 is arranged in the center holes of the first jaw chuck 2-1 and the second jaw chuck 2-2. Free ends of three claws of the three jaw chuck in the third central position-limit mechanism 300 respectively contact the external side of the second connection segment of the upper end cap. The fourth central position-limit mechanism 400 and the loading base 14 at the top of the testing machine are assembled. The second jaw chuck 2-2 of the three-jaw chuck in the fourth central position-limit mechanism 400 contacts the loading base 14 at the top of the testing machine. The upper connector 13 is arranged in the center holes of the first jaw chuck 2-1 and the second jaw chuck 2-2. Free ends of three claws of the three jaw chuck in the fourth central position-limit mechanism 400 respectively contact the outer side of the upper connector 13. The second hydraulic mechanism is arranged between the third central position-limit mechanism 300 and the fourth central position-limit mechanism 400. The circular oil cylinder 16 of the second hydraulic mechanism is connected to the connecting board 5 of the third central position-limit mechanism 300 and the circular piston 15 of the second hydraulic mechanism is connected to the connecting board 5 of the fourth central position-limit mechanism 400. The upper end of the upper chain 12 is connected to the upper connector 13 arranged on the loading base 14 at the top of a dismountable connection between the lower end of the upper chain and the upper end cap is formed by the bolt 11. The upper chain 12 is arranged in the space enclosed by the third central position-limit mechanism 300, the second hydraulic mechanism and the fourth central position-limit mechanism 400.The rock sample 9 is arranged as shown in the FIG. 1. Both ends of the rock sample are connected to the second sample fixing grooves of the upper end cap 10 and the lower end cap 8 by high-strength adhesive.The invention is not limited to the embodiment. For example, the first central position-limit mechanism 100, the second central position-limit mechanism 200, the third central position-limit mechanism 300 and the fourth central position-limit mechanism 400 can also have the structure shown in FIGS. 5-6. That is, the supports 4 are two board bodies with a circul the connecting board 5 is
the two board bodies are arranged on the first jaw chuck 2-1 and the circular surface of the connecting board 5 one ends of the two board bodies are connected to the connecting board 5; the other ends of the two board bodies are connected to the first jaw chuck 2-1. The three-jaw chuck could also be a pneumatic chuck, or a hydraulic chuck.While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.
& 2004-. All rights reserved.