Rock tensile tester provided with automatic rectification devices

Abstract

The invention provides a rock tensile tester provided with automatic rectification devices. The rock tensile tester adopts an upper-lower symmetrical structure and comprises an upper tensile unit and a lower tensile unit, each of the upper tensile unit and the lower tensile unit comprises a clamping part, the automatic rectification device and a rock sample fixing part which are connected in the axial direction of a rock sample; each automatic rectification device comprises an upper connecting part, a cubic core and a lower connecting part which are sequentially mounted in the axial direction of the rock sample, two symmetrically distributed support lugs are arranged on each of the opposite surfaces of the upper connecting part and the lower connecting part, the four support lugs are hinged with four side surfaces of the cubic core through hinged pins, and the two support lugs located at the same connecting part are hinged with two opposite side surfaces of the cubic core; annular grooves are formed in each clamping part; a bonding groove is formed in an end of each rock fixing part. The tensile devices can be in a perpendicularly aligned tensile stress state all along after the rock tensile tester is stressed according to a force resolution principle, and the problem of eccentric ensile stress is solved very well.

Description

technical field [0001] The invention relates to a rock tensile tester, which belongs to the technical field of measurement and testing of solid materials. Background technique [0002] The maximum tensile stress that a rock mass can withstand when stretched in one direction is called uniaxial tensile strength, or tensile strength for short. Although in engineering practice, tensile stress seldom occurs, the damage caused by tensile stress is still one of the main failure forms in the field of engineering materials and natural rock mass, and the tensile strength of rock is relatively low, and the compressive strength is about 10 ~30 times the tensile strength. Therefore, tensile strength is an important index in rock mechanics. Tensile strength is one of the very important parameters in the establishment of rock mass strength criteria, the determination of strength envelopes and the selection of building stones. It is of great significance to carry out the research on the t...

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Problems solved by technology

Among them, indirect measurement methods include splitting method, point load method, etc. These methods mainly use the compressive strength of the rock to indirectly reflect its tensile strength, but the factors that play a decisive role in the tensile strength of the rock are the factors of the nature of the rock itself. , such as mineral composition, intergranular connection, pores and cracks, etc., and the way of compressive load and tensile load is essentially different, so there are many disadvantages in the indirect measurement method, which will cause large errors

[0004] The cap-type device with a spherical seat first used by the Yangtze River Research Institute in China has always been recommended in the relevant test specifications as a direct rock tension device. However, it is not difficult to find in the test that the rotation flexibility of the device is not enough, and it is difficult to avoid Eccentric tension

The invention patent "A system and method for direct tensile strength and deformation measurement of rock" (patent number: Zl201310697933.6) discloses a method for direct tensile strength and deformation measurement of rock. The rock sample is a hard and brittle material, and it is difficult to precisely process it

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