Rock tensile strength measuring device and measuring method

Abstract

The invention discloses a rock tensile strength measuring device and a measuring method. The device comprises a lower seat, an upper seat, a lower pressure-resistant block, an upper pressure-resistantblock, a force application mechanism and a displacement sensor; the force application mechanism comprises a cylinder sleeve and a piston rod, the cylinder sleeve is arranged in the lower pressure-resistant block, a high-pressure cavity is formed between the bottom of the cylinder sleeve and the lower pressure-resistant block, and the top end of the piston rod extends out of the cylinder sleeve tomake contact with the upper pressure-resistant block; one side of the upper seat is connected with the upper pressing block, and a tensioning reset mechanism is arranged between the lower seat and the upper seat and / or between the lower pressure-resistant block and the upper pressure-resistant block. The lower seat is connected with the lower pressure resistant block through a high-pressure connector, an output port of the high-pressure connector is communicated with the high-pressure cavity; fluid is input from the high-pressure connector to drive the piston rod to move so as to realize external expansion of the lower pressure-resistant block and the upper pressure-resistant block, so that a rock sample to be tested is subjected to tension damage. The rock sample to be tested cracks fromthe separation part of the upper pressure-resistant block and the lower pressure-resistant block, and the cracking position of the test is controllable, so that the repeatability of the test is ensured.

Description

technical field [0001] The invention belongs to the technical field of indoor testing of rock mechanical properties, in particular to a measuring device and a measuring method for rock tensile strength. Background technique [0002] The tensile strength of rock is an important mechanical property of rock, and it is also an important parameter in the stability analysis of rock structure. The tensile strength of rock is much smaller than its compressive strength. When the tensile stress on the rock is higher than the tensile strength of the rock, the rock will undergo tensile failure. Therefore, it is of great significance to accurately obtain the tensile strength of the rock for the study of rock failure. [0003] At present, the methods for measuring the tensile strength of rocks include direct tension method, split method and point load method. However, these testing methods have some shortcomings: [0004] (1) A more accurate tensile strength value can be obtained by usi...

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Problems solved by technology

[0004] (1) A more accurate tensile strength value can be obtained by using the direct tension method, but it is difficult to prepare the specimen by this method, the test technology is complicated, and the position of the tensile failure section of the specimen is difficult to control, and it is easy to connect the specimen to the fixture Broken, affecting the test accuracy;

[0005] (2) When the tensile strength value of the rock is measured by the splitting method, the compressive stress area near the contact position between the end of the sample and the loading block is unavoidable, resulting in the measured tensile strength value being too large;

[0006] (3) When the tensile strength value of the rock is measured by the point load test, the test results are highly discrete. In order to ensure the test accuracy, the test generally stipulates that each group of tests must reach a certain number, usually more than 15 test pieces, and then take Average, time consuming

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