Pressure head device for loading normal triaxial rheology and testing acoustic emission under high confining pressure

Abstract

The invention discloses a pressure head device for loading normal triaxial rheology and testing acoustic emission under high confining pressure. Vaseline is applied on a piezoelectric ceramic surface of a sensor, the sensor is placed into a sensor room and fixed at the bottom, a flexible spacer is placed between the sensor and a fastening bolt, the fastening bolt, a side seal ring and a side sealcover are installed in a side seal chamber through a slot of the fastening bolt, a sticky steel type structural adhesive is poured into a recess part and an outlet hole of the side seal cover, a mainseal ring is arranged into a seal groove, a main seal cover and a pressure head seat body are sealed through the bolt of the main seal cover, a storehouse seal ring and a storehouse seal cover are installed in a storehouse seal chamber, a lower pressure head centering guide slot centers the center of a testing system pressure axis, an upper pressure head is arranged on a rock sample, and coaxial cables of the upper pressure head and the lower pressure head are linked through convex-concave joints of coaxial cable yarns. The invention is widely used for indoor emission tests of failure mechanisms, failure modes and damage evolution rules of soft and hard rocks in the rheology process.

Description

technical field [0001] The invention belongs to the technical field of rock mechanics test and acoustic emission monitoring, and more specifically relates to an indenter device capable of performing conventional triaxial rheological tests under confining pressure and monitoring acoustic emission characteristics of rock fracture during the rheological test process. The device can be widely used in routine triaxial rheological tests of rocks in mining engineering, water conservancy and hydropower engineering, petroleum engineering, geotechnical engineering and underground engineering. Background technique [0002] Under the action of external force, when new cracks are generated inside the rock material and the old cracks expand, the strain energy is transiently released to generate elastic waves, that is, acoustic emission information is emitted. Microcracks of different sizes and forms are released by the rock mass. The strength and characteristics of the acoustic emission s...

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Problems solved by technology

[0004] Conventional triaxial and true triaxial indoor rock acoustic emission mechanical tests, due to the existence of oil pressure in the pressure chamber, the sensor protection is difficult, therefore, most of the research results are the results under low confining pressure, and some of the research results under high confining pressure The results are mainly measured by arranging the sensors on the upper and lower bases of the test system. Due to the long distance between the sensors and the rock samples, coupled with the attenuation between the media, the acoustic emission signals are not ideal, and the test results are also greatly reduced.

[0005] The conventional triaxial rheological acoustic emission rock mechanics test under high confining pressure is of great significance to the analysis and research of the long-term stability of deep-buried rock engineering, but the research on the conventional triaxial rheological acoustic emission rock mechanics test under high confining pressure has not been seen in Relevant literature reports that the main reason is that the rheological test is a long-term mechanical test. Under long-term high confining pressure, 1) the sensor is difficult to protect, and the piezoelectric ceramics of the sensor are easily damaged by oil pressure; 2) when the coaxial cable of the sensor is drawn out, Oil leakage is prone to occur, resulting in the failure of the triaxial rheological acoustic emission test; 3) Due to the stress concentration between the embedded indenter of the sensor and the rock sample, the end effect is very obvious, and the test results are not ideal

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