Coal-rock hydraulic fracturing testing method under true triaxial state

Abstract

The invention discloses a coal-rock hydraulic fracturing testing method under a true triaxial state. The coal-rock hydraulic fracturing testing method under the true triaxial state comprises the following steps: 1) preparing a test piece; 2) installing the test piece; 3) pre-loading; 4) loading; 5) hydraulically fracturing; 6) unloading; 7) storing all data recorded by a data collection system, taking out the test piece and observing the shape of the test piece. According to the coal-rock hydraulic fracturing testing method, the real work condition can be more really simulated, and a theoretical basis is provided for solving on-site problems.

Description

technical field [0001] The invention relates to a coal rock hydraulic fracturing test method in a true triaxial state. Background technique [0002] Coal and gas outburst is an extremely complex dynamic phenomenon that occurs underground in coal mines. It can eject a large amount of coal and gas from the coal body to the mining space in a very short period of time, which seriously threatens the safety and security of coal mines in my country. Miners' lives are safe. Therefore, it is very important to strengthen the research on the mechanism of coal and gas outburst. Studies have shown that coal and gas outburst is the process of shear failure of coal body under the cyclical action of internal and external stress, that is, the internal and external stress induced by changes in the ground stress field, coal rock structure, and gas state and flow due to mining activities. Under the action of external forces, when the coal body is partially fractured and damaged to form an outb...

AI Technical Summary

Problems solved by technology

Deep high temperature and a series of problems caused by it have become a difficult problem in deep mining. At present, the research on the influence of temperature in deep mining is still in the initial and qualitative stage. The main problems are as follows: the real stress environment is not considered; In the constitutive equation of the rock rheological model established under the coupling of temperature and pressure, the consideration of temperature as a linear factor needs to be proved and improved when the temperature field distribution and temperature change have not been specifically clarified; The influence of temperature on transformation lacks quantitative analysis, and no specific parameter equation with general significance has been formed. There is no clear mathematical formula to express the range, degree of influence and mechanism of temperature in brittle-ductile transformation; The calculation of rock mass damage under TM coupling and the relationship between the two types of damage still need further research and proof; for the coupling between temperature-pressure-water-time and the influence form and depth of temperature under the influence of several factors In-depth research is still needed; the study of temperature should focus on the process of dynamic changes, and conduct in-depth analysis from both micro and macro perspectives

Therefore, none of the above equipment can meet the experimental requirements for researching and solving the practical problems faced by coal mines at present and in the future

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