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Study on fissure evolution of overlying rock in lower protective mining
1Department of Resources and Mechanical Engineering, Lyuliang University, No. 1, Xueyuan Road, Lishi District, Luliang City, 033000, Shanxi Province, China. wangxiaolei@llu.edu.cn.
Scientific Reports
|August 19, 2024
Summary
Protective layer mining significantly enhances fissure development, increasing crack width and quantity. This method effectively reduces the stress in coal seams, preventing dangerous coal and gas outbursts.
Area of Science:
- Mining Engineering
- Geotechnical Engineering
- Rock Mechanics
Background:
- Protective layer mining is crucial for preventing coal and gas outbursts.
- Current research lacks detailed analysis of protective layer effectiveness and suffers from experimental errors due to limited measurement points.
Purpose of the Study:
- To investigate the protective effect of protective layer mining on stress, plastic damage, and pressure relief.
- To analyze crack evolution and expansion characteristics during protective layer mining.
Main Methods:
- Utilized deep base point technology to detect crack evolution in downhole drilling.
- Conducted field tests on the 2305 working face in a Shanxi mine.
Main Results:
- Protective layer mining significantly increased crack width and quantity, improving fissure development.
- Rock layer settlement exhibited periodic, nonlinear changes across three deformation stages.
- Plastic damage, pressure relief, and expansion curves showed a 'saddle type' pattern, reducing the overall pressure discharge rate by 60%.
Conclusions:
- Protective layer mining technology effectively improves fissure development and reduces stress.
- The technology meets critical expansion rate requirements for preventing coal and gas outbursts.
- This method is applicable to other working faces within the coal mine.
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