基于UDEC的不同预裂参数下顶板垮落规律研究OA

In order to solve the problems of excessive initial collapse step distance and rock pressure manifestation along the goaf in the fully-mechanized mining face of extra thick coal seams,numerical simulation methods were used to analyze the influence of different cutting depths and angles on the collapse law of the roof,with a focus on exploring the collapse status of the top coal roof during the ini-tial mining period.The results show that cutting the roof can significantly improve the collapse of roof,and cutting depths of 10 and 15 meters have a significant effect on reducing residual coal,relieving roof pressure,and reducing stress concentration in the roadway.The cutting depth has a significant impact on the peak stress and stress concentration factor:when there is no cutting depth,the peak stress reaches 6.88 MPa,and when the cutting depth is 5 m,the peak stress decreases by 26.88％.When the cutting depth is 10 m and 15 m,the peak stress decreases by 56.25％and 40.15％,respectively.In addition,when the top cutting depth is 10 or 15 meters,the stress distribution of the coal pillar does not change much and is more conducive to the stability of the surrounding rock.However,during the process of clearing collapsed coal,attention should be paid to the changes in the support of the deep rock mass of the roof.The research results can provide reference for optimizing the top cutting depth parameters.