TITLE:
Comparative Analysis of the Distribution Characteristics of Floor Stress Field between Gob-Side Entry Retaining with Roof Cutting and Conventional Mining
AUTHORS:
Weifeng Xue, Chaoyang Liu, Chao Li, Yongguang Chen, Xiaoping Xi, Feng Wang
KEYWORDS:
Roof Cutting and Pressure Relief, Gob-Side Entry Retaining, Floor Stress Field, Stress Concentration
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.12,
December
7,
2022
ABSTRACT: All coal fields in North China are affected by floor confined water to
varying degrees, floor failure and water inrush risk have always been a major
problem to baffle coal mining activities. Roof cutting and pressure relief and
the lack of protective coal pillar can cause the change of floor stress field,
leading to the change of the floor failure depth, stress field of floor is the
key to determine the depth of floor failure. In order to deeply study the
distribution characteristics of floor stress field in gob-side entry retaining
mining with roof cutting, taking the 50107 and 50109 working faces of Dongdong
Coal Mine in Chenghe as the research objects, the numerical simulation software
is used to simulate the floor stress field distribution of gob-side entry
retaining mining with roof cutting and conventional mining. The distribution
characteristics of the floor stress field of the working face are compared and
analyzed under the three modes of conventional mining of reserved coal pillar,
the first mining face of gob-side entry retaining with roof cutting and
gob-side entry retaining with roof cutting. The results show that the peak
stress concentration in front of the working face all occurs at 10 m under the
three mining modes. The stress concentration area in front of conventional
working face of reserved coal pillar is mainly in the middle of the working
face. The stress concentration area in front of the first working face of
gob-side entry retaining with roof cutting
(50107) is located in the middle of the working face and the side of the
working face of the retaining roadway. The stress concentration area of the working face (50109) is mainly in the middle and the two ends of the
working face. The order of the peak value of the maximum concentrated stress in
front of the working face is conventional working face of reserved coal pillar
> the first working face of gob-side entry retaining with roof cutting
(50107) > working face of gob-side entry retaining with roof cutting
(50109). There is a stress reduction zone behind the working face, but there is
a stress concentration phenomenon extending to the outside of the roadway, and
the stress distribution is obviously different. Conventional working face of
reserved coal pillar and the first working face of gob-side retaining with roof
cutting (50107) show a double peak form of stress concentration on the outside
of the two ends of the roadway, and the peak value of the concentrated stress
at the rear of the working face is in the following order: On the side close to
the transportation roadway, conventional working face of reserved coal pillar =
the first working face of gob-side entry retaining with roof cutting (50107)
> working face of gob-side entry retaining with roof cutting (50109); on the
side close to the return airway, conventional working face of reserved coal
pillar > the first working face of gob-side entry retaining with roof
cutting (50107) > working face of gob-side entry retaining with roof cutting
(50109).