Deviatoric stress evolution laws and control of surrounding rock at gob-side entry retaining in deep backfilling mining

In order to solve the surrounding rock control problems of gob-side entry retaining in deep backfill mining, taking the No. 1126 haulage roadway in Xingdong coal mine as an example,the Strain Softening model was adopted to simulate the deviatoric stress and plastic zone evolution laws of the surrounding rock at the gob-side entry retaining during the whole process of advancing with the working face. The results show that ① the more obvious influence zone of the advanced mining about is 32 m on the roof,but about 16 m on floor and two ribs. The more obvious influence range of the lag mining about is 32 m on the roof,but about 24 m on floor. ② The monitoring sections are monitored from the beginning to the end of working face mining during the whole process of advancing with the working face. It is concluded that the evolutional sequence of deviatoric stress distribution form is thin elliptical shape,approximate circle shape,small semicircle arch,large semicircle arch,and fantail arch. The peak value zone of deviatoric stress is trans- ferred from the roof-to-floor to the corner of roof and floor in solid coal side and the solid coal side. Meanwhile,the or- der of plastic zone evolution state of the surrounding rock of the gob-side entry retaining as follow:Approximate elliptical shape,approximate circle shape,hemisphere shape,the plastic zone of the surrounding rock is asymmetric distribu- tion. ③ Based on the asymmetric distribution characteristics of deviatoric stress and plastic zone in gob-side entry re- taining with deep backfilling mining,the asymmetric control technology of surrounding rock in areas was proposed and applied in the field test. The surrounding rock deformation of gob-side entry was effectively controlled.