Analysis of fault separation generation and its increasing effect on mining zone

When fault exists in overburden strata,the earth-surface subsidence laws would be greatly different from the laws without faults. To study the effect of fault on mining zone transferring,the principle of spatial conservation and nu- merical simulation were utilized to find that there is fault separation space and the earth-surface subsidence zone would be greater based on theoretical derivation. The results showed that the increased subsidence zone is mainly from the fault separation space and the space below key-strata is from broken rocks being compressed again,while the space a- bove key strata was mainly from the decrease of bed-separation. At the same time,the influence factors of fault separa- tion are mining length,bedrock height,protecting coal pillar width,mining height and fault dip. Also,the occurrence of fault separation is decided by the relationship between fault dip and main influence angle. The research result is of sig- nificance for studying the earth-surface subsidence laws when there are faults in overburden rock and improving the precision of subsidence prediction.