Study on Occurrence Mechanism of Coal Pillar in L-Shaped Zone during Fully Mechanized Mining Period and Prevention Technology

Table 3

Critical index values of burst potentiality about roof and floor.

Burst potentiality testing indexes, UWQ (kJ)	Burst potentiality degree	Classification
UWQ < 10	No	I
10 < UWQ ≤ 100	Weak	II
UWQ > 100	Strong	III