Abstract: In order to study on the mine strata pressure law under thick alluvium, taking the determination of high cutting fully mechanized coal mining face in the second panel of Tingnan Coal Mine as the engineering background, theoretical calculation and field measurement had been used. The results showed that the effects of thick alluvium were lagged: Because of tend to forming arch, the clay in thick alluvium had little influence on the roof strata control of mining face in a certain distance. With the mining face advancing, subsidence and fracture would occur in the key strata of C19 and the stability of the alluvium would be damaged, the alluvium load would transfer to working face through the rock stratum. When the mining face advanced to more than 198.5m, the work resistance of powered support and dynamic load factor had become higher, the pressurized distance had become shorter, and the pressure strength would increase periodically at this stage. Work resistance of powered support at the later stage was higher than the previous stage during the non pressured period. The work resistance at the middle part of the coal mining face was higher than at two ends, and the work resistance near talgate was higher than near the other gateroad.

Key words: thick alluvium, high cutting coal mining, mine strata pressure law, work resistance