Comprehensive Analysis of Stability of Coal Seam Composite Roof Based on Analytic Hierarchy Process

Table 6

Rock layer strength contribution rate .

Strata location (number of strata)	Two layers	Three layers	Four layers and above
First layer	0.6667	0.5396	0.4673
Second layer	0.3333	0.2969	0.2772
Third layer	–	0.1634	0.1601
Fourth layer and above	–	–	0.0954