In order to explore transfer bearing mechanism of thick composite roof in gob-side entry retaining

combining with characteristics that the composite roof is soft and proteiform and which leads to roof caving in gob-side backfill zone and roof cutting inside entry

systematic stiffness equation of roof

wall and floor is acquired through establishing mechanical model of supporting system beside entry

absorbing deformation characteristics are finally expounded. Roadway-side support system consists of direct roof

wall and direct floor

which bears the roof pressure integrally. The systematic stiffness is increasing with the rising of the stiffness of roof and floor; the rising effect is apparent when the original stiffness is low

in particular. The thick composite roof has a good performance on absorbing deformation

which is beneficial to relieving the pressure of roadway-side wall. For enhancing systematic stiffness of god-side support and strengthening transfer bearing ability of thick composite roof

the integral reinforcing technology is put forward. The research results have been applied to the condition of 10 meters composite roof successfully.