Abstract: Based on the instability characteristic of a sedimentary bauxite goaf mine， which showing a shear failure along weak structural planes， a catastrophic sliding model of a pillar-roof supporting system was established by using the energy dissipation theory and the catastrophe theory. The instability mechanism related to the weakness structural plane was studied， and the influence of various internal control factors on the stability of the goaf was analyzed. The results indicate that the sudden sliding instability of the goaf is caused by the combined action of the internal and external control factors of the supporting system. When the external control factors are fixed， the sensitivity of each internal control factor can be listed from large to small as: goaf span b， pillar width a， thickness of weak zone B， structural weakness plane angle θ， pillar yield zone width c. The sensitivity of the thickness B of the weak zone and the inclination angle θ of the weak structural plane are just slightly smaller than that of the goaf span and the pillar width， which means that the influence of the weak structural plane should be paid more attention in actual projects. The reliability of the calculation results was verified in the Chenguang bauxite project. The research results can provide basis for stope parameter design of such mines.

Key words: pillar-roof supporting system, sliding instability, structural surface, bauxite, catastrophe theory