Abstract: In order to research ground surface deformation law of extra-thick coal mining under the condition of massive conglomerate stratum, according to probability integral model, 3D distributed mathematical functions to determine optimum parameters have been made based on superposition principle. In response to ground surface movement surveying datum of 2113 panel of Changcun colliery, surface deformation prediction parameters have been obtained by using subsidence and horizontal movement functions. Associated with engineering geological data, parameters distribution law has been analyzed from overburden terrane movement mechanism. The results show that first weighing interval of thick conglomerate is 367 m, while period weighing interval of cantilever is 179 m. Ground surface discrete deformation present intensively after key-strata collapses. And the cantilever bear action of massive conglomerate stratum mainly causes dissymmetry subsidence basin. The results are in accordance with field surveying datum.

Key words: massive conglomerate, mining subsidence, optimum obtaining parameter, movement mechanism, key stratum