Abstract: Taking paste backfill working face 2351 for an example in Daizhuang coal mine, bearing characteristics of filling body and supporting intensity of working face during coal pillar mined with paste backfill have been studied. Based on the analysis of the motion characteristics of roof in coal pillar mined with paste backfill, the mechanical model of roof stability during coal pillar mined with paste backfill has been established, and the mechanics related formula of supporting intensity has also been concluded. Research has shown that: the strength of paste is high, elastic modulus and Poisson’s ratio are lower, the discreteness of mechanical properties is obvious, and that the paste has typical plasticity hardening features; The overlying strata of paste backfill working face has breaks, bed separation and bending zone rather than caving zone; The distribution of vertical stress above the filling body is not a horizontal line nor saddle-shaped as the strip coal pillar but presents wave distribution. The stress above the filling body is not mutational but tends to be increasing and stable at last. The hydraulic supports used in paste backfill face 2351 can control the roof subsidence effectively, but the efficiency of hydraulic supports is lower, which should be optimized properly.

Key words: strip coal pillar, paste backfill mining, bearing characteristics of filling body, supporting intensity of working face