Mechanical Analysis of Roof Subsidence Based on Rheological Properties of Solid Backfill Materials

Abstract

To study the influence of the rheological properties of backfill materials on strata movement during solid backfill mining, Poyting-Thomson model was selected as the rheological model for the backfill materials based on their experimentally derived rheological properties. By regarding the roof as a thin elastic plate, a rheological mechanical model of the roof when using solid backfill mining, was established. According to the elastic-viscoelastic correspondence principle, the deflection of the roof at different times was obtained by use of the energy method. By taking the 7203W backfill mining panel of a coalmine in Zhaizhen town as an example, the subsidence of the roof over time was calculated. Results showed that the maximum subsidence was 205 mm, which was close to that measured in situ. Meanwhile, the observation of boreholes drilled into the roof evinced its integrity. Therefore, these results can provide a theoretical basis for predicting strata movement and surface subsidence during solid backfill mining.

Keywords

• backfill materials
• rheological properties
• roof subsidence
• solid backfill mining