Abstract: Elastic coefficient (k) of cemented filling materials and roof-untouched filling height (h) are key impact factors on the roof stability in cemented filling mining. Based on the principle of flexible supporting, roof deformation was divided into two stages, i.e., under the gravity stress of overburden rock and the roof presented flexural deflection. Both roof and cemented filling materials under the gravity stress of overburden rock were contacted with each other. Accordingly, mechanical models were established for each stage. Panlong Lead-Zinc deposit in Guangxi was selected as the case study to investigate the characteristics of roof deflection with different roof-untouched filling heights and elastic coefficients. The results show that roof-untouched filling height is the dominant factor which affects the deflection of the roof when k≥0.1 GN/m3, and the elastic coefficient would play the key role when k≤ 0.1 GN/m3. Cemented filling materials can effectively control the movement of roof strata and reduce the strain energy stored in roof strata when k≥0.1 GN/m3 and h≤300 mm. The theoretical analysis results are consistent with the in-situ drilling, indicating the feasibility of this study.

Key words: flexible supporting, elastic coefficient, roof-untouched filling height, roof deflection, strain energy