Abstract: The cut-and-fill mining method requires the material used for backfilling owning a certain strength to ensure safety recovery.Traditionally，filling designs are determined by laboratory experiments of mixture ratio，but the filling body is non-uniform due to the segregation of the filling slurry in layers.The difference of design strength of fill body differs greatly from that measured on site，resulting in the safety problems in production.This paper describes a simple，reliable method to measure the cement content in fill body and to systematically study the inhomogeneous property through simulation experiment of water tank.The results show that the strength of the fill body with sand-cement ratio of 4 has an S-type distribution，while that with sand-cement ratio of 10 shows a linear decrease of strength with body length.The low sand-cement ratio fill object shows a characteristic of locally uniform and layered structure which results in the following conclusions: the strength of fill body is not directly proportional to cement content and a high content of cement does not necessarily imply a high strength since the aggregation of cement particles in large amounts adversely affects the strength of fill body.

Key words: Fill-body, Cement content, Intensity distribution, Inhomogeneous