Analysis on the strength increase law of filling material based on response surface method

In order to study the influence of cement content,fine gangue rate and water reducer content on filling mate- rial mechanical properties,some central composite design(CCD) experiments were performed to investigate the effect of the three factors on the compressive strength at different curing periods. Response surface regression models of the backfill strength of different ages were established by the software of Design-Export. The results show that the compres- sive strength of backfill is in proportion to cement content, water reducer content and inversely proportion to fine gangue rate in the overall curing period. The initial strength of backfill is not only largely influenced by cement con- tent,fine gangue rate and water reducer content,but also affected by the interacted affection of the three factors. The later strength of backfill is only largely influenced by single factor,the order of effective extent is cement content,water reducer content and fine gangue rate.