An improved Bingham fractional creep damage model of filling body containing water

Filling mining technology is an important representative technology to realize green and low-carbon mining. The filling body has distinct rheological characteristics under the long-term action of formation loads and groundwater seepage. In order to study the creep characteristics of filling body under different moisture contents and reveal its aging-mechanical properties, an improved Bingham fractional creep model was established to describe the whole process of creep based on the traditional Bingham model. Based on the experimental data of gangue cemented backfill under different moisture content, the parameters of creep model are obtained by using user-defined function fitting and least square method. The results show that the improved Bingham fractional creep model can well describe the whole creep process of filling body under different moisture contents. Compared with the traditional Bingham model, the fitting degree is higher, which solves the problem that the Bingham model cannot describe the nonlinear creep stage. Model parameter α and ξ increase with the increase of axial stress and moisture content. Under the same moisture content, η gradually increases with the increase of axial stress. This work has a certain reference significance for studying the mechanical properties and creep constitutive model of filling body containing water.