Research on the Constitutive Model of Steel Slag-Mineral Powder Modified Loess-Red Bedded Mudstone

Aiming at the geological characteristics of loess overlying red-bedded mudstone in the Gansu area, two kinds of industrial solid wastes, namely steel slag and mineral powder are adopted to carry out the research on the mechanical properties and the constitutive model of the modified loess-red bedded mudstone mixed fill by compacting and triaxial CU test. The results show that: (1) The maximum dry density of the mixed fill is the largest when the mass ratio of loess: red mudstone is 1:3. (2) The shear strength of steel slag is maximum when the mass dosing of steel slag is 7.5%. The larger the mass dosing of mineral powder is, the larger the shear strength is. (3) It is verified that the strain hardening process of soil samples before and after steel slag improvement could be accurately fitted by the Duncan-Zhang model. (4) For the problem that the hyperbolic model promoted by Shen Zhujiang can not fit the strain hardening well, this paper proposes to use the staged fitting method with positive and negative solutions, and it is verified that this method can accurately fit the strain hardening process of the mineral powder amended soil.