Yuan Kekuo, Lu Yating, Li Wanlu, Yu Hongdan, Gao Shan
College of Civil Engineering, Xijing University, Xi'an 710123, China.
Shanxi Key Laboratory of Safety and Durability of Concrete Structures, Xi'an 710123, China.
Materials (Basel). 2022 Oct 4;15(19):6891. doi: 10.3390/ma15196891.
Underground void subsidence hazards, especially mine goaf, have now become one of the major social problems affecting the well-being of civilians and development in China. The objective of this study was to propose a kind of strong thixotropic engineering slurry and filling treatment for use in underground void subsidence hazards. The optimal agent ratio for thixotropic cement slurry/mortar was obtained by indoor tests, where the rheological agent is 7.5% compared to the weight of cement, the water-solid ratio is in the range of 0.70.8, and the aeolian sand ratio can be 01.5 times that of cement. The rheological properties of slurry and mortar were tested using a Brookfield RST-SST rheometer. The results show that aeolian sand can be used as thixotropic cement mortar for a backfilling treatment for underground voids (mine goaf). The static yield stress increases non-linearly compared to existing thixotropic models. The stress decays sharply with shearing (the shear rate is more or less 10 s) and then the stress increases with the increase in shear rate (the shear rate is more than 10 s). The increase in the stress of the slurry is greater than in the mortar. A natural logarithmic function between yield stress and rest time (only 1 parameter), an exponential function with two parts for stress-shear rate (a rheology model, with only 3 parameters), and an exponential function for the accumulation law (only 2 parameters) were proposed in turn.
