Experimental study on improving the performance of fluid solidified soil based on optimization of solidifying agent...

Fluid solidified soil using Portland cement solidifying agent is a widely used material in backfill engineering, but the performances of solidified soil using one component cement solidifying agent is related to the proportion of solidifying agent, and its economy and environmental friendliness are poor. To improve the performances of fluid solidified soil, fly ash and mineral powder were used to instead of some of cement content to prepare a three-component solidifying agent (cement, fly ash and mineral powder) and vibration mixing was used. The influence of multi-component solidifying agents on the performances of fluid solidified soil was explored. The experimental results showed that using fly ash content of 10%, 20%, and 30% as substitutes for the equal cement content, the 28d compressive strength of fluid solidified soil decreased by 6.9%, 13.4% and 22.8%, respectively. With the replacement of mineral powder content of 10%, 20% and 30%, the 28d compressive strength of fluid solidified soil increased by 8.4%, 17.3% and 28.2%, respectively. With the replacement of mineral powder and fly ash content 30% (cement of 70%, mineral powder of 15% and fly ash of 15%), the 28d strength of solidified soil three-component solidifying agent increased by 33.2%. Under the same solidifying agent ratio, compared with ordinary mixing, the 28d strength of solidified soil using vibration mixing increased by 7.7%. Compared with solidified soil using cement solidifying agent, the water stability of that replaced by three-component solidifying agent increased from 0.84 to 0.92, and the compressive strength loss under wet dry cycles was also smaller. On this basis, by using vibration mixing, the water stability of the solidified soil was improved by 5.6% under the same mix ratio. The study on the addition of multi-component solidifying agents containing fly ash and mineral powder and vibration mixing has improved the strength and workability of solidification, as well as the utilization rate of industrial mineral powder, providing reference for the application of solidified soil engineering.