赤泥基粉砂土击实水敏性试验研究

Experimental study on compacted water sensitivity of red mud-based silty sand soil

为研究不同改良材料下赤泥基粉砂土的击实水敏特征,开展了不同水泥、石灰和粉煤灰掺量下的赤泥基粉砂土击实试验研究。结果表明:随赤泥掺量的增大,粉砂土的最优含水率随之增大,最大干密度先增大后减小,赤泥掺量为8%时最大干密度达到峰值;赤泥基粉砂土整体水敏性较强。掺入水泥和二灰(石灰、粉煤灰)可对赤泥基粉砂土形成物理和化学改良作用,改善其击实水敏性。随水泥与二灰掺量的增加,赤泥基粉砂土最优含水率逐渐增大,最大干密度逐渐减小;同等赤泥掺量下,二灰改性赤泥基粉砂土的最大干密度均小于水泥改性赤泥基粉砂土。水泥与二灰对赤泥基粉砂土的水敏性均有改善作用,但当其掺入量过大时,土的水敏性增强。二灰对于赤泥基粉砂土的水敏性改善效果优于水泥,采用二灰改性赤泥基粉砂土更利于该类材料的施工含水率控制,减少施工能耗。

In order to study the compacted water sensitive characteristics of red mud-based silty sand soil with different improved materials, the compaction tests of red mud-based silty sand soil with different cement, lime and fly ash contents were carried out. The results show that with the increase of red mud content, the optimal water content of silty sand soil increases, and the maximum dry density increases first and then decreases. When the red mud content is 8%, the maximum dry density reaches the peak. Red mud-based silty sand soil has overall strong water sensitivity. Adding cement and lime-ash(lime, fly ash) can improve the physical and chemical properties of red mud-based silty sand soil and improve its compacted water sensitivity. With the increase of cement and lime-ash content, the optimal water content of red mud-based silty sand soil increases gradually, while the maximum dry density decreases gradually. With the same red mud content, the maximum dry density of red mud-based silty sand soil modified by lime-ash is less than that of red mud-based silty sand soil modified by cement. Both cement and lime-ash can improve the water sensitivity of red mud-based silty sand soil, but when the amount of cement and lime-ash is too large, the water sensitivity of soil is enhanced. The improvement effect of lime-ash on water sensitivity of red mud-based silty sand soil is better than that of cement, and the modification of lime-ash on red mud-based silty sand soil is more conducive to the control of water content and the reduction of construction energy consumption.