不同混合度土石混合体振动压实能量耗散机制研究

Study on the energy dissipation mechanism of vibrating compaction behavior of soil-rock-mixture with different mixing degree

为了研究土石混合体混合度是否影响其作为填料的振动压实效果,采用离散元法对不同混合度土石混合体开展了数值模拟。研究结果表明:相同振动荷载周期时,土石混合体的压实效果随混合度增加而变好,且增加效果对高含石量土石混合体更显著,建议采用含石量体积分数为70%左右混合均匀的土石混合体为填筑料。另外,从能量耗散角度对振动压实过程中的压实机制进行分析,发现加载过程中阻尼耗能、滑动耗能和滚动耗能是促进土石混合体孔隙比减小的主要因素,其他耗能形式对孔隙比的影响较小;阻尼耗能、滑动耗能和滚动耗能随荷载周期的变化趋势相似,即加载初始耗能快速增加,耗能增速随荷载周期逐渐变缓,直至加载后期趋于稳定,该演变趋势与振动压实过程中土石混合体内部结构变化密切相关。

In order to study whether the mixing degree will influence the vibrating compaction behavior of soil-rock-mixtures(SRMs),the discrete element method(DEM)simulations of SRMs with different mixing degree were conducted.The research results show that the compaction effectiveness of SRM increases as the mixing degree increases at the same loading cycle.Furthermore,this increase effect is more significantly for SRM with high rock contents.Our simulations suggest that the uniform SRM with nearly 70%rock contents is a recommended filling.Additionally,the compaction characteristics of SRMs under vibration effect are explained from the perspective of energy dissipation.It is found that the damping energy dissipation,friction energy dissipation and rolling energy dissipation are the main energy items to result in the decreasing the void ratio of SRMs,and effects of others energy items can be ignored.Furthermore,the evolutions of damping energy dissipation,friction energy dissipation and rolling energy dissipation with loading cycle are similar.Specifically,at the initial loading cycle,these energy items rapidly increase,then the growth slow down and become stable at the end of loading cycle.This evolution trend is closely related to the variation of internal structure of SRMs during the vibrating compaction process.