考虑残余含气量的非饱和土的水力耦合本构模型  

Hydro-mechanical coupling constitutive model of unsaturated soils considering effect of air entrapment

作　　者：马田田[1] 韦昌富[1] 陈盼[1] 李文涛[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071

出　　处：《岩土力学》2014年第12期3415-3420,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.11072255);广西自然科学基金(No.2011 GXNSFE018004)

摘　　要：大量的非饱和土干湿循环试验表明,当土体处于吸湿过程直至吸力降低为0 k Pa时,土体并不能达到完全饱和状态,还存在一定的残余气体。在高饱和度时,由于残余气体以封闭气泡的形式分布在土体中,土体呈现较大的压缩性,使其与饱和土的性质不同。在这种状态下,现有的非饱和土本构模型预测到的土饱和度为100%,与试验结果存在一定的偏差。为了使本构模型在高饱和度状态时具有较高的精度,对非饱和土的毛细滞回和塑性变形耦合本构模型进行了修正,使其能够考虑残余含气量的影响。通过预测与实测结果比较,证明了新模型能够有效地模拟残余含气量对非饱和土力学特性的影响。Sufficient experimental evidence shows that a soil cannot reach the fully saturated condition during wetting process, even the matric suction decreases to 0 kPa, and small amount of air is trapped in the pores, rendering the soil to be more compressible than expected in the early beginning of compression process. At this state, the behavior of the soil is different from that of its saturated counterpart. On the other hand, existing coupling constitutive models of unsaturated soils would predict that the soil becomes fully saturated, which is inconsistent with experimental results. Considering the air entrapment effect, a constitutive model with coupling capillary hysteresis and plastic deformation is modified. Comparison of the simulated results and experimental data illustrates that the new model can effectively address the effect of air entrapment on the behavior of unsaturated soils.

关 键 词：非饱和土 残余气体 耦合本构模型 毛细滞回 

分 类 号：TU431[建筑科学—岩土工程]