【摘要】 通过分析非饱和黄土动残余应变的物理过程与力学机制,研究影响动残余应变的关键参量;结合室内动(静)三轴试验数据,提出应用关键影响参量求算该动残余应变的分布拆解方法。结果表明,非饱和黄土动残余应变实质上是土体广义固相介质响应外部动荷载作用的再固结过程,其关键影响参量可归纳为土体广义固相介质的强度、体积特征和外部动荷载特征。强度特征对应土体抵御外部荷载的能力,可用室内土工测试获取的黏聚力与内摩擦角宏观表征;体积特征反映土体潜在的再固结性态,可用表征土体欠压密程度的孔隙比描述。基于非饱和土三相概念的分布拆解方法,其求算过程具备较为明确的物理含义,对建立合理、实用的非饱和黄土动(静)塑性形变本构关系具有理论意义。更多还原

【Abstract】 By analyzing the physical process and mechanism of the dynamic residual strain of unsaturated loess,critical influence parameters are investigated.By contrast with laboratory data of unsaturated loess specimens under dynamic/static triaxial tests,consequently,a magnitude estimation method with two individual formulas is proposed for the dynamic residual strain of nature loess.The analysis results show that the dynamic residual strain of unsaturated loess could be described as a consolidation response of generalized solid-phase-media of loess mass under external dynamic loads.Meanwhile,critical parameters influencing the dynamic residual strain of unsaturated loess include two aspects,which are the strength and volume characteristics of the generalized solid-phase-media and the external dynamic loads features,respectively.For above-mentioned critical characteristics,the strength could be figured by cohesion and internal friction angle,both expediently obtained through laboratory geotechnical tests,while the volume could be described by void ratio,which reflects the under-compacted status of loess mass.Generally,the former shows the endurance capacity of loess to resist external dynamic loads and the latter describes the settlement capacity of loess under an external dynamic load.In the analysis of magnitude estimation method for dynamic residual strain of unsaturated loess proposed here,the results of physical mechanism and critical influence parameters are considered comprehensively.It will be helpful,therefore,to establish a reasonable and practical constitutive model for plastic deformation of unsaturated loess under dynamic/static loading.更多还原