摘要
针对西安地裂缝活动条件下黄土覆盖层裂缝的发展与形成,依据黄土的构度和应力比结构性参数变化规律,分析了黄土构度和抗拉强度之间的关系,建立了黄土结构性演变的数学模型,抗拉强度与抗剪强度随结构性参数变化强度准则,以及反映黄土结构性演变的Mohr-Coulomb屈服面弹塑性模型.通过本构模型嵌入FLAC3D软件,数值模拟西安地裂缝活动边界条件,以及结构性黄土地层结构,进行了黄土结构损伤变化和地层破裂带形成发展分析研究.表明地裂缝错动位移作用条件下,黄土地层塑形区域破裂带发展分为初始剪切破坏、初始拉伸破坏、剪切与拉伸破坏发展、破裂带贯通四个阶段;地层破裂带黄土的结构性损伤衰减变化突出,黄土应力比结构性参数等值线与地层塑性破裂带分布一致.揭示的黄土地层局部化破裂发展过程机制,对于认识地裂缝造成地面建筑物与地下工程灾害有重要的理论和实际意义.
Stuctural damage and fracture of loess strata is caused by the activity of ground fracture. First,bsaed on structural index and stress ratio structural parameter,we establish mathematical model reflecting the initial structure of loess and evolution under coupling of stress and moisture,and analyse variation of tensile strength and compression-shear strength of loess with structure. Second,we establish M-C structure constitutive model of hyper elasto-plasticity which reflects structure evolution of loess. Third,the constitutive model is compiled by Fish language to accomplish inserting FLAC3 D explicit finite-difference software. Finally,Stuctural damage and fracture of loess strata under acting ground fracture is very well simulated by the software,and we research on localized failure mechanism of ground fracture of loess strata. Research shows that the evolutionary process of ground fracture in loess zone divided into four stages： initial shear damage stage,initial tensile damage stage,tensile and shear failure development stage,failure surface through stage. Structural evolution of loess is very predominant in the process of progressive failure. The distribution of stress ratio structural parameter under acting ground fracture is consistent with the plastic zones. The results of the research have great significance both in theory sense and engineering practice to understanding the disasters of ground and underground buildings under acting ground fracture.
出处
《冰川冻土》
CSCD
北大核心
2016年第4期1150-1156,共7页
Journal of Glaciology and Geocryology
基金
陕西省科技厅基金项目(2014JQ5173)
陕西省教育厅基金项目(14JK1519)资助
关键词
黄土
结构损伤
结构性参数
地裂缝
破裂带
loess
structural damage
structural parameter
ground fracture
rupture zones
