油砂的蠕变特性与本构模型研究  

Creep behavior of oil sand and its constitutive model

作　　者：王者超[1,2] Ron Wong 乔丽苹[3] 

机构地区：[1]山东大学岩土与结构工程中心,山东济南250061 [2]卡尔加里大学土木工程系 [3]山东大学工程力学系,山东济南250061

出　　处：《岩土工程学报》2012年第8期1412-1424,共13页Chinese Journal of Geotechnical Engineering

基　　金：中国博士后科学基金项目(20110491597);山东省优秀中青年科学家科研奖励基金项目(BS2011HZ008);教育部高等学校博士学科点专项科研基金项目(20110131120075)

摘　　要：油砂是一种富含天然沥青的沉积砂。作为一种软化材料,油砂的蠕变性质较松砂和正常固结黏土等硬化材料更为复杂。通过开展油砂三轴蠕变试验,获得了不同应力和应变状态下油砂的蠕变特性;讨论了蠕变势与塑性势之间的关系,提出了等效变形过程的概念,分析等效变形过程的微观机制;讨论了蠕变速率与时间和不可恢复应变之间的关系,提出采用不可恢复应变作为内变量可以描述复杂条件下油砂的蠕变性质,并据此提出了油砂的内变量蠕变模型;应用临界状态理论,分析了硬化型和软化型土的蠕变性质;讨论了剪切带对密砂蠕变性质的影响。Oil sand is a kind of sedimentary sands, whose pores are mostly filled with natural bitumen. As a strain softening material, the oil sand exhibits more complex creep behavior than the strain hardening materials, such as loose sand and normal consolidated clay. A series of triaxial creep tests are performed on the oil sand to obtain its creep behavior under different stress and strain states. The potential for creep is compared to that for plastic deformation. The concept of equivalent deformation processes is proposed and its microscopic mechanics is presented. The relation between creep rate and time, and that between creep rate and irreversible strain are discussed. An internal-variable creep model for the oil sand is proposed. In the model, the irreversible strain is considered as the internal variable for the description of oil sand creep. The creep behavior of both strain hardening and softening soils is postulated according to the critical state theory. The influence of shear band on the creep behavior of the oil sand is also investigated.

关 键 词：油砂 三轴蠕变性质 蠕变模型 内变量 蠕变势 应变路径 临界状态 剪切带 

分 类 号：TU431[建筑科学—岩土工程]