风城油砂三轴力学特性及其本构模型研究  

Triaxial Mechanical Characteristics and Constitutive Model of Oil Sand in Fengcheng

作　　者：王俊[1,2] 谢凌志[2,3] 谢和平[1,2] 李存宝[1,2] 

机构地区：[1]四川大学建筑与环境学院,四川成都610065 [2]四川大学能源工程安全与灾害力学教育部重点试验室,四川成都610065 [3]四川大学新能源与低碳技术研究院,四川成都610065

出　　处：《四川大学学报（工程科学版）》2015年第5期1-9,共9页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家重点基础研究发展计划资助(2011CB201201);国际科技合作项目资助(2012DFA60760);四川省科技支撑计划资助(2012FZ0124)

摘　　要：油砂是一种具有自锁结构的致密沉积砂,其力学特性较疏松砂岩更为复杂。针对新疆克拉玛依风城油砂矿的储层岩芯,利用MTS 815试验系统开展室温三轴固结排水压缩试验,探讨了油砂在不同围压下的三轴力学特性。结果表明,典型的油砂应力–应变关系呈驼峰曲线,存在应变软化与剪胀现象;试验边界条件与围压对油砂力学特性具有重大影响,并决定了其破坏模式及峰后软化行为;油砂变形模量、泊松比在对数坐标下与围压存在线性关系,低围压时抗剪强度近似服从莫尔–库伦准则。借鉴南水非线性模型及成都科大模型,分别讨论了风城油砂的应力应变本构关系,在此基础上修正得到新的推广双曲线模型,指出修正的成都科大模型较南水模型能更好地描述油砂的应变软化特性,也能适当地考虑剪胀效应,以期为深入研究中国本土油砂的力学特性及石油工程应用提供指导。In oeder to study mechanical characteristics of the oil sand core of Fcngcheng oilfield in Xinjiang Karamay, a consolidated drained triaxial compression tests at room temperature were conducted on MTS 815, and the triaxial mechanics properties of oil sand un- der varying confining pressure were studied. Results indicated that the typical stress-strain curve of oil sand seems a hump curve, exhibi- ting strain-softening and shear dilatancy. Test boundary conditions and the confining pressure have significant influences on the mechan- ical properties of oil sand,which determine the failure modes and the post-peak softening behaviors. The deformation modulus and Pois- son ＇ s ratio of oil sand have linear relationship with confining pressure in logarithmic coordinates respectively, and the failure criterion of oil sand at low stresses can be explained approximately with the Mohr-Coulomb criterion. Based on two classical nonlinear constitutive models, by introducing new parameters, the stress-strain constitutive relationship of oil sand in Fengcheng was discussed,which demon- strated that the modified Chengdu Science and Technology University Model seems better to describe the strain-softening properties of oil sand than Nanshui Model, and able to consider shear dilatancy to some extent.

关 键 词：油砂 三轴试验 应变软化 本构模型 

分 类 号：TU431[建筑科学—岩土工程] TE343[建筑科学—土工工程]