芒硝力学特性及其本构模型  

Mechanical properties and constitutive model of thenardite

作　　者：刘新荣[1,2] 王军保[1,2] 李鹏[1,2] 郭建强[1,2] 张倩倩[1,2] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045

出　　处：《解放军理工大学学报（自然科学版）》2012年第5期527-532,共6页Journal of PLA University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金创新群体基金资助项目(50621403);国家科技支撑计划子课题资助项目(2006BAJ27B05)

摘　　要：为了解芒硝的力学特性,在MTS815岩石伺服试验机上对其进行了力学试验,包括单轴压缩试验和等围压三轴压缩试验,并对其强度和变形特征进行了分析。分析表明,芒硝在单轴压缩下表现应变软化特性,且强度很低,属于软岩的范畴;当围压在5MPa以上时,芒硝表现明显的应变硬化特征。根据芒硝变形特性,提出了以岩石塑性应变作为微元统计分布变量,同时引入一个能够反映岩石破坏部分承载力的比例系数,建立了能够反映岩石应变硬化特征的损伤统计本构模型,并用试验资料对其进行了验证。结果表明,该模型能够较好地反映芒硝岩样的破坏全过程,且在单轴压缩下,芒硝微元破坏部分承受的力很小,可以忽略;而在高围压作用下,微元破坏部分承受的力比较大,不能忽略。To study the mechanical properties of thenardite, both uniaxial and triaxial compression tests were carried out with MTS815 servo-controlled rock mechanical test system. The experimental results in- dicate that the strength of thenardite under uniaxial compression is very low, and so, it is a kind of soft rock. And it has strain softening characteristics under uniaxial compression but strain hardening character- istics when the confining pressure is more than 5MPa. Then, according to this distortion character of the- nardite, a rock statistical damage constitutive model was established by taking the plastic strain as the dis- tribution variable and a coefficient which can reflect the load capacity of damaged part of rock was intro- duced. Finally, the constitutive model was confirmed by the test data of thenardite. The results show that the proposed model can well reflect the failure process of thenardite. It is reasonable to ignore the load ca- pacity of the damaged part of thenardite under uniaxial compression, but unreasonable to ignore the load capacity of the damaged part of thenardite under triaxial compression.

关 键 词：芒硝 力学特性 应变硬化 本构模型 

分 类 号：TU45[建筑科学—岩土工程]