基于修正Lemaitre应变等价性假设的岩石损伤模型  

A constitutive damage model of rock based on the assumption of modified Lemaitre strain equivalence hypothesis

作　　者：李海潮[1] 张升[1,2] 

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学高速铁路建造技术国家工程实验室,湖南长沙410075

出　　处：《岩土力学》2017年第5期1321-1326,1334,共7页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973)项目(No.2014CB047001)~~

摘　　要：基于损伤力学和损伤阀值的概念,认为岩石在较小应力状态下为弹性阶段。当应力达到屈服状态时,发生连续损伤;而当完全损伤时,其应力-应变具有残余强度的变形特征。在此基础上,采用三参数Weibull分布描述岩石损伤演化机制,同时对Lemaitre应变等价性假设进行修正,考虑岩石内部损伤后沿着局部断裂带发生相对滑动变形所产生的滑动摩擦力,最终建立起新的岩石损伤模型。通过与试验结果进行对比分析,结果表明,所建立的损伤模型能够准确地描述岩石在低应力水平下的弹性变形和残余强度变形特征,在实际的工程中具有广泛的适用性。Based on damage mechanics and the concept of damage threshold, rock behaves elastically at the beginning of loading, and successive damage is followed when the stress reaches the yield state. Until rock is completely damaged, the stress-strain curve shows deformation characteristics of residual strength. In this study, three-parameter Weibull distribution function is adopted to describe the evolution of rock damage. Meanwhile, the Lemaitre strain equivalence hypothesis is modified by considering the friction force caused by the relatively slipping deformation of rock along pre-existing local cracks. Finally, a new constitutive damage model is proposed to precisely describe deformation characteristics of residue strength and the elastic deformation at the low confining pressure. Furthermore, the proposed model is also verified by experimental results, which indicates that the model can be widely applied to practical engineering projects.

关 键 词：损伤阀值 三参数WEIBULL分布 Lemaitre应变等价假设 残余强度 本构模型 

分 类 号：TU452[建筑科学—岩土工程]